Smooth and nano-rough flat gold electrodes were manufactured with controlled Ra of 0.8 and 4.5 nm, respectively. Further nano-rough surfaces (Ra 4.5 nm) were patterned with arrays of micro-pillars 500 μm high. All these electrodes were implemented in pure cultures of Geobacter sulfurreducens, under a constant potential of 0.1 V/SCE and with a single addition of acetate 10 mM to check the early formation of microbial anodes. The flat smooth electrodes produced an average current density of 0.9 A·m⁻². The flat nano-rough electrodes reached 2.5 A·m⁻² on average, but with a large experimental deviation of ±2.0 A·m⁻². This large deviation was due to the erratic colonization of the surface but, when settled on the surface, the cells displayed current density that was directly correlated to the biofilm coverage ratio.

The micro-pillars considerably improved the experimental reproducibility by offering the cells a quieter environment, facilitating biofilm development. Current densities of up to 8.5 A·m⁻² (per projected surface area) were thus reached, in spite of rate limitation due to the mass transport of the buffering species, as demonstrated by numerical modelling. Nano-roughness combined with micro-structuring increased current density by a factor close to 10 with respect to the smooth flat surface.

光滑和纳米粗糙的扁平金电极的控制Ra分别为0.8和4.5 nm。进一步用500μm高的微柱阵列对纳米粗糙表面（Ra 4.5 nm）进行构图。所有这些电极均在纯净的Geobacter sulphreducens培养物中实现，在0.1 V / SCE的恒定电势下，仅添加10 mM乙酸盐即可检查微生物阳极的早期形成。平坦的光滑电极产生0.9 A·m ^-2的平均电流密度。平坦的纳米粗糙电极平均达到2.5 A·m ^-2，但实验偏差为±2.0 A·m ^-2。。这种大的偏差是由于表面的定植不稳定，但是当沉积在表面上时，细胞显示出的电流密度与生物膜的覆盖率直接相关。

微柱通过为细胞提供更安静的环境，促进了生物膜的发育，大大提高了实验的可重复性。尽管通过数值模拟证明了由于缓冲物质的质量传递而造成的速率限制，但仍达到了高达8.5 A·m ^-2（每个投影表面积）的电流密度。纳米粗糙度与微结构相结合，相对于光滑的平坦表面，电流密度增加了近10倍。