Abstract: Gradient gels for electrophoresis are produced by an apparatus in which a pair of syringes are mounted on a support rack together with cams arranged for synchronous rotation. Cam followers engaged by the cams are linked to the syringe barrels, with each cam defining a distinct spiral path translated by one of the cam followers into a preselected rate or rate profile of volumetric discharge from one of the syringes as the cam rotates. With the rate or rate profile established by one cam being distinct from the rate or rate profile established by the other, a gradient or other variation in composition is obtained when the syringe discharges are combined into a common stream and directed to the gel enclosure for solidification into a gel. The gradient or variation in composition is determined by the cam profiles alone, and is independent of the rate at which the cams are rotated, and of whether or not the rotation is performed in a steady manner.

Abstract: A comb to be used for holding samples and defining sample lanes in an ultra-thin slab gel in vertical slab gel electrophoresis is constructed with to form tapered or wedged-shaped sample wells, with the narrowest edge of the wedge opening into the upper edge of the gel. In one embodiment, the comb has a wedge-shaped profile along the contact edge to provide an expanded well at each sample location. Notches alternating with grooves are cut into the wedge shape to form teeth which taper along orthogonal axes, the wells being defined by the space between each adjacent pair of teeth. The gel enclosure which holds the slab gel is formed by plates which are shaped along one edge to provide a complementary wedge-shaped opening leading into the gel space. The comb fits snugly into the opening with the teeth of the comb touching or extending a short distance into the upper exposed surface of the gel. In another embodiment, the comb has a rectangular profile, with grooves cut to a varying depth to form the wedge shape.

Abstract: A gel enclosure and buffer tank for vertical slab gel electrophoresis are disclosed. The gel enclosure is formed from two flat plates, one of which contains angled troughs extending off to one side to serve as extensions of the sample wells, thereby increasing the volumetric capacity of each sample well, and improving the ease of loading it with sample. The buffer tank is constructed in such a manner as to hold one flat plate of the gel enclosure in contact with a flat heat transfer wall of the buffer tank, with cooling applied to the outside of the wall by thermoelectric means. Buffer solution below the gel enclosure is also cooled by the cooling wall, and bubbles generated at an electrode, also positioned below the gel enclosure, agitate the cooled buffer solution, extending the cooling effect over the entire surface of the other flat plate of the gel enclosure.

Abstract: Electrophoretic extraction of molecular species from a separation medium such as a gel segment is achieved by placing the separation medium in a tube closed at one end by a retaining material such as glass frit, and sealing the closed end of the tube against the mouth of a receiving cup which has a semi-permeable membrane (such as a dialysis membrane) for its bottom. The tube with receiving cup attached is inserted in a tube electrophoresis cell such as those commonly used in analytical laboratories. As current passes through the tube, the molecular species migrates from the separation medium to pass through the retaining frit and collect on the membrane for subsequent recovery.