Green synthesis and characterization of Mg0.93Na0.07O nanoparticles for antimicrobial activity, cytotoxicity and magnetic hyperthermia

We have investigated structural, optical, magnetic, magnetic induction heating, cytotoxicity and antimicrobial properties of 7% Na doped MgO nanoparticles (Mg0.93Na0.07O NPs) synthesized by green self-combustion route using fresh lemon juice as capping and reducing agent. PXRD, FESEM, FEG-TEM, SAED, FTIR and PL analysis confirmed formation of highly crystalline single-phase, -26(+/- 5)nm sized Mg0.93Na0.07O NPs in the NaCl type fcc structure. AFM measurements showed agglomeration of grains. Diffuse reflectance analysis demonstrated maximum reflectance change in the UV & blue color region and wide bandgap of -4.79eV for Mg0.93Na0.07O NPs. 240 nm excited PL emission data exhibited broad emission centered at-389 nm and oxygen vacancies in the MgO lattice. ESR study also revealed presence of F-center type defects in the MgO lattice.VSM measurements established superparamagnetic character of Mg0.93Na0.07O NPs along with some signature of d0 type soft ferromagnetic ordering at RT, which can be well understood in BMP model. Heat generation efficiency of Mg0.93Na0.07O NPs (SAR = 123.5 W/g) is suitable for mild hyperthermia cancer therapy. Mg0.93Na0.07O NPs showed remarkable antibacterial and antifungal activity against few common pathogens. MIC values of Mg0.93Na0.07O NPs against gram-positive S. aureus & S. pyogenes, gram negative E. coli bacteria and C. albicans fungi were found to be comparable to standard drugs. In vitro cytotoxicity of Mg0.93Na0.07O NPs has been tested on normal fibroblast cells and MCF-7 breast cancer cells by MTT assay method, which showed dose dependent response. Findings revealed that cancer cell viability significantly decreases with increasing concentration of Mg0.93Na0.07O NPs, however these nanoparticles also showed considerable toxic effect on normal cells at higher concentration. Antimicrobial activity and cytotoxicity of Mg0.93Na0.07O NPs is attributed to generation of ROS on the surface of nanoparticles. This study demonstrates that greenly synthesized Mg0.93Na0.07O NPs might be suitable for food packaging, bactericide for water purification and biomedical applications.

Automated summary

In this study, 7% Na doped MgO nanoparticles (Mg0.93Na0.07O NPs) were successfully synthesized using a green self-combustion route with fresh lemon juice as a capping and reducing agent. The nanoparticles exhibited high crystallinity, optical and magnetic properties, and showed potential applications in mild hyperthermia cancer therapy, antimicrobial activity, and cytotoxicity. However, they also demonstrated toxic effects on normal cells at higher concentrations.