Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Microfluidic active pressure and flow stabiliser
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology. (Centre of Natural Hazards and Disaster Science.)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology. (Centre of Natural Hazards and Disaster Science.)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology. (Centre of Natural Hazards and Disaster Science.)ORCID iD: 0000-0003-2744-1634
2021 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, article id 22504Article in journal (Refereed) Published
Abstract [en]

In microfluidics, a well-known challenge is to obtain reproducible results, often constrained by unstable pressures or flow rates. Today, there are existing stabilisers made for low-pressure microfluidics or high-pressure macrofluidics, often consisting of passive membranes, which cannot stabilise long-term fluctuations. In this work, a novel stabilisation method that is able to handle high pressures in microfluidics is presented. It is based on upstream flow capacitance and thermal control of the fluid's viscosity through a PID controlled restrictor-chip. The stabiliser consists of a high-pressure-resistant microfluidic glass chip with integrated thin films, used for resistive heating. Thereby, the stabiliser has no moving parts. The quality of the stabilisation was evaluated with an ISCO pump, an HPLC pump, and a Harvard pump. The stability was greatly improved for all three pumps, with the ISCO reaching the highest relative precision of 0.035% and the best accuracy of 8.0 ppm. Poor accuracy of a pump was compensated for in the control algorithm, as it otherwise reduced the capacity to stabilise longer times. As the dead volume of the stabiliser was only 16 nL, it can be integrated into micro-total-analysis- or other lab-on-a-chip-systems. By this work, a new approach to improve the control of microfluidic systems has been achieved.

Place, publisher, year, edition, pages
Springer Nature Springer Nature, 2021. Vol. 11, article id 22504
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:uu:diva-461143DOI: 10.1038/s41598-021-01865-4ISI: 000720520100014PubMedID: 34795333OAI: oai:DiVA.org:uu-461143DiVA, id: diva2:1619621
Funder
The Kamprad Family Foundation
Note

De två första författarna delar förstaförfattarskapet.

Available from: 2021-12-13 Created: 2021-12-13 Last updated: 2024-02-18Bibliographically approved
In thesis
1. Miniaturized fluid system for high-pressure analytics
Open this publication in new window or tab >>Miniaturized fluid system for high-pressure analytics
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

High-pressure chemistry can be used to determine the contents of blood or water samples and to discover new chemistries. However, working with chemistry at pressures of many tens, or even hundreds, of bars often requires expensive and stationary equipment, such as autoclaves or chromatographic systems like high-performance liquid chromatography (HPLC).

Since the introduction of microfluidics in the '90s, researchers have attempted to develop microfluidic chips as microreactors to speed up synthesis with faster mass and heat transfer. Other researchers have made efforts to create microfluidic chip-based HPLC to reduce the cost, increase the separation quality, speed up the analysis, and even enable portable systems for on-site medical or environmental analysis. Still, fully integrated systems have not yet been realized due to a lack of fluidic control components.

This thesis presents novel methods for on-chip regulation and monitoring of pressure, flow, and temperature. Papers I and II specifically suggest a method for regulating backpressure and stabilizing pressure and flows using thermally controlled restrictors. Furthermore, a collaboration was made where a pressure-regulating chip was connected to an on-chip HPLC. The purpose of this was to activate sample plugs and therefore reduce the requirement for expensive surrounding equipment and enable portability, Paper III. Paper IV explores the use of a pressurized capsule to generate high-pressure flows that are coupled to a pressure-regulating chip to stabilize and regulate the pressure. Finally, an approach for integrating pressure sensors into high-pressure tolerant microchannels has been proposed, Paper V.

The work conducted has provided new insights into fluid dynamics. The regulating method employed in Paper I-IV utilizes a restrictor that alters the pressure drop as temperature changes, hence changing the viscosity of the fluid. Although this technology has been known since before, new understandings have emerged regarding how the compressibility of incompressible fluids must be considered at higher pressures. Additionally, the concept of buffer capacitance is presented, which is central when working with high-pressure microfluidics.

Through this thesis, discoveries of high-pressure microfluidics have been accomplished, which enable micro-total-analysis systems that could serve as portable HPLC equipment.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2024. p. 60
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 2366
Keywords
High-pressure, Microfluidics, Thermal regulation, Fluid mechanics, In-situ sensors, High-pressure analytics
National Category
Fluid Mechanics and Acoustics Materials Engineering
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-523408 (URN)978-91-513-2038-0 (ISBN)
Public defence
2024-04-05, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2024-03-13 Created: 2024-02-18 Last updated: 2024-03-13

Open Access in DiVA

fulltext(1845 kB)209 downloads
File information
File name FULLTEXT01.pdfFile size 1845 kBChecksum SHA-512
c3319944904ece0ee9f4c3a3217ef33a94ce9848365799da346a0a5a514a4f42024a620671ee88d8bb796d4140a09c8abf8e9ee160cb104dea7f2495c68516c1
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMed

Authority records

Södergren, SimonSvensson, KarolinaHjort, Klas

Search in DiVA

By author/editor
Södergren, SimonSvensson, KarolinaHjort, Klas
By organisation
Microsystems Technology
In the same journal
Scientific Reports
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
Total: 209 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 168 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf