Investigation of the Effects of Laser Radiation at 1.06 µm on Protein Dispersions with Single-Walled Carbon Nanotubes

In this paper, we investigated the effects of near-infrared (1.06 μm) pulsed laser radiation on aqueous dispersions of bovine serum albumin (BSA) and bovine collagen (BC) with single-walled carbon nanotubes (SWCNTs), which can be used as inks for printing biocompatible three-dimensional cellular and tissue engineered structures. Determination of linear and nonlinear optical characteristics was performed using optical spectroscopy and fixed sample location method. Protein dispersions without carbon nanotubes practically did not exhibit nonlinear properties, while the same dispersions with SWCNTs showed strong absorption of optical radiation with incident beam energy increase. This confirms that the nonlinear absorption coefficient in presence of nanotubes is 2-3 orders greater than without nanotubes depending on the threshold intensity values. This suggests that the laser formation of three-dimensional structures had no optical effect on proteins, and denaturation basically occurred due to the heat transfer from carbon nanotubes, which absorbed most of the laser radiation.