OCT monitoring of ex vivo and in vivo mice skin enhanced optical clearing by the biocompatible OCA mixtures

Abstract

Optical techniques applied to the skin providing a non-invasive and relatively fast analysis tool for getting access to morphology and optical properties of the biological tissue. Also, it was found that special biocompatible chemicals called Optical Clearing Agents (OCA) can penetrate through the skin and by dehydration, reversible collagen fibers dissociation and the refractive indices matching between intercellular and extracellular liquids may increase the depth and contrast of optical techniques. However, skin acts as the natural physiological barrier, preventing leaking in and out of the liquids, what makes it difficult to efficiently introduce the OCAs within the skin. One possible way to overcome the skin barrier for OCAs is their using in combination with the chemical and physical permeation enhancers that can create the pathways in upper skin layers, thus increasing the OCA penetration depth and speed. The goal of the study is to explore the effect of optical clearing by the biocompatible OCA mixtures combined with chemical and physical permeation enhancers on the contrast and optical depth of the OCT probing of mice skin in vivo and ex vivo.
In this work we used 5 different combinations of optical clearing agents and chemical permeation enhancers for increasing the optical depth of OCT probing in 2 different conditions (in vivo and ex vivo): mixture of aqueous sucrose solution, DMSO and distilled water in ratio 50:45,5:4,5; mixture of oleic acid (OA) and PEG-400 in ratio 20:80; mixture of aqueous sucrose solution, PEG-400 and PG in ratio 50:45:5; mixture of aqueous solution of Hyaluronic Acid and PEG - 400 in ratio 20:80; mixture of aqueous sucrose solution, PG and OA in ratio 50:42,56:7,44. All mixtures used met the FDA maximum concentration requirements for use on the skin. Sixteen albino laboratory mice were used in this study. Dermabrasion was applied to the skin as physical permeation enhancer before the mixture application. Mechanical massage was used to enhance the penetration of chemicals. Optical Coherence Tomography (OCT) was used to measure the changes in vivo and ex vivo in skin contrast and optical depth of the OCT probing.

This work was supported by RFBR (projects number 20-32-90043 and 20-52-56005).


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Speaker

Sergey M. Zaycev
Saratov State University, Russian Federation; Université de Lorraine, France
Russia

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