Enhancement of transepidermal skin clearing agent delivery using a 980 nm diode laser

Background and Objectives: Patient compliant optical skin clearing requires non-invasive topical delivery of clearing agents such as glycerol. This requires reducing the skin barrier function by disrupting stratum corneum integrity, which was achieved using a 980 nm diode laser with artificial absorption substrates on the skin surface. Reduction of light scattering has the potential to improve many current and novel diagnostic and therapeutic applications of lasers in medicine. Study Design/Materials and Methods: In vivo hamster and rat skin was used to test optical skin clearing. Absorption substrates were applied to the skin after shaving. These included black ink, dark children's rub-on tattoo, and carbon paper. 980 nm cw laser light was used to ablate these substrates and to heat the skin surface to enhance the diffusion of topically applied glycerol for optical skin clearing. Increased light penetration was determined from amplitude optical coherence tomography data. Results: Results indicate an improvement of the ability to measure an OCT signal at a wavelength of 1,290 nm up to 42% deeper into in vivo rodent skin using a 980 nm laser with a fluence of less than 0.96 J/mm(2) to alter the stratum corneum. Conclusions: The use of an inexpensive diode laser can significantly enhance the delivery of topically applied glycerol for optical skin clearing. The laser use involves application of an absorption substrate onto the skin surface. Using carbon paper left no unwanted residue behind and is considered optimal for this purpose.