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Integration of microfluidic sample handlingwith ultra-sensitive magnetic bioassay usinghigh-Tc Superconducting Quantum InterferenceDevice readout
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
2016 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Immunoassays are a very sensitive molecular diagnostics technique

that uses biochemical reactions to measure concentration of

biomolecules in a solution. ELISA is one of the most commonly used

type, based on fluorescence, in routine medicaldiagnostics. It is

time consuming and requires relatively large sample volumes.

Immunoassays based on magnetic detection are being developed. They

are faster, able to be made into point of care devices with

biological samples often lacking magnetic background. This project

focuses on developing an magnetic bioassay based on a high-Tc

SQUID with magnetic nanoparticles as tags. The expected

performance maybe two orders of magnitude better than ELISA

techniques, while not requiring several washing steps and being

able to perform in real time. Method of detection is based on

utilizing a padlock DNA probe-based recognition mechanism to

enhance the size ofviral flu RNA, binding the nanoparticles to the

padlocks and measuring the change in amplitude of the Brownian

relaxation peak of the unbound nanoparticles.

This thesis has been focused on developing a microfluidic sample

holder. Mircofluidics offer an advanced way to handle liquid

samples, with preparation, dilution, mixing and incubation on the

same chip, so called lab on a chip. During this thesis,

microfluidic channels made of PDMS were created. PDMS is a

suitable material because it is relatively cheap, easy to

manufacture and particles or padlocks do not bind to it.

Measurements of the real and imaginary parts of the AC

susceptibility as a function of concentration of both non

functionalized and functionalized magnetic nanoparticles

were performed in the microchannel with a volume of about 3 micro

liter. Extrapolating the results showed an equivalent iron content

sensitivity of 2*10^5 particles at 10 Hz. This result is about one

order of magnitude better than obtained in bulk samples of larger


Place, publisher, year, edition, pages
2016. , 59 p.
UPTEC Q, ISSN 1401-5773 ; 16002
National Category
Nano Technology
URN: urn:nbn:se:uu:diva-302734OAI: oai:DiVA.org:uu-302734DiVA: diva2:967379
Educational program
Master Programme in Materials Engineering
2016-05-13, Ångströmslaboratoriet, Uppsala, 13:24 (English)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2016-09-08Bibliographically approved

Open Access in DiVA

Master thesis report Emil Eriksson(10681 kB)18 downloads
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