Carboxy methylated dextran
CM3 - short dextran
Sensor chip CM3 provides the same functionality as Sensor chip CM5 but has a shorter carboxymethylated dextran matrix. The shorter matrix may be of value in work with large analytes such as cells and virus particles. It may also give reduced non-specific binding in work with serum, and can be valuable in testing the influence of the CM5 dextran matrix on kinetic determinations. Experimental protocols follow the same principles as applied to Sensor chip CM5. Due to the shorter matrix, the immobilization yield will be approximately 30% of that obtained on Sensor chip CM5 under comparable conditions.
CM4 - Low carboxylation
Sensor chip CM4 has a dextran matrix like the Sensor chip CM5 but with a low degree of carboxylation. It provides the same functionality as Sensor chip CM5, but is less negatively charged. The lower degree of carboxylation may be of value for reducing non-specific binding in work with analytes with a high positive charge or crude samples, such as cell culture supernatants and cell homogenates. Sensor chip CM4 may also be useful in kinetic applications where low ligand densities are important. Experimental protocols follow the same principles applied to Sensor chip CM5. Due to the lower degree of carboxylation, the immobilization yield will be approximately 30% of that obtained on Sensor chip CM5 under comparable conditions.
CM5 - standard surface
Sensor chip CM5 is a general-purpose chip for interaction analysis involving all types of biomolecules such as small organic molecules, proteins, lipids, carbohydrates, and nucleic acids. The sensor chip design to allow detailed quantitative studies of these reagents to yield data on e.g. interaction kinetics, affinity, concentration and binding ratios.
The ligand is covalently bound to the sensor chip surface via carboxyl moieties on the dextran. Functional groups on the ligand that can be used for coupling include NH2, SH, CHO and COOH (1).
Sensor chip CM5 is regenerated by selective dissociation of the analyte from the covalently immobilized ligand. Conditions should be chosen to achieve complete dissociation of the analyte without affecting the binding characteristics of the ligand.
CM7 - High carboxylation
Sensor chip CM7 is comparable with the CM5 chip but has a higher density of carboxymethylated dextran covalently attached to the gold surface. In addition, the degree of carboxylation is higher which gives the sensor chip an approximately three times higher immobilization capacity.
Molecules are covalently coupled to the sensor surface via amine, thiol, aldehyde or carboxyl groups. The surface is ideal for applications, which use small molecules and fragments. It is generally less suitable when working with large biomolecular analytes.