Design and strategies for bile acid mediated therapy and imaging

Bioinspired materials have received substantial attention across biomedical, biological, and drug delivery research because of their high biocompatibility and lower toxicity compared with synthetic materials. Bile acids, well-established biomimetic biomolecules, have been reported with respect to their potential applications as carriers of drugs or imaging contrast agents and, most importantly, as oral absorption enhancers. This review introduced the potential mechanisms involved in the oral absorption of bile acids and their derivatives and further focused on the intelligent applications of bile acids or modified bile acids that respond to biological cues as potential oral absorption enhancers for peptides and macromolecular drugs. Our investigations via the modifications of bile acids with various linkers have demonstrated their effects on the degree of oral absorption. Furthermore, we summarized the reports regarding the development of bile acid formulations for the oral delivery of optical imaging contrast agents for GI tract imaging, as well as anticancer drug delivery. Our opinions regarding the utilization of bile acids for biological and biomedical applications provide clear and concise guidance to investigators with respect to the merits and demerits of bile acid use and the selection of appropriate bile acids based on the requirements for improved biomedical applications.