Antibacterial properties of cationic copolymers as a function of pendant alkyl chain length and degree of quaternization

Abstract

Antibacterial polymers are promising materials in the fight against bacterial infection which is a vital health problem. Among these materials, cationic (co)polymers with quaternary ammonium groups are of great interest and importance as they interact with the bacterial membrane causing cell death. The antibacterial efficacy can be improved by modifying the pendant alkyl groups and charge density of the polycation. In this study, alkylbromides with different chain lengths were used to obtain quaternized poly(4-vinylpyridine-co-N-vinylpyrrolidone) (P(4VP-co-NVP)) copolymers of various positive charge densities and pendent alkyl chain lengths. While the chemical structures of the produced copolymers were characterized by Fourier transform infrared and 1 H NMR spectroscopy, physicochemical properties such as size and zeta potential were measured by dynamic light scattering spectrometry. It was determined that the zeta potentials and hydrodynamic diameters of the samples vary between +10 and +32 mV and 10 and 16 nm, respectively. The antibacterial activity of the copolymers were tested against Escherichia coli and Staphylococcus aureus bacteria by broth microdilution and standard 'plate' count methods. The results revealed that the antibacterial activity of the copolymers against Escherichia coli can be successfully adjusted through varying the chain length of the alkylating agent (hydrophobic chains) and the degree of quaternization (positive charge density).

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

“…It should be noted that Reillex ion exchange resins are commercial resins based on crosslinked and partially quaternized poly(4-vinylpyridine). Finally, amphiphilic copolymers containing a quaternized PVP block have also been reported [ 40 , 41 , 42 ].…”

Construction of Electrostatic Spinning Membranes Based on Conjugated Hemicyanine Derivatives for Photodynamic Antibacterial Application

“…This may be due to the folding behavior of the hemicyanine derivatives with long chains (C6 and C10) during spinning with PVA, resulting in a smaller nanofiber size than that of C3, which has a three-carbon alkyl chain. 19 The fiber diameter (<200 nm) of Cn/PVA was much smaller than that of conventional polypropylene fibers (1.72 μm) which have been used as protective materials, displaying better potential for microbial interception and filtration. 20 Thermal stability is an important factor in assessing the potential of nanofibers for practical applications.…”

“…Transmission electron microscopy (TEM) images also display the same diameter change tendency (Figure S2). This may be due to the folding behavior of the hemicyanine derivatives with long chains (C6 and C10) during spinning with PVA, resulting in a smaller nanofiber size than that of C3, which has a three-carbon alkyl chain . The fiber diameter (<200 nm) of Cn/PVA was much smaller than that of conventional polypropylene fibers (1.72 μm) which have been used as protective materials, displaying better potential for microbial interception and filtration …”

Genome editing in Acinetobacter baumannii through enhanced natural transformation

“…With this purpose, first, the antibiotic resistance characteristics of the multidrug resistant A. baumannii BAA-747 were assessed to determine the antibiotic selection markers and their efficacy in selecting the delivery of plasmids used for genome editing. Second, the susceptibility of AmpC gene mutant A. baumannii bacteria created by the CRISPR-Cas9 genome editing system to ampicillin, kanamycin, and apramycin antibiotics was determined [25]. In the study, the A. baumannii BAA-747 and AmpC mutant A. baumannii overnight cultures were adjusted to a density range of 0.1-0.2 at OD 600 nm (approximately 1-2 × 10 8 colony forming unit [CFU] mL −1 ) and then diluted to 10 6 CFU mL −1 using Muller Hilton Broth (Merck) through a two-fold dilution series.…”