title: AlGaN/GaN high electron mobility transistors for protein-peptide binding affinity study.
abstract: 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(-11) M and 1.596×10(-9) M, 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 (~10 pM of the short peptide) is very close to the LOD (around 2.7-3.4 pM) 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.
authors.affiliation: Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC.
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Huang
authors.forename: Geng-Yen
authors.initials: GY
authors.lastname: Lee
authors.forename: Jen-Inn
authors.initials: JI
authors.lastname: Chyi
authors.forename: Hui-Teng
authors.initials: HT
authors.lastname: Cheng
authors.forename: Chen-Pin
authors.initials: CP
authors.lastname: Hsu
authors.forename: You-Ren
authors.initials: YR
authors.lastname: Hsu
authors.forename: Chia-Hsien
authors.initials: CH
authors.lastname: Hsu
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Huang
authors.forename: Yuh-Chang
authors.initials: YC
authors.lastname: Sun
authors.forename: Chih-Chen
authors.initials: CC
authors.lastname: Chen
authors.forename: Sheng-Shian
authors.initials: SS
authors.lastname: Li
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Yeh
authors.forename: Da-Jeng
authors.initials: DJ
authors.lastname: Yao
authors.forename: Fan
authors.initials: F
authors.lastname: Ren
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Wang
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D000906:Antibodies / Q000737:chemistry*; D001665:Binding Sites; D015374:Biosensing Techniques / Q000295:instrumentation; D003217:Conductometry / Q000295:instrumentation*; D004579:Electron Transport; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic
chemical_list: D017607:Aluminum Compounds; D000906:Antibodies; D010455:Peptides; C513700:aluminum gallium nitride; D005708:Gallium