AlGaN/GaN high electron mobility transistors for protein–peptide binding affinity study

• Published in: Biosensors & bioelectronics Vol. 41; pp. 717 - 722
• Main Authors: Huang, Chih-Cheng, Lee, Geng-Yen, Chyi, Jen-Inn, Cheng, Hui-Teng, Hsu, Chen-Pin, Hsu, You-Ren, Hsu, Chia-Hsien, Huang, Yu-Fen, Sun, Yuh-Chang, Chen, Chih-Chen, Li, Sheng-Shian, Andrew Yeh, J., Yao, Da-Jeng, Ren, Fan, Wang, Yu-Lin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2013; Elsevier; Elsevier B.V. Published by Elsevier B.V
• Subjects: Aluminum Compounds - chemistry; Antibodies - chemistry; Binding affinity; Binding Sites; Biological and medical sciences; Biosensing Techniques - instrumentation; Biotechnology; Conductometry - instrumentation; Dissociation constants; Electron Transport; Equipment Design; Equipment Failure Analysis; Fundamental and applied biological sciences. Psychology; Gallium - chemistry; GaN; High electron mobility transistors; Immunoassay - instrumentation; Peptides - chemistry; Protein Binding; Protein Interaction Mapping - instrumentation; Reproducibility of Results; Sensitivity and Specificity; Sensors; Transistors, Electronic; High electron mobility transistors; Binding affinity; Sensors; GaN; Dissociation constants; Detector; Peptides; Mobility; Affinity; Dissociation constant; Transistor; Protein
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2012.09.066

Antibody-immobilized AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect a short peptide consisting of 20 amino acids. One-binding-site model and two-binding-site model were used for the analysis of the electrical signals, revealing the number of binding sites on an antibody and the dissociation constants between the antibody and the short peptide. In the binding-site models, the surface coverage ratio of the short peptide on the sensor surface is relevant to the electrical signals resulted from the peptide–antibody binding on the HEMTs. Two binding sites on an antibody were observed and two dissociation constants, 4.404×10−11M and 1.596×10−9M, were extracted from the binding-site model through the analysis of the surface coverage ratio of the short peptide on the sensor surface. We have also shown that the conventional method to extract the dissociation constant from the linear regression of curve-fitting with Langmuir isotherm equation may lead to an incorrect information if the receptor has more than one binding site for the ligand. The limit of detection (LOD) of the sensor observed in the experimental result (∼10pM of the short peptide) is very close to the LOD (around 2.7–3.4pM) predicted from the value of the smallest dissociation constants. The sensitivity of the sensor is not only dependent on the transistors, but also highly relies on the affinity of the ligand-receptor pair. The results demonstrate that the AlGaN/GaN HEMTs cannot only be used for biosensors, but also for the biological affinity study. ► AlGaN/GaN high electron mobility transistors detected a short peptide. ► Antibody immobilized on transistors bind the peptide to form a complex. ► Binding affinity of the complex was studied using binding-site models. ► Dissociation constants and the number of binding sites were revealed.