Mitigation of Biofilm Development on Thin-Film Composite Membranes Functionalized with Zwitterionic Polymers and Silver Nanoparticles

Abstract

We demonstrate the functionalization of thin-film composite membranes with zwitterionic polymers and silver nanoparticles (AgNPs) for combating biofouling. Combining hydrophilic zwitterionic polymer brushes and biocidal AgNPs endows the membrane with dual functionality: antiadhesion and bacterial inactivation. An atom transfer radical polymerization (ATRP) reaction is used to graft zwitterionic poly(sulfobetaine methacrylate) (PSBMA) brushes to the membrane surface, while AgNPs are synthesized in situ through chemical reduction of silver. Two different membrane architectures (Ag-PSBMA and PSBMA-Ag TFC) are developed according to the sequence AgNPs, and PSBMA brushes are grafted on the membrane surface. A static adhesion assay shows that both modified membranes significantly reduced the adsorption of proteins, which served as a model organic foulant. However, improved antimicrobial activity is observed for PSBMA-Ag TFC (i.e., AgNPs on top of the polymer brush) in comparison to the Ag-PSBMA TFC membrane (i.e., polymer brush on top of AgNPs), indicating that architecture of the antifouling layer is an important factor in the design of zwitterion-silver membranes. Confocal laser scanning microscopy (CLSM) imaging indicated that PSBMA-Ag TFC membranes effectively inhibit biofilm formation under dynamic cross-flow membrane biofouling tests. Finally, we demonstrate the regeneration of AgNPs on the membrane after depletion of silver from the surface of the PSBMA-Ag TFC membrane.

Enhanced antibacterial activity through the controlled alignment of graphene oxide nanosheets

“…A cfu enumeration assay was used to evaluate the antibacterial activity of GO composite films, following the protocol developed in previous studies (13,32,34). Cells were exposed to films as described for the live/dead assay.…”

“…To further probe their relative cytotoxicity, GO films were contacted with E. coli and colony-forming units (cfu) of bacteria attached to the surface were enumerated. Briefly, after the bacteria exposure, attached live cells on the films were detached from the surface by mild sonication in saline solution, and subsequently cultured on solid media and incubated overnight (13,32,34). Note that for these experiments, cfu data are influenced not only by cytotoxicity but also by the ability of bacteria to adhere to the surface.…”

In-Situ Surface Modification of Terpinen-4-ol Plasma Polymers for Increased Antibacterial Activity

“…Surfaces functionalized with enzymes, antibiotics and biocides have also been used in the effort to combat microbial attachment [11][12][13]. Hydrophilic/hydrophobic modification and immobilization of nanoparticles (Nps), such as Cu, ZnO, and Ag, onto the surface of material have been used separately as an effective strategy to reduce biofilm formation [14][15][16][17][18]. Surfaces modified to display hydrophilic behavior have shown superior antifouling properties [19][20][21].…”

1,3‐Diamino‐2‐propanol or 2‐aminoethanethiol modified active layer of thin‐film composite forward osmosis membrane

“…So recently, there have been many reports on the modification of active layers . For example, hydrophilic polymers, zwitterionic polymers, ethanediamine (EDA), poly(ethylene glycol) dimethyl ether (PEGDE), JEFFAMINE, porphyrin (Por), NH 2 ‐titanate nanotubes (TNTs), metal organic framework (MOF) materials , or other polymer materials had been grafted onto the membrane. Modifying the active layer is a common method of improving the properties of the TFC film.…”