Control of Dimensional and Optical Properties of Laser-Synthesized TiN Nanoparticles for Biomedical Applications

The dimensional and optical properties of nanomaterials largely determine the prospects of their application in biomedicine. We have studied the feasibility of controlling the dimensional and optical characteristics of laser-synthesized titanium nitride (TiN) nanoparticles (NP) using various liquid media (water, isopropanol, acetone, or acetonitrile) and laser focusing parameters and energy. Laser ablation of the TiN target in all solvents resulted in the formation of spherical NPs with the mode and half-width of the size distribution dependent on the type of liquid. We show that the use of organic solvents can produce NPs with higher coefficients of mass extinction (up to 35.2 L cm^–1 g^–1) and of photothermal conversion (up to 69%) in the window of relative biotissue transparency for aqueous medium. It is also demonstrated that the mode and half-width of the TiN NP size distribution decreases as the distance from the lens to the target surface increases or laser radiation energy decreases. These findings form a quantitative basis for developing laser-synthesized TiN NPs with controlled properties and they also prove their high potential for applications in biomedicine.