Fully and spontaneously degradable carboxymethyl chitosan/oxidized hyaluronic acid-based membrane promoting three-dimensional tissue remodeling in vitro and in vivo

Remodeling three-dimensional (3D) tissues presents a significant challenge in the treatment of damaged body tissues. Although stem cell-based therapies show promise, current delivery strategies-such as cell sheets, pre-formed constructs, and conventional scaffolds-often face limitations due to complex fabrication processes, prolonged in vitro culture, unsustainable mechanical properties, and non-degradable materials that hinder cell-to-cell communication and complete tissue integration. In this study, we present a fully degradable polysaccharide composite membrane developed through the lyophilization of a self-crosslinking hydrogel, prepared via a Schiff base reaction between carboxymethyl chitosan (CMCTS) and oxidized hyaluronic acid (oHA). Physicochemical analyses confirmed successful synthesis of both the hydrogel and membrane, revealing adequate mechanical properties for cell loading, self-healing capabilities, and controlled degradability. Following fabrication, high-density stem cells from the apical papilla (SCAPs) were loaded onto the composite membrane. In vitro studies demonstrated excellent cell viability, facilitating cell condensation into a 3D aggregate architecture. Finally, direct implantation into a mouse subcutaneous model validated the membrane's efficacy as a delivery vehicle for SCAPs, promoting spontaneous tissue integration in situ. This study provides proof of concept for the in situ composite membrane as an efficient and straightforward platform for the immediate implantation of primary stem cells and 3D tissue remodelling.