Near-Infrared Remotely Controllable Shape Memory Biodegradable Occluder Based on Poly(l‑lactide-co-ε-caprolactone)/Gold Nanorod Composite

Biodegradable occluders, which can efficiently eliminate the complications caused by permanent foreign implants, are considered to be the next-generation devices for the interventional treatment of congenital heart disease. However, the controllability of the deployment process of degradable occluders remains a challenge. In this work, a near-infrared (NIR) remotely controllable biodegradable occluder is explored by integrating poly(l-lactide-co-ε-caprolactone) (PLCL) with poly(ethylene glycol)-modified gold nanorods (GNR/PEG). The caprolactone structural units can effectively increase the toughness of poly(l-lactide) and reduce the shape-memory transition temperature of the occluder to a more tissue-friendly temperature. Gold nanorods endow the PLCL-GNR/PEG composite with an excellent photothermal effect. The obtained occluder can be easily loaded into a catheter for transport and spatiotemporally expanded under irradiation with near-infrared light to block the defect site. Both in vitro and in vivo biological experiments showed that PLCL-GNR/PEG composites have good biocompatibility, and the PEGylated gold nanorods could improve the hemocompatibility of the composites to a certain extent by enhancing their hydrophilicity. As a thermoplastic shape-memory polymer, PLCL-GNR/PEG can be easily processed into various forms and structures for different patients and lesions. Therefore, PLCL-GNR/PEG has the potential to be considered as a competitive biodegradable material not only for occluders but also for other biodegradable implants.