Micro-technique for Cell Electrophoresis

Abstract

SEVERAL apparatuses have been described for measuring the electrical charge of small particles, such as cells^1–9. Due to the relatively large volume of the chambers used, and the minimum cell concentration necessary for adequate measurements, the total number of cells required for each measurement is rather large. When working with small samples, one sometimes finds it impossible to meet these requirements, and micromethods have therefore been developed. Theoretically, three different approaches are possible: to decrease the total volume of the chamber, to build the apparatus from several parts and fill only one of them with the cell suspension, or to introduce the sample to the measuring-place of a previously-filled chamber. The first of these possibilities is made complicated because of contamination by the electrodes. The second has been used by Seaman and Heard¹⁰, who built their apparatus from three parts. In their device only the microelectrophoresis tube is filled with the sample, while the electrode compartments remain ‘cell-free’. This system handles samples of the order of 1 ml. or even less. The third possibility has recently been explored by Forrester et al.¹¹, who have been able to reduce the minimum suspension volume to 0.1–0.2 ml. (ref. 12). The small size and low cell numbers of the organ rudiments we have been investigating have forced us to use even smaller volumes. This led us to modify the apparatus described by Bangham et al.⁹.