An Implantable Electrochemical Multi-Analyte Sensor Array for Metabolite Monitoring
Open Access
- Author:
- Clark, Becky L
- Graduate Program:
- Chemical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 19, 2007
- Committee Members:
- Michael V Pishko, Committee Chair/Co-Chair
Craig A Grimes, Committee Member
Jong In Hahm, Committee Member
Darrell Velegol, Committee Member - Keywords:
- electrochemical biosensor
glucose
lactate and pyruvate sensor
array - Abstract:
- Currently, continuous monitoring of metabolites is under development to aid in the detection and management of diseases, such as diabetes, ischemia and sepsis. The methods in practice involve obtaining blood samples to monitor metabolites, which does not lend to patient compliance or the patient’s desire for frequent testing. In order to raise compliance with diabetic testing and aid in early detection of ischemia and sepsis an implantable electrochemical sensor array has been developed to monitor glucose, lactate and pyruvate. The glucose sensors were first fabricated on gold electrode arrays on flexible polyimide sheets by photo-polymerization of the biocompatible polymer poly(ethylene glycol) diacrylate (PEG-DA) to develop hydrogels and encapsulate the sensing elements. Using conventional silicon fabrication methods, arrays of five gold microdisk electrodes were fabricated using lift-off photolithography and sputtering techniques. A redox polymer was then electrostatically attached to the electrode and glucose oxidase (GOX) was entrapped inside the hydrogel on the array of electrodes by UV-initiated photo-polymerization of PEG-DA. The glucose sensor components were then characterized electrochemically with cyclic voltammetry (CV) and square wave voltammetry (SWV) and optimized with CV, SWV and amperometry to improve the sensor’s performance over previous sensors. The developed glucose sensors were also tested in vivo to determine their ability to function in the harsh in vivo environment. The platform developed for the glucose sensor, with its ease of fabrication for multi-analyte sensors, was then implemented with the metabolites lactate and pyruvate. All three sensors responded linearly to the desired analytes with linear ranges that spanned the biologically relevant concentrations.