Injectable PEDOT:PSS-conductive hydrogel based on marine polysaccharides for peripheral nerve repair

The repair of peripheral nerve injuries remains a major challenge in the field of tissue engineering. Electrical signals play a crucial role in the process of nerve regeneration, making the development of biomimetic materials with excellent conductivity and biocompatibility highly significant for neural tissue repair. In this study, a three-dimensional network hydrogel CMOS was prepared based on marine polysaccharide carboxymethyl chitosan (CMCS) and oxidized alginate sodium (OSA), and its electrical conductivity was enhanced by doping different volume fractions (1 %, 3 %, 5 %) of conductive polymer PEDOT:PSS. This dual-component design synergistically combines the intrinsic bioactivity of marine polysaccharides with the electrical functionality of PEDOT:PSS, addressing two key limitations of conventional hydrogels: poor bioactivity and insufficient conductivity. The resulting conductive hydrogels exhibited good gelation capability and favorable swelling behavior. Electrochemical analyses confirmed that the incorporation of PEDOT:PSS significantly enhanced the electrical conductivity of the hydrogel. In vitro cell experiments demonstrated that the hydrogels were biocompatible with PC12 cells, with the 3 % PEDOT:PSS group (CMOS/P3) achieving an optimal balance between conductivity and cellular activity. Moreover, the hydrogel displayed excellent injectability and biodegradability. When injected into the site of sciatic nerve crush injury, CMOS/P3 promoted the expression of key neural regeneration markers NF200 and S100, and alleviated gastrocnemius muscle atrophy. In conclusion, this marine polysaccharide-based PEDOT:PSS conductive hydrogel provides a promising injectable biomimetic platform for peripheral nerve regeneration.