Pursuing antifouling performance: Hydrophilic PES-Siloxene membranes for enhanced biological applications

Membranes are widely used in biomedical applications due to their efficient separations necessary for a variety of applications, ranging from pre-treatments to hemofiltration. These membranes often suffer fouling from high-concentration biological components, such as blood plasma proteins, which limits the separation performance. However, at research level, they are commonly tested using much lower feed concentrations that are not representative of real conditions. Developing and testing a membrane under high feed concentrations, analogous to those used during practical applications, its fouling resistance can be more realistically assessed.
In this work, siloxene, an easy-to-synthesise hydrophilic, two-dimensional nanomaterial, was successfully incorporated as a filler into the polyethersulfone (PES) membrane matrix. At optimised filler loadings of 0.15 wt%, porosity rose to 83 %, zeta potential was enhanced to −35.4 mV and high hydrophilicity was achieved with a water contact angle as low as 27°. Pure water permeance increased from 75 to 147 LMHBar, compared to PES, while rejecting ∼99 % bovine serum albumin (BSA). Furthermore, the flux recovery ratio increased from 17 % to 62 %, therefore improving the use of effective membrane area. PES-siloxene membranes showed significant improvement in their capability to cope with concentrated biological feeds analogous to human blood plasma protein concentration: 80 g L−1 BSA solution. PES-Siloxene membranes also superseded the performance of commercial PES “protein-resistant” membrane and functionalised-graphene oxide in an equivalent matrix, highlighted in the literature for its protein antifouling properties. Overall, PES-siloxene MMM results in a low-cost, protein-resistant, and biocompatible membrane that maintains high selectivity suitable for biomedical applications.