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[17p-P11-33] Micro-gapped Parallel Plate Elactrodes for IgG Impedance Biosensor
Keywords:Biosensor, Electrochemical Impedance Spectroscopy, IgG
Interdigitated micro-electrodes (IDE) have been extensively studied for electrochemical biosensing applications due to their fast response time and increased the signal-to-noise ratio. IDE consist of a series of parallel microband electrodes in which alternating microbands are together, forming a set of interdigitating electrode fingers. Due to short distance between cathodic and anodic electrodes, ionic species can be efficiently cycled resulting in large signal current production.
According to our current density analysis on IDE, however, it was found that the current was highly concentrated in the edge of the electrode. The surface structure of this edge part can be quite rough and disordered because of the patterning processes such as etching and lift-off. Consequently, the highly concentrating current at the electrode edge will make IDE sensor more unstable in its performance.
To overcome this problem, we develop a new electrode structure consisting of parallel plate electrodes with a micrometer scale gap. The electric current density was simulated and found to be distributed homogeneously on the top flat surface where a smooth and well-ordered structure is expected.
Using IDE and parallel plate electrodes (PPE), we prepared human immunoglobulin G (IgG) biosensor based on electrochemical impedance spectroscopy. Protein G’ was employed as IgG receptor which was covalently attached on both IDE and PPE through self-assembled monolayer. The sensor with PPE exhibited much higher reproducibility than that with IDE. The specificity of PPE based sensor was also tested using IgA and BSA.
According to our current density analysis on IDE, however, it was found that the current was highly concentrated in the edge of the electrode. The surface structure of this edge part can be quite rough and disordered because of the patterning processes such as etching and lift-off. Consequently, the highly concentrating current at the electrode edge will make IDE sensor more unstable in its performance.
To overcome this problem, we develop a new electrode structure consisting of parallel plate electrodes with a micrometer scale gap. The electric current density was simulated and found to be distributed homogeneously on the top flat surface where a smooth and well-ordered structure is expected.
Using IDE and parallel plate electrodes (PPE), we prepared human immunoglobulin G (IgG) biosensor based on electrochemical impedance spectroscopy. Protein G’ was employed as IgG receptor which was covalently attached on both IDE and PPE through self-assembled monolayer. The sensor with PPE exhibited much higher reproducibility than that with IDE. The specificity of PPE based sensor was also tested using IgA and BSA.