Fluorescent AIE dots encapsulated organically modified silica （ORMOSIL） nanoparticles for two-photon cellular imaging

2,3-Bis（4-（phenyl（4-（1,2,2-triphenylvinyl）phenyl）amino）phenyl） fumaronitrile （TPE-TPA-FN or TTF）, which possesses aggregation-induced emission （AIE） characteristic, is doped in organically modified silica （ORMOSIL） nanoparticles. By increasing the weight ratio of TTF to the precursor of silica nanoparticles （the quantities of the precursors were kept the same）, the fluorescence intensity of nanoparticles increased correspondingly, due to the formation of larger AIE dots in the cores of ORMOSIL nanoparticles. The fluorescent and biocompatible nanoprobes were then utilized for in vitro imaging of HeLa cells. Two-photon fluorescence microscopy clearly illustrated that the nanoparticles have the capacity of nucleus permeability, as well as cytoplasm staining towards tumor cells. Our experimental results may offer a promising method for fast and bright fluorescence imaging, as well as bio-molecule/drug delivery to cell nucleus.