Civil Engineering Reference
In-Depth Information
Histopathology and immunohistochemistry studies revealed a transient acute inl am-
matory reaction around the patch. At er 90 days, a mild chronic inl ammatory reaction
with foreign-body giant cells was observed. Also, the study found proceeding cellular
organization characterized by i bromuscular cells, production of extracellular matrix
and neoangiogenesis as well as complete neoendothelialization of the patch. h ey con-
cluded that biocompatibility of microbial cellulose is convincing, and the material has,
therefore, potential for use as an alternative patch material in pediatric cardiology.
Bäckdahl
et al.
[109] prepared microbial cellulose-based grat s with 6 mm internal
diameter and clinical trials were carried out to evaluate the performance as cardiovas-
cular grat . In the clinical trial, 4 cm long vascular grat s were placed into circulation as
an aorto-aorto interpositional bypass in the infrarenal aorta of the clinical models and
the grat s were retrieved at er 4 weeks. Figure 16.5 shows the image of microbial cel-
lulose vascular grat which has been retrieved at er 4 weeks. h ere was no leakage and
mechanical rupture was observed on the grat s, an indication that microbial cellulose
tube provides sui cient mechanical properties to be used as vascular grat . Also, there
was no sign of thrombosis when the tube was opened up by cutting longitudinally. h e
internal surface of lumen of microbial cellulose looked very smooth and had a nice
single layer of cells. h e results show that microbial cellulose is a potential candidate as
vascular grat s of the future.
Basnett
et al
. [110] reported novel poly(3-hydroxyoctanoate), P(3HO), and micro-
bial cellulose composites and showed the addition of microbial cellulose has resulted in
properties that are highly desirable for medical applications, including the development
of biodegradable stents. Poly(3-hydroxyoctanoate) is hydrophobic in nature, whereas
microbial cellulose is extremely hydrophilic in nature, hence chemical modii cation
of microbial cellulose is required to achieve compatibility with the poly(3-hydroxyoc-
tanoate) matrix to prepare a homogenous composite. h e composite was prepared by
physical blending of modii ed microbial cellulose microcrystals and poly(3-hydroxyoc-
tanoate) and solvent cast into two-dimensional composite i lms. Young's modulus
and glass transition temperature of the poly(3-hydroxyoctanoate)/microbial cellulose
Figure 16.5
Microbial cellulose grat of 6 mm long implanted as a infrarenal aortic bypass. (Adapted
from Reference [109]).
