Silk fibroin/gelatin multilayered films as a model system for controlled drug release

Multilayer films based on silk fibroin protein and gelatin was fabricated in aqueous solution for controlled drug release. The gradual build up of layer was investigated by UV-vis spectroscopy and was further analyzed through attenuated total reflectance-Fourier transform infrared spectroscopy. Scanning electron microscopy confirmed the presence of distinct layers within the multilayer system. Intervening dehydrating step by methanol treatment was used to control the structure and stability of the self-assembled silk fibroin/gelatin multilayer films. The films were tested for in vitro release using three different molecular weight model compounds namely trypan blue (961 Da), FITC-inulin (3.9 kDa) and FITC-BSA (66 kDa). The release profile of compounds revealed dependence on multilayer film degradation for sustained release. The release kinetics was further evaluated as a function of gelatin and buildup of layers suggesting their possible role in restricting initial burst leading to sustained compound release. MTT and confocal microscopy were used to assess cellular viability and biocompatibility of fabricated films using fibroblast cells. The results highlight the versatile and tunable properties of fibroin/gelatin multilayer films making them exciting candidates for the controlled release of a wide spectrum of bioactive molecules.