Title
A cell-surface-specific ratiometric fluorescent probe for extracellular pH sensing with solid-state fluorophore
Author
Yan Yang, Mengchan Xia, Hansen Zhao, Sichun Zhang, Xinrong Zhang
Year
2018
Journal
ACS Sensors
Abstract
Extracellular acidity is correlated with the development of various pathological states and bulk pH measurements couldn’t report surface acidity. In this study, we have developed a ratiometric fluorescent probe that aggregates upon interaction with cells, allowing persistent labelling of cells and in situ measurement of cell surface pH. The ternary nanoplatform is constructed by a convenient noncovalent combination of bovine serum albumin protected gold nanoclusters (BSA-AuNCs), fluorescein isothiocyanate (FITC) labeled cationic peptides (CPs) and FITC-free CPs. The red fluorescent AuNCs serve as reference fluorophore, while FITC labeled peptides act as specific recognition element for H+ and FITC unlabeled peptides are used for delivery. The probe displays a sensitive fluorescence ratiometric response for pH in the range of 5.0-9.5 with calculated pKa of 7.2. Further studies have demonstrated that this nanosensor also has properties of high selectivity, reversibility to pH fluctuations as well as low cytotoxicity. The new surface pH-measurement tool was validated in mapping extracellular pH and monitoring acidification regarding cell metabolism, demonstrating its potential for bioimaging and biosensing.
Instrument
FP-8600
Keywords
Fluorescence, Nanostructures, Sensors, Chemical stability, Materials