Nanoimprinted plastic substrates for enhanced surface plasmon resonance imaging detection

Area of Science:

• Nanotechnology
• Plasmonics
• Biomedical Engineering

Background:

• Surface Plasmon Resonance Imaging (SPRi) is a label-free technique for detecting biomolecular interactions.
• Conventional SPRi often relies on expensive substrates and can lack sufficient sensitivity for certain diagnostic applications.
• Developing cost-effective and highly sensitive SPRi platforms is crucial for widespread adoption in diagnostics.

Purpose of the Study:

• To explore the use of periodic nanostructures fabricated by Nanoimprint Lithography (NIL) on low-cost plastic substrates for enhanced SPRi detection.
• To model and experimentally assess the signal amplification capabilities of these nanostructured surfaces.
• To evaluate the performance of the developed platform for detecting biomolecular binding events, such as DNA hybridization.

Main Methods:

• Fabrication of two-dimensional nanogratings and nanogrooves on Zeonor 1060R(TM) plastic substrates using Nanoimprint Lithography (NIL).
• Coating of nanostructured surfaces with a thin gold film.
• Modeling of the SPRi response using rigorous coupled-wave analysis.
• Monitoring refractive index changes using SPRi to detect bulk medium changes, DNA immobilization, and DNA hybridization.

Main Results:

• Rigorous coupled-wave analysis was employed to model the SPRi response of nanostructured surfaces.
• Periodic nanostructures, specifically 500 nm period nanogrooves, were successfully fabricated on plastic substrates via NIL.
• SPRi experiments demonstrated target-dependent sensitivity enhancement, with a significant amplification observed for biomolecular binding.
• The nanogroove structures achieved a 4-fold SPR signal amplification for DNA hybridization detection compared to conventional uniform gold films.

Conclusions:

• Nanoimprinted periodic nanostructures on low-cost plastic substrates offer a viable approach for enhanced SPRi detection.
• The developed platform provides a significant signal amplification, particularly for biomolecular binding events like DNA hybridization.
• This technology presents a cost-effective solution for SPR-based detection, meeting the sensitivity requirements for practical diagnostic applications.