Query: Micropump

title: Performance of single piezoelectric vibrator micropump with check valve
abstract: A new single vibrator piezoelectric micropump which integrated the check valve and the piezoelectric oscillator is designed in this research. The micropump mainly consists of a circular piezoelectric vibrator, a polyethylene terephthalate check valve, two rubber sealing rings, upper pump cover, and lower pump cover. In this research, in order to study output performance of the single vibrator piezoelectric pump, theoretical analysis and experimental verification of the piezoelectric pump check valve have been carried out by exploiting the method of check valves and vibrator mass separation. Experimental results show that the opening of the check valve is mainly caused by the pressure difference and the inertia force. The dominant factor of check valve opening is different under different drive frequencies. A maximum opening displacement of 19.625 mm of the check valve is obtained when the micropump is driven by a sinusoidal voltage of 60 V at 300 Hz. In addition, the maximum flow rate of 2034.7 mL min 1 is obtained when the micropump is driven by a sinusoidal voltage of 60 V at 320 Hz, and a maximum output pressure of 0.82 kPa is obtained when the micropump is driven by a sinusoidal voltage of 60 V at 140 Hz.

title: Development of PZT Actuated Valveless Micropump
abstract: A piezoelectrically actuated valveless micropump has been designed and developed. The principle components of this system are piezoelectrically actuated (PZT) metal diaphragms and a complete fluid flow system. The design of this pump mainly focuses on a cross junction, which is generated by a nozzle jet attached to a pump chamber and the intersection of two inlet channels and an outlet channel respectively. During each PZT diaphragm vibration cycle, the junction connecting the inlet and outlet channels with the nozzle jet permits consistencies in fluidic momentum and resistances in order to facilitate complete fluidic path throughout the system, in the absence of any physical valves. The entire micropump structure is fabricated as a plate by plate element of polymethyl methacrylate (PMMA) sheets and sandwiched to get required fluidic network as well as the overall device. In order to identify the flow characteristics, and to validate the test results with numerical simulation data, FEM analysis using ANSYS was carried out and an eigenfrequency analysis was performed to the PZT diaphragm using COMSOL Multiphysics. In addition, the control system of the pump was designed and developed to change the applied frequency to the piezoelectric diaphragms. The experimental data revealed that the maximum flow rate is 31.15 mL/min at a frequency of 100 Hz. Our proposed design is not only for a specific application but also useful in a wide range of biomedical applications.

title: Electrostatically Driven In Plane Silicon Micropump for Modular Configuration
abstract: In this paper, an in plane reciprocating displacement micropump for liquids and gases which is actuated by a new class of electrostatic bending actuators is reported. The so called "Nano Electrostatic Drive" is capable of deflecting beyond the electrode gap distance, enabling large generated forces and deflections. Depending on the requirements of the targeted system, the micropump can be modularly designed to meet the specified differential pressures and flow rates by a serial and parallel arrangement of equally working pumping base units. Two selected, medium specific micropump test structure devices for pumping air and isopropanol were designed and investigated. An analytical approach of the driving unit is presented and two way Fluid Structure Interaction (FSI) simulations of the micropump were carried out to determine the dynamic behavior. The simulation showed that the test structure device designed for air expected to overcome a total differential pressure of 130 kPa and deliver a flow rate of 0.11 sccm at a 265 Hz driving frequency. The isopropanol design is expected to generate 210 kPa and pump 0.01 sccm at 21 Hz. The device is monolithically fabricated by CMOS compatible bulk micromachining processes under the use of standard materials only, such as crystalline silicon, silicon dioxide and alumina.

title: Integratable magnetic shape memory micropump for high pressure, precision microfluidic applications
abstract: Precisely controlling the flow of fluids on a microscopic scale has been a technological challenge in the field of microfluidics. Active microfluidics, where a defined manipulation of the working fluid is necessary, requires active components such as micropumps or microvalves. We report on an optimized design of an integratable, wireless micropump made from the magnetic shape memory (MSM) alloy Ni Mn Ga. An external magnetic field generates a shape change in the MSM material, which drives the fluid in a similar fashion as a peristaltic pump. Thus, the pump does not need electrical contacts and avoids the mechanical parts found in traditional pumping technologies, decreasing the complexity of the micropump. With a discrete pumping resolution of 50 150 nL per pumping cycle, which is further scalable, and a pumping pressure well exceeding 2 bar, the MSM micropump is capable of accurately delivering the fluids needed for microfluidic devices. The MSM micropump is self priming, pumping both liquid and gas, and demonstrates repeatable performance across a range of pumping frequencies. Furthermore, it operates simultaneously as both a valve and reversible micropump, offering superior possibilities compared to existing technologies within the flow rate range of 0 2000 uL/min. Due to its simplicity, this technology can be scaled down easily, which lends itself for future integration into lab on a chips and microreactors for life science and chemistry applications.

title: Electromagnetic actuation dual chamber bidirectional flow micropump
abstract: This paper presents the design and development of a dual chamber microchannel chip, coupled with an electromagnetic actuator for a bidirectional flow micropump system. A rapid prototyping technique is reported for the fabrication of the membrane sheet (a spin coater machine technique) microchannel chip (a photolithography technique) and controller system (a wet etching method to the circuit board) decreased development time by allowing correction and evaluation of the micropump to be made early in the process. To achieve a bidirectional flow, a dispersing depth was implemented between the microchannel chamber and inlet/outlet channel. From the numerical simulation and experimental analysis obtained, the micropump was capable for bidirectional flow application with the maximum volumetric flow rate of the fabricated micropump system at zero backpressure is 1.1254 0.0658 mLs 1 (forward direction) and 1.1266 0.0760 mLs 1 (reversed direction) The power consumption for the developed micropump system is 48.64 mW.

title: Intravitreal implantable magnetic micropump for on demand VEGFR targeted drug delivery
abstract: &NA; In this paper, we propose an intravitreal implantable magnetic micropump integrated with micro check valve capable of on demand vascular endothelial growth factor receptor (VEGFR) targeted drug delivery for the treatment of age related macular degeneration, diabetic retinopathy and other eye pathologies characterized by ocular neoangiogenesis. Precise on demand drug release is realized by the deflection of the magnetic membrane assembly according to the external magnetic field, and the membrane assembly consists of a thin elastic polydimethylsiloxane (PDMS) membrane and a cylindrical magnetic nanoparticle PDMS composite block. Additionally, a micro check valve composed of two PDMS layers was integrated into the micropump to realize a diode like one directional drug delivery and prevent undesired drug diffusion. For specifically targeting VEGFR and suppression of VEGF induced proliferation of microvascular endothelial cells, anti Flt1 gold nanocomplexes are synthesized. In vitro and in vivo experiments and quantitative analysis are carried out in order to verify our proposed concept: precise drug release control according to the external magnetic field, targeting to microvascular endothelial cells, and efficient and on demand drug delivery from the proposed micropump to the macular area of rabbit's eye.

title: A hydrostatic pressure driven passive micropump enhanced with siphon based autofill function.
abstract: Autonomous and self powered micropumps are in critical demand for versatile cell and tissue based applications as well as for low cost point of care testing (POCT) in microfluidics fields. The hydrostatic pressure driven passive micropumps are simple and widely used, but they cannot maintain steady and continuous flow for long periods of time. Here, we propose a hydrostatic pressure driven passive micropump enhanced with siphon based autofill function, which can realize the autonomous and continuous perfusion with well controlled steady flow over an extended time without electric power consumption. The characterization results reveal that both the cycle number in one refilling loop and the siphon diameter will affect the refilling time. Furthermore, this micropump also enables multiplexed medium delivery under either the same or different flow conditions with high flexibility. The system was validated using an in vitro vasculogenesis model over the course of several days. Most importantly, the device can consistently provide steady medium perfusion for up to 5 days at a predefined hydrostatic pressure drop without the need for supplemental medium changes. We believe that this hydrostatic pressure driven passive micropump will become a critical module for a broad range of sophisticated microfluidic operations and applications.

title: Optimization of Micropump Performance Utilizing a Single Membrane with an Active Check Valve
abstract: In this study, we successfully designed and tested a new micropump that utilizes an active check valve and bottom protruding structure to achieve sample transportation. We performed theoretical analyses and numerical simulations to determine the optimal location of the active check valve. We also experimentally analyzed variations in the generated flow rate with respect to the pneumatic frequencies, actuated air pressures, and locations of the active check valve. The experimental results indicate the optimum air pressure, driving frequency, and location of the active check valve to be 68.9 kPa, 26.0 Hz, and 2.0 mm, respectively. We obtained a maximum pumping rate of 488 mL/min and a maximum pumping efficiency of 35.4% The proposed micropump could perform a crucial function in the transportation of microfluids and could be incorporated into micro total analysis systems.

title: A novel valveless piezoelectric micropump with a bluff body based on Coanda effect
abstract: Based on the Coanda effect, a novel valveless micropump is presented in this paper, the special bluff body is utilized to enhance the Coanda effect and increase the net flow of the micropump. In order to reveal the influence of structural parameters on the performance of novel micropump, five micropump samples with different chamber radii (5 mm and 9 mm) aspect ratios (4 and 8) and channel angles (30deg and 45deg) are fabricated by silicon based MEMS technology. On the conditions of the voltages (50 300 vpp) and excitation frequencies (25 125 Hz) the performance of the micropumps is studied experimentally in detail. As the voltage V 300 vpp and the frequency f 50 Hz, the maximum net flow and back pressure for the optimal sample can attain 4.84 ml/min and 1.75 kPa, respectively. Through numerical simulations, the efficiency of the micropumps with different aspect ratios L1/d (3 9) are investigated as Reynolds number range from 300 to 1000 at the frequencies of 5 400 Hz. When the Reynolds number is constant, the pump efficiency has the optimal value with the increase of frequency, and the streamline diagrams indicate that this is related to the effects of the internal vortexes.

title: Light powered direction controlled micropump
abstract: A micropump induces the flow of its surrounding fluids and is extremely promising in a variety of applications such as chemical sensing or mass transportation. However, it is still challenging to manipulate its pumping direction. In this study, we examine a binary micropump based on perovskite and poly[(2 methoxy 5 ethylhexyloxy) 1,4 phenylenevinylene] (MEHPPV) The micropump is operational under the influence of light. Light exhibits significant versatility in controlling the pumping phenomenon of the micropump. It governs the start and stop and also regulates the velocity and directions. The direction control signifies immense opportunities for the development of micropumps with unprecedented pumping behaviors and functions (such as heartbeat like pumping, rectification, and amplification) This makes them potentially useful in various fields. Hence, it is expected that the micropump reported in the current study could act as a key step towards the further development of more sophisticated micropumps for diverse applications.