Laser-Ablative Engineering of ZrN-Based Nanoparticles for Photothermal Therapy and SERS-Based Biological Imaging
Andrei I. Pastukhov, Victoria O. Shipunova, Julia S. Babkova, Ivan V. Zelepukin, Micah Raab, Rebecca Schmitt, Ahmed Al‐Kattan, Artem Pliss, Andrey N. Kuzmin, Anton A. Popov, S. M. Klimentov, Paras N. Prasad, Sergey M. Deyev, Andrei V. Kabashin
Abstract
Zirconium nitride (ZrN) nanoparticles (NPs) can offer appealing plasmonic properties for biomedical applications, but the synthesis of nontoxic, water-dispersible nanoformulations exhibiting plasmonic features in the biotransparency window presents a great challenge. Here, we report the synthesis, by methods of laser ablation, of small ZrN-based NPs, which are unique in combining photothermal heating and near-field enhancement in the transparency window. Depending on the synthesis environment, the formed ZrN-based NPs exhibit plasmonic absorption bands with maxima around 660–670 and 610–630 nm, which are largely red-shifted compared to what is expected from pure ZrN NPs. The observed shift is explained by the inclusion of zirconium oxide ZrO x (1 < x < 2) into NP composition and NP coating by naturally formed ZrO x . We then explored biophotonic applications of ZrN NPs. While pure NPs demonstrate their nontoxicity in vitro, their conjugation with anti-HER1 affibody Z HER1:1907 and subsequent photothermal heating with NIR-I laser cause 100% cancer cell death. In addition, profiting from the field enhancement, we demonstrate bioimaging functionality using a designed surface-enhanced Raman scattering probe based on an NP-conjugated azobenzene-CN-OH molecule as a Raman reporter. Combining a strong photothermal effect and the imaging option, laser-synthesized ZrN/ZrO x NPs promise a major advancement of theranostic modalities based on plasmonic nanomaterials.