Biomedical Engineering Reference
In-Depth Information
5.5 BIOMATERIALS PROCESSING TECHNIQUES FOR GUIDING
TISSUE REPAIR AND REGENERATION
5.5.1 Methods to Modify Surface Chemistry (1-D)
The interaction of cells and tissues with biomaterial surfaces is critically important to
promote new tissue deposition and for healthy integration with the surrounding extracellu-
lar matrix. In nature, the surface chemistry of every cell and the extracellular matrix is care-
fully controlled to obtain the desired response. Cell-to-extracellular matrix interactions are
dominated by the interaction of cell-adhesion proteins (ligands) bound to the extracellular
matrix and cell surface receptors (primarily integrins). In medical device applications, it is
important to understand that the biomaterial appears as an extracellular matrix to the cells
and sends signals to the cells interacting with it through similar mechanisms (Figure 5.10).
Thus, the biomaterial surface plays a very important role in determining tissue-biomaterial
interactions, and this concept has governed the development of many new surface modifica-
tion techniques.
Surface of Biomaterial
Surface immobilized
protein ligands
Signal Transduction
Intracellular Signaling
Molecules
Possible Activity from
Cell/Biomaterial
Interaction:
Proliferation
Cytosolic Target
Proteins
Nucleus
Protein synthesis
Gene Regulatory Proteins
Differentiation
(inhibit/up-regulate)
Cell Migration
Apoptosis
FIGURE 5.10
Like the extracellular matrix, a protein-covered biomaterial sends signals to the cell interacting
with it through ligand-receptor mechanisms. Primary cell signal transduction is facilitated through multiple path-
ways, leading to the synthesis of various intracellular signaling molecules. Acting both on the genetic regulatory
proteins in the nucleus and other cytosolic target proteins, the signaling molecules can induce various phenotypic
expressions. Ideally, the biomaterials scientist can engineer the proper surface treatment to elicit the desired
cellular activity.
