“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics
Characterization of Biomaterial Patches as Fetal Surgery Implants 37Another technique to interpret mechanical properties and anisot-
ropy was reported by Pott and Schwarz.^14 Six different meshes were
assessed in view of longitudinal and transverse directions through
uniaxial tensile tests carried out on a ZwickTM 020 universal testing
machine, to compute maximum loads using force-displacement
data.^14 The meshes studied were Dynamesh-Ipom® (PVDF), Parietene®
(PP), Prolene® (PP), Surgipro Pro® (PP), Ultrapro Mesh® (absorbable
polyglecaprone-25 and non-absorbable PP filaments), and Vicryl®
(resorbable polyglactin filaments). A student’s t-test with a confidence
level of 95% was used for intramaterial comparisons (longitudinal vs.
transverse), whereas ANOVA variance analysis with significant
differences for p < 0.001 was employed for intermaterial comparison
of different mesh types (SPSS 18.0).^14
For tensile testing, a dogbone-shaped die (ISO 527-1) was used
to cut samples in longitudinal (warp) and orthogonal (weft) direc-
tions. Prior to testing, the specimens were immersed in isotonic saline
for 30 min.^14 Test conditions included a strain rate of 50 mm/min
and were ended when recorded load fell below 90% of the maximum
load. The test results of maximum load were compared to human data
pertaining to maximum forces in the abdominal wall (Fig. 6).14–17
Fig. 5. (a) Failure of Prolene® samples cut in coursewise (90°) direction; (b) stress vs.
strain curves for failure tests on Prolene® mesh.^13
20 Stress vs. Strain curve of Prolene mesh in the 0º, 45º and 90º directions
18
16
14
12
10
8
6
4
2(^00) 0.2 0. 40 .6 0.8
Strain
Stress (MPa)
(b)(a)
11 .2 1. 41 .6
0º
45º
90º