Quarternized Short Polyethylenimine Shows Good Activity against Drug-Resistant Bacteria

The rise in resistant bacteria strains worldwide is proving to be a challenge to the healthcare industry. These “superbugs” are emerging faster than the rate of new antibiotic discovery. This has a heavy impact on medical devices as they are susceptible to biofilm production. Antimicrobial resistance (AMR) causes infections to be difficult to treat, especially postimplantation of a medical device. To prevent bacterial adhesion on devices, various types are coatings are introduced. By binding antibiotics to polymers, an effective adhesive coating on the surface can be created. However, with AMR on the rise, these polymers are losing their efficacy in the application. Another class of antimicrobial polymers with a different mode of mechanism will be explored in this project. Biocidal polymers are effective antimicrobial agents as they rely on the electrostatic interactions between the polymeric charged groups and the charged microbial membrane. Polyethylenimine (PEI) can be modified to achieve a macromolecule containing various charged cationic groups. Quaternizing low-molecular-weight PEI with different alkyl groups of short, long, and aromatic groups will give rise to various structural differences. The structure of the quaternized PEI is characterized, and its antimicrobial activity and compatibility are shown to be remarkably improved.