Contact-Killing Antibacterial Polystyrene Polymerized Using a Quaternized Cationic Initiator

Area of Science:

• Materials Science
• Polymer Chemistry
• Antimicrobial Technology

Background:

• Contact-killing antibacterial materials offer sustained efficacy but are challenging to develop for stable polymers like polystyrene (PS).
• Chemical modification of polystyrene is difficult due to its stable structure, limiting the development of effective antibacterial surfaces.
• Existing antibacterial agents, such as silver, are often leachable and lose activity upon washing.

Purpose of the Study:

• To develop a contact-killing antibacterial polystyrene sheet with sustained activity.
• To investigate the role of surface cationic properties in antibacterial efficacy.
• To evaluate the material's performance against various bacteria, including drug-resistant strains, and its durability after washing.

Main Methods:

• Synthesized polystyrene using 2,2'-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) as a radical initiator.
• Characterized the synthesized polystyrene (ADIP-PS) surface properties, including ζ-potential.
• Assessed antibacterial activity against Gram-positive and Gram-negative bacteria, including drug-resistant strains, before and after washing.
• Performed cytotoxicity tests on L929 cells.

Main Results:

• Polystyrene synthesized with ADIP (ADIP-PS) exhibited significant contact-killing antibacterial activity, unlike polystyrene synthesized with other initiators.
• ADIP-PS possessed a cationic surface, confirmed by ζ-potential measurements, which correlated with its antibacterial properties.
• ADIP-PS maintained antibacterial activity after washing, outperforming silver-containing polystyrene, and demonstrated broad-spectrum efficacy against diverse bacteria.
• Cytotoxicity tests indicated that ADIP-PS sheets were noncytotoxic.

Conclusions:

• The developed ADIP-PS material provides an effective and durable contact-killing antibacterial surface.
• The cationic nature imparted by the ADIP initiator is crucial for the material's sustained antimicrobial activity.
• ADIP-PS presents a promising, easily producible, and non-toxic antimicrobial material for various applications.