In Situ Porous Structures: A Unique Polymer Erosion Mechanism in Biodegradable Dipeptide-based Polyphosphazene and Polyester Blends Producing Matrices for Regenerative Engineering.
In Situ Porous Structures: A Unique Polymer Erosion Mechanism in Biodegradable Dipeptide-based Polyphosphazene and Polyester Blends Producing Matrices for Regenerative Engineering.
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原位多孔结构：可生物降解的二肽基聚磷腈和聚酯共混物中独特的聚合物侵蚀机制，用于生产再生工程基质。
DOI：
10.1002/adfm.201090073
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发表时间：
2010
影响因子：
19
通讯作者：
Laurencin,CatoT
中科院分区：
文献类型：
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作者：
Deng,Meng;Nair,LakshmiS;Nukavarapu,SyamP;Kumbar,SangameshG;Jiang,Tao;Weikel,ArlinL;Krogman,NicholasR;Allcock,HarryR;Laurencin,CatoT
合成的生物可降解聚合物可作为临时基质，在再生医学中适应细胞浸润和组织生长。为了允许组织向内生长和营养输送，传统的三维（3D）支架必须预制有互连的多孔结构。在这里，一个独特的聚合物侵蚀过程，通过该过程，聚合物基体从一个固体连贯的薄膜发展到一个组装的微球与互连的3D多孔结构是第一次证明。该聚合物体系是在聚磷腈-聚酯共混物的高度通用平台上开发的。用亲水性甘氨酰甘氨酸二肽和疏水性4-苯基苯氧基基团共取代聚磷腈主链产生具有强氢键结合能力的聚合物。聚酯组分的快速水解允许形成填充有自组装聚磷腈球的3D空隙空间。这种自组装多孔结构的表征揭示了球体之间的大孔（10-100 μm）以及球体表面上的微米和纳米孔。使用大鼠皮下植入模型在体内证实了类似的降解模式。12周的植入导致具有82-87%孔隙率的互连多孔结构。通过组织学观察到的微球之间的细胞浸润和胶原组织向内生长证实了原位3D互连多孔结构的形成。经确定，原位多孔结构是由共混物中独特的氢键作用导致的，促进了三阶段降解机制。该动态成孔支架的稳健组织向内生长证明了该系统作为再生医学中用于开发平衡降解与组织形成的固体基质的新策略的实用性。
Synthetic biodegradable polymers serve as temporary substrates that accommodate cell infiltration and tissue in‐growth in regenerative medicine. To allow tissue in‐growth and nutrient transport, traditional three‐dimensional (3D) scaffolds must be prefabricated with an interconnected porous structure. Here a unique polymer erosion process through which polymer matrices evolve from a solid coherent film to an assemblage of microspheres with an interconnected 3D porous structure is demonstrated for the first time. This polymer system is developed on the highly versatile platform of polyphosphazene‐polyester blends. Co‐substituting a polyphosphazene backbone with both hydrophilic glycylglycine dipeptide and hydrophobic 4‐phenylphenoxy group generates a polymer with strong hydrogen bonding capacity. Rapid hydrolysis of the polyester component permits the formation of 3D void space filled with self‐assembled polyphosphazene spheres. Characterization of such self‐assembled porous structures reveals macropores (10–100 μm) between spheres as well as micro‐ and nanopores on the sphere surface. A similar degradation pattern is confirmed In vivo using a rat subcutaneous implantation model. 12 weeks of implantation results in an interconnected porous structure with 82–87% porosity. Cell infiltration and collagen tissue in‐growth between microspheres observed by histology confirms the formation of an in situ 3D interconnected porous structure. It is determined that the in situ porous structure results from unique hydrogen bonding in the blend promoting a three‐stage degradation mechanism. The robust tissue in‐growth of this dynamic pore forming scaffold attests to the utility of this system as a new strategy in regenerative medicine for developing solid matrices that balance degradation with tissue formation.