Quasi-3D Plasmonic Nanowell Array for Molecular Enrichment and SERS-Based Detection
Open Access
- 13 May 2020
- journal article
- research article
- Published by MDPI AG in Nanomaterials
- Vol. 10 (5), 939
- https://doi.org/10.3390/nano10050939
Abstract
We report on a quasi-three-dimensional (3D) plasmonic nanowell array with high structural uniformity for molecular detection. The quasi-3D plasmonic nanowell array was composed of periodic hexagonal Au nanowells whose surface is densely covered with gold nanoparticles (Au NPs), separated by an ultrathin dielectric interlayer. The uniform array of the Au nanowells was fabricated by nanoimprint lithography and deposition of Au thin film. A self-assembled monolayer (SAM) of perfluorodecanethiol (PFDT) was coated on the Au surface, on which Au was further deposited. Interestingly, the PFDT-coated Au nanowells were fully covered with Au NPs with an ultra-high density of 375 μm−2 rather than a smooth film due to the anti-wetting property of the low-energy surface. The plasmonic nanogaps formed among the high-density Au NPs led to a strong near-field enhancement via coupled localized surface plasmon resonance and produced a uniform surface-enhanced Raman spectroscopy (SERS) response with a small relative standard deviation of 5.3%. Importantly, the highly uniform nanostructure, featured by the nanoimprint lithography and 3D growth of densely-packed Au NPs, minimizes the spatial variation of Raman intensity, potentially providing quantitative analysis. Moreover, analyte molecules were highly concentrated and selectively deposited in nanowells when a water droplet containing the analyte was evaporated on the plasmonic substrate. The analyte formed a relatively thick overcoat in the nanowells near the triple line due to the coffee-ring effects. Combining 3D plasmonic nanowell substrates with molecular enrichments, highly sensitive detection of lactic acid was demonstrated. Given its combination of high sensitivity and signal uniformity, the quasi-3D plasmonic nanowell substrate is expected to provide a superior molecular detection platform for biosensing applications.This publication has 33 references indexed in Scilit:
- Self‐Assembly of Nanoparticle‐Spiked Pillar Arrays for Plasmonic BiosensingAdvanced Functional Materials, 2019
- Highly Sensitive and Selective Nanogap-Enhanced SERS Sensing PlatformNanomaterials, 2019
- Compact Integration of TiO2 Nanoparticles into the Cross-Points of 3D Vertically Stacked Ag Nanowires for Plasmon-Enhanced PhotocatalysisNanomaterials, 2019
- Sensitive and Reproducible Immunoassay of Multiple Mycotoxins Using Surface-Enhanced Raman Scattering Mapping on 3D Plasmonic Nanopillar ArraysSmall, 2018
- Culture-Free Detection of Bacterial Pathogens on Plasmonic Nanopillar Arrays Using Rapid Raman MappingACS Applied Materials & Interfaces, 2018
- Surface Energy‐Controlled SERS Substrates for Molecular Concentration at Plasmonic NanogapsAdvanced Functional Materials, 2017
- SERS-Activated Platforms for Immunoassay: Probes, Encoding Methods, and ApplicationsChemical Reviews, 2017
- 3D multilayered plasmonic nanostructures with high areal density for SERSRSC Advances, 2017
- Fabrication of Annealed Gold Nanostructures on Pre-Treated Glow-Discharge Cleaned Glasses and Their Used for Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) Detection of Adsorbed (Bio)moleculesSensors, 2017
- Nanostructured plasmonic substrates for use as SERS sensorsNano Convergence, 2016