3D-Bioprinted Biomimetic Multilayer Implants Comprising Microfragmented Adipose Extracellular Matrix and Cells Improve Wound Healing in a Murine Model of Full-Thickness Skin Defects

Repairing full-thickness skin defects is a major challenge in clinical practice. Three-dimensional (3D) bioprinting of living cells and biomaterials is a promising technique to resolve this challenge. However, the time-consuming preparation and limited sources of biomaterials are bottlenecks that must be addressed. Therefore, we developed a simple and fast method to directly process adipose tissue into a microfragmented adipose extracellular matrix (mFAECM) as the main component of bioink to fabricate 3D-bioprinted, biomimetic, multilayer implants. The mFAECM retained most of the collagen and sulfated glycosaminoglycans in the native tissue. In vitro, the mFAECM composite demonstrated biocompatibility, printability, and fidelity and could support cell adhesion. In a full-thickness skin defect model in nude mice, cells encapsulated in the implant survived and participated in wound repair after implantation. The basic structures of the implant were maintained throughout wound healing and gradually metabolized. The biomimetic multilayer implants fabricated via mFAECM composite bioinks and cells could accelerate wound healing by promoting the contraction of new tissue inside the wound, collagen secretion and remodeling, and neovascularization. This study provides an approach for improving the timeliness of fabricating 3D-bioprinted skin substitutes and may offer a useful tool for treating full-thickness skin defects.