During aging, the skin undergoes a degradation of its biomechanical properties, and in particular a loss of elasticity which leads to sagging skin. The elastic fibers of the dermis are the main elements that give the skin its elasticity and resilience. But over time, their organization and functionality deteriorate, making them a key target in anti-aging cosmetic strategies.
Skin substitutes developed by tissue bioengineering, readily available on the market today, remain imperfect models for studying skin elasticity. Indeed, they contain exogenous and artificial supports which bias the measurement of the biomechanical properties in said tissues. The development of a suitable model to mechanically study a tissue structure like that of the skin was therefore necessary.
Gattefossé laboratories have developed a new model of dermal micro-tissue which does away with culture matrices to allow in vitro measurement of the intrinsic elastic properties of the dermis. To assess the elasticity of these skin micro-tissues called spheroids, Gattefossé chose BioMeca's expertise to conduct an innovative analytical assessment with cutting-edge technologies.
“Characterizing biological models to assess the effect of active ingredients and cosmetic products on restoring and maintaining skin homeostasis is essential today. BioMeca offers cutting-edge technologies to meet the challenges of skin biology. Under quasi-physiological conditions and over time, second harmonic microscopy brings to light and images the fibrous networks while atomic force microscopy makes it possible to assess the stiffness of the tissues. Topographic and mechanical studies, quantification and nanomechanical characterization of tissues, BioMeca's expertise is a key to exploring the elastic properties of skin models and opens the doors to a better understanding of the biomechanics of the skin ” , emphasizes Julien Chlasta, co-founder and president of BioMeca.
Spheroid culture has the advantage of using the capacity of cells to secrete their own extracellular matrix, in order to produce their own tissue microenvironment in vitro. This technology has enabled Gattefossé to produce hundreds of microtissues in vitro in a few days, from dermal fibroblasts cultured in plates with very low cell adhesion. The elastic modulus (or Young's modulus) could then be quantified by atomic force microscopy (AFM) and the elastic fibers visualized by second harmonic generation (SHG) microscopy. Gattefossé and BioMeca have thus demonstrated the reliability and relevance of this micro-tissue model, the complex organization of which forms a dense network of mature elastic fibers large enough to model dermal elastic mechanics in vitro.
The development of the spheroid micro-tissue model was presented at the end of 2020 at the 31st Congress of the IFSCC in Yokohama.
"By combining two state-of-the-art analytical techniques, second harmonic generation microscopy (SHG) and atomic force microscopy (AFM), we accurately correlated the presence and quantity of elastic fibers with the elastic properties of micro-tissues, demonstrating that newly formed elastic fibers were functional,"said Dr. HDR Nicolas Bechetoille, Who was responsible for skin biology research.
This skin micro-tissue model was used to measure the effectiveness of EleVastin, the new cosmetic active ingredient developed by Gattefossé, combating sagging skin, which will be launched in April 2021.