Broadband Electromagnetic Characterization of Individual Biological Cells and Subcelluar Structures
Compared to conventional optical or biochemical characterization of biological cells, broadband electromagnetic characterization can be fast, compact and label free. Additionally, the frequency of the electromagnetic waves can be varied over many decades to detect different subcellular structures that respond at difference length and time scales. For example, using transmission lines fabricated by thin-film technology with feature size on the order of 10 micrometers, we have successfully trapped individual cells at ~10 MHz, porated them at ~100 kHz, and characterized resulted changes in cytoplasm resistance at ~100 MHz and cytoplasm capacitance at ~1 GHz. However, to extend electromagnetic characterization of biological cells to nanometer scale and terahertz frequency, it will be necessary to use state-of-the-art silicon CMOS technology to fabricate test structures with submicron feature size, as well as on-chip generator/detector for near-field terahertz characterization. This is mainly because biological cells must be kept alive in an aqueous solution, but terahertz waves tend to be absorbed and scattered by the aqueous solution. For the ultimate spatial resolution, we have been developing a broadband near-field scanning microwave microscope for the characterization of biological cells and subcelluar structures. This talk will review recent progress as well as future challenges.