Highly selective and sensitive optosensing of glutathione based on fluorescence resonance energy transfer of upconversion nanoparticles coated with a Rhodamine B derivative

Abstract

A Glutathione (GSH) optical sensor with high sensitivity and exceptional selectivity was developed using one-step synthesized-upconversion nanoparticles (UCNPs, NaLuF4:Gd3+,Yb3+,Er3+) in conjunction with a Rhodamine B derivative (RBD). RBD was loaded on the surface of the UCNPs though non-covalent bonding to serve as an energy acceptor, while UCNPs served as energy donors. The sensor based on a coupling fluorescence resonance energy transfer (FRET) process at an excitation of 980 nm wavelength from UCNP to RBD with a ring-opening process of RBD after the addition of GSH. The sensing probe exhibits a remarkable limit of detection (LOD = 50 nM) for GSH through the enhancement of the fluorescence intensity of RBD at 592 nm, together with a concomitant reduction in the green band of the UCNPs. In addition, the sensing mechanism, characterization of UCNPs, and the selectivity of the fluorescence sensor toward GSH were discussed. The proposed sensor was evaluated on real human serum and urine samples and demonstrated as a highly selective and sensitive probe for the detection of GSH. Keywords: Upconversion, FRET, Derivative dye, Open-ring, Thiol