Ultrastructural Analysis of In Vitro Glycated Engineered Skin

Aging of the human skin results in undesirable physical properties such as wrinkles, yellowing, and loss of luster. Advanced glycation end-products (AGEs) are understood to be one of the primary causes for these effects as assessed from studies on human skin subjected to in vivo or in vitro mediated glycation. Models to recapitulate the effect of skin-glycation in vitro are an active area of interest to understand and mitigate these effects. In this regard, engineered skin models have utilized pre-glycated collagen to assemble a glycated skin layer. However, this method is time-consuming and can suffer from variability across samples. The objective of this study was to examine how in vitro glycation of an engineered skin model affects its material properties.

In this study we used a pre-engineered skin model (MatTek EpiDerm) and subjected it to in vitro glycation using glyceraldehyde. The changes in luminosity of the samples were characterized 48 h post-glycation. Immunohistochemistry using an anti-AGE antibody was performed to verify glycation of the samples. Scanning transmission electron microscopy (STEM) and atomic force microscopy (AFM) were used to assess the ultrastructure of the samples and evaluate their surface roughness, adhesion, and mechanical properties.

Our results show that upon glycation the engineered skin had reduced luster, increased yellowing, disruption in cell and matrix morphology, increased roughness, and modulus. These effects are similar to those previously reported in both natural and engineered skin.

Overall, the approach presented here serves as a quick and easy method to recapitulate the glycation induced effects in the model skin and can serve as a platform to evaluate the effect of skin-care products on mitigating these effects.