Department of Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109, USA.
Small. 2010 Feb 5;6(3):421-9. doi: 10.1002/smll.200901868.
An in vitro comparison of conducting-polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same deposition charge density, PPy films and nanotubes grow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44 C cm(-2)), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 +/- 2.1 kOmega for PPy nanotubes and 2.5 +/- 1.4 kOmega for PEDOT nanotubes at 1 kHz) and higher CCD (184 +/- 5.3 mC cm(-2) for PPy nanotubes and 392 +/- 6.2 mC cm(-2) for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 +/- 13.3 kOmega at 1 kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 +/- 0.5 mC cm(-2)). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxide while PPy and PEDOT films delaminate. In experiments of primary neurons with conducting-polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 +/- 95 microm for PPy nanotubes and 2100 +/- 150 microm for PEDOT nanotubes) than their film counterparts. These findings suggest that conducting-polymer nanotubes may improve the long-term function of neural microelectrodes.
本文报告了聚(3,4-亚乙基二氧噻吩)(PEDOT)和聚吡咯(PPy)导电聚合物纳米管与其薄膜对应物的体外比较。比较了阻抗、电荷容量密度(CCD)、分层倾向和神经突生长。对于相同的沉积电荷量，PPy 薄膜和纳米管相对较快地垂直生长，而 PEDOT 薄膜和纳米管则更多地侧向生长。对于相同的沉积电荷量(1.44 C cm(-2))，PPy 纳米管和 PEDOT 纳米管的阻抗较低(PPy 纳米管为 19.5 +/- 2.1 kOmega，1 kHz；PEDOT 纳米管为 2.5 +/- 1.4 kOmega，1 kHz)，电荷容量密度较高(PPy 纳米管为 184 +/- 5.3 mC cm(-2)，PEDOT 纳米管为 392 +/- 6.2 mC cm(-2))。然而，与薄膜对应物相比，PEDOT 纳米管将神经电极部位的阻抗降低了约两个数量级(裸 Ir 为 468.8 +/- 13.3 kOmega，1 kHz)，并将电荷密度的容量提高了约三个数量级(裸 Ir 为 0.1 +/- 0.5 mC cm(-2))。在循环伏安测量期间，PPy 和 PEDOT 纳米管都在二氧化硅表面保持附着，而 PPy 和 PEDOT 薄膜则分层。在含有导电聚合物纳米管的原代神经元实验中，培养的背根神经节外植体保持更完整，并表现出更长的神经突(PPy 纳米管为 1400 +/- 95 微米，PEDOT 纳米管为 2100 +/- 150 微米)。这些发现表明，导电聚合物纳米管可能改善神经微电极的长期功能。
