Electret-induced antibacterial response of Mg1-xCaxSi1-xZrxO3 (x = 0–0.4) bioceramics

Abstract

The potential risk of bacteria-induced prosthetic infection during implantation/post-operative healing raises a serious concern about the success of implant/surgery. In this context, the present study successfully established the antibacterial efficacy of the electret form of Mg1-xCaxSi1-xZrxO3 (x = 0, 0.1, 0.2, 0.3, 0.4 [MCSZO-X]) bioceramics, toward both, Escherichia Coli and Staphylococcus aureus bacteria with reference to those of hydroxyapatite (HAP). MCSZO-X bioceramics were synthesized using a solid-state route. The influence of Ca- and Zr co-doping on the crystallite size of MCSZO-X has been analyzed using X-ray peak profile analyses. The electrets were developed by corona poling of sintered MCSZO-X samples at voltage and temperature of 20 kV and 500°C (30 min), respectively. The charge, stored on the surface of MCSZO-X electret samples was calculated to be 0.253, 0.294, 0.320, 0.173, and 0.161 µC/cm2 via thermally stimulated depolarized current measurement. The positive and negative ends of MCSZO- X electrets exhibited a reduction in the viability of E. coli bacteria by (24%, 25%, 30%, 43%, and 42%) and (29%, 37%, 39%, 51%, and 48%), respectively, in comparison to those of HAP. On the contrary, the viability of S. aureus bacteria has decreased by (26%, 33%, 35%, 46%, and 42%) and (21%, 22%, 27%, 395, and 37%) on the surfaces of the positive and negative ends of MCSZO- X electrets, respectively, with the reference of those of HAP. The mechanism of electret-induced antibacterial activity has been revealed via various assays, such as catalase activity, superoxide production (SOD), protein estimation, and lipid peroxidation (LPO) assays. The positive ends of MCSZO-X electrets demonstrate antibacterial efficacy by means of more reactive oxygen species generation as compared to their negative ends of electrets and uncharged surfaces of MCSZO-X samples, as revealed by SOD, protein estimation, catalase activity, and LPO assays. However, the negative ends of electrets prevent the adhesion of bacterial cells via electrostatic repulsion. © 2024 The American Ceramic Society.