Activatable fluorescent probe based on aggregation-induced emission for detecting hypoxia-related pathological conditions.

Hypoxia, as a condition in which a region of body has low oxygen tension, is closely related to a variety of pathological conditions, and in many diseases local hypoxia occurs that would further increase the severity of diseases. Hence the extent of hypoxia could reflect the related pathological conditions and diseases, and the detection of hypoxia is of great significance. In hypoxia, the elevated level of nitroreductase (NTR) usually occurs, which could serve as a biomarker for hypoxia and thus the related diseases. Herein, an activatable fluorescent probe TPAQS-NO2 based on aggregation-induced emission (AIE) was designed for hypoxia detection via responding to NTR. The probe consists of an electron acceptor quinolinium and an electron donor triphenylamine group. The activated probe shows a large Stokes shift (186 nm). The probe TPAQS-NO2 was successfully used for detecting the early-stage and the advanced-stage tumors via NTR detection in 4T1 tumor-bearing mouse model. Furthermore, the probe TPAQS-NO2 was applied for detecting NTR in the cerebral ischemia (CIS) mouse model. The probe could offer an effective approach for detecting hypoxia-related pathological conditions.