Selective detection of Co2+ by fluorescent nano probe: Diagnostic approach for analysis of environmental samples and biological activities

Abstract

Nowadays scientist over the world are engaging to put forth improved methods to detect metal ion in an aqueous medium based on fluorescence studies. A simple, selective and sensitive method was proposed for detection of Co²⁺ ion using fluorescent organic nanoparticles. We synthesized a fluorescent small molecule viz. 4,4'-{benzene-1,4-diylbis-[(Z)methylylidenenitrilo]}dibenzoic acid (BMBA) to explore its suitability as sensor for Co²⁺ ion and biocompatibility in form of nanoparticles. Fluorescence nanoparticles (BMBANPs) prepared by simple reprecipitation method. Aggregation induced enhanced emission of BMBANPs exhibits the narrower particle size of 68nm and sphere shape morphology. The selective fluorescence quenching was observed by addition of Co²⁺ and does not affected by presence of other coexisting ion solutions. The photo-physical properties, viz. UV-absorption, fluorescence emission, and lifetime measurements are in support of ligand-metal interaction followed by static fluorescence quenching phenomenon in emission of BMBANPs. Finally, we develop a simple analytical method for selective and sensitive determination of Co²⁺ ion in environmental samples. The cell culture E. coli, Bacillus sps., and M. tuberculosis H₃₇RV strain in the vicinity of BMBANPs indicates virtuous anti-bacterial and anti-tuberculosis activity which is of additional novel application shown by prepared nanoparticles.

Keywords: Biological activities; Cobalt sensing; Fluorescence organic nanoparticles (FONs); Fluorescence quenching; Ligand-metal interaction.