Improved Ex-Vivo Bond Quality Monitoring of Plasmonic Metal Oxide Biomaterials Mediated Laser Tissue Soldering Process Using Fast Noninvasive Optical Tomographic Imaging.

Background and objectives: Laser tissue soldering (LTS) offers an innovative, suture-free approach to wound closure. However, challenges such as limited tensile strength and prolonged soldering time need solutions. This work combines BSA with PEG to enhance mechanical properties and introduces silver and titanium dioxide nanoparticles to accelerate soldering via localized surface plasmon resonance (LSPR). Real-time SS-OCT monitoring ensures precise evaluation of the soldering process, advancing LTS applications for diverse tissue.

Study design/materials and methods: Four solder compositions (C1-C4) are prepared using combinations of BSA, PEG, silver nanoparticles (AgNP) and titanium dioxide nanoparticles (TiNP). Ex-vivo samples of chicken breast, chicken skin, and goat skin were incised in 1 cm incision with 0.45 mm width and soldered using a 980 nm, 5 W laser. Tensile strength was measured using a tensiometer, while cytotoxicity was assessed using HEK293 cells. SS-OCT captured real-time scattering coefficient changes during soldering, providing insight into coagulation dynamics.

Results: Combining bovine serum albumin (BSA) with PEG and nanoparticles (silver and titanium dioxide), tensile strength in ex-vivo tissue samples increased significantly-by 27% in chicken breast (0.4980 to 0.6366 N/cm²), 28% in chicken skin (0.6080 to 0.7840 N/cm²), and 23% in goat skin (0.6220 to 0.7666 N/cm²). Nanoparticle incorporation reduced soldering time by 33%, achieving complete fusion within 3 min using a laser of optical power of 5 W, central wavelength 980 nm and duty cycle of 50%. Real-time monitoring with Swept-Source Optical Coherence Tomography (SS-OCT) quantified the scattering coefficient changes during soldering, validating efficient bonding. Results demonstrate PEG's contribution to tensile strength, nanoparticles' role in reducing soldering time, and SS-OCT's utility for precision monitoring, supporting LTS as a promising wound closure method.

Conclusion: The study validates PEG's biomechanical reinforcement and nanoparticles' role in efficient LTS. The integration of SS-OCT enables precise, real-time assessment, confirming the clinical potential of this enhanced LTS method for rapid and robust tissue closure.