Nano-biotechnology deals with the role of biological species in the field of nanotechnology and has gained significant attention in the last few decades. Nano-sized materials have superior physical, chemical, optical, electrical and mechanical properties in comparison with the bulk materials. A number of techniques have been employed so far to synthesize nano-structured materials, and among these, bio-inspired methods are found to be economically viable and environmentally sustainable. Titanium dioxide (TiO 2 ) is one of the most abundant and nontoxic transition metal oxides with high thermal stability, good oxidation and corrosion resistance, good hydrophobicity and non-wettability. All these properties along with a wide band gap make TiO 2 an important material for various applications in the fields of solar cells, sensors, batteries, and supercapacitors. In this review work, a comprehensive study has been carried out on the synthesis of TiO 2 nanoparticles (NPs) using different biological extracts and applications of TiO 2 NPs in the design and development of various electronic devices. KeywordsTiO 2 NPs • bio-fabrication • solar cells • lithium-ion batteries • supercapacitor • sensor * Jagannath Roy