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- Werr, Gabriel, 1991-, et al.
(author)
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Integrated thin film resistive sensors for in situ temperature measurements in an acoustic trap
- 2019
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In: Journal of Micromechanics and Microengineering. - : IOP PUBLISHING LTD. - 0960-1317 .- 1361-6439. ; 29:9, s. 140-141
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Journal article (peer-reviewed)abstract
- This work presents an acoustic trap with integrated thin film sensors to monitor temperature variations during operation. The acoustic trap is wet-etched in glass with a thermally bonded glass lid and the thin-film sensors are integrated during fabrication. We evaluated the performance of the integrated temperature sensors and measured a temperature sensitivity of +/- 0.01 degrees C and confirmed that the read-out of the thin film sensors was not affected neither by the ionic conductivity of the solution nor the addition of microparticles into the acoustic trap. From the experiments we observed a temperature increase of the acoustic trap during operation as a result of the dissipative heating of the the piezoelectric element used to actuate the trap. We also showed that when external convective cooling was applied to the system, the temperature increase of the acoustic trap was higher than the temperature increase of the piezoelectric element itself. This shows the importance of using integrated temperature sensors in acoustic trapping to monitor the local environmental conditions.
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| 2. |
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| 3. |
- Fornell, Anna, et al.
(author)
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An acoustofluidic platform for non-contact trapping of cell-laden hydrogel droplets compatible with optical microscopy
- 2019
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In: Biomicrofluidics. - : AIP Publishing. - 1932-1058. ; 13
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Journal article (peer-reviewed)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 mu l/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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| 4. |
- Fornell, Anna, et al.
(author)
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Trapping of Cell-Laden Hyaluronic Acid-Acrylamide Hydrogel Droplets using Bulk Acoustic Waves
- 2019
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In: 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII). - : IEEE. - 9781538681046 - 9781728120072 ; , s. 2352-2355
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Conference paper (peer-reviewed)abstract
- In this paper an acoustofluidic system to trap hydrogel droplets is shown. The presented trapping method is label-free, biocompatible and operated in non-contact mode. The results show that the droplets can be trapped at flow rates up to 76 mu L/min which corresponds to an average flow speed of 3.2 mm/s. Moreover, it is shown that the droplets can be trapped for several hours, thus allowing for studies of the encapsulated cells over time. An application of the system is shown by performing on-chip cell nuclei staining.
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