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.
|Number of pages||11|
|Publication status||Published - 2012|
Cao, C., Birtwell, S. W., Høgberg, J., Morgan, H., Wolff, A., & Bang, D. D. (2012). Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA. Diagnostics, 2(4), 72-82. http://www.mdpi.com/2075-4418/2/4/72