Biomedical Engineering Reference
In-Depth Information
Fig. 2
Integrins mediate cellular interactions with biomaterials by binding to adhesive ex-
tracellular ligands that can be (i) adsorbed from solution, (ii) deposited onto the surface
by cells, and/or (iii) engineered at the interface (e.g., bioadhesive motifs such as RGD
incorporated onto synthetic supports). Adapted from [53]
with integrin function on a particular substrate. Finally, multiple integrins are
typically involved in a particular cellular response. For example, initial mono-
cyte adhesion to biomaterials is mediated primarily by
β
2
integrin, while both
β
2
integrins are involved in macrophage adhesion and fusion into
foreign-body giant cells [30].
1
and
β
2
Surfaces Controlling Protein Adsorption and Activity
The chemical and topographical characteristics of surfaces have profound
effects on cellular, tissue, and host responses to synthetic materials [11,
31]. Consequently, surface modifications of chemistry and roughness have
been introduced to improve performance in virtually all materials used in
biotechnological [e.g., tissue culture and enzyme-linked immunosorbent as-
say (ELISA) plates, gene and protein array chips, bioseparation and biopro-
cess matrices] and biomedical (e.g., vascular grafts, orthopedic and dental
implants, biosensors, catheters) applications. This review focuses on inter-
faces controlling cell-biomaterial adhesive interactions via manipulations of
material surface chemistry to modulate protein adsorption and activity.
2.1
Protein Adsorption in Cell-Biomaterial Interactions
Protein adsorption onto synthetic surfaces plays central roles in numerous
biomedical and biotechnological applications. Adsorption of blood compo-
nents onto material surfaces triggers coagulation and complent activation as
well as providing adhesive ligands mediating inflammatory responses to im-
planted devices. As discussed previously, cell adhesion to synthetic surfaces,
including tissue-culture supports, tissue-engineering scaffolds, and affinity
chromatography media, often involves binding of cellular receptors to pro-
