科研之友
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摘要
An array of p-n junction heterostructures is fabricated by loading the surface of n-type semiconducting ZnO thin film with p-type CuO microclusters (mu Cs) for realization of uric acid biosensor without any external mediator. Uricase is immobilized onto the prepared CuO/ZnO arrayed heterostructure in order to prepare the sensing electrode. The electrochemical performance of the prepared p-n junction based biosensor is investigated by means of cyclic voltammetry. A stable and well-defined peak corresponding to oxidation of uric acid is observed at a very low potential of 0.03 V in a mediator free solution. The largely decreased sensing potential may be attributed to the substantial enhancement of surface reaction kinetics in the formed p-n junction heterostructure due to built-in electric field which facilitate charge transport. A linear sensing response is observed over a range of 0.05-1.0 mM uric acid concentration with a high sensitivity of 1.74 mA/mM. Moreover, the prepared biosensor has good affinity towards uric acid (Km similar to 0.05 mM) and possesses long shelf life (> 20 weeks). The low operating potential (0.03 V) of CuO/ZnO arrayed p-n heterojunction reduces the energy consumption of developed biosensor and efficiently minimizes interference from common oxidizable interferents, thereby, making the biosensor highly selective. Thus, CuO mu Cs/ZnO thin film based p-n junction heterostructure with internal electric field is a novel matrix for developing low powered biosensors to meet future energy demands.
- 出版日期2017-12
