An ISFET Microarray Sensor System for Detecting the DNA Base Pairing

Advances in field-effect biosensors towards point-of-use

The future of medical diagnostics calls for portable biosensors at the point of care, aiming to improve healthcare by reducing costs, improving access, and increasing quality-what is called the 'triple aim'. Developing point-of-care sensors that provide high sensitivity, detect multiple analytes, and provide real time measurements can expand access to medical diagnostics for all. Field-effect transistor (FET)-based biosensors have several advantages, including ultrahigh sensitivity, label-free and amplification-free detection, reduced cost and complexity, portability, and large-scale multiplexing. They can also be integrated into wearable or implantable devices and provide continuous, real-time monitoring of analytesin vivo, enabling early detection of biomarkers for disease diagnosis and management. This review analyzes advances in the sensitivity, parallelization, and reusability of FET biosensors, benchmarks the limit of detection of the state of the art, and discusses the challenges and opportunities of FET biosensors for future healthcare applications.

Emerging Field-Effect Transistor Biosensors for Life Science Applications

Field-effect transistors (FETs) have gained significant interest and hold great potential as groundbreaking sensing technology in the fields of biosensing and life science research [...].

Dual Ion-Selective Membrane Deposited Ion-Sensitive Field-Effect Transistor Integrating a Whole Blood Processing Microchamber for In Situ Blood Ion Testing

Blood ion testing is one of the methods that is commonly used for monitoring the immune status and providing physiological information for disease diagnosis. However, traditional blood ion sensing methods often require well-trained operators to process the whole blood sample and perform the measurements using bulky instruments, making real-time and continuous blood ion sensing at the bedside difficult. To address the above issues, we proposed a dual ion-selective membrane deposited ion-sensitive field-effect transistor (DISM-ISFET) sensor integrating a microchamber to enable on-chip serum extraction and in situ Na⁺/K⁺ ion sensing. As a proof of concept, we sequentially dispensed NaCl and KCl solutions at various concentrations on the DISM-ISFET to find out the highest ion sensitivity and selectivity. Next, we also confirm the high red blood cell sedimentation and serum purity using a microchamber. Finally, we evaluated the system performance using nine clinical whole blood samples and compared their Na⁺/K⁺ ion-sensing results with a commercial pocket ion meter. To sum up, our results showed that a DISM-ISFET system can successfully extract 200 μL serum from 500 μL whole blood sample and simultaneously achieve Na⁺/K⁺ ion sensing. All the sample processes and measurements can be finished within 10 min in a single chip. We envision this compact and easy-to-use system can be potentially used for various medical environments requiring real-time and continuous blood ion monitoring, such as in a hemodialysis room, operation room, and intensive care unit.

Electronic Sensing Platform (ESP) Based on Open-Gate Junction Field-Effect Transistor (OG-JFET) for Life Science Applications: Design, Modeling and Experimental Results

This paper presents a new field-effect sensor called open-gate junction gate field-effect transistor (OG-JFET) for biosensing applications. The OG-JFET consists of a p-type channel on top of an n-type layer in which the p-type serves as the sensing conductive layer between two ohmic contacted sources and drain electrodes. The structure is novel as it is based on a junction field-effect transistor with a subtle difference in that the top gate (n-type contact) has been removed to open the space for introducing the biomaterial and solution. The channel can be controlled through a back gate, enabling the sensor's operation without a bulky electrode inside the solution. In this research, in order to demonstrate the sensor's functionality for chemical and biosensing, we tested OG-JFET with varying pH solutions, cell adhesion (human oral neutrophils), human exhalation, and DNA molecules. Moreover, the sensor was simulated with COMSOL Multiphysics to gain insight into the sensor operation and its ion-sensitive capability. The complete simulation procedures and the physics of pH modeling is presented here, being numerically solved in COMSOL Multiphysics software. The outcome of the current study puts forward OG-JFET as a new platform for biosensing applications.