CIN2 (ICN-CSIC), Catalan Institute of Nanotechnology, Campus de la UAB, 08193, Bellaterra (Barcelona), Spain.
Nanoscale. 2011 Aug;3(8):3350-6. doi: 10.1039/c1nr10377f. Epub 2011 Jul 15.
The effect of the AuNPs size, ranging from 5 nm to 80 nm, on the electrochemical response of screen-printed carbon electrodes (SPCEs) used as electrochemical transducers is investigated for the first time. A simple hydrodynamic modelling and calculation at the nanoscale level is applied so as to find the effect of the size of AuNP upon the electrochemical response. The results show that the best electrochemical response for AuNP suspension for the same concentration of total gold is obtained for the 20 nm sized nanoparticles. It is concluded that the Brownian motions avoid a better response for smaller AuNPs that should in fact be related with the best electrochemical signal due to their higher surface area. Finally, the size effect is studied for AuNPs acting as electroactive labels in an immunosensor that employs magnetic beads as platforms of the bioreactions. The best response for the 5 nm AuNPs in this case is due to the fact that in the immunosensing conditions the Brownian motions are minimized because the AuNPs contact with the electrotransducer surface is induced by the immunoreaction and the fast magnetic collection of the nanoparticles used as antibody labels upon application of a magnetic field.
首次研究了金纳米粒子（AuNPs）的尺寸（5nm 至 80nm）对用作电化学换能器的丝网印刷碳电极（SPCE）的电化学响应的影响。应用简单的纳米级流体动力学建模和计算来确定 AuNP 尺寸对电化学响应的影响。结果表明，对于相同总金浓度的 AuNP 悬浮液，20nm 尺寸的纳米粒子获得了最佳的电化学响应。得出的结论是，布朗运动避免了较小 AuNP 获得更好的响应，实际上这与由于其更高的表面积而导致的最佳电化学信号有关。最后，研究了金纳米粒子作为免疫传感器中电活性标记物的尺寸效应，该传感器使用磁性珠作为生物反应的平台。在这种情况下，5nm AuNP 具有最佳的响应，这是因为在免疫传感条件下，布朗运动最小化，因为 AuNP 与电换能器表面的接触是由免疫反应诱导的，并且在施加磁场时，用作抗体标记的纳米粒子快速通过磁场进行收集。
