Particle Focusing
Particle Focusing - Related Videos
10:14
Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles
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Cited by 19 •
2016
Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.
09:30
Focused Ion Beams
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2023
Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT As electron microscopes become more complex and widely used in research labs, it becomes more of a necessity to introduce their capabilities. Focused ion beam (FIB) is an instrument that can be employed in order to fabricate, trim, analyze and characterize materials on mico- and nano-scales in a wide variety of fields from nano-electronics to medicine. FIB...
03:37
Subatomic Particles
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2020
Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller subatomic particles: protons, neutrons, and electrons. These three particles account for the mass and the charge of an atom. The Discovery of the Electron The first clue about the subatomic structure came at the end of the 19th century when J.J. Thomson discovered the electron using a cathode ray tube. This apparatus consisted of a sealed glass...
11:59
High-speed Particle Image Velocimetry Near Surfaces
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Cited by 20 •
2013
A procedure for studying transient flows near boundaries using high-resolution, high-speed particle image velocimetry (PIV) is described here. PIV is a non-intrusive measurement technique applicable to any optically accessible flow by optimizing several parameter constraints such as the image and recording properties, the laser sheet properties, and analysis algorithms.
16:31
Echo Particle Image Velocimetry
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Cited by 10 •
2012
An echo particle image velocimetry (EPIV) system capable of acquiring two-dimensional fields of velocity in optically opaque fluids or through optically opaque geometries is described, and validation measurements in pipe flow are reported.
FAQs
In a microfluidic channel, inertial lift and drag act on suspended particles while secondary Dean flow contributes additional lateral transport. Their combined effect moves particles across the channel rather than leaving them distributed randomly. As particles migrate, they approach stable equilibrium positions, producing repeatable trajectories for downstream handling or measurement.
Channel geometry and flow conditions determine how the relevant fluidic forces are generated and how particles migrate laterally. Because these variables influence the balance among inertial lift, drag, and secondary Dean flow, they also influence the locations at which particles become stable. Engineering control of these conditions is therefore central to consistent focusing.
Sheath flow narrows the region available to suspended particles by hydrodynamically constraining them. This added control can reduce positional variation before particles reach a measurement or separation region. In practical devices, sheath flow therefore supports more uniform trajectories, which is important when instruments or downstream structures depend on predictable particle positions.
Flow cytometry and particle counting benefit from trajectories that are spatially consistent. Focusing reduces variation in where particles pass through a measurement region, helping the device distinguish and record individual events more accurately. The same principle supports higher-throughput operation because particles can be processed along a controlled path rather than across widely varying positions.
In cell-sorting systems, focused trajectories make the positions of particles or cells more predictable as they move through the device. That predictability supports automated separation and precise fluidic handling, while the controlled stream can help the system process many suspended objects efficiently. The engineering goal is a reproducible path that improves separation performance.
A basic engineering workflow starts with a microfluidic channel, introduces a suspension, and establishes flow conditions that generate lateral forces. Designers can incorporate sheath flow when additional hydrodynamic constraint is needed. They then use the resulting particle paths for handling, counting, sorting, or measurement, with uniform trajectories serving as the key practical outcome.
Particle focusing is especially relevant to lab-on-a-chip engineering because it combines controlled transport with compact device architectures. By reducing positional variation, it supports integrated analysis, automated separation, and high-throughput processing in small fluidic systems. These capabilities help engineers design diagnostic and other microfluidic devices that require consistent particle handling.