Annu Int Conf IEEE Eng Med Biol Soc. 2023 Jul;2023:1-6. doi: 10.1109/EMBC40787.2023.10341162.
Flexible electrodes are becoming a topic of interest for a range of applications including implantation. They can be used for neural signal recording and for electrical stimulation of atrophying muscles. Unlike the traditionally used metal electrodes that are harsh to the body's tissues, flexible electrodes conduct electricity while preserving the delicate tissues. Polydimethylsiloxane (PDMS), a non-conductive synthetic polymer characterized by its flexibility, low cost, biocompatibility, and durability during implantation, has been explored as a matrix for flexible electrodes. This study reports the synthesis of composite boronic acid-modified carbon dots (BA-CDs)/PDMS electrode materials. The performance of the composite electrode is evaluated electrochemically (for its conductivity and charge storage capacity) and mechanically (Young's modulus). Furthermore, the effect of increasing the PDMS crosslinking density on the electrode's performance is studied based on the hypothesis that a higher crosslinking will bring the BA-CDs closer together, thereby facilitating the movement of electrons. Results of this study showed that incorporating 10% BA-CDs dispersed with 16% glycerol in 74% PDMS with a higher crosslinking density resulted in a bulk impedance of 47.7 Ω and a conductivity of 2.68×10 S/cm, both of which surpassed that of the same composition with lower crosslinking. The synthesized flexible electrode material was capable of charge storage although the charge storage capacity (0.00365 mC/cm) was lower than the safe limit for some tissue activation. Furthermore, the electrode maintained a modulus of elasticity (0.2322 MPa) that is compatible with biological soft tissues.Clinical Relevance- This study reports a conductive electrode that has a flexibility compatible with that of biological tissues for future purposes such as neural signal recording and tissue electrical stimulation (e.g. atrophying muscles). The reported BA-CD/PDMS electrode overcomes the limitations of the harsh metals previously used as implantable electrodes that harm the biological tissues due to their high rigidity.
柔性电极在包括植入物在内的各种应用中成为研究热点。它们可用于神经信号记录和萎缩肌肉的电刺激。与传统使用的对身体组织有刺激性的金属电极不同，柔性电极在导电的同时还能保护脆弱的组织。聚二甲基硅氧烷（PDMS）是一种非导电的合成聚合物，具有柔韧性、低成本、生物相容性和在植入过程中的耐用性，已被探索作为柔性电极的基质。本研究报告了复合硼酸修饰碳点（BA-CDs）/PDMS 电极材料的合成。通过电化学（导电性和电荷存储能力）和机械（杨氏模量）评估复合电极的性能。此外，基于增加 PDMS 交联密度会使 BA-CDs 更接近的假设，研究了增加电极性能的交联密度对电极性能的影响。研究结果表明，在 PDMS 交联密度较高的情况下，将 10%BA-CDs 分散在 16%甘油中的 74%PDMS 中，得到的复合电极的体阻抗为 47.7 Ω，电导率为 2.68×10 S/cm，均高于交联密度较低的相同组成的电极。所合成的柔性电极材料虽然电荷存储容量（0.00365 mC/cm）低于某些组织激活的安全限值，但仍具有电荷存储能力。此外，该电极保持了与生物软组织相容的弹性模量（0.2322 MPa）。临床意义-本研究报告了一种具有与生物组织相适应的柔韧性的导电电极，可用于未来的神经信号记录和组织电刺激等用途（例如萎缩肌肉）。与之前用作植入式电极的硬性金属相比，所报道的 BA-CD/PDMS 电极克服了对生物组织有刺激性的限制。
