Design and Evaluation of a Bilayered Dermal/Hypodermal 3D Model Using a Biomimetic Hydrogel Formulation

Due to the limitations of the current skin wound treatments, it is highly valuable to have a wound healing formulation that mimics the extracellular matrix (ECM) and mechanical properties of natural skin tissue. Here, a novel biomimetic hydrogel formulation has been developed based on an Agarose-Collagen Type I (AC) blend combined with skin ECMrelated components: Dermatan sulphate (DS), Hyaluronic acid (HA), and Elastin (EL) for its application in skin tissue engineering (TE). Different formulations were elaborated based on AC hydrogel combined with DS, HA and EL. Cell viability, physicochemical, mechanical, and wound healing properties were investigated. Finally, a bilayered hydrogel loaded with fibroblasts and mesenchymal stem cells have been developed using the ACDHE formulation. The ACDHE hydrogel displays the best in vitro results and acceptable physicochemical properties. Also, it shows to be mechanically close to human native skin. Moreover, the bilayered cell-loaded hydrogel exhibits good cytocompatibility. ESEM analysis revealed a porous microstructure that allows maintaining cell growth and ECM-like structure production. These findings demonstrate the potential of the ACDHE hydrogel formulation for applications such as an injectable hydrogel or a bioink to create cell-laden structures for skin TE.Funding Information: This research was supported by MINECO MAT 2016-78778-R and PCIN-2015-051 projects (Spain), European Regional Development Fund (ERDF), by the Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía and European Regional Development Fund (ERDF), projects B-CTS-230-UGR18, PY18-2470, A-CTS-180-UGR20, SOMM17-6109, and P18-FR-2465), by the Fundación Mutua Madrileña (project FMM AP17196-2019) and by and by the Ministry of Economy and Competitiveness, Instituto de Salud Carlos III, ERDF funds (DTS21/00098 and DTS19/00145). Declaration of Interests: PGM is employed at Bioiberica SAU. The rest of authors declare no conflict of interest. Ethical Approval Statement: All human samples used in this study were obtained after informed consent (Hospital Vithas, Granada, Spain) and authorization was provided from the Granada Provincial Ethics Committee (Ministry of Health and Families, Andalusia, Spain, reference: 0467-N-20).