Synthesis,characterization and in vitro activity of a surface-attached antimicrobial cationic peptide |
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| Authors: | Renxun Chen Nerida Cole Mark DP Willcox Josephine Park Riaz Rasul Elizabeth Carter |
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| Institution: | 1. School of Chemistry, University of New South Wales , Sydney , 2052 , Australia;2. Institute for Eye Research , Sydney , 2052 , Australia;3. Vision CRC , Sydney , 2052 , Australia;4. School of Optometry and Vision Science, University of New South Wales , Sydney , 2052 , Australia;5. School of Chemistry, University of New South Wales , Sydney , 2052 , Australia;6. School of Chemistry, University of Sydney , Sydney , 2006 , Australia |
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| Abstract: | Infection associated with implanted biomaterials is common and costly and such infections are extremely resistant to antibiotics and host defenses. Consequently, there is a need to develop surfaces which resist bacterial adhesion and colonization. The broad spectrum synthetic cationic peptide melimine has been covalently linked to a surface via two azide linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA), and the resulting surfaces characterized by X-ray photoelectron spectroscopy and contact angle measurements. The quantity of bound peptide was estimated by a modified Bradford assay. The antimicrobial efficacy of the two melimine-modified surfaces against Pseudomonas aeruginosa and Staphylococcus aureus was compared by scanning electron microscopy (SEM) and fluorescence microscopy. Attachment of melimine via ABA gave an approximately 4-fold greater quantity of melimine bound to the surface than attachment via FNA. Surfaces melimine-modified by either attachment strategy showed significantly reduced bacterial adhesion for both strains of bacteria. P. aeruginosa exposed to ABA–melimine and FNA–melimine surfaces showed marked changes in cell morphology when observed by SEM and a reduction of approximately 15-fold (p < 0.001) in the numbers of adherent bacteria compared to controls. For the ABA–melimine surface there was a 33% increase in cells showing damaged membranes (p = 0.0016) while for FNA–melimine there was no significant difference. For S. aureus there were reductions in bacterial adhesion of approximately 40-fold (p < 0.0001) and 5-fold (p = 0.008) for surfaces modified with melimine via ABA or FNA, respectively. There was an increase in cells showing damaged membranes on ABA–melimine surfaces of approximately 87% (p = 0.001) compared to controls, while for FNA–melimine there was no significant difference observed. The data presented in this study show that melimine has excellent potential for development as a broad spectrum antimicrobial coating for biomaterial surfaces. Further, it was observed that the efficacy of antimicrobial activity is related to the method of attachment. |
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| Keywords: | antimicrobial cationic peptides biomaterial Pseudomonas Staphylococcus |
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