Patent Description:
The present disclosure relates to a slide staining system comprising a microwave heating systems and, more particularly, to microwave applicators for heating diagnostic tissue specimens and reagents and a method of heating specimens and use of the slide staining system.

A microwave applicator employs microwave radiation to heat an object. Microwave applicators may be used in many different applications ranging from home or personal use for heating foods, to commercial or industrial uses.

Efforts have been made to adapt microwave ovens designed for domestic kitchen use for use in laboratory specimen and reagent heating. Multi-mode microwave systems including those designed for domestic use and commercial laboratory use exist. Further, single-mode microwave systems have been designed for laboratory and industrial use. Both multi-mode and single mode microwave systems rely on a resonant cavity and modal microwaves. However, such devices have inherent disadvantages and limitations which may include: uneven specimen heating due to the variation of microwave energy density within the mode patterns, bulkiness due in part to the requirement for a resonant cavity, complexity in order to control or compensate for variation in energy density with the field to be heated, imprecision, unsuitability for processing single specimens or small groups of specimen, troublesome constraints on specimen orientation and placement, power and voltage requirements, excess heat generation, requirement to use a fixed microwave frequency, and high cost.

Therefore there has been a need for a type of microwave applicator that overcomes the disadvantages and limitations of existing multi-mode and single-mode microwave systems.

<CIT> discloses a slide staining system comprising a microwave heating system, the microwave heating system comprising a microwave source.

<CIT> discloses a microwave heating system a non-modal interplate microwave applicator comprising at least two applicator plates.

The invention comprises a slide staining system comprising a microwave heating system according to the features of claim <NUM>.

The invention also comprises a method for heating a biological tissue on a microscope slide with microwaves in a slide staining system according to the features of claim <NUM> and the use of the slide staining system according to the features of claim <NUM>.

An example not forming part of the invention may comprise a method of pre-treating a biological sample on a microscope slide for histochemical, immunohistochemical, or in situ hybridization processing, the method comprising: positioning the biological sample between plates of a non-modal interpolate microwave applicator; connecting a microwave source to the non-modal interpolate microwave applicator; applying an electromagnetic field between the plates to the biological sample on the microscope slide; and heating the sample to perform at least one staining pre-treatment protocol step.

An example not forming part of the invention may comprise a method of incubating a biological sample on a microscope slide for histochemical, immunohistochemical, or in situ hybridization processing, the method comprising: positioning the biological sample between plates of a non-modal interpolate microwave applicator; connecting a microwave source to the non-modal interpolate microwave applicator; applying an electromagnetic field between the plates to the biological sample on the microscope slide; and heating the sample to perform at least one staining pre-treatment protocol step.

An example not forming part of the invention may comprise a method of in-line heating of a fluid for histochemical, immunohistochemical, or in situ hybridization processing, the method comprising: positioning a fluid carrier carrying fluid between plates of a non-modal interpolate microwave applicator; connecting a microwave source to the non-modal interpolate microwave applicator; applying an electromagnetic field between the plates to the fluid; and heating the fluid.

An example not forming part of the invention may further comprise monitoring a characteristic of a load; and adjusting the electromagnetic field between the plates in response at least in part to the monitoring.

As used herein, non-modal interplate microwave applicator is any microwave applicator having at least two plates adapted to receive a load between the plates, wherein the microwave applicator is configured to generate an electromagnetic field between the plates for the purpose of applying microwave energy to the load, and wherein the strength of the electromagnetic field at the load is not designed to depend on standing wave modes formed within a resonant enclosure.

The term microwave source, as used herein, refers to any device that generates electromagnetic radiation in a frequency range from about <NUM> to <NUM>.

The term plates is intended to refer to surfaces comprising at least partially conductive materials such as conductors, semiconductors, metals. Plates may comprise planar surfaces that are parallel, partially parallel, or non-parallel. Plates may also comprise non-planar surfaces such as cylinders, spheres, or any geometric two-dimensional or three-dimensional shape in which there a fixed or variable area for each surface and an fixed or variable distance between surfaces.

The various embodiments of the invention presented herein illustrate how to practice the invention and the various advantages the invention has over existing methods.

By directly heating a load using a non-modal interplate microwave applicator as described herein or equivalent variations thereof, a number of beneficial effects may be achieved including that the non-modal interplate microwave applicator may be made very small, it may require only a very low power while providing uniform, well-controlled heating of loads positioned between the plates; the non-modal interplate microwave applicator may be formed automatically by bringing the plates together automatically which enables a load to be inserted in or removed from between the plates of the applicator; the non-modal interplate microwave applicator may be built into load holders that move from station to station; independent applicators for a plurality of loads may be grouped together in a compact manner to heat trays, racks, or containers very quickly; a shielding enclosure may enclose the non-modal interplate microwave applicator without acting as a modal resonant cavity, i.e. a cavity resonator.

The non-modal interplate microwave applicator may be tuned or adjusted electrically both by including an electromagnetic tuning device, e.g. an RLC circuit, and by adjusting the impedance of the plates by adjusting the distance between the plates or the area of the plates. The electrical characteristics of the applicator may also be affected by adjusting the frequency of the microwave source; the plates of the non-modal interplate microwave applicator may have various shapes, sizes and surfaces that enable loads such as tubes, tissue cassettes, flow reactors, or any object to be heated; the plates and the nonresonant enclosure may include apertures that enable temperatures such as a load temperature, or other measurable properties for example such as fluorescence, to be measured using either contact or non-contact sensors or may enable reagents to be dispensed through the enclosure and the plates.

The above beneficial effects and other advantages that non-modal interplate microwave applicators may have, compared with single-mode and multimode microwave systems, are illustrated in the drawings and discussed in greater detail below. The embodiments described herein are exemplary and one skilled in the art can readily see that many equivalent embodiments and applications may be implemented within the scope of the invention.

<FIG> illustrates a multi-mode microwave applicator <NUM>, with a load <NUM> on load holder <NUM> e.g. a microscope slide positioned within the applicator. An applicator is a device for transferring electromagnetic energy from a source to a load. As illustrated with respect to microwave applicator <NUM>, a microwave source <NUM> emits microwave energy into a resonant cavity <NUM>. Microwaves typically have wavelengths between <NUM> and <NUM> meter and operate in a frequency range between <NUM> and <NUM>. A microwave source <NUM> with a frequency of <NUM> has a penetration depth suitable for many applications including laboratory reactions. The wavelength of microwaves at <NUM> is about <NUM> in air. In microwave applicators that include a resonant cavity the microwave energy develops a modal pattern of standing waves <NUM> with minima and maxima. This leads to corresponding patterns of high energy density and low energy density or hot and cold spots representing the minima (or nodes <NUM>) and maxima (anti-nodes <NUM>) of the multi-mode pattern in the cavity. Multi-mode microwave applicators that have a resonant cavity <NUM> are typically dimensioned to have a size that is typically several wave lengths in all three dimensions. The mode pattern with its regular minimum and maximum will vary depending on the position of the load and the dielectric properties of the load. This makes it very difficult to control such an applicator especially if the load <NUM> is small compared to the cavity dimensions and has varying dielectric properties and volume from time to time such as for reaction mixtures and tissue samples. In some multi-mode microwave applicators, devices such as a mode stirrer or field stirrer <NUM> may be included to change the modal pattern of the microwave radiation within the cavity in order to reduce the unevenness of the heating of the load. Further, a turntable <NUM> may be included to move the load <NUM> through the mode patterns also to reduce the unevenness of the heating of the load. Since heating may be uneven, laboratory techniques using microwave heaters often include a liquid load which is heated to have a thermal and electromagnetic stabilizing effect, again to reduce the unevenness of the heating. Heat from the liquid may be transferred to the sample so that a significant portion of the microwave heating is indirect.

<FIG> illustrates a single-mode microwave applicator <NUM> with a microwave source <NUM> that generates microwave energy which forms a standing wave <NUM> having nodes <NUM> and antinodes <NUM>. The resonant cavity <NUM> is dimensioned to have the desired resonance characteristics which enable the desired mode pattern. For example, a waveguide for <NUM> microwaves may typically have a dimension of <NUM> x <NUM>. The load holder <NUM> may be placed so as to position the load <NUM> at an antinode or maximum within the standing wave. Since the presence of a load <NUM> may affect the position of the minima <NUM> or nodes and maxima <NUM> or antinodes of the mode patterns, a physical tuning device <NUM> such as a stub of a conducting or absorbing material be positioned and moved back and forth using slot <NUM> within the cavity <NUM> to adjust the position of the minima <NUM> and maxima <NUM>.

<FIG> illustrates another single-mode microwave applicator <NUM> with a microwave source <NUM>. A wave guide <NUM> is configured in a circular shape surrounding an inner cylinder <NUM>. Inner cylinder <NUM> includes a series of slots <NUM> that act as antenna slots. The microwave energy <NUM> enters the inner cylinder <NUM> through the slots <NUM>. Which of slots <NUM> the microwave energy <NUM> enters through may change depending upon the load <NUM> in the load holder <NUM>, thus the microwave energy <NUM> may be focused or tuned automatically without manually adjusting a physical tuning device.

However, the single-mode microwave applicators illustrated in <FIG> are typically best suited for heating a single cylindrical load such as liquid in a reaction vial. As mentioned above, multi-mode microwave applicators require relatively large resonant cavities with the correct dimensions in order to function properly.

With single mode applicators, the size of the resonant cavity is smaller, but this can also be a problem because such small dimensions can make it difficult to insert or remove a load such as one or more microwave slides. Additionally it is difficult to position a load such as a microwave slide with a sample to be heated appropriately in a single-mode microwave applicator because some parts of the sample may be located at the point of maximum energy density of the standing wave while other parts of the sample may be offset slightly or significantly, thus uneven heating which could be less noticeable with a small reaction vial may be very uneven and troublesome on a tissue sample on a microwave slide.

<FIG> illustrates a non-modal interplate microwave applicator <NUM> that includes a first plate <NUM> and a second plate <NUM>. The plates <NUM> and <NUM> may be of any suitable material such as metal or other conductors or they may be of semiconductors. Plate <NUM> is illustrated as having a width (a) and length (b). A separation distance (s) separates plate <NUM> and plate <NUM>. The impedance of applicator <NUM> is determined, at least in part, by dimensions (a and b) of the two plates <NUM> and <NUM> and the distance (s) between the two plates. The impedance of applicator <NUM> should be appropriately matched to the intended load <NUM> in order to provide heat.

Applicator <NUM> surrounds the load <NUM> partly or completely and the distance (s) between the plates <NUM> and <NUM> is typically less than λ/<NUM> where λ is the wavelength of the applied microwaves. In other embodiments the distance (s) between the plates <NUM>, <NUM> may be larger than λ/<NUM>, for example it could be λ/<NUM> in some cases. The distance (s) should be sufficiently great to avoid arcing and sufficiently small to provide an even field of microwave energy to the load.

The dielectric properties e.g. dielectric constants, of substances e.g. air or other fluid, and the load <NUM> between plates <NUM> and <NUM> also affect the impedance of applicator <NUM>. The size and form of the plates <NUM> and <NUM> and the distance (s) can have any value that creates the appropriate impedance of the applicator. In many embodiments, plate <NUM> and plate <NUM> both have the same or similar dimensions but there may be applications where the dimensions of <NUM> and <NUM> may differ, for example as illustrated in more detail below in the description of <FIG>. Further plate <NUM> may in some embodiments be made of a different material than plate <NUM>.

<FIG> illustrates a non-modal interplate microwave applicator <NUM> that includes plates <NUM> and <NUM> which are connected via transmission lines <NUM> to microwave source <NUM>. A load holder <NUM> with a load <NUM> is positioned between plates <NUM> and <NUM>. When microwave source <NUM> generates microwave energy, a substantial portion of the electromagnetic field, i.e. microwave energy <NUM> passes between plates <NUM>, <NUM> through the load <NUM>. Electromagnetic radiation, i.e. microwave energy <NUM> may also be transmitted away from the plates but standing waves like those in a single-mode or multi-mode microwave applicator will not build up if care is taken to ensure that any enclosure surrounding the applicator <NUM> does not act as resonant cavity.

In the non-modal interplate microwave applicator <NUM> and in the other embodiments of the invention, the RF voltage between the plates <NUM>, <NUM> is substantially the same everywhere because the area of the plates is small compared to the wavelength.

When two plates <NUM>, <NUM> are parallel and separated by a dielectric, e.g. a gap with air, fluid, or other dielectric, there is continuity of displacement current across the boundary between the plates. Likewise, if a second dielectric, e.g. a dielectric load holder <NUM>, partially fills the gap there will be continuity of displacement current across the boundary of the two dielectric regions. The relative values of the electric field inside and outside the load can be determined. The electric field or microwave energy <NUM> inside the load is the source of heating.

In this case of two dielectrics filling the gap, one being air and one being the load, continuity of displacement current means that the vector D has the same amplitude in both regions. Thus,
<MAT>
and so
<MAT>.

Thus the electric field is less in the load than in the airspace by the factor of (<NUM> / ε2').

Continuity of displacement current across a dielectric boundary means the component of displacement current normal to the boundary interface is at its maximum and this is used in the non-modal interplate microwave heating applicator.

<FIG> illustrates a microwave heating system <NUM> that includes a nonresonant enclosure <NUM> and an applicator <NUM> formed by two metal plates <NUM> and <NUM> surrounding a load <NUM> on load holder <NUM>. The nonresonant enclosure <NUM> may have various dimensions and may be formed from various materials.

The applicator <NUM> is connected to a microwave source <NUM> (e.g., microwave generator) via a transmission line <NUM>, for example, a coaxial cable. The nonresonant enclosure <NUM> may be configured to be nonresonant by selecting dimensions to fulfill cutoff conditions for a selected frequency.

The impedance of applicator <NUM> may be matched appropriately by selecting suitable dimensions or by using one or more electrical tuning devices <NUM> that vary the electromagnetic characteristics of the microwave energy coming from the source <NUM> to the plates <NUM>, <NUM>. For example, by tuning the Resistive/Inductive/Capacitive (RLC) characteristics of the tuning device <NUM>, the overall impedance matching of applicator <NUM> can be adjusted, thereby affecting the efficiency of the heating system. Tuning device <NUM> as referred to herein is generally a network containing either passive or active components that attempts to match the impedance of the active device to a transmission line. By monitoring, for example, the reflected power or the temperature of the load and using that as a feedback signal to the tuning device, the applicator can be tuned to optimize the heating efficiency of the system.

It should be noted that when the term impedance or impedance matching is used herein with respect to an applicator, the term generally refers to an applicator having some degree of impedance matching between the applicator and the load. The degree of impedance matching can vary during the heating process and between different loads and run conditions. The degree of impedance matching can vary from close to zero to <NUM>%. As long as the applicator has a degree of impedance matching, a certain amount of energy will be transferred to the load. It should be noted that impedance matching does not mean that the impedance conditions have to be maximally matched or near optimally matched during any period of the process. It is sufficient to have some degree of impedance matching in the applicator. The total energy transferred to the load will be a function of the efficiency and the amount of power applied to the applicator. Many different applications, some of which are described herein can be performed with a very low efficiency without losing microwave heating performance. Also, the field concentrating effect and uniform heating will remain even with a very low efficiency in the system.

A general, non-modal applicator made of two conducting plates will create an electromagnetic field between the plates if a microwave signal is provided between the plates. The field will have a strong electrical component between the plates largely contributing to the heating of any dialectical load placed between the plates. In practice, a general applicator of this type will more or less radiate an electromagnetic field in all directions whereby it may be desirable to have a shielding enclosure. However, if the shielding enclosure has dimensions correlating to resonant conditions at the given frequency the enclosure may act as a resonance cavity resonating above cut-off frequency and thus create a mode pattern with standing waves inside the enclosure which can disturb the function of the applicator and make the applicator less controllable. For example, as mentioned above, a waveguide for <NUM> microwaves may typically have dimensions of <NUM> x <NUM>. Therefore nonresonant enclosure <NUM> could have dimensions smaller than <NUM> x <NUM> in at least one dimension. For example nonresonant enclosure <NUM> could be dimensioned <NUM> x <NUM> or smaller, thus inhibiting the creation of standing waves within nonresonant enclosure <NUM>. Larger or smaller dimensions may be used as long as care is taken to inhibit the creation of standing waves that could affect the field between plates <NUM> and <NUM>.

By keeping the dimensions of the enclosure less than dimensions correlating to resonant conditions i.e. below cut-off frequency, this disturbance can effectively be avoided. Another way to achieve a nonresonant enclosure is to include an absorbing or attenuating material in the enclosure. This is one way that a shielding enclosure could be used while still having dimensions greater than for cut-off conditions.

As used herein, nonresonant enclosure refers to an enclosure that encloses or at least partially encloses a microwave applicator without creating significant mode patterns or standing waves, and without relying on the enclosure to focus or otherwise concentrate the microwave energy in order to heat.

The nonresonant enclosure <NUM> may include an electrically conducting surface and in the illustrated embodiment is rectangular in profile. For example, the nonresonant enclosure <NUM> may form an electrically conducting cavity constructed from aluminum, copper, brass, semiconducting material or a combination of materials, etc. However, it should be noted that other materials may be used.

The various examples do not rely upon the nonresonant enclosure to build up maxima or hot spots through standing waves or to otherwise reflect, focus or concentrate the microwave energy in order to create a concentrate field of microwave energy. However, the nonresonant enclosure <NUM> may serve as an electromagnetic shield to inhibit or prevent microwave radiation from escaping or otherwise generating electromagnetic interference that might affect items outside the nonresonant enclosure. Accordingly, the material of the nonresonant enclosure may have apertures or holes or may be made of mesh which acts as an electromagnetic shield.

Also, it should be noted that the nonresonant enclosure <NUM> may have a different shaped profile other than rectangular, for example, spherical, elliptical, cubic, triangular, cylindrical etc. The nonresonant enclosure <NUM> may be shaped and sized based on and configured to receive therein a complementary shaped load holder <NUM>, for example, a microscope slide or a reaction vial, which may be removable therein or permanently secured therein. Although various examples of the microwave applicator <NUM> are very suitable for heating planar loads such as microscope slides and tissue cassette, it should be noted that the various examples also are not limited to a reaction vial or a glass slab, but a container or structure may be provided that is of any type that can receive therein or on its surface a fluid or other object. For example, instead of a reaction vial, a bulb, tube, a capillary structure, a thin film substrate, glass slab, microscope slide, micro titer plate, micro fluidic devices, micro arrays, micro fabricated structures, etc. may be provided.

Moreover, the cutoff frequency for the nonresonant enclosure <NUM> in one embodiment is determined by the dimensions height (h), width (w), and depth (d) of the nonresonant enclosure <NUM>. Accordingly, the dimensions in many embodiments are selected to be small enough to prevent the modal propagation of certain microwaves, for example, <NUM> microwaves.

The applicator <NUM> is configured to substantially surround the load <NUM>. Accordingly, in operation, a very broadband frequency and a homogenous electric field that couples and interacts with the load <NUM> in many places is provided. It should be noted that the applicator can have any dimensions as long as the impedance of the applicator and the load are sufficiently matched to provide the desired heating effect.

The applicator <NUM> is formed from metal plates dimensioned to sustain the required output power. The output power may be very low in comparison with the output power required by single-mode or multi-mode resonant cavity microwave applicators. For example, the output power might be from <NUM> milliwatts to <NUM> milliwatts, <NUM> milliwatts to <NUM> watt, <NUM> watt to <NUM> watts, or <NUM> watts to <NUM> watts or more depending on the size and configuration of the plates, the load to be heated, and the characteristics of the microwave source.

The applicator <NUM> may be formed from one millimeter (<NUM>) thick plates <NUM>, <NUM>, such as copper, gold, brass, aluminum, metal coated structures with a core of non-conducting materials such as polymers, semiconducting materials or combination of mentioned materials. The plates <NUM>, <NUM> may be thick enough to sustain an electric field generated by, for example, <NUM> watts to <NUM> watts of power or more. The applicator <NUM> may also be formed from a printed circuit board arranged around the load. The printed circuit board can be of a flexible type that can be formed around the load. The applicator can also be stereo lithographically printed on a substrate and arranged around the load.

In operation, the load <NUM> is placed or secured inside or partially inside the applicator <NUM>. A homogeneous electric field will be established between the two applicator plates and accordingly the load will be exposed very evenly to the electromagnetic field, thereby generating a very uniform heating of the load. For many typical embodiments, electric field propagated from the applicator <NUM> is also contained within the conductive enclosure, namely the nonresonant enclosure <NUM>. However, since very low power may be used in the various embodiments, a very low degree of shielding or in fact no shielding may be required.

It should be noted that the various examples can be operated using a multiple microwave source <NUM> and applicator <NUM>, which in the various embodiments is either a single ended applicator or a balanced applicator. The applicator <NUM> can be made to have broadband to narrowband characteristics with corresponding low Q to high Q values. Accordingly, the applicator <NUM> can have a sufficiently matched impedance with the load over a wide band of frequencies. The frequency band characteristics can be chosen depending on the application. Often a broadband characteristic is desired where the applicator is not highly matched to a particular frequency. Thus, the configuration of the microwave heating system <NUM> is less dependent on the load <NUM> to be heated.

In various examples, the applicator type can be either be a balanced applicator as shown in <FIG>, or a single-ended closed-loop applicator where one end can be connected to earth, as shown in <FIG>. The balanced applicator can be fed symmetrically using a balance-to-unbalance transformer (balun). A balun as used herein refers to a device that converts a single-ended transmission line to a symmetrical pair of transmission lines having exactly the same properties and symmetrical to ground. A single ended applicator as used herein refers to an applicator fed by a single transmission line and usually fed at one end. A balance applicator as used herein refers to an applicator that is fed by two symmetrical transmission lines with respect to ground. It should be noted that in all described embodiments, all described types of applicator can be used even if only one type is described in a specific embodiment.

The characteristics of the applicator and thereby the generated electrical field can be adjusted or customized to surround the load by combining certain values of the applicator parameters such as the area of the applicator plates, the plate dimensions (a) and (b), and the separation distance (s) between the applicator plates, and the physical form of the plates. By changing these parameters the electrical field can, for example, be evenly distributed over the load. The electric field strength and distribution is also affected by any dielectric material introduced between the applicator plates. The load holder and other holding structures and components will contribute to the electric field distribution in the applicator. However, any enclosure such as nonresonant enclosure <NUM> should be dimensioned or otherwise configured so as to avoid causing standing waves to build up as occurs with single-mode and multi-mode microwave applicators.

Referring again to <FIG>, the plate dimensions (a) and (b), the separation distance (s) between the applicator plates and the physical form of the applicator <NUM> determines an impedance and center frequency for the applicator <NUM>. Accordingly, depending upon the application or use for the microwave heating system <NUM>, the plate dimensions (a) and (b), the separation distance (s) between the applicator plates, and the physical form of the plates may be adjusted accordingly, for example, to provide desirable, required or optimum dimensions. The shape of the plates can have any geometric shape such as elliptic, circular, square, rectangular, triangular, octahedral, polyhedral, or any other single or double curved surfaces.

In the various examples, the applicator <NUM> is a single ended applicator or a balanced applicator that covers part of or the entire load <NUM>. However, it should be noted that the load <NUM> in some embodiments may extend beyond the ends of the applicator <NUM>.

<FIG> illustrates a non-modal interplate microwave applicator <NUM> that may be substantially similar to the balanced embodiment illustrated in <FIG> with an added center plate <NUM> that connects to ground. The added center plate enables two loads <NUM> and two load holders <NUM> to be positioned between the plates such that a balanced non-modal interplate microwave applicator is formed and the load capacity is doubled. Other embodiments of a three-plate or even "n"-plate non-modal microwave applicators can be constructed using planar plates, undulated plates, cylindrical plates or any type of plates by connecting a microwave source to one plate and a ground to the adjacent plate and repeating this structure "n" times.

<FIG> illustrates a non-modal interplate microwave applicator <NUM> with a nonresonant enclosure having a microwave attenuating inner surface <NUM>. Depending on the power being applied, the microwave attenuating inner surface <NUM> may be beneficial in some embodiments to prevent build up of mode patterns, standing wave, or other interfering signals that might interfere with the desired operation of the applicator <NUM>. In embodiments where the power is low, the need for a specifically microwave attenuating surface may be diminished. The microwave applicator <NUM> has a microwave source <NUM> that is connected in a balanced configuration to a tuning device <NUM> and to plates <NUM> and <NUM>. A load <NUM> is positioned on a load holder <NUM> between plates <NUM> and <NUM>. Enclosure <NUM> may have dimensions that prevent build up of modal microwave energy, i.e. smaller than the wavelength of the desired cutoff frequency. However, other dimensions may also be used for the enclosure <NUM> while maintaining substantial nonresonance. A surface <NUM> that is substantially non-reflective to the desired microwave frequency may be included. The surface <NUM> may be formed of microwave attenuating material or may be coated with a microwave attenuating coating. Examples of microwave attenuating material may include many types of absorbing or scattering materials such as conductive foam or microwave absorbing paint that includes thin conducting fibers such as stainless steel fibers or carbon or graphite mixed paint or other coating material.

<FIG> shows that a microwave attenuating surface <NUM> may be included in enclosure <NUM> to create a nonresonant enclosure. The microwave attenuating surface <NUM> may include elements used in anechoic chambers such as cones, baffles, pyramids, or other protruding physical structures designed to trap and attenuate microwaves.

To illustrate certain advantages of non-modal interplate microwave applicator such as those described in <FIG> and <FIG>, consider that conventional multimode microwave applicators that rely on the creation of standing waves or modal patterns including resonant cavities would in general be too bulky for integration in to multiple stations within a single instrument. Those types of applicators have been described above with reference to <FIG>. Further, those types of applicators are not well adapted to handle multiple flat specimens on microscope slides. However, non-modal interplate microwave applicators such as those describe in the various embodiments of the invention may be very well suited for multiple instantiations within a single instrument especially where the loads are small planar loads such as microwave slides and also for inline heating of tubing which may carry rinse or other fluids or reagents to the microscope slides.

<FIG> is a diagram of an automated slide staining system <NUM> which serves as one example of how various embodiments of the non-modal interplate microwave applicator may be adapted for multiple uses within an instrument. Because the various embodiments of non-modal interplate microwave applicators can be made to be compact, and to use relatively low power in comparison to microwave applications with resonant cavities, such embodiments may be very beneficial to be used in instruments or systems such as the automated slide staining system <NUM>. Further automated slide staining system <NUM> is configured to process multiple samples in parallel which processing requires controlled heating various points in the staining process. Additionally, interplate microwave applicators as described herein have the benefit of being very well suited to heat where multiple independent controllable heaters are required. Also, non-modal interplate microwave applicators may be configured to heat flat loads such as cells or tissues on microscope slides, tissue cassettes or any load that fits between the plates such as tubing or trays.

The automated slide staining system <NUM> includes a user interface <NUM> which may include an embedded PC and display screen. The automated slide staining system may include slide handling apparatuses such as a cover slipper <NUM> and a slide rack transport robot <NUM> that conveys slide racks with microscope slides to be stained from a slide rack port <NUM> to various processing stations. Processing stations may include: a waiting station <NUM> where slides in slide racks are held prior to, during or after other processing steps; a baking station <NUM> where tissue samples are baked to ensure adhesion of the sample to the slide; a dewaxing station <NUM> where paraffin is removed from the samples on the slides; a target retrieval station <NUM> where heat induced epitope retrieval is performed; an immunohistochemistry (IHC) staining module <NUM>; an in-situ hybridization (ISH) staining module <NUM>. Staining system <NUM> may include a robot probe <NUM> that moves between reagent mixing and probe wash station <NUM>, reagent station <NUM>, and staining modules <NUM> (IHC) and <NUM> (ISH). Bulk fluid bottles <NUM> may contain fluids for rinsing and buffering, and may be connected to valves <NUM> and pump <NUM> to deliver fluids to target retrieval station <NUM>, dewax station <NUM>, IHC staining module <NUM>, and ISH staining module <NUM>. Waste fluids from stations and modules may be connected to waste containers <NUM> through fluid management module <NUM>. A control module <NUM> may include a microwave source <NUM> which connects to the modules requiring a microwave source.

<FIG> is an orthogonal view of a diptank module <NUM> with individual diptanks <NUM>. A slide rack <NUM> may be inserted into one of the diptanks <NUM>. A very clear advantage of using an embodiment of the invention, i.e. the non-modal interplate microwave applicator, in such an application is that multiple diptanks <NUM> each having an independent non-modal interplate microwave applicator can be placed together in close proximity. It would be very difficult to achieve closely joined but independent microwave diptank applicators using either single mode or multi mode microwave applicators which require resonant cavities.

<FIG> illustrates an end view of a diptank <NUM> with a non-modal interplate microwave applicator. Plates <NUM> and <NUM> are connected via transmission line <NUM> to a microwave source <NUM>. The load <NUM> may be a tissue sample that is to be deparaffinized via heating in a liquid <NUM>. In this embodiment, the plates <NUM>, <NUM> may be immersed in a paraffin-removing liquid <NUM> contained in a liner or container <NUM>. Container <NUM> may be made of any material that does not act as a resonant cavity. It may further be made of material that either conducts or transfers heat well or alternatively a material that insulates well depending on whether the particular application requires heat to be retained or dissipated. In some applications it may be advantageous to coat plates <NUM>, <NUM> and transmission line <NUM> so that it is not directly exposed to liquid <NUM>. Such coating of course may be designed to be substantially transparent to microwaves. A slide rack <NUM> holding one of more slides / load holders <NUM> may be introduced into the diptank <NUM> and fluid may enter or leave the diptank through a port <NUM> at the bottom of diptank <NUM>. A nonresonant enclosure <NUM> surrounds a liquid container <NUM> and may act to shield adjacent diptanks <NUM> and their contents from microwave radiation emitted from plates <NUM> and <NUM>. The nonresonant enclosure <NUM> may be dimensioned to be small enough to prevent standing waves from developing. Alternatively nonresonant enclosure <NUM> may be made nonresonant using materials or coatings that attenuate or prevent build up of standing waves. Although the plates <NUM>, <NUM> are depicted as both being positioned with the liquid <NUM> and the container <NUM>, other embodiments in which the plates <NUM>, <NUM> are external to container <NUM> may be constructed.

In some examples, pretreating of biological sample <NUM> on microscope slide <NUM> may be performed by positioning sample <NUM> between plates <NUM> and <NUM> which form a non-modal interpolate microwave applicator. A microwave source <NUM> is connected to microwave applicator plates <NUM> and <NUM> and an electromagnetic field is generated between the plates thus heating the load, i.e. sample <NUM>. Various pretreatment steps involve heating. For example, dewaxing by heating fluid <NUM> to a temperature above the melting point of wax may be performed. Fluid <NUM> may comprise a fluid suitable for heat induced target retrieval such as a target retrieval buffer. The non-modal interpolate microwave applicator comprising plates <NUM> and <NUM> may apply a field to heat fluid <NUM> to a suitable temperature for heat induced target retrieval, for example <NUM> degrees C. In some embodiments dewaxing and target retrieval may be performed simultaneously.

For in situ hybridization processing, a pretreatment step may comprise a denaturation step which may be performed at <NUM> to <NUM> degrees C or any desired temperature.

The same or similar methods may be performed using examples illustrated in <FIG> and described below.

<FIG> illustrates a diptank <NUM> with a non-modal interplate microwave applicator that is similar to the embodiment illustrated in <FIG> and described above. In some applications there may be a benefit to positioning the plates <NUM>, <NUM> so that they do not contact liquid <NUM> directly and do not require any special coating. In the embodiment of <FIG> the non-modal interplate microwave applicator comprises plates <NUM>, <NUM> which are position outside liner or container <NUM>. Plates <NUM>,<NUM> connect via transmission line <NUM> to microwave source <NUM>. A slide rack <NUM> having a slide <NUM> that includes a tissue sample or load <NUM> may be positioned within the non-modal microwave applicator plates <NUM>, <NUM> and heated directly, quickly, precisely through the walls of container <NUM> and through the liquid <NUM>. Nonresonant enclosure <NUM> acts as an electromagnetic shield but not as a cavity resonator by either being dimensioned so as to prevent mode patterns from building or by attenuating the microwaves. <FIG> illustrate a non-modal interplate microwave applicator being used in a drying or baking module <NUM>. A slide rack <NUM> with a slide <NUM> and tissue sample or load <NUM> may be positioned between plates <NUM>, <NUM> which connect via transmission lines <NUM> to microwave source <NUM>. Nonresonant enclosure <NUM> acts as an electromagnetic shield around the plates and load. If the baking module <NUM> were to utilize forced hot air from conventional applicators to bake slide <NUM>, a fairly large enclosure such as enclosure <NUM> may be used to enable greater airflow and convection. However a non-modal interplate microwave applicator can perform baking without depending on airflow and the accompanying large enclosure size. This also illustrates the concept that some embodiments of non-modal interplate microwave applicators may be utilized to retrofit or replace conventional applicators because they can be constructed to be relatively small.

<FIG> illustrates a capillary staining module <NUM> which can be either an immunohistochemistry staining module <NUM> or an in-situ hybridization staining module <NUM> as illustrated in <FIG> and the accompanying description above. As with the other exemplary modules described above, a slide rack <NUM> may be introduced into capillary staining module <NUM> for processing.

After a reagent <NUM> has been dispensed onto the sample <NUM>, slide rack <NUM> and lid <NUM> may be brought together, by rotation or any relative movement of one or both of slide rack <NUM> and lid <NUM> so that plate <NUM> and plate <NUM> form a non-modal interpolate microwave applicator connected to microwave source <NUM>. This non-modal interpolate microwave applicator may then be used to incubate the sample. In some embodiments it may be desirable to perform incubating of the sample with an antibody reagent, a molecular probe, a detection reagent, a visualization reagent or any desired reagent for a period of time at a desired temperature. For example, antibody incubation may be performed at a temperature above room temperature such as <NUM> degrees C in order to speed up the immunohistochemical reaction. In other embodiments incubation with a molecular probe for in situ hybridization may be performed at any temperature between <NUM>-<NUM> ° C.

With some very fast protocols, it is advantageous to heat a rinse buffer <NUM> that is dispensed onto slide or load holder <NUM> that is held by slide rack <NUM>. By so doing the temperature of the load holder <NUM> and the load <NUM> can be maintained at a temperature nearer a desired incubation temperature rather than being cooled by applying a cold rinse. Heating the rinse buffer <NUM> may be accomplished by passing it through a tube <NUM> which when full of fluid <NUM> acts as a load to non-modal interplate microwave applicator <NUM>.

<FIG> shows non-modal interplate microwave applicator <NUM> which comprises plates <NUM> and <NUM> with the load <NUM>, e.g. fluid filled tube bending through between plates <NUM> and <NUM>.

<FIG> illustrates a staining module <NUM> which is configures to pivot a slide rack <NUM> which holds a load holder <NUM> e.g. a microscope slide, so that it can be positioned near and substantially parallel to a cover or lid <NUM> so that a capillary gap is formed between the lid <NUM> and the slide <NUM> when they are brought together. A fluid <NUM> such as a buffer may be dispensed from a dispensing nozzle <NUM> onto the load holder <NUM> and the load <NUM>, e.g. a tissue sample that is to be stained or otherwise processed. The fluid to be dispensed may be heated using non-modal interplate microwave applicator <NUM> wherein a load <NUM>, e.g. a fluid filled tube passes through plates <NUM> and <NUM> which heat the load <NUM> when microwave energy is applied through transmission line <NUM> from microwave source <NUM>. The liquid <NUM> continues through a bubble trap and dispenser system <NUM> up to the nozzle <NUM>.

A reagent may be dispensed through opening <NUM> onto slide <NUM>. For example an antibody or a molecular probe may be dispensed so that it contacts the load <NUM>, i.e. sample.

Also illustrated in <FIG> is a plate <NUM> positioned next to the lid <NUM> and a second plate <NUM> positioned next to load holder <NUM>. When load holder, e.g. slide, <NUM> and lid <NUM> are brought together to form a capillary gap, plates <NUM> and <NUM> which are connected via transmission line <NUM> to microwave source <NUM>.

Both the inline fluid heating and the microscope slide incubation heating are exemplary embodiments that illustrate the diverse applicability of the non-modal interplate microwave applicator.

<FIG> depict a target retrieval module <NUM> with a slide rack <NUM> that may be inserted into module <NUM>. The load holder or slide <NUM> with a load or tissue sample <NUM> may be positioned between plates <NUM>, <NUM>, which connect to microwave source <NUM> through transmission line <NUM> and are surrounded by nonresonant enclosure <NUM>. In this embodiment, individual non-modal interplate microwave applicators with plates <NUM>, <NUM> may compass separate diptanks <NUM> so that the fluid <NUM> in each diptank may be the same type of fluid or a different type of fluid and the heating temperature of the fluid may be controlled independently for each sample. In an immunohistochemistry application where different target retrieval solutions and different heating conditions may be advantageous for each slide, such an embodiment may be well-suited.

<FIG> illustrates a robot probe <NUM> with a pipette tip <NUM> which is in fluid connection with a length of tubing <NUM> wound about a cylinder which includes an inner cylinder plate <NUM>. An outer cylinder plate <NUM> at least partially surrounds the wound tubing <NUM> to form a non-modal interplate microwave applicator that may be used to heat the load <NUM> i.e. the wound portion of the tubing <NUM>. The plates <NUM> and <NUM> of the non-modal interplate microwave applicator connect via transmission line <NUM> to microwave source <NUM> and are enclosed by nonresonant enclosure <NUM>. Such an embodiment illustrates how a non-modal interplate microwave applicator may heat a fluidic load in an inline manner and thus enable heating of a fluid to be dispensed by a robotic probe while maintaining a compact robot fluidics design.

<FIG> shows a cylindrical non-modal interplate microwave applicator <NUM> using the same principle of a non-modal interplate microwave applicator as used in <FIG> with a cylindrical applicator <NUM> corresponding to planar plate applicator <NUM>. The cylindrical applicator plate analogous to applicator plate <NUM> in <FIG> is formed in the embodiment of <FIG> as an outer cylinder <NUM> and an applicator plate analogous to applicator plate <NUM> in <FIG> formed in the embodiment of <FIG> as an inner cylinder <NUM>. The load <NUM> to be treated is placed between the outer cylinder <NUM> and the inner cylinder <NUM>. The outer cylinder <NUM> and the inner cylinder <NUM> form together the non-modal interplate applicator in the microwave heating system <NUM>. The cylinders <NUM> and <NUM> connect to microwave source <NUM> through transmission line <NUM> and may include a tuning device <NUM>. The non-modal interplate microwave applicator may be a balanced configuration as shown in <FIG> or a singled-ended configuration as shown in <FIG>. Cylindrical plates <NUM>,<NUM> can be made of a conducting or semiconducting material. The cylindrical form of <NUM> and <NUM> is just an example of a possible geometric form. <NUM> and <NUM> can have any form as long as the load can be, at least partially placed between the applicator plates. The system <NUM> may also include a nonresonant enclosure <NUM> that may act as a shield to prevent the propagation of microwaves at the applied frequency outside the system and create appropriate boundary conditions inside the enclosure <NUM>. The characteristics of the heating system will be governed by the dimensions d, D and L as defined in <FIG>.

A balanced applicator that is fed from an unbalanced source may be connected via a balance-to-unbalance transformer (balun). A balanced applicator is constructed symmetrically with respect to the feed point and preserves symmetry with respect to ground thus avoiding unbalanced currents and unwanted radiation in the transmission feed line. This ensures all energy is radiated more efficiently from the applicator. The balun <NUM> can be physically placed anywhere between the microwave source <NUM> and the beginning of the applicator <NUM>. The balanced applicator parts and <NUM>, <NUM> can have the same design, dimensions and features as the herein described single ended applicators parts.

<FIG> illustrates a non-modal interplate microwave applicator that includes a supporting structure <NUM>. The supporting structure <NUM> supports and maintains the position of the load holder <NUM> and the load <NUM> within the system <NUM>. The supporting structure <NUM> may be formed of any suitable microwave transparent or microwave semitransparent material, for example, a polytetrafluoroethylene (PTFE) material, such as Teflon. Also, the microwave heating system <NUM> can be made nonresonant by configuring the dimensions of the enclosure <NUM> to achieve frequency cutoff conditions as described herein. Similar to the descriptions of other embodiments, plates <NUM>, <NUM> connect via connectors <NUM>,<NUM> to transmission lines <NUM>,<NUM> to microwave source <NUM>. Various shapes or forms of plates may be used in the various embodiments of the non-modal interplate microwave applicator. Some examples of plate shapes are shown in <FIG> shows tube clamping type plates with flat tabs. <FIG> illustrates angled plates which may form a wedge. <FIG> illustrates plates that form a ring. <FIG> shows that plates may have multiple bends or angles as does <FIG>. Various embodiments of the non-modal interplate microwave applicator may be formed to any shape that allows a load to be positioned between the plates and microwave energy to be applied as desired to the load. As mentioned above with respect to <FIG>, the distance between the plates does not need to be uniform as illustrated in <FIG>.

<FIG> illustrate the principle that the plates may also include discontinuities or apertures. For example, <FIG> illustrates that a plate <NUM> may comprise a rectangular wire mesh. <FIG> illustrates a plate <NUM> that includes a regular pattern of holes or apertures. <FIG> illustrates a plate <NUM> that includes an irregular pattern or apertures <NUM> which may be a single aperture or a plurality of apertures. A similar variety of plate shapes and apertures may be included in any other of the embodiments described herein.

<FIG> illustrates a non-modal interplate microwave applicator <NUM>. <FIG> shows a vertical section through a microwave applicator <NUM>. The microwave applicator has a cylindrical nonresonant enclosure <NUM>. The load <NUM> to be treated is placed on a load holder <NUM>. The load holder <NUM> is held in place by a supporting structure <NUM> and <NUM> preferably made of a microwave transparent material such as PTFE. The supporting structure is also holding the applicator plates <NUM> and <NUM> in place. The microwave source <NUM> is connected to the applicator through transmission lines <NUM>, <NUM>, <NUM> and <NUM>. The transmission lines are guided through the enclosure via connectors <NUM> and <NUM>. A tuning device <NUM> is attached to the applicator through transmission lines <NUM>, <NUM>, <NUM>, <NUM> and connectors <NUM> and <NUM>. A microwave tight shield <NUM> and <NUM> may be included to prevent the transmission lines and the tuning device from radiating any microwaves to the surroundings. The microwave heating system <NUM> can be equipped with metallic lids attached to both ends of the nonresonant enclosure forming a pressure tight compartment inside the enclosure.

<FIG> shows a cross sectional view of a non-modal interplate microwave applicator <NUM> that includes a flow reactor <NUM> positioned between plates <NUM> and <NUM> of the non-modal interplate microwave applicator. The flow reactor <NUM> can be made of any suitable material. For example if flow reactor <NUM> is made of a microwave transparent material such as glass or PTFE, then the load will be heated directly by the microwave energy. If the flow reactor <NUM>, i.e. load holder, is made of a microwave absorbent material, then the load may also be indirectly heated by the heating of the load holder, e.g. flow reactor <NUM>. The flow reactor <NUM> is held by a supporting structure <NUM> and <NUM> which also holds the applicator plates <NUM> and <NUM> in a fixed position. The supporting structure <NUM>, <NUM> and the flow reactor <NUM> are surrounded by the nonresonant enclosure <NUM>.

<FIG> illustrates a top-down view of nonresonant interplate microwave applicator <NUM>. Certain elements described and illustrated in <FIG> are not showing in <FIG> in order to illustrate detail from the top-down view. For example, top plate <NUM>, microwave source <NUM>, connectors <NUM>,<NUM> and transmission line <NUM> are shown and described in <FIG> and are not shown again in <FIG>. The nonresonant enclosure <NUM> is made of a conducting material and closed in both ends with metallic lids <NUM> and <NUM> as shown in <FIG>. The flow reactor extends through the lids on each side and is terminated with an end piece <NUM> and <NUM> at each end. The end pieces have a tubing connection <NUM>, <NUM> for connecting a tube at each side of the flow reactor. The tubes are in fluid connection with the flow reactor. By attaching a pump to one end of the flow reactor and a collection vessel at the other end a reaction mixture (load) can be pumped through the reactor and thereby exposed to microwaves. The temperature of the reaction mixture can be measured by a temperature measuring device inserted into the flow reactor or by using an infrared pyrometer <NUM> measuring the temperature on the surface of the flow reactor. The flow reactor <NUM> can be designed to withstand extreme high pressures from <NUM> MPa to <NUM> MPa or more. The flow can be continuous or intermittent in the system.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising <NUM> capillary tubes in a nonresonant enclosure <NUM>. <FIG> shows a view of the microwave heating system <NUM> without the lid <NUM>. <FIG> shows a microwave heating system comprising capillary tubes <NUM> as flow reactors. The capillaries are held in position by a supporting structure <NUM>, <NUM> made of a microwave transparent material. The applicator plates <NUM>, <NUM> are also held in position by the supporting structure <NUM> and <NUM>. The microwaves are fed to the applicator through the connectors <NUM>, <NUM> and transmission lines <NUM>, <NUM> which are connected to the microwave source <NUM>. The whole structure is surrounded by a nonresonant enclosure <NUM>. The enclosure <NUM> is closed at each end with metallic lids <NUM>, <NUM> to prevent the microwaves from propagating outside the enclosure.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising two pairs of applicator plates <NUM>, <NUM> and <NUM>, <NUM>. The two systems are fed from two separate microwave sources <NUM> and <NUM>. The load to be treated <NUM> can be contained in a reaction vessel <NUM> permanently or replaceable mounted in the nonresonant enclosure <NUM>. The reaction vessel can be a flow reactor for treating flowing loads like reaction mixtures. The two pairs of applicator plates are mounted <NUM>° rotated relative to each other. It should be noted that the rotation can be made to any angle and the geometric form of the plates can be other than shown in <FIG>. The plates are fed via transmission lines <NUM>, <NUM> and <NUM>, <NUM> and through the connectors <NUM>, <NUM> and <NUM>, <NUM>. The nonresonant enclosure is closed in each end with metallic lids (see <FIG>). In case of a flow reactor, the lid has openings for the flow reactor tube to extend outside the lids.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising an openable nonresonant enclosure <NUM> and <NUM>. The two halves are held together by a hinge <NUM>. The open structure makes it easy and convenient to insert and extract the load and the load holder to and from the system. The load <NUM> can be contained in a consumable type of load holder for one time use where the treated matter is inserted into an ampoule <NUM> or similar structure. The system <NUM> can also be used when a long structure such as a long flow reactor is to be heated and it is not possible, or inconvenient, to mount the reactor without opening the system <NUM>. The reaction vessel <NUM> is held in place by a holding structure <NUM> which also holds the lower applicator plate <NUM> in place. The upper applicator plate <NUM> is held in place by the structure <NUM>, <NUM>. The transmission line <NUM> is made as a flexible component <NUM> in order to make it possible to open the upper part of the nonresonant enclosure <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. The nonresonant enclosure is formed by the two enclosure halves <NUM> and <NUM> in closed position and closed at each end with metallic lids (see <FIG>). In case of a flow cell, the lid has openings for the tube to extend outside the lids.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a cylindrical applicator with an inner cylinder <NUM> and an outer cylinder <NUM>. The load to be treated is contained in a reaction vessel consisting of an outer cylindrical member <NUM> and a lid <NUM> and <NUM> attached to each end of the cylindrical member <NUM>. The cylindrical member <NUM> is made of microwave transparent materials such as glass or PTFE. The lids <NUM> and <NUM> can be made of any suitable material. The outer cylindrical applicator part <NUM> can be either a separated component or an integrated part of the cylindrical member <NUM>. The outer cylinder <NUM> can typically be integrated with <NUM> through metal deposition on the surface of the cylindrical part <NUM>. The inner cylinder <NUM> can be made of a metallic material with a protecting layer <NUM> of the surface. The protecting layer is made of a microwave transparent material and chemical resistant to the solvent used in the applied treatment process. To feed the reaction vessel with reaction mixture (load) <NUM>, both lids <NUM> and <NUM> have openings <NUM> and <NUM> to be used as an inlet on one side and an outlet on the other side. A reaction mixture can be pumped through the reaction vessel. When both openings <NUM> and <NUM> are closed the system <NUM> can be used as a batch reactor with a stationary load <NUM> in the reaction vessel. The reaction vessel is surrounded by a nonresonant enclosure <NUM> to create appropriate boundary conditions to contain the electromagnetic field within the enclosure <NUM>. The microwaves are fed from the microwave source <NUM> to the cylindrical applicators through the transmission lines <NUM> and <NUM> and through the connector <NUM>. A tuning device <NUM> can be attached to the system <NUM> between the microwave source <NUM> and the outer cylinder <NUM>. The space between the enclosure and the reaction vessel can be pressurized to balance an internal over pressure inside the reaction vessel. The internal pressure in the reaction mixture can either be generated from the chemical reaction itself or by adding a restrictor in a flowing system to generate the internal pressure.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a cylindrical applicator with an inner cylinder <NUM> and an outer cylinder <NUM>. The load to be treated <NUM> is contained in a reaction vessel <NUM> placed in the compartment consisting of an outer cylindrical member <NUM> and a lid <NUM> and <NUM> attached to each end of the cylindrical member <NUM>. The cylindrical member <NUM> is made of microwave transparent materials such as glass or PTFE. The lids <NUM> and <NUM> can be made of any suitable material. The reaction vessel <NUM> is made of a microwave transparent material. The outer cylindrical applicator part <NUM> can be either a separated component or an integrated part of the cylindrical member <NUM>. The outer cylinder <NUM> can typically be integrated with <NUM> through metal deposition on the surface of the cylindrical part <NUM>. The inner cylinder <NUM> can be made of a metallic material with a protecting layer <NUM> of the surface. The protecting layer is made of a microwave transparent material and chemical resistant to the solvent used in the applied treatment process. The reaction vessel <NUM> with reaction mixture (load) <NUM> is placed inside the outer cylinder <NUM> by removing either the upper lid <NUM> or the lower lid <NUM>. The reaction vessel <NUM> is filled with reaction mixture <NUM> before inserted into the outer cylinder <NUM>. Both lids <NUM> and <NUM> have an opening <NUM> and <NUM> to be used as inlet and outlet cooling media, inert gas or to pressurize the environment inside the nonresonant enclosure <NUM>. The reaction vessel is surrounded by a nonresonant enclosure <NUM> to create appropriate boundary conditions to contain the electromagnetic field within the enclosure <NUM>. The microwaves are fed from the microwave source <NUM> to the outer cylindrical applicator member through the transmission line <NUM>. A tuning device <NUM> can be attached to the system <NUM> between the microwave source <NUM> and the outer cylinder <NUM> or between the inner cylinder and ground connection via transmission line <NUM>. The space between the enclosure and the reaction vessel can be pressurized to balance an internal over pressure inside the reaction vessel. The internal pressure in the reaction mixture can be generated from the chemical reaction.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a holder <NUM> and <NUM> for a micro titer plate <NUM> or a similar array structure. The micro titer plate comprises the load <NUM> to be treated. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. The nonresonant enclosure <NUM> is closed at each end with metallic lids (see <FIG>).

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a holder <NUM> and <NUM> for a micro titer plate <NUM> or a similar array structure enclosed in non resonant enclosure <NUM>. The micro titer plate is containing the load <NUM> to be treated. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. The nonresonant enclosure <NUM> is closed at each end with metallic lids (see <FIG>). The system <NUM> has a monitoring system containing an array of transmitters <NUM> and a similar array of receivers <NUM> mounted in the opposite side of the micro titer plate. The transmitter can transmit any type of electromagnetic signal such as ultra violet, infra red, x-ray, laser, etc., and the receiver can be any type of detector detecting the transmitted signal. The transmitter and receiver are connected to a control unit <NUM> through a signal line <NUM> and <NUM>. The control unit either evaluates the signals or just transmits them to a computer via connection <NUM> for further calculations. The signal can be used to monitor and/or control a chemical reaction or a diagnostic process.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system with mechanically adjustable applicator plates <NUM> and <NUM>. By adjusting the plates the impedance matching can be changed for the applicator and thereby tuned to achieve optimal heating conditions. The load <NUM> to be treated is attached to a load holder <NUM> which can be a microscope slide. The load holder is held in position by a holding structure <NUM> and <NUM>. The applicator plates are individually adjustable by rotating the combined belt pulley and drive pulley <NUM> and <NUM>. By rotating the pulley the nut will force the threaded shaft <NUM> and <NUM> to move the applicator plate up or down relative to the load and the other applicator plate. The pulley is rotated through a timing belt <NUM> and <NUM> connected to drive nuts <NUM> and <NUM> driven by motor <NUM> and <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. The nonresonant enclosure <NUM> is closed at each end with metallic lids (see <FIG>).

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> show a microwave heating system comprising an array of applicator plates <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, <NUM>, <NUM>, and <NUM>. The load <NUM>, <NUM>, <NUM>, and <NUM> to be treated is placed between each pair of applicator plates. A nonresonant enclosure <NUM> is surrounding all applicator plates. The microwaves are fed from the microwave source <NUM> to the applicator plates through the transmission lines <NUM>, <NUM>.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a holder <NUM> for tissue samples <NUM>. The holder <NUM> is submerged into a vessel <NUM> filled with a tissue treatment liquid <NUM>. The tissue holding structure <NUM> has openings <NUM> in the structure to allow the treatment liquid to freely pass through the structure and circulate around the tissue samples. The holding structure and the vessel are made of any microwave transparent material. The vessel can be equipped with an inlet and outlet opening at the bottom to make it possible to fill and drain the vessel automatically with a pump system. The pump system can also be used for circulation of the liquid in the vessel. The vessel and the applicator plates are held in position by a holding structure <NUM> and <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. The nonresonant enclosure is closed at each end with metallic lids (see <FIG>).

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a plurality of applicators in the same system. The number of applicators can be repeated many times and be run one at a time, in series or in parallel. It shall be noted that any of the described applicators and systems can be configured with a plurality of applicators as described in <FIG>. The system <NUM> comprises n channels each having a pair of applicator plates <NUM>, <NUM> where the applicator plates are an integrated part of a glass slab <NUM>, <NUM>. The glass slab can for example be a microscope slide. The sample <NUM> is placed on one of the glass slabs. The two glass slabs are separated by two spacers <NUM>, <NUM> and thereby creating a small compartment containing the load. Another spacer can be placed perpendicular to <NUM> and <NUM> and at the bottom and top of the compartment and thereby creating a closed compartment which can be filled with a liquid or gas. The liquid or gas can be a reagent aiming at treating the load <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. A tuning device <NUM> can be added to each applicator. The nonresonant enclosure <NUM> is closed at each end with metallic lids (see <FIG>).

It also should be noted that the various metallic structures described herein may be formed of any type of metal or a composite thereof. For example, metals such as copper, aluminum, brass, steel, etc. or combinations or composites thereof may be used.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a plurality of applicators in the same system. The system of <FIG> uses one microwave source <NUM> and a distributing system <NUM> that distributes the power equally to the number of applicators used or on a time sharing basis where a switching device delivers a predetermined portion of a total time cycle to each applicator. The number of applicators can be repeated many times and be run one at a time, in series or in parallel. It shall be noted that any of the described applicators and systems can be configured with a plurality of applicators as described in <FIG>. The system <NUM> comprises n channels each having a pair of applicator plates <NUM>, <NUM> where the applicator plates are an integrated part of a glass slab <NUM>, <NUM>. The glass slab can for example be a microscope slide. The sample <NUM> is placed on one of the glass slabs. The two glass slabs are separated by two spacers <NUM>, <NUM> and thereby creating a small compartment containing the load. Another spacer can be placed perpendicular to <NUM> and <NUM> and at the bottom and top of the compartment and thereby creating a closed compartment which can be filled with a liquid or gas. The liquid or gas can be a reagent aiming at treating the load <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>, <NUM> and through the connectors <NUM> and <NUM>. A tuning device <NUM> can be added to each applicator. The nonresonant enclosure <NUM> is closed at each end with metallic lids (see <FIG>).

<FIG> shows a system block diagram of a microwave heating system <NUM> that includes a controller <NUM> that can control the tuning devices <NUM> and <NUM> described herein to optimize the performance of the heating systems described herein. The control system <NUM> is controlled by control signals from, for example, a number of sensors and measuring devices in the system as described herein. This signal can be, for example, temperature, pressure, reflected power, etc. The controller <NUM> can be, for example, a finite state machine or a feedback machine. The tuning devices can <NUM> and <NUM> can be placed either between the microwave source <NUM> and the applicator <NUM> or/and after the applicator <NUM>.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. The microwave heating system <NUM> includes a nonresonant enclosure <NUM> constructed of metal and having an applicator consisting of the two applicator plates <NUM> and <NUM> therein surrounding a supporting structure <NUM>. However, the nonresonant enclosure <NUM> may have any shape or size that fulfills the conditions for a nonresonant structure. <FIG> shows a cross-section of such a heating system <NUM>. <FIG> shows a view from the left without the lid <NUM> on.

A metallic lid <NUM> is provided to close the nonresonant enclosure <NUM>. The metallic lid <NUM> may provide a pressure tight seal. In this embodiment, the object to be treated with microwaves, namely the load <NUM> is placed on a holding structure <NUM> that can be a glass slab. It should be noted that the slab may be made of any material. Moreover, the load <NUM> can be of any shape or size, for example, a shape and size that fits into or onto the holding structure <NUM>. The supporting structure <NUM> may be formed, for to receive the holding structure <NUM>. The holding structure <NUM> can be, for example, a pre-made cassette and may have features such as built in channels for liquid flow with flow ports <NUM> and <NUM> that can be used to enable fluids to flow in and out. Further devices like valves, pumps, etc. may be included as an integrated part of the holding structure. The cassette can be made for diagnostic, analytical or preparative purposes. The devices <NUM> and <NUM> can be any type of monitoring devices measuring or monitoring process parameters such as temperature, pressure, light scattering, etc. The devices <NUM> and <NUM> can be arranged in a way such that one is a transmitter and one is a receiver. The transmitter may send a signal that reflects, transmits, scatters, refracts or in any other way is affected by the load and the receiver receives the affected signal from the transmitter. The signals from both devices <NUM> and <NUM> can, for example, be compared using any computational device and an algorithm to calculate a result. The result can be used to control the microwave heating system or generate an output signal used for diagnostic or analytic purposes. The transmitter and receiver can be in the same physical enclosure and need only access from one side of the load <NUM>. The transmitted signal can be radiation of any type, for example, laser, Ultraviolet (UV), Infra Red (IR), x-ray, ultrasound, etc. The receiver can be any type of device that detects, for example the change in the transmitted signal caused by the microwave treatment of the load. The supporting structure <NUM> has an opening <NUM> to gain access to the load for the devices <NUM> and <NUM>. The devices <NUM> and <NUM> can be extended to form an array. Also, the supporting structure <NUM> can be filled with a liquid <NUM> such that the load <NUM> is submerged or partially submerged in the liquid. It should be noted that the liquid can be part of a reaction system where the liquid contains the reactant, catalyst etc. The liquid can be exchanged for a gas. A temperature measuring device <NUM> can be introduced to measure the temperature in or on the load <NUM>. The load <NUM> and the holding structure <NUM> can be, for example, a pre-made cassette with built in channels for liquid flow and functions like valves, pumps etc as an integrated part of the holding structure <NUM>. The cassette can be made for diagnostic, analytical or preparative purposes. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM>.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a coiled capillary flow reactor in a nonresonant enclosure <NUM>. <FIG> shows a view of the microwave heating system <NUM> without the lid <NUM> and the supporting structure <NUM>. <FIG> shows a microwave heating system comprising a coiled capillary tube <NUM> formed as a flow reactor. The flow reactors are held in position by a supporting structure <NUM>, <NUM> made of a microwave transparent material. The applicator plates <NUM>, <NUM> are also held in position by the supporting structure <NUM> and <NUM>. The microwaves are fed to the applicator through the connectors <NUM>, <NUM> and transmission lines <NUM>, <NUM> which are connected to the microwave source <NUM>. The whole structure is surrounded by a nonresonant enclosure <NUM>. The enclosure <NUM> is closed at each end with metallic lids <NUM> and <NUM> to prevent the microwaves from propagating outside the enclosure. A temperature, e.g. IR-sensor, measuring device <NUM> is used to monitor and control the temperature in the flow reactor. <FIG> shows other types of flow reactors that could be used in the system <NUM>. It should be noted that the inner diameter of the flow reactor can be from a few micrometer to several centimeters or more.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a heating system comprising a micro structure. <FIG> showing the main functions of the microstructure. <FIG> shows the flow path in the microstructure <NUM> having an inlet section with three inlet ports <NUM>, <NUM> and <NUM> also designated I3, I2 and I1. The three inlet ports are connected to a mixing chamber <NUM> for mixing the liquids fed to the inlet ports. The mixing chamber <NUM> is connected to a heating portion <NUM> of the microstructure where the mixed liquids are exposed to microwaves. The heating portion is connected to a separation/purification portion <NUM> where the processed reaction mixture is separated or purified using technologies such as chromatography, electrophoresis, phase separation etc. The separated mixture is then fed to an analysis cell <NUM> carrying out any type of analysis on the processed liquid. The analysis cell is connected to an output portion <NUM> of the microstructure. <FIG> shows a section through the micro structure <NUM> containing the flow channels <NUM> manufactured in the substrate <NUM>. The channels are closed by bonding a second substrate <NUM> to the first substrate <NUM>. The applicator plates <NUM> and <NUM> can be either separate components made of a conducting material or as an integrated part of the two substrates <NUM> and <NUM>. The microwaves are fed from the microwave source <NUM> to the applicator plates <NUM> and <NUM> through the transmission lines <NUM> and <NUM> and connectors <NUM> and <NUM>. The microstructure <NUM> is held in place by a holding structure <NUM> and <NUM>. The microstructure <NUM> is surrounded by a nonresonant enclosure <NUM>. It should be noted that the described microstructure is just an example and any type of micro or nano structure can be used in the microwave heating system <NUM>. It shall also be noted that the microwave heating is not limited to one process and can be used to enhance all processes used on a micro structure. These types of applications are often referred to as "lab-on-a-chip" structures.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a microwave heating system comprising a cylindrical applicator similar to the applicator described in <FIG> and <FIG>. Referring to <FIG> showing a microwave heating system comprising a cylindrical applicator with an inner cylinder <NUM> and an outer cylinder <NUM>. The load <NUM> to be treated is contained in a basket <NUM>. The basket is placed in a reaction vessel consisting of an outer cylindrical member <NUM> and a lid <NUM> and <NUM> attached to each end of the cylindrical member <NUM>. The cylindrical member <NUM> is made of microwave transparent materials such as glass or PTFE. The lids <NUM> and <NUM> can be made of any suitable material. The outer cylindrical applicator part <NUM> can be either a separated component or an integrated part of the cylindrical member <NUM>. The outer cylinder <NUM> can typically be integrated with <NUM> through metal deposition on the surface of the cylindrical part <NUM>. The inner cylinder <NUM> can be made of a metallic material with a protecting layer <NUM> of the surface. The protecting layer is made of a microwave transparent material and chemical resistant to the solvent used in the applied treatment process. To feed the reaction vessel with liquid the lids <NUM> have two opening <NUM> and <NUM> to be used as inlet and outlet for the liquid. Liquids can be pumped through the reaction vessel. When both openings <NUM> and <NUM> are closed the system <NUM> can be used as a batch reactor with a stationary load <NUM> in the reaction vessel. The reaction vessel is surrounded by a nonresonant enclosure <NUM> to create appropriate boundary conditions to contain the electromagnetic field within the enclosure <NUM>. The microwaves are fed from the microwave source <NUM> to the cylindrical applicators through the transmission lines <NUM> and <NUM> and through the connector <NUM>. A tuning device <NUM> can be attached to the system <NUM> between the microwave source <NUM> and the outer cylinder <NUM>. The space between the enclosure and the reaction vessel can be pressurized to balance an internal over pressure inside the reaction vessel. The internal over pressure can be generated to increase the boiling point of the used liquid to enhance the treatment of the load. A typical example of process in the described microwave heating system <NUM> is pre-treatment of tissue for diagnostic purposes.

Tissue samples in tissue block containers may also be processed using embodiments of a non-modal interpolate microwave applicator as described with respect to <FIG> or other similar figures. With microwave tissue processing, tissues are dehydrated and infused with embedding media such as paraffin in order to preserve the tissues. Application of heat using a non-modal interpolate microwave applicator may speed up or otherwise enhance the tissue process.

<FIG> illustrates a multiple load interleaved plate non-modal interplate microwave applicator <NUM>. By interleaving two sets of plates, a balanced non-modal interplate microwave applicator can be constructed that may be beneficial in provide a compact, balanced, symmetrical microwave heater for multiple samples. Microwave source <NUM> connects on one side through transmission line <NUM> in parallel to plates <NUM> and on another side microwave source <NUM> connects through transmission line <NUM> in parallel to plates <NUM>. A load holder <NUM> with a load, e.g. a tissue specimen <NUM> is positioned between each set of place <NUM>, <NUM>. Thus, a very compact microwave heater that is relatively uncomplicated to construct and operated while at the same time is capable of processing a number of loads in parallel may be achieved.

In another example, a microwave heating system <NUM> as shown in <FIG> may be provided. <FIG> shows a heating system comprising a batch reactor <NUM> that is placed between the applicator plates <NUM> and <NUM>. The batch reactor contains the reaction mixture to be microwave treated. The batch reactor can be made of any microwave transparent material such as glass or PTFE. The batch reactor is held by a supporting structure <NUM> and <NUM> which also holds the applicator plates <NUM> and <NUM> in a fixed position. The supporting structure and the batch reactor are surrounded by the nonresonant enclosure <NUM>. The nonresonant enclosure is made of a conducting material and closed in both ends with metallic lids <NUM> and <NUM>. The batch reactor extends through the lid <NUM> on one side and is terminated with an end piece <NUM>. The temperature of the reaction mixture can be measured by a temperature measuring device inserted into the reactor or by using an infra red pyrometer <NUM> measuring the temperature on the surface of the batch reactor. The batch reactor <NUM> can be designed to withstand extreme high pressures from <NUM> MPa to <NUM> MPa or more. The end piece <NUM> can hold a pressure measuring device that can be electrical connected to a control system by cable <NUM>. The end piece can also contain several ports <NUM> as inlet or outlet of liquids or gases to the reaction vessel. The port can have valves <NUM> to close or open the access to the reaction vial. This can be used for adding reagents during a reaction or sampling of the reaction mixture to perform any type of analysis of the subtracted liquid or gas.

<FIG> illustrates a front view of a microwave heating system <NUM> having a non-modal interplate microwave applicator surrounding a load. Microwave heating system <NUM> includes a nonresonant enclosure <NUM> In one prototype embodiment, nonresonant enclosure <NUM> is a metal enclosure and comprises a metal top end piece <NUM> and a metal bottom end piece <NUM> with removable metal walls on four sides.

A sensor opening <NUM> is provided for a temperature sensor which in the prototype embodiment was an infrared temperature sensor. The opening enables temperature measurements to be made without affecting the microwave field during operation. Enclosure <NUM> includes a sample opening <NUM> that enables a sample to be inserted and / or removed. A microwave source (not shown) may be connected to coaxial connector <NUM>.

<FIG> illustrates a sample rack <NUM> with a holder <NUM> that is adapted to hold a sample carrier <NUM>, e.g. a microscope slide comprising a sample <NUM>. The sample rack <NUM> may be inserted into sample opening <NUM> shown in <FIG> to position the sample to be heated. Sample rack <NUM> is depicted carrying a single sample carrier, e.g. microscope slide, but alternative embodiments may include multiple racks each with one sample carrier or one rack with multiple sample carriers. In embodiments adapted to accommodate multiple sample carriers in one or more racks, appropriate modification of the plate size, enclosure size, connectors, etc., may be may to accommodate the desired configuration. The vertical endpiece of slide holder <NUM> is arranged perpendicular to the slide and acts to prevent microwave leakage by electromagnetically sealing opening <NUM> shown in <FIG> when slide holder <NUM> is inserted.

<FIG> depicts a back view of the microwave heating system <NUM> which is shown In <FIG> from a front view. In <FIG>, one of the enclosure walls which would be normally screwed down has been removed in order to show the various internal components. The distance between top plate holder <NUM> and bottom plate holder <NUM> may be adjusted by turning adjuster knob <NUM> which turns screw <NUM> to cause one of threaded plate holders <NUM> and <NUM> to move up or down upon the threads of screw <NUM>.

A microwave applicator comprises top plate <NUM> and bottom plate <NUM>. Top plate <NUM> connects to one terminal of connector <NUM> and a bottom plate <NUM> connects coaxial connector <NUM> which connects in turn to the other terminal of connector <NUM>. A microwave source may connect to connector <NUM> to provide microwave energy for the applicator. Sample holder <NUM> that holds a sample carrier <NUM> carrying a sample <NUM> may be inserted between plates <NUM> and <NUM>.

Certain features of <FIG>, <FIG> and <FIG> are adapted to facilitate prototype usage. However similar features such as adjustable plate distances, temperature sensor opening <NUM> and removable walls of enclosure <NUM> may also be included in any combination or arrangement for any desired embodiment of non-modal interplate microwave heating system.

Claim 1:
A slide staining system (<NUM>) comprising a microwave heating system, said microwave heating system comprising:
a non-modal interplate microwave applicator (<NUM>, <NUM>) comprising at least two applicator plates (<NUM>, <NUM>, <NUM>, <NUM>) configured to receive a biological sample on a microscope slide to be heated by microwaves radiated with a wavelength λ from the applicator between the plates, wherein the microwave applicator is configured to generate an electromagnetic field between the applicator plates for applying microwave energy to the biological sample on the microscope slide, wherein the strength of the electric field at the biological sample on the microscope slide does not depend on standing wave modes and wherein the at least two applicator plates are separated with a distance d that is λ/<NUM> or less; and
a microwave source (<NUM>) connected to the non-modal interplate microwave applicator.