An iridium nanoparticles dispersed carbon based thick film electrochemical biosensor and its application for a single use, disposable glucose biosensor

An iridium nanoparticles dispersed carbon ink was developed for the thick film screen-printing of electrochemical based biosensors. In order to investigate its feasibility for the fabrication of an electrochemical biosensor, a three-electrode configuration (working: iridium-containing carbon; reference: Ag/AgCl; counter: Au) was used and fabricated by screen-printing technology on an alumina substrate. Subsequently, a model glucose biosensor was constructed by immobilizing glucose oxidase covalently on the surface of the iridium-containing carbon working electrode using glutaraldehyde. The H2O2 released from the enzymatic reaction could be detected by the iridium modified carbon working electrode at a relatively low applied potential with a favorable signal-to-noise ratio, suggesting the potential usage of this iridium modified carbon ink for the fabrication of screen-printed biosensors. For practical applications, a mini (working electrode diameter: ∼1 mm), single use, disposable three-electrode sensor was then manufactured on a polyester substrate in bulk using the developed carbon ink by screen-printing technology. The small sizes of the three electrodes of this mini sensor significantly reduced the sample volume required, a volume as low as 2 μL could be used. In the assessment of the potential applications of this mini sensor, a single use, disposable mini glucose biosensor was constructed by depositing glucose oxidase onto the working electrode of this mini sensor. The fabricated mini glucose biosensors responded well to glucose (a linear calibration from 0 to 15 mM), along with a favorable anti-interference ability even at relatively high interferent concentrations, indicating the applicability of this iridium modified carbon based mini sensor for the advancement of single use, disposable electrochemical biosensors based on H2O2 detection using an oxidase.