Blocking Reagents and Additives
In a labeling experiment, background staining can be reduced by blocking steps before the introduction of immuno-reagents and by compounds added to the immuno-incubation media and washing solutions. Aurion’s blocking reagents and additives include ready-to-use Blocking Solutions, individual components for commonly used blocking solutions, and a proprietary incubation media additive, BSA-c™.
AURION Blocking Solutions are available in different specificities corresponding to the gold conjugate selected. AURION BSA-c™ is strongly recommended for preventing charge based background.

The signal-to-noise ratio determines the quality of any detection experiment. This ratio is in principle determined by the characteristics of specimen and detection reagents. With adequate blocking and incubation media, background reactions are minimized whereas specific reactions are not hampered.

Aurion has developed Blocking Solutions which effectively block 'sticky' surfaces by multi-point hydrophobic and charge-based interactions. The Blocking Solutions are specifically designed to meet the characteristics of each type of secondary conjugate.

Introduction

The AURION Blocking Solutions are used to prevent immunoreagents from binding non-specifically to specimens with "sticky" surface properties.

Procedures to eliminate background comprise three main steps:

• To suppress residual aldehyde activity
• To saturate multipoint hydrophobic moieties and positive charges with high molecular weight compounds such as those present in the AURION Blocking Solutions
• To reduce aspecific binding of immunoreagents caused by hydrophilic interaction with competing molecules in the incubation and washing solution. AURION BSA-c™ is a particularly effective reagent for this purpose.

These steps should be balanced for optimum results.

Product Description

AURION Blocking Solutions are prepared using specially selected compounds. All ruminant proteins are obtained from healthy livestock.

AURION Blocking solutions contain Bovine Serum Albumin and Cold Water Fish Skin Gelatine in phosphate buffered saline with sodium azide as preservative. Normal serum may have been added as indicated on the label. The blocking capacity of each lot is determined using a dot-spot test system as described by Moeremans et al., J. Immunol. Methods 74, (1984), 353.

Each package contains 30 ml of solution. It accommodates 300 specimens for light microscopy at 100 µl/specimen (~ 3 drops), or 1000 EM grids at 30 µl/specimen (~ 1 drop).

Specificity

Blocking Solutions are available in the following specificities:

• serum-free: for use with Protein A and Protein G Gold conjugates.
• with Normal Goat serum: for use with reagents based on secondary antibodies raised in Goat.
• with Normal Rabbit serum: for use with reagents based on secondary antibodies raised in Rabbit.
• with Normal Sheep serum: for use with reagents based on secondary antibodies raised in Sheep.
• with Normal Donkey serum: for use with reagents based on secondary antibodies raised in Donkey.

Storage

AURION Blocking Solutions 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.

Technical Tip

Blocking Solutions Application Instructions

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