Kratz Karl, Habermann Ronny, Becker Tino, Richau Klaus, Lendlein Andreas
Center for Biomaterial Development and Berlin-Brandenburg Center for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow, Germany.
Int J Artif Organs. 2011 Feb;34(2):225-30. doi: 10.5301/ijao.2011.6404.
Multifunctional polymer-based biomaterials, which combine degradability and shape-memory capability, are promising candidate materials for the realization of active self-anchoring implants. In this work we explored the shape-memory capability as well as the hydrolytic and enzymatic in vitro degradation behavior of electro-spun scaffolds prepared from a multiblock copolymer, containing hydrolytically degradable poly(p-dioxanone) (PPDO) and poly(e-caprolactone) (PCL) segments, which we have named PDC. Electro-spun PDC scaffolds with an average deposit thickness of 80 ± 20 µm and a porosity in the range from 70% to 80% were prepared, where the single fiber diameter was around 3 µm. Excellent shape-memory properties were achieved with high recovery rate (Rr) values in the range of Rr = 92% to 98% and a recovery stress of smax = 4.6 MPa to 5.0 MPa. The switching temperature (Tsw) and the characteristic temperature obtained under constant strain recovery conditions (Ts,max) were found in the range from 32 °C to 35 °C, which was close to the melting temperature (Tm,PCL) associated to the poly(e-caprolactone) domains. A linear mass loss was observed in both hydrolytic and enzymatic degradation experiments. The mass loss was substantially accelerated, in enzymatic degradation when Pseudomonas cepacia lipase was added, which was reported to accelerate the degradation of PCL. During hydrolytic degradation a continuous decrease in elongation at break (eB) from eB = 800% to 15% was observed in a time period of 92 days, while in enzymatic degradation experiments a complete mechanical failure was obtained after 4 days.
兼具降解性和形状记忆功能的多功能聚合物基生物材料，是实现主动自锚定植入物的理想候选材料。在本研究中，我们探究了由多嵌段共聚物制备的电纺支架的形状记忆性能以及体外水解和酶解降解行为，该多嵌段共聚物包含可水解降解的聚对二氧环己酮（PPDO）和聚己内酯（PCL）链段，我们将其命名为PDC。制备了平均沉积厚度为80±20μm、孔隙率在70%至80%范围内的电纺PDC支架，其中单纤维直径约为3μm。实现了优异的形状记忆性能，恢复率（Rr）值在92%至98%范围内，恢复应力smax为4.6MPa至5.0MPa。在32℃至35℃范围内发现了转变温度（Tsw）和在恒定应变恢复条件下获得的特征温度（Ts,max），这与聚己内酯域相关的熔点（Tm,PCL）接近。在水解和酶解降解实验中均观察到质量线性损失。当添加洋葱伯克霍尔德菌脂肪酶时，酶解降解中的质量损失显著加速，据报道该酶可加速PCL的降解。在水解降解过程中，在92天的时间段内观察到断裂伸长率（eB）从eB = 800%持续下降至15%，而在酶解降解实验中，4天后出现了完全的机械失效。
