Stable Electrochemical Measurements of Platinum Screen-Printed Electrodes Modified with Vertical ZnO Nanorods for Bacterial Detection

Thi Hong Phuoc Nguyen,Quang Khue Vu,Duc Hoa Nguyen,Thi Thanh Le Dang,Quang Huy Tran,Van Hieu Nguyen,Matteo Tonezzer

doi:10.1155/2019/2341268

Abstract

The study is aimed at investigating the stability of electrochemical and biosensing properties of ZnO nanorod-based platinum screen-printed electrodes (SPEs) applied for detection of bacterial pathogens. The platinum SPEs were designed and patterned according to standard photolithography and lift-off process on a silicon wafer. ZnO nanorods (NRs) were grown on the platinum working electrode by the hydrothermal method, whereas Salmonella polyclonal antibodies were selected and immobilized onto ZnO NR surface via a crosslinking process. Morphological and structural characteristics of ZnO NRs were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results showed that the ZnO NRs were grown vertically on platinum electrodes with a diameter around 20-200 nm and a length of 5-7 μm. These modified electrodes were applied for detection of Salmonella enteritidis at a concentration of 103 cfu/mL by electrochemical measurements including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The ZnO NR-modified platinum electrodes could detect Salmonella bacteria well with stable measurements, and the signal to noise ratio was much higher than that of 3 : 1. This study indicated that ZnO NR-modified platinum SPEs could be potential for the development of biochips for electrochemical detection of bacterial pathogens.

Highlights

Electrochemical biosensors have recently attracted much attention because of their potential applications in food safety, environmental pollution monitoring, pharmaceutical chemistry, and clinical diagnostics [1,2,3]
We investigated the stability of the electrochemical signal of the zinc oxide (ZnO) NR-modified Pt screen-printed electrodes (SPEs) before and after antibody immobilization and the detection of Salmonella bacteria
The antibody was dropped onto the functionalized ZnO NR matrix working electrodes and incubated for 60 min at room temperature to maximize the binding of antibody to ZnO NRs (Figure 1(d))

Summary

Introduction

Electrochemical biosensors have recently attracted much attention because of their potential applications in food safety, environmental pollution monitoring, pharmaceutical chemistry, and clinical diagnostics [1,2,3]. The electrochemical biosensors have many advantages such as easy operation, low cost, high sensitivity, a simple instrument, and suitability for portable devices [4] These platforms require a stable surface over time for specific applications; it will help the system to improve the electron transfer between electrolytic solution and electrode and minimize the loss of biological molecules during the electrochemical process. Platinum SPEs are developed for various purposes Thanks to their electronic properties and a narrow area of the working electrode, the Journal of Nanomaterials electron transfer would occur [7]. In the strategy of developing a new type of electrochemical biochips for quick and accurate detection of bacterial pathogens, ZnO NR-modified platinum SPEs have been developed, and Salmonella bacteria is selected for testing the stability of electrochemical and biosensing properties of single-modified electrodes. The success of the study will help fabricate multimodified sensors on a biochip for further direct detection of bacterial pathogens

Experimental

Results and Discussion

Conclusions