Gold nanoclusters stabilized with dopa-containing ligands: Catalyst-indicator integrated probe for tumor cell screening

Elevated hydrogen peroxide (H 2 O 2 ) levels not only inflict cellular damage but also serve as a harbinger for various diseases. Tumor cells, in particular, often exhibit an abundance of H 2 O 2 . Hence, the detection of this pivotal molecule assumes paramount importance in monitoring physiological states and expediting cancer diagnosis. To this end, we have ingeniously devised an enzyme-free and monomeric system for intracellular H 2 O 2 detection. Our astute selection of dopa-containing peptidomimetics, replete with ortho-bisphenol and amino acid moieties, has engendered the synthesis of distinctive fluorescent gold nanoclusters (AuNCs). These nanoclusters not only function as a peroxidase-like catalyst, catalyzing the decomposition of H 2 O 2 into hydroxyl radicals (·OH), but also serve as an indicator, with their fluorescence quenched in response to varying H 2 O 2 concentrations. Experimental results evince that our GDpE-AuNCs exhibit remarkable sensitivity, boasting a detection limit of 0.49 μM and a linear range of 5–1000 μM. Moreover, the amalgamation of catalyst and indicator within a single structure, facilitating efficient cellular uptake, engenders intracellular H 2 O 2 detection and discernment of tumor cells. This pioneering approach bequeaths a valuable assay probe for monitoring physiological states and ushering in early disease diagnosis.