Biomedical Engineering Reference
In-Depth Information
trol of integrin binding specificity could be exploited to precisely engineer
cell-material biomolecular interactions to activate specific signaling pathways
and differentiation programs.
3
Biomimetic Interfaces Promoting Cell Adhesion
3.1
Biological Motifs as Targets for Biomaterial Applications
Significant advances in the engineering of biomaterials that elicit specific
cellular responses have been attained over the last decade by exploiting
biomolecular recognition. These biomimetic engineering approaches focus on
integrating recognition and structural motifs from biological macromolecules
with synthetic and natural substrates to generate materials with biofunc-
tionality [14, 50]. These strategies represent a paradigm shift in biomaterials
development from conventional approaches dealing with purely synthetic or
natural materials to hybrid materials incorporating biological motifs. These
biomimetic strategies provide promising schemes for the development of novel
bioactive substrates for enhanced tissue replacement and regeneration. Be-
cause of the central roles that ECMs play in tissue morphogenesis, homeosta-
sis, and repair, these natural scaffolds provide several attractive characteristics
worthy of copying or mimicking to convey functionality for molecular control
of cell function, tissue structure, and regeneration. Four ECM “themes” have
been targeted: (i) motifs to promote cell adhesion, (ii) growth factor binding
sites that control presentation and delivery, (iii) protease-sensitive sequences
for controlled degradation, and (iv) structural motifs to convey mechanical
properties. This review focuses on bioadhesive materials; excellent reviews on
other biomimetic strategies can be found elsewhere [14].
3.2
First-Generation Biomimetic Adhesive Supports: Short Oligopeptides
Following the identification of adhesion motifs from ECM components,
such as the RGD sequence in FN and the tyrosine-isoleucine-glycine-serine-
arginine (YIGSR) oligopeptide in LN, short bioadhesive oligopeptides have
been tethered/immobilized onto synthetic or natural substrates and three-
dimensional scaffolds to produce biofunctional materials that bind integrin
receptors and promote adhesion in various cell types [51-53] (Fig. 4). Non-
fouling supports, such as PEG, polyacrylamide, and alginate, are often used
to reduce nonspecific protein adsorption and present the bioadhesive motif
within a nonadhesive background. Tethering of these short bioactive se-
quences promotes in vitro cellular activities, including adhesion, migration,
