ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Dual-site responsive semi-salamo fluorescence probe with different binding energies for detection of arginine and glutathione

Wenting Guo, Rui Yang, Yunzhao He, Dongzhen Bai, Yan Ma, Tongxin Ji, and Wenkui Dong

School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, China

E-mail: guowenting@mail.lzjtu.cn

Received: 23 June 2025  Accepted: 27 March 2026

Abstract:

Dual-responsive fluorescent probes capable of discriminatively monitoring amino acids and thiols remain challenging yet critical for deciphering pathophysiological processes. We have developed a dual-site responsive monobrominated 2-[O-(1-ethyloxyamide)] oxime-4-bromophenol (BrHS) probe, which demonstrates bidirectional fluorescence responses. Specifically, arginine (Arg) induces a 2.2-fold increase in fluorescence intensity with a detection limit of 246 pM through proton-transfer complexation. In contrast, glutathione (GSH) triggers selective fluorescence quenching with a detection limit of 372 pM via γ-glutamyl-specific hydrogen bonding (O···H–N) and nucleophilic aromatic substitution (SNAr). Real-time cellular imaging conducted in MCF-7 cells enables dynamic monitoring of GSH levels, with observations of dose-dependent fluorescence quenching. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations reveal that glutathione (GSH) exhibits a substantial thermodynamic advantage. Specifically, the Gibbs free energy change (ΔG) of GSH is − 201.75 kJ/mol, indicating it is approximately 14.9 times more reactive than cysteine (Cys). These findings are corroborated by Mayer bond order analysis and electrostatic potential (ESP) charge distribution data. The probe exhibits a wide pH response range and rapid response times (< 10 s for Arg, < 60 s for GSH), enabling effective detection in complex real-world samples. This semi-system, akin to Salamo, presents a novel methodology for dual analyte tracking and detection with atomic-scale specificity, thereby offering transformative potential for the diagnosis of oxidative stress.

Keywords: Semi-salamo fluorescence probe; Arginine; Glutathione; Dual-response

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04853-y

Chemical Papers 80 (7) 7763–7774 (2026)