Effect of Laser-Induced Optical Breakdown on the Structure of Bsa Molecules in Aqueous Solutions: An Optical Study

Abstract

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the same time, the patterns observed for an aqueous solution of BSA irradiated with a laser for different time periods were extremely similar to the classical ones. It was established that after exposure to laser radiation, the optical density of protein solutions increases. At the same time, the intensity of BSA fluorescence due to aromatic amino acid residues decreases insignificantly after exposure to laser radiation. In this case, the position of the excitation and emission maximum does not change, and the shape of the fluorescence spot on 3D maps also does not change significantly. On the Raman spectrum after exposure to laser radiation, a significant decrease in 1570 cm−1 was observed, which indicates the degradation of α-helices and, as a result, partial denaturation of BSA molecules. Partial denaturation did not significantly change the total area of protein molecules, since the refractive index of solutions did not change significantly. However, in BSA solutions, after exposure to laser radiation, the viscosity increased, and the pseudoplasticity of aqueous solutions decreased. In this case, there was no massive damage to the polypeptide chain; on the contrary, when exposed to optical breakdown, intense aggregation was observed, while aggregates with a size of 400 nm or more appeared in the solution. Thus, under the action of optical breakdown induced by laser radiation in a BSA solution, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues are damaged to a lesser extent, and fragmentation of protein molecules is not observed.

Optical Study of Lysozyme Molecules in Aqueous Solutions after Exposure to Laser-Induced Breakdown

“…Probably a small part of the protein has degraded, and a part has changed its native state and aggregated, forming functional dimmers or “native-like aggregates” [ 58 ]. Similar but less pronounced effects were found for BSA in the paper [ 33 ].…”

“…The number of optical breakdowns slightly increases ( Figure 2 a), and the average luminescence intensity ( Figure 2 b) decreases by less than a factor of 2 when the protein concentration changes by five orders of magnitude. Characteristically, in a similar study, the changes in these parameters for the optical breakdown in BSA were twice as large [ 33 ]. Thus, the size of the protein globule affects the number of optical breakdowns.…”

Possible Approaches to Studying the Influence of Magnetic Fields and Mechanical Effects on the Physicochemical Properties of Aqueous IgG Colloids

“…Colloidal protein solutions are characterized by pseudoelasticity, a decrease in dynamic viscosity with increasing shear stress [46]. In our experiments, pseudoelasticity was also observed.…”

Interaction of Nd:YAG Laser Radiation with Bovine Serum Albumin Solution

“…The irradiation of protein solutions was carried out at the facility described in detail in [14]. The samples were irradiated with Nd:YAG laser NL300 (Ekspla, Vilnius, Lithuania) with generation of the second harmonic at a wavelength of λ -532 nm.…”