Carboxymethylated sensor chip

The surface matrix of a carboxymethylated sensor chip CMS (Pharmacia Biosensor, Uppsala, Sweden) was activated by injection of 35 pL of 0.05 M N-hydroxy-succinimide (NHS)/0.2 M N-ethyl-N (dimethylaminopropyl)carbodiimide (EDC). The BIAcore IFC forms four parallel flow cells on the sensor chip. Three of them were derivatized with 40 mM cystamin-dihydrochloride/ethanolamine in the ratios... 

Studies of the interaction of IL-6 and the sIL-6R were monitored by SPR detection using a BIAcore instrument [1] (Pharmacia, Uppsala). Immobilisation of the respective proteins to the carboxymethylated dextran matrix coating the gold sensor chip was performed using the EDC/NHS coupling chemistry as previously described for IL-6 and sIL-6R [3, 7, 8]. Regeneration of the sensor surface for IL-6 and sIL-6R was performed with lOmM HCl for 3 min [8] and 4M MgCl2 in lOmM Tris-HCl buffer, pH 7.4 for 1 min respectively. 

Covalent coupling via amine groups is the standard immobilization procedure [21], which includes three steps. First, the carboxymethyl (CM)-groups on the sensor chip matrix are activated by a mixture of EDC (A-ethyl-A -(3-dimethyl-aminopropyl)-carbodiimide) and NHS (A-hydroxysuccinimide), then covalently bound to free amine groups of the biomolecules, and finally all remaining activated... 

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