Table 5.

Commonly used affinity tags for surface modifications

Peptide	Surface modifications
RGD-containing peptide	Engineering growing tissues [370] Ligand density characterization of peptide-modified biomaterials [371] Biomimetic peptides [359, 372] The effect of peptide surface density on mineralization of a matrix deposited by osteogenic cells [359, 360] Enhancement of the growth of human endothelial cells by surface roughness at nanometer scale [361] Adhesion of α5β1 receptors to biomimetic substrates constructed from peptide amphiphiles [349] Biomimetic peptide surfaces that regulate adhesion, spreading, cytoskeletal organization, and mineralization of the matrix deposited by osteoblast-like cells [359, 360]
RGD-linked polymers	RGD-peptide-modified poly(lactic acid-co-lysine) [354] Acrylic terpolymers with RGD peptides [356] Diblock copolymers modified with cyclic RGD peptides [355] Polyurethanes [357] Synthetic hydrogels [350, 363, 370] Immobilized RGD peptides on surface-grafted dextran [351] Collagen by covalent grafting with RGD peptides [352] Hyaluronan hydrogel [350] RGD-grafted poly-l-lysine-graft-(polyethylene glycol) copolymers block [353] Neurite outgrowth on well-characterized surfaces [353, 358]
QQKFQFQFEQQ	Enzymatic modification of self-assembled peptide structures with tissue transglutaminase [363] Transglutaminase-mediated gelatin matrix [362]
GHK	Dermal wound healing in rats [12]
KNEED	Cell-binding peptide sequence (III domain of fibronectin) [9]
IKVAV	Neuronal cell attachment [10]
YIGSR	Endothelialization [8] Neuronal cell attachment [10] Immobilization of laminin peptide in molecularly aligned chitosan by covalent bonding [11]