Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Reexamination Certificate
1997-07-23
2003-02-04
Soderquist, Arlen (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
C356S246000
Reexamination Certificate
active
06514464
ABSTRACT:
The invention relates to a microplate with transparent bottom as well as to a method for its manufacture.
Microplates are known which are used for fluorescence, luminescence or scintillation measurements, for example, in solving biochemical or molecular biological questions.
New luminescence and fluorescence techniques require the preparation of colored microplates with transparent bottoms. Microplates with 96 wells today represent a standardized platform for automatic or manual determinations, and for evaluation of patient specimens in widespread analysis equipment. A routine method for the preparation of colored microplates with transparent bottoms is ultrasound welding of a colored plate frame to a transparent bottom. It is preferable that both parts be made of polystyrene. Achieving an absolute seal between the 96 wells always turns out to be a problem. Therefore, double welding beads are frequently applied to achieve a greater level of safety.
EP-0,571,661 A1 discloses a microplate which is used in measurement techniques where the light emission or light permeability is measured. The disclosed microplate compresses a cuvette-forming upper light-impermeable frame part as well as a light-permeable bottom part, which is attached by means of ultrasound welding to the upper frame part. There are also known variants of these microplates in which, below the transparent bottom part, a protective grid is applied which is made of nontransparent material, and which leaves clear the optical window. Manufacture of such microplates may employ multicomponent injection molding processes, where, by means of two injection molds, the frame and bottom parts are manufactured and assembled.
The drawback of the known microplates is that the transparent bottom parts, because of their thickness of approximately 1 mm, present light conduction effects which are the result of the deflection and total reflection of light. Total reflection occurs whenever light moves through an interface between an optically denser medium and an optically less dense medium, and the limiting angle, which is specific for the material, is exceeded. This property is used to good effect today in light conduction technology. Light is fed into one end of a light conductor, then exits through the other end, practically unweakened because of the total reflection. To achieve this effect, the walls of the fibers must, however, be absolutely smooth at optical dimensions. If this is not the case, as in injection molded part, then the reflection of the light is not total, only partial, and therefore it can exit through adjacent walls, or cuvettes. The adverse light conduction effect also occurs, for example, during transmitted light measurements, and its characteristics include the fact that the transparent bottom acts as a light conductor and, for given cuvettes, deflects incident light partially into adjacent cuvettes. In this context, it has been observed that, as the thickness of the bottom increases, the light conduction effect also increases, that is, the measurement accuracy decreases. In addition, the known microplates are only suited under certain conditions for radioactivity measurements, for example, scintillation measurements, also because of the thickness of their transparent bottoms.
The technical problem which is the foundation of the present invention thus consists in preparing microplates which overcome the above-mentioned drawbacks, particularly which guarantee a higher accuracy during optical measurements and, moreover, are also suited for radioactive determinations.
The invention solves this problem by the preparation of a microplate with the characteristics of the main claim, particularly by the preparation of a microplate with at least one frame part and at least one bottom part associated with the frame part, where the frame part, of which there is at least one, comprises multiple cuvettes and the bottom part, of which there is at least one, forms the bottoms of the cuvettes, and where the bottom part, respectively the bottoms, of the cuvettes has/have a maximum thickness of 500 &mgr;m, preferably 20-500 &mgr;m, and optimally 40 to 100 &mgr;m.
In connection with the present invention, the term frame part of a microplate is understood to refer to that part of a microplate which forms the cuvettes or recesses, in particular their lateral walls, which are open towards both the top and bottom. The term bottom part of a microplate is understood to refer to that part of a microplate which closes off the cuvettes, and optionally the cuvette interstices, towards the bottom.
In connection with the present invention, the term cuvette is understood to refer to a container which can be made of any material, preferably plastic, and which is in the form of a cupule, well, bore, hollowed-out part or similar configuration, and which is used for receiving the samples the be examined. In a particularly preferred manner, the entire bottom part, or only those parts of the bottom part which form the bottoms of the cuvette, are made in the form of a membrane or, particularly, a transparent film.
The invention thus makes available, in an advantageous manner, a microplate which provides, because of the very small thickness of the bottom part, respectively the bottoms of the cuvettes, multiple advantages and applications. Because of the small thickness of the bottom part, respectively the bottoms of the individual cuvettes, it is, for example, possible and particularly advantageous for use in radioactivity determinations. To the extent that the bottom part is in the form of a transparent film, the resulting advantage is that the undesired light conduction effect is considerably reduced, so that measurements can be carried out with considerably increased accuracy, compared to the state of the art. To the extent that the bottom part is in the form of a membrane, it is possible to carry out any desired nutrient diffusion from the bottom through the membrane into the cells that grow on the membrane in the cuvette in a particularly efficient manner, and to a large extent unimpeded.
The microplates according to the invention are therefore suited for any kind of fluorescence, luminescence, colorimetric, chemilumescence or radioactivity measurement, for example, scintillation measurements. The microplates according to the invention can be used in ELISA tests, DNA and RNA hybridizations, antibody titer determinations, protein, peptide and immuno tests, PCR and recombinant DNA techniques, hormone and receptor binding tests and similar techniques. Since it is preferable to use, for the bottom part, respectively the bottoms of the individual cuvettes, transparent, that is light-permeable, materials, optical apparatuses can be placed both above and below the microplate. In addition it is possible to study the samples contained in the cuvettes using light microscopy.
The microplate according to the invention presents at least a frame part and at least one bottom part associated with the frame part. The frame part, of which there is at least one, is preferably essentially in the form of a rectangle and it comprises multiple cuvettes which are open towards the top and towards the bottom, in a support plate, where the lateral walls of the cuvettes are formed by the frame part which in this area is in the form of a support plate. The cuvettes that are formed in the frame part can have a circular, hexagonal, square or other geometric cross section. The cuvettes are arranged in the support plate of the frame part in the form of a matrix or in rows. The cuvettes in the support plate can be in the form of distinct individual cuvette, connected, for example, by connecting rods, in the form of bores in an otherwise solid support plate, or in the form of a combination of the two embodiments. Per frame part it is possible to have 6, 12, 24, 48, 96 or multiples thereof, for example, 384 or 1536, cuvettes. The frame part is applied in the injection molding process onto the bottom part which has a maximum thickness of 500 &mgr;m, which bottom part thus closes t
Fitch Even Tabin & Flannery
Greiner Bio-One GmbH
Soderquist Arlen
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