Immersion skin clearing with aqueous urea solution: OCT data and molecular modeling
E. Yu. Stepanovich 1, K. V. Berezin 2, A. M. Likhter 1, K. N. Dvoretsky 3, E. V. Grabarchuk 1, I. Yu. Yanina 2.4, V. V. Tuchin 2.4.5
1 Astrakhan State University, 414056 Astrakhan, Russia
2 Saratov State National Research University, 410012 Saratov, Russia
3 Saratov State Medical University, 410012 Saratov, Russia
4 National Research Tomsk State University, 634050 Tomsk, Russia
5 Institute of Precision Mechanics and Control, Federal Research Center "Saratov Scientific Center of the Russian Academy of Sciences," 410028 Saratov, Russia
Abstract
Using optical coherence tomography (OCT), the results of immersion optical clearing of human skin in vivo were obtained, with a 50% aqueous urea solution used as the immersion agent. To evaluate the efficiency of optical clearing, the rates of change in the light scattering coefficient were determined based on averaged A-scans of the OCT signal in the dermis region at a depth of 350 to 700 µm. As a result of full-atom molecular dynamics simulations (GROMACS), the effect of a 50% aqueous urea solution on the spatial volume of a collagen microfibril fragment, 5((GPH)₁₂)₃, was determined. Using quantum chemical methods (HF/STO-3G, DFT/B3LYP/6-311G(d)), the intermolecular interaction energy in the urea-collagen peptide fragment ((GPH)₃)₂ complex was calculated, and the parameters of the regression equation linking the optical clearing efficiency with the intermolecular interaction energy were refined. The thermodynamics of hydrogen bonds formed during the interaction of urea with the collagen peptide and water molecules are discussed.
Speaker
Ekaterina Yu. Stepanovich
Astrakhan State University
Russia
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