Interest in stimuli-responsive materials has increased rapidly, leading to a multitude of innovative applications in biomedical design. This study seeks to induce controlled shape memory effects through induction heating of magnetic polymer nanocomposites while retaining thermal consistency within attached hydrogel composites for various biomedical applications. Three commonly used polymer matrices were embedded with varying concentrations of magnetite nanoparticles to determine minimum and maximum loading effects on induction heating response and optimal shape memory effects. Thermal and morphological characterizations were performed to determine transition temperatures, followed by induction heating tests by way of an induction coil at different magnetic field strengths to determine heating rates, activation times and activation rates of shape memory effects for each polymer nanocomposite composition. Simultaneously, mechanically tunable sodium alginate and cellulose nanocrystal hydrogel composites were fabricated and characterized to determine hydrational, mechanical and thermal buffering properties. Induction heating tests revealed that all substrates exhibited a heating response; however, shape memory effects were observed only in poly(vinyl acetate) and Nylon 11. Moreover, all hydrogels displayed promising thermal dissipation, <1°C per 20 s of heating, preventing any potential thermal shock to biological components. These unique properties will allow for successful employment of these multi-composite scaffolds in a multitude of biological applications.

中文翻译：

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通过感应加热控制磁性聚合物纳米复合材料的形状记忆效应

对刺激响应材料的兴趣迅速增加，导致了生物医学设计中的众多创新应用。本研究旨在通过对磁性聚合物纳米复合材料进行感应加热来诱导受控的形状记忆效应，同时在各种生物医学应用中保持附着的水凝胶复合材料内的热一致性。三种常用的聚合物基质嵌入了不同浓度的磁铁矿纳米粒子，以确定对感应加热响应和最佳形状记忆效应的最小和最大负载影响。进行热和形态表征以确定转变温度，然后通过感应线圈在不同磁场强度下进行感应加热测试，以确定加热速率，每种聚合物纳米复合材料组合物的形状记忆效应的活化时间和活化率。同时，制造并表征了机械可调的海藻酸钠和纤维素纳米晶水凝胶复合材料，以确定水合、机械和热缓冲性能。感应加热测试显示所有基板都表现出加热响应；然而，仅在聚醋酸乙烯酯和尼龙 11 中观察到形状记忆效应。此外，所有水凝胶都显示出良好的散热性，每 20 秒加热 <1°C，防止对生物成分的任何潜在热冲击。这些独特的特性将允许在众多生物应用中成功使用这些多复合支架。机械可调的海藻酸钠和纤维素纳米晶水凝胶复合材料被制造和表征以确定水合、机械和热缓冲性能。感应加热测试显示所有基板都表现出加热响应；然而，仅在聚醋酸乙烯酯和尼龙 11 中观察到形状记忆效应。此外，所有水凝胶都显示出良好的散热性，每 20 秒加热 <1°C，防止对生物成分的任何潜在热冲击。这些独特的特性将允许在众多生物应用中成功使用这些多复合支架。机械可调的海藻酸钠和纤维素纳米晶水凝胶复合材料被制造和表征以确定水合、机械和热缓冲性能。感应加热测试显示所有基板都表现出加热响应；然而，仅在聚醋酸乙烯酯和尼龙 11 中观察到形状记忆效应。此外，所有水凝胶都显示出良好的散热性，每 20 秒加热 <1°C，防止对生物成分的任何潜在热冲击。这些独特的特性将允许在众多生物应用中成功使用这些多复合支架。感应加热测试显示所有基板都表现出加热响应；然而，仅在聚醋酸乙烯酯和尼龙 11 中观察到形状记忆效应。此外，所有水凝胶都显示出良好的散热性，每 20 秒加热 <1°C，防止对生物成分的任何潜在热冲击。这些独特的特性将允许在众多生物应用中成功使用这些多复合支架。感应加热测试显示所有基板都表现出加热响应；然而，仅在聚醋酸乙烯酯和尼龙 11 中观察到形状记忆效应。此外，所有水凝胶都显示出良好的散热性，每 20 秒加热 <1°C，防止对生物成分的任何潜在热冲击。这些独特的特性将允许在众多生物应用中成功使用这些多复合支架。