Covalently conjugated polypyrrole-chitosan nanofibrous conductive composites prepared using dialdehyde polysaccharide linkers

Abstract

Polypyrrole (PPy) composites, despite their conductivity and bioactivity, are prone to degradation (e.g., exfoliation or delamination) due to the lack of chemical bonds between PPy and the matrix. Rather than suppressing this degradation through laborious methods involving toxic organic linkers or custom pyrrole derivatives to achieve covalently bonded PPy composites, this study introduces a novel polysaccharide-based approach. This method uses dialdehyde polysaccharides (DAPs) to conjugate PPy to chitosan nanofibers (CHITs) covalently. DAPs stabilize CHITs through Schiff base chemistry and then conjugate pyrrole via aldol condensation. During subsequent polymerization, the conjugated pyrrole is incorporated into the PPy layer formed around the CHITs, covalently linking both polymers. The resulting composites exhibit good conductivity and cytocompatibility, making them promising for biomedical applications and tissue engineering. Moreover, this method is not limited to chitosan but can be extended to other amine-containing substrates.