Relationship between interfacial forces measured by colloid-probe atomic force microscopy and protein resistance of poly(ethylene glycol)-grafted poly(L-lysine) adlayers on niobia surfaces.

摘要: Adsorbed layers of “comb-type” copolymers consisting PEG chains grafted onto a poly(l-lysine) (PLL) backbone on niobium oxide substrates were studied by colloid-probe AFM in order to characterize the interfacial forces associated with coatings varying architectures (PEG/PLL ratios and chain lengths) their relevance protein resistance. The steric electrostatic measured varied substantially architecture PLL-g-PEG copolymers. Varying ionic strength buffer solutions enabled discrimination between steric−entropic contributions net force. For high grafting densities component was most prominent, but at low strengths densities, repulsive surface force also observed; its origin assigned niobia charges beneath copolymer, as insufficient protonated amine groups PLL available for compensation charges. lower ...