Chemical Research in Chinese Universities ›› 2026, Vol. 42 ›› Issue (5): 1572-1576.doi: 10.1007/s40242-026-6083-3

• Research Articles • Previous Articles     Next Articles

A G-Quadruplex Rigidity-induced Quenching-Shielding Strategy for OFF-ON Fluorescent Detection of Strontium Ions

CHEN Linyuan1, CHEN Chen1, ZOU Li2, LING Liansheng1, ZHANG Ji3   

  1. 1. School of Chemistry, Institute of Green Chemistry and Molecular Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China;
    2. School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, P. R. China;
    3. State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510006, P. R. China
  • Received:2026-04-02 Accepted:2026-06-02 Online:2026-10-01 Published:2026-09-24
  • Supported by:
    This work was supported by the Guangdong Province Basic and Applied Basic Research Foundation-Guangdong Province Natural Science Foundation General Project, China (No. 2025A1515012747).

Abstract: Human telomeric DNA sequences (5′-TTAGGGTTAGGGTTAGGG-TTAGGG-3′) can be induced by strontium ions to form G-quadruplex structures. Based on this property, a novel “OFF-ON” fluorescent sensor was developed for Sr2+ using a G-quadruplex/ acridine orange-graphene oxide (G4/AO-GO) system. In the presence of Sr2+, the telomeric DNA folds into a rigid G-quadruplex structure, which not only inhibited the adsorption of acridine orange (AO) on graphene oxide (GO) and recovered the fluorescence of AO, but enhanced the fluorescence of AO as well. Spectroscopic results confirmed the formation of stable G-quadruplexes in the presence of Sr2+. Under the optimum condition, the fluorescence intensity showed a good linear relationship with the Sr2+ concentration over the range from 10 nmol/L to 3.0 μmol/L, and the detection limit was 3.6 nmol/L. The sensor also exhibited high specificity and selectivity, and was successfully applied to the determination of strontium in mineral water samples. This sensing platform provides a promising method for in situ monitoring of Sr2+ in geological surveys, environmental safety assessment, and food quality control.

Key words: G-Quadruplex, Strontium ion, Graphene oxide, Fluorescent sensor