Microfiltration membranes modified by silver-decorated biomimetic silica nanopollens for mitigating biofouling: Synergetic effects of nanopollens and silver nanoparticles

Applications of membrane technologies for water and wastewater treatment call for antibiofouling membranes. Inspired by nature's spiky topological features of pollen grains, we developed silver-decorated biomimetic silica nanopollens (SNPs) to modify a polyvinylidene fluoride microfiltration membrane. The modified membrane demonstrated compelling antibiofouling performance compared to the pristine membrane, which was attributed to the synergetic effects of SNPs and loaded silver nanoparticles. The surface spikes of SNPs could act as multiple 'entry claws' to bind to the cell membrane upon contact, inducing physical deformation and metabolic disturbance of cells. More importantly, the SNPs could serve as a delivery vector for silver ions that were released from silver nanoparticles loaded in SNPs, further leading to cell damage due to the generation of reactive oxygen species and respiratory inhibition. These synergetic effects of SNPs and loaded silver nanoparticles imparted the modified membrane with potent antibiofouling behavior both in batch and continuous flow tests using model bacteria, Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), respectively. Our strategy provides a novel pathway using biomimetic materials to fabricate antibiofouling membranes for water and wastewater treatment.