Interfacing Materials Science and Biology for Drug Carrier Design

Over the last ten years, there has been considerable research interest in the development of polymeric carriers for biomedicine. Such delivery systems have the potential to significantly reduce side effects and increase the bioavailability of poorly soluble therapeutics. The design of carriers has relied on harnessing specific variations in biological conditions, such as pH or redox potential, and more recently, by incorporating specific peptide cleavage sites for enzymatic hydrolysis. Although much progress has been made in this field, the specificity of polymeric carriers is still limited when compared with their biological counterparts. To synthesize the next generation of carriers, it is important to consider the biological rationale for materials design. This requires a detailed understanding of the cellular microenvironments and how these can be harnessed for specific applications. In this review, several important physiological cues in the cellular microenvironments are outlined, with a focus on changes in pH, redox potential, and the types of enzymes present in specific regions. Furthermore, recent studies that use such biologically inspired triggers to design polymeric carriers are highlighted, focusing on applications in the field of therapeutic delivery. Advances in the design of responsive therapeutic carriers for biomedical applications rely on a greater understanding of the biological microenvironments and how such environments can be harnessed to induce carrier responses. This review provides an overview on the relevant biological microenvironments within cells, focusing on pH, redox potential, and enzyme variations – conditions that can aid in the design of intelligent carrier systems. The review also covers recent literature on the design of smart polymeric carriers and future possibilities in advancing such carriers in the biomedical field.