Nanoparticulate cell culture surface

A cell culture article comprising:

• a substrate having nanoparticles (NP) on the substrate surface, wherein the nanoparticles comprise:
• a polymer of formula (I)
• having at least one of:
• a metal-ion chelating group (x), an ionizable group (y), and a surface substantive group (z),
• where
• R is hydrogen or a substituted or unsubstituted, linear or branched, monovalent hydrocarbyl moiety having from 1 to 6 carbon atoms;
• R′ is a substituted or unsubstituted, linear or branched, divalent hydrocarbyl moiety resulting from copolymerization of an unsaturated monomer having from 2 to 18 carbon atoms with maleic anhydride;
• R″ is a substituted or unsubstituted, linear or branched, divalent hydrocarbyl moiety having from 1 to 20 carbon atoms;
• S comprises at least one point of attachment to the substrate;
• W comprises at least one bi-dentate group;
• X is an —NH—, —NR—, or O;
• the mole ratio of x:(y+z) groups is from about 2:8 to about 8:2;
• and the nanoparticles have a diameter of from about 10 to about 100 nanometers.