Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634, USA.
Nanotechnology. 2013 Sep 6;24(35):355702. doi: 10.1088/0957-4484/24/35/355702. Epub 2013 Aug 8.
We show that electrochemical formation of long probes with nanosharp tips can be controlled by choosing an appropriate thermodynamic pathway of metal to metal oxide and hydroxide transformation. Currently, convection-limited electropolishing (CLE) is extensively used. Nanosharp probes are produced by electrochemically etching a wire until it breaks into two pieces. This process is difficult to control because of the complexity of the associated hydrodynamic flows. We introduce transport-limited electropolishing (TLE), where the electrochemical reaction results in the formation of metal oxides and hydroxides which form a porous surface layer hindering the flow of electrolyte. The developed TLE method enables one to make long tapered needles. The taper can spread over more than 6 mm while the radius of tip curvature can be decreased down to 30 nm. These needles are strong and were successfully applied for piercing single smooth vascular muscle cells.
我们表明，通过选择合适的金属向金属氧化物和氢氧化物转化的热力学途径，可以控制具有纳米锋利尖端的长探针的电化学形成。目前，广泛使用对流受限电化学抛光（CLE）。通过电化学蚀刻金属丝直到它断裂成两部分来制备纳米锋利探针。由于相关流体动力学的复杂性，这个过程难以控制。我们引入了传输受限电化学抛光（TLE），其中电化学反应导致金属氧化物和氢氧化物的形成，形成阻碍电解质流动的多孔表面层。所开发的 TLE 方法可用于制造长锥形针。锥度可以扩展超过 6 毫米，而尖端曲率半径可以减小到 30nm。这些针非常坚固，并成功地用于刺穿单个光滑的血管平滑肌细胞。
