Table 2.

Combinations of anchors and spacers that render substrates inert to non-specific biomolecular binding.

Type	Graphic Example	Advantages	Disadvantages	Surface Materials	Examples
Proteins		easy to handle general biocompatible	unspecific to surface material, surface patches exposed, non-specific binding and orientation	relatively general	bovine serum albumin fibrinogen milk proteins
Self-assembled monolayers		applicable to many surface materials receptor exposure good	small substrate defects alter function, low resistance to fouling	Au, Ag, SiO2, TiO2, Al2O3	OEG-thiols OEG-silanes
Surface-grafted polymer brushes		surface chemistry specific grafting grafting from of any spacer mix and match functionality by grafting to	difficult to control surface density, low availability of functional group	Au, Ag, SiO2, TiO2, Al2O3, Fe3O4, Fe2O3	PEG-thiols PEG-silanes PEG-DOPA3 PEG-nitrocatechols
Physisorbed graft copolymer brushes		applicable to many surface materials low defect intensity known density of functional groups	large surface area per macromolecule, low availability of functional group, non-specific surface attachment	Au, Ag, SiO2, TiO2, Nb2O5, Si3N4, Al2O3,	PLL-g-PEG PLL-g-PMOXA Pluronics®
Amphiphilic membranes		cell membrane mimic multivalancy through lateral mobility	cannot be dried, limited to certain surface materials	SiO2, TiO2, ITO, hydrophobic surfaces	Lipids block-co-polymers