Tertiary alkylamine-functionalized polyaspartamides with potent antibacterial activity

Area of Science:

• Polymer Chemistry
• Antimicrobial Materials
• Drug Discovery

Background:

• Tertiary alkylamines are common in natural products and pharmaceuticals.
• Their use in antibacterial polymers is underexplored.
• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant health threat.

Purpose of the Study:

• To synthesize and evaluate cationic polyaspartamides (PASP-n) with tertiary alkylamine pendants for antibacterial properties.
• To investigate the antibacterial mechanism and resistance potential of these polymers.
• To assess the therapeutic efficacy of the lead polymer against MRSA infections.

Main Methods:

• Synthesis of a series of cationic polyaspartamides (PASP-n) with varying tertiary alkylamine groups.
• Screening of PASP-n against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli.
• Mechanistic studies involving bacterial membrane interaction and component leakage.
• Evaluation of bacterial resistance development over multiple generations.
• In vivo testing for therapeutic potential in MRSA infection models.

Main Results:

• PASP-4, featuring N,N-dibutylamine groups, demonstrated the highest antibacterial activity and selectivity.
• PASP-4 effectively disrupted bacterial membranes by binding to phosphatidylglycerol (POPG).
• This membrane disruption led to cytoplasmic leakage and rapid bacterial killing.
• No significant bacterial resistance developed after 28 generations of repeated exposure.
• PASP-4 showed therapeutic potential in both local and systemic MRSA infection models.

Conclusions:

• Tertiary alkylamine-based polyaspartamides are promising antibacterial agents.
• PASP-4 exhibits potent, broad-spectrum antibacterial activity via membrane disruption.
• This polymer design strategy offers a viable approach to combatting antibiotic-resistant bacteria like MRSA.