Impact of Charge Composition and Distribution on the Antibacterial Properties of Polypeptide Coatings

Abstract

Inspired by the charge composition and distribution of proteins and peptides, we designed and prepared a series of brush polypeptides with positive and negative charges separately distributed in the side chains and the backbones. The brush polypeptides can self-or co-deposit on various substrates forming ultrathin and stable coatings. They showed potent bactericidal activity and antibiofilm property, outperforming conventional linear polypeptide coatings with randomly distributed positive and negative charges. Keeping the balance of positive/negative charges and increasing the numbers of positive/negative charges can further improve the antibacterial property of brush polypeptide coatings without sacrificing their biocompatibility.

Brush Polymer Coatings with Hydrophilic Main-Chains for Improving Surface Antibacterial Properties

“…Increasing DS or KE length slightly improved the inhibition of biofilm growth. It is worth mentioning that K 25 E 25 -coated PDMS surfaces showed 30% biofilm growth after 48 h, which is much higher than K 50 E 50 coatings (about 4%) from our recent work . We reasoned that the decreased main-chain length and DA-assisted codeposition method have led to faster biofilm growth on material surfaces since the PDA-coated surfaces have showed increased biofilm growth.…”

“…Recently, bifunctional antibacterial polymer coatings have gained increasing attention for their diversity of chemical and topological structures, development of controlled polymerization methods, and good processability which enable them to possess tunable and desired surface biological properties. − Usually, these coatings are composed of two distinct functional components (e.g., chemical groups or chain segments) with antifouling or bactericidal properties. − Different functional components can be distributed in linear polymers with random or block sequences − or separately distributed in the side-/main-chains to optimize surface biological properties, such as antifouling and bactericidal properties. Previous work has suggested that hydrogen bonding hydration from both pendant groups and main-chains can improve the antifouling property of hydrogels .…”

“…It is widely available, biocompatible, highly hydrophilic, and resistant to protein adsorption and bacterial adhesion. We chose polypeptides as the side-chains because of their widely available starting materials (i.e., α-amino acids), controlled ring-opening polymerization (ROP) methods, and natural-peptide-mimetic structures. − Our recent work has indicated that it is important for antibacterial polymer coatings to keep the balance of positive/negative charges . Therefore, random copolypeptides (i.e., KE) with equivalent l -lysine (K) and l -glutamic acid (E) residues were designed as the side-chains.…”

“…11−13 Usually, these coatings are composed of two distinct functional components (e.g., chemical groups or chain segments) with antifouling or bactericidal properties. 14−17 Different functional components can be distributed in linear polymers with random or block sequences 18−21 or separately distributed in the side-/ main-chains 22 to optimize surface biological properties, such as antifouling and bactericidal properties. Previous work has suggested that hydrogen bonding hydration from both pendant groups and main-chains can improve the antifouling property of hydrogels.…”

“…25−28 Our recent work has indicated that it is important for antibacterial polymer coatings to keep the balance of positive/negative charges. 22 Therefore, random copolypeptides (i.e., KE) with equivalent L-lysine (K) and L-glutamic acid (E) residues were designed as the sidechains. In this contribution, we intended to study the impact of hydrophilic/hydrophobic main-chains, side-chain length, and density and the topological structures on the antibacterial properties of brush polymer coatings.…”