Development and Characterization of Electrochemical Biosensors using Cu-Ni and Laser Written Platinum
Open Access
- Author:
- Goodnight, Lindsey
- Graduate Program:
- Electrical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- December 17, 2020
- Committee Members:
- Seyedehaida Ebrahimi, Thesis Advisor/Co-Advisor
Timothy Joseph Kane, Committee Member
Kultegin Aydin, Program Head/Chair - Keywords:
- electrochemical biosensors
non-enzymatic
glucose sensing
hydrogen peroxide sensing - Abstract:
- The ability to perform diagnostic tests quickly in non-laboratory settings using pointof- care (PoC) testing devices is of great interest for personalized health monitoring. Electrochemical sensors, in particular, are of interest for PoC testing devices as they can be portable and have quick response time. Non-enzymatic electrochemical testing using engineered electrodes have attracted increasing attention in the bioisensing community since enzymes can be difficult to replicate. Enzymes can be susceptible to environmental conditions such as temperature, pH, humidity, etc. In this work, we develop and investigate different inorganic materials based on transition metals to be used as disposable electrochemical biosensors for glucose and hydrogen peroxide with the potential for in vitro PoC diagnostic applications. The first material explored is phosphate buffer saline (PBS) treated electrodeposited copper-nickel (Cu-Ni) structures for detection of glucose. The PBS treatment and a two-step annealing process enhance the electrode stability and the sensitivity to glucose in a neutral pH in comparison to the Cu-Ni alone. The sensitivity, selectivity, and lifetime were explored through cyclic voltammetry (CV). The of limit detection of this material was 1 nM in neutral pH in 0.1 M Na2SO4. Material characterizations were done with Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and Energy-dispersive X-ray spectroscopy (EDS). The second material explored is laser-written metals, in particular platinum. By applying a laser onto a solution containing metal ions, the thermal energy from the laser decomposes the liquid and results in deposition of a metal film onto a substrate. The sensitivity for various salt concentrations and the effect of applied frequency were tested using square wave voltammetry (SWV). XPS and SEM were used to characterize the material. The limit of detection was found to be 5 fM in PBS. Both deposition methods, i.e. electrodeposition and laser-writing, are low-cost and scalable and can enable fabricating disposable electrochemical sensors for PoC testing.