Biomedical Engineering Reference
In-Depth Information
wasmuchhigher,andthecellsgrewmorequicklyinthehybridmesh
thaninthePLGAmesh.ThefibroblastsinthePLGAmeshgrewfrom
theperipheralPLGAfiberstowardthecentersoftheopenings,while
those in the hybrid mesh also grew from the collagen microsponges
in the openings of the mesh, resulting in more homogenous growth.
Theproliferatedcellsandsecretedextracellularmatricesweremore
uniformly distributed in the hybrid mesh than in the PLGA mesh.
Histological staining of in vitro -cultured fibroblast/mesh implants
indicated that the fibroblasts were distributed throughout the
hybrid mesh and formed a uniform layer of dermal tissue having
almost the same thickness as that of the hybrid mesh. However, the
tissue formed in the PLGA mesh was thick adjacent to the PLGA
fibers and thin in the centers of the openings. The results indi-
catethattheweblikecollagenmicrospongesformedintheopenings
of the PLGA knitted mesh increased the e ciency of cell seeding,
improved cell distribution, and therefore facilitated rapid formation
of dermal tissue having a uniformthickness.
Application of the PLGA-collagen hybrid mesh for the regenera-
tionofvesseltissuehasbeenattemptedbyusingthehybridmeshto
patch the canine pulmonary artery trunk. 19 Hybrid meshes with or
withoutautologousvesselcellularizationwereimplanted. Aftertwo
and six months' implantation, histological and biochemical exam-
ination showed that there was no thrombus formation in either
groupandthehybridmeshwasalmostcompletelyabsorbedinboth
groups. Formation of an endothelial cell monolayer, a parallel align-
ment of smooth muscle cells, and a reconstructed vessel wall with
elastin and collagen fibers was confirmed. At six months, the cellu-
lar and extracellular components in the hybrid mesh had increased
to levels similar to those in native tissue. The hybrid mesh might be
useful for in situ cellularization and the regeneration of autologous
tissue in cardiovascular surgery.
22.4 PLLA-Collagen Hybrid Braid
A hybrid scaffold of a PLLA braid and a collagen sponge has
been fabricated for ligament regeneration by forming collagen
microsponges in the interstices of a PLLA braid (Fig. 22.6). 20 The
 
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