Stimuli-responsive materials that exhibit a mechanical response to specific biological conditions are of considerable interest for responsive, implantable medical devices. Herein, we report the synthesis, processing and characterization of oxidation-responsive liquid crystal elastomers that demonstrate programmable shape changes in response to reactive oxygen species. Direct ink writing (DIW) is used to fabricate Liquid Crystal Elastomers (LCEs) with programmed molecular orientation and anisotropic mechanical properties. LCE structures were immersed in different media (oxidative, basic and saline) at body temperature to measure in vitro degradation. Oxidation-sensitive hydrophobic thioether linkages transition to hydrophilic sulfoxide and sulfone groups. The introduction of these polar moieties brings about anisotropic swelling of the polymer network in an aqueous environment, inducing complex shape changes. 3D-printed uniaxial strips exhibit 8% contraction along the nematic director and 16% orthogonal expansion in oxidative media, while printed LCEs azimuthally deform into cones 19 times their original thickness. Ultimately, these LCEs degrade completely. In contrast, LCEs subjected to basic and saline solutions showed no apparent response. These oxidation-responsive LCEs with programmable shape changes may enable a wide range of applications in target specific drug delivery systems and other diagnostic and therapeutic tools.

中文翻译：

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氧化敏感型液晶弹性体中的降解诱导驱动

对于响应性的，可植入的医疗装置，表现出对特定生物学条件的机械响应的刺激响应性材料引起了极大的兴趣。在这里，我们报告了氧化反应性液晶弹性体的合成，加工和表征，这些反应弹性体显示了响应活性氧物种的可编程形状变化。直接墨水书写（DIW）用于制造具有可编程分子取向和各向异性机械性能的液晶弹性体（LCE）。将LCE结构在人体温度下浸入不同的介质（氧化性，碱性和盐水）中以测量体外降解。氧化敏感的疏水硫醚键过渡为亲水亚砜和砜基团。这些极性部分的引入在水性环境中引起聚合物网络的各向异性溶胀，引起复杂的形状变化。3D打印的单轴带沿向列导向器显示8％的收缩率，在氧化介质中显示16％的正交膨胀率，而打印的LCE沿方位角变形为原始厚度的19倍的圆锥体。最终，这些LCE会完全降解。相反，经受碱性和盐溶液的LCE没有显示出明显的反应。这些具有可编程形状变化的氧化反应性LCE可以在目标特定的药物输送系统以及其他诊断和治疗工具中广泛应用。3D打印的单轴条沿向列导向器显示8％的收缩率，在氧化介质中显示16％的正交膨胀率，而打印的LCE沿方位角变形为原始厚度的19倍的圆锥体。最终，这些LCE会完全降解。相反，经受碱性和盐溶液的LCE没有显示出明显的反应。这些具有可编程形状变化的氧化反应性LCE可以在目标特定的药物输送系统以及其他诊断和治疗工具中广泛应用。3D打印的单轴条沿向列导向器显示8％的收缩率，在氧化介质中显示16％的正交膨胀率，而打印的LCE沿方位角变形为原始厚度的19倍的圆锥体。最终，这些LCE会完全降解。相反，经受碱性和盐溶液的LCE没有显示出明显的反应。这些具有可编程形状变化的氧化反应性LCE可以在目标特定的药物输送系统以及其他诊断和治疗工具中广泛应用。