Bio-inspired hybrid microelectrodes: a hybrid solution to improve long-term performance of chronic intracortical implants.
Bio-inspired hybrid microelectrodes: a hybrid solution to improve long-term performance of chronic intracortical implants.
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DOI：
10.3389/fneng.2014.00007
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发表时间：
2014-01-01
期刊：
影响因子：
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通讯作者：
Fadiga, Luciano
中科院分区：
文献类型：
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作者：
De Faveri, Sara;Maggiolini, Emma;Fadiga, Luciano
目前，允许在人类患者的大脑中进行慢性电刺激和记录的植入物的使用受到一系列事件的限制，这些事件会导致电极表面和周围组织随着时间的推移而恶化。失败的主要原因是组织炎症反应，最终导致神经元丢失和胶质包封，导致电极-电解质阻抗进行性增加。在这里，我们描述了一种创造仿生电极的新方法，以模仿宿主组织的机械特性和生物组成。通过减少组织反应和改善电耦合，这种组合有很大的潜力来增加植入物的使用寿命。我们的方法是在电极上包裹一层水凝胶层内的重编程神经细胞或胶质细胞。我们选择纤维蛋白作为水凝胶，以大鼠脑原代海马神经元或星形胶质细胞作为细胞层。我们证明纤维蛋白涂层具有高度的生物相容性，形成厚度可控的均匀涂层，不改变微电极的电化学特性，并允许高质量的记录。此外，与裸丝相比，随着时间的推移，它减少了宿主反应性星形胶质细胞的数量，并且在植入后7天内被周围组织完全重新吸收，避免了水凝胶肿胀的常见问题。星形胶质细胞和神经元都可以在纤维蛋白水凝胶内成功生长在电极表面，而不会改变微电极的电化学性质。因此，这种生物混合装置在改善神经元-电极界面的电集成和支持神经假体的长期成功方面具有良好的潜力。
The use of implants that allow chronic electrical stimulation and recording in the brain of human patients is currently limited by a series of events that cause the deterioration over time of both the electrode surface and the surrounding tissue. The main reason of failure is the tissue inflammatory reaction that eventually causes neuronal loss and glial encapsulation, resulting in a progressive increase of the electrode-electrolyte impedance. Here, we describe a new method to create bio-inspired electrodes to mimic the mechanical properties and biological composition of the host tissue. This combination has a great potential to increase the implant lifetime by reducing tissue reaction and improving electrical coupling. Our method implies coating the electrode with reprogrammed neural or glial cells encapsulated within a hydrogel layer. We chose fibrin as a hydrogel and primary hippocampal neurons or astrocytes from rat brain as cellular layer. We demonstrate that fibrin coating is highly biocompatible, forms uniform coatings of controllable thickness, does not alter the electrochemical properties of the microelectrode and allows good quality recordings. Moreover, it reduces the amount of host reactive astrocytes - over time - compared to a bare wire and is fully reabsorbed by the surrounding tissue within 7 days after implantation, avoiding the common problem of hydrogels swelling. Both astrocytes and neurons could be successfully grown onto the electrode surface within the fibrin hydrogel without altering the electrochemical properties of the microelectrode. This bio-hybrid device has therefore a good potential to improve the electrical integration at the neuron-electrode interface and support the long-term success of neural prostheses.