Piezoelectric titanium based microfluidic pump and valves for implantable medical applications

Bussmann, Agnès; Durasiewicz, Claudia Patricia; Kibler, S.; Wald, Christian

doi:10.1016/j.sna.2021.112649

Cited by 24 publications

(29 citation statements)

References 30 publications

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“…Since experimental leakage rates of the coated microvalves do not differ from the basic design, beneficial sealing properties as a result of the Parylene-C coating cannot be derived to this date. However, the comparison of the measured leakage rates to former investigations of NO valves with soft sealing components [14] reveals that the microvalve variants presented here achieve similar leakage rates with significantly lower standard deviations. Therefore, the micromachined trenches are proven suitable for the fabrication of a microvalve with increased reliability with a view to sample-to-sample variation of the exhibited leakage rate due to higher manufacturing precision of the valve seat compared to microvalves comprising an O-ring soft sealing.…”

Section: Experimental Characterizationsupporting

confidence: 51%

“…Most recently, we reported on the development of an NO microvalve for microfluidic implants [14], showing low leakage rates ((10.9 ± 28.1) µ L/min) as well as high flow rates in open state ((27.5 ± 5.3) mL/min) at a water pressure of 20 kPa. Insufficiently low manufacturing precision of the integrated O-ring sealing led to large sample-to-sample variations and induced various failure mechanisms of the microfluidic device.…”

Section: Microvalve Design Operation and Fabricationmentioning

confidence: 99%

“…While passive microvalves show diode-like fluid path opening at forward pressure and closing at backwards pressure [3] or serve as constant flow regulators [4], active microvalves based on piezoelectric [5,6], shape memory alloy [7,8], phase change [9,10], or other actuation mechanisms [3] allow for opening and closing of fluid paths in an arbitrary, hence flexible and dedicated manner. External control of active microvalves enables functionalities like controlled dosing of drugs [11,12], mixture of reagents [10,13], confinement of a high pressure fluid to other volumes [14,15], as well as handling of small fluid volumes in medical devices and implants [16][17][18][19][20]. Such active flow path control can be achieved by piezoelectrically actuated microvalves, which are either of normally open (NO) or normally closed type, defined by their function in a non-actuated state [3], and typically consist of a piezoactuator, a valve diaphragm, and a valve seat [2].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, medical applications like wearable drug dosing devices or implants require hermetic sealing of the device, low risk of component failure, as well as biocompatibility of all wetted surfaces [21]. Most recently, we reported on the development of an NO microvalve for microfluidic implants [14], showing low leakage rates ((10.9 ± 28.1) µL/min) as well as high flow rates in open state ((27.5 ± 5.3) mL/min) at a water pressure of 20 kPa. Insufficiently low manufacturing precision of the integrated O-ring sealing led to large sample-to-sample variations and induced various failure mechanisms of the microfluidic device.…”

Section: Introductionmentioning

confidence: 99%

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Piezoelectric Normally Open Microvalve with Multiple Valve Seat Trenches for Medical Applications

et al. 2021

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Microfluidic systems for medical applications necessitate reliable, wide flow range, and low leakage microvalves for flow path control. High design complexity of microvalves increases the risk of possible malfunction. We present a normally open microvalve based on energy-efficient piezoelectric actuation for high closing forces and micromachined valve seat trenches for reliable valve operation. A comprehensive investigation of influencing parameters is performed by extensive fluidic 3D finite element simulation, derivation of an analytical closed state leakage rate model, as well as fabrication and test of the microvalve. Additional valve seat coating and a high force actuator are introduced for further leakage reduction. The microvalve has a wide-open flow range as well as good sealing abilities in closed state. Extensive fatigue tests of 1 × 106 actuation cycles show that additional coating of the valve seat or increased actuator strength promote sealing performance stability. Analytical calculations of leakage are suitable to estimate experimentally obtained leakage rates and, along with computational fluidic dynamic (CFD) simulations, enable future microvalve design optimization. In conclusion, we demonstrate that the presented normally open microvalve is suitable for the design of safe and reliable microfluidic devices for medical applications.

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Section: Experimental Characterizationsupporting

confidence: 51%

Section: Microvalve Design Operation and Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Piezoelectric Normally Open Microvalve with Multiple Valve Seat Trenches for Medical Applications

et al. 2021

Self Cite

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“…For microfluidic devices, it is vital to select an appropriate driving method. In general, microfluidic driving methods include electrostatic actuation (H. Kim et al, 2015;Teymoori & Abbaspour-Sani, 2005), electromagnetic actuation (Rosenberger, 1930;X.-D. Zhang et al, 2020), shape memory actuation (Saren et al, 2018;Ullakko et al, 2012), and piezoelectric actuation (Bussmann et al, 2021;J. Kan et al, 2008;Wu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

A novel valve-less piezoelectric micropump generating recirculating flow

Chen

Gui

et al. 2021

Engineering Applications of Computational Fluid Mechanics

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Microfluidic devices or systems to generate recirculating flow are increasingly utilized in the fields of chemistry, biomedicine, biology, with bottlenecks in integration and miniaturization needed a breakthrough. Here, a concept for a highly integrated valve-less piezoelectric micropump generating recirculating flow (VPMGRF) is proposed, simultaneously realizing innovation in theory and method. Based on fluid inertiaand energy dissipation of vortexes, a novel double-loop tube was designed to achieve fluid flow in different directions along various paths, with the flow characteristics at different cross-sectional areas explored through computational fluid dynamics (CFD). Afterwards, as valve bodies, the double-loop tubes were connected with a piezoelectric-actuated chamber to constitute the VPMGRF, which was followed by establishing a theoretical model of the vibration, fluid dynamics, and net flow rate. Eventually, experimental results showed that VPMGRFs could generate internal recirculating flow and had a pump effect. The maximum net flow rate reached 5.19 mL/min at 8 Hz, corresponding to a vibrator amplitude of 35 μm and an output pressure amplitude of 4.27 kPa. Furthermore, the larger the characteristic length of the cross section, the greater the amplitude of the vibrators, the larger the amplitude of output pressure, and the slower the flow rate.

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Design and numerical study of a bidirectional acoustic microfluidic pump enabled by microcantilever arrays

Chen,

Zheng,

Xie

et al. 2023

Electrophoresis

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Microfluidics offers a versatile and promising platform for various applications in biomedical and other fields, boasting cost‐effectiveness, rapid analysis time, and a compact equipment footprint. However, achieving controlled and versatile microfluidic motion within implantable devices presents a significant challenge. In this study, we propose a novel bidirectional micro‐pump design that leverages two sharp‐edge microcantilever arrays, driven by ultrasound, to enable selective flow direction by manipulating the ultrasound frequency. Through systematic numerical simulation, we demonstrate the feasibility of this design and further optimize its performance through comprehensive parametric analysis. This work provides valuable guidance for the practical development of sharp‐edge‐based acoustic micro‐pumps, particularly for potential implantable applications such as controlled drug release and in vivo sampling for advanced diagnostics.

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Piezoelectric titanium based microfluidic pump and valves for implantable medical applications

Cited by 24 publications

References 30 publications

Piezoelectric Normally Open Microvalve with Multiple Valve Seat Trenches for Medical Applications

Piezoelectric Normally Open Microvalve with Multiple Valve Seat Trenches for Medical Applications

A novel valve-less piezoelectric micropump generating recirculating flow

Design and numerical study of a bidirectional acoustic microfluidic pump enabled by microcantilever arrays

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