Mechanically robust enzymatically degradable shape memory polyurethane urea with a rapid recovery response induced by NIR
Mechanically robust enzymatically degradable shape memory polyurethane urea with a rapid recovery response induced by NIR
复制标题
机械坚固的酶促降解形状记忆聚氨酯脲，具有近红外诱导的快速恢复响应
DOI：
10.1039/d0tb00798f
复制
发表时间：
2020-06-21
影响因子：
7
通讯作者：
Tan, Hong
中科院分区：
文献类型：
--
作者：
Li, Xin;Liu, Wenkai;Tan, Hong
可生物降解的形状记忆聚合物在微创外科手术中具有巨大的应用潜力。本文以胰凝乳蛋白酶为扩链剂，成功地制备了一系列力学性能可调、形状记忆效果优异的形状记忆聚氨酯（SMPU）。采用核磁共振氢谱、拉伸试验、动态力学分析和扫描电镜等手段对PU的化学结构、力学性能、SME和体外降解性能进行了系统的表征。通过增加聚己内酯（PCL）的分子量和硬段含量，获得了模量值为115 MPa的PCL 4000基SMPU，是PCL 2000基样品的3倍。此外，当温度从23摄氏度增加到37摄氏度时，基于PCL 4000的SMPU的模量增加了50%，而基于PCL 2000的SMPU的模量显著降低。此外，基于PCL 4000的SMPU具有良好的形状记忆效应，形状固定率和回复率几乎达到100%。将金纳米棒进一步掺入PU基质中，赋予材料23 s内的快速近红外（NIR）响应以进行形状恢复（NIR波长为808 nm，1.5 W）。结合酶降解性，这些聚氨酯/金纳米棒复合材料显示出巨大的潜力，用于可生物降解的形状记忆扩张支架。
Biodegradable shape memory polymers have great potential for use in minimally invasive surgical procedures. Herein, a series of shape memory polyurethanes (SMPUs) containing a chymotrypsin-inspired chain extender with adjustable mechanical properties and excellent shape memory effect (SME) was prepared successfully. The chemical structure, mechanical properties, SME andin vitrodegradation of the PUs were systematically characterized by proton nuclear magnetic resonance spectroscopy, tensile testing, dynamic mechanical analysis under controlled force mode, and scanning electronic microscopy. By increasing the molecular weight of poly(epsilon-caprolactone) (PCL) and hard segment content, a PCL4000-based SMPU with a modulus value of 115 MPa was obtained, which is three times that of a PCL2000-based sample. Further, the modulus of the PCL4000-based SMPU was increased by 50% while that of the PCL2000-based SMPU was significantly reduced when temperature increased from 23 degrees C to 37 degrees C. In addition, the PCL4000-based SMPU exhibited excellent SME with the shape fixity ratio and recovery ratio almost reaching 100%. Gold nanorods were further incorporated into the PU matrix, endowing the materials with a fast near-infrared (NIR) response in 23 s for shape recovery (NIR wavelength of 808 nm, 1.5 W). Combined with enzymatic degradability, these PU/gold-nanorod composites exhibit great potential to be used in biodegradable shape memory expanding stents.