Freestanding and Arrayed Nanoporous Microcylinders for Highly Active 3D SERS Substrate

Abstract

Surface-enhanced Raman scattering (SERS) has been considered as one of the most promising tools for molecular analysis. To develop practical platforms, a variety of nanoparticles and two-dimensional (2D) nanostructures have been prepared. However, low signal intensity or slow binding kinetics in conventional approaches limits their applications. To overcome these shortcomings, production and usage of three-dimensional (3D) nanostructures remain an important yet unmet need. In this paper, we report novel and effective SERS-active materials by fabricating hierarchically structured SiO 2 microcylinders decorated with gold nanoparticles. In order to fully develop 3D nanostructures, while maintaining fast diffusion of analyte molecules, we used self-assembled nanostructures of block-copolymers (BCPs) confined in the microholes of an imprinting mold; the BCPs could provide a template for producing 3D nanostructure composed of nanofibers with sub-100 nm diameter through their microphase separation, whereas the imprinting technique provided cylindrical geometry for the local confinement of the BCPs. Microcylinders with nanodomains were then transformed into microcylinders with 3D nanopores via reactive-ion etching and, subsequently, their nanopores were decorated by gold nanoparticles. The resultant 3D nanopores enable a high loading of gold nanoparticles and formation of abundant hot spots and microcylinders facilitate the fast diffusion of analyte molecules through the nanopores, resulting in significant enhancement of SERS intensity.

Monodipserse Nanostructured Spheres of Block Copolymers and Nanoparticles via Cross-Flow Membrane Emulsification

“…8,10 Recently, ellipsoid-and convex lens-shaped BCP particles were fabricated using a mixture of surfactants that had selective interaction with each block of the BCP domains at the particle surfaces. 8,[11][12][13][14] Due to their well-defined shape and internal nanostructure, these particles potentially will be useful as optical lens, 13 sensors, 15,16 high performance electrodes 17 and catalysts, 18 and dielectric resonators. 19 For implementing the particles into the practical applications mentioned above, it is necessary and essential to be able to produce monodispersed micron-or submicron-sized BCP particles on large production scale because their properties depend decisively on particle size.…”

3D Silver Nanoparticles Decorated Zinc Oxide/Silicon Heterostructured Nanomace Arrays as High-Performance Surface-Enhanced Raman Scattering Substrates

“…24,25 Compared with other conventional SERS substrates, 3D nanostructures are far superior due to the fact that they have the potential to further expand the arrangement of hotspots along the third dimension, which could in turn increase the hotspot density. 26,27 In addition, the 3D substrates can also supply larger surface area for adsorbing more probe molecules.…”

Simultaneous Synthesis and Assembly of Silver Nanoparticles to Three-Demensional Superstructures for Sensitive Surface-Enhanced Raman Spectroscopy Detection

“…It has been intensively studied for decades as a promising strategy for potentially enables the label-free detection of small biomolecules at low concentrations and even allows single-molecule level detections. 12- 14 The key factor for ideal SERS substrates is the amount of electromagnetic "hot spots", a point with a strongly enhanced local field, which allows extremely sensitive SERS detection. 14 Here, we report a one-pot approach for simultaneous synthesis and self-assembly of Ag NPs to micrometersized Ag superstructures in the presence of polymer brushes.…”

“…12- 14 The key factor for ideal SERS substrates is the amount of electromagnetic "hot spots", a point with a strongly enhanced local field, which allows extremely sensitive SERS detection. 14 Here, we report a one-pot approach for simultaneous synthesis and self-assembly of Ag NPs to micrometersized Ag superstructures in the presence of polymer brushes. The shapes of Ag superstructures can be tuned by adjusting the fabrication condition.…”