Coatings combining several defence mechanisms against bacterial infections of hip prostheses

Details

Supervisors

Dupont-Gillain, Christine C. ; Vranckx, Cédric

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

Currently, hip joint arthroplasties are increasing due to the ageing population and lifestyle changes. Prosthetic joint infections constitute a significant risk to the survival of prostheses, exacerbated by the formation of bacterial biofilms on artificial surfaces. Those microbial structures possess inherent resistance properties, rendering their elimination difficult. Common pathogens found in such types of infections are Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). In this context, the objective of the present work is to prevent bacterial infections using antimicrobial coatings. Layer-by-layer (LbL) assembly, a bottom-up method allowing the fabrication of thin multilayer materials, was thus used. It allows the build-up of a coating incorporating multiple defence mechanisms targeting S. aureus and S. epidermidis. Film formation was monitored by quartz crystal microbalance with dissipation monitoring. The multilayers are designed using poly-L-arginine, a positively charged polyelectrolyte (PE), gentamicin, an antibiotic, and bacteriophage. They were selected as building blocks for LbL assembly owing to their known antimicrobial and antibiofilm properties, together with heparin, a negatively charged PE. Direct assembly of gentamicin and bacteriophage was unsuccessful, while poly-L-arginine exhibited high adsorption. To promote the gentamicin immobilization, gentamicin-heparin complexes (GHCs) were formed. These GHCs were characterized and assembled on PE layers, resulting in a much better adsorption. Bacteriophages were chemically modified using biotin moieties with a view to exploit the strong biotin-avidin interaction for LbL assembly. Avidin was successfully assembled with PEs, but subsequent bacteriophage immobilization was not achieved. In conclusion, the immobilization of gentamicin, using GHCs, and of poly-L-arginine was successfully achieved. Further investigations are necessary to characterize the assembled coatings, study their release kinetics in vitro and in vivo, and evaluate antibacterial and antibiofilm properties. This work contributes to the development of strategies aiming at preventing bacterial infection of joint prostheses. It also paves the way for strategies for bacteriophage immobilization in LbL films.