Highly Stable and Biocompatible CsPbBr3 Nanocrystals Synthesized by Different Methods for Bioimaging Applications

The low stability and high toxicity of CsPbBr3 perovskite nanocrystals (PNCs) greatly limit their application in the biological field. Here, six different CsPbBr3 PNCs were prepared by ligand-assisted reprecipitation (LARP) and hot injection using oleic acid (OA), oleamine (OAm), (3-Aminopropyl) triethoxysilane (APTES) modification and SiO2 coating, respectively. Different ligands, shells, and synthesis methods give CsPbBr3 PNCs diverse optical properties, stability, and biocompatibility. Among them, OA-OAm-APTES-CsPbBr3@SiO2 has the highest photoluminescence quantum yield (PLQY) (80.74%) and higher stability (fluorescence intensity remains 70% after 15 days in an atmospheric environment). OA-OAm-APTES-CsPbBr3@SiO2 (30 μg/mL) was cocultured with liver cancer cells for 12 h, and the survival rate was 80%, indicating high biocompatibility. Under the observation of the microplate reader, bright green fluorescence appeared in the cytoplasm, indicating that OA-OAm-APTES-CsPbBr3@SiO2 has great application potential in the field of bioimaging.