Unexpected Like-Charge Self-Assembly of a Biguanide-based Antimicrobial Polyelectrolyte
Journal: The Journal of Physical Chemistry Letters
Publication Date: 06 September, 2016
Department of: Chemical Engineering and Analytical Science
Simulations help understand bactericide action
Among the most common antimicrobial agents in use, synthetic polycations (PCs) are by far the most promising. Among them, the guanidinium derivative PCs such as polyhexamethyl biguanide, PHMB, show a high bactericide action against a wide spectrum of bacteria. Despite the wide commercialization of guanidinium-based PCs, their mechanism of action is not known and the accepted one, involving the disruption of the bacterial membrane, has been recently questioned.
Researchers at the University of Manchester have recently shown that PHMB is indeed an exceptional polyelectrolyte with unique self-assembly properties. Unlike any other polyelectrolytes, it self-assembles in water also in the presence of monovalent counterions, even at low salt concentrations. The polymer assembles in a compact, ordered, impenetrable hairpin-like shape object stabilized by the like-charge pairing of the biguanide units. This unique self-assembly behaviour may be linked to the antimicrobial properties of the polymer and could help in rationalizing its biological activity. These results also open up the possibility of using PHMB for applications other than antimicrobial solutions, such as structural materials or for nanopattering of surfaces.