(359c) Graduate Student Award Session: Laser-Activated Biomaterials for Rapid Tissue Repair and Combating Surgical Site Infections

Sutures, staples and tissue glues remain the primary means of tissue approximation in surgery and trauma management. Despite widespread use, conventional sutures do not immediately seal approximated tissue, and are susceptible to bacterial leakage, wound dehiscence and infection. Laser-activated tissue sealing is an alternative approach in which, light-absorbing chromophores and nanoparticles, embedded in sealant biomaterials convert near infrared (NIR) laser light to heat, resulting in photothermal activity. The concomitant rise in local temperature induces structural changes in tissue proteins and the biosealant molecules, which facilitates rapid tissue-biomaterial interdigitation and subsequently, tissue sealing. We developed laser-activated nanosealant (LANS) films consists of NIR-absorbing gold nanorods (GNRs) or indocyanine green (ICG) dye, embedded within a biopolymer matrix (collagen, silk or elastin-like polypeptides). Laser activation resulted in rapid sealing and enhanced the recovery of skin tensile strength in an immunocompetent mouse model of cutaneous skin wound closure, and demonstrated significantly higher efficacies for tissue repair than sutures or cyanoacrylate skin glue. In addition, incisions closed with vancomycin-loaded LANS films demonstrated significantly reduced MRSA counts at the surgical site compared to antibacterial sutures, indicating multifunctional sealing and antibacterial activities of these films. Extending this approach further, we fabricated laser-activated tissue-integrating sutures (LATIS) in order to synergize the benefits of suturing with laser sealing . Laser irradiation resulted in greater recovery of skin biomechanical properties following LATIS approximation of full thickness incisions in live mice compared to commercial sutures. Localized delivery of enhancers of tissue repair, including copper ions or histamine through our nanosealants and sutures further improved skin biomechanical recovery following laser sealing and approximation. Biochemical analyses using histology and immunohistochemistry demonstrated increased angiogenesis, reduced dermal gap, wound contraction and healing compared to conventional sutures or skin glues. Our results indicate that laser sealing and approximation, in concert with molecular enhancers of tissue repair, lead to improved healing outcomes, which can have significant clinical impact on routine surgeries, acute wounds and trauma management.