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Special Issue: Microfluidic Lab-on-a-Chip Platforms for High-Performance Diagnostics
Diagnostics 2012, 2(4), 72-82; doi:10.3390/diagnostics2040072
Article

Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA

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 and
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1 DTU-NANOTECH, Department of Micro and Nanotechnology, Technical University of Denmark, DTU Building 423, DK-2800 Kongens Lyngby, Denmark 2 School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK 3 DTU-VET, Diagnostic Laboratory, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870 Frederiksberg C, Denmark 4 DTU-FOOD, Laboratory of Applied Micro-Nanotechnology (LAMINATE), Diagnostic Engineering, Division of Food Microbiology, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark
* Author to whom correspondence should be addressed.
Received: 26 September 2012 / Revised: 24 October 2012 / Accepted: 26 November 2012 / Published: 29 November 2012
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Abstract

SU-8 epoxy-based negative photoresist has been extensively employed as a structural material for fabrication of numerous biological microelectro-mechanical systems (Bio-MEMS) or lab-on-a-chip (LOC) devices. However, SU-8 has a high autofluorescence level that limits sensitivity of microdevices that use fluorescence as the predominant detection workhorse. Here, we show that deposition of a thin gold nanoparticles layer onto the SU-8 surface significantly reduces the autofluorescence of the coated SU-8 surface by as much as 81% compared to bare SU-8. Furthermore, DNA probes can easily be immobilized on the Au surface with high thermal stability. These improvements enabled sensitive DNA detection by simple DNA hybridization down to 1 nM (a two orders of magnitude improvement) or by solid-phase PCR with sub-picomolar sensitivity. The approach is simple and easy to perform, making it suitable for various Bio-MEMs and LOC devices that use SU-8 as a structural material.
Keywords: gold nanoparticles; SU-8; autofluorescence; solid-phase PCR amplification; DNA hybridization gold nanoparticles; SU-8; autofluorescence; solid-phase PCR amplification; DNA hybridization
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).
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Cao, C.; Birtwell, S.W.; Høgberg, J.; Morgan, H.; Wolff, A.; Bang, D.D. Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA. Diagnostics 2012, 2, 72-82.

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