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An acoustofluidic platform for non-contact trapping of cell-laden hydrogel droplets compatible with optical microscopy

Fornell, Anna LU ; Johannesson, Carl LU ; Searle, Sean S. ; Happstadius, Axel ; Tenje, Maria LU and Nilsson, Johan LU (2019) In Biomicrofluidics 13(4).
Abstract

Production of cell-laden hydrogel droplets as miniaturized niches for 3D cell culture provides a new route for cell-based assays. Such production can be enabled by droplet microfluidics and here we present a droplet trapping system based on bulk acoustic waves for handling hydrogel droplets in a continuous flow format. The droplet trapping system consists of a glass capillary equipped with a small piezoelectric transducer. By applying ultrasound (4 MHz), a localized acoustic standing wave field is generated in the capillary, trapping the droplets in a well-defined cluster above the transducer area. The results show that the droplet cluster can be retained at flow rates of up to 76 μl/min, corresponding to an average flow speed of 3.2... (More)

Production of cell-laden hydrogel droplets as miniaturized niches for 3D cell culture provides a new route for cell-based assays. Such production can be enabled by droplet microfluidics and here we present a droplet trapping system based on bulk acoustic waves for handling hydrogel droplets in a continuous flow format. The droplet trapping system consists of a glass capillary equipped with a small piezoelectric transducer. By applying ultrasound (4 MHz), a localized acoustic standing wave field is generated in the capillary, trapping the droplets in a well-defined cluster above the transducer area. The results show that the droplet cluster can be retained at flow rates of up to 76 μl/min, corresponding to an average flow speed of 3.2 mm/s. The system allows for important operations such as continuous perfusion and/or addition of chemical reagents to the encapsulated cells with in situ optical access. This feature is demonstrated by performing on-chip staining of the cell nuclei. The key advantages of this trapping method are that it is label-free and gentle and thus well-suited for biological applications. Moreover, the droplets can easily be released on-demand, which facilitates downstream analysis. It is envisioned that the presented droplet trapping system will be a valuable tool for a wide range of multistep assays as well as long-term monitoring of cells encapsulated in gel-based droplets.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biomicrofluidics
volume
13
issue
4
article number
044101
publisher
American Institute of Physics
external identifiers
  • scopus:85069042020
ISSN
1932-1058
DOI
10.1063/1.5108583
language
English
LU publication?
yes
id
430a4536-5414-4e3f-914a-fbfb95ea80ae
date added to LUP
2019-07-26 10:45:57
date last changed
2020-01-13 02:15:38
@article{430a4536-5414-4e3f-914a-fbfb95ea80ae,
  abstract     = {<p>Production of cell-laden hydrogel droplets as miniaturized niches for 3D cell culture provides a new route for cell-based assays. Such production can be enabled by droplet microfluidics and here we present a droplet trapping system based on bulk acoustic waves for handling hydrogel droplets in a continuous flow format. The droplet trapping system consists of a glass capillary equipped with a small piezoelectric transducer. By applying ultrasound (4 MHz), a localized acoustic standing wave field is generated in the capillary, trapping the droplets in a well-defined cluster above the transducer area. The results show that the droplet cluster can be retained at flow rates of up to 76 μl/min, corresponding to an average flow speed of 3.2 mm/s. The system allows for important operations such as continuous perfusion and/or addition of chemical reagents to the encapsulated cells with in situ optical access. This feature is demonstrated by performing on-chip staining of the cell nuclei. The key advantages of this trapping method are that it is label-free and gentle and thus well-suited for biological applications. Moreover, the droplets can easily be released on-demand, which facilitates downstream analysis. It is envisioned that the presented droplet trapping system will be a valuable tool for a wide range of multistep assays as well as long-term monitoring of cells encapsulated in gel-based droplets.</p>},
  author       = {Fornell, Anna and Johannesson, Carl and Searle, Sean S. and Happstadius, Axel and Tenje, Maria and Nilsson, Johan},
  issn         = {1932-1058},
  language     = {eng},
  month        = {07},
  number       = {4},
  publisher    = {American Institute of Physics},
  series       = {Biomicrofluidics},
  title        = {An acoustofluidic platform for non-contact trapping of cell-laden hydrogel droplets compatible with optical microscopy},
  url          = {http://dx.doi.org/10.1063/1.5108583},
  doi          = {10.1063/1.5108583},
  volume       = {13},
  year         = {2019},
}