The desire for flexible electronics is booming, and development of bioelectronics for health monitoring, internal body procedures, and other biomedical applications is heavily responsible for the growing market. Most current fabrication techniques for flexible bioelectronics, however, do not use materials that optimize both biocompatibility and mechanical properties. This review explores flexible electronic technologies, fabrication methods, and protein materials for biomedical applications. With favorable sustainability and biocompatibility, naturally-derived proteins are an exceptional alternative to synthetic materials currently used. Many proteins can take on various forms, such as fibers, films, and scaffolds. The fabrication of resistors and organic solar cells on silk has already been proven, and optoelectronics made of collagen and keratin have also been explored. The flexibility and biocompatibility of these materials along with their proven performance in electronics make them ideal materials in the advancement of biomedical devices.

There is a pressing need for long-term, controlled drug release for sustained treatment of chronic or persistent medical conditions and diseases. Guided drug delivery is difficult because therapeutic compounds need to survive numerous transport barriers and binding targets throughout the body. Nanoscale protein-based polymers are increasingly used for drug and vaccine delivery to cross these biological barriers and through blood circulation to their molecular site of action. Protein-based polymers compared to synthetic polymers have the advantages of good biocompatibility, biodegradability, environmental sustainability, cost effectiveness and availability. This review addresses the sources of protein-based polymers, compares the similarity and differences, and highlights characteristic properties and functionality of these protein materials for sustained and controlled drug release. Targeted drug delivery using highly functional multicomponent protein composites to guide active drugs to the site of interest will also be discussed. A systematical elucidation of drug-delivery efficiency in the case of molecular weight, particle size, shape, morphology, and porosity of materials will then be demonstrated to achieve increased drug absorption. Finally, several important biomedical applications of protein-based materials with drug-delivery function—including bone healing, antibiotic release, wound healing, and corneal regeneration, as well as diabetes, neuroinflammation and cancer treatments—are summarized at the end of this review.