固化状态依赖性流变学调控硅弹性体的静电纺丝以用于疏水表面涂层

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中文摘要

背景： 耳蜗植入电极阵列周围的纤维化会增加阻抗并破坏可预测的刺激传播。静电纺丝疏水硅酮涂层是减轻纤维化的一种有前景的策略。然而，硅弹性体的静电纺丝仍然具有挑战性，因为其低玻璃化转变温度会导致沉积纤维在固化完成前塌陷。以往的方法集中于开发原位固化系统，例如加热收集器。尽管已生成纤维状结构，但尚未实现具有互连孔隙的非织造布。方法：开发了一种基于预固化的静电纺丝策略，使得无需聚合物共混物、牺牲性载体聚合物或同轴喷丝头即可制备纯硅弹性体非织造布。将Sylgard 184在丙酮和四氢呋喃中的稀释液在凝胶化前的不同预固化时间进行静电纺丝，并进行流变学表征，以研究固化诱导的流变演变对静电纺丝性的影响。结果：最初，稀释液表现出接近牛顿的流动行为。在失去流动性的不久前，丙酮基体系的最大第一法向应力差增加至3228 Pa，四氢呋喃基体系增加至6722 Pa，同时储能模量增加且剪切变稀行为更明显。这种流变转变与从静电喷雾向静电纺丝的转变相吻合。通过控制固化时间，由Sylgard/四氢呋喃体系成功制备了具有明确纤维几何形状和互连孔隙的非织造结构。通过调整稀释剂和固化时间，实现了21 µm至136 µm的纤维直径。结论：这些发现表明，精确控制固化过程中的流变演变能够制备结构明确的静电纺丝硅弹性体非织造布，为耳蜗植入物上的抗纤维化涂层提供了基础。图解摘要说明了Sylgard 184硅弹性体在40 °C下预固化对其流变性能及后续静电纺丝行为的影响。流变测量，包括剪切粘度和第一法向应力差，与带有加热收集器和红外辅助原位固化的静电纺丝装置示意图一同展示。显微图像比较了预固化180分钟和210分钟后的所得纤维形态。

英文摘要

Fibrosis around cochlear implant electrode arrays increases impedance and disrupts predictable stimulus propagation. Electrospun hydrophobic silicone coatings represent a promising strategy to mitigate fibrosis. However, electrospinning silicone elastomers remains challenging because their low glass transition temperature causes deposited fibers to collapse before curing is complete. Previous approaches have focused on developing in situ curing systems, such as heated collectors. Although fiber-like structures have been generated, nonwovens with interconnected pores have not yet been achieved. A pre-curing-based electrospinning strategy was developed that enables the fabrication of pure silicone elastomer nonwovens without the need for polymer blends, sacrificial carrier polymers, or coaxial spinnerets. Sylgard 184 dilutions in acetone and tetrahydrofuran were electrospun at different pre-curing times prior to gelation and characterized rheologically to investigate the influence of curing-induced rheological evolution on electrospinnability. Initially, the dilutions exhibited near-Newtonian flow behavior. Shortly before loss of flowability, the maximum first normal stress difference increased to 3228 Pa for acetone- and 6722 Pa for tetrahydrofuran-based systems, accompanied by increased storage modulus and more pronounced shear-thinning behavior. This rheological transition coincided with the transition from electrospraying to electrospinning. By controlling the curing time, nonwoven structures with well-defined fiber geometry and interconnected pores were successfully fabricated from Sylgard/tetrahydrofuran systems. Fiber diameters ranging from 21 µm to 136 µm were achieved by adjusting the diluent and curing time. These findings demonstrate that precise control of rheological evolution during curing enables the fabrication of structurally defined electrospun silicone elastomer nonwovens, providing a foundation for anti-fibrotic coatings on cochlear implants. Graphical abstract illustrating the influence of pre-curing Sylgard 184 silicone elastomer at 40 °C on its rheological properties and subsequent electrospinning behavior. Rheological measurements, including shear viscosity and first normal stress difference, are shown alongside a schematic of the electrospinning setup with a heated collector and infrared-assisted in situ curing. Microscopic images compare the resulting fiber morphologies after 180 and 210 minutes of pre-curing.