Abstract:
Efficient fluorophores with easy synthetic routes and fast responses are of great importance in clinical
diagnostics. Herein, we report a new, rigid pentacyclic pyrylium fluorophore, PS-OMe, synthesised in
a single step by a modified Vilsmeier–Haack reaction. Insights into the reaction mechanism facilitated
a new reaction protocol for the efficient synthesis of PS-OMe which upon demethylation resulted in
a “turn-on” pH sensor, PS-OH. This new fluorescent probe has been successfully used to monitor
intracellular acidification at physiological pH. From the fluorescence image analysis, we were able to
quantify the intracellular dynamic pH change during apoptosis. This new pH probe is a potential
chemical tool for screening, drug discovery and dose determination in cancer therapy.
