Smart self-tightening surgical suture from a tough bio-based hyperbranched polyurethane/reduced carbon dot nanocomposite.

Design and fabrication of a smart bio-based polymeric material with potent biocompatibility and high performance still remain a challenge in the biomedical realm. In this context, a potential smart suture was fabricated from starch modified hyperbranched polyurethane (HPU) nanocomposites with different weight percentages of reduced carbon dots for the first time. The desired mechanical (tensile strength: 32.14 MPa, elongation at break: 1576% and toughness 439.28 MJ m-3) and thermal (286 °C) attributes of the suture were achieved with 2 wt% of reduced carbon dots in an HPU matrix. The non-contact self-tightening behavior was observed just within 15 s at body temperature of 37 °C ± 1 °C with notable shape fixity (99.6%) and shape recovery (99.7%) effects. The nanocomposites displayed in vitro biodegradability and hemocompatibility. Low lactate dehydrogenase activity and minimal red blood cell lysis indicated the anti-thrombogenicity and anti-hemolytic properties of the nanocomposites. The suitability of the fabricated nanocomposites as a smart biomaterial was supported by the inherent biocompatibility as observed by the growth and proliferation of smooth muscle cells and endothelial cells. Furthermore, they exhibited minimal immunogenic response (TNF α release). Thus, the study paves the way to biodegradable HPU nanocomposites as advanced non-contact triggered rapid self-tightening surgical sutures for biomedical applications.