Electrochemical Gold Deposition on Conductive Electrode Surfaces Towards Sensing Applications

Abstract

Detecting bacterial toxins is incredibly crucial for environmental monitoring and clinical diagnostics in order to inform the public of potential concerns. Currently, bacterial species have been successfully monitored using techniques such as the Polymerase Chain Reaction (PCR). Although beneficial, the disadvantages of the current methods are related to high-cost, lengthy analysis times, and the need for trained personnel. This limits accessibility in resource-poor communities, thus highlighting the importance of this matter. Electrochemical (EC) sensors provide a low-cost, handheld, and portable device that is capable of sensing target biological and chemical components in a timely fashion. EC sensors can be tailored towards a desired target analyte through the use of different conductive electrode materials, surface modification and characterization techniques. 3-D printing technology was investigated to print low-cost electrode chips while decreasing fabrication time. Two conductive filaments (Multi 3D copper based and Protopasta carbon-based) were investigated where neither of them was initially conductive enough to measure redox activity in an electrolyte solution due to low conductivity. Methods to increase conductivity were explored, including electrochemical gold deposition, and embedding a copper wire to assist with electron transfer. The improved 3-D printed electrode chip was successfully used to detect Cu2+ in aqueous samples, leading to more opportunities in biological and chemical applications. Carbon-based screen-printed electrodes were also investigated as another conductive surface. To enhance the conductivity of these surfaces, electrochemical gold deposition was explored resulting in different gold structures. The surfaces were successfully modified with self- assembled monolayers which demonstrates potential for biological and chemical sensing applications.