Simple and versatile method for creation of non-leaching antimicrobial surfaces based on cross-linked alkylated polyethyleneimine derivatives

•Glycol dichloroacetates are the best cross-linkers for non-leaching QPEI preparation.•Octyl bromide is optimal alkylating agent for preparation of antimicrobial QPEI.•MeI has no advantages compared to dimethyl sulfate for quaternization of PEI.•Resistance of QPEI to be washed out growths with increase of alkyl chain length.

Novel quaternized polyethyleneimine and cross-linked polyethyleneimine derivatives have been synthesized using both traditional and microwave-assisted techniques to create antimicrobial coatings, with octyl, dodecyl, or hexadecyl bromides as alkylating agent and various bifunctional electrophiles as cross-linkers. Quaternization has been performed using methyl iodide or dimethyl sulfate; it has been shown that methyl iodide has no advantages over dimethyl sulfate. Antimicrobial activity of the polymers against Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria has been evaluated. Antimicrobial activity declines with increase in the alkylating agent chain length. Equimolar ratio of the alkylating agent and the primary amino groups in polyethyleneimine is optimal. Although cross-linking decreases the antimicrobial activity of quaternized polyethyleneimines, it improves their “non-leaching” properties (i.e. minimizes undesirable water washout of the polymeric coatings).