A nitroreductase and acidity detecting dual functional ratiometric fluorescent probe for selectively imaging tumor cells.

Nitroreductase and acidity are common features of a tumor, which is associated with serious disease with a high mortality rate. However, solo detection of nitroreductase or acidic environments may cause false-positive results. Thus, it is very meaningful to develop dual functional probes for detecting nitroreductase and acidity, as these could be used for accurate tumor imaging. Here we report on the first dual functional ratiometric fluorescent probe, NAFP, for acidity and nitroreductase detection. This probe enables the measurement of the acidic microenvironment and the concentration of nitroreductase at the same time and the same site. The probe can obviously distinguish acidity, nitroreductase, and nitroreductase in an acidic environment. Furthermore, confocal fluorescence imaging of A549 cells indicates that NAFP can detect acidity and expressed nitroreductase in living cells.

AND logic-like pH- and light-dual controlled drug delivery by surface modified mesoporous silica nanoparticles.

Recently, the controlled drug delivery system has become a potential platform for biomedical application. Herein, we developed a pH and light-dual controlled cargo release system exhibiting AND logic based on MCM-41 mesoporous silica nanoparticles, which was surface modified using ß-cyclodextrin (ß-CD) with imine bond and azobenzene derivative. The complex of ß-CD and azobenzene derivative effectively blocked the cargo delivery in pH=7.0 phosphate buffered saline (PBS) solution without 365nm UV light irradiation. The cargo was fully released when both factors of acidic environment (pH=5.0 PBS) and 365nm UV light irradiation were satisfied, meanwhile only very little cargo was delivered if one factor was satisfied. The result also demonstrates that the opening/closing of the gate and the release of the cargo in small portions can be controlled.