Biomedical Engineering Reference
In-Depth Information
local gradients of growth factors and cytokines within tissues, as
convection and diffusion interplay with protein secretion and
uptake.Fromthisitisobviousthattissuebehaviorisgreatlyaffected
by the mechanical parameters of the tissueenvironment.
The above-mentioned biomechanical and fluidic effects are
important considerations when engineering scaffolds for epithelial
tissue. The scaffold should have an optimum stiffness for the target
tissue type and allow sheetlike assemblies of cells that interact in a
3D fashion and whosesurfaces are accessible by fluid flow.
24.3 Engineering an Extracellular Microenvironment for
Epithelial Cells
24.3.1
The State of Art
Polymeric matrices have been developed as cell support in various
epithelial tissue engineering covering transplantation, extracorpo-
realdevices,and
invitro
modelsforpathophysiologicalresearchand
drug screening. They are composed of synthetic, natural, or hybrid
materials. The matrices developed so far are either in 2D or 3D
configurations, in various forms, including membranes, fibers,
microcarriers, microcapsules, hydrogels, and macroporous scaf-
folds. Generally speaking, they have been designed based on the fol-
lowing criteria:
(a) Controlled cell-matrix interactions
(b) Controlled homotypic and heterotypic cell-cell contacts
(c) Retentionofdifferentiatedphenotypesandfunctionsbythe
cells and possiblyproliferation
(d) Biocompatibility and biodegradability for implantation
applications
(e) Biomechanical integrity to the targeted tissues/organs
(f) E
cient delivery of nutrients and oxygen and removal of
metabolite waste
24.3.1.1 2D plastic substrata
The monolayer culture of epithelial cells onto flat substrata
remains one common approach in epithelial tissue engineering,
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