Antimicrobial effects of positively charged surfaces on adhering Gram-positive and Gram-negative bacteria

Abstract

The infection of biomaterials is determined by an interplay of adhesion and surface growth of the infecting organisms. In this study, the antimicrobial effects on adhering bacteria of a positively charged poly(methacrylate) surface (xi potential +12 mV) were compared with those of negatively charged poly(methyl methacrylate) (-12 mV) and a highly negatively charged poly(methacrylate) (-18 mV) surface. Initial adhesion of Staphylococcus aureus ATCC 12600, Staphylococcus epidermidis HBH(2) 102, Escherichia coli O2K2 and Pseudomonas aeruginosa AK1 to these surfaces was measured in a parallel plate flow chamber in phosphate-buffered saline. Adhering bacteria were allowed to multiply by perfusing the flow chamber with growth medium. All bacteria adhered most rapidly to the positively charged surface, but there was no subsequent surface growth of the Gram-negative strains. On the negatively charged surfaces, despite a slower initial adhesion, surface growth of the adhering bacteria was exponential for both Gram-positive and Gram-negative strains. These results suggest that positively charged biomaterial surfaces exert an antimicrobial effect on adhering Gram-negative bacteria, but not on Gram-positive ones.

Plasma-Generated Poly(allyl alcohol) Antifouling Coatings for Cellular Attachment

“…These assignments are summarized in Table 3. Bacterial adhesion to surfaces, and subsequent biofilm growth, is facilitated by biospecific (protein-protein, carbohydrate-protein) and non-specific (hydrophobic or electrostatic) surface interactions of pili and flagella [29,39].…”

Antimicrobial cationic polymers: from structural design to functional control

“…Cationic groups are the ones that facilitate the adsorption of antimicrobial cationic polymers to the surface of microbial membranes. There are several choices that bear the cationic centers, including ammonium ions, [14][15][16][17] sulfonium ions, 18 phosphonium ions 19,20 and so forth. This section mainly focuses on ammonium-based and iminium-based cationic groups because of their simple syntheses and broad usages.…”

Bacterial Stress and Osteoblast Responses on Graphene Oxide-Hydroxyapatite Electrodeposited on Titanium Dioxide Nanotube Arrays

“…This may be due to the greater resistance of E. coli in direct contact with the edge of the GO compared with S. aureus. Although S. aureus is a Gram-positive bacteria whose peptidoglycan layer provides additional strength to the cell wall, which is also thicker (20-80 nm) than that of E. coli (Gram-negative) bacteria (7-8 nm) [9,24,25], the S. aureus was less resistant than E. coli. Gram-negative E. coli has a much thinner layer of peptidoglycan, but it also has a layer of lipopolysaccharides that might protect the cell.…”

“…Mafu et al reported that the first and the most important such force was the electrostatic force of charges between the surface substrate and bacterial membrane [29]. They show that GO being negatively charged due to the presence of carboxyl, hydroxyl, and epoxy groups is less repulsive to Gram-positive bacteria than Gram-negative bacteria [25].…”