Effect of the Medium Composition on the Zn2+ Lixiviation and the Antifouling Properties of a Glass with a High ZnO Content.

Leticia Esteban-Tejeda,Roberto López-Píriz,Francisco Palomares,Ramón Torrecillas,Belén Cabal,José Moya,David Sevillano,Adolfo Fernández,Luis Alou

doi:10.3390/ma10020167

Abstract

The dissolution of an antimicrobial ZnO-glass in the form of powder and in the form of sintered pellets were studied in water, artificial seawater, biological complex media such as common bacterial/yeast growth media (Luria Bertani (LB), yeast extract, tryptone), and human serum. It has been established that the media containing amino acids and proteins produce a high lixiviation of Zn2+ from the glass due to the ability of zinc and zinc oxide to react with amino acids and proteins to form complex organic compounds. The process of Zn2+ lixiviation from the glass network has been studied by X-ray photoelectron spectroscopy (XPS). From these results we can state that the process of lixiviation of Zn2+ from the glass network is similar to the one observed in sodalime glasses, where Na+ is lixiviated to the media first and the fraction of Zn that acts as modifiers (~2/3) is lixiviated in second place. After the subsequent collapse of the outer surface glass layer (about 200–300 nm thick layer) the dissolution process starts again. Antifouling properties against different bacteria (S. epidermidis, S. aureus, P. aeruginosa, E. coli, and M. lutea) have also been established for the glass pellets.

Highlights

Surfaces with antifouling properties to resist the adsorption of microbes are vital in a wide range of biomedical applications, such as in catheters, prosthetic devices, contact lenses, devices for drug delivery, or patterned materials for cell culture [1,2,3,4]
It is well reported in the literature that dissolution of ZnO metal oxide produces metal ions (Zn2+ ) which are known to be responsible for toxicity to bacteria
The X-ray diffraction (XRD) band located at ~30◦ may correspond to the most intense XRD diffraction peak (113) of the Willemite (α-Zn2 SiO4 ) phase (JCPDS file 37-1485) [28]

Summary

Introduction

Surfaces with antifouling properties to resist the adsorption of microbes are vital in a wide range of biomedical applications, such as in catheters, prosthetic devices, contact lenses, devices for drug delivery, or patterned materials for cell culture [1,2,3,4]. Zinc oxide nanoparticles [5] are currently used to functionalize surfaces to investigate their potential ability to reduce biofilm formation on metal and polymer surfaces [6], medical implants [7], and for their oxidative photocatalytic activity to be used in waste-water treatment [8]. It is well reported in the literature that dissolution of ZnO metal oxide produces metal ions (Zn2+ ) which are known to be responsible for toxicity to bacteria. Low ZnO dissolution was observed in aqueous media (Milli-Q and PBS (Phosphate-buffered saline)) without complex organic components

Methods

Results

Conclusion