A fast-responsive two-photon fluorescent turn-on probe for nitroreductase and its bioimaging application in living tissues

A new two-photon fluorescent turn-on probe for nitroreductase (CoNO2-HY) was engineered for monitoring nitroreductase in the lsiving cells and tissues. [Display omitted] •The probe CoNO2-HY is a new two-photon fluorescent nitroreductase probe, with fast response, high selectivity and sensitivity for nitroreductase.•The probe CoNO2-HY responds to nitroreductase with an obvious a large turn-on fluorescence signal.•The probe CoNO2-HY is applied for monitoring nitroreductase in the living cells in both the one- and two-photon modes.•The probe CoNO2-HY is successfully employed to detect nitroreductase in the tumor tissues with a penetration depth of 90μm. Hypoxia may improve the biological activity of nitroreductase (NTR). The development of effective methods for monitoring the activity of NTR plays an important role in the early diagnosis of tumors. Toward this goal, we have developed a new two-photon fluorescence NTR probe CoNO2-HY with fast response, high sensitivity and selectivity, and a large turn-on fluorescence signal. The probe CoNO2-HY could monitor endogenous NTR in living HeLa cells. Importantly, the probe CoNO2-HY is successfully applied to detect the endogenous NTR in the tumor tissue of mice with the penetration depth up to 90μm.