Nanoparticle-Functionalized Porous Polymer Monolith Detection Elements for Surface-Enhanced Raman Scattering

Abstract

The use of porous polymer monoliths functionalized with silver nanoparticles is introduced in this work for high-sensitivity surface-enhanced Raman scattering (SERS) detection. Preparation of the SERS detection elements is a simple process comprising the synthesis of a discrete polymer monolith section within a silica capillary, followed by physically trapping silver nanoparticle aggregates within the monolith matrix. A SERS detection limit of 220 fmol for Rhodamine 6G (R6G) is demonstrated, with excellent signal stability over a 24 h period. The capability of the SERS-active monolith for label-free detection of biomolecules was demonstrated by measurements of bradykinin and cyctochrome c. The SERS-active monoliths can be readily integrated into miniaturized micro-total-analysis systems for on-line and label-free detection for a variety of biosensing, bioanalytical, and biomedical applications.

Self-Assembly of High Density of Triangular Silver Nanoplate Films Promoted by 3-Aminopropyltrimethoxysilane

“…Generally, the sensing analysis has been done by directly mixing the silver colloids with the analyte solution [23]. Therefore, silver is considered to be a single use system as opposed to multiple uses for a silver thin film [24]. The silver thin film can easily be washed to remove the analyte from the surface to allow a second or potentially repeated analysis and this result alternatively helps to prove the repeatability of the sensing system.…”

Polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography

“…Nanoparticles were recently explored to functionalize the monoliths with specific selectivity. The approaches are divided into two categories: (i) direct encapsulation of nanoparticles into the monolith in the process of polymerization [21][22][23] and (ii) modification of surface with nanoparticles after monolith formation [24][25][26][27][28][29][30]. The latter approach results in a remarkable increase in the effective surface area of monolith, which was successfully applied for CEC and cLC separation, and solid-phase extraction as well.…”

Nano-Doped Monolithic Materials for Molecular Separation

“…The success has been attributed to the exceptional convective mass flow of fluids in monoliths, the capacity of the composite structure to direct metal nanostructures, the tuneable pore size, and high surface area enabling an enhanced interaction between target and SERS active surfaces [104,105]. In light of this, an AgNP-modified monolithic substrate for SERS was developed by Liu, White, and DeVoe [104] for a label-free detection of peptide bradykinin and cytochrome c. In addition, it was shown from their analysis that the copolymerisation of AgNP with acrylic-based polymeric monoliths synthesised by means of UV-radiation yielded low sensitivity in the detection of Rhodamine 6G (R6G dye) as compared to an AgNP-surface modified hydrophobic BMA-co-EDMA and GMA-co-SR454. Notably, the latter had a higher sensitivity towards R6G amongst the three set of analysis [104].…”

“…In light of this, an AgNP-modified monolithic substrate for SERS was developed by Liu, White, and DeVoe [104] for a label-free detection of peptide bradykinin and cytochrome c. In addition, it was shown from their analysis that the copolymerisation of AgNP with acrylic-based polymeric monoliths synthesised by means of UV-radiation yielded low sensitivity in the detection of Rhodamine 6G (R6G dye) as compared to an AgNP-surface modified hydrophobic BMA-co-EDMA and GMA-co-SR454. Notably, the latter had a higher sensitivity towards R6G amongst the three set of analysis [104]. Nevertheless, Navarro-Pascual-Ahuir, Lerma-García, Ramis-Ramos, Simó-Alfonso, and Herrero-Martínez [30] demonstrated that doping of AgNP into LMA-monoliths via copolymerisation or surface modification both led to changes in the chromatographic properties, relative to an unmodified LMA-monolith.…”