Antimicrobial Properties of Composites of Chitosan-Silver Doped Zeolites

The antimicrobial functionality of composites constituted by chitosan with silver-doped zeolites was developed and characterized. A composite with chitosan particles and silver-doped zeolites was synthesized using an ionic gelation process with sodium tripolyphosphate. The chitosan silver-doped zeolites composite obtained presented sizes up to 5 mu m, while the silver-doped zeolites had an average size between 0.5 mu m and 3.3 mu m. The synthesized chitosan silver-doped zeolites composites, as well as the silver-doped zeolites and the chitosan dissolution, were characterized through X-ray diffraction, Fourier Transform Infrared spectroscopy and scanning electron microscopy. The electro kinetic behaviour of chitosan, silver-doped zeolites and chitosan silver-doped zeolites composite was evaluated under different pH conditions. The antimicrobial activity of the composites was evaluated in terms of minimum inhibitory concentrations and minimum lethal concentrations and the results suggest that the chitosan silver-doped zeolites composites show antimicrobial activity against gram-negative and gram-positive bacteria, Escherichia coli and Staphylococcus aureus, respectively and against Candida albicans. The results here presented support the potential application of the composite of chitosan with silver-doped zeolites in the functionalization of textiles with antimicrobial properties.
Fabio A. P. Scacchetti thanks to the CNPq-Brazil (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-Brasil/National Council of Scientific and Technological Development-Brazil) for the doctoral scholarship (233550/2014-3). Artur Ribeiro and Artur Cavaco-Paulo thanks to the Portuguese Foundation for Science and Technology (FCT) for the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte. This work is also financed by Project UID/CTM/00264/2019 of 2C2T-Centro de Ciencia e Tecnologia Textil, funded by National Founds through FCT/MCTES.