Electromagnetic Micropump Research Articles

A peristaltic electromagnetic (EM) micropump with dome-shaped PDMS membranes for biomedical application

A peristaltic electromagnetic (EM) micropump driven by dome-shaped membranes was successfully fabricated and tested. The pump system comprises EM coil components, three magneto-mechanical actuators, and a microfluidic system. The pump system with three actuator membranes/chambers connected in series is intended to replace the conventional valve and pump rollers, enabling the delivery of fluids at a high flowrate. The actuator membrane is made of polydimethylsiloxane (PDMS), measuring 5 mm in diameter and approximately 100 µm thick, and fabricated using soft lithography techniques to form a normally deflected dome-shaped membrane structure. The microfluidic channel is made of PDMS and created using a sacrificial layer-pattern process, allowing straightforward soft-litography process without mold transfer. The fabricated device was tested by applying electrical DC currents ranging from 500 mA to 1000 mA at frequencies up to 10 Hz. This resulted in the depletion of the membrane by up to 2 mm, causing fluid flow through the microchannel at a flow rate of 8 mL per minute. The test results revealed that the peristaltic EM micropump can generate a significant fluid flow rate, making it suitable for pumping controlled fluids within a range of up to 10 mL/minute. This micropump has a wide range of potential applications, including the management of insulin medication for patients with acute diabetes mellitus and the delivery of drugs and dialysate fluid in artificial kidney applications.

Ultra-low-energy operation of electromagnetic bi-stable actuator under restricted energy supply

During the periodic drug administration for chronic diseases, unexpected battery depletion can be significantly problematic for the patients. While body heat harvesting utilizing the wearable thermoelectric generator (WTEG) shows the significant potential in continuous drug delivery systems (DDSs) by providing ceaseless power source, the power and the voltage output might not be sufficient to drive micropump actuators in such drug delivery systems. The continuous actuating current also imposes an additional challenge in developing efficient and compact voltage boosting circuits. In this paper, we propose an ultra-low-energy operating method of the WTEG-powered electromagnetic micropump system. In combination with our electromagnetic bi-stable actuator (EBA) where the energy demand is discretized, we present (1) the dedicated high-efficient charge pumps (CPs) (2) and the actuating pulse control method to prevent redundant energy waste. The proposed 10-stage charge pump is designed to reduce the conversion loss by utilizing multiple flying-capacitor switching structure, and the 2-stage series–parallel charge pump (SPCP) is fabricated with flexible thin-film super-capacitors (TFSCs) to realize the high boosting performance within compact and wearable features. Applying the proposed control method with the 10-stage CP in our WTEG-powered micropump system, we significantly reduce the charging time per actuation by 88.8% compared to the commercial boosting circuit. Also, the 2-stage SPCP achieves 84.0% reduction in the charging time while utilizing flexible and wearable features, showing a significant potential for self-powered wearable healthcare applications.

Impact of the Stefan gusting on a bioconvective nanofluid with the various slips over a rotating disc and a substance-responsive species

This paper presents thorough computational and theoretical analyses of steady forced convective flow over a rotating disc submerged in a water-based nanofluid containing microorganisms. It delves into the examination of boundary layer flow characteristics of a viscous nanofluid, considering Stefan blowing effects and multiple slip conditions influenced by a magnetic field. Notably, the study accounts for novel aspects such as thermal radiation and both constructive and destructive chemical reactions. The movement of nanoparticles is elucidated based on thermophoresis and microscopic behaviors, while changes in volume fraction do not affect the thermo-physical properties of the nanofluid. To address the altered nonlinear set of differential equations, an effective numerical approach, the Keller-Box method, is implemented for critical and efficient solutions. These appropriate transformations are defined and applied. When compared to blowing suction, it shows a better enhancement in the rate of heat transfer, mass, and microorganisms. Some of the main observations are there is a decrease in wall skin friction in the directions of radial and tangential as magnetic field strength is increased. The evaluation of thermal boundary layer thickness and temperature is noted for the radiation parameter (Rd) improvement. The present analysis has applications in electromagnetic micro-pumps and nanomechanics. As to the applications in the science and engineering fields, technologies such as micro-electromechanical systems-based microfluidic devices and microfluidic-related technologies will be accepted.

High performance electromagnetic micropump with bio-inspired synchronous valves for integrated microfluidics

High performance electromagnetic micropump with bio-inspired synchronous valves for integrated microfluidics

Fabrication of peristaltic electromagnetic micropumps using the SLA 3D printing method from a novel magnetic nano-composite material

Micropumps are one of the main components of microfluidic systems that play an essential role in the development of these systems. They are responsible for the fluid movement inside the microfluidic systems. In this paper, three electromagnetic micropumps with single, double, and triple chambers fabricated using the stereolithography (SLA) 3D printing method from a novel UV-curable magnetic nanocomposite material are presented. The components of this micropump include nozzle-diffuser microchannels, a chamber, a flexible magnetic membrane, and a micro-coil. To determine the characteristics of the proposed micropumps, the effect of the electric current signal and its patterns and magnetic field strength on the temperature changes, magnetic nanoparticle concentration on the membrane displacement, and flow rate of the micropump have been investigated. The micropump membrane with 5 wt% nanoparticles concentration can achieve a displacement of 65 µm for an electric current of 1000 mA in 12 s. The highest fluid flow rate of single, double, and triple chamber micropumps are 78, 316, and 600 nL/s, respectively, at an electric signal with a period of 8 s and a duty cycle of 60%.

A novel electromagnetic micropump with PDMS membrane supported by a stainless-steel microstructure

As a main component, membrane micropumps play a key role in developing microfluidic systems. This part pumps fluids by deflecting a membrane using a micro-actuator with a deflection range of a few micrometers during a few seconds. Most electromagnetic micropumps have low lifetime and fracture toughness or low recovery speed. Micropumps with metallic mass-spring structures can overcome the mentioned disadvantages or limitations. This study investigated the fabrication and characterization of a novel electromagnetic micropump. The proposed micropump consists of a stainless-steel mass-spring structure, a polydimethylsiloxane body and membrane, a permanent NdFeB magnet, a micro-coil, and a 3D printed spacer. To characterize the micropump, the effects of the frequency and duty cycle of the electric current applied to the micro-coil on the micropump flow rate and the membrane deflection vs. time were investigated. A membrane deflection of ±8 µm was obtained in 4 s by applying 1000 mA electrical current to the micro-coil. The maximum volumetric flow rate of 523 nl s−1 was obtained at a frequency of 125 mHz and a duty cycle of 50%. The von Mises stress distribution in the micropump membrane and variations of the fluid velocity in the microchannels were analyzed using the finite element method.

Design and research of the one-way microsphere valve and the PDMS film electromagnetic micropump

Design and research of the one-way microsphere valve and the PDMS film electromagnetic micropump

High efficiency 3D printed electromagnetic micropump with a synchronous active valve

This work describes the design and characterization of a novel electromagnetically actuated 3D printed micropump that efficiently employs a synchronized active valve to achieve a high flow rate. The micropump utilizes two elastic membranes attached to magnets in two chambers for the pump and the valve, and a modular design is employed to allow for easy assembly and attachment to a microfluidic chip. The micropump's entire housing is 3D printed by fused deposition modeling to allow for ease of fabrication and flexible adoption to microfluidic applications. The proposed system can produce a flow rate of 6.1 ml/min at 5 V and a power consumption of 0.5 W – the highest reported value for flow rate at such a power consumption and electromagnetic pump size. The system can achieve a maximum specific flow rate and backpressure of 11.89 ml/min.W and 693 Pa/W, respectively. A novel idea of incorporating two Hall effect sensors into the pump and valve chambers allowed optimization of the pump's operating parameters and synchronization of the pump's stroke relative to the valve opening onset, which led to minimal throttling and friction losses. Moreover, the pump's unique design efficiently allowed the powerful magnets and coils to be integrated within a total occupied volume of 20 × 30 × 10.5 mm3. The micropump's performance is assessed over a range of operating frequencies, and the pump's functionality is evaluated by utilizing it to circulate fluid in a microfluidic chip, demonstrating its suitability for lab/body-on-chip applications.

Ascendancy of electromagnetic force and Hall currents on blood flow carrying Cu-Au NPs in a non-uniform endoscopic annulus having wall slip

This article aims to outline the characteristics of the blood flow conveying copper (Cu) and gold (Au) nanoparticles (NPs) through a non-uniform endoscopic annulus with wall slip under the action of electromagnetic force and Hall currents. The flow of blood with the suspension of hybrid nanoparticles in the annulus is induced by the peristaltic pumping. The governing equations are modeled and then simplified with the postulate of lubrication theory. The resulting non-dimensional momentum equation after simplification is solved analytically by employing the He's homotopy perturbation method (HPM) with the computational software Mathematica program (version 11). The influential role of emerging physical parameters on the physiological features related to the blood flow is inferred graphically and physically. The analytical outcomes reveal that Hall parameter has a diminishing behavior on the blood flow while the inverse impact is endured for mounting Hartmann number. Electromagnetic field and Hall currents offer a superlative mode for regulating blood flow at the time of surgery. An increment in the volume fraction of nanoparticles causes a drop in the blood temperature profile. The trapping phenomenon is also explored with the help of contours. An expansion in Hartmann number reduces the size of entrapped bolus and ultimately vanishes when Hartmann number is very large. This prospective model may be applicable in electromagnetic micro-pumps, medical simulation devices, heart-lung machine (HLM), drug carrying and drug transport systems, cancer diagnosis, tumor selective photothermal therapy, etc.

Metallic glass thin film integrated with flexible membrane for electromagnetic micropump application

In this work, metallic glass (MG) thin film integrated with flexible membrane for use in an electromagnetic micropump was proposed and developed. Fe-based MG thin film deposited on a flexible membrane was employed as the actuation membrane. The electromagnetic force generated between the electromagnetic coil and the magnetized thin film was used to excite the actuation membrane. The actuation membrane was integrated with a microchannel for the micropump application. The fluid in the microchannel was driven by the pressure change resulting from the membrane deflection. Membrane deflection of 45 μm was achieved when a current of 0.12 A was applied to the electromagnetic coil. In addition, a maximum flow rate of 0.17 μl min−1 was achieved and driven by the electromagnetic micropump. The Fe-based MG integrated with the flexible membrane actuated by electromagnetic force could be applied to the actuation membrane for the electromagnetic micropump.

Manipulate microfluid with an integrated butterfly valve for micropump application

This paper reports a novel electromagnetic micropump (EMP) that only uses one vibrating integrated butterfly valve (IBV) to manipulate microfluid directly. The IBV, composed of a Polyimide (PI) slice, a moving magnet and elastic silica gel diaphragm, could open or close periodically stimulated by external alternating magnetic field. The micropump is instantaneous fluid pressure-dependent for simple structure by integrating the butterfly valve and moving parts into one valve. In the suction mode, the positive instantaneous pressure pushes the valve, driving the fluid crossing the valve. While in the expelling mode, the negative instantaneous pressure compresses the slice and closes the valve, pushing fluid out. The test results not only show a frequency-dependent flow rate relationship and determine a resonance frequency of 15 Hz, but also give linear curves between flow rate/backpressure and applied current. Furthermore, the designed micropump exhibits a maximum flow rate and backpressure of 9.47 mL/min and 70.5 mmH2O respectively. For its simplicity, this novel micropump technology could be scaled down easily, which could be further integrated and applied in a microsystem.

A Minimized Valveless Electromagnetic Micropump for Microfluidic Actuation on Organ Chips

In recent years, organ chips have become an ideal alternative for physiological and pathological studies as well as drug screening. To more realistically simulate the in vivo physiological environment, micropumps are often needed as power sources to achieve dynamic culture in organ chips. In this study, we present a valveless electromagnetic micropump that can be used in organ chips. Fluid flow is actuated by the vibration of a PDMS membrane through a varying magnetic field. This micropump uses a nozzle/diffuser structure instead of valves, which simplifies the structure. By reducing the volume of the coil and magnet, the size of the electromagnetic micropump is minimized so that it can be integrated on a microfluidic chip. The micropump and the chip can be portably packaged by using a small signal generation module and a dry battery to supply the coil with a square wave, reducing the dependence on external devices. In addition, multiple electromagnetic micropumps can be integrated on a single chip. These micropumps can be connected in series or in parallel, which can achieve complicated flow conditions and can simulate physiological fluid flow more realistically in different types of organ chips. The flow rate was measured to characterize the actuating performance of the micropump. We established the dynamic coculture of a liver and breast cancer model on the chip, with medium actuated by the electromagnetic micropump. Cell viability, albumin and IL-6 were analyzed. The results indicated that dynamic coculture, which was actuated by the electromagnetic micropump, was beneficial for cell growth and function compared with the static control group.

Unidirectional and bidirectional valveless electromagnetic micropump with PDMS-Fe3O4 nanocomposite magnetic membrane

In this paper, a nozzle-diffuser electromagnetic micropump with nanocomposite magnetic membrane for sub-microliter pumping applications is presented. The membrane included magnetite (Fe3O4) nanoparticles dispersed in a layer of polydimethylsiloxane (PDMS). Fe3O4 as a nontoxic and environmentally friendly material with excellent magnetic properties is used for the first time in the fabrication of an electromagnetic micropump. In order to achieve the most biocompatibility, PDMS is applied in most parts of the micropump. Lack of control on the recovery time of the membrane is one of the most important disadvantages of the proposed micropumps in the literature. This weakness causes an imbalance between the supply and pump mode of the micropumps leading to an undesirable performance of both of these. To address this issue, a bidirectional electromagnetic micropump is presented in this paper. In this system a secondary magnetic field is applied to equalize the response and recovery time of the membrane. Using this novel micropump, the maximum flow rate of 1.25 µl min−1 at the frequency of 0.1 Hz has been achieved. To indicate the best performance conditions for the micropump, effective parameters on the micropump performance were examined. These parameters include the size of the microchannels, electric current, number of coil turns, concentration of the Fe3O4 nanoparticles and frequency.

Design and experimental investigation of a bi-directional valveless electromagnetic micro-pump

In this paper, a design of a novel electromagnetic micro-actuator prototype is presented. This prototype is fabricated using conventional elements for a novel working principle as bi-directional valveless micro-pump for biomedical applications. The proposed micro-pump includes two unfixed permanent magnets placed in opposite polarities in a cylindrical channel. The channel is placed between two fixed coaxial coils as external electromagnets. The electromagnetic actuating depends on moving both unfixed permanent magnets vertically via the interaction of their magnetic fields and that resulting from coils. The actuation of magnets is produced with a periodic movement and consists mainly of three main modes. By selecting a suitable coil’s driving currents, the actuation can be controlled either to change fluid flow direction or the actuation speed. An experimental test shows the high performance of the proposed micro-pump, a flow rate of 37 ml/mn and maximum back pressure of 1.98 kPa are attained.

The Design, Fabrication, and Testing of an Electromagnetic Micropump with a Matrix-Patterned Magnetic Polymer Composite Actuator Membrane.

A valveless electromagnetic (EM) micropump with a matrix-patterned magnetic polymer composite actuator membrane structure was successfully designed and fabricated. The composite membrane structure is made of polydemethylsiloxane (PDMS) that is mixed with magnetic particles and patterned in matrix blocks. The matrix magnetic composite membrane was fabricated using a soft lithography process and expected to have a compact structure having sufficient magnetic force for membrane deformation and maintained membrane flexibility. The magnetic membrane was integrated with the microfluidic system and functionally tested. The experimental results show that a magnetic composite actuator membrane containing of 6% NdFeB is capable of producing a maximum membrane deflection up to 12.87 µm. The functionality test of the EM actuator for fluid pumping resulted in an extremely low sample injection flow rate of approximately 6.523 nL/min. It was also concluded that there is a correlation between the matrix structure of the actuator membrane and the fluid pumping flow rate. The injection flow rate of the EM micropump can be controlled by adjusting the input power supplied to the EM coil, and this is believed to improve the injection accuracy of the drug dosage and have potential in improving the proficiency of the existing drug delivery system.

Study of valveless electromagnetic micropump by volume-of-fluid and OpenFOAM

The paper reports the first study on the backpressure of a valveless electromagnetic micropump using the volume-of-fluid (VOF) technique and open-source code OpenFOAM. The micropump consists of a vibrating diaphragm and fluidic microchannel connected to inlet and outlet tubes. The imbalance in fluid resistance of the fluidic microchannel during a vibration cycle of the diaphragm creates backpressure in the pump, which in turn produces a difference in water level between the inlet and outlet tubes. In this study, VOF was used in a transient simulation to obtain this difference in water level and then the backpressure. The obtained backpressure showed a slight discrepancy with the experimental data. The discrepancy was probably due to the difference in the wall surface quality of the fluidic microchannel between the simulation model and experimental device. These results are useful for analytical and numerical research on these types of micropumps and can easily be applied in an open-source code simulator with almost zero cost.

Development of an electromagnetic micropump with photosensitive magnetic nanocomposite

Development of an electromagnetic micropump with photosensitive magnetic nanocomposite

A dynamic model for studying valveless electromagnetic micropumps

In this paper, a fluid–diaphragm coupling model is proposed for studying the dynamic performance of a valveless micropump. In the model, fluid inertia is included and fluid pressure is obtained by solving the coupling equation simultaneously with Navier–Stokes equations through a transient dynamic mesh simulation. This process avoids the omission of the phase shift between the pressure force on the diaphragm and the flow rate of the pump. Furthermore, in this model, empirical parameters are almost eliminated. The model was applied to study the dynamic performance of a valveless electromagnetic micropump which uses a new working principle. The obtained results show that the flow rate attains its maximum value for a range of driving frequency. For instance, the flow rate reaches 1.6 ml min−1 for frequencies of 26–30 Hz when the electromagnetic force is 20 mN. The simulation results demonstrate that the flow rate of the proposed pump is much larger than that of the diffuser pump counterpart. A MEMS prototype has been fabricated and the attained backpressure validates the new pumping principle of the pump.

Design and fabrication of microfluidic actuators towards microanalysis systems for bioaffinity assays

This work focuses on the realization of three different micro-actuators that will be integrated in a lab-on-chip for bioaffinity assays. The aim is to create a microfluidic network to control the sample and reagent delivery as well as the washing cycles for a complete analysis. The three micropumps have different working principles (electromagnetic, electrolytic and peristaltic actuation methods), but they share the same fabrication process. The reason for adopting three different actuation modes is mainly related to the different functionalities that have to be managed at microfluidic level. In particular the electrolytic one-shot micropump will be used for sample and reagents delivery, while the peristaltic and the electromagnetic micropumps are both good candidates for the washing cycles.

Principle design and actuation of a dual chamber electromagnetic micropump with coaxial cantilever valves

This paper deals with the design and characterization of an electromagnetic actuation micropump with superimposed dual chambers. An integral part of microfluidic system includes micropumps which have become a critical design focus and have the potential to alter treatment and drug delivery requirements to patients. In this paper, conceptual design of variable geometrical nozzle/diffuser elements, coaxial cantilever valve, is proposed. It takes advantages of cantilever fluctuating valves with preset geometry to optimize and control fluid flow. The integration of this conceptual valve into a dual chamber micropump has increased the flow rate when compared to a single chamber micropump. This technique also allows for the fluid flow to be actively controlled by adjusting the movement of the intermediate membrane and the cantilever valves due to their fast response and large deflection properties when subjected to an electromagnetic field. To ensure reliability and performance of both the membrane and electromagnets, finite element method was used to perform the stress-strain analysis and optimize the membrane structure and electromagnet configuration. The frequency-dependent flow rates and backpressure are investigated for different frequencies by varying the applied currents from 1A to 1.75A. The current micropump design exhibits a backpressure of 58 mmH(2)O and has a water flow rate that reaches maximum at 1.985 ml/s under a 1.75A current with a resonance frequency of 45 Hz. This proposed micropump while at its initial prototype stage can satisfy the requirements of wide flow rate drug delivery applications. Its controllability and process design are attractive for high volume fabrication and low cost.