Development of a fluorescent sensor for dual visual detection of Cr³⁺ and H<inf>2</inf>S using a fluorescein framework and bio-imaging applications

Abstract

A novel responsive fluorescent sensor derived from a fluorescein framework has been successfully fabricated for highly selective dual recognition of Cr3+ and H2S in aqueous solution. Bisanthraflu demonstrated excellent selectivity and great sensitivity towards Cr3+ with a non-fluorescent complex of bisanthraflu-Cr3+ formation via a 2:1 binding mode with minimum detectable amount of 1.7 μM. The fluorescent intensity of the bisanthraflu-Cr3+ complex was markedly restored in the presence of H2S via the displacement approach, potentially applicable as a highly responsive probe for H2S detection with a low detectable concentration of 1.95 μM. This dual functional fluorescent sensor with an On-Off-On approach demonstrated potential for detecting H2S in live HeLa cells with not significant cytotoxicity.