Biodegradable conductive IPN in situ cryogels with anisotropic microchannels and sequential delivery of dual-growth factors for skeletal muscle regeneration

Abstract

Biodegradable and anisotropic cryogels that simulate conductivity and ECM orientation structure of skeletal muscle, and release multiple growth factors, are expected for in situ skeletal muscle tissue engineering. Herein, biodegradable, conductive and anisotropic interpenetrating network (IPN) in situ cryogels are fabricated through Schiff base/acylhydrazone crosslinking via combining unidirectional freezing and cyclic freeze-thaw processes. The cryogels have good anisotropic mechanical properties and oriented microchannel structure, and induce the oriented alignment of myoblasts. The introduction of aniline tetramer enhances the mechanical properties and conductivity of the cryogels. The conductive cryogels significantly improve the proliferation and myogenic differentiation of C2C12 cells during 3D culture. The sequential delivery of insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) can induce migration of human umbilical vein endothelial cells (HUVECs), proliferation of human skin myofibroblasts (HMFB), and myogenic differentiation of C2C12 cells in vitro. In particular, conductive and anisotropic cryogels with dual-growth factors can significantly improve the repair efficiency of volumetric muscle loss (VML) in vivo. This study provides a new strategy to fabricate anisotropic and conductive IPN in situ cryogel biomimetic scaffolds that can encapsulate dual-growth factors and deliver them in time sequence, which significantly promote the efficient repair of VML via an in situ tissue engineering approach.