20 research outputs found
Manipulation and Confinement of Single Particles Using Fluid Flow
High precision control of micro-
and nanoscale objects in aqueous
media is an essential technology for nanoscience and engineering.
Existing methods for particle trapping primarily depend on optical,
magnetic, electrokinetic, and acoustic fields. In this work, we report
a new hydrodynamic flow based approach that allows for fine-scale
manipulation and positioning of single micro- and nanoscale particles
using automated fluid flow. As a proof-of-concept, we demonstrate
trapping and two-dimensional (2D) manipulation of 500 nm and 2.2 μm
diameter particles with a positioning precision as small as 180 nm
during confinement. By adjusting a single flow parameter, we further
show that the shape of the effective trap potential can be efficiently
controlled. Finally, we demonstrate two distinct features of the flow-based
trapping method, including isolation of a single particle from a crowded
particle solution and active control over the surrounding medium of
a trapped object. The 2D flow-based trapping method described here
further expands the micro/nanomanipulation toolbox for small particles
and holds strong promise for applications in biology, chemistry, and
materials research
Manipulation and Confinement of Single Particles Using Fluid Flow
High precision control of micro-
and nanoscale objects in aqueous
media is an essential technology for nanoscience and engineering.
Existing methods for particle trapping primarily depend on optical,
magnetic, electrokinetic, and acoustic fields. In this work, we report
a new hydrodynamic flow based approach that allows for fine-scale
manipulation and positioning of single micro- and nanoscale particles
using automated fluid flow. As a proof-of-concept, we demonstrate
trapping and two-dimensional (2D) manipulation of 500 nm and 2.2 μm
diameter particles with a positioning precision as small as 180 nm
during confinement. By adjusting a single flow parameter, we further
show that the shape of the effective trap potential can be efficiently
controlled. Finally, we demonstrate two distinct features of the flow-based
trapping method, including isolation of a single particle from a crowded
particle solution and active control over the surrounding medium of
a trapped object. The 2D flow-based trapping method described here
further expands the micro/nanomanipulation toolbox for small particles
and holds strong promise for applications in biology, chemistry, and
materials research
Optimizing Sensitivity in a Fluid-Structure Interaction-Based Microfluidic Viscometer: A Multiphysics Simulation Study
Fluid-structure interactions (FSI) are used in a variety of sensors based on micro- and nanotechnology to detect and measure changes in pressure, flow, and viscosity of fluids. These sensors typically consist of a flexible structure that deforms in response to the fluid flow and generates an electrical, optical, or mechanical signal that can be measured. FSI-based sensors have recently been utilized in applications such as biomedical devices, environmental monitoring, and aerospace engineering, where the accurate measurement of fluid properties is critical to ensure performance and safety. In this work, multiphysics models are employed to identify and study parameters that affect the performance of an FSI-based microfluidic viscometer that measures the viscosity of Newtonian and non-Newtonian fluids using the deflection of flexible micropillars. Specifically, we studied the impact of geometric parameters such as pillar diameter and height, aspect ratio of the pillars, pillar spacing, and the distance between the pillars and the channel walls. Our study provides design guidelines to adjust the sensitivity of the viscometer toward specific applications. Overall, this highly sensitive microfluidic sensor can be integrated into complex systems and provide real-time monitoring of fluid viscosity
Hydrodynamic trap for single particles and cells
Trapping and manipulation of microscale and nanoscale particles is demonstrated using the sole action of hydrodynamic forces. We developed an automated particle trap based on a stagnation point flow generated in a microfluidic device. The hydrodynamic trap enables confinement and manipulation of single particles in low viscosity (1–10 cP) aqueous solution. Using this method, we trapped microscale and nanoscale particles (100 nm–15 μm) for long time scales (minutes to hours). We demonstrate particle confinement to within 1 μm of the trap center, corresponding to a trap stiffness of ∼10−5–10−4 pN∕nm