Department of Chemistry, Materials, and Chemical Engineering G. Natta, Politecnico di Milano, Milano, Italy.
J Appl Biomater Funct Mater. 2012 Sep 27;10(2):119-26. doi: 10.5301/JABFM.2012.9706.
Porous Shape Memory Polymers (SMPs) are ideal candidates for the fabrication of defect fillers, able to support tissue regeneration via minimally invasive approaches. In this regard, control of pore size, shape and interconnection is required to achieve adequate nutrient transport and cell ingrowth. Here, we assessed the feasibility of the preparation of SMP porous structures and characterized their chemico-physical properties and in vitro cell response.
SMP scaffolds were obtained via solvent casting/particulate leaching of gelatin microspheres, prepared via oil/water emulsion. A solution of commercial polyether-urethane (MM-4520, Mitsubishi Heavy Industries) was cast on compacted microspheres and leached-off after polymer solvent evaporation. The obtained structures were characterized in terms of morphology (SEM and micro-CT), thermo-mechanical properties (DMTA), shape recovery behavior in compression mode, and in vitro cytocompatibility (MG63 Osteoblast-like cell line).
The fabrication process enabled easy control of scaffold morphology, pore size, and pore shape by varying the gelatin microsphere morphology. Homogeneous spherical and interconnected pores have been achieved together with the preservation of shape memory ability, with recovery rate up to 90%. Regardless of pore dimensions, MG63 cells were observed adhering and spreading onto the inner surface of the scaffolds obtained for up to seven days of static in vitro tests.
A new class of SMP porous structures has been obtained and tested in vitro: according to these preliminary results reported, SMP scaffolds can be further exploited in the design of a new class of implantable devices.
多孔形状记忆聚合物（SMP）是制造缺陷填充剂的理想候选材料，能够通过微创方法支持组织再生。在这方面，需要控制孔径、形状和连通性，以实现足够的营养物质运输和细胞内生长。在这里，我们评估了制备 SMP 多孔结构的可行性，并对其化学物理性质和体外细胞反应进行了表征。
通过溶剂浇铸/颗粒浸出明胶微球制备 SMP 支架，明胶微球通过油/水乳液制备。将商业聚醚-聚氨酯（MM-4520，三菱重工业）溶液浇铸在压实的微球上，并在聚合物溶剂蒸发后浸出。从形态学（SEM 和 micro-CT）、热机械性能（DMTA）、压缩模式下的形状恢复行为以及体外细胞相容性（MG63 成骨样细胞系）等方面对获得的结构进行了表征。
通过改变明胶微球的形态，可以轻松控制支架的形态、孔径和孔形状。已经实现了均匀的球形和互连的孔，同时保持了形状记忆能力，恢复率高达 90%。无论孔径如何，MG63 细胞在静态体外测试长达七天的时间内都被观察到附着并在获得的支架内表面上展开。
已经获得了一类新的 SMP 多孔结构并进行了体外测试：根据这些初步结果，SMP 支架可以进一步用于设计新型植入式装置。
