From a physics-tech perspective one of the truly high-impact inventions in the field of bio-physics is the Coulter-counter. To this date it is found in applications worldwide and is being extended to counting sub-micron particles, strands of DNA, and even single molecules. By now the topic forms a research field in its own right and is part of many clinical applications due to its simplicity and high-throughput capabilities. The principle of operation is straightforward: a pore is embedded in a thin membrane, separating two reservoirs filled with electrolyte solution. A voltage across the membrane leads to an ionic current flow through the pore. Depending on the pore diameter this current ranges from nano-, for micron sized pores, to pico-amperes for nanopores. When a particle translocates through the pore the open pore current is altered by the presence of this particle because it partially blocks the ion flow and thus increases the resistivity of the pore. We present an ultrafast single micron to sub-micron particle detection method based on a half-bowtie coplanar waveguide. The method is capable of resolving the translocation of these particles at a bandwidth greater than 30MHz and has the potential to trace charge distribution inside of cells. We compare experimentally the simultaneous use of our radio-frequency technique with conventional DC based resistive pulse recordings and find that our method has a throughput that is enhanced by two orders of magnitude. The technique incorporates a microfluidic circuit and has potential to be employed for screening nano-particles and biopolymers such as DNA at frequencies in excess of 1 GHz.

Ultrafast single micron to sub-micron particle detection method based on a half-bowtie coplanar waveguide

2019 Spring National Meeting

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