Silk fibroin/sericin native blends as potential biomaterial templates

The silk produced by the domesticated silkworm (Bombyx mori) consists of two major polypeptidic components, fibroin and sericin. Both are used as biomaterial templates in tissue engineering applications, with variable success. While fibroin membranes are mechanically strong, they do not promote satisfactorily attachment and proliferation of cells. Sericin membranes display a precisely opposite behavior. In order to generate silk–based templates with optimal cell–adhesive properties and acceptable mechanical strength, we propose a method to manufacture fibroin/sericin blends in one single step, by processing the whole silk cocoons. The membranes prepared from these “native” blends were physically characterized in this study, and assessed as substrata for the growth of retinal photoreceptor cells. The antioxidant effect putatively inducible by sericin was also evaluated. The blend membranes were found to be mechanically stronger than the fibroin membranes and led to significant enhancement of cell proliferation. Our method also prevented the advanced hydrothermal degradation of fibroin and sericin during processing. The membranes displayed both excellent transparency and suitable water content. However, their permeability was low, and no antioxidative activity related to the presence of sericin was detected when oxidative stress was induced in the cell cultures. The method developed in this study provides silk–based membranes with improved characteristics for tissue engineering applications.