Synthesis and antimicrobial activities of new water‐soluble bis‐quaternary ammonium methacrylate polymers

Abstract

New methacrylate monomers containing pendant quaternary ammonium moieties based on 1,4-diazabicyclo-[2.2.2]-octane (DABCO) were synthesized. The DABCO group contains either a butyl or a hexyl pendant group comprising the hydrophobic segment of the monomers and one tether group to the methacrylate moiety. The monomers were homopolymerized in water by using 2,2Ј-azobis(2-methylpropionamide) dihydrochloride (V-50) as an initiator. The monomers and polymers were characterized by elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), FTIR, and 13 C-NMR. The antimicrobial activities of the corresponding small molecules (bis-quaternary ammonium monocarboxylates) and polymers were investigated against Staphylococcus aureus and Escherichia coli. Although the small molecules did not show any antimicrobial activity, the polymers were moderately effective against both Gram-positive and Gramnegative bacteria. The minimum inhibitory concentration (MIC) values of the polymers with butyl and hexyl hydrocarbon chains against S. aureus and E. coli were found to be 250 and 62.5 g/mL, respectively. The minimum bactericidal concentration (MBC) value for the polymer with the butyl group was higher than 1 mg/mL, whereas the MBC value for the polymer with hexyl group was found to be 62.5 g/mL. Thus, an increase of the alkyl chain length from 4 to 6 significantly increased the antimicrobial activity of the polymer.

Antimicrobial cationic polymers: from structural design to functional control

“…Such effect can be also confirmed by many other research groups based on various systems. 15,33 It should be pointed out that excessively increasing the chain length can bring about two disadvantages. One is that superabundant hydrophobic structures may lead to intense aggregation between the polymers, thus weakening their biocidal activity.…”

Antibacterial activity of nano fabricated polypyrrole by cyclic voltammetry

“…It is believed that they are non volatile, chemically stable, and do not permeate through the skin .As a result, the application of polymers with antibacterial activities will be a major step towards a healthier living. On the other hand, though hundreds of thousands of polymeric compounds have been prepared, few of them were of visible antimicrobial activities [5].…”

Antiviral and Antibacterial Polyurethanes of Various Modalities

“…Immobilized hydrophobic polyQACs based on alkylated polyethylenimine (PEI) exert their antimicrobial action by disrupting cell walls and/or outer membranes of bacteria and fungi [4,[8][9][10][11][12][13]. The addition of long, hydrophobic chains on polyQACs has been correlated with antibacterial activity.…”

“…The cationic sites of the polyQACs are adsorbed onto anionic sites of the cell-wall by electrostatic interaction, and subsequently diffuse through the cell wall and bind to the cell membrane. At this stage, the alkyl chains act as a surfactant, disrupting the cytoplasmic membrane, which results in a release of electrolytes and nucleic materials resulting in the cell death [10,11]. PolyQACs with alkyl chain length between C 6 and C 12 have shown excellent bactericidal activity against both Gram-positive and Gram-negative bacteria [12][13][14].…”