Abstract: This invention is an integrated instrument for the high-capacity electrophoretic analysis of biopolymer samples. It comprises a specialized high-voltage, electrophoretic module in which the migration lanes are formed between a bottom plate and a plurality of etched grooves in a top plate, the module permitting concurrent separation of 80 or more separate samples. In thermal contact with the bottom plate is a thermal control module incorporating a plurality of Peltier heat transfer devices for the control of temperature and gradients in the electrophoretic medium. Fragments are detected by a transmission imaging spectrograph which simultaneously spatially focuses and spectrally resolves the detection region of all the migration lanes. The spectrograph comprises a transmission dispersion element and a CCD array to detect signals. Signal analysis comprises the steps of noise filtering, comparison in a configuration space with signal prototypes, and selection of the best prototype.

Abstract: A high dynamic range apparatus for separation and detection of polynucleotide fragments has a housing adapted to receive an electrophoresis gel holder containing an electrophoresis gel loaded with fluorophore-labeled samples; one or more laser diodes for providing radiation of a frequency suitable for excitation of the fluorophore which irradiates a an array of excitation/detection sites on the electrophoresis gel; an array of detectors aligned with the excitation/detection sites for collecting fluorescent emissions; and one or more components for increasing the dynamic range of the instrument by at least an order of magnitude.

Abstract: Improved detection methods and apparatus which may be used individually or in combinations enhance the ability of the electrophoresis apparatus to detect fluorophore-labeled materials in short periods of time.

Abstract: The present invention relates to the electrophoretic separation of bio-organic molecules using a slab gel electrophoresis apparatus having a pair of spaced, confronting plates defining a multi-lane separation zone adapted to hold a separation medium and an upper loading zone. In one aspect of the invention, at least one of the plates is shaped to provide an expanded loading zone. The plate-to-plate distance within the expanded loading zone is greater than the plate-to-plate width within the separation zone. In another aspect of the invention, a comb is provided with each tooth having a gradual taper beginning at a support member and extending along most of the tooth's longitudinal axis, and a sharp taper beginning immediately beyond the gradual taper and extending to the end of the tooth.

Abstract: The present invention provides an integrated, fully automated, high-throughput system for two-dimensional electrophoresis comprised of gel-making machines, gel processing machines, gel compositions and geometries, gel handling systems, sample preparation systems, software and methods. The system is capable of continuous operation at high-throughput to allow construction of large quantitative data sets.

Abstract: The present invention involves a power application device including a flat power pad having an electrically insulating support that supports first and second conductive regions. The first conductive region is connected to a positive output terminal of a power supply, and the second conductive region is connected to a negative terminal of the same power supply. The power application device may be used with electrophoresis gel carrier modules of various dimensions having first and second conductive paths leading from the vicinity of each end of the gel to separate external electrical contacts points. The external electrical contact points can each make contact with the conductive regions upon which the electrophoresis gel module sits. When properly positioned on the power pad, the electrophoresis gel module spans the distance between two conductive regions of opposite charge and the external contact points of the electrophoresis module make electrical contact with the conductive regions.

Abstract: A micro injector sample delivery system for charged molecules. The injector is used for collecting and delivering controlled amounts of charged molecule samples for subsequent analysis. The injector delivery system can be scaled to large numbers (>96) for sample delivery to massively parallel high throughput analysis systems. The essence of the injector system is an electric field controllable loading tip including a section of porous material. By applying the appropriate polarity bias potential to the injector tip, charged molecules will migrate into porous material, and by reversing the polarity bias potential the molecules are ejected or forced away from the tip. The invention has application for uptake of charged biological molecules (e.g. proteins, nucleic acids, polymers, etc.) for delivery to analytical systems, and can be used in automated sample delivery systems.

Abstract: An apparatus and method for loading samples into a gel of an electrophoretic gel system (EGS). The preferred sample loader includes a membrane having a net negative charge, net neutral charge or no charge (preferably nitrocellulose or nylon) which releasably retains the samples such that the samples are actively released when the membrane is inserted into the gel of an EGS. In one preferred embodiment, the sample loader includes a substrate having a plurality of sample loading areas extending therefrom. In an alternative embodiment, the membrane is substantially thick and serves as its own substrate. In another embodiment, sample inhibiting agents such as hydrophobic ink are formed through the membrane to inhibit the diffusion of samples between sample loading areas. Each sample loading area includes an affixed membrane. In use, one or more samples to be subjected to electrophoretic action are applied to the membrane before the membrane is inserted into a previously polymerized gel.

Abstract: A sample holding device for electrophoresis apparatus according to the present invention wherein a plurality of sample holding capillaries are laid out in an array and are immobilized to the supporting jig. This sample holding device is configured to ensure the lower ends of the capillaries can contact the sample injection portion of the electrophoresis separation part of the electrophoresis apparatus, and provides easy sample injection and prevents the gel capillaries of the electrophoresis separation part from being damaged when sample holding capillaries are filled with gels, thereby allowing repeated use of the gel capillaries of the electrophoresis separation part.

Abstract: A method and apparatus for achieving uniform illumination in an electrophoresis apparatus is provided. Uniform illumination allows quantitative measurements of an electrophoresis gel to be made, thus increasing the information which can be obtained from an electrophoretic analysis. Uniform illumination is achieved by scanning the light source, preferably in a trans-illumination mode, across the sample gel in a direction perpendicular to the axis of the source. The light source is comprised of one or more light bulbs placed in a light tray. Variations in light intensity near the source end portions may be minimized using a variety of techniques including extended light bulbs, filters, reflectors, diffusers, or supplemental sources.

Abstract: A microminiature sequencing apparatus and method provide means for simultaneously obtaining sequences of plural polynucleotide strands. The apparatus comprises a microchip into which plural channels have been etched using standard lithographic procedures and chemical wet etching. The channels include a reaction well and a separating section. Enclosing the channels is accomplished by bonding a transparent cover plate over the apparatus. A first oligonucleotide strand is chemically affixed to the apparatus through an alkyl chain. Subsequent nucleotides are selected by complementary base pair bonding. A target nucleotide strand is used to produce a family of labelled sequencing strands in each channel which are separated in the separating section. During or following separation the sequences are determined using appropriate detection means.

Abstract: This invention provides a gel electrophoresis casting cassette for horizontal gel electrophoresis. The tray and lid of the cassette have locking means for securing the two parts to prevent damage to the slab gel and to create slab gels of uniform quality.

Abstract: The invention relates to a separation procedure for Lp(a) and the various lipoproteins contained in a biological sample by electrophoresis. The present invention is characterized in that the electrophoretic migration of the lipoproteins is carried out under conditions such that the electrophoresis gel and/or the above-mentioned biological sample contains compounds capable of modifying the electrophoretic mobility of Lp(a) differentially with respect to that of the other lipoproteins.

Abstract: A gel and buffer system for gel electrophoresis wherein separation occurs at neutral pH.

Abstract: Changes in polarized light incident on a detection zone within a separation matrix are used to detect optically active molecules within the separation matrix. The separation and detection of optically active molecules within the detection zone is done by loading a sample containing optically active molecules onto a separation matrix; applying a motive force to cause the sample to migrate though the separation matrix and to separate into a plurality of subgroups of optically active molecules; directing an incident beam of polarized radiation to the detection zone; processing the collected exiting beam with an optical component which discriminates between radiation having the same polarization as the incident beam and radiation having a different polarization from the incident beam; and measuring the intensity of the processed exiting beam.

Abstract: An apparatus of conducting electrophoresis experiments including a container for receiving an electrophoresis buffer and a buffer core assembly for holding gel-containing cassettes that are immersed in the buffer for molecular separation of an electrophoresis sample. The buffer core assembly defines a flow path for the electrophoresis buffer which can be circulated by means of a heat exchanger and a pump to effect controlled heat exchange between the buffer and the cassette surfaces thereby maintaining the gel and the electrophoresis process at a desirable temperature uniformly over the surfaces of the gel cassette. The buffer core assembly also has upper well for receiving a second electrically chargeable buffer in contact with the gel so as to impose an electric field on the gel for the electrophoresis in conjunction with the first buffer. The well is isolated from the first buffer to prevent mixing of the buffers and to reduce the risk of an electrical short.

Abstract: A gel electrophoresis apparatus and a cooling system therefor. The apparatus includes a front panel and a back panel. A gel slab is contained in a gel slab platform between the front and back panels. The gel slab platform extends upwardly to the front edge of an upper buffer reservoir and downwardly to a lower buffer reservoir. A conventional gel mold assembly is inserted into the apparatus and supported by the gel slab platform. A cooling unit is disposed below the lower buffer reservoir of the apparatus. A baffle plate is inserted between the front panel and a back panel of the apparatus. When the cooling unit is actuated, the baffle plate directs a cooling medium through the apparatus and between the front panel and the back panel to cool the gel slab. The apparatus also includes dampers which are pivotally mounted on the apparatus at the top of the baffle plate. The dampers are used to control the flow of the cooling medium through each baffle individually.

Abstract: An electrophoresis microgel is formed in a gel holder. The gel holder comprises a top substrate, a bottom substrate and a spacer disposed between the top substrate and the bottom substrate. The spacer establishes a separation of from 25 to 250 microns between the top substrate and the bottom substrate. A gel compartment is formed by partially sealing the top substrate to the bottom substrate, while leaving an opening for the introduction of unpolymerized gel. The gel compartment is then filled with an unpolymerized gel, which is polymerized in the gel compartment. Electrodes may be printed on the substrates, may be contacts to an exposed edge of gel, or may be applied through windows cut into one of the substrates. One type of gel holder makes use of graded beads having a diameter of 25 to 250 microns slurried in an adhesive such as an acrylate adhesive as the spacer. The slurry is printed onto the surface of one or both substrates to form a spacer of the desired shape, and then hardened using heat or light.

Abstract: A fully automated protein and/or DNA gene fragment analyzing machine and method are disclosed in which, in a simple machine structure, a plurality of electrophoresis cells each containing such fragments, are robotically, under computer programming, inserted into an electrophoresis housing and subjected to voltage for producing electrophoretic migration in one dimension (horizontally), and then preferably after robotic 90.degree. rotating of the cells, are voltage migrated in an orthogonal direction to separate the fragments vertically, and then robotically presented to an optical image scanner for identifying the brightest fragments and classifying the same, with comparison with reference image fragment locations of normal or variant fragments, and for computer storing all relevant data.

Abstract: A sample holder for receiving, containing and storing multiple samples for delivery to an electrophoretic gel; and a method of preparing a gel for electrophoresis such that samples are first loaded onto a separate holder which can then be positioned at an edge of a gel bed surface while the electrophoretic gel is poured, whereby after solidifcation thereof the sample holder is removed leaving the samples adhered in a position for delivery to the electrophoretic gel after current is applied to the system.

Abstract: An electrophoresis apparatus for automatically performing medical assays includes an electrophoresis platform which cooperates with a gantry assembly. The electrophoresis platform and the gantry assembly are movable along paths that are perpendicular to each other. An applicator assembly includes pipettes which transfer fluid samples from a specimen tray to an electrophoresis plate mounted on the electrophoresis platform. The electrophoresis platform then moves to a position into the gantry assembly, where electrophoresis is conducted to separate the samples into different fractions. The electrophoresis platform then moves beneath a reagent pouring station where a reagent is applied to make the separated fractions fluoresce under ultraviolet light. The electrophoresis platform is then moved beneath the gantry assembly again, and an air knife in the gantry assembly spreads the reagent.

Abstract: An electrophoresis gel cassette that includes a bottom plate with an attached base portion, a cover plate, and a gel chamber formed between the two plates. There is at least one opening, which is in communication with the gel chamber, encompassed in the base portion, thereby making the opening seamless or free of parting lines. Upon assembling the cassette, a contact face of the base portion of the bottom plate and a contact face of the cover plate can be sealed by sonic welding or adhesives to produce a water-tight seal and to facilitate casting.

Abstract: A gel for electrophoresis in a horizontal mode which contains at least one sample well with an enlarged loading area that is formed in an elevated gel segment. At least a front wall of the sample well consists of a substantially vertical part and a non-vertical part, where the non-vertical part is declined at an angle sufficiently steep that the sample loaded on the non-vertical part slides down into the sample well. Any sample molecules that during electrophoresis enter the gel through the non-vertical part of the front wall migrate only through the elevated gel segment. They also exit this segment, so that substantially no double bands, which could complicate the interpretation of experimental results, are detected.

Abstract: The time, difficulty, and expense of running DNA sequencing gels is substantially reduced by running the DNA sequence in a minigel of approximately 8.times.11 cm at a reduced electrophoretic voltage and without preheating the buffer solution in contact with the gel. The image produced from the sequence gel or autoradiograph is then scanned with a CCD line camera. The pixel map of the autoradiograph image is then magnified using software techniques within the computer so that it is displayed on the CRT screen at an increased scale permitting easy visual separation between the DNA bands.

Abstract: A method for determining the nucleotide size of DNA fragments separated by gel electrophoresis, comprising the steps of (i) measuring the migration time of each detected DNA fragment, and (ii) correlating the size of each detected DNA fragment with its migration time.

Abstract: The present invention is directed to methods and apparatus for simultaneous gel electrophoresis analysis of multiple nucleic acid samples. The invention provides an electrophoresis gel-matrix layer having two mutually opposite ends for application of an electrophoresis voltage thereto, an exposed major surface extending between the two ends, and a plurality of wells in the thickness of the layer and open at said exposed surface, wherein the wells are arranged in a plurality of rows each extending transversely of the end-to-end direction of the layer and wherein the wells in successive rows are aligned with each other so as to form columns which are aligned in the end-to-end direction said gel-matrix layer further comprising two slots positioned at opposing ends of the plurality of open sample wells for insertion of electrophoresis electrodes.

Abstract: A strip gel that may be water-swellable and a slab gel are combined on a common support for two-dimensional electrophoresis, with the strip gel isolated from the slab gel by a fluid-impermeable and electrically insulting barrier, which is preferably one wall of an enclosure that forms a reservoir for containing the strip gel. The first dimension separation is performed by placing the liquid sample and buffer in the reservoir to cause the gel to swell and to load it with sample, then passing an electric current through the reservoir. The barrier, which is joined to the support in an easily breakable manner, is then removed, and the strip gel is placed in contact with the slab gel for the second dimension separation.

Abstract: A method of gel electrophoresis carried out in a submerged gel mode in which the gel is a bed of water insoluble, transparent, cross linked gel, which has been formed by: dissolving a polysaccharide, including at least one linear polysaccharide such as agarose or hydroxyethyl cellulose, in a suitable solvent, such as water; adding a cross linking agent, which is not charged nor becomes charged upon contact with water in a pH in the range of about 2 to 11, to the solution; and incubating this mixture in a quiescent state to substantially simultaneously react the polysaccharide and the cross linking agent and to gel the reaction product into a bed. The polysaccharide is at least one linear polysaccharides, but that linear polysaccharide may also be admixed with other linear polysaccharides and/or at least one non-linear polysaccharide. Synthetic organic polymers may also be admixed in the cross linking reaction mixture.

Abstract: A method of electrophoresis and providing electrophoresis support medium in lane-by-lane formation, each lane having a sample loading well and for electrophoresis gel lanes are transferred to electrophoresis tank lane by lane and used for electrophoresis.

Abstract: In accordance with the teachings of the present invention, there are provided methods, gels, and transferring devices for loading gels. The methods and devices of the present invention involve the use of ultra-thin, miniature, disposable, slab gels for the quick, inexpensive and high resolution analysis of polynucleotide samples.

Abstract: A hybrid slab-microchannel gel electrophoresis system. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate.

Abstract: A spacer in the form of an elongated, rectangular parallelepiped for use between the two glass plates of a gel cassette to delimit a space for receiving an electrophoresis gel between the glass plates where the spacer is made of glass.

Abstract: Improved detection methods and apparatus which may be used individually or in various combinations enhance the ability of the electrophoresis apparatus to detect fluorophore-labeled materials in short periods of time.

Abstract: A device and method for vertical slab gel casting and electrophoresis in a single enclosure is provided. Air is utilized as a sealing medium to seal the bottom of a gel space for gel casting by constructing an air-tight connection between a sealable lower buffer chamber and a gel space via a junction. The air is automatically released when a buffer is introduce into the lower buffer chamber so that the bottom of the gel is in direct contact with the buffer without manually removing a solid sealing device from the bottom of the gel, which enables the gel to be directly used for electrophoresis without any movement of the gel space.

Abstract: This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

Abstract: The present invention is a sample deposition device for depositing a plurality of samples onto a test media substrate, and a method of depositing a plurality of samples onto a planar test media substrate, such as a stationary phase chromatographic medium, agar or tissue. In broadest terms, the device of the present invention comprises (a) a substantially planar support portion defining a plane; and (b) an array of substantially planar absorbent portions permanently connected to the support portion, the absorbent portions aligned substantially parallel to said plane. The absorbent portions may be impregnated with a test sample before use. The present invention also includes a method of depositing one or more samples onto a test media substrate.

Abstract: The present invention relates to an electrophoresis media comprising a gel and a compound capable of restricting the diffusion of water within the gel. Diffusion restricting compounds useful in the present invention include but are not limited to polyols, polymeric alcohols, polysaccharides, polyoxyethylene ethers, polyamines, polypeptides, gums, zwiterionic detergents and mixtures thereof. The present method relates to any electrophoresis media and includes but is not limited to polyacrylamide, agarose, starch, cellulose acetate and sepharose. A further embodiment of the present invention relates to a stacking gel wherein a diffusion restricting compound is used to prevent diffusion of water between the stack gel and resolving gel. The addition of a diffusion restricting compound to the stacking gel has the particular advantage of causing the stacking gel to become opaque, thereby facilitating the addition of samples to the gel.

Abstract: The loading of samples into wells that are formed in a vertical slab gel is facilitated by a needle guide that provides expanded openings that taper toward the wells, the openings being separated by partitions that help the user distinguish between the wells and the barriers of transparent gel material between the wells.

Abstract: An apparatus for electroelution isolation of biomolecules and recovering biomolecules after elution including a tubular enclosure for engaging a piece of separating gel having a band of biomolecules. The enclosure is capped by a closure means having a passage means, and then placed in an electrophoresis tank with the closure means facing the positive terminal. Applying an electric current forces the biomolecules to accumulate at the closure means. The biomolecules may be recovered by inserting a capillary tip through the passage means and drawing the biomolecules through the capillary.

Abstract: An electrophoresis gel carrier includes end mounts, each having a buffer well and retainer elements constructed to support an electrophoresis medium gel so that the gel is in communication with the buffer well. Each end mount includes a base plate which defines the buffer well as well as a lower retainer element. Each end mount also includes an upper retainer element which when aligned with the lower retainer defines an opening in fluid communication with the buffer well. The openings in each of the end mounts receive opposite ends of the electrophoresis medium gel so that the gel is in communication with the buffer well. An apparatus is provided which allows a number of electrophoresis gels, mounted in gel carriers, to be analyzed using a single detector.

Abstract: To sequence DNA automatically, DNA marked with far infrared, near infrared, or infrared fluorescent dyes are electrophoresed in a plurality of channels through a gel electrophoresis slab or capillary tubes wherein the DNA samples are resolved in accordance with the size of DNA fragments in the gel electrophoresis slab or capillary tubes into fluorescently marked DNA bands. The separated samples are scanned photoelectrically with a laser diode and a sensor, wherein the laser scans with scanning light at a wavelength within the absorbance spectrum of said fluorescently marked DNA samples and light is sensed at the emission wavelength of the marked DNA.

Abstract: Separation media for electrophoresis, and methods of filling and flushing of electrophoretic devices such as capillaries are described. By preparing submicron to above-micron sized cross-linked gel particles and using gel swelling equilibrium concepts, such devices can be easily filled and flushed. Gel particles can be prepared by inverse suspension, precipitation and suspension polymerization. These particles can be swollen and collapsed by small changes in temperature, pH, and ionic strength of solvent. Other approaches involve the formation of reversible cross-links by use of polyelectrolyte complexes, chelating agents or copolymers of hydrophobic and hydrophilic repeat units. Finally, reversibly solubilized systems may be used to change the viscosity of the media.

Abstract: The invention relates to an apparatus for two-dimensional electrophoresis of at least one electrophoresis unit comprising an electrophoresis medium enclosed between two plates, which apparatus comprises a first pair and a second pair of compartments for electrophoresis liquid which are provided with electrodes and which make electrophoretic contact on either side and mutually transversely of each other with the electrophoresis medium of the electrophoresis unit, wherein the compartments are disposed and adapted such that the electrophoresis unit assumes a standing position in the apparatus, and to an electrophoresis unit intended for such an apparatus.

Abstract: The improved DNA base sequencer has a flat plate type gel electrophoretic unit that has multiple tracks for electrophoresing DNA fragments and which is held in a vertical position, a light exciting laser light applying unit that applies laser light to the respective tracks in the electrophoretic unit from one lateral side thereof in such a way that it crosses the tracks at right angles, and a fluorescence detecting unit that detects the fluorescence as generated from the DNA fragments illuminated with the laser light and which converts the detected fluorescence to an electric signal. The sequencer is characterized in that the fluorescence detecting unit comprises a fluorescence condensing lens, a fluorescence filtering unit and a solid-state imaging device, (e.g., a CCD line sensor), the fluorescence filtering unit being composed of at least two filters that selectively transmit fluorescences having different wavelengths and that are staggered with each other along a common longitudinal axis.

Abstract: A gel electrophoresis method and apparatus is described in which the shape and orientation of the electric field is controlled by contour clamping. Electrodes are arranged around a closed contour. Two or more electrodes, the driving electrodes, are clamped at a potential difference .phi..sub.0 to establish the general orientation and strength of the electric field. The remaining electrodes are clamped to intermediate potentials to control the shape of the field established by the driving electrodes. The field is varied in accordance with the purpose of the electrophoresis, depending upon the size of the particles and the information to be determined concerning the particles.

Abstract: A device and method of direct water cooling for horizontal submarine gel electrophoresis is provided. A cooling water is utilized to replace a buffer for immersing a gel matrix during electrophoresis. The replacement offers an excellent heat absorption and a substantial reduction of electric current simultaneously, which enables the horizontal submarine gel electrophoresis to be performed at elevated voltages.

Abstract: The present invention pertains to a process which can be fully automated for accurately determining the alleles of STR genetic markers. More specifically, the present invention is related to performing PCR amplification on locations of DNA, labelling the PCR products, converting the labels into a signal, removing a reproducible PCR stutter pattern from the signal by means of a computational device, and then determining the genotype of the location of the DNA. An amplification can include multiple locations from the DNA of one or more individuals. The invention also pertains to genetics applications and systems which can effectively use this genotyping information.

Abstract: A flow-through receptacle is disclosed, one end of which is designed to hold multiple plugs of gel material, containing solutes such as macromolecules, excised from electrophoretic separations, and the other end of which is capable of insertion into a recipient matrix that lies between the plates of a slab gel enclosure in an electrophoresis apparatus. The receptacle is used to place the gel plugs, containing the macromolecules or solutes, into electrophoretic contact with a recipient matrix and allows for electrophoretic transfer of the solutes from the plugs into a single concentrated zone in the recipient matrix. The concentrated macromolecules or solutes can then be further processed in the recipient gel or excised and used for procedures requiring greater amounts and concentrations of the solute than are available in the original plugs.

Abstract: Electrophoresis apparatus with a gel support configured and arranged to hold a gel, a buffer chamber configured and arranged to hold a buffer, with the buffer contacting each end of the gel, and a buffer shaper configured to be positioned near the gel support and in contact with the buffer. The buffer shaper is positioned nearer to one portion of the gel support than to another portion of the gel support to cause the depth of buffer between the gel support and the buffer shaper to vary along the length or width of the gel support and buffer shaper.

Abstract: Multiple, typically 5+, trays of an identical special configuration are vertically stacked one atop the next, end-to-end reversed. Each tray has an overflow feature, normally in the form of either (i) a portion of a side that is reduced in height so as to form a lip, (ii) a corner hole protected by a removable baffle of selectable height, or (iii) a threaded standpipe that may be screwed to variable height. The overflow feature permits that liquid will overflow each tray only upon reaching a predetermined height in a reservoir of the tray. A liquid poured in the top tray cascades downwards from tray to tray, filling each tray to a uniform even level and ultimately reaching the bottom tray of the stack. The liquid that is within each tray is permitted to gel, forming thereby a gel state material that is suitable to receive samples upon which electrophoresis may be conducted. Combination spacer and toothed comb elements are optionally inserted between the stacked trays.