Combating drug-resistant bacteria with sulfonium cationic poly(methionine)

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Infectious Diseases

Background:

• Antibiotic resistance and drug-resistant bacterial infections present a major global health challenge.
• Antimicrobial peptides (AMPs) show therapeutic potential but face limitations like high cost and protease instability.
• Cationic poly(α-amino acid)s are explored as synthetic AMP mimics, with lysine-based polymers being a notable example.

Purpose of the Study:

• To develop a novel class of synthetic antimicrobial peptide (AMP) mimics.
• To investigate the potential of functional poly(methionine)s as cationic AMP mimics.
• To evaluate the antibacterial activity, biocompatibility, and efficacy of these new mimics against resistant bacteria.

Main Methods:

• Synthesis of sulfonium cationic poly(d,l-methionine)s with varying chain lengths via polymerization of α-amino acid thiocarboxyanhydride (α-NTA).
• Initiation using tert-butyl-benzylamine and subsequent alkylation with iodomethane.
• Assessment of antibacterial activity against antibiotic-resistant strains and biocompatibility with mammalian cells.

Main Results:

• A series of sulfonium cationic poly(methionine)s were successfully synthesized.
• The optimal methionine polymer exhibited potent, broad-spectrum antibacterial activity against resistant bacteria.
• The polymer demonstrated excellent biocompatibility with mammalian cells and rapid bactericidal effects.

Conclusions:

• Sulfonium poly(methionine)s represent a promising new class of synthetic AMP mimics.
• These polymers offer a potential strategy to overcome the challenges posed by drug-resistant bacterial infections.
• The developed materials show potential for future therapeutic applications in combating antimicrobial resistance.