A novel sensitive NMOF fluorescent probe for two photon imaging of glutathione in chemo-resistant cancer cells

Abstract Nanoscale metal-organic frameworks (NMOFs) with fluorescence properties have been proved to be a kind of excellent single photon fluorescence probes for sensitive detection and imaging of bioactive molecules in recent years. However, this kind of NMOFs fluorescent probe still exists some problems to be solved such as biological autofluorescence interference and poor tissue penetration. Compared with single photon fluorescence probes, two-photon fluorescence probes have attracted more and more attention in biomedical research recently due to the intrinsic advantages originated from simultaneous absorption of two low energy photons, such as lower excitation energy, less photodamage, deeper tissue penetration, smaller interference of spontaneous fluorescence and higher imaging resolution. Here, simply based on host-guest interactions, we for the first time developed a novel sensitive two-photon NMOF fluorescence probe for monitoring the fluctuation of endogenous glutathione (GSH) level in living cells, which plays an important role in cellular redox homeostasis. The detection limit of this sensitive probe is as low as 87 nM. After being successfully devoted to monitor the fluctuation of endogenous glutathione levels in different types of living cell lines, the probe was also successfully employed to evaluate the relationship between chemotherapeutic drug doxorubicin (DOX) resistance and GSH levels in Hela, HepG2 and normal L02 cells.