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Bacteria counting with impedance spectroscopy in a micro probe station
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.ORCID iD: 0000-0002-5496-9664
2006 (English)In: Journal of physical chemistry B, ISSN 1520-6106, Vol. 110, no 20, 10165-10169 p.Article in journal (Refereed) Published
Abstract [en]

A method to quantify the density of viable biological cells in suspensions is presented. The method is implemented by low-frequency impedance spectroscopy and based on the finding that immobilized ions are released to move freely in the surrounding suspension when viable Escherichia coli cells are killed by a heat shock. The presented results show that an amount of ions corresponding to 2 × 108 unit charges are released per viable bacterium killed. A micro probe station with coplanar Ti electrodes was electrically characterized and used as a measuring unit for the impedance spectroscopy recordings. This unit is compatible with common microfabrication techniques and should enable the presented method to be employed using a flow-cell device for viable bacteria counting in miniaturized on-line monitoring systems.

Place, publisher, year, edition, pages
2006. Vol. 110, no 20, 10165-10169 p.
National Category
Other Materials Engineering
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
URN: urn:nbn:se:uu:diva-81756DOI: 10.1021/jp060148qPubMedID: 16706478OAI: oai:DiVA.org:uu-81756DiVA: diva2:109671
Available from: 2007-01-17 Created: 2009-02-26 Last updated: 2016-11-30Bibliographically approved
In thesis
1. Microfluidic Devices for Manipulation and Detection of Beads and Biomolecules
Open this publication in new window or tab >>Microfluidic Devices for Manipulation and Detection of Beads and Biomolecules
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis summarises work towards a Lab-on-Chip (LOC). The request for faster and more efficient chemical and biological analysis is the motivation behind the development of the LOC-concept.

Microfluidic devices tend to become increasingly complex in order to include, e.g. sample delivery, manipulation, and detection, in one chip. The urge for smart and simple design of robust and low-cost microdevices is addressed and discussed.

Design, fabrication and characterization of such microdevices have been demonstrated using low-cost polymer and glass microfabrication methods. The manufacturing is feasible, to a large extent, to perform outside the clean-room, and has subsequently been the chosen technique for most of the work. Issues of bonding reliability are solved by using polymer adhesive tapes.

A planar electrocapture device with LOC-compatibility is demonstrated where beads are immobilised and released in a flowing stream. Retention of nanoparticles by means of electric field-flow fractionation using transparent indium tin oxide electrodes is presented. Moreover, a cast PDMS 4-way crossing is enabling a combination of liquid chromatography and capillary electrophoresis to enhance separation efficiency. Sample transport issues and a new flow-cell design in a quartz crystal microbalance bioanalyzer are also investigated. Fast bacteria counting by impedance measurements, much requested by the pharmaceutical industry for biomass monitoring, is carried out successfully.

In conclusion, knowledge in micro system technology to build microdevices have been utilised to manipulate and characterise beads and cells, taking one step further towards viable Lab-on-Chip instruments.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 43 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 166
Keyword
Engineering physics, sensor, micro, dielectrophoresis, impedance, electrode, beads, cell, flow, bacteria, microfabrication, biosensor, electrocapture, microfluidic, planar, Lab on chip, µTAS, micro total analysis system, QCM, dispersion, field-flow fractionation, ITO, design, fabrication, Teknisk fysik
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-6746 (URN)91-554-6523-4 (ISBN)
Public defence
2006-04-28, Siegbahnsalen, Ångströmlaboratoriet, Lägerhyddsvägen1, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2006-04-07 Created: 2006-04-07 Last updated: 2011-12-09Bibliographically approved
2. Electrodynamic and Mechanical Spectroscopy Method Development and Analysis Relating to Materials with Biotechnological Applications
Open this publication in new window or tab >>Electrodynamic and Mechanical Spectroscopy Method Development and Analysis Relating to Materials with Biotechnological Applications
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Materials with biotechnological applications and materials that interact with the biological environment play an ever increasing role in our lives and society. In order to be able to tailor specific properties of these materials to suit their intended applications, it is important to gain a deeper understanding of the relationship between the material structure and its function.

This thesis contributes to the goal of achieving a better understanding of the functional properties of materials through the development of novel characterizing methods as well as the analysis of such materials. Electrodynamic and mechanical spectroscopy methods are developed or employed in the characterization of three classes of materials, namely, pharmaceutical, biomedical and biological materials.

Two electrodynamic methods utilizing conductivity measurements were developed for the investigation of drug release from pharmaceutical dosage forms, particularly in low liquid volumes. Furthermore, a mechanical spectroscopy method based on the split Hopkinson pressure bar setup was developed for the viscoelastic characterization of pharmaceutical compacts. It was shown that this method is a valuable complement to other methods of characterization.

Dielectric spectroscopy was integrated with microfabrication techniques to create a method for bacteria detection in a biotechnological application. As well, dielectric spectroscopy was used in the characterization of a novel biomimetic ionomer and was demonstrated to be a powerful tool for studying the bulk molecular dynamics of this functional material.

The work presented in this thesis not only provides an enhanced understanding of materials and their functional properties, but also presents new methods that should be useful for the future characterization of such materials.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 71 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 196
Keyword
Engineering physics, Teknisk fysik
Identifiers
urn:nbn:se:uu:diva-6932 (URN)91-554-6591-9 (ISBN)
Public defence
2006-05-30, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30 (English)
Opponent
Supervisors
Available from: 2006-05-09 Created: 2006-05-09 Last updated: 2010-04-19Bibliographically approved

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Welch, KenStrömme, Maria

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