During aging, human skin undergoes profound alterations of its biomechanical properties, and more particularly a loss of elasticity that results in skin sagging. Dermal elastic fibers represent the primary components that support tissue compliance and resilience. But as time goes by, their organization and functionality decline, which makes them a preferred target for cosmetic anti-aging strategies. The current 3D bioengineered skin substitutes, which are easily available on the market, are still defective models to study skin elasticity. Indeed, they contain exogenous and artificial matrices that bias the measurement of biomechanical properties in the reconstructed tissue. So, there is a need to develop advanced models to investigate the mechanical structure of a tissue such as human skin.
3D scaffold-free microtissues were developed by Gattefossé laboratories to mimic in vitro an elastic tissue, which is responsible for intrinsic elastic properties of the dermis. To accurately evaluate the elasticity of such skin microtissues, Gattefossé chose BioMeca’s expertise for developing innovative analytical assessments with state-of-the-art technologies.
“Characterizing biological models is becoming a challenge to evaluate new formulas or active ingredients aiming to restore or maintain skin integrity. BioMeca offers state-of-the-art technologies to bring new insights biology. Second Generation Harmonic microscopy highlights fibers network while Atomic Force Microscopy reveals tissue stiffness in both imaging and mechanically manipulating biological structures near physiological conditions overtime. With topographical mechanical measurement, quantitative nanomechanical quantification and tissue characterization, BioMeca’s expertise represents a key for exploring elastic properties of skin models and opens a new door for skin care.” underlined the co-Founder of BioMeca, Julien Chlasta.
3D scaffold-free spheroids take advantage of the ability of cells to secrete their own extracellular matrix to ultimately recreate their own microenvironment. This technology enabled Gattefossé to produce in vitro hundreds of 3D microtissues within a few days only using dermal fibroblasts aggregated in ultra-low affinity plates.
The elastic modulus (or Young modulus) was then measured using Atomic Force Microscopy (AFM) and the elastic fibers were visualized by Second Harmonic Generation (SHG) imaging microscopy. Gattefossé and BioMeca thus demonstrated that the 3D spheroid microtissue is a relevant and reliable model with a complex organization, comprising a dense, mature elastic fiber network sufficiently extensive to mimic in vitro dermal elastic mechanics.
This investigative approach has been featured at the 31st IFSCC Congress, in Yokohama late in 2020.
“By combining two cutting-edge analytical techniques, i.e., second harmonic generation (SHG) microscopy and atomic force microscopy (AFM), we have been able to accurately correlate both the presence and amounts of elastic fibers with elastic properties of microtissues,
thus evidencing that newly formed elastic fibers were functional” said the Skin Biology Research Manager at Gattefossé, Dr HDR Nicolas Bechetoille.
This advanced 3D model has been successfully used to measure the efficacy of EleVastinTM a novel active ingredient developed by Gattefossé, fighting against age related loss of skin elasticity. More to come in April 2021.