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This paper reports on the application of dielectrophoresis techniques in the radiofrequency range, in order to probe inner dielectric specificities and therefore characterize individual biological cells. The novelty of this work consists in exploring the capability of UHF signals to generate DEP-driven motion effects on flowing biological cells in a microfluidic micro-device. Additionally, with applied...
This paper introduces the handling of a single cell by dielectrophoresis technics using UHF frequencies (above 100 MHz) inside microfluidic microsystems implemented on Bipolar-Complementary Oxide Semiconductor (BiCMOS) technology. Dielectrophoresis (DEP) is a well-established technique used in the kHz frequency range to manipulate, trap and sort electrically polarized cells by exposing them to a non-uniform...
Previously, the design of our novel low-dispersion phase-shifter unit cell with two asynchronous MEMS switches was limited to 90°, so that four unit cells (90°, 90°, 90° and 45°) with a total of eight MEMS switches were required for a 3-bit phase shifter. This not only increased the size and loss of the phase shifter, but also decreased its yield and reliability. Recently, we hypothesized that by...
Using a coplanar waveguide with a series gap in conjunction with dielectrophoresis trapping, consecutive S-parameter measurements between 0.5 and 20 GHz were quickly performed with and without a Jurkat cell trapped to compensate for a relatively noisy and drifting background. Based on sixteen measurements repeated on eight live cells and eight dead cells, differences in both return and insertion losses...
A novel microfluidic biosensing platform based on Bipolar-Complementary Oxide Semiconductor (BiCMOS) technology is presented. The device relies on a quadruple electrode system and a microfluidic channel that are directly integrated into the back-end-of-line (BEOL) of the BiCMOS stack. For proof of concept repeatable electrical trapping of single SW620 (colon cancer) cells in the quadruple electrode...
This paper reports a low-dispersion metamaterial-based 3-bit phase shifter which occupies an area of approximately 5 mm2 and uses only six microelectromechanical systems (MEMS) switches. The phase shifter is based on a coplanar slow-wave structure with defected ground and comprises three unit cells of 180°, 90° and 45° phase shifts, respectively. Each unit cell uses two single-pole-single-throw MEMS...
Using a coplanar waveguide with a series gap in conjunction with dielectrophoresis trapping, consecutive S-parameter measurements between 0.5 and 20 GHz were quickly performed with and without a Jurkat cell trapped to compensate for a relatively noisy and drifting background. This allowed the small cytoplasm capacitance, on the order of 10 fF, to be reliably extracted. The extracted cytoplasm capacitance...
Based on a homemade probe station on top of an inverted microscope for simultaneous microwave measurement and visual validation, broadband detection of live Jurkat cells was successfully extended from 2–3.5 GHz to 0.5–20 GHz with comparable sensitivity and reproducibility. With a carefully optimized coplanar waveguide, closely spaced microwave probes, and frequent calibrations, reference planes were...
This paper reports compact, wideband, low-dispersion, metamaterial-based phase shifters with lower loss, wider bandwidth, and fewer MEMS switches than previous designs. The present design is based on a novel 90° unit cell which uses two synchronized MEMS switches that are actuated and unactuated in unison for the through and delayed states, respectively. By combining three of these 90° unit cells...
Novel phase shifters were designed by using only two MEMS switches to control a metamaterial-based slow-wave structure in each unit cell. A unit cell with an area smaller than 1 mm2 exhibited a phase shift of 54±15°, an insertion loss of less than 0.9 dB, and a return loss of higher than 15 dB between 12 GHz and 18GHz. Modeling not only agrees with the measured data, but also points out possibilities...
A novel broadband microchamber for electrical detection of live and dead biological cells was designed, fabricated and tested. The microchamber was formed between a gold coplanar waveguide fabricated on a quartz slide and the microfluidic channels fabricated in a polydimethylsiloxane cover. The coplanar waveguide allowed broadband impedance matching and efficient cell trapping. The microfluidic channels...
Intermodulation distortion in MEMS capacitive switches was analyzed both theoretically and experimentally as a function of tone spacing and RF power. The theory and experiment consistently showed that, under high RF power, additional distortion was caused by self-heating of the switch membrane by the RF power, which decreased the membrane spring constant significantly. The results implied that, well...
Recently, the promising effects induced by pulsed electric fields with high intensity and short duration have been highlighted. At the nanosecond time scale, electric pulse targets become both the plasmatic membrane and the sub-cellular structures (possibility of intracellular manipulation). In this paper, a circuit cell model with nucleus is presented, validated and used in order to assess the different...
We report, for the first time, the benefit of RF burn-in at power levels significantly higher than the nominal handling capacity of micro-electromechanical capacitive switches. The benefit appears to be permanent, so that, after burn-in, the switches remain less vulnerable to dielectric charging and, presumably, more reliable. It was speculated that high RF power permanently changed the bond configuration...
A CMOS control circuit capable of closed-loop capacitance sensing and control of RF MEMS switches was designed, fabricated, and tested. The control was based on fine-tuning the magnitude of the bias voltage of the switches according to the difference between sensed and targeted capacitances. Intelligence could be programmed by periodically alternating the sign of the bias voltage when its magnitude...
A nanopore test circuit is proposed for single-strand DNA sequencing, which allows real-time sensing of the electric conductance of individual sections of a DNA strand as it is pulled through the nanopore by an electric current at a controlled speed. The test circuit is based on a planar microchamber with a nanochannel drilled through its multilayer graphene electrode by an electron beam. The nanochannel...
RF power, when approaching the handling capacity of microelectromechanical capacitive switches, was found to accelerate both the charging and discharging of the dielectric in the switches. The amount of acceleration appeared to be greater than what could be explained by self biasing and self heating. Since the long-term reliability of the switches is limited by dielectric charging, the RF power-handling...
A compact test structure and setup for ns-electroporation of biological cells is described. A CPW with defected ground assures impedance match with low dispersion or parasitic. The defected ground forms a microchamber for quick cell manipulation. The measured results along with EM analysis show that a 1-ns 0.1-V transmembrane potential can be induced. Although this is below the threshold for electroporation,...
Compact measurement setup and test structure for nanosecond electroporation of biological cells were demonstrated. The test structure was based on a coplanar waveguide with a defected ground structure that afforded broadband impedance match with little dispersion or parasitic. The defected ground structure with a 10-µm gap formed a microchamber to readily accept biological solutions and to allow the...
RF power, when approaching the handling capacity of microelectromechanical capacitive switches, was found to accelerate both the charging and discharging of the dielectric in the switches. The amount of acceleration appeared to be greater than what could be explained by self biasing and self heating. Since the long-term reliability of the switches is limited by dielectric charging, the RF power-handling...
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