Two-photon fluorescent probe for detection of nitroreductase and hypoxia-specific microenvironment of cancer stem cell

The NTR-dependent two-photon probe has potential to detect the CSCs in hypoxic niche due to the overexpression of HIFs, which enhanced the NTR activity in CSCs. The two-photon fluorescent molecular probe with a hypoxic specific response group, which can be reduced by nitroreductase (NTR) under hypoxic conditions and then undergo intra molecular charge transfer and intra molecular lipid exchange to release 2-carboxy-2′-hydroxybiphenyl (BCM), which emits strong fluorescent. The large two-photon absorption cross section extends fluorescent excitation spectra to the NIR region, allowing light penetration for deep-tissue imaging, which will greatly promote the tissue penetration and application in biological systems.250