A system-level prototype for EWOD driving was proposed and built, to aim the goal of droplet manipulation in 2D large scaled EWOD chip for biological detection.

When a 2D large scale EWOD chip is applied into application, there is still challenge in control of independent electrode for flexible applications. Droplet residues on electrode or any defects in the dielectrics would cause failures of droplet manipulation or detection accuracy. Therefore, effective control of electrodes, and discovery of the sites of the bugs and real-time routing for dodging of them are important for biological detections. We proposed a direct address and passive controlling method with N+M pins for M+N electrodes, and an electrical impedance-based sensing method for the bug finding. Lee algorithm was applied to automatically route droplet with real-time feedback of the bugs in the 2D EWOD chip with 10´10 electrode matrix. Hardware and software were developed applicable for 2D large scale EWOD chips.

Fig. 1 shows the schematic and picture of the system and the signal flow among the circuit components. Fig. 2 demonstrates the manipulation of multiple droplets simultaneously without conflict. Fig.3 gives the detection of the sites and sizes of the droplet residue larger than 40% of that of the electrode. Fig.4 expresses the real-time routing to dodging the bugs successfully.

  This paper reports a novel biosensor based on shear horizontal surface acoustic wave(SH-SAW) applied in biological detection. we designed a surface acoustic wave resonator as biosensor and integrated it with a waterproof fixture, in which there is a micro-fluidic channel insuring the smooth of liquid flowing, and guarantee the stability during the biological reaction. In this paper, we have studied the feature of the device in liquid-phase, the experimental result indicates that a larger value of phase shift (3 degree) is realized compared with pioneer works[1].
  SAW biosensors, as core part of the bio-detection system are powerful and promising in various fields. Particularly for clinical analysis and biochemical, the SH-SAW biosensors are good candidates benefiting from high sensitivity and good repeatability in liquid phase. In this paper, we present a novel SH-SAW biosensor, the device geometry schematically is shown in Fig.1. A 36° rotated Y-cut X propagation lithium tantalate (LiTaO3) piezoelectric single crystal chip is selected as substrate and Au is selected for IDT fingers, electrode and the area of bio-probe grow respectively. In addition, the microfluidics inlet and outlet channels were fabricated by PDMS micro molding technique to insure the smooth flowing of the liquid flow in the sensitive area. Fig.2 and 4 show the inner structure of the PDMS micro-fluidics channel layer and the assembled fixture respectively. Compared to our group's previous research output[1-2], the SH-SAW biosensor reported in this paper posses several advantages: (1) avoid the volatilization of the solution; (2) ease of device miniaturization; (3) the fixture we have designed offers a confined space, which minimizes the air influence , and hence guarantees more enough times of biological reactions performed at certain volume solution provided each time.
  The SH-SAW based bio-chip (Fig.1) consists of two sets of gold input and output IDTs mounted on the surface of the LiTaO3 substrate. The SH-SAW is excited by an input electrical signal applied at the input IDTs, and then propagates on the piezoelectric substrate through the delay line and is converted back to an electrical signal[3], while the wave is potentially sensitive to the mass loading on the surface, therefore, the signal phase will shift when the aptamers are fixed on the surface through Au-S bond. The main displacement component of the SH-SAWs is perpendicular to the direction of the propagation and parallel to the propagation surface, and the longitudinal waves will not be reflected at the solid/liquid interface[4], as the biological reactions occur in liquid-phase, so the waves can propagate with minimal dissipation of energy to a liquid at the surface[5]. The detailed parameter of the device can be found in table Ι.
The measurement system(Fig.7) consists of an Aglient E5080A network analyzer connected to SMA adapter, the spectrogram of the bio-chip is shown in Fig.5. In the experiments, we fixed the aptamers on the sensitive area by sulfhydryl self-assembled method, the phase shift data was analyzed by Matlab and the picture is shown in Fig.6, the phase shift is about 4.5°, and the stability time is less than 10 minutes, which is better than our previous research.

This talk will give a systematic study for the ultra-precision machining technology for generating various optical microstructures, such as micro V-groove for optical fiber connectors, microlens array for microfluidic microcavity, etc. which includes the machining mechanism, tool path generation, modeling and simulation of surface generation, machining error prediction, process optimization, etc. A series of methods and approaches are also presented to measure and characterize such optical microstructures. The research work aims to provide an enabling solution for producing optical microstructures in high precision and efficiently.

Setting a target on implantable medical devices such as respiration-supporting pacemaker for amyotrophic lateral sclerosis (ALS), we develop an energy harvester that could earn electrical power from the mechanical motion of liquid droplets on an electrical charged plate called “electret.” A PDMS sheet with micro fluidic channels is laminated onto a silicon substrate with built-in permanent electrical charges. A pair of capacitive electrodes is formed in the sealed fluidic channels, in which water droplets are displaced back and forth due to the applied pressure that simulates the motion of heartbeat. Typical output power of 0.17 µW/cm² is obtained at 0.47 Hz. Analytical model suggests that the extension of the electret plate to ~ 6 cm² delivers 1 mW power, which is sufficient to drive the implantable medical devices.

With the rapid development of MEMS (Micro-electro-mechanical Systems) fabrication technologies, manifolds microelectrodes with various structures and functions have been designed and fabricated for applications in biomedical research, diagnosis and treatment through electrical stimulation and electrophysiological signal recording. The flexible MEMS microelectrodes exhibit multi-aspect excellent characteristics, such as: lighter weight, smaller volume, better conforming to neural tissue and lower fabrication cost. In this talk, we mainly reviewed key technologies on flexible MEMS microelectrodes for neural interface in recent years, including: design and fabrication technology, flexible MEMS microelectrodes with fluidic channels and electrode-tissue interface modification technology for performance improvement. Furthermore, the future directions of flexible MEMS microelectrodes are discussed.