Modification of collagen and chitosan mixtures by the addition of tannic acid

The properties of collagen/chitosan mixtures with weight ratios: 75/25, 50/50, and 25/75 were modified by the addition of tannic acid. Tannic acid was added in the ratios 2, 5, 10 and 20 wt.% based on chitosan. Molecular interactions between the components and structure of the blends were studied by Fourier transform infrared spectroscopy (FTIR). Mechanical properties were measured by a mechanical testing machine. Swelling behavior was measured by immersing the fragments of the blend in phosphate-buffer saline. Infrared spectroscopy showed that cross-linking process by tannic acid occurred in collagen/chitosan mixtures. It was found that compressive modulus decreased with increasing amount of tannic acid in chitosan/collagen blends. Addition of tannic acid improved swelling behavior of those mixtures where collagen was in predominance. The modification of collagen/chitosan mixture using tannic acid can lead to new bespoke materials for potential biomedical applications.