Charge Sensitivity Control of Potentiometric Nanobiosensors

• Applicant: Professorin Dr. Margit Zacharias
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Microsystems
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461003068

The project is focused to get a deeper knowledge on the nanobiosensor charge detection mechanism. It is apparent that the sensor surface plays the key role in the development of potentiometric biosensors. We are aiming at investigating, controlling and understanding the respective sensor surfaces. There is a considerable lack of systematic experimental work that explores the theoretical predictions on the role of the surface parameter α (corresponding to pH value/sensitivity) with respect to biomolecule charge sensitivity. In addition, very basic electrochemical design principles are often ignored in literature. We are planning to develop a new concept of a potentiometric nanobiosensor. While the potentiometric measurements can be routinely performed, complications arise usually due to the ambivalent nature of the potential shift that can be caused also by a multitude of artifacts. Therefore, we will develop a differential sensor setup based on ultra-long nanowires using the same nanowire as sensor and reference element. The two nanowire field-effect transistors (FET) are fabricated using two different surface parameters α and hence two different charge sensitivities. Doing so, most undesired disturbances will systematically cancel out. The validity and feasibility of this new concept should be explored within this project. Further, we aim to gain insight into the operation of potentiometric biosensors in general and how nanowire biosensors are possibly affected. This requires a systematically characterized and well understood insulator/electrolyte interface and finally a careful analysis of the sensor responses from individual nanowire FETs.

• DFG Programme: Research Grants