Development and characterization of thick-film printed electrochemical biosensors

The goal of this research is to apply thick-film (screen-printing) technology to produce cost-effective electrochemical biosensors. Two biosensors with clinical significance and applications were selected for development, i.e., a glucose biosensor and a cholesterol biosensor. A self-assembly approach was employed to fabricate a thick-film cholesterol biosensor, based on the electrochemical oxidation of the enzymatically produced H2O 2 by a gold working electrode. This cholesterol biosensor responded well to cholesterol, but suffered interferences from both ascorbic acid and uric acid.; In order to overcome this interference, a thick-film model glucose biosensor was first fabricated based on an iridium nanoparticles dispersed carbon. This model glucose biosensor showed excellent performance including a minimized interference by ascorbic acid, owing to the excellent electrocatalytic ability of the iridium nanoparticles dispersed carbon to detect the enzymatically liberated H2O2. Subsequently, a cost-effective, screen-printed mini sensor was fabricated based on the model sensor. This mini sensor exhibited excellent performance in both the electrochemical oxidation and reduction of H2O2, indicating its potential as a platform technology for the construction of biosensors based on H2O2-generating oxidases. The mechanisms for the detection of H2O2 by this iridium nanoparticles dispersed carbon were proposed.; This mini sensor was then applied to construct single-use, disposable glucose and cholesterol biosensors. These mini glucose and cholesterol biosensors showed excellent performance in the detections of glucose and cholesterol, respectively, requiring as little as 2 muL sample solution. Minimum interference by either ascorbic acid or uric acid was exhibited when both mini biosensors were operated in a reduction mode. Validation studies were conducted for these mini biosensors proving their effectiveness in detecting their specific targets in a calf serum.; A screen-printed integrated heater, coupled with the mini sensor, was fabricated to raise the sensing temperature of the mini sensor. The applications of this integrated heater to enhance the detections of H2O 2, glucose, and total cholesterol were carried out. An elevated sensing temperature enhanced significantly the sensitivities for these detections by as much as five times. A validation study proved the effectiveness of the heated mini glucose biosensor in detecting serum glucose.