Lee Joo-Woon, Serna Francisco, Schmidt Christine E
Biomedical Engineering Department and Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA. jwoonlee@ chungju.ac.kr
Langmuir. 2006 Nov 21;22(24):9816-9. doi: 10.1021/la062129d.
Numerous regenerating tissues respond favorably to electrical stimulation, creating a need for a bioactive conducting platform for tissue engineering applications. The drive for biosensors and electrode coatings further requires control of the surface properties of promising conductive materials such as polypyrrole. Here we present carboxy-endcapped polypyrrole (PPy-alpha-COOH), a unique bioactive conducting polymer with a carboxylic acid layer, composed of a polypyrrole (PPy) surface modified with pyrrole-alpha-carboxylic acid (Py-alpha-COOH). This unique structure is simple to produce, provides a stable bioactive surface via covalent bonds, and preserves bulk properties such as electrical conductivity and mechanical integrity. The chemical structure of this polymer composite was characterized by angle-resolved X-ray photoelectron spectroscopy (XPS), which demonstrated the presence of carboxylic acid functionality on the top surface of conductive PPy. A four-point probe test was used to verify the similar conductivity of PPy-alpha-COOH compared to that of standard PPy. To demonstrate the potential to influence cellular activity, the carboxylic acid monolayer surface was grafted with the cell-adhesive Arg-Gly-Asp (RGD) motif. Human umbilical vein endothelial cells (HUVECs) cultured on RGD-modified PPy-alpha-COOH demonstrated significantly higher adhesion and spreading than on the negative controls PPy-alpha-COOH and unmodified PPy.
许多再生组织对电刺激反应良好，这就需要一个用于组织工程应用的生物活性导电平台。对生物传感器和电极涂层的需求进一步要求控制有前景的导电材料（如聚吡咯）的表面性质。在此，我们展示了羧基封端的聚吡咯（PPy-α-COOH），这是一种独特的具有羧酸层的生物活性导电聚合物，由用吡咯-α-羧酸（Py-α-COOH）修饰的聚吡咯（PPy）表面组成。这种独特的结构易于制备，通过共价键提供稳定的生物活性表面，并保留诸如导电性和机械完整性等本体性质。该聚合物复合材料的化学结构通过角分辨X射线光电子能谱（XPS）进行表征，结果表明导电PPy顶表面存在羧酸官能团。使用四点探针测试来验证PPy-α-COOH与标准PPy相比具有相似的导电性。为了证明其影响细胞活性的潜力，在羧酸单层表面接枝了细胞黏附性的精氨酸-甘氨酸-天冬氨酸（RGD）基序。在RGD修饰的PPy-α-COOH上培养的人脐静脉内皮细胞（HUVECs）显示出比在阴性对照PPy-α-COOH和未修饰的PPy上显著更高的黏附性和铺展性。
