Robert F. Kennedy and the Indiana Primary – By Ray E. Boomhower

Biocidal Polymers: A Mechanistic Overview

“…were obtained in a subsequent study by Palermo et al, who examined the impact on the antibiotic action through using methyl and butyl methacrylate as comonomers and adjusting their compositions (f alkyl ). 113 Optimal antibiotic activities of the copolymers were observed when increasing the f alkyl , while the HC 50 /MIC of the copolymers was found to monotonically decrease with the f alkyl , indicating the loss of selectivity with increasing hydrophobicity. A subsequent study of the kinetics of liposome dye leakage induced by protonated poly(3-aminopropyl methacrylamide)-co-poly(butyl/hexyl methacrylamide) showed that polymers with high contents of hydrophobic comonomers induced fast leakage of dye, while those with high cationic compositions caused slow leakage.…”

“…Non-quaternized ammonium groups, such as primary and tertiary ammonium groups, are also able to kill germs once they are protonated under a certain pH range. 85 Other common cationic groups (Figure 2) include: pyridinium, 86-88 guanidinium 73,[89][90][91] 12 and biguanide, 92 quaternary phosphonium, 78,[93][94][95] and tertiary sulfonium. 96 The type of polymer backbone used in antibiotic polymers also varies widely.…”

“…Palermo et al compared the antibacterial behavior of antibiotic polymers with protonated primary (poly(2-aminoethyl methacrylate), PAEMA), protonated tertiary (PDMAEMA) and quaternary ammonium groups (alkylated PDMAEMA). 113 It was found that polymers with primary and tertiary amine groups exhibited a higher antibacterial effect and better selectivity than the quaternized counterpart, which required higher hydrophobicity to reach similar antibiotic performance, but may also induce more cytotoxicity. Furthermore, through observing the pH dependence of antibacterial activities, they showed that the increase of pH raises the extent of deprotonation of primary/tertiary amine groups, hydrophobicity of the whole polymer, and subsequently the antibiotic and hemolytic action, but high pH caused reductions of both activities, due to the possibility of forming aggregates caused by high hydrophobicity.…”