title: Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA.
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.
authors: DTU-NANOTECH, Department of Micro and Nanotechnology, Technical University of Denmark, DTU Building 423, DK-2800 Kongens Lyngby, Denmark. ccao@ntu.edu.sg.
authors: Cuong
authors: C
authors: Cao
authors: School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK. s.birtwell@soton.ac.uk.
authors: Sam W
authors: SW
authors: Birtwell
authors: DTU-VET, Diagnostic Laboratory, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870 Frederiksberg C, Denmark. jonho@vet.dtu.dk.
authors: Jonas
authors: J
authors: Høgberg
authors: School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK. hm@ecs.soton.ac.uk.
authors: Hywel
authors: H
authors: Morgan
authors: DTU-NANOTECH, Department of Micro and Nanotechnology, Technical University of Denmark, DTU Building 423, DK-2800 Kongens Lyngby, Denmark. anders.wolff@nanotech.dtu.dk.
authors: Anders
authors: A
authors: Wolff
authors: 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. ddba@food.dtu.dk.
authors: Dang Duong
authors: DD
authors: Bang
keywords: DNA hybridization; SU-8; autofluorescence; gold nanoparticles; solid-phase PCR amplification