scholarly journals Design and Characterization of a Magnetically Driven Valveless Micropump for Drug Delivery

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
Y. Zhou ◽  
F. Amirouche ◽  
L. Chen
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Resonant Frequency ◽  
Flow Rate ◽  
Excitation Frequency ◽  
Maximum Flow ◽  
Dual Chamber ◽  
Pumping Rate ◽  
Valveless Micropump ◽  
Magnetic Forces

Micropump, an actuation source to transfer the fluid from reservoir to the target place with accuracy and reliability, plays an important role in microfluidic devices. A broad range of micropump applications in biomedical fields are found in the fluid fine regulation and precise control systems for implantable drug delivery, chemical and biological detection, as well as blood transport in cardiology system. A polydimethylsiloxane (PDMS) magnetic composite membrane based on microfabrication with dimensions of 6 mm and 65 μm in diameter and thickness respectively, is employed to actuate a proposed micropump. In micro pumping operation, the fluid flow effects on the actuation and dynamic response of an oscillating membrane are curial to the design of the micropump. Therefore, the resonant frequency of this micro device is estimated considering the added mass and fluid damping to understand the behaviors of the valveless micropump. In this study, the membrane actuation is implemented by a miniaturized electromagnet, which provides an external time-varying magnetic field. The magnetic force on the membrane is proportional to the gradient of the magnetic field and the magnetization of the micro particles embedded in the membrane. The alternating attractive and repulsive magnetic forces on this composite membrane are computed by Finite Element Analysis (FEA). The basic design issues of the electromagnetic actuator involving air gaps, input current signals, and distribution of magnetic flux in the magnetic circuit are presented. Moreover, the magnetic-structure coupling analysis is conducted to determine the maximum deformation and stresses on the membrane, which result from the action of these magnetic forces. Finally, frequency-dependent flow rate of a dual-chamber configuration micropump has been studied. The pumping rate increases almost linearly with the excitation frequency at low ranges and there exists resonant frequencies at which the flow rate will reach a maximum value. After the flow rate peaks, the pumping rate decreases sharply along with the actuating frequencies. The maximum flow rate for the dual-chamber remains at 27.73μl/min under 0.4 A input current with an excitation frequency of 3 Hz. For comparison, a single-chamber micropump reaches a maximum flow rate of 19.61μl/min with a resonant frequency of 4.36 Hz under the same condition.

Piezo-Actuated Valveless Micropumps for Micro-Total Analysis Systems

2010 ◽  
Author(s):  
Arvind Chandrasekaran ◽  
Muthukumaran Packirisamy
Keyword(s):  
Flow Rate ◽  
Glass Substrate ◽  
Flow Characteristics ◽  
Low Frequency ◽  
Lab On A Chip ◽  
Maximum Flow ◽  
Valveless Micropump ◽  
Chip Flow ◽  
Micro Total Analysis Systems ◽  
Total Analysis

In this work, a Piezo actuated Valveless micropump is proposed for applications in Micro-Total Analysis Systems (μTAS) and Lab-on-a-Chip. Flow rectification in the micropump has been brought about with the use of a diffuser element. The device is fabricated on PDMS-Glass substrate with the glass acting as the diaphragm. A PZT disc is integrated with the setup for actuation. The micropump has been characterized for its dynamic behavior, flow characteristics, and pressure. It was found that the maximum flow rate for the micropump was obtained at low frequency which makes it usable for practical μTAS applications.

Development of FGM Monomorph Actuator for Impedance Pump Application

2007 ◽  
Vol 334-335 ◽  
pp. 1077-1080 ◽  
Author(s):  
Yan Hong Chen ◽  
Tao Li ◽  
Jan Ma ◽  
F.Y.C. Boey
Keyword(s):  
Resonant Frequency ◽  
Piezoelectric Property ◽  
Flow Rate ◽  
Electrophoretic Deposition ◽  
Maximum Flow ◽  
Full Density ◽  
Layer By Layer ◽  
Sequential Deposition ◽  
Impedance Pump

In the present work, the FGM monomorph actuator was developed and applied in the impedance pump. The actuator was fabricated using electrophoretic deposition (EPD). Two starting materials, pure PZT and doped PZT, were mixed to form four different compositions. The actuator was then fabricated by sequential deposition of the four compositions layer by layer on the substrate and followed by sintering to full density. The actuator shows both piezoelectric property and microstructural gradient across the layers. The actuator is able to achieve a bending displacement of nearly 2 mm at resonant frequency. It has been successfully applied to the impedance pump as the actuating component. The pumping action comes from the periodic compression by the actuator to induce a net flow. Maximum flow was observed at the resonant frequency of the actuator. A flow rate of about 9 ml/min was generated.

A PZT Micropump With Planar Passive Valves and its Flow Measurements

2009 ◽  
Author(s):  
Chia-Jui Hsu ◽  
Horn-Jiunn Sheen
Keyword(s):  
Flow Rate ◽  
Excitation Frequency ◽  
Maximum Flow ◽  
Driving Frequency ◽  
Flow Measurements ◽  
Piv Measurements ◽  
Optimum Flow Rate ◽  
Micro Piv ◽  
Valve Motion ◽  
Pumping Efficiency

In this paper, a simply-designed reciprocating-type micropump is presented. We also report the coupling effects between the valve motion and the flow behaviors, which were studied using a micro-PIV technique. The fluids were easily driven by a PZT plate and net flow was directed toward the outlet after rectification by two planar passive valves. The results revealed that good pumping performance was obtained even at a low excitation voltage of 10V. The optimum flow rate was measured at a frequency of 0.8kHz and the maximum flow rate was 275μl/min at 30V. The micropump was uniquely characterized by the existence of a linear relationship between the flow rate and the driving frequency, which enabled this micropump to be easily operated and controlled. The experimental results showed that the micropump was reliable in terms of the high linearity and repeatability, which is very favorable for portable microfluidic systems. The micro-PIV measurements of the transient motions of the valve and the flow behaviors clearly revealed that the valve efficiency depended on the mass inertia of the moving part, excitation frequency, and voltage. The present results are useful for the optimum design of this planar passive valve to improve the pumping efficiency.

scholarly journals Development and Application of One-Sided Piezoelectric Actuating Micropump

2013 ◽  
Vol 2013 ◽  
pp. 1-16
Author(s):  
H. K. Ma ◽  
Y. T. Li ◽  
H. C. Su ◽  
W. F. Luo ◽  
T. J. Pan ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Maximum Flow ◽  
Cell System ◽  
Valveless Micropump ◽  
The Third ◽  
Air Inlet ◽  
Frequency Modulator ◽  
Microfuel Cell ◽  
Secondary Chamber

Three types of one-sided actuating piezoelectric micropumps are studied in this paper. In the first type, one-sided actuating micropump with two check valves can enhance the flow rate and prevent the back flow in suction mode to keep the flow in one direction. Furthermore, the frequency modulator is applied in the micropump to adjust and promote the maximum flow rate higher than 5.0 mL/s. In the second type, valveless micropump with secondary chamber shows that the secondary chamber plays a key role in the application of the valveless micropump. It not only keeps the flow in one direction but also makes the flow rate of the pump reach 0.989 mL/s. In addition, when a nozzle/diffuser element is used in valveless micropump, the flow rate can be further improved to 1.183 mL/s at a frequency of 150 Hz. In the third type, piezoelectric actuating pump is regarded as an air pump in the application of a microfuel cell system, which can increase more air inlet to improve the fuel/air reaction and further increase the performance of fuel cell.

EXPERIMENTAL STUDY ON BASIC PERFORMANCE OF ELECTROOSMOTIC PUMP WITH ION EXCHANGING POROUS GLASS SLIT

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2627-2632 ◽  
Author(s):  
HO LEE ◽  
GYU MAN KIM ◽  
CHOON YOUNG LEE ◽  
CHEOL WOO PARK ◽  
DAE JOONG KIM
Keyword(s):  
Drug Delivery ◽  
Experimental Study ◽  
Flow Rate ◽  
Maximum Flow ◽  
Precise Control ◽  
Electroosmotic Pump ◽  
Optimal Drug ◽  
Basic Performance ◽  
Electroosmotic Pumping ◽  
Performance Results

The basic concept and preliminary performance results of a miniaturized electroosmotic pump with diaphragms were included in the present study. The separation of an electroosmotic pumping liquid from a drug using diaphragms is mainly to have a freedom in choosing an electroosmotic pumping liquid and to achieve the optimal drug delivery with its preferable precise control. As a result, the maximum flow rate and current increased linearly according to the increment of applied voltage that is electric potential.

Valveless Micropump with Saw-Tooth Microchannel

2014 ◽  
Vol 613 ◽  
pp. 228-235 ◽  
Author(s):  
Ying Hua Xu ◽  
Wei Ping Yan ◽  
Li Guo
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Width Ratio ◽  
Driving Voltage ◽  
Tooth Structure ◽  
Valveless Micropump ◽  
Micro Pump ◽  
Pump Flow Rate ◽  
Mems Technology ◽  
Micro Total Analysis Systems

The micropump is the executive component in a microfluidic chip which impels the sample to flow. Its performance directly affects the precision and reliability of Micro Total Analysis Systems (μTAS), and it also plays a key role in the targeting transport of trace substances. The single and double chamber valveless micropumps with saw-tooth microchannel were designed. The saw-tooth diffuser/nozzle pipe was fabricated on chrome glass substrate using MEMS technology and the pump diaphragm was manufactured by PMMA material. The piezoelectric bimorph with cantilever beam was adopted as driving pump actuator and PDMS material as pump diaphragm. The valveless micropumps for both single and double chambers were formed with different saw-tooth structure parameters. The flow rate increased about 25% when the sidewall of microchannel changed from smooth to saw-tooth, and with the driving voltage increasing, the positive and negative flow difference of saw-tooth diffuser/nozzle pipe increased significantly, so does the micro pump flow rate. The best diffused angle θ was determined by the microchannel length L of saw-tooth diffuser/nozzle pipe, and the micro pump operated with its maximum flow rate only when the length-width ratio A reached the best value. The flow rate of a saw-tooth diffuser/nozzle valveless micropump with parallel double chambers increased approximately 30% than that of a single chamber.

Regulating Motion of Magnetic Capsules in Microfluidic Systems

2010 ◽  
Author(s):  
Hassan Masoud ◽  
Alexander Kilimnik ◽  
Alexander Alexeev
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Targeted Drug Delivery ◽  
Biomedical Applications ◽  
Drug Delivery Systems ◽  
Viscous Fluids ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Forces ◽  
Targeted Drug ◽  
Targeted Drug Delivery Systems

Magnetic microcapsules are often used as vesicles in targeted drug delivery systems, where focused magnetic field propels the capsules to highly specific locations in tissue. To fully realize this potential it is important to understand the dynamics of magnetically-responsive micrometer sized particles in viscous fluids and the effect of boundaries on particle motion. Furthermore, for practical biomedical applications, it could be useful to create synthetic micrometer-sized vesicles able to perform controlled self-propelled motion. Herein, using computer simulations, we examine the motion of magnetically-responsive synthetic microcapsules that able to crawl along walls in microchannels filled with a viscous fluid. The compliant fluid-filled capsules considered in this study encompass superparamagnetic nanoparticles in their solid shells and, therefore, can be manipulated by alternating magnetic forces.

Outcome of Buccal Mucosal Graft Urethroplasty in Long Segment Anterior Urethral Stricture

2020 ◽  
Vol 19 (2) ◽  
pp. 64-68
Author(s):  
Mrinmoy Biswas ◽  
Sudip Das Gupta ◽  
Mohammed Mizanur Rahman ◽  
Sharif Mohammad Wasimuddin
Keyword(s):  
Urethral Stricture ◽  
Flow Rate ◽  
Surgical Outcome ◽  
Simple Technique ◽  
Anterior Segment ◽  
Maximum Flow ◽  
Anastomotic Site ◽  
Buccal Mucosal Graft ◽  
Male Patients

Objective: To assess the success of BMG urethroplasty in long segment anterior urethral stricture. Method: From January 2014 to December 2015, twenty male patients with long anterior segment urethral stricture were managed by BMG urethroplasty. After voiding trial they were followed up at 3 month with Uroflowmetry, RGU & MCU and PVR measurement by USG. Patients were further followed up with Uroflowmetry and PVR at 6 months interval.Successful outcome was defined as normal voiding with a maximum flow rate >15ml /sec and PVR<50 ml with consideration of maximum one attempt of OIU after catheter removal. Results: Mean stricture length was 5.2 cm (range 3-9 cm) and mean follow-up was 15.55 months (range 6-23 months). Only two patients developed stricture at proximal anastomotic site during follow-up. One of them voided normally after single attempt of OIU. Other one required second attempt of OIU and was considered as failure (5%). Conclusion: BMG urethroplasty is a simple technique with good surgical outcome. Bangladesh Journal of Urology, Vol. 19, No. 2, July 2016 p.64-68

scholarly journals Studies about the design of magnetic bionanocomposite

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Müller ◽  
Janna Kuchinka ◽  
Thomas Heinze
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Mössbauer Spectroscopy ◽  
Fatty Acid ◽  
Optical Microscopy ◽  
High Frequency ◽  
Mossbauer Spectroscopy ◽  
Fatty Acid Esters ◽  
Iron Oxide Particles ◽  
Mößbauer Spectroscopy

Abstract Magnetic nanocomposites are a class of smart materials that have attracted recent interest as drug delivery systems or as medical implants. A new approach toward the biocompatible nanocomposites suitable for remote melting is presented. It is shown that magnetite nanoparticles (MNPs) can be embedded into a matrix of biocompatible thermoplastic dextran esters. For that purpose, fatty acid esters of dextran with adjustable melting points in the range of 30–140 °C were synthesized. Esterification of the polysaccharide by activation of the acid as iminium chlorides guaranteed mild reaction conditions leading to high-quality products as confirmed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy as well as by gel permeation chromatography (GPC). A method for the preparation of magnetically responsive bionanocomposites (BNCs) was developed consisting of combined dissolution/suspension of the dextran ester and hydrophobized MNPs in an organic solvent followed by homogenization with ultrasonication, casting of the solution, drying and melting of the composite for a defined shaping. This process leads to a uniform distribution of MNPs in BNC as revealed by scanning electron microscope (SEM). Samples of different geometries were exposed to high-frequency alternating magnetic field (AMF). It could be shown that defined remote melting of such biocompatible nanocomposites is possible for the first time. This may lead to a new class of magnetic remote-control systems, which are suitable for controlled release applications or self-healing materials. BNCs containing biocompatible dextran fatty acid ester melting close to human body temperature were prepared and loaded with Rhodamine B (RhB) or green fluorescent protein (GFP) as model drugs to evaluate their potential use as drug delivery system. The release of the model drugs from the magnetic BNC investigated under the influence of a high-frequency AMF (20 kA/m at 400 kHz) showed that on-demand release is realized by applying the external AMF. The BNC possessed a long-term stability (28 d) of the incorporated iron oxide particles after incubation in artificial body fluids. Temperature-dependent mobility investigations of MNP in the molten BNC were carried out by optical microscopy, magnetometry, alternating current (AC) susceptibility, and Mössbauer spectroscopy measurements. Optical microscopy shows a movement of agglomerates and texturing in the micrometer scale, whereas AC susceptometry and Mössbauer spectroscopy investigations reveal that the particles perform diffusive Brownian motion in the liquid polymer melt as separated particles rather than as large agglomerates. Furthermore, a texturing of MNP in the polymer matrix by a static magnetic field gradient was investigated. First results on the preparation of cross-linkable dextran esters are shown. Cross-linking after irradiation of the BNC prevents melting that can be used to influence texturing procedures.

Research on an axial-mounted dual magnetostrictive material rods-based electro-hydrostatic actuator

2021 ◽  
pp. 1045389X2110145
Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Magnetostrictive Material ◽  
Simulation Techniques ◽  
Motion State ◽  
New Type ◽  
Output Characteristics ◽  
Active Rectification

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.

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