Responsive Quaternized PDMAEMA Copolymers with Antimicrobial Action

Abstract

In this work, the antimicrobial action of partially quaternized poly(2-(dimethylamino)ethyl methacrylate) (PQDMAEMA) copolymers using different alkyl halides is presented. The poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) homopolymer was synthesized by group transfer polymerization, followed by the modification of its tertiary amine groups, using bromoethane, iodoethane, bromohexane and bromoethanol, to introduce permanent cationic, quaternary ammonium salt moieties, randomly distributed along the polymer chains. In all cases, the degree of quaternization was low, at ~10 mol%, as verified by proton nuclear magnetic resonance spectroscopy to preserve the thermo-responsive character of the PDMAEMA precursor polymer. The biocidal activity of the lightly quaternized PQDMAEMA copolymers against Escherichia coli and Staphylococcus aureus was evaluated by calculating the minimum inhibitory concentration (MIC) as well as the minimum bactericidal concentration (MBC) of the polymers and by comparing them to the respective values of the precursor non-quaternized PDMAEMA homopolymer. The antibacterial mechanism of action in the solution was studied by zeta potential measurements, scanning electron microscopy and protein leakage tests signifying the disruption of the outer membrane of the bacterial cells to release their periplasmic proteins.

Poly(vinyl pyridine) and Its Quaternized Derivatives: Understanding Their Solvation and Solid State Properties

“…Due to these features, they are widely employed as viscosity and surface modifiers as well as selective adsorbers. Consequently, these materials are useful in various industrial applications, materials and formulations from water treatment [ 7 ], membranes [ 8 , 9 ], sensors [ 10 ] and cosmetics to biomedicine with specific uses in bacterial and viral infections [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ].…”

Antibacterial Effect of Colloidal Suspensions Varying in Silver Nanoparticles and Ions Concentrations

“…Although the exact mechanism of the antibacterial effect of AgNPs has not been entirely clarified, various antibacterial actions have been proposed. Among them, the most common modes of action can be attributed to (i) free silver ions uptake causing interruption of ATP molecules and preventing DNA replication, or (ii) formation of reactive oxygen species by AgNPs, or (iii) direct damage of cell membrane by silver ions [ 8 , 24 ]. It has been generally recognized that AgNPs form holes in the bacterial cell wall, causing increased permeability and cell death.…”

“…MIC and MBC were determined using a broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) protocol, as previously described [24]. Briefly, bacteria were streaked from frozen glycerol stocks onto non selective LB agar plates and incubated overnight at 37 • C. Colonies from the fresh plates were suspended in MH broth and grown at 37 • C in a shaking incubator at 200 rpm.…”

Antibacterial and cytotoxic properties of star-shaped quaternary ammonium-functionalized polymers with different pendant groups

“…Both S-QAR and L-QAR showed the similar tendency of IC 50 depending on the pendant group in the order of QAB > QAM > QAC > QAH, showing a positive correlation with the hydrophilicity of the pendant group. 10,16,35,82 The high chain rigidity of QAB and QAC could also lead to lower cytotoxicity than QAH by hindering their cell attachment and penetration, 79 as discussed above. QAM displayed the lowest selectivity (i.e., IC 50 /MBC <0.1) owing to its lowest antibacterial activity.…”