A capacitive biosensor based on an interdigitated electrode with nanoislands

• An interdigitated electrode (IDE) with nanoislands was developed for capacitive biosensor.
• The sensitivity of capacitive immunoassay could be enhanced by the IDE with nanoislands.
• A parylene film was coated on the IDE to improve the immobilization efficiency of receptors.
• The parylene film coated electrode was applied to detect hepatitis surface antigen (hHBsAg).

A capacitive biosensor based on an interdigitated electrode (IDE) with nanoislands was developed for label-free detection of antigen-antibody interactions. To enable sensitive capacitive detection of protein adsorption, the nanoislands were fabricated between finger electrodes of the IDE. The effect of the nanoislands on the sensitive capacitive measurement was estimated using horseradish peroxidase (HRP) as a model protein. Additionally, a parylene-A film was coated on the IDE with nanoislands to improve the efficiency of protein immobilization. By using HRP and hepatitis B virus surface antigen (HBsAg) as model analytes, the effect of the parylene-A film on the capacitive detection of protein adsorption was demonstrated.

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