In vivo electroporation. first reported in 1987, makes it possible to rende
r cell membranes temporarily permeable to substances that otherwise would n
ot be able to effectively enter the cell interior. Micro- or millisecond pu
lses of electrical field strengths exceeding the natural cellular transmemb
rane potential difference of approximately 1 V results in permeabilization
("poration") of cell membranes. This phenomenon opens up numerous applicati
ons in the medical field. Electroporative delivery of chemotherapeutic drug
s into tumor cells has proven successful in clinical studies to treat malig
nant tumors and is nearing market introduction in Europe. For gene therapy
applications, delivery of DNA by electroporation into a variety of tissues
has been shown to consistently result in a 100-1000-fold enhancement of gen
e expression. Other applications of electroporation discussed in this paper
include intravascular delivery of drugs and genes with electroporation cat
heters, electroinsertion of molecules into membranes, intraocular delivery
of drugs and genes, and transdermal drug delivery. The use of electroporati
on for drug and gene delivery in vivo is clearly gaining momentum, and new
medical applications are emerging at an increasing rate.