Department of Chemical and Biomolecular Engineering, University of Akron, Akron, OH 44325, USA.
Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
Acta Biomater. 2018 Jul 15;75:161-170. doi: 10.1016/j.actbio.2018.06.002. Epub 2018 Jun 4.
Poly(3,4-ethylenedioxythiophene) (PEDOT) has been widely studied in recent decades due to its high stability, biocompatibility, low redox potential, moderate band gap, and optical transparency in its conducting state. However, for its long-term in vivo applications, the biocompatibility of PEDOT still needs to be improved. To address this challenge, zwitterionic poly(sulfobetaine 3,4-ethylenedioxythiophene) (PSBEDOT) that contains EDOT backbone with sulfobetaine functional side chains was developed in our previous study. Although PSBEDOT showed great resistance to proteins, cells, and bacteria, it is still not clear how the zwitterionic sulfobetaine side chain affects the electrochemical properties of the polymer and reactivity of the monomer. To achieve better understanding of the structure-function relationships of zwitterionic conducting polymers, we synthesized two derivatives of PSBEDOT, PSBEDOT-4 and PSBEDOT-5, by introducing the alkoxyl spacer between PEDOT backbone and sulfobetaine side chain. The interfacial impedance of PSBEDOT-4 and PSBEDOT-5 was examined by electrochemical impedance spectroscopy and showed significant improvement which is about 20 times lower than PSBEDOT on both gold and indium tin oxide substrates at 1 Hz. In the protein adsorption study, PSBEDOT, PSBEDOT-4 and PSBEDOT-5 exhibited comparable resistance to the fibrinogen solution. All three polymers had low protein adsorption around 3-5% comparing to PEDOT. Additionally, the morphology of PSBEDOT, PSBEDOT-4 and PSBEDOT-5 have been investigated by scanning electron microscopy. We believe that these stable and biocompatible materials can be excellent candidates for developing long-term bioelectronic devices.
To address the challenges associated with existing conducting polymers for bioelectronics, we developed a versatile and high performance zwitterionic conducting material platform with excellent stability, electrochemical, antifouling and controllable antimicrobial/antifouling properties. In this work, we developed two high-performance conducting polymers and systematically investigated how the structure affects their properties. Our study shows we can accurately tune the molecular structure of the monomer to improve the performance of zwitterionic conducting polymer. This zwitterionic conducting polymer platform may dramatically increase the performance and service life of bio-electrochemical devices for many long-term applications, such as implantable biosensing, tissue engineering, wound healing, robotic prostheses, biofuel cell etc., which all require high performance conducting materials with excellent antifouling property/biocompatibility at complex biointerfaces.
聚（3,4-亚乙基二氧噻吩）（PEDOT）由于其高稳定性、生物相容性、低氧化还原电位、适度的能带隙和在其导带状态下的光学透明度，在过去几十年中得到了广泛的研究。然而，为了其在体内的长期应用，PEDOT 的生物相容性仍需要提高。为了解决这一挑战，我们在之前的研究中开发了含有 EDOT 主链和磺酸甜菜碱官能侧链的两性离子聚（磺酸甜菜碱 3,4-亚乙基二氧噻吩）（PSBEDOT）。尽管 PSBEDOT 显示出对蛋白质、细胞和细菌的高抵抗力，但仍不清楚两性离子磺酸甜菜碱侧链如何影响聚合物的电化学性质和单体的反应性。为了更好地理解两性离子导电聚合物的结构-功能关系，我们通过在 PEDOT 主链和磺酸甜菜碱侧链之间引入烷氧基间隔基，合成了 PSBEDOT 的两种衍生物 PSBEDOT-4 和 PSBEDOT-5。通过电化学阻抗谱研究了 PSBEDOT-4 和 PSBEDOT-5 的界面阻抗，结果表明，在 1 Hz 时，它们在金和铟锡氧化物衬底上的阻抗分别比 PSBEDOT 低约 20 倍。在蛋白质吸附研究中，PSBEDOT、PSBEDOT-4 和 PSBEDOT-5 对纤维蛋白溶液表现出相当的抵抗力。与 PEDOT 相比，这三种聚合物的蛋白质吸附率均在 3-5%左右。此外，还通过扫描电子显微镜研究了 PSBEDOT、PSBEDOT-4 和 PSBEDOT-5 的形态。我们相信，这些稳定且具有生物相容性的材料可以成为开发长期生物电子设备的优秀候选材料。
为了解决生物电子学中现有导电聚合物所面临的挑战，我们开发了一种多功能、高性能的两性离子导电材料平台，具有优异的稳定性、电化学、抗污和可控的抗菌/抗污性能。在这项工作中，我们开发了两种高性能导电聚合物，并系统地研究了结构如何影响它们的性能。我们的研究表明，我们可以精确地调整单体的分子结构来提高两性离子导电聚合物的性能。这种两性离子导电聚合物平台可能会极大地提高生物电化学器件的性能和使用寿命，用于许多长期应用，如可植入生物传感、组织工程、伤口愈合、机器人假肢、生物燃料电池等，这些应用都需要在复杂的生物界面上具有优异的抗污性/生物相容性的高性能导电材料。
