Label‐Free Impedance Biosensors: Opportunities and Challenges

TLDR

Impedance biosensors offer low‑cost, easily miniaturizable, label‑free point‑of‑care solutions, but face common affinity‑capture challenges and unique impedance‑readout issues, with various mechanisms for impedance change upon target binding discussed. The study critically reviews past label‑free impedance biosensor achievements and outlines future research directions. Detection is achieved by monitoring surface impedance changes when unlabeled DNA or protein targets bind to immobilized probes.

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.