Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo

Abstract

In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing. Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thiazone (0.25%T); (4) 0.25% thiazone and 5-min ultrasound (0.25%T/SP). The diffuse reflectance spectra and imaging depth of human skin in vivo at different times were measured by spectroscopy and optical coherence tomography (OCT). The optical clearing efficacy of skin was qualitatively and quantitatively analyzed. The results showed that the diffuse reflectance at 540 nm of samples at 10 min after being treated by 0.25%T/SP decreased by approximately 15.51%, whereas, 0.46%, 4.73% and 5.75% were received in C, PEG400 and 0.25%T, respectively. And at 60 min, the decrease in diffuse reflectance of samples in 0.25%T/SP is about 2.22-fold, 1.20-fold compared with that of the samples in PEG 400 and 0.25%T, at 540 nm, respectively. Simultaneously, 0.25%T/SP results in 41.33% increase in OCT 1/e light penetration depth after 60 min. There was a significant difference in the optical clearing effect on skin between ultrasound-mixed solution of thiazone in combination with PEG 400 and the mixed solution (P < 0.05).

Optical clearing of biological tissues: prospects of application in medical diagnostics and phototherapy

“…The US processing was also used in combination with Thiazone to improve the penetration of PEG-400 into the skin [149]. It was shown that after the complex processing with Thiazone, PEG-400, and US the diffuse reflection coefficient decreased by 33.7 folds as compared to the control measurements (without clearing).…”

“…The combined use of chemical and physical OCA diffusion enhancers facilitates further increase of the optical clearing efficiency [118,148,149]. Thus, Xu et al [148] showed that the sodium lauryl sulphate, a surface-active agent often used as an enhancer of penetration of pharmaceutic and cosmetic products into skin, in combination with the US demonstrates a synergetic enhancing effect on the penetration of 60% glycerol solution into the skin.…”

“…In particular, it is shown that Azone [141], oleic acid [142], DMSO [118,[143][144][145][146], ethanol [150], propylene glycol [147,151], Thiazone [149] enhance the tissue permeability for OCAs and increase the efficiency of optical clearing.…”

“…However, at low concentrations OCAs do not provide sufficient optical clearing, while at high concentrations they can induce edema, chemical burn, partial necrosis and scarring [45,65,108]. To develop an efficient and safe way of breaking the integrity of the epidermis stratum corneum and accelerating the penetration of OCA into the dermis, various physical methods [56,118,[130][131][132][133][134][135][136][137][138][139][140], chemical enhancers of permeability [114,118,[141][142][143][144][145][146][147], and their combinations [118,148,149] have been proposed.…”

Optical clearing in photoacoustic flow cytometry

“…There are more than thirty chemical peels for dermatology and cosmetology, and more than ten of them are applied together with lasers [36][37][38][39][40]. Diffusion through skin may be enhanced by sonophoresis (phonophoresis), electrophoresis (iontophoresis), external pressure, and massage [20,[41][42][43][44][45][46]. The major advantage of these methods is considerable reduction of treatment time from hours down to several ten minutes [41,[47][48][49][50][51][52][53][54][55][56].…”