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Development of compact and low-cost electronic circuits in the biosensor field is an essential demand. Especially, the design of noise reduction sections plays an important role in the measurement ...

This paper presents the design, optimization, fabrication and characterization of a symmetrical two-axis tilt angle sensor. The sensor consists of a globe-calotte-shaped excitation electrode and tw...

This paper reports a study on developing of a protein detection biochip based on interdigitated array electrodes (IDAEs) capacitive immunosensor. The protein after being preconcentrated in a detection region will be selectively captured and detected by the capacitive immunosensor. Using electrical impedance spectroscopy operated at high-frequency in the range of 100 kHz–1 MHz, the capacitance of the gold electrode is determined and the antibody surface modification steps can be also monitored. The experiment results show the capacitance changes in accordance with the adding biochemical layer on gold electrodes for each step of the antibody surface modification. In particular, the total impedance operated at 1 MHz frequency has been seen to change from 2.1 kΩ of bare chip (before antibody surface modification) to 8 kΩ after antibody surface modification process while the serial capacitance is recorded to reduce steadily from 450 pF to 55 pF. Also, the efficiency of protein chip was investigated by implementing the measurement of 10 µM BSA with and without preconcentration process. The measurement results have shown the sensitivity increasing significantly after the protein is preconcentrated in this chip. The results demonstrate high efficiency of protein detection can be achieved by operating high frequency capacitive measurement on IDAEs capacitive immunosensor.

This paper presents a design optimization and validation of a two-axis cylindrical capacitive tilt angle sensor. The proposed sensor includes of five electrodes symmetrically arranged surrounding a...

This paper presents the design, fabrication, and characterization of a two-axis tilt angle sensor based on the air/liquid two-phase dielectric capacitive sensing structure. The sensor consists of f...

In the recent decades, droplet-based microfluidics has emerged as a promising research area which covers various applications in a broad spectrum of fields such as chemical reactions, drug discovery, molecule synthesis and cell biology. This study proposes the implementation of a microfluidic droplet generating prototype using the popular flow-focusing geometry. The proposed system is fabricated based on a rapid prototyping technique, which significantly simplifies the fabrication process, reduces the production cost and shortens the time-to-market as compared with traditional techniques. The functionalities and characteristics of the prototype were carefully verified by simulations and practical experiments. The obtained results showed that the generation of droplets could be precisely controlled by adjusting the flow rate ratio between the dispersed phase and the continuous phase.

This paper presents a design of a compact system for low concentration protein detection based on an effectiveness concentrator which is relied on exclusion-enrichment effect (EEE) and a highly sensitivity lock-in impedance measurement technique. Experiment results suggested that protein concentration of down to sub-nanomolar can be detected by the proposed system.

This paper presents a dielectrophoresis (DEP) enrichment microfluidic platform with built-in antibody-based capacitive sensor for tumor rare cells detection. We take the advantages of the effective DEP actuation, the high selectivity property of antibody for rare cell immobilization, and the high sensitivity of differential capacitive sensing for quantitatively reading out, to produce advanced platform, toward single tumor cell detection for the rapid laboratory tests of cancers diagnoses and other metabolic diseases applications.

This paper presents the design, fabrication and characterization of a two-axis tilt angle sensor based on dielectric liquid capacitive sensing structure. The sensor consists of five electrodes, including one electrode serves as the exciting electrode and two pairs of sensing electrodes arranged at identified positions surrounding a plastic tube, which is partly filled with dielectric liquid. With this unique arrangement, the proposed sensor can detect two components of tilt angle in x-axis and x-axis, simultaneously. A computational multiphysic simulation and experimental measurements study the performance of the sensor. The numerical simulation is carried out with a finite element analysis using COMSOL Multiphysics. A prototype of the sensor was fabricated and its performance was evaluated. The tilt angle sensor is employed on a PCB with conditioning circuit, which consists of a 170 kHz sine wave generator, pre-amplifiers, rectifiers and low pass filters. Experiment results confirmed the performance of the sensor to detect tilt angle in both x-axis and y-axis. Tilt angle sensitivities to x-axis and y-axis are 16.5 mV/degree and 57 mV/degree, respectively, with cross-axis sensitivity less than 5.5% in the linear range.