Syracuse Biomaterials Institute, Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States.
Biomacromolecules. 2011 Aug 8;12(8):3066-77. doi: 10.1021/bm2006938. Epub 2011 Jun 24.
In this Article, we studied the enzymatic hydrolytic biodegradation behavior of a novel multiblock thermoplastic polyurethane (TPU) system, which incorporates polyhedral oligomeric silsesquioxane (POSS) into linear biodegradable thermoplastic polyurethanes containing poly(ε-caproactone) (PCL) and polyethylene glycol (PEG) blocks. The biodegradation behavior of POSS-PCL-PEG TPUs was characterized by proton nuclear magnetic resonance spectroscopy ((1)H NMR), differential scanning calorimetry (DSC), tensile tests, scanning electron microscopy (SEM), and wavelength dispersive X-ray spectrometry (WDS) after enduring 22-day accelerated enzymatic hydrolytic degradation tests. POSS incorporation significantly suppressed in vitro enzymatic hydrolytic degradation of PCL-PEG-based multiblock TPUs by a surface passivation mechanism. WDS observations revealed that the covalently bonded POSS moieties developed a near-continuous and robust POSS-layer after initial degradation, which prevented ester bonds of PCL from enzymatic attack, thereby inhibiting further degradation. These striking results provide a new strategy to fabricate the polyester-based biostable thermoplastic polyurethanes (TPUs) of potential use in long-term surgical implants.
在本文中，我们研究了一种新型多嵌段热塑性聚氨酯（TPU）系统的酶解生物降解行为，该系统将笼型倍半硅氧烷（POSS）纳入含有聚（ε-己内酯）（PCL）和聚乙二醇（PEG）嵌段的线性可生物降解热塑性聚氨酯中。通过质子核磁共振波谱（1H NMR）、差示扫描量热法（DSC）、拉伸试验、扫描电子显微镜（SEM）和波长色散 X 射线光谱（WDS）对 POSS-PCL-PEG TPU 的生物降解行为进行了表征，这些测试是在经历 22 天加速酶解降解试验后进行的。POSS 的掺入通过表面钝化机制显著抑制了基于 PCL-PEG 的多嵌段 TPU 的体外酶解降解。WDS 观察表明，在初始降解后，共价键合的 POSS 基团形成了一个近乎连续的坚固的 POSS 层，阻止了 PCL 的酯键受到酶的攻击，从而抑制了进一步的降解。这些显著的结果为制备潜在用于长期手术植入物的聚酯基生物稳定热塑性聚氨酯（TPU）提供了一种新策略。
