A piezoelectric device to aid penetration of small nerve fibers with microelectrodes.

A small piezoelectric device for cell penetration is described. It retracts the micropipette slowly by electrostriction, and pushes it very fast (less than 5 microsecond) forward by short-circuiting the transducer. The design, operation circuit, and performance under test conditions are described. Penetration examples from small nerve fibers (less than 5 micrometer) show that membrane puncture occurs only with the fast forward push. Cells are not noticeably damaged, even if the device is repeatedly operated after cell penetration.