Preparation of Collagen/Aspartic Acid Nanocomposite Fibers and Their Self-Assembly Behaviors

Collagen is a promising biomaterial with excellent biocompatibility, low immunogenicity, and good biodegradability. However, the poor mechanical properties of regenerated collagen fibers, which are susceptible to thermal denaturation and rapid degradation, remain a substantial challenge. In this work, aspartic acid (Asp) was incorporated to improve the performance of collagen fibers. The self-assembly behavior of collagen molecules in the presence of Asp was investigated, and the structure and properties of the collagen/Asp composite fibers were discussed. Their results showed that there are strong molecular interactions between the negatively charged Asp and the positively charged collagen molecules in acidic conditions. The mechanical properties and thermal stability of composite fibers are significantly improved compared with those of pure collagen fibers. Electrostatic interactions are the main factors affecting the self-assembly structure of collagen molecules, the alignment of collagen microfibrils, and the mechanical and thermal performances of composite fibers. This work provides a simple and environmentally friendly pathway to generate collagen-based fiber materials with better properties and has the potential to be used in a variety of biomedical applications.