Targeting citrate as novel strategy in diagnosing prostate cancer using Rhodamine extended red emissive fluorophore: Sensing mechanism and prostate tumor diagnosis applications

A straightforward protocol was developed to detect the prostate cancer biomarker citrate, using boronic acid as a new recognition unit for exploring the sequence of a Lewis acid-base reaction, Spiro-lactam ring opening, followed by FRET sensing strategies. The probe was evolved from rhodamine-indole extended phenylboronic acid (RIB), which reacted with citrate to produce enhanced red fluorescence in the mitochondria of cell lines (in vitro), allowing the in vivo tracking of citrate. The emission changes were monitored in terms of the endogenous (in situ) citrate concentrations to distinguish normal to prostate cancer mice and their dissected prostate tissues. The practicability of the RIB probe was assessed using urine samples, and paper-made sensor strips as a biochemical reagent to detect the citrate and help diagnose prostate cancer in the early stages. [Display omitted] •Rhodamine-red emissive probe was developed for tracking prostate cancer biomarker citrate.•Exploring a Lewis acid-base reaction, Spiro-lactam ring opening, and FRET mechanisms.•Mitochondria targeting ability, insitu citrate concentration were monitored in cell lines and mice, respectively.•The practicability was investigated using urine, fabrication of paper sensor strips.