Quantification of rolling circle amplified DNA using magnetic nanobeads and a Blu-ray optical pick-up unit
2015 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 67, no SI, 649-655 p.Article in journal (Refereed) Published
We present the first implementation of a Blu-ray optical pickup unit (OPU) for the high-performance low-cost readout of a homogeneous assay in a multichamber microfluidic disc with a chamber thickness of 600μm. The assay relies on optical measurements of the dynamics of magnetic nanobeads in an oscillating magnetic field applied along the light propagation direction. The laser light provided by the OPU is transmitted through the sample chamber and reflected back onto the photo detector array of the OPU via a mirror. Spectra of the 2nd harmonic photo detector signal vs. the frequency of the applied magnetic field show a characteristic peak due to freely rotating magnetic nanobeads. Beads bound to ~1μm coils of DNA formed off-chip by padlock probe recognition and rolling circle amplification show a different dynamics and the intensity of the characteristic peak decreases. We have determined the optimum magnetic bead concentration to 0.1mg/mL and have measured the response vs. concentration of DNA coils formed from Escherichia Coli. We have found a limit of detection of 10pM and a dynamic range of about two orders of magnitude, which is comparable to the performance obtained using costly and bulky laboratory equipment. The presented device leverages on the advanced but low-cost technology of Blu-ray OPUs to provide a low-cost and high-performance magnetic bead-based readout of homogeneous bioassays. The device is highly flexible and we have demonstrated its use on microfluidic chambers in a disc with a thickness compatible with current optical media mass-production facilities.
Place, publisher, year, edition, pages
2015. Vol. 67, no SI, 649-655 p.
Research subject Engineering Science with specialization in Nanotechnology and Functional Materials
IdentifiersURN: urn:nbn:se:uu:diva-239462DOI: 10.1016/j.bios.2014.09.097ISI: 000350076900095PubMedID: 25453736OAI: oai:DiVA.org:uu-239462DiVA: diva2:774623