Design and Demonstration of Tunable Amplified Sensitivity of AlGaN/GaN High Electron Mobility Transistor (HEMT)-Based Biosensors in Human Serum

Abstract

We have developed a swift and simplistic protein immunoassay using aptamer functionalized AlGaN/GaN high electron mobility transistors (HEMTs). The unique design of the sensor facilitates protein detection in a physiological salt environment overcoming charge screening effects, without requiring sample preprocessing. This study reports a tunable and amplified sensitivity of solution-gated electric double layer (EDL) HEMT-based biosensors, which demonstrates significantly enhanced sensitivity by designing a smaller gap between the gate electrode and the detection, and by operating at higher gate voltage. Sensitivity is calculated by quantifying NT-proBNP, a clinical biomarker of heart failure, in buffer and untreated human serum samples. The biosensor depicts elevated sensitivity and high selectivity. Furthermore, detailed investigation of the amplified sensitivity in an increased ionic strength environment is conducted, and it is revealed that a high sensitivity of 80.54 mV/decade protein concentration can be achieved, which is much higher than that of previously reported FET biosensors. This sensor technology demonstrates immense potential in developing surface affinity sensors for clinical diagnostics.

Dual-Aptamer Modified Graphene Field-Effect Transistor Nanosensor for Label-Free and Specific Detection of Hepatocellular Carcinoma-Derived Microvesicles

“…First, HepG2-MVs (6 × 10 5 particles/mL) were introduced to the device for detection. Subsequently, we incubated the AAP-GFET nanosensor at 40 °C in DI water for 5 min to disrupt the binding between HepG2-MVs and the aptamers as reported previously . Finally, such a dissociation and binding process was repeatedly conducted for 3 cycles to examine the regeneration ability of the device.…”

Rheology of the Electric Double Layer in Electrolyte Solutions

“…When a charged surface is immersed in an electrolyte solution, dissolved ions are assembled on it, and an electric double layer (EDL) is formed at the solid–liquid interface to screen the charge of the surface. − The EDL therefore plays a crucial role in various biological and industrial processes, such as biosensing, − enzymology, − coatings, , and storing energy in batteries. ,− The electrostatic screening mechanism and the resulting properties, such as double layer capacitance and shear viscosity, of the EDL are well understood at low ion concentrations. On the other hand, today’s ever-growing activities in biotechnology and new energy development have led to an increasing need for understanding the EDL behavior in concentrated electrolyte solutions, such as ionic liquids (ILs) .…”

Ten Years Progress of Electrical Detection of Heavy Metal Ions (HMIs) Using Various Field-Effect Transistor (FET) Nanosensors: A Review

“…Unlike conventional FETs in which channel conduction is governed by the majority carrier of holes or electrons (depends on the doping), HEMT’s conducting channel is fueled by two-dimensional electron gas (2DEG) arising from spontaneous piezoelectric polarization at the [0001] axis of the AlGaN/GaN heterostructure. Even though the 2DEG carrier mobility is incomparable to mobility of zero-bandgap graphene [ 178 , 179 ], HEMT has considerable potential as a highly sensitive sensor device with fast response time attributed to its higher 2DEG density and thinner barrier in the AlGaN/GaN layer, enabling direct detection of molecules or charged particles absorbed on top of its sensing area (gate) [ 180 , 181 ].…”