Near infrared light enhanced a green vitamin Cu/Co@MOF laccase-like nanozyme activity for estrogen colorimetric detection.

The development of a bimetallic metal-organic framework (Cu/Co@MOF) is presented using copper and cobalt as central ions and vitamin B6 as the green ligand through a straightforward microwave digestion technique that act as potent laccase mimics, specifically designed for estrogen (including estriol, estradiol, and diethylstilbestrol) sensing. A newly designed Cu/Co@MOF nanozyme probe exhibits significantly improved laccase-mimicking activity and photothermal efficiency when exposed to near-infrared (NIR) light. Experimental investigations elucidated that NIR promoted the activation of molecular oxygen (O2) for generation of producing superoxide radicals (∙O2−) and electron transfer efficiency (Co3+/Co2+-Cu+/Cu2+), improving oxygen activation efficiency and catalytic cycling. Under NIR stimulation, the catalytic efficiency of the Cu/Co@MOF nanozyme increases markedly, achieving a four times improvement compared to non-stimulated conditions. Importantly, Cu/Co@MOF maintains impressive stability across a broad pH range and temperatures. The absorbance of estradiol shows a linear correlation with concentrations spanning from 0.02 to 25 µg/L, 0.012 to 36 µg/L, and 0.045 to 15 µg/L, with corresponding detection limits of 0.016 µg/L, 0.006 µg/L, and 0.038 µg/L, respectively. Furthermore, the colorimetric sensor based on Cu/Co@MOF demonstrates outstanding performance in detecting estrogens.