37. Biosensors Based on Field-Effect Transistors

Field-effect transistor (FET)-based biosensors are used to detect charge density change as a result of biomolecular recognition on the gate of the transistor. To realize rapid detection and precise analysis of biomolecules using FET-based biosensors, design, and fabrication of chemical modifications at gate surface are important considerations. In this chapter, we showed fundamental working principles of a FET-based biosensor and described its application to the detection of DNA and electrically neutral biomolecules, and to the analysis of cell functions. Since the detection of electrically neutral molecules is one of challenges in electrical/electrochemical detection methods, we showed two possibilities employed stimuli-responsive polymer gel technique and aptamer-based chemistry for a FET-based biosensor. Furthermore, we indicated cell functional analysis results using ion-sensitive FET for a future alternative method of animal experiment. FET-based biosensors have potential advantages in miniaturization of the sensing device and parallel analysis. These advantages promote future medical care such as early diagnosis, telemedicine, and point-of-care test.