Periodic Reporting for period 4 - REM (Resonant Electromagnetic Microscopy: Imaging Cells Electronically)
Berichtszeitraum: 2022-08-01 bis 2024-01-31
For analysing cells and detecting microscale pollutants, electronic sensor technology can potentially offer the required rapid and economic solution. However, existing electronic sensing technologies probe only the geometric properties of such particles, not their material properties. In this project, we worked on to develop electronic sensors that can probe the internal material properties of microparticles and cells. This is accomplished by designing highly sensitive devices in the microwave frequencies which can penetrate into microparticles and probe their properties. By using microwave/electronic sensing at different frequencies, we obtained size, shape and material properties of cells and microparticles. This way we distinguished different classes of microparticles in liquid, or probed the compositional changes inside human cells. The scientific results obtained here can be translated into technological products for environmental and biological applications.
In our efforts, we had to solve several technical problems, such as the uncertainty caused by the vertical position of a cell inside the channel. By using a system of multiple electrodes and particle velocity measurements, we were able to extract the particle's height inside the channel. With this improvement, we were able to distinguish between microplastic and microglass particles in the 20-micron size range. We also showed that our technique can detect the internal compositional changes induced by a chemical used to fix cells.
To make accurate measurements of cells and microparticles, we also developed three-dimensional microscopic structures integrated with our sensors. These structures generate a uniform electric field in the sensing region, so that the vertical position of an analyte particle does not degrade the measurement results. We have built such 3D micro-electrodes based on either liquid or solid sensing structures.
We have also extended microwave measurement technology from single cells to nanoparticles and viruses, by forming sensors around a nanopore. In our search for obtaining sensitive devices, we have also uncovered a novel mechanism for liquid flow rate sensing. This mechanism is based on the periodic pulsations, induced by a constant fluid flow, of a nanoscale membrane integrated with the microfluidic channel. We have also explored how the microwave sensing technology can be used for detecting viruses in air.
Our results were published in many different journal papers, and presented in many conferences. We also received patent protection for the flow-rate sensor technology, and applied for a patent for material-sensing technology developed in this project.