Cationic polymeric N-halamines bind onto biofilms and inactivate adherent bacteria

Area of Science:

• Polymer Chemistry
• Antimicrobial Materials
• Biotechnology

Background:

• Development of novel antimicrobial agents is crucial for combating bacterial infections.
• N-halamine compounds offer a promising platform for creating effective biocides.
• Cationic polymers can enhance antimicrobial efficacy and surface adhesion.

Purpose of the Study:

• Synthesize and characterize novel amine-based cationic polymeric N-halamine precursors.
• Evaluate the antibacterial activity of these polymers against Gram-negative and Gram-positive bacteria.
• Investigate the efficacy of these polymers in eradicating pre-formed bacterial biofilms.

Main Methods:

• Copolymerization of 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TMPM) and trimethyl-2-methacryloxyethylammonium chloride (TMAC).
• Chlorine bleach treatment to convert TMPM moieties to N-halamines (Cl-PMPQ).
• Characterization using 1H NMR, FT-IR, UV, and dynamic light scattering (DLS).
• Antibacterial assays against Escherichia coli and Staphylococcus epidermidis, including biofilm eradication studies.
• Zeta potential analysis for adsorption studies and UV analysis for binding kinetics.

Main Results:

• Successfully synthesized a series of Cl-PMPQ copolymers with varying TMPM:TMAC ratios.
• Water-soluble Cl-PMPQ copolymers (with <70 mol% TMPM) exhibited potent antibacterial activity.
• Cl-PMPQ copolymers rapidly adsorbed onto existing bacterial biofilms.
• Complete eradication of adhered bacteria within biofilms was confirmed.
• Binding kinetics of Cl-PMPQ onto biofilms followed a bimodal model.

Conclusions:

• Amine-based cationic polymeric N-halamines are effective against both planktonic bacteria and biofilms.
• The synthesized Cl-PMPQ copolymers demonstrate significant potential as broad-spectrum antimicrobial agents.
• The ability to adsorb and kill bacteria in biofilms highlights their utility in surface disinfection and infection control.