Enhancement of voltammetric properties of silver nanoparticles doped ZnO nanorods for glucose biosensing

In this work, Ag nanoparticles (NPs) doped zinc oxide (ZnO) nanorods (NRs) have been prepared using hydrothermal method to be used as glucose biosensor. The preparation method includes three steps, seed, growth and coating. The first step was to coat the substrate with seed layer in which three samples were prepared using dip coating system with various number of dipping cycles (1, 2 and 3). The second step was to growth ZnO NRs. Finally, Ag NPs were coated on the ZnO NRs. Investigations such as structural properties, surface morphologies, optical properties and electrical resistance were conducted to determine the effects of doping the ZnO NRs with Ag NPs on these properties. As well as, the catalytic properties of glucose oxidase (GOx) and the functionality of the glucose sensor were taking place. The XRD results showed that the prepared samples have good crystallinity and high purity. The FESEM micrographs proved that the samples exhibited nanorods structures with varied thickness which increased by increasing the dipping cycles. The UV-Vis spectroscopy and electrical properties show that the prepared films were transparent with reduced energy gap and surface resistance by increasing the thickness due to the doping with Ag NPs. The results show that the cyclic voltammetry properties were improved by doping the ZnO NRs with 2% of Ag NPs. The scanning rate was 50 mV s(-1) and the voltage range was (- 1.00 to 1.00 V), and the concentration of glucose was from 0 to 500 mu M. The investigations proved that the sensitivity of the sensor was about (350.1 mu A mM(-1) cm(-2)), the detection limit was (38.1 mu M) and the response time was (7 s). As well, a linear increment of current was noticed toward a varied range of glucose concentrations. Thus, the prepared electrode can be used in biosensors and transparent conductive electrodes (TCE) applications.

Automated summary

Ag nanoparticles doped ZnO nanorods were prepared using hydrothermal method for glucose biosensor. The effects of Ag NPs doping on the properties of ZnO NRs were investigated. The catalytic properties of glucose oxidase and the functionality of the glucose sensor were also studied.