Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi - 221005, India.
ACS Biomater Sci Eng. 2020 May 11;6(5):3055-3069. doi: 10.1021/acsbiomaterials.0c00091. Epub 2020 Apr 17.
Besides the excellent osteoconductivity and biocompatibility of 45S5 bioglass (BG), poor mechanical and electrical properties as well as susceptibility toward bacterial adhesion limit its widespread clinical applications. In this context, the present study investigates the effect of addition of piezoelectric sodium potassium niobate (NaKNbO; NKN) on mechanical, dielectric, and antibacterial response of BG. BG-NKN ( = 0, 10, 20, and 30 vol%) composites were synthesized at 800 °C for 30 min. The phase analyses using spectral techniques revealed the formation of the composite without any reaction between BG and piezoelectric ceramic NKN. The dielectric and electrical measurements were performed over a wide range of temperature (30-500 °C) and frequency (1 Hz-1 MHz) which suggests that space charge and dipolar polarizations are the dominant polarization mechanisms. The complex impedance analyses suggest that the average activation energies for grain and grain boundary resistances for BG-NKN ( = 10, 20, and 30 vol%) composites are 0.59, 0.87, 0.94 and 0.76, 0.93, 1.06 eV, respectively. The issue of bacterial infection has been addressed by electrical polarization of the developed composite samples, at 20 kV for 30 min. Statistical analyses reveal that the viability of Gram-positive () and Gram-negative () bacterial cells has been reduced significantly on positively and negatively charged BG-NKN composite samples, respectively. The qualitative analyses using the Kirby-Bauer test supports the above findings. Nitro blue tetrazolium and lipid peroxide assays were performed to understand the mechanism of such antibacterial response, which suggested that the combined effect of NKN addition and polarization significantly enhances the superoxide production, which kills the bacterial cells. Overall, incorporation of NKN in BG enhances the mechanical, electrical, and dielectric properties as well as improves the antibacterial response of polarized BG-NKN composites.
除了 45S5 生物玻璃（BG）优异的骨传导性和生物相容性外，其较差的机械和电气性能以及易受细菌黏附的特性限制了其广泛的临床应用。在这种情况下，本研究探讨了添加压电钠钾铌酸盐（NaKNbO；NKN）对 BG 的机械、介电和抗菌响应的影响。BG-NKN（=0、10、20 和 30 体积%）复合材料在 800°C 下合成 30 分钟。光谱技术的相分析表明，在 BG 和压电陶瓷 NKN 之间没有反应的情况下形成了复合材料。介电和电气测量在很宽的温度（30-500°C）和频率（1Hz-1MHz）范围内进行，这表明空间电荷和偶极极化是主要的极化机制。复阻抗分析表明，BG-NKN（=10、20 和 30 体积%）复合材料的晶粒和晶界电阻的平均激活能分别为 0.59、0.87、0.94 和 0.76、0.93、1.06eV。通过对开发的复合样品进行 20kV、30 分钟的电极化，解决了细菌感染的问题。统计分析表明，革兰氏阳性（）和革兰氏阴性（）细菌细胞的活力在带正电荷和带负电荷的 BG-NKN 复合样品上分别显著降低。使用 Kirby-Bauer 测试进行的定性分析支持了上述发现。进行了硝基蓝四唑和脂质过氧化物测定，以了解这种抗菌反应的机制，这表明 NKN 添加和极化的综合作用显著增强了超氧化物的产生，从而杀死了细菌细胞。总体而言，NKN 掺入 BG 可提高机械、电气和介电性能，并提高极化 BG-NKN 复合材料的抗菌响应。
