“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics
Characterization of Biomaterial Patches as Fetal Surgery Implants 41
based on ASTM specification #D3787-07. After clamping the mesh
specimen between two circular rings, a 2.5 cm diameter ball was
compressed on the specimen at a speed of 300 mm/min until failure
(Fig. 8(b)).^20
Except for the ProLite® Ultra (uncoated PP mesh), INFINIT®
Mesh (uncoated PTFE mesh), and C-QUR® Lite Small and
ULTRAPRO® (meshes with partially absorbable coatings), all others
resisted tearing and displayed tear strengths greater than 20 N. All
meshes had tensile strengths greater than 50 N/cm during ball burst
testing, except the INFINIT® Mesh (uncoated PTFE mesh) and
ULTRAPRO® (PP mesh with absorbable coating). The results indi-
cated that certain meshes must not be used in conditions that require
tensile strength above 50 N/cm, such as in an extremely obese
patient. Also, certain meshes demonstrated strains below the physio-
logical range of approximately 10–30% for the human anterior
abdominal wall,19,20 which can lead to the mesh stretching lesser than
the abdominal wall. This study has the advantage of carrying out ball
burst strength testing, which encompasses the biaxial forces experi-
enced by the mesh in vitro.^20
In the case of fetal implants, ball burst strength tests would per-
fectly simulate the forces encountered by the patch during the growth
process of the fetus. Based on the burst strength test data, the visco-
elastic properties of fetal implants can be programmed. This would
ensure that the growth of the fetus is not hampered by the patch
stiffness, and the mechanical integrity of the implant is sustained over
the complete gestation period.
2.3. Degradation Studies
Material degradation needs to be investigated in detail for surgical
patches, since it can have a deep impact on the biocompatibility and
tissue response. Byproducts released during degradation of polymers
also need to be analyzed, to confirm whether a particular mesh is ideal
for clinical use.^10 Sometimes, mesh fixation leads to damage to adja-
cent tissues, triggering phagocytes and macrophages that degrade
foreign materials before wound healing begins. In the midst of this
