Acta Biomaterialia ( IF 9.4 ) Pub Date : 2020-05-17 , DOI: 10.1016/j.actbio.2020.04.032 Rashed T Rihani 1 , Allison M Stiller 1 , Joshua O Usoro 1 , Jennifer Lawson 1 , Hyun Kim 1 , Bryan J Black 1 , Vindhya Reddy Danda 1 , Jimin Maeng 1 , Victor D Varner 1 , Taylor H Ware 1 , Joseph J Pancrazio 1
|
Intracortical microelectrode arrays (MEAs) are currently limited in their chronic functionality due partially to the foreign body response (FBR) that develops in regions immediately surrounding the implant (typically within 50–100 µm). Mechanically flexible, polymer-based substrates have recently been explored for MEAs as a way of minimizing the FBR caused by the chronic implantation. Nonetheless, the FBR degrades the ability of the device to record neural activity. We are motivated to develop approaches to deploy multiple recording sites away from the initial site of implantation into regions of tissue outside the FBR zone. Liquid Crystal Elastomers (LCEs) are responsive materials capable of programmable and reversible shape change. These hydrophobic materials are also non-cytotoxic and compatible with photolithography. As such, these responsive materials may be well suited to serve as substrates for smart, implantable electronics. This study explores the feasibility of LCE-based deployable intracortical MEAs. LCE intracortical probes are fabricated on a planar substrate and adopt a 3D shape after being released from the substrate. The LCE probes are then fixed in a planar configuration using polyethylene glycol (PEG). The PEG layer dissolves in physiological conditions, allowing the LCE probe to deploy post-implantation. Critically, we show that LCE intracortical probes will deploy within a brain-like agarose tissue phantom. We also show that deployment distance increases with MEA width. A finite element model was then developed to predict the deformed shape of the deployed probe when embedded in an elastic medium. Finally, LCE-based deployable intracortical MEAs were capable of maintaining electrochemical stability, recording extracellular signals from cortical neurons in vivo, and deploying recording sites greater than 100 µm from the insertion site in vivo. Taken together, these results suggest the feasibility of using LCEs to develop deployable intracortical MEAs.
Statement of Significance
Deployable MEAs are a recently developed class of neural interfaces that aim to shift the recording sites away from the region of insertion to minimize the negative effects of FBR on the recording performance of MEAs. In this study, we explore LCEs as a potential substrate for deployable MEAs. The novelty of this study lies in the systematic and programmable deployment offered by LCE-based intracortical MEAs. These results illustrate the feasibility and potential application of LCEs as a substrate for deployable intracortical MEAs.
中文翻译：
可展开的，基于液晶弹性体的皮质内探针。
皮质内微电极阵列（MEAs）的长期功能性目前受到限制，部分原因是异物反应（FBR）在植入物周围的区域（通常在50至100 µm之内）产生。最近，人们已开发出机械柔性的，基于聚合物的基材用于MEA，以最大程度地减少由长期植入引起的FBR。但是，FBR会降低设备记录神经活动的能力。我们有动力开发出将多个记录位点从植入的初始位点部署到FBR区域以外的组织区域的方法。液晶弹性体（LCE）是具有响应能力的材料，能够进行可编程和可逆的形状更改。这些疏水材料也是无细胞毒性的，并且与光刻兼容。因此，这些响应性材料可能非常适合用作智能，可植入电子设备的基材。这项研究探讨了基于LCE的可部署皮质内MEA的可行性。LCE皮质内探针在平面基板上制造，并在从基板释放后采用3D形状。然后使用聚乙二醇（PEG）将LCE探针固定在平面配置中。PEG层在生理条件下溶解，从而使LCE探针可以在植入后展开。至关重要的是，我们显示LCE皮质内探针将部署在大脑样琼脂糖组织模型中。我们还表明，部署距离随着MEA宽度的增加而增加。然后开发了一个有限元模型，以预测当嵌入弹性介质中时展开的探头的变形形状。最后，在体内，并从体内插入位置出发部署大于100μm的记录部位。两者合计，这些结果表明使用LCE来开发可部署的皮质内MEA的可行性。
重要声明
可部署的MEA是最近开发的一类神经接口，旨在使记录部位远离插入区域，以最大程度地减小FBR对MEA的记录性能的负面影响。在这项研究中，我们探索了LCE作为可部署MEA的潜在基质。这项研究的新颖之处在于基于LCE的皮质内MEA提供的系统性和可编程部署。这些结果说明了LCE作为可部署皮质内MEA的底物的可行性和潜在应用。
京公网安备 11010802027423号