Transpiration-based micropump for delivering continuous ultra-low flow rates

Namasivayam, Vijay; Larson, Ronald G.; Burke, David T.; Burns, Mark A.

doi:10.1088/0960-1317/13/2/314

Cited by 48 publications

(42 citation statements)

References 23 publications

(25 reference statements)

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“…Systems composed of a multitude of micro-channels with open outlets can be used for parallel assays and enable high throughput microfluidics (Juncker et al 2002;Park et al 2006;Zimmermann et al 2007;Namasivayam et al 2003). On the other hand, the use of open outlets is the cause of side effects mostly related to evaporation and contamination.…”

Section: Introductionmentioning

confidence: 99%

3D visualization of convection patterns in lab-on-chip with open microfluidic outlet

Gazzola

Scarselli

Guerrieri

2009

Microfluid Nanofluid

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Open-outlet microfluidics is getting more and more attention, thanks to the generation of capillarity-driven flows which simplify the connection with the macroworld. It is known that convection flows are generated at the interface with air, i.e., the meniscus. Several works have investigated evaporation-induced convection, but its effect on particle position control in open-outlet biodevices is still not characterized. In this paper, we present the results of 3D measurement of particle traces near the meniscus in an open-outlet vertical 400 lm micro-channel filled with a water-based saline solution. Using a standard optical microscope and a system of mirrors, we observe the 3D position of individual micro-beads floating in the solution, in a way akin to particle image velocimetry technique. A single vortex is generated at the meniscus and occupies the whole region under observation at a distance of 1.5-2.7 mm from the meniscus. The generation of the convection pattern and the vortex rotational speed are described. The convection patterns disappear when evaporation is inhibited, while both the vortex generation and the rotational speed are faster for highly saline solutions. These results are relevant to the design of biochips which require control of the particle position in a fluid since they emphasize that in open-outlet microfluidic systems not only the gravitational fall but also the convection drag must be counteracted.

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Section: Introductionmentioning

confidence: 99%

3D visualization of convection patterns in lab-on-chip with open microfluidic outlet

Gazzola

Scarselli

Guerrieri

2009

Microfluid Nanofluid

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“…glass for the "floor" and "side-walls") separated from the air-circulating network by a thin membrane of a chosen porous materials. Similar sandwich micro-constructions have been used in related contexts [12,13,14].…”

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confidence: 99%

Microevaporators for Kinetic Exploration of Phase Diagrams

et al. 2006

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We use pervaporation-based microfluidic devices to concentrate species in aqueous solutions with spatial and temporal control of the process. Using experiments and modelling, we quantitatively describe the advection-diffusion behavior of the concentration field of various solutions (electrolytes, colloids, etc) and demonstrate the potential of these devices as universal tools for the kinetic exploration of the phases and textures that form upon concentration.PACS numbers: 07.90.+c, 64.75.+g Determination of the phase diagram of multicomponent systems is of importance in many realms: industrial formulation, protein cristallization, bottom up material assembly from spontaneous ordering of surfactant, polymeric or colloidal systems [1,2,3]. Depending on the application, one may want to access only the equilibrium phase diagram or gain additional information as to the metastable phases that can appear for kinetic reasons. Methods to reach these goals often imply tedious and systematic measurements, requiring for screening purposes the use of robotic platforms. Two generic strategies consist in varying (in space or time) the temperature of samples of given concentrations on the one hand, and on the other hand isothermal concentration by either removal of the solvent (osmosis, drying), external action on the solutes (sedimentation or dielectrophoresis for colloids), or studies of spontaneous interdiffusion in contact experiments.In this Letter we introduce microfluidic tools for controlled isothermal concentration of a wide range of systems, covering solutions of ions, polymers, proteins, surfactants and colloidal suspensions. Our work is inspired by recent observations [4,5] that in standard microsystems built of PolyDiMethylSiloxane (PDMS), spontaneous water permeation through the PDMS matrix induces flows that can be used to concentrate colloids. Taking a step further, we have engineered specialized microgeometries that allow us to control spatially and temporally the evaporation process as well as the resulting concentration of solutes. Their parallel implementation in microfluidic format could open the way to fast screening methods.After a brief description of the micro-devices, we demonstrate first our control of the concentration process on dilute aqueous solutions of fluorescein and nanoparticles in a simple geometry. We then discuss how microfabrication permits to widen the range of possibili- ties and applications of such devices. As a study case, we report controlled nucleation and growth of crystals of potassium chloride (KCl), and show how such experiments provide quantitative information on various thermodynamic quantities (solubility, crystal density) as well as kinetic features (sensitive to the rate of concentration).The devices -The devices used in this paper are twolayer PDMS on glass microsystems (Fig. 1) (fabrication procedure detailed in [6]). The microchannels of the bottom layer are filled with the solution of interest, while air (at controlled humidity) is circulated through the microchan...

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“…A more detailed description can be found in [1]. A sketch of the SFM-probe configuration is schematically shown in Fig.…”

Section: Theorymentioning

confidence: 99%

“…Compared to other mechanisms used in micro fluidics [1], the concept of evaporation driven pumps enables low and continuous flow rates. Its main application is currently in lab-on-a-chip research [2], where it is used for e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaporation based micro pump integrated into a scanning force microscope probe

Heuck

Hug

Akiyama

et al. 2008

Microelectronic Engineering

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A micro pump was integrated into a scanning force microscope probe for circulating liquid through its hollow cantilever and tip. The interior cross section of the cantilever was 2.25 lm Â 3.75 lm. All fluidic parts were made of SiO 2 , while the tip apex was made of Si 3 N 4 . The key fabrication techniques were silicon wafer bonding and wet-oxidation. The pumping mechanism was relying on the enhanced evaporation at an enlarged water/air interface at the exit of the microchannel. Capillary forces continuously wetted this interfacial area, thus drawing the liquid through the system. At room temperature, a pump rate of 11 pl s À1 was experimentally evaluated. The observed temperature dependence of the pump rate could be qualitatively understood by a plain model calculation.

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Transpiration-based micropump for delivering continuous ultra-low flow rates

Cited by 48 publications

References 23 publications

3D visualization of convection patterns in lab-on-chip with open microfluidic outlet

3D visualization of convection patterns in lab-on-chip with open microfluidic outlet

Microevaporators for Kinetic Exploration of Phase Diagrams

Evaporation based micro pump integrated into a scanning force microscope probe

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