In vitro skin wound soldering using SiO2/Au nanoshells and a diode laser

Background and objective

Gold-coated silica core nanoparticles have an optical response dictated by plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes, allowing nanoshells to be tailored to particular applications. The purpose of this in vitro study was to synthesize and use different concentrations of gold nanoshells as exogenous material for skin tissue soldering and to examine the effect of laser soldering parameters (irradiance, number of scans and scan velocity) on the properties of repaired skin.

Materials and methods

Two protein solder solutions mixed with albumin solder and two different gold nanoshell concentrations (1 and 2 ml) were prepared. A 2-mm-thick, 20-mm-long incision was made on the surface of depilated sheep skin strips using a surgical blade, and after the addition of the solder solution, it was irradiated with a diode laser (810 nm), varying the irradiance I (24–83 W/cm²), the number of laser scans N_s (2–10 scans), and the scan velocity $v_s$ (0.2–0.42 mm/s). The temperature T was monitored using a digital K-type thermometer (CHY502A1, CHY Firemate Co., Taiwan) that was positioned under the skin with a probe diameter of 0.5 mm and a response time of 0.1 s. Approximately 30 min after the completion of the soldering process, the tensile strength σ was evaluated in a tensile test.

Results

The results show that the tensile strength of the repaired skin increased with increasing laser irradiance for both gold nanoshell concentrations. At a constant irradiance, the tensile strength of the repaired incisions increased with increasing N_s and decreasing $v_s$. A higher irradiance resulted in a larger tissue temperature rise.

Conclusion

It was demonstrated that gold nanoshells can be used for laser tissue soldering, provided that the operating conditions are carefully optimized. In our case the optimal parameters were: σ = 0.16 N/mm² at I ∼ 60 W/cm², T ∼ 65 °C, N_s = 10 and $v_s=0.2\text{mm/s}$.