Fabrication of High-Aspect-Ratio Nanopores in Polymer Membranes: Analysis of Artifacts by Non-Destructive Testing

Microfluidics is a technology field growing at a high pace which has extended into major areas such as health and agriculture sciences. In these fields, microfluidic devices are employed for analyzing biological samples. Biological structures of interest such as proteins, bacteria, and viruses can be identified with microfluidic detectors. Resistive pulse sensors (RPS) have been long employed for detecting and counting cells. The electric current through a pore is monitored in this method while the target element causes partial and non-permanent obstruction of the pore. Recently, the fabrication of resistive pulse sensors with nanopores (nano-RPS) has been leveraged by advances in micro- and nanofabrication techniques. In this work, a tridimensional numerical model of a nano-RPS is presented. The model validation led to errors lower than 1% highlighting a shift in pore diameter throughout the fabrication steps. The simulated pattern of electric current during translocation events was also found to be in good agreement with experimental data. Moreover, some fabrication defects were examined. The combination of open-pore current and translocation pattern was suggested to be used for assessing parameters such as the diameter and wall smoothness linked to the quality of fabrication processes.