Surface Charge Modulated Ionic Conductance of Closed Solid State Nanopore Biosensors

H. Ghosh [1], C. Roychaudhuri [1],
[1] Indian Institute of Engineering Science and Technology (IIEST), Shibpur, Howrah, West Bengal, India
Published in 2015

This paper explores surface charge modulated ionic conductance of closed solid-state nanopores for explaining significant nonlinear length dependent variation in ionic current in such nanopore biosensors with a view to design improved sensors without increasing fabrication cost for biomolecule detection. Although extensive work has been done in modeling open pore conductance, closed nanopores have not been considered. For open pore sensors, electrolyte flow rate adjustment is crucial for maximum target molecule binding, limiting LOD to 1pg/ml. In closed silicon oxide nanoporous structure on silicon substrate, depletion layer capacitance at pore bottom dominates impedance sensing, enabling unique peak frequency based detection selective only to target antigen. Using simulations in COMSOL Multiphysics software, we aim to provide a novel framework for modeling surface charge modulated ionic conductance in closed nanopores.