A disposable thermopneumatic-actuated micropump stacked with PDMS layers and ITO-coated glass

A thermopneumatic-actuated polydimethylsiloxane (PDMS)-based micropump has been fabricated and its properties have been characterized. Diffusers are used as flow-rectifying elements instead of passive check valves. The advantages of the proposed micropump are the low cost fabrication process and the transparent properties of the PDMS and indium tin oxide (ITO)-coated glass. We present a PDMS micropump that is easily integrated with in-channel PDMS microvalves on the same substrate. The flow rate of the micropump increases linearly with increasing applied pulse voltage to the ITO heater with resistance of 6.54 kΩ. The peak flow rate of 78 nl/min is observed at the duty ratio of 10% for the applied pulse voltage of 55 V at 6 Hz.     

驱动参数对串联和并联压电微泵特性影响比较研究

无阀压电微泵在微流体驱动及芯片上的实验室等方面有着广泛的应用。为了比较串联、并联无阀压电微泵性能差异,采用玻璃湿法腐蚀工艺,以玻璃为基体,制造出含有串联、并联腔体结构压电微泵,并采用聚二甲基硅氧烷(PDMS)对微泵进行封装,两种微泵泵腔和扩张/收缩微流道尺寸相同。设计出不同驱动信号波形、电压、相位、占空比和对称性组合,并将不同驱动方式组合应用于两种微泵的流量和压力性能测试。结果显示:驱动条件对两种微泵性能有较大影响;两种微泵的流量和压力随着驱动电压升高均呈现增大趋势;三角波驱动条件下两种微泵性能优于正弦波和方波驱动;驱动波形相位、占空比和对称性对串联微泵性能的影响较并联微泵大。试验同时得出:P1和P2两个腔体在正弦-正弦信号组合驱动下,串联微泵的流量和压力值在相位差为±180°时达到最大;并联微泵则在相位差为0°时达到最大,与并联和串联微泵结构及工作原理相一致;所有驱动条件组合下,并联微泵性能优于串联微泵。试验测得并联微泵的最大流量和压力分别为173μL/min和490.8 Pa,串联微泵的最大流量和压力分别为83.1μL/min和190.3 Pa。     

热驱动薄膜式微型泵性能的初步分析

对热驱动微型泵的关键部件——铝—硅复合膜片进行了数值计算和分析。发现存在一个合适的交变加热频率范围 ,使单位时间泵腔体积变化量达到最大 ;铝膜形状取为圆形比环形有利于得到更大的泵腔变形体积。减薄硅膜厚度和增加铝膜的厚度也能增大泵腔体积变化量     

Optimisation Design of a Piezoelectric Micropump

A new aluminium based valveless fluid micropump is manufactured by the micromachining method. The pump consists of two fluid-diffuser/nozzle elements on each side of a chamber with an oscillating diaphragm which is actuated with a piezoelectric disk. The two simultaneous vibrating diaphragms produce a large oscillating chamber volume. To obtain the optimal structural parameters at the design stage of the pump, the ANSYS simulation method is used. The pump prototype with two aluminium diaphragms of ○ (with a slash) 10 mm 3 0.1 mm has been simulated. The chamber oscillating volume can be as large as 800 ml for water pumping.     

A study on the MHD (magnetohydrodynamic) micropump with side-walled electrodes

This paper presents the continuous flow MHD(magnetohydrodynamic) micropump with side walled electrodes using Lorentz force, which is perpendicular to both magnetic and electric fields, for the application of microfluidic systems. A theoretically simplified MHD flow model includes the theory of fluid dynamics and electromagnetics and it is based upon the steady state, incompressible and fully developed laminar flow theory. A numerical analysis with the finite difference method is employed for solving the velocity profile of the working fluid across the microchannel under various operation currents and magnetic flux densities. In addition, the commercial CFD code called CFD-ACE has been utilized for simulating the MHD micropump. When the program was run(CFD-ACE), the applied current and magnetic flux density were set to be the variables that affected the performance of the MHD micropump. The MHD micropump was fabricated by using MEMS technology. The performance of the MHD micropump was obtained by measuring the flow rate as the applied DC current was changed from 0 to 1mA at 4900 and 3300 Gauss for the electrodes with the lengths of 5000, 7500 and 10000 μm, respectively. The experimental results were compared with the analytical and the numerical results. In addition, with the theoretical analysis and the preliminary experiments, we propose a final model for a simple and new MHD micropump, which could be applicable to microfluidic systems. This paper was recommended for publication in revised form by Associate Editor Seungbae Lee Bumkyoo Choi received a B.S. degree in mechanical engineering, M.S. in mechanical design engineering from Seoul National University, Seoul, Korea in 1981 and 1983 respectively, and PhD in engineering mechanics from the University of Wisconsin, Madison in 1992. From 1992 to 1994, he was a technical staff member of CXrL (Center of X-ray Lithography) in the University of Wisconsin where he developed a computer code for thermal modeling of X-ray mask membrane during synchrotron radiation. He is currently a professor in the Dept. of Mechanical Engineering of Sogang Univ., Seoul, Korea. His research interest includes microelec-tromechanical system (MEMS), micromatching and microfabrication technologies, and modeling issues. Sangsoo Lim received a B.S. degree in mechanical engineering from Sogang University, Seoul, Korea in 2005. He currently works at Hyundai Motors.     

热驱动薄膜式微型泵的数值模拟

文中给出了对一种热驱动薄膜式微泵的数值模拟的方法与结果。     

Fluid actuation for a bio-micropump powered by previously frozen cardiomyocytes directly seeded on a diagonally stretched thin membrane

Recently, various microfluidic devices have been developed. However, they are difficult to use in vivo because they require an external energy source such as electricity. Taking a different approach, we previously developed a bio-micropump powered by cardiomyocyte sheets that utilizes only glucose in the medium as chemical energy (Tanaka et al., Lab Chip 6(3), 362-368) [5]. To fabricate the pump, we require fresh primary neonatal rat cardiomyocytes. This operation is complicated and inconvenient because the experiments can only be carried out when rats are obtained. If commercially available frozen cardiomyocytes could be used, the experiments would become easier because frozen cells can be thawed and used any time. One technical problem with this new approach is that the force generated by thawed frozen cardiomyocytes is weak and it is difficult to fabricate a contiguous cell sheet using them. In the present study, we report that we have developed an actuator for fluid actuation for a bio-micropump using thawed frozen cardiomyocytes having a new structure, by using a thin membrane and a cubic block to collect the cardiomyocyte force and communicate it to fluid. We were able to demonstrate fluid motion in a microchannel connected to a diaphragm chamber induced by the synchronously pulsating cardiomyocytes. This new approach reduces the necessity of using animals for the experiments, because frozen cells may be used.     

Micro devices for a cerebrospinal fluid (CSF) shunt system

This paper reports a novel cerebrospinal fluid (CSF) shunt system for the hydrocephalus patients. The CSF shunt system consists of a micro telemetry pressure sensor, an electromagnetic micropump and a controller. The pressure sensor has a flexible p+ diaphragm and a planar copper coil that construct an LC resonant circuit. The cerebrospinal pressure is measured from the phase shift at the resonance frequency. The micropump consists of an actuator diaphragm and a pair of passive valves. Each device is fabricated by micromachining technology and tested to obtain the characteristic. The feasibility of the proposed shunt system is evaluated with the in vitro performance test.     

TiNi／Si复合膜微驱动器原理及结构参数优化

应用有限元方法对TiNi/Si复合膜微驱动器的结构设计进行了分析，因TiNi和Si之间的热膨胀系数差别很大，溅射在Si(100)衬底上的TiNi膜，当从晶化的高温降下来时会积聚很大的热应力，这种微驱动器，就是利用了TiNi的形状记忆效应而引起的这些应力的释放与恢复从而引起复合膜的振动，图形化TiNi薄膜制成加热电阻条件为自加热电阻，可降低功耗，提高响应速度，简化结构， 但作为驱动单元的一部分，其图形化的结构参数对复合膜的挠度有很大的影响，通过结构参数优化，可使复合膜的中心挠度值达到最大，从而提高驱动器的性能。     

FIA系统的设计

报道了一种 FIA系统。该 FIA系统集成了 p H-ISFET传感器、微型泵以及传感器信号处理电路 ,体积实现微型化。实验结果表明 ,本系统具有响应速度快、稳定可靠等特点 ,且仅需微量待测液体