title: High-density antimicrobial peptide coating with broad activity and low cytotoxicity against human cells.
abstract: Medical device-associated infections are a multi-billion dollar burden for the worldwide healthcare systems. The modification of medical devices with non-leaching coatings capable of killing microorganisms on contact is one of the strategies being investigated to prevent microorganism colonization. Here we developed a robust antimicrobial coating based on the chemical immobilization of the antimicrobial peptide (AMP), cecropin-melittin (CM), on gold nanoparticles coated surfaces. The concentration of AMP immobilized (110 μg/cm(2)) was higher than most of the studies reported so far (<10 μg/cm(2)). This translated onto a coating with high antimicrobial activity against Gram positive and negative bacteria sp., as well as multi-drug resistant bacteria. Studies with E. coli reporter bacteria showed that these coatings induced the permeability of the outer membrane of bacteria in less than 5 min and the inner membrane in approximately 20 min. Importantly, the antimicrobial properties of the coating are maintained in the presence of 20% (v/v) human serum, and have low probability to induce bacteria resistance. We further show that coatings have low toxicity against human endothelial and fibroblast cells and is hemocompatible since it does not induce platelet and complement activation. The antimicrobial coating described here may be promising to prevent medical device-associated infections.
  
  
  CONCLUSIONS
  In recent years, antimicrobial peptides (AMPs) have been chemically immobilized on surfaces of medical devices to render them with antimicrobial properties. Surfaces having immobilized cationic peptides are susceptible to be adsorbed by plasma proteins with the subsequent loss of antimicrobial activity. Furthermore, with the exception of very few studies that have determined the cytotoxicity of surfaces in mammalian cells, the effect of the immobilized AMP on human cells is relatively unknown. Here we report a coating based on cecropin-melittin peptide (CM) that maintains its antimicrobial activity against Gram-positive and negative bacteria including multi-drugs resistance bacteria in the presence of serum and has relatively low cytotoxicity against human cells. The reported coatings may be translated on to variety of substrates (glass and titanium) and medical devices to prevent device-associated microbial infection.
authors.affiliation: CNC-Center for Neurosciences and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Biocant, Biotechnology Innovation Center, 3060-197 Cantanhede, Portugal.
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Rai
authors.affiliation: CNC-Center for Neurosciences and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Biocant, Biotechnology Innovation Center, 3060-197 Cantanhede, Portugal.
authors.forename: Sandra
authors.initials: S
authors.lastname: Pinto
authors.affiliation: CNC-Center for Neurosciences and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Biocant, Biotechnology Innovation Center, 3060-197 Cantanhede, Portugal.
authors.forename: Marta B
authors.initials: MB
authors.lastname: Evangelista
authors.affiliation: CIEPQPF, Department of Chemical Engineering, University of Coimbra, 3030-790 Coimbra, Portugal.
authors.forename: Helena
authors.initials: H
authors.lastname: Gil
authors.affiliation: DEMaC/CICECO, Department of Materials and Ceramics Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Silvar
authors.initials: S
authors.lastname: Kallip
authors.affiliation: DEMaC/CICECO, Department of Materials and Ceramics Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Mario G S
authors.initials: MG
authors.lastname: Ferreira
authors.affiliation: CNC-Center for Neurosciences and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Biocant, Biotechnology Innovation Center, 3060-197 Cantanhede, Portugal. Electronic address: lino@biocant.pt.
authors.forename: Lino
authors.initials: L
authors.lastname: Ferreira
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D054807:Cecropins / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006046:Gold / Q000494:pharmacology; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D055767:Immobilized Proteins / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000494:pharmacology*; D056951:Photoelectron Spectroscopy; D044967:Serum / Q000378:metabolism; D013499:Surface Properties
chemical_list: D000890:Anti-Infective Agents; D054807:Cecropins; D020099:Coated Materials, Biocompatible; D055767:Immobilized Proteins; D010455:Peptides; D006046:Gold
keywords: Antimicrobial peptide; Antimicrobial properties; Au NPs-coated surface; Biocompatibility; Cecropin melittin; Nanoparticles