Immobilization of multivalent antimicrobial peptides onto reverse osmosis polyamide membranes
Supervisor: Dr. Roni Kasher

Abstract:

A major problem encountered in operating reverse osmosis (RO) desalination processes is biofouling, caused by bacterial adhesion and growth on the surface of the membrane.

This research focuses on an alternative approach to prevent biofilm formation on RO membranes, that relies on covalent attachment of multivalent active biomaterials such as antimicrobial peptides to the solid polymeric membranes in a way that preserves the  conformation, and hence the biological activity, of the peptides.

Antimicrobial peptides (AMPs) are components of a living organism’s innate immunity. These peptides are non toxic to humans, have antimicrobial activity against a broad range of bacteria and bacteria cannot easily develop resistance against them. The AMPs mode of action consists of association with the bacterial membrane and its perturbation, which leads to celllysis
We suggest using a multivalent structure, which consists of multiple copies of a peptide attached to a single linker molecule on the RO membrane, to enhance the antimicrobial activity of the peptides.

 

Multivalent antimicrobial peptides attached to the membrane via a reactive polymer linker.

The monomeric AMPs were synthesized via solid phase peptide synthesis (SPPS), using an automated peptide synthesizer and their structure was confirmed by mass spectrometry (MS) and reverse phase high pressure liquid chromatography (HPLC) analysis.

The multivalent structures were synthesized using a reactive polymer or dendrimeric scaffold as the linker molecule. To confirm the structure we used nuclear magnetic resonance (NMR) analysis. The molecular weight distribution of the polymers will be determined by a gel permeation chromatography (GPC) system.

 

So far we have succeeded to prepare a multi-peptide-polymer construct that will be immobilized in subsequent stages onto RO membranes. The antimicrobial activity of the immobilized peptides will be evaluated using a biological assay and then more dendrimers and multivalent constructs will be synthesized to achieve higher activity of the peptides. This work, if successful, will lay the basis for development of a new approach to treat biofouling on RO membranes.