In vivo toxicity evaluation of highly stable perovskite nanocrystals encapsulated in multi-shell polymer

Lead-halide perovskite nanocrystals (PNCs) have recently emerged as promising nano-contrast agent in biomedical imaging due to their outstanding optical properties, e.g. near-unity fluorescence quantum yield, exceptional scintillation property, and large non-linear absorption cross-section. These properties make them ideal for high-resolution deep-tissue imaging, essential for understanding pathophysiological processes in vivo. However, their instability in moisture and presence of lead possesses a significant challenge for their widespread adoption. This has prompted the development of different coating strategies to enhance the stability of nanoparticles in aqueous environment. Here, we used two different biocompatible coating, silica and polystyrene, which stabilized the PNCs in aqueous environment for >2 years and for the first time test their toxicity in vivo. When administered intravenously in mice, these water-stable PNCs did not induce any toxic effects, which was observed for a period of two weeks. This approach will facilitate widespread utilization of PNCs for numerous preclinical studies.