Decorating Metal Oxide Nanostructures with Noble Metal NP for Bio-Sensing Applications

Abstract

Biosensors based on functionalized metal oxide nanostructures, such as zinc oxide (ZnO) and Nickel Oxide (NiO), and have been demonstrated using electrochemical methods. Those nanostructures can be deposited on both rigid and flexible substrates at low temperature using rather simple and low-cost processes. Recently, it was discovered that decorating the metal oxide nanostructures with noble metal nanoparticles opens the doors to fabricating biosensors to detect volatile organic compounds. The aim of this work is to improve the knowledge and understanding of a novel composite material structure where wide bandgap semiconductor metal oxide nanostructures are decorated with gold nanoparticles that their surface can be either decorated by functional biological material or converted to catalytic Pt (or Pd) shell. The metal nanoparticle surface functionalization poses some material-related questions regarding the behavior of that nano-structured material, especially when exposed to biological electrolytes or volatile organic compounds (e.g. Ethylene). This will allow us to develop a novel family of biosensors that enable sensitivity, rapidity, and selectivity for the detection of a wide range of target analytes, from pathogens to volatile organic gases, compared to existing bio-electrochemical sensors. The final goal is a flexible all-in-one , highly sensitive and selective biosensors using relatively simple and low cost materials and processing. The sensors will use recent advances in functionalized Gold NP decorated ZnO and NiO electrodes based sensors. ZnO nanowalls was deposited both on rigid (Silicon/ SiO2) substrate and on flexible (Polyimide) substrates. A Scanning Electron Microscopy study of the nucleation and growth of the ZnO nanowalls, and of the NP decoration was conducted. Different conditions such as growth temperature, concentration and time were used. RBS (Rutherford backscattering spectrometry) was performed on the ZnO nanowalls on Polyimide substrate. After mastering the best methods for ZnO nanowalls growth and decoration with Au NP, decoration with different NP such as Platinum or Palladium will be compared. We believe that decoration of metal oxide nanostructures with noble metal nanoparticles will enhance the electrochemical performance of the sensors, for example - highly sensitive detection of VOCs such as ethylene. This new structure should be further explored to reveal its full potential for flexible bio-sensor applications. Figure 1