A dual-responsive acyl thiourea-based turn-on probe for detection of Hg 2+ and Cu 2+ and antibacterial activity

Acyl thiourea derivative (AcTH) was synthesized and characterized. The fluorescence properties of AcTH were studied systematically in the presence of various metal ions. The free probe exhibited low fluorescence emission at 439 nm; however, a significant fluorescence enhancement was observed upon interacting with Hg2+ or Cu2+ ions, due to the formation of metal complexes. The quantitative study showed a satisfactory linear correlation between fluorescence intensity and concentration of Hg2+ and Cu2+ ions in the range of 0.06-5.2 µg mL–1 and 0.1-6.0 µg mL–1, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for Hg2+ were calculated to be 0.015 µg mL–1 and 0.052 µg mL–1, respectively, and for Cu2+, the LOD and LOQ were calculated to be 0.028 µg mL–1 and 0.094 µg mL–1, respectively. The analytical utility of the proposed probe was verified by evaluating the method using blood serum, urine, and water samples. Excellent percentage recovery values (92.6-105.5%) indicate the accuracy of the method. Additionally, the antibacterial activity of AcTH and its metal complexes was evaluated against selected bacterial strains. The metal complexes exhibited enhanced antibacterial activity compared to the free ligand.