Amino nitrogen quantum dots hybrid platinum as efficient peroxidase mimics for fluorescent sensing in microchip

Abstract

Nanocomposites-based nanozyme have been proposed to realize the combination of the respective properties of each component or to achieve cooperatively enhanced catalytic performances, but the systematic catalytic mechanism remains unclear in majority cases. Herein, an entirely new nanocomposite, amino nitrogen quantum dots hybrid platinum (aNDs/Pt hybrid) nanozyme was fabricated to reach a remarkable peroxidase-like activity owing to the synergetic effects between the two components. The roles of the oxygenous groups on the surface of aNDs/Pt hybrid determining their peroxidase-like catalytic activity were evaluated by regulating the functional groups during the synthesis of nitrogen quantum dots. Accordingly, empirical and theoretical evidences were given to identify the catalytic, substrate-binding, and inhibition sites in peroxidase-mimicking catalytic reactions of the aNDs/Pt hybrid. Meanwhile, the catalytic activity of aNDs/Pt hybrid nanozyme shows a strong dependence on the concentration of H₂O₂, based on which a highly sensitive fluorescent sensor for glucose detection in a microchip was established by employing aNDs/Pt hybrid as robust peroxidase. It is found that the developed sensor had excellent glucose sensing capability, including two-section broad linear detection ranges (0.1–6.0 μmol/L and 6.0–1000.0 μmol/L), less sample consumption (2.0 μL) and a low detection limit (31.7 nmol/L). Human serum and saliva samples were successfully examined by the as-proposed sensor with satisfactory results, showing the practical applications. This work not only gives a much deeper understanding on cooperatively catalytic mechanism for nanohybrids-based nanozymes, but also facilitate the design and fabrication of other types of target-specific artificial enzymes.