Construction of pegylated multilayer architectures via (strept)avidin/biotin interactions

Pegylated multilayer architectures were fabricated as films on planar substrates, as shells on colloidal particles, or as free-standing hollow capsules using layer-by-layer (LbL) self-assembly of biotinylated poly-l-lysine (PLL) and (strept)avidin. Poly(ethylene glycol) (PEG) was incorporated into the multilayer architectures by assembly with biotin-derivatized poly(l-lysine)-g-poly(ethylene glycol)(PPB). Stepwise growth of multilayers was followed by UV–vis spectroscopy and the formation of core–shells and hollow capsules characterized by means of confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Both absorbance and TEM data suggest that approximately two layers of FITC–avidin were adsorbed with each surface deposition. In contrast, use of unmodified PLL did not lead to formation of multilayer coatings, confirming that (strept)avidin–biotin interactions were responsible for film growth even in the presence of electrostatic repulsive forces between PLL and avidin and the steric hindrance of associated PEG chains. This technique provides new opportunities for the generation of robust films with tailored interfacial binding and transport properties.