AqT® Biotin Antibody Labeling Kit (Surface Amines)

Product Description

AqT^® Antibody Biotinylation kit is a proprietary biotinylation kit developed at CellMosaic^® for obtaining high quality, highly biotinylated antibodies with minimal or no aggregation.

AqueaTether® (AqT®) linkers are proprietary biomaterials developed at CellMosaic for labeling and conjugating biomolecules with highly hydrophobic small molecules, improving bioconjugate performance in downstream applications. For example, biotin is poorly water-soluble and prone to aggregation; incorporation of the AqT® linker enhances its solubility, enabling labeling with minimal or no organic solvent. The linker’s hydroxyl groups form hydrogen-bond networks with surrounding water, creating a stabilizing microenvironment that reduces biotin–biotin interactions and prevents aggregation or precipitation over time. This allows antibodies to be labeled with high levels of AqT®-biotin without altering their properties, while potentially improving stability against enzymatic degradation and preserving activity. The AqT® Biotin Antibody Labeling Kit (Surface Amines) leverages this technology to produce high-quality, low-aggregation conjugates using a super-hydrophilic, water-soluble, charge-neutral AqT® linker that also minimizes non-specific interactions with proteins and surfaces.

For a detailed description of the AqT® technologies, please see our technology section.

This kit is designed to biotinylate antibodies using AqT® biotin acid via surface amines on the antibody; the user supplies the antibody. The kit includes AqT® biotin acid, which is activated within 15 minutes and then coupled directly to the antibody in a single step. The labeled product is subsequently purified to remove any unreacted AqT® biotin acid. A quick 10-minute biotin assay (reagent and protocol) is also included to determine the biotinylation level immediately after labeling. 

The kit is available in multiple configurations for labeling antibodies (0.1-3 mg) with either one (x1) or three (x3) antibody samples. 

If you have any other customization needs, please provide the details above.

Requirement for Antibody 

1. MW: ≥ 100 KDa (if MW is lower, please use an alternative kit)
2. Preferably >90% pure by gel electrophoresis
3. Total amount: 0.1-3 mg of protein content as measured by UV. 

CM86144 and Its Biotinylated Product Compared to Other Commercial Antibody Biotinylation Kits

Labeling Chemistry

Protocol

Schematic workflow diagram for preparing AqT® biotinylated antibody within 2 hours, starting with 3 mg of IgG. (Reagent volume will vary if the amount of IgG is less than 3 mg).

Example Data

The figures below show several examples of AqT® biotinylated antibodies (human IgG1) compared with conventionally biotinylated antibodies. The extent of labeling and the heterogeneity of the labeled antibodies were assessed by hydrophobic interaction chromatography (HIC)-HPLC (Figure 1). Apparent molecular weight and aggregation were evaluated by size-exclusion chromatography (SEC)-HPLC (Figure 2).

Figure 1: Comparison of the hydrophilicity and heterogeneity of AqT® biotin–labeled antibodies versus conventionally biotinylated antibodies (HIC-HPLC profile). Conventionally biotinylated antibodies are highly heterogeneous and show an ~1.5-minute increase in retention time. In contrast, AqT biotinylated antibodies show only a slight increase in hydrophobicity (~0.15 minutes). Even at high labeling levels, additional biotinylation does not further increase hydrophobicity. AqT biotinylated antibodies also exhibit minimal heterogeneity, with only a slight increase in peak width compared with the unlabeled antibody.

Figure 2: Comparison of the apparent molecular weight (hydrodynamic volume) of AqT® biotin–labeled antibodies versus conventionally biotinylated antibodies (SEC-HPLC profile). Conventionally biotinylated antibodies often show a noticeable increase in apparent molecular weight due to an increased hydrodynamic volume driven by the hydrophobicity of the label. In contrast, AqT biotinylated antibodies show little to no shift in apparent molecular weight and maintain a hydrodynamic volume similar to the native antibody.