FABRICATION OF TISSUE ENGINEERING SCAFFOLDS BY ELECTROSPINNING TECHNIQUES - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 228

thenativearteryiscomprisedofthreedistinctlayers(intima,media,
andadventitia),Boland et al .madeanextremelydauntingattemptto
create a biomimicking vascular graft with a three-layered vascular
construction. A collagen type I and elastin solution (w/w, 80/20) at
a concentration of 0.083 g/mL in 1,1,1,3,3,3-hexafluoro-2-propanol
(HFP) was electrospun onto a 4 mm internal diameter (ID) tubular
mandrelandsubsequentlyseededwithbothfibroblastsandsmooth
muscle cells. Another tubular scaffold, this time of 2 mm ID, was
created with a collagen type I and elastin solution (w/w, 30/70)
and inserted into the 4 mm ID scaffold. The lumen was filled with a
smoothmusclecellsuspensionandculturedfor3days.Finally,asus-
pension of human umbilical vascular endothelial cells was injected
intothelumen,andtheentireconstructwasculturedfor2additional
days.Histologicalexaminationrevealedthatthescaffoldwasathree-
layered construct withcomplete cellular infiltration. 37
Considering some specific requirements of tubular scaffolds in
tissue engineering applications, such as the variation in anatomic
location and biological environment, it is also important to design
and control microscopic and macroscopic 3D structures of tubes
to create desired cellular responses. 38 A novel static method of
fabricating 3D fibrous tubes composed of ultrafine electrospun
fibers was recently achieved. 39 By using this unique technique,
micro and macro single tubes with multiple micropatterns, multi-
pleinterconnectedtubes,andmanytubeswiththesameordifferent
sizes, shapes, structures, and patterns can be prepared synchro-
nously (Fig. 11.5). It is expected that electrospinning with the sta-
tic collecting method using 3D collectors with specifically designed
patterns and configurations has great potential for fabrication of
fibrous tubes with controllable architectures and 3D configura-
tions, which may be attractive in many biomedical and industrial
applications.
These results indicate that electrospun tubes, without an addi-
tional biological coating or drug-loading treatment, are promising
scaffoldsforfunctionalnervousregeneration.Electrospuntubescan
be knitted in meshes and various frames, depending on the cytoar-
chitecture of the tissue to be regenerated. Moreover, these guidance
conduits can be loaded with various fillers, such as collagen, fibrin,
or self-assembling peptide gels, or with cytokines and seeded with