Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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
Microfluidic preconcentration of amyloid beta samples
KTH, School of Chemical Science and Engineering (CHE).
2016 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Förkoncentrering av amyloid-beta-prov i mikrofluidiksystem (Swedish)
Abstract [en]

This study aimed to develop an extended isotachophoresis (eITP) system that could stack Amyloid beta (Aβ) peptides. The eITP was on-line coupled to electrospray ionization mass spectrometry (ESI-MS) in order to get a qualitative detection. The eITP buffer system was composed of ammonium acetate and acetic acid. By changing the concentrations in the leading electrolyte (LE) and trailing electrolyte (TE) the mobility gap could be tuned. Trypsin digested Cythochrome C (CytC digest) was used as model sample to investigate the behaviour of the eITP system. Using a commercial sheath-liquid interface it was concluded that some peptides were stacked in the eITP systems. Simulations had also been performed on the buffer system and the correlation between simulations and the experiments was good.

Aβ peptides could not be stacked in the system because of strong adsorption to the capillary wall. Because of this, three different capillary coatings were evaluated; polybrene (PB), poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA). The coating properties were investigated by measuring the electro-osmotic flow (EOF). The PB coating resulted in a reversed EOF that was higher than the velocity for the eITP system and could therefore not be used. The EOF-measurements indicated that neither the PEO- nor the PVA-coatings were stable or had complete coverage of the capillary wall and could therefore not stop the adsorption of Aβ peptides to the capillary wall. Instead, a sheathless interface was developed in order to decrease the total length of the capillary.

A single-circuit sheathless interface where the ESI-voltage provided the current for the CE was set-up and different ESI-needles were tested. However, the voltage could not be increased enough to give an effective separation without gaining too high ESI-current and a dual-circuit sheathless interface was therefore set up. The capillary length could be decreased to 30 cm using a commercial CE as HV-supply. This set-up gave a good separation of the CytC digest using the eITP systems and could in principle be used for a shorter capillary if a separate HV-supply is used instead of a commercial CE. The Aβ peptides were however still adsorbed by the capillary wall using this set-up and it could therefore not be determined if they were stacked in the eITP system or not.

Place, publisher, year, edition, pages
2016.
Keyword [en]
extended isotachophoresis, ESI-MS, Amyloid beta, coating, preconcentration
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-207064OAI: oai:DiVA.org:kth-207064DiVA: diva2:1095524
Available from: 2017-05-15 Created: 2017-05-15 Last updated: 2017-05-15Bibliographically approved

Open Access in DiVA

No full text

By organisation
School of Chemical Science and Engineering (CHE)
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

Total: 3 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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