Oxygen vacancy-enriched ZIF-8-encapsulated Au nanoparticles for boosting electrochemical dopamine sensing

Rapid and sensitive detection of dopamine (DA) remains a great challenge in biosensing and disease diagnosis. In this work, we proposed a locking in situ reduction series strategy for designing an electrochemical DA sensor. First, an oxygen vacancy-enriched zeolite imidazole framework-8 (ZIF-8) was prepared by facile solvothermal methods, and then Au nanoparticles (Au NPs) were encapsulated within the ZIF-8 (Au@ZIF-8) to obtain an efficient electrochemical DA sensor. The typical porous structure of the ZIF-8 could prevent the aggregation and growth of the Au NPs, thereby improving the activity and stability of the sensor. Under optimal test conditions, the Au@ZIF-8 sensor demonstrated remarkable electrochemical performance for DA detection, with high sensitivity (24.28 μA μM^-1 cm^-2) in the linear range of 0.5-150 μM and low detection limit (0.003 μM, S/N = 3). Furthermore, the sensor also exhibited good interference resistance and reproducibility. More importantly, DA from bovine serum samples was successfully detected on the Au@ZIF-8 sensor. This study reveals that oxygen vacancy engineering and Au NPs could tune the electronic structure of the sensor and facilitate the adsorption and electrocatalytic oxidation of DA, showing their great potential in the fabrication of biosensors.