Separation of Proteins and Nanoparticles by Charge and Size with a Tunable Semiconductor Membrane

Abstract

We study the applicability of tunable nanoporous semiconductor membranes made of the heavily doped silicone for separation of nanoparticles and proteins by their size and charge. We demonstrate that this type of membrane can overcome one of the major shortcomings of membrane applications for particle separation: the compromise between membrane selectivity and permeability. The microscopic computational model that we have developed describes the translocation process of filtered objects with the translational-rotational Brownian Dynamics taking into consideration effects from the dielectrophoresis, the electrolyte solution flow, and the self-consistent electrostatic potential distribution within the continuum Poisson-Nernst-Planck approach. Our results indicate that the tunable local electric field arising inside the membrane can effectively control interaction of filtered objects with the nanopore to either block its passage or increase the translocation rate by modulating the electroosmotic flow direction and magnitude. By extracting the membrane permeability from our microscopic simulations, we compute the macroscopic sieving factors and show that the size and charge selectivity of the membrane can be tuned by the applied voltage in the broad range.View Large Image | View Hi-Res Image | Download PowerPoint Slide