Persistent luminescence nanoparticles/hierarchical porous ZIF-8 nanohybrids for autoluminescence-free detection of dopamine

Accurate quantitative detection of biomarkers in complex samples is of remarkable significance for clinical diagnosis and follow-up therapy, which remains challenging due to the severe interference from sample matrix. Herein, a background-free sensing platform toward ultrasensitive dopamine (DA) detection is developed based on a multifunctional nanohybrid by integrating ultrasmall Cr3+-doped zinc gallate (ZnGa2O4:Cr3+, ZGC) persistent luminescence nanoparticles (PLNPs) with hierarchical porous zeolite imidazole framework-8 (HZIF-8). The ZGC PLNPs decorated on the surface of HZIF-8 have long-lasting near-infrared emission and act as signal element, whereas the hierarchically porous HZIF-8 scaffold can serve as an analyte concentrator to enrich DA around ZGC PLNPs. Furthermore, the oxidative polymerization of enriched DA is favored in the alkaline microenvironment provided by 2-methylimidazole in HZIF-8, producing polydopamine (PDA) which finally quenches the luminescence of ZGC/HZIF-8 via photoinduced electron transfer (PET) mechanism. Under the optimized conditions, the proposed nanoplatform exhibits excellent sensitivity and selectivity for the determination of DA in the range of 0.0025–75 μM with a limit of detection down to 0.0010 μM. Benefiting from the superior excitation-free persistent luminescence, this platform also shows satisfactory feasibility in quantitative determination of DA in human serum samples. This new strategy can contribute to the development of PLNPs-based biosensors for practical application in clinical analysis. •A background-free sensor for ultrasensitive dopamine (DA) detection is proposed.•Ultrasmall ZnGa2O4:Cr3+ (ZGC) acts as excitation-free persistent luminescence probe.•Hierarchical porous HZIF-8 serves as both ZGC and analyte concentrator.•The sensor enables excellent feasibility for detecting DA in practical samples.