Pluronic Block Copolymer-Mediated Interactions of Organic Compounds with Noble Metal Nanoparticles for SERS Analysis

Abstract

The composite silver and gold nanoparticles (AgNPs and AuNPs) coated with nonionic amphiphilic block copolymers (Pluronics L121, F68, or F127) are prepared by their adsorption under critical micelle concentrations. It is found that Pluronics bind to the surface of metal NPs as a very thin film by the hydrophobic association through poly(propylene oxide) block of the copolymers. The modification increases the colloidal stability of NPs with increasing hydrophilic-lipophilic balance of Pluronics in the order of L121, F127, and F68. In order to investigate the potentials of polymer coated noble metal NPs as surface-enhanced Raman spectroscopy (SERS) probes, fluorescent dyes and doxorubicin are used as model compounds. It is found that Pluronic component promotes the adsorption of these compounds on the composite NPs resulting in a considerable increase of Raman signal. This effect is attributed to increased concentration of the analyte molecules on the composite surface due to the hydrophobic and charge-charge interactions between the analytes and the Pluronic coat, and the stabilization of NPs by poly(ethylene oxide) blocks. The copolymer coated AgNPs show higher SERS activity than the counterparts prepared with AuNPs. Among the prepared composites, the AgNPs modified with Pluronic F127 containing extended poly(propylene oxide) and poly(ethylene oxide) blocks exhibit maximal Raman activity using rhodamine 6G (Rh6G) with a EF of 9.04 x 10(6). The results show that the developed Pluronic-based SERS probes can be used for sensitive and selective analysis of organic analytes.

Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68

“…Nanoparticles co-stabilization with pluronic™ did not show considerable modifications in particle size. The pluronic™ addition showed improvement also on colloidal stability and on the nanoparticles analytic characteristic of metals demonstrated through Raman [24]. …”

Solubilization of Aromatic Hydrocarbons in Ethylene Oxide‐Propylene Oxide Triblock Micelles: Location of Solubilizate and its Effect on Micelle Size from 2D NMR and Scattering Techniques

“…Their commercial use as surfactants dates back to the 1950s, and a basic understanding on their solution chemistry has been actively pursued for about the past 30 years [2][3][4][5]. Recently, these nonionic polymeric surfactants have been widely studied for fabrication of mesoporous materials and nanoparticles, for bioprocessing and as vehicles for drug delivery systems [6][7][8][9]. In water, these copolymer form core-shell micelles; the micellization of these amphiphiles is strongly dependant on temperature and the presence of additives like electrolytes, nonelectrolytes, hydrotropes and ionic surfactants [10][11][12][13][14][15][16].…”

Organized Plasmonic Clusters with High Coordination Number and Extraordinary Enhancement in Surface‐Enhanced Raman Scattering (SERS)

“…This method has proven effective to form nanoparticle dimers with poly(vinyl pyrrolidone), poly(ethylene glycol), and poly(methyl methacrylate) 17. The use of polymers instead of DNA or organic linkers not only allows efficiently gluing colloidal particles with smaller interparticle gaps,18 but also concentrating the analytes19 within close proximity to the plasmonic surface while avoiding vibrational signal contamination, because the polymers display low Raman cross-sections 20…”