CMPG–modified sensor chips
XanTec’s CMPG sensor chips are based on a short, dendritic carboxymethylated polyglycerol (CMPG) 2D sensor matrix grafted onto a hydrophilic adhesion promoter on a gold support. Ligands can be covalently attached via their amine, thiol, or aldehyde groups using standard coupling chemistries such as EDC/NHS activation, thiol–maleimide conjugation, or reductive amination. This enables immobilization of proteins, antibodies, peptides, nucleic acids, and small molecules.
Although the protein immobilization capacity is relatively low (typically ≈ 1,000–2,000 µRIU), the highly hydrophilic, dendritic polymer architecture provides outstanding resistance to nonspecific binding. CMPG surfaces are therefore particularly well suited for 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 of highly cationic biomolecules; well suited for complex sample matrices such as cell culture media.
- Versatile ligand coupling: Supports covalent attachment through amine, thiol, or aldehyde groups using established chemistries (EDC/NHS, maleimide, reductive amination).
- Low sensor matrix profile: The planar 2D coating enables reliable kinetic analysis of systems with fast association and dissociation rates.
- No polysaccharide backbone: Absence of carbohydrate motifs prevents unwanted interactions with lectins or carbohydrate-binding proteins.
| Product code | CMPG |
|---|---|
| Base coating | 2D, carboxymethylated polyglycerol (high density) |
| Electrostatic preconcentration capacity [µRIU]2 | ≈ 2,000 |
| Recommended ligands |
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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 BSA in 5 mM sodium acetate pH 5.0, with 1 µRIU corresponding approximately to 1 RU. Maximum covalent coupling yields depend strongly on ligand properties and typically range from approximately 20–45% of the respective electrostatic preconcentration capacity.