POLYMERIC ANTIBIOTICS AGAINST RESISTANT BACTERIA

Cationic polymers have been found as a promising class of antibacterial compounds whose bioactivity can be controlled through structural modification. According to recent research, the cationic groups may be more selective and bioactive for bacterial cells than mammalian cells if they are positioned near the polymeric architecture's core as opposed to on side chains that are appended. However, antibacterial main-chain cationic polymers are often manufactured by polycondensation reactions, which do not allow for precise and uniform molecular design. In order to obtain main-chain cationic polymers with high levels of molecular tunability, controlled polymerizations that tolerate cationic motifs, also known as cation progenitors, close to the propagating species are ultimately necessary. The main-chain cationic polymers' structural diversity and bioactivity may be investigated thanks to the efficient ROMP (ring-opening metathesis polymerization of N-methylpyridinium-fused norbornene monomers) that was achieved by identifying the reaction conditions. With lowest inhibitory concentrations as low as 25 µg/mL, this polyelectrolyte family was found to be active against both Gram-positive (Methicillin-resistant Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Furthermore, it was shown that the polymers' molar masses had an effect on their hemolytic activity, with cationic polymers with lower polymerization degrees demonstrating greater preference for bacteria over human red blood cells.

Utilizing a carefully chosen catalyst known as AquaMet, the Laboratory, operating at the intersection of organic chemistry and polymer science, the team was able to create the novel polymer by meticulously creating a positively charged molecule that can be stitched numerous times to form a large molecule composed of the same repeating charged motif. That catalyst is critical because it must tolerate a high concentration of charges while still being water-soluble – a quality he characterizes as unusual for this type of operation.

The World Health Organization has said that the swift rise of germs resistant to antibiotics poses a worldwide concern and has demanded that new antibiotics be developed immediately. A promising family of bioactive compounds are cationic polymers, which physically damage the membranes of bacteria to cause cell death. Nonetheless, in order to maximize the therapeutic potential of cationic polymers, polymerization processes need to be carefully planned. The  synthesis of main-chain cationic polymers by N-methylpyridinium-fused norbornenes polymerized via controlled ring-opening metathesis. It was discovered that these charged polymers were effective against bacteria that were Gram-positive and -negative. Their preference for bacterial cells over human red blood cells was further enhanced by modifying the pyridinium core and chain length.

REFERENCE:

1.Texas A&M University. "Polymers that can kill bacteria."ScienceDaily.ScienceDaily,22,December,2023. <www.sciencedaily.com/releases/2023/12/231222145359.htm>.

2.Sarah N. Hancock, Nattawut Yuntawattana, Emily Diep, Arunava Maity, An Tran, Jessica D.Schiffman, Quentin Michaudel. Ring-opening metathesis polymerization of N -methylpyridinium-fused norbornenes to access antibacterial main-chain cationic polymers. Proceedings of the National Academy of Sciences, 2023; 120 (51) DOI: 10.1073/pnas.2311396120