Carrier-free formulations for recombinant antibodies

Standard rabbit monoclonal antibodies are typically stored in a phosphate-buffered saline (PBS) solution with carrier proteins like bovine serum albumin (BSA), and other additives such as glycerol and sodium azide.  

These components can hinder effective conjugation to fluorochromes, metals, oligonucleotides, and enzymes, so removing these proteins and additives enhances labeling. 

• BSA competes with the primary antibody for the label of interest, which greatly reduces the conjugation efficiency 
• Sodium azide in the antibody solution can be toxic to cells, limiting the antibody's use in cell culture 
• Sodium azide can also interfere with antibody conjugation and inhibits the activity of horseradish peroxidase (HRP) 

Endotoxin is an aggregate of acidic lipopolysaccharides (LPS) that is shed from bacteria and is a heat-stable ubiquitous contaminant. Although bacteria are often removed with a 0.2 μm sterilizing grade filter, LPS contamination is difficult to eliminate via filtering or autoclaving. ​​​​The presence of endotoxin can significantly impact both in vitro and in vivo experiments, causing non-specific cellular responses and false readings in cell-based assays. 

Our low endotoxin antibodies are designed for in vitro and in vivo studies, including neutralization, blocking, or activation/proliferation. 

Benefits of our low endotoxin, azide-free bioactive antibodies:

• Endotoxin levels ≤ 1 EU/ml, as determined by the LAL assay 

• Sodium azide, BSA and glycerol-free 

• Supplied at 1 mg/mL concentration 

• Quality tested in a range of applications, including flow cytometry and functional activity assays 

• Bulk sizes and custom concentrations available 

Our carrier-free formats are ideal for building multiplex assays with your own panel of conjugated antibodies.

Flow based-assays: 

• Cytometry by Time Of Flight (CyTOF®) is a novel flow cytometry platform that uses metal-conjugated antibodies to characterize and quantify more than 40 parameters simultaneously at the single-cell level. 

Multiplex IHC assays:

• Imaging mass cytometry™ (IMC) combines the advantages of metal-conjugated antibodies and immunohistochemical/immunocytochemical methods to study cell-cell interactions at the subcellular resolution and delineate tumor heterogeneity. 

• ​Cyclic immunofluorescence (CyCIF) involves repeatedly staining and imaging slides, making it a reliable and inexpensive method for multiplex imaging. 

In addition to ELISA assays, over 10,000 of our antibodies are available in a carrier-free format – BSA, azide, and glycerol-free – making them ideal for customization, antibody labeling, and functional assays.  

To enable complete flexibility, we now have over 4,000 matched antibody pairs and their individual capture and detector antibodies available in a carrier-free format, giving you the flexibility you need to adapt your pair to your HTS assay of choice. This allows you to immediately access a wide variety of antibody pairs in an entirely customizable format. The range of carrier-free pairs on our catalog grows every year, to give you access to the target you need. 

You're not limited to ELISA assays; matched antibody pair kits and carrier-free pairs can be used in other assays adapted to high-throughput scale, such as fluorescent proximity assays (Time-Resolved Fluorescence Energy Transfer [TR-FRET]).   Each pair is based on recombinant monoclonal antibodies for the highest level of batch-to-batch consistency between each of your screening runs. 

Protein standards are essential references and tools used to generate a standard curve and quantify the concentration of the target protein in a sample.

To support your immunoassay development, we offer a growing range of recombinant protein standards complementary with our matched antibody pairs, capture and detector antibodies and SimpleStep ELISA kit range. 

These are the same proteins used as the immunogens to develop our antibody pairs and are available as 10  µg, characterized and validated with SDS-PAGE and sandwich ELISA using the corresponding capture and detector antibodies. 

Browse our protein standards