Page 129 - Tailoring Electrospinning Techniques for Regenerative Medicine - Marc Simonet

Table 6.1
PCL
PCLγ-S PCL2kU4Un PCL2kU4Un γ -S
3.2±0.1 3.7±0.3 19.6±2.3 19.6±2.2
FROM A POLYMER TOWARDS AN IN-SITU TISSUE ENGINEERED HEART VALVE
Overview on the mechanical properties and molecular weight of PCL and PCL2kU4Un prior and a er γ-sterilization (-S). ** = p<0.01
Young’s Modulus [MPa]
9.8±0.7 10.2±1.2 0.73±0.01 0.81±0.02
Yield strength [MPa]
0.35±0.02 0.35±0.02 0.14±0.02 0.15±0.02
Elongation at yield [%]
Tensile strength [MPa]
1.13±0.09 0.99±0.05 1.66±0.07 1.42±0.11
Elongation at UTS Mw [%] [kDa]
343±53** 103 235±6** 79 966±85 76 880±140 60
supposed to withstand repeated strains better than PCL. γ-Sterilization had no significant e ect on these mechanical properties. The sterilization had most influence on elongation at ultimate tensile strength (UTS). For PCL sca olds the elongation at UTS drops significantly from 343±53% to 235±6% a er sterilization (p< 0.01). In comparison, γ-sterilization did not significantly alter the elongation at UTS of the PCL2kU4Un sca olds.
The durability of electrospun materials was tested with a fatigue test at 10% elongation for up to 3 million cycles. The 10% elongation was adapted from local valve strain deformation calculated by Kortsmit et al.23 To reduce the measuring time, we assessed the di erence in fatigue behavior between the test frequencies of 10 Hz vs. the more physiological 2 Hz.
Figure 6.2 Comparison of the measured fatigue resistance: (a) stress response at 10% strain at cycle 10, 100 and 100 for the non-sterile and sterilized PCL and PCL2kU4Un sca olds, including the values measured with the 2 Hz protocol for the PCL sca olds (b) the amount of cycles, where the stress response at 10% strain dropped below 10% of its original value.
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