CMTEG–modified sensor chips
XanTec’s 2D CMTEG sensor chips are based on an ultra-short, carboxymethylated tetraethyleneglycol (CMTEG) brush grafted onto a hydrophilic adhesion promoter on a gold support. Ligands can be covalently attached via their amine, thiol, or aldehyde groups using established coupling chemistries such as EDC/sulfo-NHS activation, thiol–maleimide coupling, or reductive amination. This enables immobilization of proteins, antibodies, peptides, nucleic acids, carbohydrates, and small molecules.
Protein immobilization capacity is relatively low (typically < 1000 µRIU), while the highly hydrophilic surface provides outstanding resistance to nonspecific binding. In contrast to the chemically related CMPEG surface, CMTEG is not amphiphilic due to its much shorter polyethylene chains. As a result, CMTEG surfaces are particularly useful in experiments challenged by persistent nonspecific interactions, especially those involving strongly positively charged biomolecules or complex sample matrices such as cell culture media.
Key features:
- Very low background binding: Excellent suppression of nonspecific binding, particularly highly cationic biomolecules; well suited for complex sample matrices such as cell culture media.
- Versatile ligand coupling: Supports covalent attachment via amine, thiol, or aldehyde groups using established chemistries (EDC/sulfo-NHS, maleimide, reductive amination).
- Low sensor matrix profile: The planar 2D coating enables reliable kinetic analysis of systems with fast on- and off-rates.
- No polysaccharide backbone: Absence of carbohydrate motifs prevents unwanted interactions with lectins and other carbohydrate-binding biomolecules.
| Product code | CMTEG |
|---|---|
| Base coating | 2D, CM-tetraethyleneglycol (high density) |
| Electrostatic preconcentration capacity [µRIU]2 | < 1000 |
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| Recommended analytes |
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| Intended purpose |
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1 All illustrations are schematic representations and are not drawn to scale; dimensions, densities, and spatial relationships do not reflect actual physical or chemical proportions.
2 Preconcentration capacity determined by injecting 100 µg/mL bovine serum albumin (BSA) in 5 mM sodium acetate pH 5.0, with 1 µRIU corresponding to ≈ 1 RU. Maximum covalent coupling yields depend strongly on the properties of the immobilized protein; under optimal conditions, typical coupling efficiencies span ≈ 20–45% of the respective electrostatic preconcentration capacity.