Ultrasound-Modulated Shape Memory and Payload Release Effects in a Biodegradable Cylindrical Rod Made of Chitosan-Functionalized PLGA Microspheres
Ultrasound-Modulated Shape Memory and Payload Release Effects in a Biodegradable Cylindrical Rod Made of Chitosan-Functionalized PLGA Microspheres
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由壳聚糖功能化 PLGA 微球制成的可生物降解圆柱形棒中的超声调制形状记忆和有效负载释放效应
DOI：
10.1021/bm4003464
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发表时间：
2013-06-01
影响因子：
6.2
通讯作者：
Zhang, Yanzhong
中科院分区：
文献类型：
--
作者：
Bao, Min;Zhou, Qihui;Zhang, Yanzhong
具有多种功能的微创植入物和/或支架在临床环境中具有重要意义。本文采用水包油乳液法制备了壳聚糖(CTS)功能化的聚乳酸-乙醇酸共聚(PLGA)微球，其中含有模型负载溶菌酶(LYZ)，然后将复合微球在模具中烧结得到直径为5 mm的圆柱形棒状微球。高强度聚焦超声(HIFU)作为一种独特的技术被用来实现三维结构的形状记忆和有效载荷释放效果。研究发现，在PLGA微球中引入CTS可以使微球的转变温度从45℃调节到50℃，并在一定程度上影响圆柱杆的形状记忆率。形状记忆测试和药物释放实验证明，HIFU可以调节形状恢复过程，并以可切换的方式同步包裹的LyZ在棒内的释放动力学。此外，还可以通过改变声功率和电离时间来控制这两个过程。对超声辐照前后的微球棒进行了力学测试，结果表明其在松质骨范围内具有压缩性能。降解行为的研究表明，CTS的引入也缓解了以PLGA为主的柱状棒的酸性降解特性。因此，利用HIFU，本研究证明了集成在一个基于微球的可生物降解圆柱形结构中的形状恢复和有效载荷释放效果的预期能力。
Minimally invasive implants and/or scaffolds integrated with multiple functionalities are of interest in the clinical settings. In this paper, chitosan (CTS) functionalized poly(lactic-co-glycolic acid) (PLGA) microspheres containing a model payload, lysozyme (Lyz), were prepared by a water-in-oil-in-water emulsion method, from which cylindrical shaped rod (5 mm in diameter) was fabricated by sintering the composite microspheres in a mold. High-intensity focused ultrasound (HIFU) was then employed as a unique technique to enable shape memory and payload release effects of the three-dimensional (3-D) structure. It was found that incorporation of CTS into PLGA microspheres could regulate the transition temperature T-trans of the microsphere from 45 to 50 degrees C and affect shape memory ratio of the fabricated cylindrical rod to some extent. Shape memory test and drug release assay proved that HIFU could modulate the shape recovery process and synchronize the release kinetics of the encapsulated Lyz in the rod in a switchable manner. Moreover, the two processes could be manipulated by varying the acoustic power and insonation duration. Mechanical tests of the microspheres-based rod before and after ultrasound irradiation revealed its compressive properties in the range of trabecular bone. Examination of the degradation behavior indicated that the introduction of CTS into the PLGA microspheres also alleviated acidic degradation characteristic of the PLGA-dominant cylindrical rod. With HIFU, this study thus demonstrated the desired capabilities of shape recovery and payload release effects integrated in one microspheres-based biodegradable cylindrical structure.