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Gold Colloid

Gold colloids are dispersed nanoparticles of gold in a liquid medium.
These colloidal suspensions exhibit unique optical, chemical, and biological properties that make them valuable in a variety of applications, includindsing biomedical imaging, drug delivery, and catalysis.
Gold colloids can be synthesized using different methods and their size, shape, and surface properties can be tuned to optimize performance.
Researchers use gold colloids to study phenomena such as surface plasmon resonance, Raman scattering, and catalytic activity.
Disovery and optimization of gold colloid protocols is an active area of research with many promising developments.

Most cited protocols related to «Gold Colloid»

1
Cryo-EM Tomographic Imaging Protocol
Degassed C-Flat 2/2-3C grids were glow discharged for 30 s at 20 mA. Virus or VLP solution was diluted with 10 nm colloidal gold; 2.5 μl of this mixture was applied to each grid and plunge frozen into liquid ethane using a FEI Vitrobot Mark 2. Grids were stored in liquid nitrogen until imaging.
Tomographic imaging was performed as described previously26 (link). Imaging was performed on a FEI Titan Krios at 300 keV using a Gatan Quantum 967 LS energy filter with a slit width of 20 eV and a Gatan K2xp direct detector. Tomograms were acquired from -60° to 60° with 3° steps using SerialEM27 (link) and a dose-symmetric tilt-scheme28 (link). Images were acquired in super-resolution mode.
Frames were aligned with either the K2Align software, which uses the MotionCorr algorithm29 (link), or with the frame alignment algorithm built into serialEM; frames were aligned and Fourier cropped to 4K x 4K, giving a final pixel size of 1.78 Å/pixel. Defocus for each tilt was determined by CTFFIND430 (link). Tilt images were filtered by cumulative electron dose using the exposure-dependent attenuation function and critical exposure constants described eleswhere26 (link),31 (link). Tilt images were CTF-corrected using ctfphaseflip32 (link) and tomograms were reconstructed using weighted back projection in IMOD33 (link). Tomograms with poor fiducial alignment were discarded (Extended Data Table 1). Poor fiducial alignment was defined as alignment residual above 1 pixel in 2x binned data or retaining fewer than 8 fiducial markers. CTF-corrected unbinned tomograms were binned by 2x (3.56 Å/pixel) and 4x (7.12 Å/pixel) with a Lanczos two-lobe anti-aliasing filter.
Detailed dataset parameters are given in Extended Data Table 1.
Wan W., Kolesnikova L., Clarke M., Koehler A., Noda T., Becker S, & Briggs J.A. (2017). Structure and assembly of the Ebola virus nucleocapsid. Nature, 551(7680), 394-397.
Publication 2017
Electrons Ethane Fiducial Markers Freezing Gold Colloid Nitrogen Reading Frames Tomography Virus
2
Whole-Mount Spermatocyte Chromosome Spread Protocol
The standard chromosome spreading protocol has been described previously for our laboratory (Lenzi et al., 2005 (link)). The nuclear contents of whole-mount spermatocytes (or oocytes) were displayed by drying down a cell suspension, in hypotonic buffer, from either testis, or ovary, in 1% paraformaldehyde containing 0.15% Triton X-100 (Peters et al., 1997 (link)). Whole testes or ovaries were incubated on ice for 60 min in hypotonic extraction buffer (HEB; 30 mM Tris, pH 8.2, 50 mM sucrose, 17 mM trisodium citrate dihydrate, 5 mM EDTA, 0.5 mM DTT, and 0.5 mM PMSF). Either a one-inch length of tubule, or a whole ovary, were placed in a 20-μl drop of 100 mM sucrose, pH 8.2, the tissue was macerated, and a second 20-μl drop of sucrose solution was added and the cell suspension was pipetted up and down several times. Remnant pieces of tubule were removed. Cleaned slides were dipped in the paraformaldehyde and Triton X-100 solution, and most liquid was drained off, such that only enough liquid remained to coat the slide. 20 μl of the cell suspension was added in one corner and the cells were slowly dispersed, first in a horizontal direction and then vertical. The remaining 20 μl of cell suspension was used to make a second slide and both were placed in a humid chamber to dry slowly at RT for 2 h. The slides were washed three times for 1 min in 0.4% Kodak Photo-Flo 200 and air dried for at least 15 min. For EM preparations, to make the SCs accessible to immunogold grains, the slides were DNaseI treated (1 μl/ml of DMEM) before being air dried (Moens et al., 2002 (link)). The slides were washed and blocked (three times for 10 min each) in PBS and incubated in primary antibodies overnight at RT in a humid chamber. Primary antibodies were used at varying concentrations, and generally a 10-fold higher concentration was used for EM than immunofluorescence. After washes, slides were incubated in secondary antibodies, conjugated to either fluorochrome or colloidal gold (Jackson ImmunoResearch Laboratories), for 2 h at 37°C. After washes the slides were mounted with ProLong Antifade (Invitrogen) for fluorescence microscopy. Images were captured on a Olympus IX81 microscope attached to a 12-bit Cooke Sensicam CCD instrument and sent to IP Lab software.
For EM, slides were incubated in 4% alcoholic phosphotungstic acid for 15 min, followed by three 1-min washes in 95% ethanol, to enhance visualization of MNs. Slides were air dried and then dipped in 0.25% formvar (Electron Microscopy Sciences) and air dried under glass. The plastic was scored, treated with 25% hydrofluoric acid, and floated off in water with attached cells. Plastic was transferred to EM grids and used for transmission EM (JEOL 1200EX).
Kolas N.K., Svetlanov A., Lenzi M.L., Macaluso F.P., Lipkin S.M., Liskay R.M., Greally J., Edelmann W, & Cohen P.E. (2005). Localization of MMR proteins on meiotic chromosomes in mice indicates distinct functions during prophase I. The Journal of Cell Biology, 171(3), 447-458.
Publication 2005
Alcoholics Antibodies Buffers Cells Cereals Chromosomes Edetic Acid Electron Microscopy Ethanol Fluorescent Antibody Technique Fluorescent Dyes Formvar Gold Colloid Hydrofluoric acid Microscopy Microscopy, Fluorescence Oocytes Ovary paraform Phosphotungstic Acid Sodium Citrate Dihydrate Spermatocytes Sucrose Testis Tissues Transmission, Communicable Disease Triton X-100 Tromethamine
3
Visualizing Epitope-Tagged Mitosomal Proteins

E. histolytica transformants expressing epitope-tagged mitosomal proteins were previously established [5] (link). Approximately 5×105 trophozoites were resuspended in 2 ml BI-S-33 medium and seeded onto a molybdenum disk (Nissin EM Co., JAPAN) in a well of a 24-well plate. After 15-min incubation at 35.5°C, the molybdenum disk that amoebas adhered to was removed and immediately immersed in liquid propane at −175°C. The disk was further fixed and sectioned as previously described [21] (link). The disk was reacted with primary antibody diluted at 1∶2000 (anti-Cpn60 antiserum) and 1∶500 (anti-HA monoclonal antibody) in phosphate-buffered saline containing 1.5% bovine serum albumin for overnight at 4°C. The samples were then reacted with colloidal gold-conjugated anti-rabbit or anti-mouse secondary antibody (1∶20) for 1 h at room temperature. Samples were examined by electron microscopy at Tokaii Microscopy., Inc (Nagoya, JAPAN).
Mi-ichi F., Makiuchi T., Furukawa A., Sato D, & Nozaki T. (2011). Sulfate Activation in Mitosomes Plays an Important Role in the Proliferation of Entamoeba histolytica. PLoS Neglected Tropical Diseases, 5(8), e1263.
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Publication 2011
Amoeba Antibodies, Anti-Idiotypic Electron Microscopy Epitopes Gold Colloid Immune Sera Immunoglobulins Microscopy Molybdenum Mus Phosphates Propane Proteins Rabbits Saline Solution Serum Albumin, Bovine Trophozoite
4
Cryo-ET of GroEL/GroES Complexes

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Publication 2009
Carbon Epistropheus Gold Colloid GroEL Protein Microscopy Tomography
5
Ultrastructure of Developing Mouse dLGN
To examine the ultrastucture of the developing dLGN, a total of eight C57/BL6 mice, at ages P7 (n = 2), P14 (n = 2), P21 (n = 2), and adult (9 months, n = 2) were used. Mice were first deeply anesthetized with isoflurane, then given an intraperitoneal injection of avertin (2.5%, 0.5–1 ml), and perfused through the heart with 2% paraformaldehyde and 2% glutaraldehyde in 0.1Mphosphate buffer. The brains were cut into 50–100-µm-thick coronal sections by using a Vibratome (Leica VT100E). Selected sections were postfixed in 2% osmium tetroxide and then dehydrated in an ethyl alcohol series and embedded in Durcupan resin. Because the mouse dLGN is less than 1 mm2 in coronal sections, we mounted the entire dLGN (at its largest extent, approximately 2.3 mm posterior to Bregma in the adult) on resin blocks for ultrastructural analysis. Ultrathin sections (on average 70 nm in thickness) were cut and every fifth section was collected on Formvar-coated nickel slot grids. Every fourth section in the series was stained to reveal the presence of GABA, by using previously published postembedding immunocytochemical techniques (Li et al., 2003 (link); Bickford et al., 2008 (link)) and a polyclonal, affinity-purified rabbit anti-GABA primary antibody (cat. no. A2052, Sigma, St. Louis, MO) diluted 1:2,000, and a goat anti-rabbit IgG antibody conjugated to 15-nm colloidal gold particles diluted 1:25 (British BioCell International, Cardiff, UK).
The immunogen used to produce the GABA antibody was GABA-bound to bovine serum albumin (BSA). The GABA antibody shows positive binding with GABA and GABA-keyhole limpet hemocyanin, but not BSA, in dot blot assays (Sigma product information). In mouse tissue, the GABA antibody stains neurons in the thalamic reticular nucleus and a subset of neurons in the dorsal thalamus. This labeling pattern is consistent with other GABAergic markers used in a variety of species to visualize interneurons. (Houser et al., 1980 (link); Hendrickson et al., 1983 (link); Oertel et al., 1983 (link); Fitzpatrick et al., 1984 (link); Montero and Singer, 1985 (link); Montero and Zempel, 1986 (link); Rinvik et al., 1987 (link); De Biasi et al., 1997 (link); Arcelli et al., 1997 (link); Wang et al., 2001 (link)).
The sections were subsequently stained with uranyl acetate and examined by using a Philips CM10 electron microscope. Images of each synaptic contact (identified by an accumulation of vesicles adjacent to a synaptic cleft) encountered within the examined sections were collected by using a digitizing camera (SIA-7C; SIA, Duluth, GA), or photographic plates that were subsequently scanned and digitized (SprintScan 45i; Polaroid, Waltham, MA). As described in detail in the Results section, each presynaptic and postsynaptic profile was categorized based on a variety of ultrastructural features, as well as the density of gold particles overlying them. Profile areas were measured from digital images of single sections by using Sigma Scan Software (SPSS, Chicago, IL). Images were imported into Adobe Photoshop software (San Jose, CA), where the brightness and contrast could be adjusted.
Bickford M.E., Slusarczyk A., Dilger E.K., Krahe T.E., Kucuk C, & Guido W. (2010). Synaptic Development of the Mouse Dorsal Lateral Geniculate Nucleus. The Journal of comparative neurology, 518(5), 622-635.
Publication 2010
Adult anti-IgG Antibodies, Anti-Idiotypic Antigens Biological Assay Brain Buffers Dot Immunoblotting Durcupan Electron Microscopy Ethanol Formvar gamma Aminobutyric Acid Glutaral Goat Gold Gold Colloid Heart Immunoglobulins Injections, Intraperitoneal Interneurons Isoflurane keyhole-limpet hemocyanin Mice, House Neurons Nickel Osmium Tetroxide paraform Rabbits Radionuclide Imaging Resins, Plant Serum Albumin, Bovine Singer Staining Thalamic Nuclei Thalamus Tissues tribromoethanol uranyl acetate

Most recents protocols related to «Gold Colloid»

1
Rapid SARS-CoV-2 Antigen Detection Assay
Purified anti-spike protein monoclonal antibodies (SpMA-01 and SpMA-02) were diluted in 50 mM PBS buffer (pH 7.4), 2 µg of capture mAb (SpMA-02) and 1 µg of goat anti-mouse antibody (Bethyl Lab, USA) and dropped onto a nitrocellulose membrane at the reading window to give the T and C, respectively. To 10 µL of colloidal gold conjugated anti-spike mAb (SpMA-01), an equal volume of 10% alkali-treated casein was mixed and placed onto a conjugate pad. The membranes were then dried at room temperature to immobilize antibodies. Samples of SARS-CoV-2 and its variants, or viruses and bacteria from the FDA pathogen panel were either diluted in PBS or treated with 100 mM TERGITOL-NP (prepared by mixing 334μL 100 mM Tergitol NP-9 with 666μL 100 mM Tergitol NP-10) followed by dilution with 150 µL of PBS. The samples were then placed onto sample application wells. Driven by capillary forces, the immunocomplex migrated up the membrane into the absorbent pad and after 10 to 15 minutes, the test results were evaluated visually. The selection of the optimal concentrations of the spike protein or pathogen antigens were visually inspected for Test (T-) and Control (C-) results. To determine the analytical sensitivity of spike protein in saliva or nasal samples, 200 ng of recombinant (S) was spiked into swabs and a 150μL extract was tested in the assay.
Mohammad S., Wang Y., Cordero J., Watson C., Molestina R., Rashid S, & Bradford R. (2023). Development and validation of a rapid and easy-to-perform point-of-care lateral flow immunoassay (LFIA) for the detection of SARS-CoV-2 spike protein. Frontiers in Immunology, 14, 1111644.
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Publication 2023
Absorbent Pads Alkalies Anti-Antibodies Antibodies Antibodies, Anti-Idiotypic Antigens Bacteria Biological Assay Buffers Capillaries Caseins Goat Gold Colloid Hypersensitivity Immobilization Mice, House M protein, multiple myeloma Nitrocellulose Nose NP 10 Pathogenicity S-phenyl-N-acetylcysteine Saliva SARS-CoV-2 Technique, Dilution Tergitol Tissue, Membrane Virus
2
Rapid SARS-CoV-2 Spike Protein Detection
The performances of the strips composed of the NC membrane, the single-layer conjugate pad, and the absorbent pad were tested. The strips were manually cut into 6 × 0.5 cm and housed in a plastic cassette. The test and control lines were spotted manually in a circle by spotting 2 µg/dot of anti-spike mAb (SpMA-02) and 1 µg/dot of goat anti-mouse antibody (I-0759, Sigma, USA) at the reading window to give the test (T) and control line (C), respectively. To 10 µL of colloidal gold conjugated anti-spike mAb (SpMA-01), an equal volume of 10% alkali-treated casein was mixed and placed onto a conjugate pad. The membranes were dried for 5 to 7 minutes at room temperature to immobilize antibodies. Different concentrations of recombinant S ranging from 200 ng to 12.5 ng in 150 µL buffer and the control Vero cell extract [200 ng in 150 µL of PBS (50 mM PBS, pH 7.4)] were placed onto the sample application point. Driven by capillary forces, the immunocomplex migrated up the membrane into the absorbent pad and the test results were evaluated visually after 10 -15 minutes, the test results were evaluated visually. The selection of the optimal concentrations of the spike protein was visually inspected for T and C line results. The limit of detection (LOD) was calculated accordingly.
Mohammad S., Wang Y., Cordero J., Watson C., Molestina R., Rashid S, & Bradford R. (2023). Development and validation of a rapid and easy-to-perform point-of-care lateral flow immunoassay (LFIA) for the detection of SARS-CoV-2 spike protein. Frontiers in Immunology, 14, 1111644.
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Publication 2023
Absorbent Pads Alkalies Antibodies Antibodies, Anti-Idiotypic Buffers Capillaries Caseins Cell Extracts Goat Gold Colloid Immobilization M protein, multiple myeloma Mus S-phenyl-N-acetylcysteine Tissue, Membrane
3
Anti-Spike Antibody Gold Conjugation
The anti-spike mAb (SpMA-01) of IgG1 isotype was selected for conjugation with a colloidal gold nanoparticle. The conjugation was optimized as described (28 (link)). Briefly, 6 to 10 µL of 1% K2CO3 (to adjust the pH to 6.5) was added to 1ml of colloidal gold solution in a glass tube, followed by 5 to 6 µg of anti-S SpMA-01 mAb and vortexed. The mAb-colloidal gold solution was incubated for 2 to 5 minutes at room temperature, followed by the addition of 20% BSA (final concentration approximately 0.1%), and the contents were transferred to an Eppendorf tube and centrifuged for 5 minutes in an Eppendorf centrifuge at 5000 RPM. The supernatant was removed, the pellet dissolved with 50 µL gold conjugation buffer.
Mohammad S., Wang Y., Cordero J., Watson C., Molestina R., Rashid S, & Bradford R. (2023). Development and validation of a rapid and easy-to-perform point-of-care lateral flow immunoassay (LFIA) for the detection of SARS-CoV-2 spike protein. Frontiers in Immunology, 14, 1111644.
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Publication 2023
Buffers Gold-50 Gold Colloid IgG1 Immunoglobulin Isotypes potassium carbonate S-phenyl-N-acetylcysteine
4
Cryo-EM Sample Preparation for Bacterial Cells
Plunge freezing was performed using an FEI Vitrobot (Thermo Fisher)53 (link). For cryoET sample preparation of bacterial cells, 10 nm colloidal gold fiducial markers (Sigma-Aldrich) were added to each sample at a ratio of 1:5 (v/v) to allow tilt image alignments. For Vitrobot setup, a filter paper (Whatman, 47 mm diameter) and a Teflon sheet were installed for single-sided blotting in a pre-cooled chamber (4 °C) with 100% humidity. EM grids (R2/2, Cu 200 mesh; Quantifoil Micro Tools) were glow-discharged for 45 s at 25 mA by PELCO easiGlow discharger. Sample aliquots (4 μl) were applied to each grid, incubated for 15 s and blotted for 6.5 s, followed by immediate plunge freezing in an ethane:propane mixture (37% v/v ethane:63% v/v propane)54 (link). Grids were stored in liquid nitrogen. Before loading of the samples into the cryo-electron microscope, the grids were clipped. For sample preparation, all bacterial samples were pelleted, and OD600 was adjusted to 2–2.5 before blotting. If required, L. monocytogenes or E. faecalis cells were exposed to 1,024 nM purified Ply006 or Ply007, respectively, followed by plunge freezing at the desired timepoints. For imaging of phage adsorption, bacterial cultures were adjusted to an OD600 of 0.1. Samples (95 µl) were then mixed with 5 µl of purified phage lysate (1011 p.f.u. ml−1), followed by 5 min incubation at room temperature.
Wohlfarth J.C., Feldmüller M., Schneller A., Kilcher S., Burkolter M., Meile S., Pilhofer M., Schuppler M, & Loessner M.J. (2023). L-form conversion in Gram-positive bacteria enables escape from phage infection. Nature Microbiology, 8(3), 387-399.
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Publication 2023
Adsorption Bacteria Bacteriophages Cells Cryoelectron Microscopy Ethane Fiducial Markers Gold Colloid Humidity Nitrogen Propane Strains Teflon
5
SARS-CoV-2 Antigen Detection Protocols

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Publication 2023
Antigens Buffers Enzyme Immunoassay Gold Colloid Head Immunoassay Immunoglobulins Nucleocapsid nucleocapsid phosphoprotein, SARS-CoV-2 Saliva SARS-CoV-2 Specimen Collection

Top products related to «Gold Colloid»

1
Vitrobot mark 4 by Thermo Fisher Scientific
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The Vitrobot Mark IV is a cryo-electron microscopy sample preparation instrument designed to produce high-quality vitrified specimens for analysis. It automates the process of blotting and plunge-freezing samples in liquid ethane, ensuring consistent and reproducible sample preparation.
2
1200 ex transmission electron microscope by JEOL
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The JEOL 1200 EX is a transmission electron microscope designed for high-resolution imaging and analysis of samples. It features a LaB6 electron source, high-resolution objective lens, and advanced imaging capabilities. The JEOL 1200 EX enables users to visualize and examine the fine details of specimens at the nanoscale level.
3
Bovine serum albumin (bsa) by Merck Group
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Bovine serum albumin (BSA) is a common laboratory reagent derived from bovine blood plasma. It is a protein that serves as a stabilizer and blocking agent in various biochemical and immunological applications. BSA is widely used to maintain the activity and solubility of enzymes, proteins, and other biomolecules in experimental settings.
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Colloidal gold by Merck Group
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Colloidal gold is a suspension of gold nanoparticles in a liquid. It exhibits unique optical properties due to the interaction of the gold nanoparticles with light.
6
Vitrobot by Thermo Fisher Scientific
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The Vitrobot is a laboratory instrument used for the preparation of cryo-vitrified samples for electron microscopy. It is designed to rapidly freeze samples in a controlled environment, preserving their native structure for high-resolution imaging.
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H 7650 by Hitachi
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The Hitachi H-7650 is a transmission electron microscope (TEM) designed for high-resolution imaging of materials. It provides a core function of nanoscale imaging and analysis of a wide range of samples.
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Tecnai g2 by Thermo Fisher Scientific
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More about "Gold Colloid"

Gold nanoparticles, colloidal Au, Au NPs, AuNPs, gold colloids, dispersed gold, gold sols, gold suspensions, and nanogold are all terms used to describe the unique class of material known as gold colloids.
These dispersed gold nanoparticles exhibit exceptional optical, chemical, and biological properties that make them highly valuable for a wide range of applications, including biomedical imaging, drug delivery, catalysis, and more.
Gold colloids can be synthesized using a variety of methods, allowing researchers to precisely control their size, shape, and surface characteristics to optimize performance.
Techniques like the Vitrobot Mark IV and JEOL 1200 EX transmission electron microscope are often employed to characterize and analyze these nanostructures.
Bovine serum albumin (BSA) is sometimes used to stabilize and functionalize the gold colloids.
The unique optical phenomena exhibited by gold colloids, such as surface plasmon resonance and Raman scattering, have made them invaluable tools for scientific research.
Cutting-edge imaging technologies, like the AMT 8 megapixel digital camera, enable the detailed study of these effects.
Colloidal gold, Vitrobot, H-7650, Tecnai G2, and Veleta camera are all important instruments and techniques used in gold colloid research and development.
Optimizing gold colloid protocols and unlocking their full potential is an active and rapidly evolving field of study.
Researchers are continuously exploring new synthesis methods, applications, and innovative ways to harness the remarkable properties of these nanomaterials.
The future of gold colloid research is indeed bright, with many promising developments on the horizon.