Nanoimprinted plastic substrates for enhanced surface plasmon resonance imaging detection.

Periodic nanostructures fabricated by Nanoimprint Litography (NIL) in low-cost plastic substrates and coated with thin gold film were explored for enhanced surface plasmon resonance imaging (SPRi) detection. Rigorous coupled-wave analysis was used to model the SPRi response of these nanostructured surfaces. Two-dimensional nanogratings and nanogrooves were fabricated on Zeonor 1060R(TM) by NIL and followed by metal deposition. The detection of refractive index changes in the dielectric layer due to bulk medium change, DNA immobilization and DNA hybridization events were monitored using SPRi to assess the corresponding signal amplification. The results indicate target-dependent sensitivity enhancement which is maximized for the detection of biomolecular binding events. The 500 nm period nanogrooves provided a 4 times SPR signal amplification compared to the conventional uniform gold film on SF-11 glass for DNA hybridization detection. Our work demonstrates that the use of nanoimprinted plastic substrates provides a low-cost solution for the SPR-based detection with sensitivity that meets the requirements in practical diagnostic applications.