Denaturation strategies for detection of double stranded PCR products on GMR magnetic biosensor array

Giovanni Rizzi, Jung Rok Lee, Per Guldberg, Martin Dufva, Shan X. Wang, Mikkel F. Hansen

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Microarrays and other surface-based nucleic acid detection schemes rely on the hybridization of the target to surface-bound detection probes. We present the first comparison of two strategies to detect DNA using a giant magnetoresistive (GMR) biosensor platform starting from an initially double-stranded DNA target. The target strand of interest is biotinylated and detected by the GMR sensor by linking streptavidin magnetic nanoparticles (MNPs) to the sensor surface. The sensor platform has a dynamic detection range from 40 pM to 40 nM with highly reproducible results and is used to monitor real-time binding signals. The first strategy, using off-chip heat denaturation followed by sequential on-chip incubation of the nucleic acids and MNPs, produces a signal that stabilizes quickly but the signal magnitude is reduced due to competitive rehybridization of the target in solution. The second strategy, using magnetic capture of the double-stranded product followed by denaturing, produces a higher signal but the signal increase is limited by diffusion of the MNPs. Our results show that both strategies give highly reproducible results but that the signal obtained using magnetic capture is higher and insensitive to rehybridization.

Original languageEnglish
Pages (from-to)155-160
Number of pages6
JournalBiosensors and Bioelectronics
StatePublished - 15 Jul 2017

Bibliographical note

Publisher Copyright:
© 2016 Elsevier B.V.


  • DNA
  • DNA denaturation
  • GMR biosensor
  • Hybridization assay
  • Magnetic Biosensor
  • PCR


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