A vesicle capture sensor chip for kinetic analysis of interactions with membrane-bound receptors

A novel sensor chip for use in surface plasmon resonance (SPR) biosensors has been developed to capture vesicles which may contain membrane-bound receptors. Sulforhodamine-containing vesicles were shown by fluorescence microscopy to be immobilized intact on the sensor chip. Binding of cholera toxin to captured vesicles containing ganglioside GM(1) was demonstrated using SPR, and the derived kinetic and affinity constants were similar to literature values. Biotinylated vesicles captured on the sensor chip were used to bind streptavidin and then biotinylated ss-DNA. The hybridization of complementary ss-DNA to the immobilized ss-DNA was then analyzed using SPR. The values obtained were similar to those obtained for an identical interaction analyzed using a commercially available streptavidin-containing sensor chip. Binding of vancomycin-group antibiotics to captured vesicles containing a bacterial cell wall mucopeptide analogue was demonstrated. No binding of the bacterial endotoxin Cry1A(c) to captured vesicles containing its cell surface receptor could be demonstrated.