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

The low stability and high toxicity of CsPbBr 3 perovskite nanocrystals (PNCs) greatly limit their application in the biological field. Here, six different CsPbBr 3 PNCs were prepared by ligand-assisted reprecipitation (LARP) and hot injection using oleic acid (OA), oleamine (OAm), (3-Aminopropyl) triethoxysilane (APTES) modification and SiO 2 coating, respectively. Different ligands, shells, and synthesis methods give CsPbBr 3 PNCs diverse optical properties, stability, and biocompatibility. Among them, OA-OAm-APTES-CsPbBr 3 @SiO 2 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-CsPbBr 3 @SiO 2 (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-CsPbBr 3 @SiO 2 has great application potential in the field of bioimaging.