Functional Ag‐Exchanged Zeolites as Biocide Agents

Abstract

Materials based on silver are used for controlling different pathogenic microorganisms. However, the influence of the silver carrier in the biocidal activity of the material has been scarcely reported. The present research is focused on studying the influence of zeolite properties on the biocidal activity of silver‐exchanged zeolites, acting as reservoirs of silver species. The biocidal action of Ag‐Faujasite (Ag‐FAU) and Ag‐Linde Type A (Ag‐LTA) zeolites, containing different silver contents, is studied against different types of bacteria and fungi. Importantly, zeolite structure is found to be a significant parameter for controlling the antibacterial activity of Ag‐exchanged zeolites. The results show that Ag‐FAU presents a higher activity than Ag‐LTA, because the topology of FAU combined with its highest Si/Al ratio favors the formation and release of silver species with important biocidal activity. Some insights on the bactericidal mechanism of Ag‐zeolites are envisaged by means of high resolution transmission electron microscopy, showing the multi‐targeted biocidal action of Ag species released from zeolites. Besides, it is shown that Ag‐zeolites are more active against bacteria than fungi. Antifungal activity is highly dependent on the fungi species and the structure of the zeolite is not as determinant as it is for the antibacterial activity.

Sintesis aditif antimikroba Ag/Zn-zeolit dalam bahan pelapis polivinil asetat

“…Zeolit A dan zeolite faujasite (X dan Y) yang dimodifikasi dengan perak, mampu menangkal mikroba seperti bakteri dan jamur (Cerrillo et al, 2018) Zeolit A yang dimodifikasi dengan Ag+ dan Cu2+ menghasilkan aktivitas antimikroba yang cukup tinggi dan sifat termal yang baik (Yeasmin et al, 2019).…”

“…Dengan adanya zona hambat yang dihasilkan dari setiap variasi menunjukkan bahwa Ag-Zeolit alam sebagai aditif antimikroba dalam PVAc memiliki kemampuan dapat menghambat pertumbuhan bakteri E. coli. Hal ini dikarenakan perak merupakan bahan aktif yang terkandung dalam aditif antimikroba sehingga mampu menghambat pertumbuhan mikroorganisme walaupun pada konsentrasi yang rendah (Cerrillo et al, 2018). Coating dengan kandungan 1% Zn-zeolit dalam larutan polivinil asetat tidak menunjukkan adanya zona penghambatan karena agen antimikroba yang terkandung belum cukup untuk menghambat pertumbuhan bakteri.…”

Comparison of the Antimicrobial and Hemolytic Activities of Various Forms of Silver (Ions, Nanoparticles, Bioconjugates) Stabilized in a Zeolite Matrix

“…Zeolites modified with nanoparticles and silver ions have already been studied. ,,− The appearance of antimicrobial and catalytic activity in modified zeolites was noted. However, the study of zeolites with the same silver content in various forms (in the form of ions, nanoparticles, and bioconjugates), which allows a quantitative and qualitative comparison of their biological activity (using the example of antimicrobial and hemolytic activity, as well as cytotoxicity), excluding the effect of a stabilizer, has not been reported earlier.…”

Silver exchanged zeolites as bactericidal additives in polymeric materials

“…The biocide effects of silver are evident and 0.001 ppm of Ag + cations are effective in controlling bacteria populations, but at the same time, they present low toxicity for eukaryotic cells [16,17]. It has been evidenced the multiple attack of Ag species on different bacteria organelles [18,19], but the biocide mechanism of Ag + cations is not yet fully understood [20].…”

“…Zeolites present cation exchange capacity, permitting to incorporate cations inside zeolitic porous and channels and controlling their release [25]. Ag-zeolites have been studied as supported biocide substances by different authors at in vitro experiments against bacteria, virus and fungi [3,10,18,[26][27][28][29][30][31] and most of these studies showed a correlation between the biocide effects and the lixiviation of Ag [32]. However, for practical uses, the Ag-containing zeolite must be incorporated in final devices.…”