AlGaN/GaN HEMT Based Biosensor for Detection of the HER2 Antigen Spiked in Human Serum
Shivanshu Mishra, Pharyanshu Kachhawa, Prasenjit Mondal, Surajit Ghosh, Chaturvedula Tripura, Nidhi Chaturvedi
Abstract
This work reports the development of a gallium nitride-based high electronic mobility transistor (GaN HEMT)-based biosensor to detect human epidermal growth factor receptor-2 (HER2) antigen in spiked human serum. The platform devices have been fabricated with a source to drain distance, gate length, and unit gate width of 25, 3, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100 ~\mu \text{m}$ </tex-math></inline-formula> , respectively. The cysteine methyl ester (CME)-based chemistry has been utilized to immobilize the antiHER2 antibody on the sensing region of the sensor. The formation of the CME layer was confirmed through Raman spectroscopy, which shows a peak around a wavelength of 262 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> . The antibody immobilization on the gold surface has been confirmed through enzyme-linked immunosorbent assay (ELISA). The sensor has been electrically characterized before and after each step of the functionalization process. The sensor shows a significant change in the drain current of 0.95 and 1.7 mA at a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{{\mathrm {ds}}} $ </tex-math></inline-formula> of +5 V for 50- and 200-ng/ml concentration of HER2 in spiked human serum. A minor change in the drain current of the sensor, when tested with a nonspecific antigen, suggested the high specificity of the sensor for HER2. The sensor has been tested for a broad range concentration of HER2 antigen from 0.7 pg/ml to 200 ng/ml.