Valve-less diffuser micropump for microfluidic analytical systems (original) (raw)
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Multiple Open-Channel Electroosmotic Pumping System for Microfluidic Sample Handling
Analytical Chemistry, 2002
The development of a novel, fully integrated, miniaturized pumping system for generation of pressure-driven flow in microfluidic platforms is described. The micropump, based on electroosmotic pumping principles, has a multiple open-channel configuration consisting of hundreds of parallel, small-diameter microchannels. Specifically, pumps with microchannels of 1-6 microm in depth, 4-50 mm in length, and an overall area of a few square millimeters, were constructed. Flow rates of 10-400 nL/min were generated in electric-field-free regions in a stable, reproducible and controllable manner. In addition, eluent gradients were created by simultaneously using two pumps. Pressures up to 80 psi were produced with the present pump configurations. The pump can be easily interfaced with other operational elements of a micrototal analysis system (micro-TAS) device with multiplexing capabilities. A new microfluidic valving system was also briefly evaluated in conjunction with these pumps. The micropump was utilized to deliver peptide samples for electrospray ionization-mass spectrometric (ESI-MS) detection.
Electroosmotically induced hydraulic pumping with integrated electrodes on microfluidic devices
2001
The theory behind and operation of an electroosmotically induced hydraulic pump for microfluidic devices is reported. This microchip functional element consists of a tee intersection with one inlet channel and two outlet channels. The inlet channel is maintained at high voltage while one outlet channel is kept at ground and the other channel has no electric potential applied. A pressureinduced flow of buffer is created in both outlet channels of the tee by reducing electroosmosis in the ground channel relative to that of the inlet channel. Spatially selective reduction of electroosmosis is accomplished by coating the walls of the ground channel with a viscous polymer. The pump is shown to differentially transport ions down the two outlet channels. This ion discrimination ability of the pump is examined as a function of an analyte's electrophoretic velocity. In addition, we demonstrate that an anion can be rejected from the ground channel and made to flow only into the field-free channel if the electrophoretic velocity of the anion is greater than the pressure-generated flow in the ground channel. The velocity threshold at which anion rejection occurs can be selectively tuned by changing the flow resistance in the field-free channel relative to the ground channel. The interconnecting channel structures that can be fabricated on microchips allow the rapid execution and automation of fluidic operations, such as valving, separation, dilution, mixing, and flow splitting, upon the proper application of a motive (driving) force. The integration of these simple operations to perform complete, multiple-step chemical assays is rapidly becoming a reality. 1,2 Such compact, monolithic devices potentially enjoy advantages in speed, cost, automation, reagent consumption, and waste generation compared to existing laboratory-scale instruments. Initial reports of these microfluidic devices focused on combining various electrokinetically driven separation methods, including microchip electrophoresis, 3-7 gel electrophoresis, 8-10 micellar electrokinetic chromatography (MEKC), 11,12 and openchannel electrochromatography (OCEC), 13 with fluidic valving to introduce sample plugs into a separation channel. Other operations, however, have quickly been integrated with the separations and fluidic valving on these microchips. For example, integrated devices with mixers/diluters for precolumn 14-16 and postcolumn 17,18 analyte derivitization, DNA restriction digests, 15 enzyme assays, 19,20 and PCR amplification 21,22 have been added to the basic design. Integrated mixers which can perform solvent programming for both MEKC 23 and OCEC 24 have also been demonstrated. In addition to these reports, flow splitting at a tee intersection on a microchip has been demonstrated for the generation of pressure-induced flow to a chip-electrospray interface through a field-free channel. 25 Normally, at a tee intersection (Figure 1A) when a potential is applied between the separation and ground reservoirs, no flow will be generated in the field-free (electrically floating) channel (ff), assuming that the potential is homogeneous along the walls of the separation and ground channels and that all dimensions exceed the double-layer thickness. If, however,
Pumping of mammalian cells with a nozzle-diffuser micropump
Lab on a Chip, 2005
We discuss the successful transport of jurkat cells and 5D10 hybridoma cells using a reciprocating micropump with nozzle-diffuser elements. The effect of the pumping action on cell viability and proliferation, as well as on the damaging of cellular membranes is quantified using four types of well-established biological tests: a trypan blue solution, the tetrazolium salt WST-1 reagent, the LDH cytotoxicity assay and the calcium imaging ATP test. The high viability levels obtained after pumping, even for the most sensitive cells (5D10), indicate that a micropump with nozzle-diffuser elements can be very appropriate for handling living cells in cell-on-a-chip applications.
A high-performance silicon micropump for disposable drug delivery systems
Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090), 2001
This paper describes the design, fabrication and experimental results of a new, low cost, high-performance silicon micropump developed for a disposable drug delivery system. The pump chip demonstrates linear and accurate ( 5%) pumping characteristics for flow rates up to 2 ml/h with intrinsic insensitivity to external conditions. The stroke volume of 160 nl is maintained constant by the implementation of a double limiter acting on the pumping membrane. The actuator is dissociated from the pump chip.
Current micropump technologies and their biomedical applications
Microsystem Technologies, 2009
This paper briefly reviews recent research and developments of micropump designs with a particular emphasis on mechanical micropumps and summarizes their applications in biomedical fields. A comprehensive description of the actuation schemes, flow directing concepts and liquid chamber configurations for micro pumping is provided with illustrative diagrams. Then, a comparative study of current mechanical micropump designs highlighting their advantages and limitations for various applications is presented, based on performance criteria such as actuation voltage and power consumption, ranges of operating frequency and maximum flow rate and backpressure. This study compiles and provides some basic guidelines for selection of the actuation schemes and flow rate requirements in biomedical applications. Different micropumps in biomedical applications, such as blood transport and drug delivery also have been reviewed.
Manipulation and Flow of Biological-Fluids in Straight Channels Micromachined in Silicon
Clinical Chemistry
Analysis of minute sample volumes is a major analytical challenge that requires an understanding of fluid flow in microstructures. Accordingly, flow dynamics of biological fluids and cell suspensions in straight glass-capped silicon microchannels (40 to 150 m wide, 20 and 40 m deep) were studied. We demonstrated that these microstructures are appropriate components for microfluidic analytical devices. Different fluids were easily manipulated in the microchannels, and measurements of flow rate as a function of pressure for whole human blood, serum, plasma, and cell suspensions revealed non-Newtonian behavior. By means of micromachined filters (5 m) located in channels, blood cells and microparticles were effectively separated from nanoliter-sized samples, clearly indicating the future role of microstructures for a variety of analytical purposes.
A positive displacement micropump for microdialysis
Mechatronics, 1998
Miniature~uid pumps\ measuring 04×3×0 mm\ have been microfabricated with silicon\ glass\ and polyimide[ Pumps have been tested with deionized water and 09) glycerol solutions as the working solutions[ The pumps have been operated with a pneumatic drive or a pie! zoelectric drive[ Flow rates from 9[0 to 009 ml min −0 have been achieved[ The maximum pressure generated by the pumps was 45 cm of water[ Pumps have been operated with a dialysis probe and with a microchannel load[ The pump lifetime is limited by the degradation in the performance of the polyimide components in the pump[ The power consumption was less than 0 mW at a drive frequency of 09 Hz[ Þ 0887 Elsevier Science Ltd[ All rights reserved[
Sensors and Actuators B: Chemical, 2003
Monolithic elastomer membrane valves and diaphragm pumps suitable for large-scale integration into glass micro¯uidic analysis devices are fabricated and characterized. Valves and pumps are fabricated by sandwiching an elastomer membrane between etched glass uidic channel and manifold wafers. A three-layer valve and pump design features simple non-thermal device bonding and a hybrid glass-PDMS¯uidic channel; a four-layer structure includes a glass¯uidic system with minimal¯uid-elastomer contact for improved chemical and biochemical compatibility. The pneumatically actuated valves have <10 nl dead volumes, can be fabricated in dense arrays, and can be addressed in parallel via an integrated manifold. The membrane valves provide¯ow rates up to 380 nl/s at 30 kPa driving pressure and seal reliably against¯uid pressures as high as 75 kPa. The diaphragm pumps are self-priming, pump from a few nanoliters to a few microliters per cycle at overall rates from 1 to over 100 nl/s, and can reliably pump against 42 kPa pressure heads. These valves and pumps provide a facile and reliable integrated technology for¯uid manipulation in complex glass micro¯uidic and electrophoretic analysis devices. #
Fabrication and Performance Testing of Disposable Micropump Suitable for Microfluidic Chip
2006
Micropumps represent one of the major components in microfluidic technology. This paper describes the design, fabrication and performance testing of a simple, compact, inexpensive and disposable micropump suitable for microfluidic chip applications. The proposed pump is made of polymeric materials, PMMA and PVC, and fabricated using a direct-write CO2 laser machine. The size of pump body is 5 mm and