Sustainable and standardized fabrication, recycling, and sterilization of salt-bed casted silk fibroin sponges

Silk fibroin, as a highly versatile biomaterial, is increasingly applied in research, medicine and other sterile applications. The rising usage calls for a robust, standardized and reproducible silk scaffold production and a higher need for silk resources. In this study we standardized the silk fibroin sponges fabrication, set up a quality control protocol, introduced a recycling method to reduce the resources needed and analyzed a sterilization method for translation into preclinical applications. In overall, the development of a fast and efficient quality control protocol led to a reduction in batch-to-batch variabilities. Recycling of silk remnants led to a significant reduction of required silk cocoons of approximately 40 %, with the silk scaffold offering similar product properties as the non-recycled sponges. With the introduction of the recycling trial, we correspond to the requirements for green biomaterials including waste reduction, life cycle introduction and a reduction of environmental impact. Under sterilization conditions, the silk scaffold demonstrated high stability proving that gamma sterilization can be used for bigger batch applications and medical translation. Our establishment of a recycling possibility can pave the way for broader, standardized and "greener" biomedical applications of silk fibroin.