Engineering of Antimicrobial Surfaces by Using Temporin Analogs to Tune the Biocidal/antiadhesive Effect.

Pierre-Carl Oger,Christophe Piesse,Ali Ladram,Vincent Humblot

doi:10.3390/molecules24040814

Abstract

Proliferation of resistant bacteria on biomaterials is a major problem leading to nosocomial infections. Due to their broad-spectrum activity and their ability to disrupt bacterial membranes through a rapid membranolytic mechanism, antimicrobial peptides (AMPs) are less susceptible to the development of bacterial resistance and therefore represent good candidates for surface coating strategies to prevent biofilm formation. In this study, we report on the covalent immobilization of temporin-SHa, a small hydrophobic and low cationic antimicrobial peptide exhibiting broad-spectrum activity, and (SHa) analogs on modified gold surfaces. Several analogs derived from SHa with either a carboxamidated ([K3]SHa, d-[K3]SHa) or a carboxylated C-terminus ([K3]SHa-COOH) were used to achieve peptide grafting on gold surfaces modified by a thiolated self-assembled monolayer (SAM). Surface functionalization was characterized by polarization modulation infrared reflection absorption spectroscopy (PM-RAIRS) and X-ray photoemission spectroscopy (XPS). The antibacterial properties of the temporin-functionalized surfaces were tested against the Gram-positive Listeria ivanovii. Direct visualization of the peptide effects on the bacterial membrane was investigated by scanning electron microscopy equipped with a field emission gun (SEM-FEG). All active temporin analogs were successfully grafted and display significant antibacterial activity (from 80 to 90% killing efficiency) in addition to a 2-fold decrease of bacterial adhesion when all d-SHa analogs were used.

Highlights

More than 70 years ago, the scientific community described for the first time bacterial contaminations on surfaces that later would be named biofilms [1]
We have investigated the functionalization of gold surfaces with another family of short antimicrobial peptides (AMPs), the temporins, and with temporin-SHa (SHa) [21]
We first investigated the antimicrobial activity of temporin analogs by determining minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) against a inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) against a GramGram-positive bacterial strain, Listeria ivanovii (Li4pVS2)

Summary

Introduction

More than 70 years ago, the scientific community described for the first time bacterial contaminations on surfaces that later would be named biofilms [1]. A biofilm is a more or less complex multicellular community, often composed of symbiotic microorganisms (such as bacteria, fungi and algae) adhering to a surface or together as aggregates, and characterized by the secretion of a protective and adhesive matrix. Biofilms generally form in water or in an aqueous medium [3]. The biofilm matrix usually encapsulates and protects the embedded bacteria, conferring high resistance to surrounding stresses [4]. The biofilm is a potentially normal step of the life cycle of most bacteria, displaying cooperative behavior and producing differentiated phenotypes that lead to specific functions, sometimes in response to stress [5]

Results

Discussion

Conclusion