Composite hydrogel-loaded alumina membranes for nanofluidic molecular filtration

Abstract

In this paper a nanofluidic molecular filtration system based on soft alginate hydrogel fillings and a solid-state alumina support membrane is presented. The electrostatically controlled diffusion is characterized by partition coefficient of the hydrogel and the flux through the composite membrane for positively and negatively charged dye molecules. The partition coefficient of negatively charged fluorescein sodium molecules into the gel is 2 orders of magnitude lower in 1mM KCl solution than that in 1M KCl solution. The molecular transport properties through the hydrogel loaded alumina membrane are solely dominated by the soft nanoporous hydrogel. Such a composite membrane with alginate hydrogel of only 6wt% shows a selectivity of 5 for the separation of bovine serum albumin (BSA) and bovine hemoglobin (BHb) in high ionic strength solution of phosphate-buffered saline (PBS).