Laser-ablative synthesis and photoheating characterization of TiN NPs for biomedical applications

Titanium nitride (TiN) nanoparticles (NPs) prepared by methods of laser ablation in liquids present a novel object, which promises attractive biomedical applications. Here, we review our recent advances in the elaboration of femtosecond laser ablation technique from a TiN target in liquid medium (here, isopropanol) to maximize the efficiency of TiN NPs synthesis and optimize their characteristics. Our experiments showed that the synthesis productivity is dependent on lateral velocity of laser beam scanning during laser ablation with the achievement of productivity saturation at a certain relatively high velocity. The observed phenomenon was attributed to the interaction of laser pulses with cavitation bubbles generated during the ablation process. In addition, we assessed photo heating properties of the synthesized TiN NPs in the near-IR range. It was found that TiN NPs with sizes in 20-50 nm range have the highest heating rate and can be heated to maximal temperatures. As demonstrated by our recent tests in vitro and in vivo, this size range is optimal for biomedical applications, which promises successful applications of these nanoparticles in phototherapy and imaging modalities.