3D-bioprinted human lipoaspirate-derived cellladen skin constructs for healing of full-thickness skin defects

29Three-dimensional (3D)-printed bioactive scaffolds that can be produced rapidly could offer an individualized approach for treating full-thickness skin defects. Decellularized extracellular matrix (dECM) and mesenchymal stem cells have been proven to support wound healing. Adipose tissues obtained by liposuction are rich in adipose-derived dECM (adECM) and adipose-derived stem cells (ADSCs) and thus represent a natural source of bioactive materials for 3D bioprinting. Herein, ADSC-laden 3D-printed bioactive scaffolds consisting of gelatin methacryloyl (GelMA), hyaluronic acid methacryloyl (HAMA), and adECM were fabricated with dual properties of photocrosslinking in vitro and thermosensitive crosslinking in vivo. adECM was prepared by decellularization of human lipoaspirate and mixed as a bioactive material with GelMA and HAMA to form a bioink. Compared with the GelMA-HAMA bioink, the adECM-GelMA-HAMA bioink had better wettability, degradability, and cytocompatibility. Full-thickness skin defect healing in a nude mouse model showed that ADSC-laden adECM-GelMA-HAMA scaffolds accelerated wound healing by promoting faster neovascularization, collagen secretion, and remodeling. ADSCs and adECM collectively conferred bioactivity on the prepared bioink. This study represents a novel approach to enhancing the biological activity of 3D-bioprinted skin substitutes by adding adECM and ADSCs derived from human lipoaspirate and may provide a promising therapeutic option for full-thickness skin defects.