Microfabrication of individual 200 mu m diameter transdermal microconduitsusing high voltage pulsing in salicylic acid and benzoic acid

We describe an extension of semiconductor fabrication methods that creates individual approximate to 200 mum diameter aqueous pathways through human s tratum corneum at predetermined sites. Our hypothesis is that spatially loc alized electroporation of the multilamellar lipid bilayer membranes provide s rapid delivery of salicylic acid to the keratin within corneocytes, leadi ng to localized keratin disruption and then to a microconduit. A microcondu it penetrating the isolated stratum corneum supports volumetric flow of ord er 0.01 ml per s with a pressure difference of only 0.01 atm (about 10(2) P a). This study provides a method for rapidly microengineering a pathway in the skin to interface future devices for transdermal drug delivery and samp ling of biologically relevant fluids.