تصنيع المتحسس الحيوي للسكر بإستخدام تركيب اوكسيد الزنك النانوية المطلي بجسيمات الفضه النانوية

Fabrication of Glucose Biosensor Using ZnO Nanostructure Coated By Silver Nanoparticles

Research sciences and medical societies have recently shifted into using cost-effective biosensors to test food & water contaminants, control human biologic processes, assess precise health diagnosis, and more. Researchers and medical practitioners need safe and cheaper means of performing their research, ensuring public safety, and delivering customized health options to patients. One such solution can be easily carried out by using biosensors. The dip coating system was developed to prepare the thin film of ZnO were successfully deposited on indium tin oxide (ITO) substrates. The effects of the dipping cycles were investigated. Dipping processes were applied several times one up to three at concentrations of 0.1 M zinc acetate to obtain homogeneous thin films. In this work, Ag NPs coated ZnO has been prepared using the hydrothermal method to be used as a glucose biosensor. The preparation method includes three steps, seed, growth and coating. The first step was to coat the substrate with a seed layer. The second step was to grow ZnO NRs with concentration 0.050 M of zinc nitrate. Finally, 0.001 M of AgNO3 to obtain Ag NPs were coated on the ZnO nanorods. Investigations structural, compositional, surface morphologies, optical, electrical resistance, and cyclic voltammetry properties were conducted to determine the effects of the preparation condition and coating the ZnO NRs by 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 a good crystallinity and a high purity. Additionally, the structure of ZnO is hexagonal wurtzite. The crystal size was in the nanoscale size with the range of 20-50 nm. As for the examination by FESEM, it was found that homogeneous layers formed when increasing the dipping times of the prepared thin films. The UV-Vis spectroscopy and electrical properties showed 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 coating the ZnO NRs by 0.001 M of Ag NPs for sample S9. 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 – 500 µM. The investigations proved that the sensitivity of the sensor was about 350.1 µAmM-1cm-2, the limit of detection (LOD) was 38.1 µM and the response time was 7 sec. Nevertheless, there is a linear increment of current toward a varied range of glucose concentrations.