Gold nanoparticles functionalized by rhodamine B isothiocyanate: A new tool to control plasmonic effects

Abstract

Gold nanoparticles with an average diameter of 10 nm, functionalized by the dye molecule rhodamine B isothiocyanate, have been synthesized. The resulting material has been extensively characterized both chemically, to investigate the bonding between the dye molecules and the nanoparticles, and physically, to understand the details of the aggregation induced by interaction between dye molecules on different nanoparticles. The plasmonic response of the system has been further characterized by measurement and theoretical simulation of the static UV-Vis extinction spectra of the aggregates produced following different synthesis procedures. The model parameters used in the simulation gave further useful information on the aggregation and its relationship to the plasmonic response. Finally, we investigated the time dependence of the plasmonic effects of the nanoparticles and fluorescence of the dye molecule using an ultrafast pump-probe optical method. By modulating the quantity of dye molecules on the surface of the nanoparticles it was possible to exert fine control over the plasmonic response of nanoparticles.

Designing an Optimal Ion Adsorber at the Nanoscale: The Unusual Nucleation of AgNP/Co2+–Ni2+ Binary Mixtures

“…[27][28][29] In this case, the shifts and the broadening of the plasmonic bands are a function of the percentage of ions in solution, allowing to extrapolate the dependence of the average growth rate of the aggregates on the chemical nature of the nanocomposites. 30 The mean size of the elongated clusters that spontaneously self-assemble in the Ni 2+ /AgNPs mixtures, grows with a much steeper slope with respect to the almost spherical-like aggre-…”

Visualization photofragmentation‐induced rhodamine B release from gold nanorod delivery system by combination two‐photon luminescence imaging with correlation spectroscopy

“…In this study, an AuNR‐rhodamine B (RB) nanodelivery system (AuNR‐RB) was assembled though the electrostatic interaction between negative charged RB and positive charged AuNR in alkaline condition for simulating the light‐controlled model . Before irradiation, RB fluorescence was effectively quenched by AuNR in the AuNR‐RB nanodelivery system.…”

Gold Nanoparticles and Nanorods in Nuclear Medicine: A Mini Review

“…Further, gold-based nanomaterials possess local surface plasmonic resonance (LSPR), which can be modulated by variations in shape, dimension, and aggregate formation [59,77,78]. The size and shape of particles modify the local electron confinement, which produces a variation in the LSPR absorption maxima.…”

“…AuNPs can be synthesized by means of several processes such as chemical, physical, and biological methods [24,[49][50][51]65]. A well-known bottom-up approach is a wet reduction in the presence of a capping agent [55,57,[59][60][61][62]64]. The obtained AuNPs can be easily investigated by microscope techniques, such as transmission electron microscope (TEM), scanning electron microscope (SEM), and atomic force microscope (AFM) [98][99][100][101][102].…”

“…In fact, they show remarkable chemical-physical properties, such as an easy modifiable morphology/size/surface, modulable optical absorption and scattering, photothermal and photoacoustic enhancements, and a wide surface/volume ratio that is suitable for interaction with the environment [50][51][52][53]. The gold surface can be functionalized and linked with drugs [54-57] and biomolecules, such as enzymes, antibodies, DNA, and peptides to achieve a specific site [58][59][60][61][62][63][64][65][66], and they are also studied to develop innovative antibacterial systems [67][68][69][70].In the wide field of advanced materials that represent the frontier where gold-based materials and nuclear medicine meet, this review provides an updated scenario of the progress in this young research field, focusing on gold nanoparticles (AuNPs) and nanorods (AuNRs) used in diagnosis and therapy, as schematized in Figure 1. The first key topic is the chemical preparation of gold-based nanomaterials, which is focused on spheres and rods.…”