Optical investigation of three‐dimensional human skin equivalents: A pilot study

Human skin equivalents (HSEs) are three‐dimensional living models of human skin that are prepared in vitro by seeding cells onto an appropriate scaffold. They recreate the structure and biological behaviour of real skin, allowing the investigation of processes such as keratinocyte differentiation and interactions between the dermal and epidermal layers. However, for wider applications, their optical and mechanical properties should also replicate those of real skin. We therefore conducted a pilot study to investigate the optical properties of HSEs. We compared Monte Carlo simulations of (a) real human skin and (b) two‐layer optical models of HSEs with (c) experimental measurements of transmittance through HSE samples. The skin layers were described using a hybrid collection of optical attenuation coefficients. A linear relationship was observed between the simulations and experiments. For samples thinner than 0.5 mm, an exponential increase in detected power was observed due to fewer instances of absorption and scattering. Human skin equivalents are living cultures of skin tissue, grown by seeding fibroblasts and keratinocytes on a scaffold. Although devoid of chromophores, skin models are used to investigate the interactions between the epidermis and dermis, and the morphology of skin layers. This article describes Monte Carlo simulations and experiments involving two‐layer skin models. The measurements were comparable to the simulations, but only for samples thinner than 1 mm.