(261c) Photoresponsive Nanomaterials in Tissue Repair and Radiotherapy

Electromagnetic radiation has a strong history of diverse applications in biotechnology and medicine. Plasmonic nanoparticles (e.g. gold or silver nanoparticles) can efficiently absorb and scatter incident radiation, which can engender transformative advances in biological imaging, diagnostics, and therapeutics. In this presentation, I will discuss our work on interfacing plasmonic nanoparticles with non-ionizing as well as ionizing radiation for applications in tissue repair and cancer radiotherapy. Plasmonic nanoparticles were incorporated within polypeptide matrices leading to the formation of laser-activated tissue-integrating sealant (LATIS) materials. Irradiation of these materials with non-ionizing, near infra-red light facilitated a photothermal response, which, in turn, resulted in rapid, fluid-tight sealing and repair of soft tissues both ex vivo and in live animals. Incorporation of plasmonic nanoparticles within polypeptide fibers led to the formation of laser-activated sutures which combine the benefits of conventional clinical practice (suturing) with photothermal sealing in a single device leading to much improved tissue repair in animals compared to that found with commercial sutures. Delivery of bioactive compounds along with laser sealing resulted in the acceleration of wound healing in mice. As a second application, I will describe our work radiation-induced formation of gold nanoparticles within gels as novel dosimeters for clinical radiotherapy. Irradiation of gold salt-loaded gels with electrons, photons (X-rays) or particles (protons) resulted in formation of gold nanoparticles, which was accompanied by a visible color change in the biomaterial. The intensity of the color change, induced by gold nanoparticle formation, was a function of the dose delivered. The gels were employed to determine and quantify complex dose profiles in 2D and 3D, which facilitates dose determination and planning in tissues and tissue models. The efficacy of the gel radiation dosimeter was evaluated using clinical anthropomorphic phantoms and in canine patients undergoing radiotherapy. Our studies demonstrate that plasmonic nanomaterials, in concert with ionizing and non-ionizing light, can facilitate novel advances in tissue sealing, wound repair, and clinical radiotherapy.