(735bt) Fluorescent Nanothermometry Enhanced Laser Tissue Soldering for Minimally Invasive and Robotic Surgery of Fragile Tissues

Laser tissue soldering represents a promising alternative to sutures and staples: it is a surgical technique that combines laser light with a solder paste, a temperature-activatable adhesive material, usually protein-based, to create strong watertight bonds. Furthermore, this technique is, in principle, readily adaptable for minimally invasive procedures. This offers clear advantages over suturing and stapling, as these are difficult to perform in a minimally invasive setting and, when performed on fragile tissues like blood vessels, nerves, and intestine, are susceptible to inflammation, infection, and dangerous fluid leaks. However, the technique's success hinges crucially on the precise temperature management during the procedure.

In our work, we introduced a new approach based on controlled laser tissue soldering guided by fluorescent nanothermometers able to create seamless water-tight sealing. Nanothermometers have been successfully integrated into proteinaceous solders and offer non-invasive temperature measurements. As a critical step towards more accurate and less invasive soldering, we demonstrated automatic temperature control and smart laser power modulation for high-performance laser tissue soldering, enabled by an intelligent solder paste that contains NIR-fluorescent nanothermometers and nanoabsorbers, such as gold nanorods or titanium nitrate nanoparticles. Moreover, we present integrating computer-vision based solder recognition along with multiple approaches to guide the surgery by measuring the nanothermometry-based temperature distribution during soldering for optimal outcome. Finally, we demonstrated the crucial advantages of minimally invasive soldering in clinically-relevant scenarios.