In vitro study of ultrasound and different-concentration glycerol–induced changes in human skin optical attenuation assessed with optical coherence tomography

Abstract

Abstract. Previous studies have demonstrated the ultrasound-induced skin optical clearing enhancement with topical application of 60% glycerol ͑G͒ on in vitro porcine skin and in vivo human skin. Our purpose was to find the relation between the effect of optical skin clearing and different concentrations of glycerol and to find more effective ultrasound-glycerol combinations on optical skin clearing. The enhancement effect of ultrasound ͓Sonophoresis ͑SP͒ delivery͔ in combination with 40% G, 60% G, and 80% G on in vitro human skin optical clearing was investigated. Light imaging depths of skin were measured using optical coherence tomography. Different concentrations of glycerol and ultrasound with a frequency of 1 MHz and an intensity of 0.5 W / cm 2 was simultaneously applied for 15 min. The results show that with the increase of concentration of glycerol, the optical clearing of skin is much improved. Optical clearing capability of glycerol was more enhanced with simultaneous application of ultrasound compared with glycerol alone. The attenuation coefficients of skin tissues after application of 40% G/SP, 60% G/SP, and 80% G/SP decreased approximately 11.8%, 18.5%, and 20.0% at 15 min compared with 40% G, 60% G, and 80% G alone, respectively. The greatest decrease in attenuation coefficients at 60 min was approximately 52.3% and 63.4% for 80% G ͑without ultrasound͒ and 80% G/SP ͑with ultrasound͒, respectively, which are 2.1-fold and 2.6-fold to that in the 40% G.

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

“…The low-frequency US effect (sonophoresis) is one of the noninvasive methods of improving the clearing effect for many OCAs, increasing the depth and rate of their delivery into tissues [134,135,[165][166][167][168]. The combined use of OCA and US provided considerable increase of the depth and contrast of the OCT images of porcine skin in vitro and human skin in vivo [166].…”

“…Beside the chemical agents, a number of physical methods of surmounting the skin barrier are proposed to enhance the diffusion, including low-and high-intensity irradiation [130,158], fractional lamp [131,133] and laser [132] microablation, mechanical microperforation [137,138], ultrasonic (US) irradiation [134,135,159], electrophoresis [160], needleless injection [161], mechanical removal of the surface layer by means of abrasive paper [136], epidermal stripping [162], and microdermabrasion [163].…”

“…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.…”

Quantification of glucose and glycerol diffusion in myocardium

“…Most of them are overviewed in Refs. 3, 4, 11-17 and recent ones present optical clearing of tissues such as skin, [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] sclera, [33][34][35] and skeletal muscle. [36][37][38][39][40][41] We have found that only in two papers optical clearing of heart tissues were investigated.…”

OCT study of skin optical clearing with preliminary laser ablation of epidermis

“…However, the diffusion of immersion agents into the skin is hindered by the existence of epidermal barrier. To overcome the barrier function of the epidermis, different methods are used, including the chemical dissolving of the lipid layer [5,6], the mechanical damages [7], the effect of ultrasound [6][7][8][9], etc. Among these methods, the laser microablation of epidermis can be used to solve the problem.…”