A simple fluorescent probe for monitoring pH in cellsbased on new fluorophorepyrido[1,2-a]benzimidazole

•A new fluorophore pyrido[1,2-a]benzimidazole has been synthesized and characterized.•The probe shows remarkable properties including high quantum yield, low cytotoxicity and good biocompatibility.•The pyrido[1,2-a]benzimidazole-based sensor can be used for detecting and imaging pH in cells.

A simple pH fluorescent probe based on new fluorophorepyrido[1,2-a]benzimidazole derivative has been synthesized and characterized. This probe responds to acidic pH (pKa = 5.18) with high quantum yield (φ = 0.96), fast response (within 1 min), high selectivity and sensitivity. The response mechanism of the fluorescent probes relies on ICT change. The probe was successfully used to monitor intracellular H+ within RAW 264.7 cells.

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