Bioelectronics also plays an important role in the detection of biological molecules, i.e. in biosensor technology. Different principles like electrochemical, optical, immunological and combinations are conventionally used for this purpose. The decisive advantage of microelectronics lies in the extreme miniaturization of sensor systems that is becoming possible. This is because in recent years, more and more functionalities have been integrated into microchips - as each of us was able to realize from our increasingly smaller smart phones.
Within the framework of a DFG-funded project, an optical biosensor chip is being developed at the Joint Lab, in which the detection is performed by a microring resonators. An optical wave standing in a round waveguide (microring) is modulated by the concentration of the analyte. In the current project, the diffusion of analyte molecules to the microring is enhanced by the attractive DEP effect, thus achieving the smallest detection limits.
The figure schematically shows the sensor design and a scanning electron microscope image (white bar as scale with 10 µm length). The metallic DEP electrodes are designed in a zigzag shape and the exposed area of the microring runs in a trench [Henriksson et al. 2020].