b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”40 Tissue Engineering and Nanotheranostics
the physiological conditions encountered by the mesh, biaxial testing
and in vivo models would provide superior insights into mesh perfor-
mance. It would be interesting to study the effect on fetal patches
during the breathing cycle of the mother. If the breathing cycle of the
mother exerts any kind of pressure before the incision in the placenta
has completely healed, dynamic tests might be of importance.
Deeken and Abdo assessed the physico-mechanical behavior of
surgical meshes used in hernia repair.^20 Nine FDA-approved meshes
were assessed, including four uncoated, one PTFE, one polyester and
three with partially absorbable filaments. Each specimen was made
using a 2.5 cm × 5.1 cm template, thickness was measured using laser
micrometry and density was calculated by dividing specimen mass by
specimen area. Tear resistance testing was established in compliance
with ASTM specification #D2261-07a. A 2.5 cm slit was cut from the
edge to the center of the mesh to create 2 tabs and each tab was
clamped in the upper and lower grips of an Instron machine (Fig. 8(a)).
Out of the 12 mesh specimens considered, six were oriented perpen-
dicular and other six were parallel to longest dimension of the mesh
interstices. Tear strength was computed as the maximum load sus-
tained by the mesh, when the specimen was stretched in tension at
300 mm/min.^20 For ball burst testing, five specimens measuring 9 cm ×
9 cm were prepared and mesh orientation was not taken into account
owing to the biaxial nature of the test.^20 A test fixture was constructed
Fig. 8. Biomechanical test fixtures for (a) tear resistance and (b) burst testing.^20(a) (b)