Acoustophoretic microfluidic chip for sequential elution of surface bound molecules from beads or cells

Abstract

An acoustophoresis-based microfluidic flow-chip is presented as a novel platform to facilitate analysis of proteins and peptides loosely bound to the surface of beads or cells. The chip allows for direct removal of the background surrounding the beads or cells, followed by sequential treatment and collection of a sequence of up to five different buffer conditions. During this treatment, the beads/cells are retained in a single flow by acoustic radiation force. Eluted peptides are collected from the outlets and subsequently purified by miniaturized solid-phase extraction and analyzed with matrix assisted laser desorption mass spectrometry. Fundamental parameters such as the system fluidics and dispersion are presented. The device was successfully applied for wash and sequential elution of peptides bound to the surface of microbeads and human spermatozoa, respectively.

Laborless, Automated Microfluidic Tandem Cell Processor for Visualizing Intracellular Molecules of Mammalian Cells

“…That is, diffusion-based mixing between two different solutions could be minimized. These medium-exchange devices have been employed in, for example, the effective isolation of cell nuclei, multistep coating of polymeric particles with polyelectrolyte multilayers, kinetics analysis of droplet-based extraction, and sequential elution of surface-bound molecules from cells . These systems hold great promise as new tools for precisely exchanging cell medium.…”

“…These medium-exchange devices have been employed in, for example, the effective isolation of cell nuclei, 24 multistep coating of polymeric particles with polyelectrolyte multilayers, 26 kinetics analysis of droplet-based extraction, 25 and sequential elution of surface-bound molecules from cells. 27 These systems hold great promise as new tools for precisely exchanging cell medium. However, there are limitations to increasing the number of medium-exchange steps, especially regarding the staining of intracellular molecules.…”

Continuous-Flow Cell Dipping and Medium Exchange in a Microdevice using Dielectrophoresis

“…Another technique, called deterministic lateral displacement, initially introduced as continuous-flow particle/cell separation method, was exploited [ 34 ]. Other techniques involve the use of standing bulk [ 35 ] or surface acoustic waves [ 36 ] to switch the micro-objects to different fluids. Tilted-angle standing surface acoustic wave technology is also reported in the literature to displace the cells for washing purpose [ 37 ].…”

Diamagnetic repulsion of particles for multilaminar flow assays

“…10 Here, multiple laminar streams of alternating reagent and washing buffer solutions are generated across a microuidic chamber, through which functionalised microparticles are deected in order to perform reactions. A number of forces can be applied in order to manipulate the particles across the chamber, including acoustic, [11][12][13] optical, 14 dielectrophoretic, 15 inertial forces, 16 biomolecular motors, 17,18 pinched ow, 19 hydrodynamic ltration, 20 and physical objects. [21][22][23] Magnetic forces 6,[24][25][26][27][28] have arguably been the most successful particle manipulation method in multilaminar ow systems, with functionalised magnetic particles being deected across laminar reagent streams via permanent magnets for applications including assays, [29][30][31][32][33][34][35] DNA hybridisation, 36,37 DNA extraction, 38,39 oligonucleotide capture, 40,41 and particle coating.…”