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At least 343 records · Page 19Linked to original sources
PubMed1987

The existence of B/E and E receptors on Hep-G2 cells: a study using colloidal gold- and 125I-labeled lipoproteins.

The presence of specific receptors for apolipoprotein B (low-density lipoproteins) and apolipoprotein E (HDL-E) on Hep-G2 cells and human skin fibroblasts was studied by chemical methods and by electron microscopy using a differential gold labeling technique. Fibroblasts bound both types of lipoproteins to one and the same receptor (B/E receptor) as deduced from competition experiments with HDL-E and LDL. Labeled HDL-E, on the other hand, was only partially displaced by cold LDL but was completely displaced by unlabeled HDL-E. Scatchard analysis of lipoprotein binding to Hep-G2 cells revealed an approx 10 times higher binding affinity of apoE-containing lipoproteins as compared to apoB-containing ones. No differences between apoE- or apoB-containing lipoproteins with respect to the morphology of cell binding and intracellular processing were observed. The results are compatible with the concept that Hep-G2 cells possess two kinds of receptors, one specific for apoB- and apoE-containing lipoproteins (B/E receptor) and another specific for apoE only. From these studies we conclude that Hep-G2 cells may serve as a suitable model for studying the lipoprotein metabolism in the liver.

Apolipoproteins B↗
PubMed1994

Rapid detection of rotavirus by using colloidal gold particles labeled with monoclonal antibody.

A rapid single-step, sensitive and specific immunogold assay is described for detection of rotavirus. Murine monoclonal antibody (MCA) to the group antigen of rotavirus was dotted on a nitrocellulose paper strip. This was used to capture the rotavirus antigen which was revealed using a conjugate consisting of the MCA conjugated to gold particles. This assay detects 5 x 10(7) particles of rotavirus. It also acutely detected rotavirus from fecal samples, but failed to show any reaction with microscopically confirmed fecal samples containing G. lamblia and E. histolytica. The time taken for the test was approximately 10 min. Its versatility, simplicity, sensitivity and specificity makes it useful for third world countries.

Acute Disease↗
PubMed2004

Prostate-specific antigen immunosensing based on mixed self-assembled monolayers, camel antibodies and colloidal gold enhanced sandwich assays.

Prostate-specific antigen (PSA) is a valuable biomarker for prostate cancer screening. We developed a PSA immunoassay on a commercially available surface plasmon resonance biosensor. Our PSA receptor molecule consists of a single domain antigen-binding fragment, cAbPSA-N7, derived from dromedary heavy-chain antibodies and identified after phage display. It binds PSA with a high k(on) value of 1.9x10(6) M-1 s-1, and was covalently immobilised on a gold substrate via a mixed self-assembled monolayer (SAM) of alkanethiols by using carbodiimide-coupling chemistry in 10mM acetate buffer pH 5.5 to obtain an optimal pre-concentration. The best performing and optimised mixed SAM consisted of (10%) 16-mercapto-1-hexadecanoic acid (16-MHA) for covalent cAbPSA-N7 immobilisation and (90%) 11-mercapto-1-undecanol (11-MUOH) to minimise non-specific adsorption of the analyte. In this way, two advantages are incorporated in a single coupling layer. Up to 28 fmol/mm2 of cAbPSA-N7 could be immobilised and 30% of its binding sites participate actively in PSA interaction. In addition, the optimised layer showed also optimal performance to assess physiological samples. Although PSA concentrations as low as 10 ng/ml could be detected directly, this detection limit could be enhanced to PSA levels in the sub ng/ml range by introducing a sandwich assay involving a biotinylated secondary antibody and streptavidin modified gold nanoparticles. This approach realizes the PSA detection at clinical relevant concentrations.

Adsorption↗
PubMed2006

Electrochemical detection of hepatitis B surface antigen using colloidal gold nanoparticles modified by a sol-gel network interface.

BACKGROUND: A novel potentiometric immunosensor for the detection of hepatitis B surface antigen has been developed by self-assembling gold nanoparticles to a thiol-containing sol-gel network. METHODS: A cleaned gold electrode was first immersed in a hydrolyzed (3-mercaptopropyl) trimethoxysilane sol-gel solution to assemble a three-dimensional silica gel, and then gold nanoparticles were absorbed onto the thiol groups of the sol-gel network. Finally, hepatitis B surface antibody was assembled onto the surface of the gold nanoparticles. The self-assembling procedure was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Detection is based on the change in potentiometric response before and after the antigen-antibody reaction. RESULTS: Tests relating to the detection of hepatitis B surface antigen demonstrate that the potentiometric immunosensor exhibited a rapid potentiometric response (<4 min), with high sensitivity, good reproducibility, and long-term stability. The linear range was from 4 to 960 ng.mL(-1) with a detection limit of 1.9 ng.mL(-1) (S/N = 3) and the lifetime was 1 month. CONCLUSION: Analytical results of several specimens using the developed technique showed satisfactory agreement with those from an ELISA method. This method shows promise for detecting HBsAg in clinical specimens.

Calibration↗
PubMed1999

Ultrastructural identification of small granule prolactin (PRL) cells in goat adenohypophysis by the colloidal-gold method.

We describe ultrastructural characteristics of PRL cells with small secretory granules, immunostained with ovine antiserum, in adult Murciano-Granadina milking goats during anoestrus, the last third of gestation and lactation. This cell subtype is considered to comprise a stable population that decreases numerically during gestation and lactation, and that may change during these stages to show large granules.

Anestrus↗
PubMed2002

LR white post-embedding colloidal gold method to immunostain MBP, P0, NF and S100 in glutaraldehyde fixed peripheral nerve tissue.

A variety of immunocytochemical techniques are now widely used for the electron and light microscopic examination of biological samples. They are employed routinely for investigating the role of certain proteins in nervous tissue. Immunoelectron microscopic studies require the tissue to be fixed and embedded in a solid support, which may disrupt cellular structures and destroy crucial antigens. A technique of post-embedding with LR white resin has been developed, and it has been shown that certain antigens tolerate fixation with glutaraldehyde. In this study, we optimized a previous post-embedding method using low-water-miscible low-temperature embedding resin (LR white) to immunostain MBP, P0, NF and S100 proteins in peripheral nerves fixed with a relatively high concentration of glutaraldehyde found to be compatible with the morphology of normally compacted nerve fibers from humans and adult animals. The main difference in the procedures described here from previous ones is the elimination of vibratome sectioning, rendering this immunostaining technique more accessible to neuropathological laboratories using standard equipment for the ultrastructural study of peripheral nerves. It may prove of value for localization and quantification of these proteins in normal and pathological conditions.

Animals↗