Multilayer Polyelectrolyte Films Functionalized by Insertion of Defensin: a New Approach to Protection of Implants from Bacterial Colonization

Abstract

Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic surgery. In the present study, we developed a new strategy based on the insertion of an antimicrobial peptide (defensin from Anopheles gambiae mosquitoes) into polyelectrolyte multilayer films built by the alternate deposition of polyanions and polycations. Quartz crystal microbalance and streaming potential measurements were used to follow step by step the construction of the multilayer films and embedding of the defensin within the films. Antimicrobial assays were performed with two strains: Micrococcus luteus (a gram-positive bacterium) and Escherichia coli D22 (a gram-negative bacterium). The inhibition of E. coli D22 growth at the surface of defensin-functionalized films was found to be 98% when 10 antimicrobial peptide layers were inserted in the film architecture. Noticeably, the biofunctionalization could be achieved only when positively charged poly(L-lysine) was the outermost layer of the film. On the basis of the results of bacterial adhesion experiments observed by confocal or electron microscopy, these observations could result from the close interaction of the bacteria with the positively charged ends of the films, which allows defensin to interact with the bacterial membrane structure. These results open new possibilities for the use of such easily built and functionalized architectures onto any type of implantable biomaterial. The modified surfaces are active against microbial infection and represent a novel means of local host protection.

Synthesis of Bioinorganic Antimicrobial Peptide Nanoparticles with Potential Therapeutic Properties

“…In models proposing the antimicrobial mechanism of cationic peptides (e.g., toroidial pore and barrel-stave), a conformationally free form of the peptide is required for insertion and orientation across membrane barriers. 52 While surface-immobilized AMPs have shown to bind to cell surfaces and reduce viability, 53,54 it is likely a fraction of the encapsulated peptide diffused from the particles and this free form of the peptide contributed to the biocidal effect in the assays.…”

Comparison of the adherence of E.Coli and S. Aureus to ten different prosthetic mesh grafts: In vitro experimental study

“…adhered to graft 8. Oxidized regenerated cellulose has antibacterial effects against both these species [30]. S. aureus adhered to PDS in clusters, whereas E. coli adhered individually.…”

Functionalised nanoscale coatings using layer-by-layer assembly for imparting antibacterial properties to polylactide-co-glycolide surfaces

“…It is also applicable to substrates of any shape, it is environmentally-friendly and it allows room temperature processing and low-cost manufacturing [25]. Polyelectrolyte multilayered films have therefore been considered for biomedical application such as capsules for drug delivery [26,27], immunosensing [28], regenerative neurobiology [29], antibacterial and anti fungal protection [30,31]. Despite its potential, LbL has not yet been translated for routine application in the manufacture of medical devices, and further research is required to demonstrate its practical value.…”