Different Molecular Interaction between Collagen and α- or β-Chitin in Mechanically Improved Electrospun Composite

Although collagens from vertebrates are mainly used in regenerative medicine, the most elusive issue in the collagen-based biomedical scaffolds is its insufficient mechanical strength. To solve this problem, electrospun collagen composites with chitins were prepared and molecular interactions which are the cause of the mechanical improvement in the composites were investigated by two-dimensional correlation spectroscopy (2DCOS). The electrospun collagen is composed of two kinds of polymorphs, alpha- and beta-chitin, showing different mechanical enhancement and molecular interactions due to different inherent configurations in the crystal structure, resulting in solvent and polymer susceptibility. The collagen/alpha-chitin has two distinctive phases in the composite, but beta-chitin composite has a relatively homogeneous phase. The beta-chitin composite showed better tensile strength with similar to 41% and similar to 14% higher strength compared to collagen and alpha-chitin composites, respectively, due to a favorable secondary interaction, i.e., inter- rather than intra-molecular hydrogen bonds. The revealed molecular interaction indicates that beta-chitin prefers to form inter-molecular hydrogen bonds with collagen by rearranging their uncrumpled crystalline regions, unlike alpha-chitin.