Photoswitchable, Mechanically Deformable Biopolymers With Fast Self-Healing and Good Biocompatibility for Wound Healing

Smart materials are increasingly used across diverse fields due to their rapid response capabilities. However, achieving fast, noncontact mechanical switching at the macroscopic scale while maintaining a balance between mechanical strength and self-healing properties presents a significant challenge. Addressing this issue requires innovative design strategies, which remain a critical scientific goal. Here, we report a novel polymeric material that exhibits dynamic mechanical switching and efficient self-healing behavior. We synthesized structurally controllable biopolymeric materials (AZ-PCLs) using caprolactone (CL) as the polymerization monomer and small-molecule azobenzene derivatives (AZ) as the initiator via intrinsic ring-opening polymerization. Subsequently, we incorporated the natural drug glycyrrhizic acid (GA) as a hydrogen bond donor, facilitating hydrogen-bonding interactions with AZ-PCL to yield a new elastomeric material (AZ-PCLGA) characterized by photoisomerization and dynamic bond-forming properties. This design enables AZ-PCLGA to exhibit noncontact mechanical switching capability as molecular weight increases. Mechanical strength gradually increases as AZ content decreases, with a maximum mechanical strength of up to 21.10 MPa. Remarkably, this exceptional mechanical switching behavior can be regulated by photoisomerization, accompanied by a reduction in healing time and an increase in healing efficiency as the polymer molecular weight increases, with the shortest repair time being 20 minutes and a healing efficiency of approximately 98.7%. In vitro biocompatibility assessments confirm that AZ-PCLGAs exhibit excellent biosafety, underscoring their potential for the development of advanced smart biomedical materials with noncontact, photoswitchable mechanical properties.