Immuno Gold Protein A

Immunogold Particle Sizes and Characteristics

Specificity
AURION offers the widest range of Immunogold Antibodies and they are prepared using the highest quality antibodies or binding agents available. All antibodies are immuno affinity purified and immuno cross-adsorbed to reduce non-specific reactions.

Storage
AURION Immunogold Antibodies have a guaranteed shelf life of 18 months from the date of quality control analysis. The products should be stored at 4-8°C. Freezing is not recommended.

Conventional Immunogold Reagents

Introduction
Immunogold Reagents are available in 4 size classes. The monodisperse size population makes the conjugates suited for multiple labeling with no overlap. The Conventional Immunogold Reagents are the classical conjugates in immuno electron microscopy; they are a good choice when the antigen is abundant and the accessibility of the antigen is relatively good.

The conventional labeling approach in transmission and scanning electron microscopy utilizes secondary immunogold reagents based on particles that can be observed without enhancement. These conjugates are suited for single and multiple labeling in electron microscopy, when the number of antigens available for binding is such that a relevant signal can be obtained.
The AURION Conventional Immunogold Reagents are built around colloidal gold particles with sizes of 6, 10, 15 or 25nm. The particle population is monodisperse and thus shows minimal size variation and overlap. Typically, the coefficient of variance for the 6 and 25nm particle size conjugates is less than 12%, whereas the 10 and 15nm size conjugates show less than 10% variation.

Product Description
AURION Conventional Immunogold Reagents are tailored to contain 10-20µg of specific protein/ml. The reagents are supplied in PBS with 1% Bovine Serum Albumin and 15mM NaN3 at an OD520nm of 1.0 to warrant prolonged cluster free storage.

The activity of each lot is determined using a dot-spot test system as described by Moeremans et al., J. Immunol. Methods, 74, (1984), 353. Actual lot specifications (size, variation and expiry date) are indicated on the accompanying package insert.

Two package sizes:

Regular package: for the labeling of 1000-2000 grids
Small package: for the labeling of 400-800 grids

Application Instructions
On-Grid Labeling
For most applications grids are floated on top of drops of dilute reagent displayed on a sheet of Parafilm™. The use of gold or nickel grids is recommended.

Whole mount and intact cell labeling
Specimens are kept floating in dilute reagent on a rocking table.

Recommended Incubation Solution:
PBS (10mM Phosphate buffer, 150mM NaCl)
0.1-0.2 % AURION BSA-C™
15mM NaN3
pH 7.4

Ultra Small Immunogold Reagents

Aurion Ultra Small Immunogold Reagents are prepared with subnanometer gold particles. These particles have far less influence on the adsorbed antibodies or detecting molecules, and consequently the conjugates behave as though they are uncoupled. In conjunction with the highly efficient and easy-to-use R-Gent SE-LM and SE-EM silver enhancement reagents, the Ultra Small Immunogold Reagents are the best choice for any application.

Introduction
Reduction of the gold particle size provides Ultra Small Immunogold Reagents with fundamentally different characteristics when compared with conjugates built around larger particles. While the Conventional Immunogold Reagents can be thought of as particles coated with proteins, Ultra Small Immunogold Reagents are proteins coated with one or more gold particles. With this structure, both the overall size of the conjugates, as well as steric hindrance are decreased.

The small gold particles also have a tight particle surface curvature which makes it less likely that a structured water dipole layer will build-up around the gold particles. Hence, the hydrodynamic radius of the ultra small gold colloids is reduced. Finally, small gold particles carry less net negative charge; thus, they undergo less charge determined repulsion when approaching the sample surface.

Ultra Small Immunogold Reagents have an average gold particle diameter of 0.8nm or less. These ultra small gold particles can be visualized directly in high angle annular dark-field-scanning TEM. However, the gold signal is normally visualized after increasing the particle diameter with silver enhancement. The reagents can be used in electron and light microscopy as well as in blotting experiments. The universal applicability makes it easy to compare results obtained with different procedures.

Product Description
AURION Ultra Small Immunogold Reagents contain 60-80µg of specific protein/ml for IgG conjugates. F(ab’)2, Fab and biotinylated albumin conjugates contain equimolar amounts of conjugated protein. The average gold cluster diameter is less than 0.8nm. They are used in conjunction with AURION R-Gent SE-EM or SE-LM silver enhancement reagents, developed for electron microscopy and light microscopy/immunoblotting respectively.
The reagents are supplied in PBS with 1% Bovine Serum Albumin and 15mM NaN3.
The activity of each lot is determined using a dot-spot test system as described by Moeremans et al., J. Immunol. Methods, 74, (1984), 353.
Two package sizes:
Regular package: for 1200 grids or 600 slides
Small package: for 480 grids or 240 slides

Application Instructions
Detailed information is provided in the package inserts and in the INFO section online.

Electron Microscopy
Post-embedding Labeling
Incubate thin sections by placing grids on drops of reagent arrayed on a sheet of Parafilm™. The use of nickel grids is recommended, especially if silver enhancement procedures are intended.

Pre-embedding Labeling
Float specimens in dilute reagent on a rocking table.

Light Microscopy
Slide or Coverslip Labeling
Apply a few drops of dilute reagent to cover the specimen.

Recommended Incubation Solution:
PBS (10mM Phosphate buffer, 150mM NaCl), 0.1-0.2 % AURION BSA-c™, 15mM NaN3, pH 7.4