scholarly journals Metalloid gold clusters – past, current and future aspects

2021 ◽  
Author(s):  
Sebastian Kenzler ◽  
Andreas Schnepf
Keyword(s):  
Colloidal Gold ◽  
Gold Clusters ◽  
Gold Chemistry

Gold chemistry and the synthesis of colloidal gold always caught the attention of scientists. This review depicts the development of the chemistry of metalloid gold clusters over the last few decades and shows recent scientific developments.

Extremely Large Enhancement Factors in Surface-Enhanced Raman Scattering for Molecules on Colloidal Gold Clusters

1998 ◽  
Vol 52 (12) ◽  
pp. 1493-1497 ◽  
Author(s):  
Katrin Kneipp ◽  
Harald Kneipp ◽  
Ramasamy Manoharan ◽  
Eugene B. Hanlon ◽  
Irving Itzkan ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Colloidal Gold ◽  
Surface Enhanced Raman Scattering ◽  
Gold Clusters ◽  
Surface Enhanced ◽  
Enhancement Factors ◽  
Large Enhancement ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Strategies Insuring the Optimal use of IgG or FAB* Fragments Covalently Bound to 1.4 NM Nanogold ™ in Immunogold Labeling Procedures

1998 ◽  
Vol 4 (S2) ◽  
pp. 988-989
Author(s):  
C.A. Ackerley ◽  
A. Tilups ◽  
L.E. Becker
Keyword(s):  
Colloidal Gold ◽  
Fold Increase ◽  
Covalent Bonding ◽  
Gold Clusters ◽  
Immunogold Labeling ◽  
Limiting Factors ◽  
Particle Sizes ◽  
Fab Fragment ◽  
Fab Fragments ◽  
Astrocytoma Cell

Gold particles as markers in immunocytochemical procedures have undergone tremendous changes since their introduction by Faulk and Taylor (1). With the development of both small colloidal gold (<3 nm) and 1.4 nm gold clusters (Nanogold™) for immunocytochemical labeling, steric hindrance has been significantly reduced. In a comparative study using colloidal gold-anti CD3 complexes and particle sizes of 5 nm, 3 nm and less than 3 nm on surface labeling of lymphocytes there was a 1.5 fold increase in labeling density when 3 nm particles were used. There was no increase when smaller particles were used (unpublished data). In another unpublished experiment, labeling densities on an astrocytoma cell line were compared between 3nm colloidal gold-CD44 Fab’ fragments and 1.4 nm gold-CD44 Fab’ fragments. Again there was no detectable differences between particle sizes. The limiting factors remain the size of the IgG or Fab’ fragment, the ability to bind it whether by absorption or by covalent bonding without rendering it inactive and also the accessibility of the target molecule in the tissue.

Colloidal gold clusters formation and chemometrics for direct SERS determination of bioanalytes in complex media

2020 ◽  
Vol 224 ◽  
pp. 117380 ◽  
Author(s):  
Javier E.L. Villa ◽  
Marco A.S. Afonso ◽  
Diego P. dos Santos ◽  
Pablo A. Mercadal ◽  
Eduardo A. Coronado ◽  
...  
Keyword(s):  
Colloidal Gold ◽  
Gold Clusters ◽  
Complex Media

3-D organization of fibrinogen receptors using computer reconstruction and whole-mount microscopy

1988 ◽  
Vol 46 ◽  
pp. 30-31
Author(s):  
E. T. O'Toole ◽  
R. R. Hantgan ◽  
J. C. Lewis
Keyword(s):  
Whole Blood ◽  
Colloidal Gold ◽  
Blood Platelets ◽  
Cell Contact ◽  
Computer Assisted ◽  
Adherent Cells ◽  
Differential Centrifugation ◽  
Computer Reconstruction ◽  
Sds Page ◽  
Whole Mount

Thrombocytes (TC), the avian equivalent of blood platelets, support hemostasis by aggregating at sites of injury. Studies in our lab suggested that fibrinogen (fib) is a requisite cofactor for TC aggregation but operates by an undefined mechanism. To study the interaction of fib with TC and to identify fib receptors on cells, fib was purified from pigeon plasma, conjugated to colloidal gold and used both to facilitate aggregation and as a receptor probe. Described is the application of computer assisted reconstruction and stereo whole mount microscopy to visualize the 3-D organization of fib receptors at sites of cell contact in TC aggregates and on adherent cells.Pigeon TC were obtained from citrated whole blood by differential centrifugation, washed with Ca++ free Hank's balanced salts containing 0.3% EDTA (pH 6.5) and resuspended in Ca++ free Hank's. Pigeon fib was isolated by precipitation with PEG-1000 and the purity assessed by SDS-PAGE. Fib was conjugated to 25nm colloidal gold by vortexing and the conjugates used as the ligand to identify fib receptors.

Crystal structure images of large gold clusters and growing crystals by HRTEM

1984 ◽  
Vol 42 ◽  
pp. 428-429
Author(s):  
L.R. Wallenberg ◽  
J.-O. Bovin ◽  
G. Schmid
Keyword(s):  
Crystal Structure ◽  
Nucleation And Growth ◽  
Close Packing ◽  
Gold Clusters ◽  
Molecular Weight Determination ◽  
Growth Mechanisms ◽  
Starting Point ◽  
Different Types ◽  
Nucleation And Growth Mechanisms ◽  
Points Of View

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.

The Application of Protein A-Gold Immunocytochemistry to Studies of Protein Secretion

1985 ◽  
Vol 43 ◽  
pp. 426-429
Author(s):  
George H. Herbener ◽  
Antonio Nanci ◽  
Moise Bendayan
Keyword(s):  
Tissue Section ◽  
Colloidal Gold ◽  
Unit Area ◽  
Protein A ◽  
Extracellular Proteins ◽  
Gold Complex ◽  
Second Step ◽  
Igg Antibodies ◽  
Tissue Sections ◽  
Antigenic Sites

Protein A-gold immunocytochemistry is a two-step, post-embedding labeling procedure which may be applied to tissue sections to localize intra- and extracellular proteins. The key requisite for immunocytochemistry is the availability of the appropriate antibody to react in an immune response with the antigenic sites on the protein of interest. During the second step, protein A-gold complex is reacted with the antibody. This is a non- specific reaction in that protein A will combine with most IgG antibodies. The ‘label’ visualized in the electron microscope is colloidal gold. Since labeling is restricted to the surface of the tissue section and since colloidal gold is particulate, labeling density, i.e., the number of gold particles per unit area of tissue section, may be quantitated with ease and accuracy.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Intralysosomal Accumulation of Colloidal Gold-Low Density Lipoprotein Conjugates in Chloroquine-Treated Fibroblasts

1985 ◽  
Vol 43 ◽  
pp. 546-547 ◽  
Author(s):  
Dean A. Handley ◽  
Cynthia M. Arbeeny ◽  
Larry D. Witte
Keyword(s):  
Colloidal Gold ◽  
Cultured Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Coated Vesicle ◽  
Low Density ◽  
Cholesterol Esters ◽  
Cultured Fibroblasts ◽  
Surface Receptors ◽  
Ldl Particles

Low density lipoproteins (LDL) are the major cholesterol carrying particles in the blood. Using cultured cells, it has been shown that LDL particles interact with specific surface receptors and are internalized via a coated pit-coated vesicle pathway for lysosomal catabolism. This (Pathway has been visualized using LDL labeled to ferritin or colloidal gold. It is now recognized that certain lysomotropic agents, such as chloroquine, inhibit lysosomal enzymes that degrade protein and cholesterol esters. By interrupting cholesterol ester hydrolysis, chloroquine treatment results in lysosomal accumulation of cholesterol esters from internalized LDL. Using LDL conjugated to colloidal gold, we have examined the ultrastructural effects of chloroquine on lipoprotein uptake by normal cultured fibroblasts.

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