Smart self tightening surgical suture from 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 MJm(-3)) and thermal (286 degrees 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 degrees C +/- 1 degrees 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 alpha release). Thus, the study paves the way to biodegradable HPU nanocomposites as advanced non-contact triggered rapid self-tightening surgical sutures for biomedical applications.