BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
J Control Release. 2019 Jun 28;304:173-180. doi: 10.1016/j.jconrel.2019.05.017. Epub 2019 May 13.
Spatio-temporally controlled drug release based on conducting polymer films offers a powerful technology to improve the tissue integration for implantable neuroprobes. We here explore the release efficiency of such systems in order to improve the understanding of the release mechanism and allow for optimized implementation of this technology into future drug release applications. By exposing drug loaded PEDOT coatings of different thicknesses to a multitude of release signals, along with optimizing the steps during the polymer synthesis, we could identify a highly reproducible electrostatically controlled drug release next to a slow diffusion driven release component. The release efficiency was moreover observed to be higher for a cyclic voltammetry signal in comparison to release driven by a constant potential. Biphasic current pulses, as used during neural stimulation, did not allow for long enough diffusion times to yield efficient active drug expulsion from the polymer films. A quantitative analysis could confirm an overall linear dependency between drug release and film thickness. The amount of drug released in response to the trigger signals was however not linearly correlated with the amount of charge applied. By combining these findings we could develop a model which accurately describes the drug release mechanism from a PEDOT film. The proposed model thereby points the way for how actively controlled, and diffusion related, release can be tuned for obtaining delivery dynamics tailored to specific applications.
基于导电聚合物薄膜的时空调控药物释放为改善植入式神经探针的组织整合提供了一种强大的技术。我们在这里探索了这种系统的释放效率，以便更好地理解释放机制，并将这项技术优化应用于未来的药物释放应用中。通过将负载药物的 PEDOT 涂层暴露于多种释放信号下，并优化聚合物合成过程中的步骤，我们可以确定一种高度可重复的静电控制药物释放，同时还有缓慢的扩散驱动释放成分。与由恒电位驱动的释放相比，释放效率观察到对循环伏安信号更高。在神经刺激过程中使用的双相电流脉冲由于扩散时间不够长，无法有效地从聚合物薄膜中排出活性药物。定量分析可以证实药物释放与薄膜厚度之间存在总体线性依赖性。然而，响应触发信号释放的药物量与施加的电荷量之间没有线性相关性。通过结合这些发现，我们可以开发一种能够准确描述 PEDOT 薄膜药物释放机制的模型。所提出的模型为如何主动控制和扩散相关的释放提供了方向，以便获得针对特定应用的定制输送动力学。
