Electret‐induced antibacterial response of Mg_1‐xCa_xSi_1‐xZr_xO₃ (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.