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Issue 21, 2013
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Lens-free imaging of magnetic particles in DNA assays

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We present a novel opto-magnetic system for the fast and sensitive detection of nucleic acids. The system is based on a lens-free imaging approach resulting in a compact and cheap optical readout of surface hybridized DNA fragments. In our system magnetic particles are attracted towards the detection surface thereby completing the labeling step in less than 1 min. An optimized surface functionalization combined with magnetic manipulation was used to remove all nonspecifically bound magnetic particles from the detection surface. A lens-free image of the specifically bound magnetic particles on the detection surface was recorded by a CMOS imager. This recorded interference pattern was reconstructed in software, to represent the particle image at the focal distance, using little computational power. As a result we were able to detect DNA concentrations down to 10 pM with single particle sensitivity. The possibility of integrated sample preparation by manipulation of magnetic particles, combined with the cheap and highly compact lens-free detection makes our system an ideal candidate for point-of-care diagnostic applications.

Graphical abstract: Lens-free imaging of magnetic particles in DNA assays

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Article information

12 Jun 2013
29 Jul 2013
First published
30 Jul 2013

Lab Chip, 2013,13, 4257-4262
Article type

Lens-free imaging of magnetic particles in DNA assays

F. Colle, D. Vercruysse, S. Peeters, C. Liu, T. Stakenborg, L. Lagae and J. Del-Favero, Lab Chip, 2013, 13, 4257
DOI: 10.1039/C3LC50707F

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