Effects of electrolyte concentration and electrodes voltage on the minimal distance between 2 electrodes for nanometric-scale biosensors


  Mayan Rousso  ,  Tali Dotan  ,  Yosi Shacham  
Tel Aviv Youth University, Tel Aviv University, Tel Aviv, Israel
Department of Physical Electronics, Faculty of Engineeringg, Tel Aviv University, Tel Aviv, Israel

Biosensors are sensitive analytical devices which are used to detect the presence or concentration of materials in a biological environment.
In recent years, thanks to the development of the miniaturization, researchers started to create nano-scale electrodes, which can potentially be used for biosensors. There are known theories and equations that model the electrical behavior of the electrode environment, which were developed in millimetric and sub-millimetric scale. However, recent studies have shown that the electrical behavior of nanometric scale environment might be different from that of larger scale, probably because the electrodes dimensions and separation are of similar order of magnitude as the effective typical distance. This raises the question of whether the electrode miniaturization affects the desired distance needed between 2 electrodes.
The research was based on a 1D simulation along the radius of a section of an electrode with a radius of 1┬Ám in an ionic solution. The simulation evaluates the electrical potential along a nanometric distance from the electrode surface for variable initial electrode voltage values and for variable solution concentration values. Data was collected and analyzed for multiple definitions of the required distance between 2 electrodes. The connection between the required distance and the voltage values and concentration values was explored.
The distance dependency on solution concentration was statistically significant (P<0.05), and it was observed that the smaller the concentration, the required distance between 2 electrodes becomes greater. The results did not observe statistically significant relationship with the initial voltage (within the range analyzed).
The present study provides additional observation for optimizing future use of nanometric electrodes arrays for biosensors and adjusting the electrodes design for the different required concentrations in the expected biological environments (e.g. in agriculture, in animals and in human).