Charged microbeads are not transported across the human stratum corneum invitro by short high-voltage pulses

There have been several reports of particle transport due to high-voltage p ulsing of human skin. Here, several different short, high-voltage pulsing p rotocols were used in vitro to study the possible transport of highly charg ed, fluorescent polystyrene particles (14 nm to 2.1 mu m in diameter; surfa ce charges of -4.05 x 10(3) e to -2.77 X 10(7) e) across the skin. Two diff erent methods were used to trap and measure particles on the other side of the skin. The first used a polycarbonate membrane to trap the particles, de termining the amount of transport by enumeration under a fluorescence micro scope. The second used spectrofluorimetry to measure the amount of particle s transported. After pulsing, particles were found in randomly distributed clusters on the surface of the skin. No detectable transport across the str atum corneum for any size particle was observed. (C) 1999 Elsevier Science S.A. All rights reserved.