Beyond the Debye length in high ionic strength solution: direct protein detection with field-effect transistors (FETs) in human serum

• Published in: Scientific reports Vol. 7; no. 1; pp. 5256 - 15
• Main Authors: Chu, Chia-Ho, Sarangadharan, Indu, Regmi, Abiral, Chen, Yen-Wen, Hsu, Chen-Pin, Chang, Wen-Hsin, Lee, Geng-Yen, Chyi, Jen-Inn, Chen, Chih-Chen, Shiesh, Shu-Chu, Lee, Gwo-Bin, Wang, Yu-Lin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.07.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 631/57/2282; 639/638/11/511; 692/700/139/1449; 82/62; 9/10; Aptamers; Biosensors; Humanities and Social Sciences; Ionic strength; Ions; multidisciplinary; Science; Science (multidisciplinary); Sensors; Transistors
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-05426-6

In this study, a new type of field-effect transistor (FET)-based biosensor is demonstrated to be able to overcome the problem of severe charge-screening effect caused by high ionic strength in solution and detect proteins in physiological environment. Antibody or aptamer-immobilized AlGaN/GaN high electron mobility transistors (HEMTs) are used to directly detect proteins, including HIV-1 RT, CEA, NT-proBNP and CRP, in 1X PBS (with 1%BSA) or human sera. The samples do not need any dilution or washing process to reduce the ionic strength. The sensor shows high sensitivity and the detection takes only 5 minutes. The designs of the sensor, the methodology of the measurement, and the working mechanism of the sensor are discussed and investigated. A theoretical model is proposed based on the finding of the experiments. This sensor is promising for point-of-care, home healthcare, and mobile diagnostic device.