The possibility of using silica-gold nanoshells with 150 nm silica core size and 25 nm thick gold shell as contrasting agents for optical coherence tomography (OCT) is analyzed. Experiments on agar biotissue phantoms showed that the penetration of nanoshells into the phantoms increases the intensity of the optical coherence tomography (OCT) signal and the brightness of the corresponding areas of the OCT image. In vivo experiments on rabbit skin demonstrated that the application of nanoshells onto the skin provides significant contrasting of the borders between the areas containing nanoshells and those without. This effect of nanoshells on skin in vivo is manifested by the increase in intensity of the OCT signal in superficial parts of the skin, boundary contrast between superficial and deep dermis and contrast of hair follicles and glands. The presence of nanoshells in the skin was confirmed by electron microscopy. Monte Carlo simulations of OCT images confirmed the possibility of contrasting skin-layer borders and structures by the application of gold nanoshells. The Monte Carlo simulations were performed for two skin models and exhibit effects of nanoparticles similar to those obtained in the experimental part of the study, thus proving that the effects originate exactly from the presence of nanoparticles.

Modern optical diagnostic techniques often require deformations of the studied bio-tissues for image acquisition. This paper discusses the effect of mechanical compression on the formation of OCT images of human skin. The study was performed in vivo on human volunteers of different age. We show that application of compression to human skin induces changes in optical properties of the sample associated with elasticity of different skin layers. These changes induce an increase in the contrast of interlayer boundaries. Further application of compression causes the appearance of dark areas in the OCT images obtained, likely associated with interstitial or intracellular water inflow to the observed region. The effects studied are of importance for proper interpretation of obtained OCT images in diagnosis of skin pathologies.

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The current work is concerned with investigation of age-specific morpho-functional parameters of skin of different localizations.