Shape memory polymer (SMP) microspheres possess controllable physicochemical properties, internal cavities capable of loading drugs or nanoparticles, and inherent intelligence, making them suitable for various biomedical applications. In this research, we utilized tri-n-butyl citrate (TBC) to lower the glass transition temperature of shape memory polylactic acid (PLA) to approximate oral temperature. Following this, we introduced oleic acid-modified FeO nanoparticles to confer magnetism to the material. Subsequently, SMP microspheres with a core-shell structure encapsulating FeO particles were prepared using the emulsion-solvent evaporation method, and we carefully controlled their particle size and morphology to match the diameter of dentinal tubules. Our investigation focused on applying these magnetically guided microspheres, which exhibited excellent shape memory performance, for sealing dentinal tubules. These microspheres displayed the ability to move directionally under the influence of a magnetic field. As a result, they could be attracted into the interior of dentinal tubules in their temporary shape and then revert to their initial shape upon heating at 40 °C, thereby achieving the closure of dentinal tubules effectively. The microsphere entry rate during the tubule closure process was found to be 93.33 ±2.82%, with a corresponding sealing rate of 85.41 ±7.11%. The successful demonstration of magnetic-guided movement and the utilization of the shape memory function for dentinal tubule sealing significantly expand the potential applications of SMP microspheres in the field of biomedical science.

中文翻译：

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用于牙本质小管封闭的磁引导形状记忆PLA/TBC/Fe3O4微球

形状记忆聚合物（SMP）微球具有可控的理化性质、能够装载药物或纳米颗粒的内腔以及固有的智能，使其适用于各种生物医学应用。在这项研究中，我们利用柠檬酸三正丁酯（TBC）来降低形状记忆聚乳酸（PLA）的玻璃化转变温度以接近口腔温度。随后，我们引入了油酸改性的 Fe3O 纳米颗粒来赋予材料磁性。随后，采用乳液-溶剂蒸发法制备了具有核壳结构的封装Fe3O颗粒的SMP微球，并仔细控制其粒径和形貌以匹配牙本质小管的直径。我们的研究重点是应用这些具有优异形状记忆性能的磁引导微球来密封牙本质小管。这些微球表现出在磁场影响下定向移动的能力。结果，它们可以以临时形状被吸引到牙本质小管内部，然后在40℃加热时恢复到初始形状，从而有效地实现牙本质小管的闭合。肾小管封闭过程中微球的进入率为93.33±2.82%，相应的封闭率为85.41±7.11%。磁引导运动的成功演示以及利用形状记忆功能进行牙本质小管密封，显着扩展了SMP微球在生物医学领域的潜在应用。