A mimicked collagen layer/silk fibroin film as a cardio patch scaffold

The aim of this study was to evaluate immobilisation and structural formation of mimicked self-assembled collagen on Bombyx mori silk films for use as a biomedical material. Three concentrations (0.5, 1 and 2 mg/ml) of type Icollagen were mixed with phosphate-buffered saline (PBS, pH 7). The mixture of type I collagen and PBS (biomimetic mixture) was immobilised on modified silk films with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. The morphological and topographical characteristics observed using scanning electron microscopy and atomic force microscopy showed that as collagen concentrations increased, fibrils organised themselves into irregular structures as clusters of twisted fibrils. The structural formation of collagen immobilisation was determined using a Fourier transform infrared spectroscopy (FTIR). The FTIR spectra showed that both silk and collagens (amides I, II, III, A and B) were assigned to beta-sheet conformation of silk fibroins and collagen type I. Hydrophobic and hydrophilic group functionalities of silk fibroin films were characterised by contact angle measurement, which demonstrated that immobilised silk fibroin films had low hydrophilic group functionality.