A useful way to develop effective in vivo skin optical clearing agents

Abstract

Skin optical clearing has shown tremendous potential in improving various optical imaging performances, but there is some certain blindness in screening out high-efficiency in vivo optical clearing methods. In this work, three optical clearing agents: sucrose (Suc), fructose (Fruc) and PEG-400 (PEG), and two chemical penetration enhancers: propylene glycol (PG) and thiazone (Thiaz) were used. PEG was firstly mixed with the two penetration enhancers, respectively, and then mixed with Fruc and Suc, respectively, to obtain six kinds of skin optical clearing agents (SOCAs). Optical coherence tomography angiography was applied to monitor SOCAs-induced changes in imaging performances, skin optical properties, refractive index mismatching extent, and permeability rate. Experimental results demonstrated that PEG+Thiaz+Suc has the optimal capacity in enhancing the imaging performances, decreasing the scattering and the refractive index mismatching since Thiaz is superior to PG, and Suc is superior to Fruc. This study indicates that the optimal SOCA can be obtained directly by means of additionally adding or replacing the similar category substance in preexisting SOCAs with some more effective reagents. It not only provides an optimal SOCA, but also provides a useful way to develop more effective SOCAs. Cross-section skin structural texture (a), reconstructed blood flow distribution information (b), before or after treated with different SOCAs.

Visualization of skin microvascular dysfunction of type 1 diabetic mice using in vivo skin optical clearing method

“…Diabetes can accelerate inflammation of wound caused by the surgery, which may affect the vascular function. 42 Fortunately, in vivo skin optical clearing method developed recently, 41 as a low-cost and convenient method, provides a good way for studying skin microvascular hemodynamics under pathological conditions. Additionally, under the consistent experimental condition, we found that arteriovenous blood flow and blood oxygen saturation almost kept unchanged before and after injection of saline.…”

“…Here, we used the in vivo dorsal skin optical clearing method 41 to enhance the imaging qualities of LSCI and HSI. The dorsal skin optical clearing agent (DSOCA) was a mixture of PEG, thiazone, and sucrose [67.1% (wt./wt.)].…”

“…Then, the dorsal hair was shaved with electric hair clipper and the residual hair was removed thoroughly with local application of depilatory cream, this method of hair removal referenced to the reported work. 41 During the experiment, the mouse was placed on a heating pad for maintaining body temperature at 36.5°C to 37.5°C. To establish the optical clearing skin window, DSOCA was topically applied on the dorsal region of interest for 15 min; the treatment time of DSOCA was the same in all experiments.…”

“…Fortunately, in vivo skin optical clearing method has been developed and implemented in recent years, [26][27][28] which has excellently enhanced the imaging performances on various optical imaging modalities, including optical coherence tomography (OCT), [29][30][31] photoacoustic microscopy, 32,33 LSCI, [34][35][36][37][38][39] HSI, 40 and confocal microscopy. [41][42][43] In this study, based on the alloxan-induced type 1 diabetic (T1D) mice model, we evaluated NE-induced skin vascular responses (including blood flow and blood oxygen) along with the development of diabetes by LSCI and HSI, with the help of in vivo skin optical clearing method we developed previously. 41 …”

“…[41][42][43] In this study, based on the alloxan-induced type 1 diabetic (T1D) mice model, we evaluated NE-induced skin vascular responses (including blood flow and blood oxygen) along with the development of diabetes by LSCI and HSI, with the help of in vivo skin optical clearing method we developed previously. 41 …”