Based on previous work focusing on low molecular bioactive compounds [1, 2, 3] herein polyelectrolyte (PEL) based soft coatings at a relevant surgical biomaterial were prepared and loaded with specific bacteriophages (PHAG). The question concerns the antibacterial potential and modalities related to permanent or temporary PHAG loading of such coatings to minimize implant associated infections [4].
PEL coatings at planar model substrates, surgical Kirschner (K-) wires and agar plates can be prepared by consecutive deposition from polycation and polyanion solutions forming alternate PEL multilayers (PEM) as initiated by Decher [5]. PHAG can be either preloaded or postloaded into PEM coatings. Synthetic and biorelated PEL and both streptococcus aureus (S.a.) bacteria and S.a. PHAG were utilized. Analytical methods include FTIR, UV-Vis, CD, DLS, SFM. Results: Defined PEM coatings of poly(ethyleneimine) (PEI) and either poly(acrylic acid) (PAC) [6] or hyaluronic acid grafted with lactic acid (DAC®) were prepared with either PEI, PAC or DAC outermost layer. S.a. PHAG showed higher binding at PEI compared to PAC or DAC terminated PEM. PEM/PHAG coatings at agar plates showed plaque formation towards S.a. bacterial cultures, which was dependent on both the terminating layer and the bound PHAG amount. K-wires with respective PEM/PHAG coatings were implanted into galleria mellonella larvae and infected by bacteria. Generally, K-wires with PEM/PHAG coatings showed higher larvae survival rates compared to blank K-wire controls. Both outermost layer nature and bound PHAG amount affected larvae survival rate, which supports the agar experiments.
PHAG/PEL functionalization of biomaterials based on aqueous systems, biorelated products and low energy consumption is a sustainable antibacterial coating technology to address implant associated infections.
References: [1] Nanomaterials 2016, 6(3), 53(1-21). [2] Polymers 2018, 10(12), 1314. [3] Pharmaceutics 2020, 12, 799. [4] Injury 2017, 48, 599−607. [5] Decher, Hong, Schmitt, Thin Solid Films 1992, 210, 831-835. [6] ACS Appl. Polym. Mater. 2021, 3, 6230−6237.