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.

Pt/GaN Schottky Diodes for Highly Sensitive Hydrogen Sulfide Detection

“…This can be explained that above 1 ppm of hydrogen sulfide, the sensor gradually saturates, due to the limited binding sites on the interface of the Pt/GaN, which is well studied and demonstrated with binding site model previously. 19 …”

Electronic Biosensors Based on III-Nitride Semiconductors

“…The purpose of these plots is to compare a change in analyte concentration relative to a conductance change from an established baseline value. Figure 6b,c shows examples of such plots utilizing an AlGaN/GaN-based biosensor (69). These plots show three distinct regions of device operation.…”

“…Several studies have reported dose response curves to assess the device sensitivity (69)(70)(71)(72). The purpose of these plots is to compare a change in analyte concentration relative to a conductance change from an established baseline value.…”

“…Abbreviations: DI, deionized; FET, field-effect transistor. Panels b and c were reprinted with permission from Huang et al(69).…”

An integrated microfluidic system with field-effect-transistor-based biosensors for automatic highly-sensitive C-reactive protein measurement

“…FET-based biosensors have been widely used for all kinds of biomolecule detection including proteins, enzymes, DNA etc. The materials of the FET devices may include Si [2], carbon nano-tubes [3,4], or GaN [5,6]. Due to the superior sensitivity and the smaller size, the FET-based sensor plays an important role in biosensing applications nowadays.…”