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    Nano and Micro Technologies

    (F-234) Light-activated sealants for tissue sealing and wound healing applications

    Thursday, October 12, 2023
    2:00 PM – 3:00 PM PDT
    Location: Exhibit Hall - Row F - Poster # 234
    Introduction:: Effective tissue repair with conventional methods of wound closure like sutures and tissue adhesives is limited by concerns related to inflammation, wound dehiscence, and leakage depending on the site of injury. Dehiscence of wounds in the skin or nerves or at the anastomotic site in intestines can lead to infection, morbidity, or mortality. To address these clinical needs, we have developed novel biomaterial-based sealants that are activated by near infrared (NIR) light. These light-activated sealants (LASEs) consist of NIR-absorbing chromophores including indocyanine green, gold nanobipyramids, copper salts, and silver nanoparticles embedded within a biological matrix consisting of silk, chitosan, or their derivatives. Absorption of laser energy by embedded chromophores results in a rise in temperature at the location. This, in turn, facilitates structural changes in the biopolymer and tissue proteins, subsequently leading to their interdigitation and a rapid tissue-biomaterial seal.

    Materials and Methods:: In this study, we evaluated the efficacy of this LASE approach for tissue sealing in repair of skin, nerves, and intestinal tissue in healthy, immunodeficient and / or diabetic and obese mice. We incorporated ICG, AgNPr or CuCl2 to function as photothermal agents into the LASE films (silk or chitosan based). The photothermal agents absorbed near-infrared light from a laser and converted it to heat. This led to the LASE adhering to tissues better and efficiently closing the wounds as compared to the traditional sutures. The efficacy of LASE approach was also evaluated for combating surgical site infections and local delivery of bioactives was also investigated. LASE films were also loaded with an antibiotic – vancomycin - to help combat surgical site infections in the skin. Delivery of histamine receptor agonists provided further enhancement of tissue repair efficacy as determined by biomechanical recovery using Ultimate Tensile Strength (UTS) and barrier function recovery using transepidermal water loss (TEWL), of the healed skin; a significant benefit over sutures was found. Ex vivo tests were conducted in comparison to a commercial tissue adhesive (Tachosil) to test the performance of LASE in intestinal tissues and in vivo experiments were performed with sutures alone as a control. Similarly, for nerves, the sealing efficacy was tested in comparison to sutures alone in vivo.

    Results, Conclusions, and Discussions::

    Skin, intestine and nerve incisions were sealed successfully with the help of LASE films in vivo. Skin incisions treated with LASE were able to keep the incisions closed till day 7. Incisions treated with LASE displayed higher mechanical strength restoration and barrier function. Vancomycin-loaded ICG-LASE exhibited anti-MRSA activity and performed better than commercial anti-bacterial sutures. When employed in the intestines, LASE demonstrated better wound closure strength than Tachosil closed intestine. The results also show improved leak pressure values compared to sutures under ex vivo conditions.


    Our results indicate that the LASE sealing approach can be used as an alternative to or in concert with conventional wound approximation devices such as sutures and staples. To enhance the adhesion potential of LASE to tissues, further modifications can be made. The generated LASEs can be used as a tissue sealant alone or in conjunction with suture/ staples as secondary reinforcement. These LASE films can also be loaded with bioactives to elicit desired immune phenotype.



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