Address for correspondence: Donald P. Bottaro, EntreMed, Inc., 9640 Medical Center Drive, Rockville, MD 20850. Voice: 240-864-2777; fax: 240-864-2601.
donb{at}entremed.com
Ann. N.Y. Acad. Sci. 961: 143-153 (2002).
Biological tissues and organs consist of specialized living
cells arrayed within a complex structural and functional framework
known generally as the extracellular matrix (ECM). The great
diversity observed in the morphology and composition of the
ECM contributes enormously to the properties and function of
each organ and tissue. For example, the ECM contributes to the
rigidity and tensile strength of bone, the resilience of cartilage,
the flexibility and hydrostatic strength of blood vessels, and
the elasticity of skin. The ECM is also important during growth,
development, and wound repair: its own dynamic composition acts
as a reservoir for soluble signaling molecules and mediates
signals from other sources to migrating, proliferating, and
differentiating cells. Artificial three-dimensional substitutes
for ECM, called tissue scaffolds, may consist of natural or
synthetic polymers or a combination of both. Scaffolds have
been used successfully alone and in combination with cells and
soluble factors to induce tissue formation or promote tissue
repair. Appropriate numbers of properly functioning living cells
are central to many tissue-engineering strategies, and significant
efforts have been made to identify and propagate pluripotent
stem cells and lineage-restricted progenitor cells. The study
of these and other living cells in artificial microenvironments,
in turn, has led to the identifcation of signaling events important
for their controlled proliferation, proper differentiation,
and optimal function.
