Microscopic interactions between electrochemical sensors and biomolecules critically influence the sensitivity. Here, we report an unexpected dependence of the sensitivity on the upper potential limit (UPL) in voltammetry experiments. In particular, we find that the sensitivity of substrate-supported nano-graphitic micro-sensors in response to dopamine increases almost linearly with the inverse of UPL in voltammetry experiments with rapid potential sweeps. Our experiments and multi-physics simulations reveal that the main cause behind this phenomenon is the UPL-induced electrostatic force that influences the steady-state number of dopamine molecules on the sensor surface. Our findings illustrate a new strategy for enhancing the performance of planar electrochemical micro-sensors.

电化学传感器与生物分子之间的微观相互作用会严重影响灵敏度。在这里，我们报告了伏安法实验中灵敏度对电位上限（UPL）的意外依赖。特别是，我们发现，在具有快速电势扫描的伏安实验中，基质支持的纳米石墨微传感器对多巴胺的响应灵敏度几乎与UPL的变化呈线性关系。我们的实验和多物理场仿真表明，此现象背后的主要原因是UPL感应的静电力影响了传感器表面多巴胺分子的稳态数量。我们的发现说明了一种提高平面电化学微型传感器性能的新策略。