(39f) Coffee-Ring Biomaterials As Nanoglues for Laser-Activated Tissue Sealing

Skin grafts are used to facilitate healing in cases of tissue loss from infections, deep burns, and large, open wounds that are too big to heal on their own. Several surgical techniques including sutures and tissue adhesives are used to restrain the graft onto the wound but can be traumatic, do not provide fluid tight seals, can leave wounds susceptible to infection, and lead to complications after surgery. There is a critical need to develop alternative surgical methods for more reliable skin grafting. Laser-activated tissue sealing provides an effective alternative approach in securing skin grafts to host tissue. In this approach, plasmonic nanoparticles, which convert incident laser light to heat, are embedded within biomaterials leading to the formation of photothermal nanocomposites. Incident near infrared laser light is converted to heat, which facilitates integration of the biomaterial with the tissue leading to efficient sealing. In the present study, we employed the coffee-ring effect to localize gold nanorods at the periphery of sealant biomaterials, including silk, chitosan and alginate, in order to facilitate sealing only at the edges and minimize thermal damage to tissue. The temperature rise following laser irradiation was determined experimentally and studied using mathematical modeling. The efficacy of these coffee-ring biomaterials was determined for sealing ex vivo tissues and in full-thickness wounds in mice skin. Recovery of tissue mechanical properties and histopathological analyses were used to determine the efficacy of sealing using laser activation of coffee-ring biomaterials as well as with conventional methods including suturing. Our studies indicate that coffee-ring biomaterials are promising laser-activated sealants in soft tissue approximation including in skin graft surgeries.