Electroporation of single cells and tissues with an electrolyte-filled capillary

We show how an electrolyte-filled capillary (EFC) coupled to a high-voltage power supply can be used as a versatile electroporation tool for the deliv ery of dyes, drugs, and biomolecules to the cytoplasm of single cells and c ells in tissues. A large-voltage pulse applied across the EFC (fused silica , 30 cm long, 375-mum o.d., 30-mum i.d.) gives rise to a small electric fie ld outside the terminus of the EFC, which causes pore formation in cell mem branes and induces an electroosmotic flow of electrolyte. When the EFC cont ains cell-loading agents, then the electroosmotic flow delivers the agents at the site of pore formation. The combination of pore formation and delive ry enables loading of materials into the cytoplasm. By patch-clamp and fluo rescence microscopy, formation of pores was observed at estimated transmemb rane voltages of < 85 mV with half-maximum values around 206 mV. The electr oporation protocol was demonstrated by introduction of fluorogenic dyes int o single NG108-15 cells, cellular processes, and small populations of cells in organotypic hippocampal cultures. Preliminary results are shown in whic h this protocol was employed for in vivo electroporation of ventral mesence phalon in rat brains. The technique was also used to access organelle-based detection systems inside cells. As a demonstration, 1,4,5-inositoltriphosp hate was added to the electrolyte and detected by intracellular organelles in electroporated cells.