Forum :: Negative curves


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This forum is intended for questions about kinetics, Surface Plasmon Resonance and the instruments related to these techniques.

TOPIC: Negative curves

Negative curves 05 Jul 2017 10:32 #1

We are using ProteOn XPR36 instrument and performed experiment spot wise, We observed negative signal in Test spot and positive signal in reference spot. What shall we do get rid of this issue?

Negative curves 05 Jul 2017 20:16 #2

Hi Vini,
Welcome to the forum.

The most common cause of NSB is electrostatic attraction of a positively charged analyte or other component to the negatively charged binding layer. Molecules that naturally bind polysaccharides might exhibit NSB to the alginate-containing binding layer, such as lectins. It can be difficult to identify the type of NSB. A deactivation of the reference spots can lower NSB.

What you can try is to adjust the flow buffer by adding more salt (200 mM NaCl), more detergent (0.02% Tween 20) or a non-related protein such as BSA to block all non-specific interaction sites.

Also check: www.sprpages.nl/experiments/troubleshooting

In addition, check the raw data if it is really NSB and not a processing error during the curve fitting procedure.

kind regards
Arnoud
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