Effect of NaCl concentration on the behavior of stimuli-sensitive microgel in SPR sensor

COLL 254

Anan Jeenanong, nun_infinity@hotmail.com and Haruma Kawaguchi. Department of Chemistry, Kawaguchi-laboratory, Keio university, 3-14-1 Hiyoshi, Yokohama, 223-8522, Japan
Behavior of stimuli-sensitive microgels on SPR (surface plasmon resonance) sensor chip was studied using poly(N-isopropylacrylamide-co-acrylic acid) microgels. The dispersions of microgels with different NaCl concentrations were run over the SPR chip which was covered with a self-assembled monolayer (SAM) having amine functional groups at the top surface. The hydrodynamic size of microgels decreased with increasing salt concentration in dispersion and also on the SPR chip. SPR response of microgels bound to the chip was found to be controlled by the microgel induced change of the mean square electric field amplitude which was a function of the swelling degree and volume of microgels on the chip. The simulated SPR response sufficiently described the effects of physicochemical parameters.