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Choice of sensor surface

The choice of sensor surface is dictated by the nature and demands of the application, although there is considerable flexibility in the choice for most applications. General guidelines are given here:

• For general purpose applications where the ligand or capturing molecule is immobilized by standard covalent techniques, Sensor Chip CM5 is the first choice.
• An easy way to attach non-tagged proteins is to biotinylate the protein and use it together with the Biotin CAPture Kit. This kit contains Sensor Chip CAP, Biotin CAPture Reagent and a preoptimized regeneration solution. Using this method requires minimal assay development and optimization.
• Applications that show significant levels of non-specific binding of positively charged molecules may benefit from Sensor Chip CM4, with a lower degree of carboxymethylation and thus a reduced net charge. With plasma or serum samples, however, the reverse may be true: Sensor Chip CM5 has been observed to give lower non-specific binding than CM4 with these samples. Bear in mind that the immobilization capacity of Sensor Chip CM4 is lower than that of CM5.
• Kinetic measurements are best performed with the lowest manageable immobilization level. The reduced capacity of Sensor Chip CM4 and Sensor Chip CM3 can help to keep immobilization levels low.
• The shorter dextran matrix on Sensor Chip CM3 can be an advantage in experiments involving large molecular aggregates, virus particles and whole cells.
• If interference from the dextran matrix itself is suspected, Sensor Chip C1 offers a low-capacity surface with no dextran matrix.
• Sensor Chip SA and Sensor Chip NTA provide ready-to-use surfaces for capture of biotinylated ligands and his-tagged ligands respectively.
• Lipid monolayers can be studied on Sensor Chip HPA. Immobilized liposomes and supported lipid bilayers can be formed using a variety of techniques on Sensor Chip L1.
• Customized surfaces for surface interaction studies can be prepared on Sensor Chip Au and on the chips included in SIA Kit Au. These products are not generally suitable for use directly in biomolecular interaction studies since proteins show a strong tendency to adsorb to and denature on the unmodified gold surface.

A guide on when to choose direct immobilization or capture approach for your SPR assay is availble for download on https://info.cytivalifesciences.com/rs/614-VFU-334/images/How-to-choose-a-suitable-attachment-approach-for-your-ligand.pdf

See also

List of help files