Abstract:
An apparatus for removing solid bodies from an array of reaction vessels includes a frame and a plurality of lifters, each lifter for holding a solid body disposed within a reaction vessel for removal therefrom. The lifters are mounted on the frame in an array corresponding to the array of reaction vessels such that the array of lifters is positionable within the array of vessels in a manner which permits placement of a solid body in each vessel on each lifter while the lifters are positioned in the vessels.

Description:
This application is a continuation of application Ser. No. 08/074,323, filed Jun. 9, 1993 now abandoned. 
    
    
     FIELD OF INVENTION 
     The invention relates to an auxiliary device to be used in a laboratory, by means of which device a solid body in a reaction vessel can be removed. 
     PRIOR ART 
     In several countries, analyses are made as a routine measure from a blood sample taken from all newborn babies, so that certain illnesses (e.g. insufficiency of thyroid gland) could be followed and treated as early as possible. The amounts of samples are naturally very large and it is most advantageous to analyze them in large series, whereby it is possible to reach as high a level of automation as possible. 
     A blood sample for the above-mentioned analyses is usually taken by absorption onto a filter paper, whereby its storage and dispatch to a laboratory performing the analyses is easy. In the laboratory, a small disk (diameter ca. 3-5 mm) is punched off the filter paper, from which disk the sample is eluted into a solution in a reaction vessel. As a reaction vessel e.g. wells of an 8×12 microtitration plate are used, whereby it is possible to simultaneously perform up to 96 analyses. After the eluation, the disk of paper is removed from the solution or the solution is transferred to other wells for further treatment. 
     In methods used currently, the disk of paper is usually removed from the reactor vessel by means of a pair of tweezers or a needle. This is already cumbersome as such, and it has to be performed separately for each well. It is also very difficult to press the disk always in exactly the same way, because of which the amount of the fluid leaving the well varies. The use of a needle is on its part still more cumbersome than that of a pair of tweezers. 
     A suction device has also been used for removing the disks, by means of which device the sheets are removed with suction pipes to be placed in the wells. These methods cannot be used, if the eluation fluid has to remain in the well. 
     GENERAL DESCRIPTION OF INVENTION 
     The invented device is meant to be used in sets of cuvettes comprised of several vessels. The device has a framework and therein, at a point corresponding to each vessel, a solid-body lifter positioning in the vessel. All bodies may thus be simultaneously lifted off the vessels in a single step. 
     DETAILED DESCRIPTION OF INVENTION 
     The invented device has a framework to be placed in a set of cuvettes, and fixed lifters thereunder. At the lower end of the lifters there is a retainer. The retainer can be especially formed by transverse bars. The device is dimensioned and constructed such that when it is placed on top of a set of cuvettes, e.g. a microtitration plate, intended to be used together therewith, the retainers position in the vessels of the set of cuvettes. The framework contains openings such that the openings provide access to each vessel. In this way, the desired solid body may be taken on the retainer into the vessel for a reaction. 
     The device is especially applicable to be used in the elution of samples, e.g. blood, urine or excrement samples, absorbed onto a filter paper. 
    
    
     Some preferable applications of the invention are described in the following in more detail. In the drawings of the description: 
     FIG. 1 shows an invented device seen from the front; 
     FIG. 2 shows the same device seen from above; 
     FIG. 3 shows an alternative part of the device from behind as enlarged and cut; 
     FIG. 4 shows another invented device seen from above; 
     FIG. 5 shows a third invented device shown from the front; 
     FIG. 6 shows the device of FIG. 5 from above; and 
     FIG. 7 shows a detail of FIG. 5 as enlarged and cut. 
    
    
     The lifting device of FIGS. 1 and 2 is meant to be used together with 8×12 microtitration plates. The device has a rectangular frame 1. Its long sides are connected with twelve transverse bars 2 corresponding to the spacing of the vertical rows of the plate. 
     Eight lifters 3 are fixed to each bar 2 corresponding to the spacing of the horizontal rows of the plate. The width of the lifters is smaller than the diameter of the wells of the plate. 
     The device can be placed on the plate such that the lifters 3 position in the wells of the plate. 
     The lifter 3 has an arm 4 extending directly downwards from the bar 2 and at its lower end there is located a tongue 5. The tongue is so wide that a filter paper piece of a width of 3-5 mm cannot drop from it to the bottom of the well. The bars 2 and the arms 4 are dimensioned and positioned on the edge of the row of wells such that the paper pieces may be freely placed in the wells. 
     The tongue 5 has a round ring and in the middle of it a transverse framework. The fluid in the well can thus easily come into contact with the whole piece. 
     The tongue 5 of FIG. 3 has six radial supports, one of which is fixed to the arm 4. At the end of the other supports there is provided a vertically extending stop, whose upper end is chamfered to slant to the center side of the tongue 5. The stops keep the paper disk well in position. In addition, the fluid comes very well into contact with the paper. 
     The device is placed on an empty microtitration plate and the paper pieces containing the samples are placed in the wells on the tongues 5, after which an elution solution is dispensed into the wells. After the elution has occurred, the device and all paper pieces together with it are lifted off the wells. The elution solution thus remains in the wells. 
     Depending on the method, the inner surfaces of the wells may have been coated e.g. with an antibody required in the assay method. 
     The usage of the device both facilitates and speeds up the performance of the assays. It also increases the repeatability of the assays. 
     FIG. 4 shows a smaller device, which is intended to be used, when assays are performed only in some of the wells of microtitration plate (e.g. MICROSTRIP® plates). 
     The device of FIG. 4 has three transverse bars 2 parallel with the vertical rows of the plate, which bars 2 are connected at their ends by supports 1&#39;. The bars 2 have lifters 3. Here, the tongue 5&#39; of the lifters 3 has a mere ring. 
     In the embodiment of FIGS. 5-7 there is a rectangular frame plate 1.1 with holes corresponding the places of 8×4 wells in a microtitration plate. On the under side of the frame plate 1.1, at the edge of each hole there are four downwards projecting lifting arms 4.1 to form a lifter 3.1. The under ends of the arms 4.1 are connected transversely by horizontal bars to form a retainer 5.1. The lifting arms 4.1 and the retainer 5.1 term a basket for the solid body. Near the retainer 5.1, the lifting arms 4.1 are further connected with a circular ring 6. This structure is rigid and easy to manufacture. The ring 6 further prevents the solid body such a paper disk from dropping to the well. 
     The device is most preferably manufactured from a plastic suitable for the application, e.g. polystyrene by injection moulding. A transparent plastic is the most preferable, since e.g. the changing of the color of the fluid in the wells may then be followed as freely as possible. 
     The device can be used in a similar manner also for removing other solid bodies. Such a body may be e.g. a plastic body used in immunomethods, to the surface of which body has been fixed an antibody or an antigen. The retainer tongue can be formed specially in accordance with the body to be used. 
     According to one embodiment, the inner surfaces of the wells have been coated with a first reagent, such as antibody, and the retainers with a second reagent. After the elution, a first assay is performed in the wells, and the retainers are transferred into another plate for performing a second assay.