Zwitterion siloxane to passivate silica against nonspecific protein adsorption

Passivating surfaces against protein adsorption is important for many biotechnological applications. Current approaches have been exploiting the use of zwitterions instead of poly(ethylene glycol) (PEG). Commonly used zwitterions are polymeric and are grafted onto surfaces using specialized polymerization techniques. Here we describe the synthesis of a monomeric zwitterion siloxane and its covalent attachment to silica surfaces (nanoparticle and planar) in a one-pot one-step aqueous method requiring no catalyst.