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Sample pretreatment on a microchip with an integrated electrospray emitter
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signal Processing.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
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2006 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 27, no 11, 2075-2082 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2006. Vol. 27, no 11, 2075-2082 p.
Keyword [en]
Electrospray emitter, Microchip, PDMS, Sample pretreatment
National Category
Chemical Sciences Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-95129DOI: 10.1002/elps.200500763OAI: oai:DiVA.org:uu-95129DiVA: diva2:169220
Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2016-06-22Bibliographically approved
In thesis
1. Microfluidics in Surface Modified PDMS: Towards Miniaturized Diagnostic Tools
Open this publication in new window or tab >>Microfluidics in Surface Modified PDMS: Towards Miniaturized Diagnostic Tools
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is a strong trend in fabricating miniaturized total analytical systems, µTAS, for various biochemical and cell biology applications. These miniaturized systems could e.g. gain better separation performances, be faster, consume less expensive reagents and be used for studies that are difficult to access in the macro world. Disposable µTAS eliminate the risk of carry-over and can be fabricated to a low cost.

This work focused on the development of µTAS modules with the intentional use for miniaturized diagnostics. Modules for blood separation, desalting, enrichment, separation and ESI-MS detection were successfully fabricated. Surface coatings were additionally developed and evaluated for applications in µTAS with complex biological samples. The first heparin coating could be easily immobilized in a one-step-process, whereas the second heparin coating was aimed to form a hydrophilic surface that was able to draw blood or plasma samples into a microfluidic system by capillary forces.

The last mentioned heparin surface was further utilized when developing a chip-based sensor for performing CD4-count in human blood, an important marker to determine the stage of an HIV-infection.

All devices in this work were fabricated in PDMS, an elastomeric polymer with the advantage of rapid and less expensive prototyping of the microfabricated master. It was shown that PDMS could be considered as the material of choice for future commercial µTAS. The devices were intentionally produced using a low grade of fabrication complexity. It was however demonstrated that even with low complexity, it is possible to integrate several functional chip modules into a single microfluidic device.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 52 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 241
Keyword
Materials science, µTAS, micro total analysis system, PDMS, poly(dimethylsiloxane), microfluidics, heparin, blood filtration, on-chip, ESI-MS, desalting, QCM-D, biocompatible, CD4, capillary flow, lab-on-chip, microfabrication, enrichment, point-of-care, hydrophilic, oxidation, Materialvetenskap
Identifiers
urn:nbn:se:uu:diva-7270 (URN)91-554-6716-4 (ISBN)
Public defence
2006-12-08, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30
Opponent
Supervisors
Available from: 2006-11-17 Created: 2006-11-17Bibliographically approved
2. Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides
Open this publication in new window or tab >>Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Mikroskaliga verktyg för provpreparering, separation och detektion av neuropeptider
Abstract [en]

The analysis of low abundant biological molecules is often challenging due to their chemical properties, low concentration and limited sample volumes. Neuropeptides are one group of molecules that fits these criteria. Neuropeptides also play an important role in biological functions, which makes them extra interesting to analyze. A classic chemical analysis involves sampling, sample preparation, separation and detection. In this thesis, an enhanced solid supported microdialysis method was developed and used as a combined sampling- and preparation technique. In general, significantly increased extraction efficiency was obtained for all studied peptides. To be able to control the small sample volumes and to minimize the loss of neuropeptides because of unwanted adsorption onto surfaces, the subsequent analysis steps were miniaturized to a micro total analysis system (µ-TAS), which allowed sample pre-treatment, injection, separation, manipulation and detection.

In order to incorporate these analysis functions to a microchip, a novel microfabrication protocol was developed. This method facilitated three-dimensional structures to be fabricated without the need of clean room facilities.

The sample pre-treatment step was carried out by solid phase extraction from beads packed in the microchip. Femtomole levels of neuropeptides were detected from samples possessing the same properties as microdialysates. The developed injection system made it possible to conduct injections from a liquid chromatographic separation into a capillary electrophoresis channel, which facilitated for advanced multidimensional separations. An electrochemical sample manipulation system was also developed. In the last part, different electrospray emitter tip designs made directly from the edge of the microchip substrate were developed and evaluated. The emitters were proven to be comparable with conventional, capillary based emitters in stability, durability and dynamic flow range. Although additional developments remain, the analysis steps described in this thesis open a door to an integrated, on-line µ-TAS for neuropeptides analysis in complex biological samples.

Place, publisher, year, edition, pages
Uppsala: Kemiska institutionen, 2005. 62 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 64
Keyword
Analytical chemistry, Neuropeptides, Microchip, Enhanced microdialysis, Poly(dimethylsiloxane) (PDMS), Electrospray ionization (ESI), Multidimensional separation, Electrochemical manipulation, Mass spectrometry (MS), Capillary electrophoresis (CE), Microdevice, Microfabrication, Micro total analysis system (μ-TAS), Analytisk kemi
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-5838 (URN)91-554-6279-0 (ISBN)
Public defence
2005-06-03, Room B42, BMC, Uppsala, 10:15
Opponent
Supervisors
Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-12-08Bibliographically approved

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Lindberg, PeterDahlin, AndreasBergström, SaraThorslund, SaraNikolajeff, FredrikBergquist, Jonas

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