Recent advances on polydiacetylene-based smart materials for biomedical applications

Polydiacetylene (PDA) is a kind of highly conjugated polymer with unique colorimetric and optical properties. A blue and non-fluorescent PDA can be formed upon 254 nm UV irradiation or γ-ray irradiation via 1,4-polymerization of diacetylene monomers, which will transition to red and fluorescent PDA when exposed to environment stimuli, such as pH, temperature, electric and mechanical stresses, and ligand-receptor interactions. As a result, PDA-based materials are particularly attractive for biosensing applications. In addition, the rigid conjugated backbone of PDA derived from its unique topochemical polymerization method also endows exceptional mechanical strength and stability to PDA-based biomaterials, such as liposomes, micelles, and bioscaffolds. The versatility of PDA-based smart materials enables their application in a wide range of biomedical areas. In this review, we briefly summarized the recent progress of biomedical applications of PDA as smart materials in biosensors, drug delivery and bioimaging, as well as tissue engineering. The challenges and outlooks of PDA-based smart materials were also discussed. This review summarized most recent advances of designing strategies of polydiacetylene-based smart biomaterials with unique colorimetric and mechanical properties, as well as their applications in biosensing, drug delivery, and tissue engineering.