An electronic enzyme-linked immunosorbent assay platform for protein analysis based on magnetic beads and AlGaN/GaN high electron mobility transistors.

AlGaN/GaN high electron mobility transistor (HEMT) biosensors have attracted attention due to their high sensitivity, stability, and fast response characteristics. Some related studies have been explored but a Debye screening problem exists in physiological solutions hindering the detection of bio-macromolecules. Herein, a novel fast analytical platform for electronic enzyme-linked immunosorbent assay (e-ELISA) is proposed based on AlGaN/GaN HEMT with magnetic beads (MBs); MB-based e-ELISA decouples the modified area from the sensing surface to simplify the assay. Combining the advantages of e-ELISA and MBs, the resulting analytical platform presents a sensing capability beyond the Debye-screening limit and a novel ability to be reused. This platform offers a fast response toward prostate specific antigen (PSA) and the lowest concentration of detection is 1 fg mL. Compared with conventional AlGaN/GaN HEMT biosensors, it shows higher sensitivity (3.73 μA dec) in a linear range (1 fg mL to 1 pg mL), which is within the constraints of emergency care applications. The platform's high sensitivity and fast repeatability endow it with great potential for early and rapid diagnosis.