Biomedical Engineering Reference
In-Depth Information
(a)
A. Initial contact of the cell
(b)
B. Formation of bonds
between cell surface receptors
and cell adhesion legands
(c)
C. Cytoskeletal reorganisation
with progressive spreading of
cell on material surface
Cell adhesion substrate
Cell adhesion ligands
Cell adhesion receptors
Figure 1.5.
Schematic illustration showing the anatomy of a eukaryotic animal cell (a) and
the fundamental mechanisms involved in biomaterial-cell interaction, established by the
adsorbed proteins (circles, boxes and triangles) with the integrin proteins of a biological
cell (b). [Reproduced from BD Ratner, AS Hoffman, FJ Schoen, JE Lemons, Biomaterials Sci-
ence—An Introduction to Materials in Medicine, 2
nd
edition, Academic Press, New York, 2004.]
and the initial interaction is established through the interaction of cell surface
receptors with adsorbed protein ligands. Such protein-to-protein binding impor-
tantly helps a cell to spread on the material surface.
Subsequent spreading to cover entire implant surface is also facilitated by
cytoskeletal reorganization, as shown schematically in Figure 1.5.
After implantation of a biomaterial, a monolayer of protein molecules gets
absorbed on the material surface within a minute. Subsequently, the transport of
various cell types towards the biomaterial surface occurs and the interaction of
the integrin proteins of cell surface with the absorbed protein of biomaterials
surface is established. The secretion of cell enzymes of various cell type form an
extra cellular matrix (ECM). Depending on cell biomaterial interaction, various
cell types can adhere in a self-organized manner to form a tissue. To this end,
an important event is the formation of the small blood vessels (angiogenesis) as
well as formation of large blood vessels (vasculogenesis) within the newly-formed
tissue layer. Such formation is necessary for the supply of nutrients locally to
various cell types as well as for the removal of waste from ECM.
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