An overview on biomedical applications of versatile silica nanoparticles, synthesized via several chemical and biological routes: A review

Abstract Silica has drawn the attention of many researchers from all over the world owing to its excellent biological, mechanical, and physiochemical properties. Different synthetic routes, reagents, characterization techniques, and applications of silica nanoparticles (SiO2 NPs) are discussed in this review article. A detailed discussion on sol-gel, ultrasonication, chemical precipitation, and hydrothermal route is presented. Biological synthesis of SiO2 NPs from bamboo leaves, rice husk, and sugarcane bagasse is also focused. Different characterization techniques including X-ray diffraction, dynamic light scattering, transmission electron microscopy, and Fourier transform infrared spectroscopy are discussed in detail. A study on SiO2 NPs conjugated with metallic oxides and polymers is also discussed. Being important materials with a wide variety and novel applications, these conjugates are used in agriculture, mechanical engineering, material science, electronics, and biomedical engineering. However, greater emphasis has been laid on biomedical aspects, including antibacterial applications and drug delivery along with its cytotoxic properties. The review article reflects that SiO2 NPs are potential candidates for several biomedical applications due to their biocompatibility and appreciable biological activity. Graphical Abstract