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Double positive effect of adding hexaethyelene glycol when optimizing the hybridization efficiency of a microring DNA detection assay

[Display omitted] •The hybridization efficiency of a DNA assay was investigated based on SOI microring resonators.•A 4-fold increase in efficiency was obtained by using HEG as backfilling agent, as well as improving robustness.•The dual polarization microring technique shows that HEG reorients the D...

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Bibliographic Details
Published in:Applied surface science 2017-05, Vol.405, p.321-328
Main Authors: Van Eeghem, Anabelle, Werquin, Sam, Hoste, Jan-Willem, Goes, Arne, Vanderleyden, Els, Bienstman, Peter, Dubruel, Peter
Format: Article
Language:English
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Summary:[Display omitted] •The hybridization efficiency of a DNA assay was investigated based on SOI microring resonators.•A 4-fold increase in efficiency was obtained by using HEG as backfilling agent, as well as improving robustness.•The dual polarization microring technique shows that HEG reorients the DNA in an upright position.•Hybridizing at 35°C and with a buffer containing 50v/v% of formamide greatly improves the robustness. In this paper, a method for detection of DNA molecules using silicon-on-insulator (SOI) microring resonators is described. The influence of temperature and the use of formamide on the hybridization efficiency were studied. It was shown that 50v/v% of formamide in the hybridization buffer can ensure hybridization when working close to physiological temperature. Furthermore, the use of hexaethylene glycol (HEG) as backfilling agent was studied in order to resolve issues of non-specific adsorption to the surface. The results indicated that not only non-specific binding was reduced significantly but also that HEG improves the orientation of the DNA probes on the surface. This led to a 4-fold increase in hybridization efficiency and thus in an equal decrease in the detection limit, compared to hybridization without the use of HEG. An improvement in robustness of the assay was also observed. This DNA reorientation hypothesis was confirmed by studying the thickness and density of the layers by using dual polarization microring sensing. Finally, the different steps in the sensing experiment were characterized in more detail by static contact angle (SCA) and X-ray photoelectron spectroscopy (XPS) analysis. The results showed quantitatively that the surface modifications were successful.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2017.02.064