Patent Description:
Many biological liquids (for example blood, urine) are complex mixtures of many different components. There is often a need to be able to separate these components to perform analysis on the liquid (for example in a diagnostic test) to void some parts of the liquid interfering with the analysis.

For example, a common requirement is to be able to separate a whole blood sample into its liquid plasma component separated from the cellular matter of the blood (red and white blood cells). The vast majority of analytical blood tests actually require the liquid plasma to be used as the input sample material as the cellular matter can interfere with many analytical tests. This is normally accomplished using centrifugation. The sample is spun at high speed in a bench-top laboratory centrifuge which separates the blood into components according to their relative densities with the lighter liquid plasma remaining on top of the tube after spinning and available to be aspirated off.

In order to generate the centrifugal force necessary to achieve separation of the blood, the sample is spun some distance away from an axis at high speed. This is often achieved by using sample tubes placed <NUM>-<NUM> away from the rotational axis and at an angle of <NUM>-45deg from the vertical. The angled tubes help to maintain the plasma and blood separation as the centrifuge comes to a stop.

As the sample is placed at an angle in a traditional centrifuge, the process of loading and unloading the sample requires some level of complexity to avoid spilling or remixing the sample. Therefore, such centrifuges either require significant manual intervention to load and unload the sample and extract the generated plasma, or a large and complex machine is required to automate this process limiting it to, for example central lab instruments.

However, there is an increasing need to be able to generate plasma samples outside of a laboratory. For example, many diagnostic tests developed for use at the point of care would benefit from being able to take a whole blood input and to be able to separate the plasma within a point-of-care test system to actually perform the analytical chemistry with the plasma.

There are a few examples in the prior art that attempt to meet this challenge:
The first is the use of a separation filter instead of centrifugation to separate the blood from plasma. For example, the Pall Vivid Membrane. This works by size filtration, trapping the cells that are too large to pass through the filter. However, this approach is slow, relying on capillary action to wick the sample through the membrane, inefficient with only a maximum of typically <NUM>% of available plasma extracted, prone to contamination as the filter can cause cells to lyse releasing harmful cell contents into the plasma, and filters can typically only process up to ~100uL of blood sample input before they get clogged with cells.

A second example is the use of a micro-fluidic centrifugal disc where the entire fluidic system is built on a rotating platform that includes specific elements to separate a blood sample into plasma in the same device. However, this restricts its use to those workflows that can be built into a rotating fluidic disc and the maximum volumes are again limited to those that can easily be accommodated on micro-fluidic discs, typically of the order of 100uL.

The current art is missing a device that is suitable for separating larger volumes (>500ul) of blood into plasma in a way that could be integrated into a simple fluidic cartridge for use at the point of care.

<CIT> describes a method for rapid separation of serum or plasma from cells in a whole blood sample uses a cylindrical sample tube having longitudinally-extending internal ribs. A separation gel and the sample are introduced into the tube, and the tube is axially centrifuged so as to form concentric shells of cells, gel, and serum or plasma.

After centrifugation is stopped, the serum or plasma collects in the tube by gravity flow and the cells and gel remain affixed to the walls and ribs of the tube.

<CIT> describes a centrifuge for separating the plasma and red cells of blood into segregated constituent volumes, comprising a vessel rotatable about a vertical axis to perform a centrifuging operation and having defined at the bottom thereof a central well and a trough disposed radially outwardly thereof, said well having an outer periphery defining the inner side wall of said trough, said trough having an open upper end at the periphery of the well and the latter being inclined downwardly from its periphery to the axis of rotation, whereby, with said trough having a capacity not less than the separate constituent red cell volume in a predetermined volume of blood received in said vessel for centrifuging but less than said predetermined volume of blood, said trough, upon completion of the centrifuging operation, will contain all of the said separate constituent red cell volume of said predetermined volume of blood, said vessel having a bottom wall provided with said well and an outer side wall extending upwardly therefrom, said outer side wall being conical and converging upwardly from said bottom wall and forming the outer: wall of said trough, said inner side wall of the trough converging upwardly from said bottom and the upper surface of said well being dish-shaped and terminating at the top of said inner side wall of said trough, said outer side wall of the trough extending upwardly beyond the top of said inner wall.

<CIT> considers the problem of how to enable recovering centrifuged ingredients of an analyte efficiently. In a container for centrifugal separation used in a method of separating centrifugally ingredients of an analyte by rotating the container with the central axis of the container as the rotational axis, a storage part forming a storage space includes a trap part which forms a trap space of a capacity capable of storing a high-specific-gravity ingredient when the analyte is centrifuged to form a layer structure on the outer peripheral side of the storage space, an inclined inner wall part which decreases gradually in diameter and connects the portion from the trap part to the bottom part, and a guide part which is provided at a position crossing the area where the layer structure is to be formed so as to be directed from the trap part toward the inclined inner wall part in order to guide low-specific-gravity ingredients in the layer structure flowing under the inertial force produced by deceleration of rotation to the inclined inner wall part.

<CIT> describes an analyzer, preferably a desktop analyzer, that includes: a component transport system; a liquid dispense or aspirating station; a member removably located on the transport system. The removable holder includes: a probe tip dispenser; a fluid supply section for holding a sample; a test element recess for holding one or more test elements or test element holders, wherein the removable holder is configured to contain the test element recess such that a test element can be acted upon by the liquid dispense or aspirating station, while the test element is in the recess; and a measurement device to analyze a sample. Also described is a removable centrifuge model on the transport system, which separates samples, such as whole blood before analysis.

<CIT> describes a device for separating materials of different densities. A cup body has an internal cavity configured to hold media. An inner wall defines a central body region having an upper and lower end. The upper end is wider than the lower end. An interior shoulder circumscribes the upper end of the central body region. The interior shoulder defines a neck region above the central body region and a shoulder trap below the neck region. The shoulder trap circumscribes the upper end of the central body region and is wider than the neck region. When the device is spun about a central axis, the media travels upward along the inner wall toward the shoulder trap. Relatively more dense material in the media is collected in the shoulder trap, and relatively less dense material is expelled from the device through an opening above the neck region. Further described is an apparatus for separating media and a method for separating media using the separating device.

The present disclosure provides a solution using a pot which is adapted to allow centrifugation to take place by spinning the pot about its own axis, thus negating the need for any complex movements or rotations during the process. The simplicity afforded by this design allows for the integration of this pot into a disposable cartridge suitable for use in point of care workflows.

According to a first aspect, the present disclosure provides a consumable cartridge as set out in claim <NUM>.

Optionally, the pot is adapted to be spun on the central axis for centrifugal separation of the biological fluid in the inner volume, wherein the multiple components remain separated once the pot ceases to spin.

Optionally, each of the plurality of baffles does not protrude as far as a centre of the pot, and extends along the wall for between half of and all of a distance between the top end and the bottom end.

Optionally, the plurality of baffles are substantially equally spaced around the central axis.

Optionally, the plurality of baffles comprises a first baffle that protrudes from the wall by a first distance and a second baffle that protrudes from the wall by a second distance, the first distance being different from the second distance.

Optionally, the plurality of baffles are each formed as an arc of a curve in a plane defined by the central axis, the curve having a radius between <NUM> and <NUM> of a width of the pot.

Optionally, the protrusion from the bottom end is formed around the central axis with a width of approximately half of a width of the pot, and protrudes between <NUM> and <NUM> from the bottom end.

Optionally, the centrifugal separation separates plasma towards the central axis, and the pot is adapted to enable a component of the biological fluid to be extracted through an opening in the top end.

Optionally, a width of the pot is less than <NUM>.

Optionally, a distance between the top end and the bottom end is less than <NUM>.

Optionally, the pot is adapted to be spun at at least <NUM>,<NUM> RPM.

Optionally, the biological fluid is blood and the multiple components of the biological fluid comprise plasma and cellular matter.

Optionally, the consumable cartridge further comprises a second holding means adapted to securely hold the pot in place until the cartridge is inserted into a centrifuge instrument, and to release the pot to spin freely when the cartridge is inserted into the centrifuge instrument.

Optionally, the cartridge is adapted to hold the pot at least partly within the cartridge body when the pot is spinning at at least <NUM>,<NUM> RPM.

The present disclosure provides a rotatable pot that, when spun along its axis, can effect the separation of the cellular matter from blood via centrifugation. By virtue of the design disclosed here, the cellular matter of the blood remains separated from the liquid portion (plasma) even when the pot comes to a complete stop, or at least decreases a speed of remixing between the separated blood and plasma, thereby extending the time in which it is possible to extract the plasma for analysis. In addition, the design enables the pot to be integrated within a disposable cartridge to allow the inclusion of a centrifugation step within an existing micro- or meso-fluidic workflow.

The design of the pot reduces the complexity normally associated with integrating a centrifugation step within a workflow that could be useful, for instance, at the point of care, and can be performed using smaller, lower cost equipment than would conventionally be available in a large-scale central lab.

<FIG> illustrates a pot comprising a lower part <NUM> and an upper part <NUM>.

The lower part <NUM> comprises a wall <NUM> around a central axis <NUM>, and a bottom end <NUM>, which together define an inner volume that can contain a liquid such as blood.

In this example, the wall has a round, cylindrical shape. However, in other examples, the wall may instead be polygonal, so long as a central axis can be defined.

The upper part <NUM> comprises a top end <NUM> of the pot. In this example, the upper part <NUM> further comprises an opening <NUM> that is a permanently open hole through which contents of the pot may be added or removed. Even in examples where the upper part <NUM> comprises an opening, the upper part <NUM> prevents liquid from spilling out of the pot when it is spun.

Centrifugation of blood separates plasma towards the central axis <NUM> and therefore including the opening <NUM> at or near to the middle of the top end <NUM> enables extraction of separated plasma through the opening <NUM>.

In this example, the upper part <NUM> is manufactured separately from the lower part <NUM>, and acts as a removable lid for the lower part <NUM>. The design of this pot disclosed in this invention can be made using for example, two injection moulded parts. However, the lower part <NUM> and upper part <NUM> may instead be formed together as a unitary pot. The upper and lower parts of the pot may be welded together or, in another example, blow-moulding may be used to create the pot as a single part.

In this example, the lower part <NUM> additionally comprises a plurality of baffles <NUM> protruding from the wall into the inner volume. The baffles may take a variety of shapes, as explained below, but in this example the baffles are scalloped. The scalloped shape of the baffles has the effect of preventing re-mixing of separated blood and plasma when the pot experiences a decelerating force at the end of centrifugation. Alternatively, the baffles may be omitted.

In an example having a volume useful for point-of-care applications, the pot has a radius of less than <NUM> and a height (i.e. a distance between the top end <NUM> and the bottom end <NUM>) of less than <NUM>. The pot may be cylindrical, in which case "radius" takes its normal meaning. However, this is merely the simplest case and the pot may have a less smooth, polygonal, cross-section. In such alternatives, "radius" refers to half of the average width across the polygonal cross-section, and is alternatively called the "half-width" herein. Therefore, the pot may, more generally, usefully have a width of less than <NUM>.

<FIG> provides a plan view of the pot in which the baffles can be more easily seen.

In this example, each of the plurality of baffles <NUM> does not protrude as far as a centre <NUM> of the pot (corresponding to the central axis <NUM>) and extends along the wall (i.e. out of the plane of <FIG>) for between half of and all of the height of the wall (i.e. the distance between the top end <NUM> and the bottom end <NUM>). Additionally, in this example, the plurality of baffles <NUM> are substantially equally spaced around the centre <NUM> (corresponding to the central axis <NUM>).

Additionally, as shown in <FIG>, in this example, the lower part <NUM> comprises a protrusion <NUM> from the bottom end <NUM>. The protrusion <NUM> extends into the inner volume and around the centre <NUM> (corresponding to the central axis <NUM>). Such a protrusion <NUM> may be formed around the central axis <NUM> with a radius of approximately half of the radius of the pot. In other words, in the case of a cylindrical pot as shown in <FIG>, the protrusion <NUM> may take the shape of a circle of about half the radius of the pot. As with the wall <NUM>, the protrusion <NUM> need not be a smooth shape, and may instead be polygonal.

The protrusion <NUM> provides a small inner wall extending from the bottom of the pot. When blood is centrifuged in the pot, this inner wall feature helps to trap separated cellular matter away from the centre <NUM> of the pot, helping to maintain separation of plasma in the centre of the pot for longer after centrifugation. This effect is particularly enhanced in cases where the protrusion <NUM> protrudes between <NUM> and <NUM> from the bottom end.

Since both of the baffles <NUM> and the protrusion <NUM> independently assist in isolating plasma for longer, either the baffles <NUM> or the protrusion <NUM>, or more preferably both, may be included in examples of the invention.

Additionally, as shown in <FIG>, the pot of this example includes one or more outer ribs <NUM> on an external surface of the wall <NUM>. These outer ribs <NUM> can be provided to engage with a rotor of a centrifuge instrument in order to prevent slipping when the rotor is driving rotation of the pot.

Referring now to <FIG>, the principles of centrifugation of blood in the pot will be explained.

When the pot is spun around the central axis <NUM>, the liquid contained therein is centrifuged, which may be used to separate plasma from blood. More specifically, by virtue of the centrifugal forces imparted on the blood by spinning, denser cellular matter <NUM> of the blood migrates away from the central axis <NUM> and less dense plasma material <NUM> migrates towards the central axis <NUM>. This is illustrated in <FIG> which represents a pot spinning <NUM> of blood at <NUM>,<NUM> revolutions per minute (RPM) to give <NUM> of cellular matter <NUM> and <NUM> of plasma <NUM>.

The centrifugal force that the blood is subjected to is a function of the both the radius (rpot - expressed here in millimetres) and angular velocity or rotation speed (ω - expressed here in revolutions per minute) of the pot and is often expressed in terms of a relative centrifugal force FRCF which expresses the force relative to that experienced by a <NUM> mass falling under Earth's gravity: <MAT>.

This means that as the pot radius (or more generally half-width) decreases, a larger rotation speed is required to separate the plasma from the blood. For the devices envisioned by this invention, the pot radius can be as small as, for example, <NUM> - <NUM> which then requires the pot to rotate with an angular velocity of between <NUM>,<NUM> RPM and <NUM>,<NUM> RPM to achieve a relative centrifugal force of between <NUM> - <NUM>,<NUM> which is typically understood to be required to enable separation of blood from plasma.

Accordingly, the pot may be adapted to tolerate being spun at at least <NUM>,<NUM> RPM.

In particular, at these high rotational speeds, it is critical that the pot has a symmetric mass balance about its central axis <NUM> to ensure that there are no significant off-axis mechanical forces generated by the rotation that could damage a centrifuge mechanism with which the pot is used. Automatic mass-balancing may be achieved to a large extent by adapting the pot to be spun on its own central axis <NUM>. As the mass of the blood that is being spun can be of a similar or even greater level than the mass of the pot, the liquid blood will naturally act to compensate for any off-axis or non-symmetric mass distributions in the pot itself. This enables the pot to be made via methods that do not require accurate or precise mass distributions. For example, simple plastic injection moulding would be suitable for manufacturing the pot because any resulting irregularities or non-symmetric mass distributions would be compensated for by the mass of the blood spinning within the pot.

A pot which tolerates high rotational speeds requires that the materials used to construct the pot are of sufficient strength to withstand the centrifugal stresses generated. An example of such a suitable material could be polypropylene or polycarbonate.

<FIG> is a schematic plan view of the pot during rotation corresponding to <FIG>. Arrow <NUM> illustrates a direction of rotation. In examples with scalloped baffles <NUM>, the direction of rotation is chosen such that the baffles <NUM> curve against the direction of motion. This means that, when the pot slows its rotation, the inertia of the contents of the pot directs the contents into the regions <NUM> between the baffles <NUM> and the wall <NUM>.

When a conventional pot decelerates, the effective force acting on the blood changes from horizontal (centrifugal) to vertical (gravity). In theory, this change of effective forces would allow the plasma to be aspirated as, under gravity, the plasma <NUM> comes to rest on top of the denser blood cellular material <NUM>. This conventionally-theoretical result is represented in <FIG>.

However, in practice it is very difficult to achieve a smooth enough deceleration to prevent re-mixing of the blood and plasma as the pot comes to a stop, and therefore the distribution shown in <FIG> is not normally achieved in practice. Further, even if the distribution shown in <FIG> can be achieved, it is difficult to only aspirate the plasma <NUM> from atop the cellular material <NUM> without careful alignment of an aspiration needle.

The pot described herein is adapted to overcome this limitation, and make aspiration of the plasma <NUM> without aspirating the cellular material <NUM> easier and more effective.

More specifically, the inclusion of the baffles <NUM> as shown in <FIG> cause the denser cellular material <NUM>, which has greater inertia than the plasma <NUM>, to collect in the regions <NUM> between the baffles <NUM> and the wall <NUM>. This prevents the cellular material <NUM> from moving radially inward as the pot reduces its rotation speed, and prevents the re-mixing of the separated cellular material <NUM> and plasma <NUM> upon deceleration. Effectively, the baffles <NUM> turn the pot into a series of isolated chambers <NUM>, which helps reduce the ability of shear forces of the wall <NUM> against the cellular material <NUM> to cause re-mixing.

Simultaneously, the protrusion <NUM> prevents cellular material <NUM>, which has collected under gravity at the bottom of the pot, from moving towards the centre <NUM>.

These combined effects lead to the sequence shown in <FIG>, <FIG> and, finally, achieve the distribution of <FIG> in practice. More specifically, <FIG> is a schematic illustration of an example pot when it is slowing down after centrifugation, when it is still rotating at <NUM> RPM, <FIG> is a schematic illustration of the pot just after it has stopped rotating, and the distribution of <FIG> is reached by one minute after the pot has stopped rotating.

More specifically, in <FIG>, it can be seen that the combination of the baffles <NUM> and the protrusion <NUM> has caused the cellular material <NUM> to settle between the protrusion <NUM> and the wall <NUM>. On the other hand, the continuing rotation at this stage means that the surface of the separated plasma <NUM> curves upwards away from the central axis <NUM>.

Then, in <FIG>, when the rotation has stopped the plasma <NUM> settles to have a flat horizontal surface. On the other hand, surface tension at the meeting point between the plasma <NUM>, the cellular material <NUM> and the protrusion <NUM> prevents the cellular material <NUM> from spilling over the protrusion <NUM>. Thus, the cellular material <NUM> remains sloped outside the protrusion <NUM> and the central area inside the protrusion <NUM> contains only plasma <NUM>.

Even with the features of the invention, this situation is only temporary and thus, by one minute after the pot stops rotation, the distribution shown in <FIG> appears due to gravitational effects on the separated plasma <NUM> and cellular material <NUM>.

Due to the protrusion <NUM> and the baffles <NUM>, this settling is delayed substantially until after the pot has stopped rotating, and thus far less re-mixing occurs during the settling making the distribution of <FIG>, wherein the plasma <NUM> remains separated from the cellular material <NUM> once the pot ceases to spin, practically achievable.

Additionally, by providing alternative features to achieve the distribution of <FIG>, even temporarily, the pot of the invention provides an opportunity to aspirate the plasma from the centre <NUM> of the pot without requiring careful alignment of an aspiration means (such as an aspiration needle).

Unlike traditional centrifuges and centrifuge pots, where the containers are spun at an angle with respect to gravity, the above described system enables the pot to be spun on its axis parallel with gravity. This allows for the use of a very simple instrument to carry out the centrifugation and consequently reduces the complexity of the fluidics necessary to collect the generated plasma from the device. The pot does not require rotation about any other axis in order to extract the generated plasma from the top of the pot.

This reduced complexity enables the pot to be used within a simple disposable cartridge as shown, for example, in <FIG>.

<FIG> schematically illustrate a consumable cartridge having a pot as previously described. <FIG> shows the cartridge in an initial fill state where the pot has been filled with <NUM> of blood <NUM>, <NUM>. <FIG> shows the cartridge during centrifugation, wherein the pot is rotating in the cartridge at <NUM>,<NUM> RPM and the blood has separated into cellular material <NUM> and plasma <NUM>.

In particular, <FIG> show a cross-section through the cartridge and through the pot. The cartridge has a cartridge body <NUM> which is cut through in an intended vertical plane of the pot. It can be seen in <FIG> that the cartridge body <NUM> extends on either side of the pot and the cartridge body <NUM>' also extends around behind the pot, such that the cartridge body <NUM>, <NUM>' is adapted to receive the pot at least partly within the cartridge body. However, the pot may also extend beyond the cartridge body <NUM>, <NUM>' as shown at the bottom of <FIG>.

Additionally, the cartridge comprises a dispensing element <NUM> for dispensing blood <NUM>, <NUM> into the pot, and an aspirating element <NUM> for extracting plasma <NUM> from the pot. The dispensing element <NUM> and aspirating element <NUM> may approximately take the form of a needle. The dispensing element <NUM> and aspirating element <NUM> may be attached to the cartridge body <NUM> or may be formed as part of the cartridge body <NUM>. In this example, the dispensing element <NUM> and the aspirating element <NUM> extend through the opening <NUM> in the top end <NUM>, and remain in the pot during centrifugation as shown in <FIG>. More specifically, the aspirating element <NUM> is located on the central axis <NUM> of the pot such that it is appropriately positioned to quickly take advantage of the temporary distribution of plasma <NUM> shown in <FIG>, as explained above. Thus no moving parts are required for the dispensing element <NUM> and the aspirating element <NUM>. Accordingly, it is not necessary to introduce a moving aspirating element after centrifugation, which would conventionally disrupt the separated components and cause some re-mixing. More generally, a cartridge as described herein does not require any moving parts other than the pot, which simplifies construction of the cartridge. In alternative examples, the dispensing element <NUM> and aspirating element <NUM> may be omitted or replaced with moving parts, and the cartridge may only provide a convenient means for holding the pot during rotation.

As further shown in <FIG>, the cartridge also comprises a first holding means <NUM> for holding the pot at least partly within the cartridge body, while allowing the pot to rotate. More specifically, in this example, the first holding means extends with the dispensing element <NUM> and aspirating element <NUM> into the pot through the opening <NUM>. The first holding means has a protrusion which extends radially beyond the opening <NUM> such that the first holding means cannot pass through the opening <NUM>. This means that the pot must remain at least partly within the cartridge body. However, this does not prevent the pot from rotating around the dispensing element <NUM>, aspirating element <NUM> and first holding means <NUM>. In particular, there is sufficient clearance between the protrusion of the first holding means <NUM> and the cartridge body <NUM> to allow rotation of the pot without friction against the cartridge body <NUM> or the clip <NUM>.

The first holding means <NUM> may be provided in the form of a flexible clip comprising a flange that is sloped on one side. This allows for snap fit assembly of the cartridge by sliding the pot over the dispensing element <NUM>, aspirating element <NUM> and first holding means <NUM>. In such cases, the flexible clip must be stiff enough to prevent a reversal of the snap-fit connection due to forces experienced during centrifugation of the pot. The first holding means <NUM> may be attached to the cartridge body <NUM> or may be formed as part of the cartridge body <NUM>.

Optionally, the cartridge may also comprise a second holding means <NUM> adapted to securely hold the pot in place until the cartridge is inserted into a centrifuge instrument for driving rotation of the pot, and adapted to release the pot to spin freely when the cartridge is inserted into the centrifuge instrument.

The second holding means <NUM> may be a flexible clip similar to the first holding means. However, the secure hold of the second holding means <NUM> may be provided by locating the second holding means close to a surface of the cartridge body <NUM>, such that the pot can be secured between the second holding means <NUM> and the cartridge body <NUM>. In such a position, friction between the pot, the cartridge body <NUM> and the second holding means <NUM> may be sufficient to prevent rotation of the pot. Additionally, the second holding means <NUM> may provide a reversible connection, so that the pot can disengage from the second holding means <NUM> to be released to spin freely during centrifugation. The second holding means <NUM> may be attached to the cartridge body <NUM> or may be formed as part of the cartridge body <NUM>.

<FIG> and <FIG> illustrate what happens when the cartridge is inserted into a centrifuge instrument. In particular, <FIG> and <FIG> illustrate the cartridge before and after the pot has been disengaged from the second holding means <NUM>.

As shown in <FIG>, the centrifuge instrument may comprise a rotor <NUM> and first and second cartridge holding means <NUM> and <NUM> for securing the cartridge during centrifugation. The centrifuge instrument and cartridge may also comprise corresponding interfaces for allowing the centrifuge instrument to connect to the dispensing element <NUM> and aspirating element <NUM> of the cartridge. Furthermore, the centrifuge instrument may be part of an integrated diagnostic instrument for both centrifuging blood and analysing the obtained plasma.

The rotor <NUM> may engage with the outer ribs <NUM> of the pot (if present) or may use friction with an outer surface of the pot to drive rotation of the pot during centrifugation.

Additionally, the centrifuge instrument may comprise a disengaging means <NUM> to provide the force to disengage the second holding means <NUM> from the pot (if the second holding means is present). Such a disengaging force may be transmitted through the top end <NUM> of the pot, as shown in <FIG> and <FIG>. This disengaging means <NUM> could be a passive extension which disengages the second holding means <NUM> from the pot when the first and second cartridge holding means <NUM> and <NUM> are secured around the cartridge. Alternatively, the disengaging means <NUM> could be an active linear actuator, controlled to disengage the pot from the second holding means <NUM> only when the centrifuge instrument is ready to perform centrifugation. For example, the disengaging means <NUM> may only be used after the dispensing element <NUM> has filled the pot.

Additional components of a centrifuge instrument that can be used to spin the pot are shown in <FIG>.

The rotor <NUM> may be driven by a brushless DC motor <NUM>. The holding means <NUM> may be part of the instrument housing, and may align the cartridge with the rotor <NUM> and ensure spacing between the cartridge and the spinning rotor, such that the cartridge cannot become misaligned during centrifugation or provide friction against the rotor <NUM>.

In the above description and referenced figures, the pot has been shown to have scalloped baffles <NUM>. As mentioned above, these baffles may be omitted and the invention may instead rely on the protrusion <NUM>. Additionally, the baffles can take a variety of forms and can vary in their number. For example, in one example, the baffles can protrude straight from the wall <NUM> toward the centre <NUM> and be of equal length and height, as shown in <FIG>. In this example, there are six baffles.

The number of radial baffles <NUM> can also be adapted depending on the properties of the liquid being centrifuged within the pot. In general, a pot with more radial baffles will help maintain separation better. For example, the pot of <FIG> has <NUM> baffles. However, as the number of baffles increases, this will reduce the available volume of the pot as well as provide more points for liquid to become trapped, or 'pinned', due to surface tension.

To help overcome this issue, additionally, the baffles <NUM> may comprise a first baffle 114a that protrudes from the wall <NUM> by a first distance and a second baffle 114b that protrudes from the wall by a second distance, the first distance being different from the second distance. The baffles <NUM> may comprise plural of each type of baffle 114a, 114b, as shown in <FIG> and <FIG>. This arrangement enables more of the baffles to protrude further in toward the centre of the pot which helps to prevent remixing of the blood and plasma under deceleration without making the opening from the pot into the baffled zones too small, which might otherwise cause issues with surface tension pinning in pots with small dimensions. The smaller length baffles act to provide more "separated" compartments whilst maintaining an minimum width of opening <NUM> between the baffles large that is enough to prevent pinning via surface tension. In many examples, this means that the baffles do not protrude as far as the centre <NUM>, and protrude from the wall <NUM> by a distance less than a radius fo the pot.

Additionally, more complex baffle arrangements can be used such as shown in <FIG>. In this example, baffles 114a, 114b of different lengths are connected to the protrusion <NUM>. With this example, the "compartments" defined by the baffles may be truly separated from the rest of the inner volume (in a plane perpendicular to the central axis <NUM>) for at least part of the height of the pot, making remixing of cellular matter <NUM> and plasma <NUM> yet slower or even impossible.

The shape of the baffles can also affect how the device performs. In a preferred embodiment described above, the shape of the baffles can be formed as an angled scallop which further helps to keep the blood and plasma separated, as shown in <FIG>.

As mentioned above, upon deceleration, the inertia of the blood against the slowing pot, causes much of the cellular matter to become trapped in the corners <NUM> of the baffles reducing the chance of remixing. This effect is present even with straight baffles, but is amplified with scalloped baffles.

Further detail of a particularly advantageous scalloped baffle embodiment is shown in <FIG>.

In particular, as shown in <FIG> the scalloped baffles are formed as an arc of a curve of a radius <NUM> between <NUM> and <NUM> of the radius of the pot, in a plane defined by the central axis <NUM> (as opposed to curving in a vertical plane). Alternatively, where the pot is polygonal as described above, the scalloped baffles may be formed as an arc of a curve having a radius between <NUM> and <NUM> of a width of the pot.

Additionally, as shown in <FIG>, the scalloped baffles protrude into the inner volume by a distance of between <NUM> and <NUM> of the radius of the pot, as illustrated in <FIG> by the distance <NUM> between the centre <NUM> and the and end of a baffle <NUM>. Alternatively, where the pot is polygonal as described above, the scalloped baffles may protrude into the inner volume by a distance of between <NUM> and <NUM> of the average half-width of the pot.

Other shapes of baffle are also possible. For example, a top or bottom end of a baffle may be horizontal, or may curve in a vertical plane parallel to the central axis <NUM> towards or away from the bottom end <NUM> of the pot, as the baffle <NUM> protrudes away from the wall <NUM>.

Specific examples of baffles have been described by reference to <FIG>. More generally, various combinations of baffle number, baffle length(s), baffle shape and connectivity between baffles and the protrusion <NUM> are envisaged.

Claim 1:
A consumable cartridge comprising:
a pot for centrifugal separation of a biological fluid into multiple components (<NUM>, <NUM>),
a cartridge body (<NUM>, <NUM>') adapted to receive the pot, and
a first holding means (<NUM>) for holding the pot at least partly within the cartridge body (<NUM>, <NUM>'),
wherein the first holding means is adapted to allow the pot to rotate,
the pot comprising a wall (<NUM>) around a central axis (<NUM>), a top end (<NUM>) and a bottom end (<NUM>), wherein the pot further comprises:
a plurality of baffles (<NUM>) protruding from the wall (<NUM>) into an inner volume of the pot; and/or
a protrusion (<NUM>) from the bottom end (<NUM>) into the inner volume and around the central axis,
the consumable cartridge further comprising a dispensing element (<NUM>) adapted to dispense a biological fluid (<NUM>, <NUM>) into the pot, and an aspirating element (<NUM>) adapted to extract a component (<NUM>) of the biological fluid from the pot.