Green-Emitting Organic Nanoparticles with Aggregation-Induced Emission and Two-Photon Excitation for Fluorescence Imaging of Living Cells/Tissues

Aggregation-induced emission (AIE) nanoparticles (NPs) have been applied in bioimaging for cancer diagnosis due to high fluorescent efficiency. However, the poor cell-permeability as well as autofluorescence of biological cells/tissues caused by UV irradiation is still the key problem of AIE luminophores for biological imaging. Here, we report green-emitting organic AIE luminophores for fluorescence imaging of living cells/tissues, which possess high fluorescence quantum yields and strong AIE under two-photon excitation with near-infrared light beyond 800 nm. These AIE luminophores can bind with Bovine Serum Albumin (BSA) to form biocompatible BSA/AIE-NPs due to their terminal aldehyde groups providing specific anchor sites with the receptor groups in BSA. Furthermore, one/two-photon fluorescence bioimaging for Hela cancer cells has been successfully carried out with BSA/AIE-NPs as the fluorescent probe, and BSA/AIE-NPs show excellent stain properties with fast permeability of only 5 minutes, high cell uptakes and strong fluorescence. The results demonstrate great advantages of BSA/AIE-NPs in fast fluorescent biological imaging as well as further cancer diagnosis and therapy.