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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

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

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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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) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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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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