Label‐Free Impedance Biosensors: Opportunities and Challenges

Abstract

Impedance biosensors are a class of electrical biosensors that show promise for point‐of‐care and other applications due to low cost, ease of miniaturization, and label‐free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label‐free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label‐free impedance biosensors and identify areas for future research.