Characterization of hLF1–11 immobilization onto chitosan ultrathin films, and its effects on antimicrobial activity

Abstract

a b s t r a c t hLF1-11 (GRRRRSVQWCA) is an antimicrobial peptide (AMP) with high activity against methicillin-resistant Staphylococcus aureus (MRSA), the most prevalent species in implant-associated infection. In this work, the effect of the surface immobilization on hLF1-11 antimicrobial activity was studied. Immobilization was performed onto chitosan thin films as a model for an implant coating due to its reported osteogenic and antibacterial properties. Chitosan thin films were produced by spin-coating on gold surfaces. hLF1-11 was immobilized onto these films by its C-terminal cysteine in an orientation that exposes the antimicrobial activity-related arginine-rich portion of the peptide. Two levels of exposure (with and without a polyethylene glycol (PEG) spacer) were analyzed. Covalent immobilization was further compared with the AMP physical adsorption onto chitosan films. Surfaces were characterized using ellipsometry, contact angle measurements, atomic force microscopy, infrared and X-ray photoelectron spectroscopies and using a fluorimetric assay for hLF1-11 quantification. Surface antimicrobial activity was assessed through surface adhesion and viability assays using an MRSA (S. aureus ATCC 33591). The incorporation of hLF1-11 increased significantly bacterial adhesion to chitosan films. However, the presence of hLF1-11, namely when immobilized through a PEG spacer, decreased the viability of adherent bacteria with regard to the control surface. These results demonstrated that hLF1-11 after covalent immobilization by its cysteine can maintain activity, particularly if a spacer is applied. However, further studies, exploring the opposite orientation or the same C-terminal orientation, but non-cysteine related, can help to clarify the potential of the hLF1-11 immobilization strategy.

Dhvar5 antimicrobial peptide (AMP) chemoselective covalent immobilization results on higher antiadherence effect than simple physical adsorption

“…This result was expected, since we previously demonstrated the antimicrobial properties of this chitosan ultrathin films [18]. Remarkably, films with adsorbed peptide (Ch_Dhvar5_ads) did not significantly differ from Ti neither from Au in total adhered bacteria, demonstrating that the adsorbed Dhvar5 induced bacterial adhesion to chitosan film.…”

“…Chitosan ultrathin films were produced as previously described [18]. Briefly, commercial squid pen chitosan (France Chitine) was purified by the re-precipitation method [19] resulting on a molecular weight of 283,000-472,000 with a deacetylation degree (DD%) of~85%.…”

“…Functionalization of chitosan thin films with N-acetyl cysteine (NAC), for introduction of SH groups, was previously optimized by Costa et al [18], through employment of carbodiimide chemistry. Briefly, chitosan thin films were treated with a solution of 0.…”

Antibacterial Activity of Ag‐Hydroxyapatite Coating Against Hematogenous Infection by Methicillin‐ResistantStaphylococcus aureusin the Rat Femur

“…Such behavior could represent a good model for bacteremia without ongoing sepsis. Several antibacterial coatings (antibiotics, antiseptics, metal ions, non‐metal ions, or organic molecules) of implants in orthopedics have been developed, and the ability of such implants to minimize bacterial adhesion or inhibit biofilm formation has been investigated. However, we believe that to date, the antibacterial activity against hematogenous infection has not been investigated.…”

Cecropin–Melittin Functionalized Polyurethane Surfaces Prevent Staphylococcus epidermidis Adhesion without Inducing Platelet Adhesion and Activation

“…Although several approaches to create bactericidal coatings (based on different AMPs, substrates and conjugation strategies) have been described, the translation to clinically relevant materials such as polyurethane is still scarce. Yu et al have recently reported a bactericidal antiadhesive coating consisting of a polymer brush conjugated with the AMP E6 on PU, in the context of urinary catheters application .…”