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Microfluidics
Microfluidics refers to a system that manipulates a small amount of fluids (10−9 to 10−18 liters) using small channels with sizes of ten to hundreds of micrometres. It is a multidisciplinary field that involves molecular analysis, molecular biology, and microelectronics. It has practical applications in the design of systems that process low volumes of fluids to achieve multiplexing, automation, and high-throughput screening. Microfluidics emerged in the beginning of the 1980s and is used in the development of inkjet printheads, DNA chips, lab-on-a-chip technology, micro-propulsion, and micro-thermal technologies. Typically, micro means one of the following features: * Small volumes (μL, nL, pL, fL) * Small size * Low energy consumption * Microdomain effects Typically microfluidic systems transport, mix, separate, or otherwise process fluids. Various applications rely on passive fluid control using capillary forces, in the form of capillary flow modifying elements, akin to f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper-based Microfluidics
Paper-based microfluidics are microfluidic devices that consist of a series of hydrophilic cellulose or nitrocellulose fibers that transport fluid from an inlet through the porous medium to a desired outlet or region of the device, by means of capillary action. This technology builds on the conventional lateral flow test which is capable of detecting many infectious agents and chemical contaminants. The main advantage of this is that it is largely a passively controlled device unlike more complex microfluidic devices. Development of paper-based microfluidic devices began in the early 21st century to meet a need for inexpensive and portable medical diagnostic systems. Architecture Paper-based microfluidic devices feature the following regions: * Inlet: a substrate (typically cellulose) where liquids are dispensed manually. * Channels: hydrophilic sub-millimeter networks that guide liquid throughout a device. * Flow amplifiers: regions of varying geometry where the flow velocity i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Microfluidics
Microfluidics refers to the flow of fluid in channels or networks with at least one dimension on the micron scale. In open microfluidics, also referred to as open surface microfluidics or open-space microfluidics, at least one boundary confining the fluid flow of a system is removed, exposing the fluid to air or another interface such as a second fluid. Types of open microfluidics Open microfluidics can be categorized into various subsets. Some examples of these subsets include open-channel microfluidics, paper-based, and thread-based microfluidics. Open-channel microfluidics In open-channel microfluidics, a surface tension-driven capillary flow occurs and is referred to as spontaneous capillary flow (SCF). SCF occurs when the pressure at the advancing meniscus is negative. The geometry of the channel and contact angle of fluids has been shown to produce SCF if the following equation is true. < cos(\theta) Where pf is the free perimeter of the channel (i.e., the inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lab-on-a-chip
A lab-on-a-chip (LOC) is a device that integrates one or several laboratory functions on a single integrated circuit (commonly called a "chip") of only millimeters to a few square centimeters to achieve automation and high-throughput screening. LOCs can handle extremely small fluid volumes down to less than pico-liters. Lab-on-a-chip devices are a subset of microelectromechanical systems (MEMS) devices and sometimes called "micro total analysis systems" (μTAS). LOCs may use microfluidics, the physics, manipulation and study of minute amounts of fluids. However, strictly regarded "lab-on-a-chip" indicates generally the scaling of single or multiple lab processes down to chip-format, whereas "μTAS" is dedicated to the integration of the total sequence of lab processes to perform chemical analysis. History After the invention of microtechnology (≈1954) for realizing integrated semiconductor structures for microelectronic chips, these lithography-based technologies were soon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrohydrodynamics
Electrohydrodynamics (EHD), also known as electro-fluid-dynamics (EFD) or electrokinetics, is the study of the dynamics of electrically charged fluids. Electrohydrodynamics (EHD) is a joint domain of electrodynamics and fluid dynamics mainly focused on the fluid motion induced by electric fields. EHD, in its simplest form, involves the application of an electric field to a fluid medium, resulting in fluid flow, form, or properties manipulation. These mechanisms arise from the interaction between the electric fields and charged particles or polarization effects within the fluid. The generation and movement of charge carriers (ions) in a fluid subjected to an electric field are the underlying physics of all EHD-based technologies. The electric forces acting on particles consist of electrostatic (Coulomb) and electrophoresis force (first term in the following equation)., dielectrophoretic force (second term in the following equation), and electrostrictive force (third term in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microvalve
A microvalve is a microscale valve, i.e. a Microfluidics, microfluidic two-port component that regulates the flow between two fluidic ports. Microvalves are basic components in microfluidic devices, such as Lab-on-a-chip, labs-on-a-chip, where they are used to control the fluidic transport. During the period from 1995 to 2005, many microelectromechanical systems-based microvalves were developed. Microvalves found today can be roughly categorized as ''active'' microvalves and ''passive'' microvalves. Based on the medium they control, microvalves can be divided into gas microvalves and liquid microvalves. Based on their initial mode, microvalves can be divided into normally open, normally closed and bistable microvalves. Types Active microvalves Active mechanical microvalves consist of mechanically movable membrane or boss structure, coupled to an actuation method, that can close off an orifice, thus blocking the flow path between the inlet and outlet ports. The actuator can e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
