Antibacterial and antifungal efficacy of surface functionalized polymeric beads in repeated applications.

A simple method was developed to prepare polymeric microbeads with antibacterial and antifungal properties. The microbeads of approximately spherical shape and narrow size distribution were prepared from a mixture of poly (4-vinyl pyridine) (P4VP) and poly (vinylidene fluoride) (PVDF) by a phase inversion technique and subsequently derivatized with alkyl bromides having 4-10 carbon atoms. The quaternization of the pyridine groups into pyridinium groups confers the surface with highly effective and long-lasting antibacterial and antifungal properties, as shown by the effect on Escherichia coli and Aspergillus niger. Upon contact with the N-alkylated beads, the bacteria and fungal spores are lysed and intracellular constituents leach out into the medium. The efficacy of the alkyl chains in disrupting the cell membrane was investigated. The stability of the functional group and microbiocidal effectiveness of the microbeads in repeated applications was also assessed.