2016-12-23T18:49:38

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.

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AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect the SARS coronavirus (SARS-CoV) nucleocapsid protein interaction without fluorescent labeling. The detection limit in our system was approximately 0.003 nM of protein sample. Our result showed that this technique was more competitive than isotopelabeling EMSA. We demonstrated AlGaN/GaN was highly potential in constructing a semiconductor-based-sensor binding assay to extract the dissociation constants of nucleic acid-protein interaction.

As acquired immunodeficiency syndrome (AIDS) caused by HIV-1 (human immunodeficiency virus type 1) has been in the top 10 leading causes of death for recent years, there have been many promising treatment discovered. One of the treatments is by taking non-nucleoside reverse transcriptase inhibitors (NNRTI) to suppress the activity of the HIV-1. The binding affinity of NNRTI to the reverse transcriptase (RT) of HIV-1 is an important factor determining the efficiency of the drug performance. The HIV-1 RT immobilized AlGaN/GaN high electron mobility transistors (HEMTs) were used to find the dissociation constant of NNRTIs. Comparing to conventional drug analyzing, HEMTs assisting experiments are much faster in processing time and lower cost.