Field-Effect Transistor Biosensor Platform Fused with <i>Drosophila</i> Odorant-Binding Proteins for Instant Ethanol Detection
Cheol-Min Lim, Jae Young Kwon, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
Odorant-binding proteins (OBPs) have attracted considerable attention as sensing substrates for the development of olfactory biosensors. The Drosophila LUSH protein is an OBP and is known to bind to various alcohols. Technology that uses the LUSH protein has great potential to provide crucial information through odorant detection. In this work, the LUSH protein was used as a sensing substrate to detect the ethanol concentration. Furthermore, we fused the LUSH protein with a silicon-on-insulator (SOI)-based ion-sensitive field-effect transistor (ISFET) to measure the electrical signals that arise from molecular interactions between the LUSH and ethanol. A dual-gate sensing system for self-amplification of the signal resulting from the molecular interaction between the LUSH and ethanol was then used to achieve a much higher sensitivity than a conventional ISFET. In the end, we successfully detected ethanol at concentrations ranging between 0.001 and 1% using the LUSH OBP-fused ISFET olfactory sensor. The OBP-fused SOI-based olfactory ISFET sensor can lead to the development of handheld sensors for various purposes such as detecting toxic chemicals, narcotics control, testing for food freshness, and noninvasive diagnoses.
Microwave Annealing Effect for Highly Reliable Biosensor: Dual-Gate Ion-Sensitive Field-Effect Transistor Using Amorphous InGaZnO Thin-Film Transistor
Inkyu Lee, Kwan H. Lee, Seok Lee, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
We used a microwave annealing process to fabricate a highly reliable biosensor using amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs), which usually experience threshold voltage instability. Compared with furnace-annealed a-IGZO TFTs, the microwave-annealed devices showed superior threshold voltage stability and performance, including a high field-effect mobility of 9.51 cm(2)/V·s, a low threshold voltage of 0.99 V, a good subthreshold slope of 135 mV/dec, and an outstanding on/off current ratio of 1.18 × 10(8). In conclusion, by using the microwave-annealed a-IGZO TFT as the transducer in an extended-gate ion-sensitive field-effect transistor biosensor, we developed a high-performance biosensor with excellent sensing properties in terms of pH sensitivity, reliability, and chemical stability.
High Performance of Silicon Nanowire-Based Biosensors using a High-<i>k</i> Stacked Sensing Thin Film
Tae-Eon Bae, Hyun‐June Jang, Jong‐Heon Yang, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
High performance silicon nanowire (SiNW) sensors with SiO2/HfO2/Al2O3 (OHA) engineered sensing thin films were fabricated. A lower interface state density, a larger capacitance and a stronger chemical immunity, which are essential for enhancing the performance of devices, were accomplished by stacking thin SiO2, HfO2, and Al2O3 layers, respectively, in sequence on the SiNW channel. Compared with the conventional single SiO2 thin film, the staked OHA thin films demonstrated improved sensing performances; a higher sensitivity, a lower hysteresis voltage, and a smaller drift rate, as well as a higher output current. Therefore, the SiNW sensors with OHA stacked sensing thin films are very promising to biological and chemical sensor applications.
Field-Effect Transistor Biosensor Platform Fused with <i>Drosophila</i> Odorant-Binding Proteins for Instant Ethanol Detection
Cheol-Min Lim, Jae Young Kwon, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
Odorant-binding proteins (OBPs) have attracted considerable attention as sensing substrates for the development of olfactory biosensors. The Drosophila LUSH protein is an OBP and is known to bind to various alcohols. Technology that uses the LUSH protein has great potential to provide crucial information through odorant detection. In this work, the LUSH protein was used as a sensing substrate to detect the ethanol concentration. Furthermore, we fused the LUSH protein with a silicon-on-insulator (SOI)-based ion-sensitive field-effect transistor (ISFET) to measure the electrical signals that arise from molecular interactions between the LUSH and ethanol. A dual-gate sensing system for self-amplification of the signal resulting from the molecular interaction between the LUSH and ethanol was then used to achieve a much higher sensitivity than a conventional ISFET. In the end, we successfully detected ethanol at concentrations ranging between 0.001 and 1% using the LUSH OBP-fused ISFET olfactory sensor. The OBP-fused SOI-based olfactory ISFET sensor can lead to the development of handheld sensors for various purposes such as detecting toxic chemicals, narcotics control, testing for food freshness, and noninvasive diagnoses.
Microwave Annealing Effect for Highly Reliable Biosensor: Dual-Gate Ion-Sensitive Field-Effect Transistor Using Amorphous InGaZnO Thin-Film Transistor
Inkyu Lee, Kwan H. Lee, Seok Lee, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
We used a microwave annealing process to fabricate a highly reliable biosensor using amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs), which usually experience threshold voltage instability. Compared with furnace-annealed a-IGZO TFTs, the microwave-annealed devices showed superior threshold voltage stability and performance, including a high field-effect mobility of 9.51 cm(2)/V·s, a low threshold voltage of 0.99 V, a good subthreshold slope of 135 mV/dec, and an outstanding on/off current ratio of 1.18 × 10(8). In conclusion, by using the microwave-annealed a-IGZO TFT as the transducer in an extended-gate ion-sensitive field-effect transistor biosensor, we developed a high-performance biosensor with excellent sensing properties in terms of pH sensitivity, reliability, and chemical stability.
High Performance of Silicon Nanowire-Based Biosensors using a High-<i>k</i> Stacked Sensing Thin Film
Tae-Eon Bae, Hyun‐June Jang, Jong‐Heon Yang, Won-Ju Cho
IF 8.2
ACS Applied Materials & Interfaces
High performance silicon nanowire (SiNW) sensors with SiO2/HfO2/Al2O3 (OHA) engineered sensing thin films were fabricated. A lower interface state density, a larger capacitance and a stronger chemical immunity, which are essential for enhancing the performance of devices, were accomplished by stacking thin SiO2, HfO2, and Al2O3 layers, respectively, in sequence on the SiNW channel. Compared with the conventional single SiO2 thin film, the staked OHA thin films demonstrated improved sensing performances; a higher sensitivity, a lower hysteresis voltage, and a smaller drift rate, as well as a higher output current. Therefore, the SiNW sensors with OHA stacked sensing thin films are very promising to biological and chemical sensor applications.
Reconfigurable field-effect transistors based on complementary metal-oxide semiconductor-compatible synaptic transistors with hybrid polymer-inspired materials
Dual-Control-Gate Reconfigurable Ion-Sensitive Field-Effect Transistor with Nickel-Silicide Contacts for Adaptive and High-Sensitivity Chemical Sensing Beyond the Nernst Limit
Seung-Jin Lee, Seung-Hyun Lee, Seung-Hwa Choi, Won-Ju Cho
IF 3.7
Chemosensors
In this study, we propose a bidirectional chemical sensor platform based on a reconfigurable ion-sensitive field-effect transistor (R-ISFET) architecture. The device incorporates Ni-silicide Schottky barrier source/drain (S/D) contacts, enabling ambipolar conduction and bidirectional turn-on behavior for both p-type and n-type configurations. Channel polarity is dynamically controlled via the program gate (PG), while the control gate (CG) suppresses leakage current, enhancing operational stability and energy efficiency. A dual-control-gate (DCG) structure enhances capacitive coupling, enabling sensitivity beyond the Nernst limit without external amplification. The extended-gate (EG) architecture physically separates the transistor and sensing regions, improving durability and long-term reliability. Electrical characteristics were evaluated through transfer and output curves, and carrier transport mechanisms were analyzed using band diagrams. Sensor performance—including sensitivity, hysteresis, and drift—was assessed under various pH conditions and external noise up to 5 Vpp (i.e., peak-to-peak voltage). The n-type configuration exhibited high mobility and fast response, while the p-type configuration demonstrated excellent noise immunity and low drift. Both modes showed consistent sensitivity trends, confirming the feasibility of complementary sensing. These results indicate that the proposed R-ISFET sensor enables selective mode switching for high sensitivity and robust operation, offering strong potential for next-generation biosensing and chemical detection.
Emerging Dual-Gate FET Sensor Paradigm for Ultra-Low Concentration Cortisol Detection in Complex Bioenvironments
Seung-Jin Lee, Won-Ju Cho
IF 5.6
Biosensors
Cortisol is a pivotal hormone regulating stress responses and is linked to various health conditions, making precise and continuous monitoring essential. Despite their non-invasive nature, conventional cortisol detection methods often suffer from inadequate sensitivity and reliability at low concentrations, limiting their diagnostic utility. To address these limitations, this study introduces a novel paradigm for high sensitivity cortisol detection using field-effect transistor (FET) sensors with dual-gate (DG) structures. The proposed sensor platform enhances sensitivity through capacitive coupling without requiring external circuits. Cortisol detection performance was evaluated by immobilizing monoclonal antibodies activated via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide onto a SnO<sub>2</sub> thin film-based extended-gate. The results revealed a sensitivity of 14.3 mV/dec in single-gate mode, which significantly increased to 243.8 mV/dec in DG mode, achieving a detection limit of 276 pM. Additionally, the reliability and stability of the sensor were validated by evaluating drift effects, confirming its ability to provide accurate detection even in artificial saliva environments containing interfering substances. In conclusion, the DG-FET-based cortisol detection approach developed in this study significantly outperforms conventional FET-based methods, enabling precise monitoring at ultra-low concentrations. This approach holds significant potential for diverse bioassays requiring high sensitivity and reliability in complex environments.
