Umeå University's logo

umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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
3D printed water-soluble scaffolds for rapid production of PDMS micro-fluidic flow chambers
Umeå University, Faculty of Science and Technology, Department of Physics.
Umeå University, Faculty of Science and Technology, Department of Physics.ORCID iD: 0000-0001-5475-1422
Umeå University, Faculty of Science and Technology, Department of Physics.
Umeå University, Faculty of Science and Technology, Department of Physics.
Show others and affiliations
2018 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 8, no 1, article id 3372Article in journal (Refereed) Published
Abstract [en]

We report a novel method for fabrication of three-dimensional (3D) biocompatible micro-fluidic flow chambers in polydimethylsiloxane (PDMS) by 3D-printing water-soluble polyvinyl alcohol (PVA) filaments as master scaffolds. The scaffolds are first embedded in the PDMS and later residue-free dissolved in water leaving an inscription of the scaffolds in the hardened PDMS. We demonstrate the strength of our method using a regular, cheap 3D printer, and evaluate the inscription process and the channels micro-fluidic properties using image analysis and digital holographic microscopy. Furthermore, we provide a protocol that allows for direct printing on coverslips and we show that flow chambers with a channel cross section down to 40 x 300 μm can be realized within 60 min. These flow channels are perfectly transparent, biocompatible and can be used for microscopic applications without further treatment. Our proposed protocols facilitate an easy, fast and adaptable production of micro-fluidic channel designs that are cost-effective, do not require specialized training and can be used for a variety of cell and bacterial assays. To help readers reproduce our micro-fluidic devices, we provide: full preparation protocols, 3D-printing CAD files for channel scaffolds and our custom-made molding device, 3D printer build-plate leveling instructions, and G-code.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018. Vol. 8, no 1, article id 3372
National Category
Other Materials Engineering Other Engineering and Technologies not elsewhere specified Other Physics Topics
Identifiers
URN: urn:nbn:se:umu:diva-144631DOI: 10.1038/s41598-018-21638-wISI: 000425500300044Scopus ID: 2-s2.0-85042263864OAI: oai:DiVA.org:umu-144631DiVA, id: diva2:1181373
Funder
Swedish Research Council, 2013-5379The Kempe Foundations, JCK-1622Available from: 2018-02-08 Created: 2018-02-08 Last updated: 2023-03-24Bibliographically approved
In thesis
1. Digital holography and image processing methods for applications in biophysics
Open this publication in new window or tab >>Digital holography and image processing methods for applications in biophysics
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Understanding dynamic mechanisms, morphology and behavior of bacteria are important to develop new therapeutics to cure diseases. For example, bacterial adhesion mechanisms are prerequisites for initiation of infections and for several bacterial strains this adhesion process is mediated by adhesive surface organelles, also known as fimbriae. Escherichia coli (E. coli) is a bacterium expressing fimbriae of which pathogenic strains can cause severe diseases in fluidic environments such as the urinary tract and intestine. To better understand how E. coli cells attach and remain attached to surfaces when exposed to a fluid flow using their fimbriae, experiments using microfluidic channels are important; and to assess quantitative information of the adhesion process and cellular information of morphology, location and orientation, the imaging capability of the experimental technique is vital.

In-line digital holographic microscopy (DHM) is a powerful imaging technique that can be realized around a conventional light microscope. It is a non-invasive technique without the need of staining or sectioning of the sample to be observed in vitro. DHM provides holograms containing three-dimensional (3D) intensity and phase information of cells under study with high temporal and spatial resolution. By applying image processing algorithms to the holograms, quantitative measurements can provide information of position, shape, orientation, optical thickness of the cell, as well as dynamic cell properties such as speed, growing rate, etc.

In this thesis, we aim to improve the DHM technique and develop image processing methods to track and assess cellular properties in microfluidic channels to shed light on bacterial adhesion and cell morphology. To achieve this, we implemented a DHM technique and developed image processing algorithms to provide for a robust and quantitative analysis of holograms. We improved the cell detection accuracy and efficiency in DHM holograms by developing an algorithm for detection of cell diffraction patterns. To improve the 3D detection accuracy using in-line digital holography, we developed a novel iterative algorithm that use multiple-wavelengths. We verified our algorithms using synthetic, colloidal and cell data and applied the algorithms for detecting, tracking and analysis. We demonstrated the performance when tracking bacteria with sub-micrometer accuracy and kHz temporal resolution, as well as how DHM can be used to profile a microfluidic flow using a large number of colloidal particles. We also demonstrated how the results of cell shape analysis based on image segmentation can be used to estimate the hydrodynamic force on tethered capsule-shaped cells in micro-fluidic flows near a surface.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2018. p. 59
Keywords
Digital holographic microscopy, image processing, image reconstruction, bacterial adhesion, cell morphology, algorithm development, software design, quantitative measurement, microfluidics, multidisciplinary research
National Category
Biophysics Computer Vision and Robotics (Autonomous Systems)
Research subject
Signal Processing; engineering science with specialization in microsystems technology
Identifiers
urn:nbn:se:umu:diva-150687 (URN)978-91-7601-915-3 (ISBN)
Public defence
2018-09-07, Naturvetarhuset, N430, Umeå, 13:15 (English)
Opponent
Supervisors
Available from: 2018-08-17 Created: 2018-08-15 Last updated: 2018-08-16Bibliographically approved
2. KNOW YOUR ENEMY: Characterizing Pathogenic Biomaterials Using Laser Tweezers
Open this publication in new window or tab >>KNOW YOUR ENEMY: Characterizing Pathogenic Biomaterials Using Laser Tweezers
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Diseases caused by pathogenic agents such as bacteria and viruses result in devastating costs on personal and societal levels. However, it is not just the emergence of new diseases that is problematic. Antibiotic resistance among bacteria makes uncomplicated infections difficult and lethal. Resilient disease-causing spores spread in hospitals, the food industry, and water supplies requiring effective detection and disinfection methods. Further, we face complex neurological diseases where no effective treatment or diagnostic methods exist. Thus, we must increase our fundamental understanding of these diseases to develop effective diagnostic, detection, disinfection, and treatment methods.

Classically, the methods used for detecting and studying the underlying mechanics of pathogenic agents work on a large scale, measuring the average macroscopic behavior and properties of these pathogens. However, just as with humans, the average behavior is not always representative of individual behavior. Therefore, it is also essential to investigate the characteristics of these pathogens on a single cell or particle level. 

This thesis develops and applies optical techniques to characterize pathogenic biomaterial on a single cell or particle level. At the heart of all these studies is our Optical Tweezers (OT) instrument. OT are a tool that allows us to reach into the microscopic world and interact with it. Finally, by combining OT with other experimental techniques, we can chemically characterize biomaterials and develop assays that mimic different biological settings. Using these tools, we investigate bacterial adhesion, disinfection, and detection of pathogenic spores and proteins.

Hopefully, the insights of these studies can lessen the burden on society caused by diseases by helping others develop effective treatment, diagnostic, detection, and disinfection methods in the future. 

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2022. p. 73
Keywords
Optical Tweezers, Laser Tweezers, Raman Spectroscopy, Bacterial Adhesion, Biophysics, Pili, Bacterial Spores, Endospores, Oocysts, Cryptosporidium, Optics
National Category
Biophysics Atom and Molecular Physics and Optics
Research subject
biology; Physics
Identifiers
urn:nbn:se:umu:diva-192471 (URN)978-91-7855-726-4 (ISBN)978-91-7855-727-1 (ISBN)
Public defence
2022-03-11, NAT.D.410, Naturvetarhuset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2022-02-18 Created: 2022-02-14 Last updated: 2022-02-15Bibliographically approved

Open Access in DiVA

fulltext(5697 kB)676 downloads
File information
File name FULLTEXT01.pdfFile size 5697 kBChecksum SHA-512
a3129f8fbca923c95484dc9520f67e84db97809ac2b40a9ea7c7c7981fd3d244dbc426a97ccb25727d013f70fc6094a991b53a3dd014441c5098b4c5fdd1da3a
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopus

Authority records

Dahlberg, TobiasStangner, TimHanqing, ZhangWiklund, KristerLundberg, PetterEdman, LudvigAndersson, Magnus

Search in DiVA

By author/editor
Dahlberg, TobiasStangner, TimHanqing, ZhangWiklund, KristerLundberg, PetterEdman, LudvigAndersson, Magnus
By organisation
Department of Physics
In the same journal
Scientific Reports
Other Materials EngineeringOther Engineering and Technologies not elsewhere specifiedOther Physics Topics

Search outside of DiVA

GoogleGoogle Scholar
Total: 681 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
urn-nbn

Altmetric score

doi
urn-nbn
Total: 7058 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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