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
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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.
Cao C, Birtwell SW, Høgberg J, Morgan H, Wolff A, Bang DD. Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA. Diagnostics. 2012; 2(4):72-82.
Cao, Cuong; Birtwell, Sam W.; Høgberg, Jonas; Morgan, Hywel; Wolff, Anders; Bang, Dang D. 2012. "Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA." Diagnostics 2, no. 4: 72-82.