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Conducting Polymer Soft Actuators and Their Applications
Published in Peerawatt Nunthavarawong, Sanjay Mavinkere Rangappa, Suchart Siengchin, Mathew Thoppil-Mathew, Antimicrobial and Antiviral Materials, 2022
Micropumps are widely used in broader fields, including chemical, biomedical, and mechanical engineering systems. They are vital components of the microelectromechanical system (MEMS) devices used in chemical analyses, such as μ-TAS, and medical instruments for insulin and hormone delivery. In such applications, micropumps transport liquids slowly at microflow rates. However, it has recently become necessary to widen flow rate, achieve higher levels of flow rate resolution, and provide continuous transport for specific flows. Unfortunately, it was difficult to satisfy these requirements because none of the available actuators were sufficiently small, lightweight, or capable of slow and accurate movements similar to those of natural muscles. From antimicrobial and antiviral delivery viewpoints, transdermal drug delivery systems (TDDSs), such as the recently developed next-generation systems that include drug storage tanks and microneedles, have been attracting significant attention in recent years. In such systems, the micropump is essential for transporting fluids from the drug storage tank to the microneedles, which means that a highpressure head and highly accurate flow rate control are required. The micropump proposed in this chapter fully meets these requirements, and it is strongly anticipated that it will be incorporated in such systems in the future.
Mechanical Micromachines and Microsystems
Published in George K. Knopf, Kenji Uchino, Light Driven Micromachines, 2018
In addition to passive channels and active microvalves, many microfluidic systems also require micropumps to help drive fluid flow from one location to another. These MEMS-based pumps can also take advantage of electrostatic, magnetic, and piezoelectric forces. One example is an electrostatically-driven reciprocating displacement micropump (Figure 2.9) that can be created by bonding together several bulk micromachined silicon wafers. The bonding process is able to create a pumping cavity with a deformable membrane and two one-way check valves. The microfabrication process also enables the electrodes to be created inside the second cavity formed above the deformable membrane used to pump the fluid. In this manner the electrode is sealed from any electrically conductive solutions that are pumped. Since this is an electrostatic micromechanism, the reciprocating displacement pump will require a high voltage source (>100 V) in order to function properly. Another factor that influences the design requirements of the microfluidic pump is the type of fluid (liquid or gas) being transported. Some fluids are very sensitive to small temperature changes, high voltage potentials, or aggressive pumping actions. Synthetic insulin is an example of a medicinal fluid that cannot tolerate rapid oscillations or pumping actions without degrading.
Introduction
Published in Mohamed Gad-el-Hak, MEMS, 2005
Accelerometers for automobile airbags, keyless entry systems, dense arrays of micromirrors for high-definition optical displays, scanning electron microscope tips to image single atoms, micro heat exchangers for cooling of electronic circuits, reactors for separating biological cells, blood analyzers, and pressure sensors for catheter tips are but a few of the current usages. Microducts are used in infrared detectors, diode lasers, miniature gas chromatographs, and high-frequency fluidic control systems. Micropumps are used for ink jet printing, environmental testing, and electronic cooling. Potential medical applications for small pumps include controlled delivery and monitoring of minute amount of medication, manufacturing of nanoliters of chemicals, and development of artificial pancreas. The much sought-after lab-on-a-chip is promising to automate biology and chemistry to the same extent the integrated circuit has allowed large-scale automation of computation. Global funding for micro- and nanotechnology research and development quintupled from $432 million in 1997 to $2.2 billion in 2002. In 2004, the U.S. National Nanotechnology Initiative had a budget of close to $1 billion, and the worldwide investment in nanotechnology exceeded $3.5 billion. In 10 to 15 years, it is estimated that micro- and nanotechnology markets will represent $340 billion per year in materials, $300 billion per year in electronics, and $180 billion per year in pharmaceuticals.
Reliability Issues in State-of-the-Art Microfluidic Biochips: A Survey
Published in IETE Technical Review, 2023
CMF biochips are the first type of microfluidic biochip as a prominent solution to automate procedures of laboratory experiments in biochemistry and molecular biology. It generally consists of fixed micro pumps, micro valves and lasting inscribed, bounded, micron-dimension channels, interconnecting, as shown in Figure 1(a). Their various operations follow the principle of continuous fluid flow [11]. These CMF biochips are especially designed for those applications having high throughput. Such devices actuate the fluid flow either by electrokinetic mechanisms or by external pressure, integrated mechanical micropumps. CMF biochips consist of two-layer channel circuitry, where the control layer comprises of logic in triggering the pressure-driven microvalves in concern to close or open microchannels embedded in their flow layer [12]. These logic sequences to open or close participates are their activation sequences.
Numerical optimization of three-cavity magneto mercury reciprocating (MMR) micropump
Published in Engineering Applications of Computational Fluid Mechanics, 2021
Ali Mehrabi, Amir A. Mofakham, Mohammad Behshad Shafii
Thanks to advances in technology, high-performance micropumps were developed by researchers during the last decades to fulfill the needs of transferring a small, specified volume of fluid at a constant rate in microelectromechanical systems (MEMS) (Nguyen et al., 2002). Micropumps can be widely used in various application fields, including medical devices (Denishev & Trencheva, 2007), drug delivery (Denishev & Trencheva, 2007), and biomedical applications (Nisar et al., 2008). In the early 1990s, Smits (1990), a pioneer designer of micropumps, fabricated a micropump prototype as an alternative to consecutive insulin injections to diabetic patients. Since then, various types of micropumps have been developed. The micropumps can be generally classified into displacement and dynamic categories (Laser & Santiago, 2004). Reciprocating micropumps are a subcategory of the displacement, where a reciprocating motion of a piston or a diaphragm directly pumps a working fluid (Laser & Santiago, 2004). Dynamic micropumps continuously add energy to a working fluid by converting a type of non-mechanical energy into the pumping power (Iverson & Garimella, 2008). Since these micropumps do not have any moving parts, their design, fabrication, and maintenance are less challenging than those of the mechanical micropumps. Electro-osmotic (EO) (Zeng et al., 2001), electrohydrodynamic (EHD) (Fylladitakis et al., 2014; Richter & Sandmaier, 1990), and Magnetohydrodynamic (MHD) micropumps are the most prominent types of the dynamic category.
Effect of inlet and outlet angles on the flow performance of the ferrofluidic magnetic micropump
Published in Cogent Engineering, 2023
Sufian Shaker, Muhanad Hajjawi, Altaf Khan, Mohammad Kilani
Micropumps are enabling microfluidic devices capable of transferring fractions of milliliters of liquid against an imposed external pressure. They have an important role in many microfluidic applications including forced cooling of electrical components (Duan et al., 2014; Ma et al., 2011; Pramod & Sen, 2014), micro total analysis systems (Alrifaiy et al., 2012; Kovachev et al., 2010; Takeuchi et al., 2022; Verma & Bhattacharyya, 2021) and micro dosing and drug delivery systems (Bußmann et al., 2021; Hassan et al., 2022; Vante & Kanish, 2022).