Interfacial electronic regulation of Ru-functionalized bimetallic MOF/metal oxide nanozyme for multimodal detection of tetracyclines and d-penicillamine.

Tetracycline antibiotics (TCs) and d-penicillamine (D-PA) belong to typical emerging contaminants of Pharmaceuticals and Personal Care Products (PPCPs). This work constructs an interfacial electronically synergized Ru-functionalized Zr/Ce co-modified UiO-66-NH2/Mn-CeO2 heterostructured nanozyme (RZCMC), where interfacial electronic modulation accelerates reciprocal redox cycling of Mn2+/Mn3+ and Ce3+/Ce4+ metal valence pairs to endow RZCMC with prominent peroxidase (POD)-mimicking catalytic activity as well as dual-emission fluorescence for ultrasensitive quantitative detection of PPCPs. RZCMC delivers two distinct fluorescence peaks at 430 nm and 609 nm under 360 nm excitation. RZCMC recognizes TCs through synergistic interactions between exposed Zr/Ce metal nodes, -OC-O- and -NH2, thereby generating marked dual-wavelength fluorescence quenching to support ultrasensitive TC detection with an LOD as low as 0.026 μM. RZCMC displays prominent POD activity via interfacial electronic modulation accelerating reversible metal valence cycling to oxidize TMB into photothermally active oxTMB for constructing a catalytic sensing system. Fukui function analysis identifies the 9S site of D-PA (ƒ- = 0.3262) as the most electron-donating/reactive site to suppress TMB oxidation and the reductive -SH group of D-PA depletes oxTMB, collectively enabling sensitive colorimetric-photothermal dual-mode detection of D-PA with LODs of 7.45 nM and 2.94 nM. A self-developed portable platform with smartphone RGB readout achieves visual PPCPs quantitation for TCs and D-PA. This interfacial electronic regulation composite strategy provides a feasible interfacial-regulation strategy for constructing multimodal nanozyme sensing platforms.