Novel approaches to particle tolerant valves for use in drug delivery systems

Goettsche, T.; Kohnle, J.; Willmann, Michael; Ernst, H.; Spieth, Sven; Tischler, R.; Messner, S.; Zengerle, Roland; Sandmaier, H.

doi:10.1016/j.sna.2004.08.007

Cited by 25 publications

(18 citation statements)

References 2 publications

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“…19 A detailed discussion of microthrottles, their application in microthrottle pumps, and the operating principles of microthrottle pumps has been made previously, 20 therefore only a brief summary is provided here. Microthrottles necessitate the use of an elastomeric material to enable the formation of a variable cross-section microchannel segment.…”

Section: B Microthrottle and Mtp Operating Principlesmentioning

confidence: 99%

“…10,12 Blocking or gradual reduction in efficacy of the majority of micropumps and microvalves is a significant problem when the solution being pumped contains suspended phase particles. 19,31 Micropumps that are particle tolerant tend to not feature completely closing microvalves as integral components due to particles preventing full closure of the valve, 19 thereby reducing the micropump's efficiency. Peristaltic and nonmechanical micropumps have been developed which are capable of pumping particle laden solutions.…”

Section: Supernatant Hemoglobin Measurementmentioning

confidence: 99%

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Whole blood pumping with a microthrottle pump

et al. 2010

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We have previously reported that microthrottle pumps (MTPs) display the capacity to pump solid phase suspensions such as polystyrene beads which prove challenging to most microfluidic pumps. In this paper we report employing a linear microthrottle pump (LMTP) to pump whole, undiluted, anticoagulated, human venous blood at 200 μl min(-1) with minimal erythrocyte lysis and no observed pump blockage. LMTPs are particularly well suited to particle suspension transport by virtue of their relatively unimpeded internal flow-path. Micropumping of whole blood represents a rigorous real-world test of cell suspension transport given blood's high cell content by volume and erythrocytes' relative fragility. A modification of the standard Drabkin method and its validation to spectrophotometrically quantify low levels of erythrocyte lysis by hemoglobin release is also reported. Erythrocyte lysis rates resulting from transport via LMTP are determined to be below one cell in 500 at a pumping rate of 102 μl min(-1).

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Section: B Microthrottle and Mtp Operating Principlesmentioning

confidence: 99%

Section: Supernatant Hemoglobin Measurementmentioning

confidence: 99%

Whole blood pumping with a microthrottle pump

et al. 2010

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“…Li et al 15 reported a piezoelectric driven hydraulic amplification micro-valve which took PZT stack as the driving source, multilayer silicon and glass structure was selected, it turned out that the working frequency was higher than 1 kHz, but it required a complex fabrication process including 22 photolithography steps and particle tolerance is low as it utilize rigid plate as valve stopper. 16,17 In 2011, in order to simplify the fabrication progress and circumvent the sealing problem, X.S. Wu a yongliu@jlu.edu.cn 2158-3226/2016/6(4)/045112/9 6, 045112-1 © Author(s) 2016.…”

Section: Introductionmentioning

confidence: 99%

A normally-closed piezoelectric micro-valve with flexible stopper

et al. 2016

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In the field of controlled drug delivery system, there are still many problems on those reported micro-valves, such as the small opening height, unsatisfactory particle tolerance and high cost. To solve the above problems, a novel normally-closed piezoelectric micro-valve is presented in this paper. The micro-valve was driven by circular unimorph piezoelectric vibrator and natural rubber membrane with high elasticity was used as the valve stopper. The small axial displacement of piezoelectric vibrator can be converted into a large stroke of valve stopper based on hydraulic amplification mechanism. The experiment indicates that maximum hydraulic amplification ratio is up to 14, and the cut-off pressure of the micro-valve is 39kPa in the case of no working voltage. The presented micro valve has a large flow control range (ranging from 0 to 8.75mL/min).

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“…To address the issue of sample loading and manipulation a number of valve-type techniques have been developed and reviewed [20]. Magnetic microvalves can often be hybrid-integrated using permanent magnet to increase magnetic forces with less power consumption with movable membranes integrated coils [21][22][23].Though cylindrical and membrane valves are reported [24], to the best of author's knowledge use of PDMS-CoFe 2 O 4 nanocomposite membrane as a planer valve is not reported. The aim of the present study is to design and fabricate magnetically driven valve to control fluid flow and successful demonstration of the system.…”

mentioning

confidence: 99%

Magnetically controlled flexible valve for flow manipulation in polymer microfluidic devices

Bute

Sheikh

Mathe

et al. 2012

2012 1st International Symposium on Physics and Technology of Sensors (ISPTS-1)

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The paper describes design and fabrication of simple, magnetically actuated flexible polymer valve for flow manipulation in the microfluidic network. The valve is made up of a polymer composite. The CoFe 2 O 4 was embedded in PDMS (Polydimethylsiloxane) for making this polymer composite. The composites of different volume percentage loading of CoFe 2 O 4 were used and for each concentration valves of different thicknesses were fabricated, as thin rectangular membranes. This membrane was magnetized in the thickness direction and showed typical permanent magnet behaviour. For actuation of the valve the membrane was deflected by externally applied magnetic force which can close either of the channels. The flow manipulation and proper operation of the valve depends on thickness and percentage loading of magnetic material in membrane as well as dimensions of channel, chamber and membrane with respect to the location of outlet channels. The microfluidic channel was completely close for any fluid flow rate.

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Novel approaches to particle tolerant valves for use in drug delivery systems

Cited by 25 publications

References 2 publications

Whole blood pumping with a microthrottle pump

Whole blood pumping with a microthrottle pump

A normally-closed piezoelectric micro-valve with flexible stopper

Magnetically controlled flexible valve for flow manipulation in polymer microfluidic devices

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