Phototoxicity effects of NIR-irradiated cesium tungsten oxide (Cs0.33WO3) nanoparticles on zebrafish embryos: A direct immersion study

Nanoparticles (NPs) with feature sizes ranging between 1 nm and 100 nm have increasingly gained momentum for their versatile functionality as the pharmaceutical agents in many branches of biomedical research and clinical experiments. However, NPs’ inherent material toxicity and the concomitant adverse effects of their function, such as photo-physical properties, often remain a major concern over the issues of environmental safety and human health, and require a thorough assessment before a wide-spread usage can be complied. This research herein investigates the intrinsic and photothermal toxicity of Cs0.33WO3 NPs solution in zebrafish larvae through a direct immersion method. Experimentally, the survival, hatching and malformation rates of zebrafish embryo/larvae as functions of the NP feature sizes, concentration and duration of photothermal dose were examined and analyzed. This study verified that the Cs0.33WO3 NPs has an intrinsic toxicity on a scale of a fraction of 1 mg/ml, and the phototoxicity effect of the NIR-irradiated NPs, when irradiated for 30 min, can affect the embryogenesis of zebrafish larvae and causes 60% and 50% in the survival and delayed hatching rates, respectively, as well as a severe malformation.