Application of albumin protein and indocyanine green chromophore for tissue soldering by using an IR diode laser: ex vivo and in vivo studies.

OBJECTIVE: We sought to examine the impact of different parameters of laser soldering on the thermophysical properties of the skin and to optimize these parameters for sealing a full-thickness incision in the rat skin under closed feedback control under in vivo conditions. BACKGROUND DATA: Laser tissue soldering based on protein as biologic glues and other compounds can provide greater bond strength and less collateral damage. Endogenous and exogenous materials such as indocyanine green (ICG) are often added to solders to enhance light absorption. METHODS: In ex vivo study, the temperature increase, number of scan (Ns), and scan velocity (Vs) were investigated. In ex vivo studies, four skin incisions were made over rat dorsa and were closed by using two different methods: (a) wound closure by suture and (b) closure by using an automated temperature-controlled system. An automated soldering system was developed based on a diode laser, IR detector, photodiode, digital thermocouple, and camera. The true temperature of heated tissue was determined by using a calibration software method. RESULTS: The results showed that at each laser irradiance (I), the tensile strength (σ) of incisions repaired in the static mode is higher than in the dynamic mode. It must also be noted that the tensile strength of the repaired skin wound was increased by increasing the irradiance in both static and dynamic modes. However, in parallel, an increase in the corresponding temperature was observed. The tensile strength was measured for sutured and laser-soldered tissue after 2 to 10 postoperative days. Histopathologic studies showed a better healing and less inflammatory reactions than with those caused by standard sutures after day 7. CONCLUSIONS: It is demonstrated that automated laser soldering technique can be practical provided the optothermal properties of tissue is carefully optimized.

Characterization of skin tissue soldering using diode laser and indocyanine green: in vitro studies.

Laser tissue soldering based on protein as biological glues and other compounds can provide greater bond strength and less collateral damage. Endogenous and exogenous materials such as indocyanine green (ICG) are often added to solders to enhance light absorption. The purpose of this in vitro study was to examine the impact of different parameters of laser soldering on the thermo-physical properties of the skin. A mixture of albumin solder and ICG was prepared, and then the coated samples were irradiated by an 810 nm diode laser under different conditions. The temperature rise, number of scans (N(s)), and scan velocity (V(s)) were investigated in this study. The results showed that, at each laser irradiance (I), the tensile strength (sigma) of incisions repaired in static mode was higher than in dynamic mode and that the sigma increased with both increasing N(s) and increasing I. It is therefore important to consider the trade off between scan velocity and surface temperature for achieving an optimum operating condition.

Photopolymerization of dental resin as restorative material using an argon laser.

The effect of the 488-nm wavelength of argon laser at different power densities and irradiation times on the degree of conversion (DC), temperature rise, water sorption, solubility, flexural strength, flexural modulus, and microhardness of bisphenole A glycol dimethacrylate and triethylen glycol dimethacrylate with a mass ratio of 75:25 was studied. Camphorquinone and N,N'-dimethyl aminoethyl methacrylate were added to the monomer as a photo initiator system. The DC% of the resin was measured using Fourier transform infrared spectroscopy. The maximum DC% (50%), which was reached in 20 s, and temperature rise because of the reaction (13.5 degrees C) were both higher at 1075 than 700 mW/cm(2). Water sorption and solubility were measured according to ISO4049, which in our case were 23.7 and 2.20 microg/mm(3) at 1075 mW/cm(2), respectively. A flexural modulus of 1.1 GPa and microhardness of 19.6 kg/mm(2) were achieved above the power density. No significant difference was observed (i.e., p>0.05) for water sorption and flexural strength at 700 and 1075 mW/cm(2).