Peripheral nerve regeneration with 3D printed bionic double-network conductive scaffold based on GelMA/chitosan/polypyrrole.

Peripheral nerve injury (PNI) is a serious condition with limited surgical treatment options available. Conductive hydrogels have emerged as a promising alternative due to their ability to facilitate electrical signal exchange between cells and replicate the physiological microenvironment of electroactive tissues. Three-dimensional (3D) printing offers an innovative approach for fabricating neural scaffolds with precise structures and complex spatial architectures. In this study, we introduce a novel dual-bioink 3D printing strategy that integrates synthetic and natural materials to construct stable biomimetic neural tissue structures. The base bioink, comprising gelatin methacrylate (GelMA), chitosan (CS), and the conductive polymer polypyrrole (PPy), serves as a physical support network. It offers conductive pathways, promote cell growth, and ensures long-term structural integrity. The secondary bioink is a cell-loaded biodegradable gel-gelatin, which enables for precise cell deposition within the base network through a hybrid printing technique. The composite scaffold was evaluated for its mechanical properties, cytotoxicity, and ability to support neural differentiation. The results demonstrated that the 3D-printed neural network scaffold effectively promoted the neural differentiation and axon regeneration of PC-12 cells and HT-22 cells. These findings highlight its strong potential for facilitating neural functional recovery, positioning it as a promising candidate material for the treatment of PNI patients.