Two-photon photoluminescence and bio-imaging application of monodispersed perovskite-in-silica nanocrystals with high biocompatibility

Developing two-photon photoluminescence bio-probes with high-biocompatibility is still a challenge. In this work, single CsPbBr3 perovskite NCs were encapsulated into a silica nanoshell to prevent leakage of Pb2+ ion out of the shell, and their two-and one-photon photoluminescence property, as well as the application potential for bio-imaging, were investigated by detailed optical characterization and two-photon cell imaging experiment. It turns out that the core-shell NCs show good two-photon absorption property under the excitation of an 800 nm femtosecond laser and emit green light peaked at 526 nm. The survival rate of human hepatocellular carcinomas (HepG2) cells maintains 96.21% after incubating with the core-shell NCs (16 mu g/mL) for 24 h without adding protective ligands, demonstrating the excellent biocompatibility of the nanoprobes. Based on the excellent biocompatibility and good two-photon absorption property of the perovskite-in-silica nanoprobes, fluorescence imaging of HepG2 cells was demonstrated under 800 nm femtosecond laser illumination. The cumulative fluo-rescence intensity of the two-photon fluorescence images was five times higher than the control group. This work demonstrates the good two-photon photoluminescence property of well-controlled core-shell perovskite-in-silica NCs and provides a new insight for the promising applications in bio-imaging.

Automated summary

Developing biocompatible two-photon photoluminescence bio-probes is challenging. This study encapsulated single perovskite nanocrystals into silica nanoshells to prevent leakage and investigated their photoluminescence properties and potential for bio-imaging. The core-shell nanocrystals exhibited good two-photon absorption properties and emitted green light. They also demonstrated excellent biocompatibility and higher fluorescence intensity in cell imaging compared to the control group under 800 nm laser illumination.