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Acoustic focusing of beads and cells in hydrogel droplets

Fornell, Anna LU ; Pohlit, Hannah ; Shi, Qian and Tenje, Maria LU (2021) In Scientific Reports 11(1).
Abstract

The generation of hydrogel droplets using droplet microfluidics has emerged as a powerful tool with many applications in biology and medicine. Here, a microfluidic system to control the position of particles (beads or astrocyte cells) in hydrogel droplets using bulk acoustic standing waves is presented. The chip consisted of a droplet generator and a 380 µm wide acoustic focusing channel. Droplets comprising hydrogel precursor solution (polyethylene glycol tetraacrylate or a combination of polyethylene glycol tetraacrylate and gelatine methacrylate), photoinitiator and particles were generated. The droplets passed along the acoustic focusing channel where a half wavelength acoustic standing wave field was generated, and the particles... (More)

The generation of hydrogel droplets using droplet microfluidics has emerged as a powerful tool with many applications in biology and medicine. Here, a microfluidic system to control the position of particles (beads or astrocyte cells) in hydrogel droplets using bulk acoustic standing waves is presented. The chip consisted of a droplet generator and a 380 µm wide acoustic focusing channel. Droplets comprising hydrogel precursor solution (polyethylene glycol tetraacrylate or a combination of polyethylene glycol tetraacrylate and gelatine methacrylate), photoinitiator and particles were generated. The droplets passed along the acoustic focusing channel where a half wavelength acoustic standing wave field was generated, and the particles were focused to the centre line of the droplets (i.e. the pressure nodal line) by the acoustic force. The droplets were cross-linked by exposure to UV-light, freezing the particles in their positions. With the acoustics applied, 89 ± 19% of the particles (polystyrene beads, 10 µm diameter) were positioned in an area ± 10% from the centre line. As proof-of-principle for biological particles, astrocytes were focused in hydrogel droplets using the same principle. The viability of the astrocytes after 7 days in culture was 72 ± 22% when exposed to the acoustic focusing compared with 70 ± 19% for samples not exposed to the acoustic focusing. This technology provides a platform to control the spatial position of bioparticles in hydrogel droplets, and opens up for the generation of more complex biological hydrogel structures.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
11
issue
1
article number
7479
publisher
Nature Publishing Group
external identifiers
  • pmid:33820916
  • scopus:85103994559
ISSN
2045-2322
DOI
10.1038/s41598-021-86985-7
language
English
LU publication?
yes
id
43a5549d-1d47-42c1-a28b-98c150b26367
date added to LUP
2021-04-20 09:55:49
date last changed
2024-06-16 12:38:45
@article{43a5549d-1d47-42c1-a28b-98c150b26367,
  abstract     = {{<p>The generation of hydrogel droplets using droplet microfluidics has emerged as a powerful tool with many applications in biology and medicine. Here, a microfluidic system to control the position of particles (beads or astrocyte cells) in hydrogel droplets using bulk acoustic standing waves is presented. The chip consisted of a droplet generator and a 380 µm wide acoustic focusing channel. Droplets comprising hydrogel precursor solution (polyethylene glycol tetraacrylate or a combination of polyethylene glycol tetraacrylate and gelatine methacrylate), photoinitiator and particles were generated. The droplets passed along the acoustic focusing channel where a half wavelength acoustic standing wave field was generated, and the particles were focused to the centre line of the droplets (i.e. the pressure nodal line) by the acoustic force. The droplets were cross-linked by exposure to UV-light, freezing the particles in their positions. With the acoustics applied, 89 ± 19% of the particles (polystyrene beads, 10 µm diameter) were positioned in an area ± 10% from the centre line. As proof-of-principle for biological particles, astrocytes were focused in hydrogel droplets using the same principle. The viability of the astrocytes after 7 days in culture was 72 ± 22% when exposed to the acoustic focusing compared with 70 ± 19% for samples not exposed to the acoustic focusing. This technology provides a platform to control the spatial position of bioparticles in hydrogel droplets, and opens up for the generation of more complex biological hydrogel structures.</p>}},
  author       = {{Fornell, Anna and Pohlit, Hannah and Shi, Qian and Tenje, Maria}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Acoustic focusing of beads and cells in hydrogel droplets}},
  url          = {{http://dx.doi.org/10.1038/s41598-021-86985-7}},
  doi          = {{10.1038/s41598-021-86985-7}},
  volume       = {{11}},
  year         = {{2021}},
}