Coating matters: the influence of coating materials on the optical properties of gold nanoparticles

Nanophotonics ◽  
2012 ◽  
Vol 1 (3-4) ◽  
pp. 199-220 ◽  
Author(s):  
Munish Chanana ◽  
Luis M. Liz-Marzán
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Colloidal Stability ◽  
Essential Element ◽  
Resonance Wavelength ◽  
Coating Material ◽  
Synthetic Approach ◽  
Primary Role ◽  
Coating Materials ◽  
Synthesis Procedure

AbstractAn essential element in the synthesis of nanomaterials based on gold nanoparticles comprises the control over parameters such as size, shape and composition, due to their strong influence on the properties of the particles. However, it is the coating material which often plays the primary role in tuning the size, morphology, and even plasmon resonance wavelength or mode multiplicity, as well as colloidal stability and functional versatility, ultimately determining the physical, chemical, optical, electronic and catalytic properties of the nanoparticles. Therefore, it is utterly important to select the adequate wet chemistry synthetic approach with the most suitable coating material for the preparation of gold nanoparticles with the desired requirements. Within this context, this review is focused on describing various types of organic and inorganic coating materials for gold nanoparticles that may notably affect their optical properties by either directly influencing the synthesis procedure or by changing their chemical and physical properties upon post-synthetic modifications, such that they exhibit novel and useful optical properties.

scholarly journals Coating Matters: Review on Colloidal Stability of Nanoparticles with Biocompatible Coatings in Biological Media, Living Cells and Organisms

2018 ◽  
Vol 25 (35) ◽  
pp. 4553-4586 ◽  
Author(s):  
Jonas Schubert ◽  
Munish Chanana
Keyword(s):  
Colloidal Stability ◽  
Biological Fluids ◽  
Chemical Properties ◽  
Coating Material ◽  
Living Systems ◽  
Biological Media ◽  
Coating Materials ◽  
Physico Chemical ◽  
Environment Temperature ◽  
To Come

Within the last two decades, the field of nanomedicine has not developed as successfully as has widely been hoped for. The main reason for this is the immense complexity of the biological systems, including the physico-chemical properties of the biological fluids as well as the biochemistry and the physiology of living systems. The nanoparticles’ physicochemical properties are also highly important. These differ profoundly from those of freshly synthesized particles when applied in biological/living systems as recent research in this field reveals. The physico-chemical properties of nanoparticles are predefined by their structural and functional design (core and coating material) and are highly affected by their interaction with the environment (temperature, pH, salt, proteins, cells). Since the coating material is the first part of the particle to come in contact with the environment, it does not only provide biocompatibility, but also defines the behavior (e.g. colloidal stability) and the fate (degradation, excretion, accumulation) of nanoparticles in the living systems. Hence, the coating matters, particularly for a nanoparticle system for biomedical applications, which has to fulfill its task in the complex environment of biological fluids, cells and organisms. In this review, we evaluate the performance of different coating materials for nanoparticles concerning their ability to provide colloidal stability in biological media and living systems.

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

High Density Gold Nanoparticles Within Three-Dimensionally Mesoporous SBA-15: Adsorption Behavior and Optical Properties

2015 ◽  
Vol 15 (9) ◽  
pp. 7060-7067 ◽  
Author(s):  
Xiaojuan Wang ◽  
Xiaoqing Yan ◽  
Renhong Li ◽  
Liping Xiao ◽  
Guicen Ma ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
High Density ◽  
Adsorption Behavior

THEORETICAL MODEL FOR THE CALCULATION OF OPTICAL PROPERTIES OF GOLD NANOPARTICLES

2010 ◽  
Vol 19 (03) ◽  
pp. 427-436
Author(s):  
A. MENDOZA-GARCÍA ◽  
A. ROMERO-DEPABLOS ◽  
M. A. ORTEGA ◽  
J. L. PAZ ◽  
L. ECHEVARRÍA
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Theoretical Model ◽  
Absorption Coefficient ◽  
Molecular System ◽  
Two Dimensional ◽  
Box Models ◽  
Solvent Environment ◽  
Absorption And Dispersion

We have developed an analytical method to describe the optical properties of nanoparticles, whose results are in agreement with the observed experimental behavior according to the size of the nanoparticle under analysis. Our considerations to describe plasmonic absorption and dispersion are based on the combination of the two-level molecular system and the two-dimensional quantum box models. Employing the optical stochastic Bloch equations, we have determined the system's coherence, from which we have calculated expressions for the absorption coefficient and refractive index. The innovation of this methodology is that it allows us to take into account the solvent environment, which induce quantum effects not considered by classical treatments.

Optical properties of nanostructured carbon and gold nanoparticle hybrids

2014 ◽  
Vol 1700 ◽  
pp. 79-82 ◽  
Author(s):  
Yuan Li ◽  
Nitin Chopra
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Hot Spots ◽  
Simulation Method ◽  
Dipole Approximation ◽  
Multilayer Graphene ◽  
Nanostructured Carbon ◽  
Near Surface ◽  
Scattering Effects ◽  
Dda Method

ABSTRACTWe report simulation of optical properties of hybrid geometry comprised of multilayer graphene shell encapsulated gold nanoparticles loaded with carbon nanotubes. The discrete dipole approximation (DDA) method was employed. The results indicated that the optical properties of encapsulated gold nanoparticles were not suppressed by the carbon material coating. Furthermore, low scattering effects were also observed. The simulation method helped visualize the near-surface normalized electric field, which is directly related to the intensity of hot spots on the surface of these hybrid nanoarchitectures.

scholarly journals Optical Properties of Star-Shaped Gold Nanoparticles

Nano Letters ◽  
2006 ◽  
Vol 6 (4) ◽  
pp. 683-688 ◽  
Author(s):  
Colleen L. Nehl ◽  
Hongwei Liao ◽  
Jason H. Hafner
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties
Sign in / Sign up

Export Citation Format

Share Document