The Hoefer SE 250 Mini-Vertical Gel Electrophoresis Unit is a small format vertical slab gel unit for rapid electrophoresis. It is very compact, measuring 16.5 x 16 x 16 cm. It can accommodate one or two 10 x 8 cm gel sandwiches, made using the Hoefer SE 245 Dual Gel Caster. The SE 250 unit is only compatible with GE Healthcare's Electrophoresis Power Supply EPS 301. The EPS 301 has a maximum wattage of 12 W, maximum voltage of 500V, and maximum amperage of 500 mA.
The upper chamber of the Hoefer SE 250 Mini-Vertical Gel Electrophoresis Unit is formed by the notched side of a gel sandwich against a silicone rubber casket. The spring clamps on each side of the chamber hold the gel sandwich plates tightly against the upper chamber core. The upper chamber core is positioned relative to the lower buffer chamber by positioning tabs which snap into place. Running buffer is poured inside the upper buffer chamber, which only requires about 120 ml for one gel and about 150 ml when running two gels. The safety lid is placed on top of the unit and the leads are plugged into the EPS 301 power supply.
Connecting the electrophoresis unit to the power supply is easy, as is setting the parameters for running. The front panel consists of a numerical display showing volts, milliamps, and time (hour:minute); a keyboard with six membrane keys; a light emitting diode that lights when voltage is applied; and output sockets for two electrophoresis units. The four-digit numerical display guides you through the programming and also shows the actual parameter values during the run and the final parameter values after the run. The voltage range is 5-300 V, current range is 10-400 mA, and the timer range is 0.01-23.59 hr; the system can also be run with the timer off. The keyboard is set up very conveniently. By just pressing ‘set’, one can enter values for voltage, current, and time, and then just press ‘run’. Pressing the ‘up/down’ key continuously changes the values quickly instead of in small increments. Also, during the run, one can change any one of the three parameters at any time. There is also a ‘view’ key which shows the actual values for each parameter. There is an alarm when the run comes to an end; it would be nice if the alarm were louder. You can store programs in this unit, but it is very limited in its function. After the parameter values are set and the run finished, pressing the ‘stop’ key saves the displayed values. When the power supply is switched on again later, the programmed values from the last run are saved and can be used directly by simply pressing ‘run’ again.
Hee Chul Lee
Research Fellow
University of Michigan
Internal Medicine