STRATEGIES TO ENGINEER ELECTROSPUN SCAFFOLD ARCHITECTURE AND FUNCTION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 292

attachment, spreading, and function 10 —have motivated efforts to
apply this technology to cell- and tissue-contactingmedical devices.
Despite this early promise, electrospun materials have not yet
been clinically approved for medical applications. Ironically, their
limitations as medical devices may be linked to their advantages
as nanomaterials. Because they are comprised of submicron fibers,
electrospun meshes are extremely soft, their tensile strength is dic-
tatedbythestrengthoffibercross-links,theporesinmeshesareon
the order of a few microns, and the rate of mesh formation is on the
order of several microns (in thickness) per minute. Consequently,
electrospinning—as a technology—must be married to other tech-
nologies to achieve scaffold architectures that are tailored toward
specific tissue applications.
This chapter examines some of the strategies that have been
described in the literature to tailor the architecture of elec-
trospun scaffolds—at the nanometer-, micron-, and millimeter-
length scales—for specific applications. At the length scale of tens
of nanometers to a few microns, fiber features create surface
topographies that affect the attachment, orientation, and function
of anchorage-dependent mammalian cells. At the length scale of
microns, the porosity of the electrospun scaffolds affects the abil-
ity for cells to migrate, deposit an extracellular matrix, and self-
assembleintotissue-likestructures.Finally,atthemillimeter-length
scale, the electrospun scaffold must exhibit the shape—and ide-
ally the mechanical properties—of the tissue it is designed to
regenerate.
The organization of this review is built around key features of
electrospun meshes at the nanometer-, micron-, and millimeter-
length scales and highlights strategies that have been employed for
tissue engineering applications. It concludes with considerations of
the mechanical properties of electrospun structures and how they
depend on the scaffoldarchitecture.
15.2 Design of Fiber Topography to Affect Cell Function
Viability, proliferation, and phenotypic behavior of anchorage-
dependent cells depend heavily on the micron-scale physical