Assessment of the effects of ultrasound-mediated alcohols on skin optical clearing

Abstract

Our previous studies have shown the ultrasound-induced skin optical clearing enhancement with topical application of glycerol on in vitro porcine skin and in vivo human skin. The objective of this study was to find more effective ultrasound-alcohol combinations on skin optical clearing. The effect of sonophoretic delivery (SP) in combination with a series of alcohols such as glycerol, propylene glycol, butanediol, butanol, polyethylene glycol (PEG200, PEG400) on skin optical clearing was investigated. Light transmittance and imaging depth of in vitro porcine skin were measured with spectroscopy and optical coherence tomography (OCT). Sixty percent alcohols and ultrasound (SP) with a frequency of 1MHz and a power of 0.75W over a 3-cm probe was simultaneously applied for 15min. Optical clearing capability of alcohols was much improved with the simultaneous application of ultrasound compared with alcohols alone. Light transmittance at 1276nm increased by 31% (butanol) to 57% (PEG200) at 60min, respectively. PEG200 with ultrasound exhibited 1.8-fold the clearing capability of PEG200 alone, which was the highest enhancement by ultrasound among the six alcohols. Sixty minutes of PEG200/SP exposure resulted in a significantly increased 1/e light penetration depth of 1.43mm compared to 0.95mm for control in OCT measurement. © 2009 Society of Photo-Optical Instrumentation Engineers.