Titanium dioxide (TiO2) nanoparticles (NPs) are among the most extensively utilized metallic oxide nanoparticles. Whether in their pure state or modified with polymers or with other metals, TiO2 NPs plays an essential role. Nevertheless, the modification of size and shape through doping leads to enhancements in the physical, chemical, and biological characteristics of TiO2 nanoparticles. TiO2 NPs have attracted significant interest in biological research because of their distinct characteristics and wide-ranging applications. Researchers have established unique impacts of diverse TiO2 nanostructures, such as nanoparticles, nanopores, nanorods, and nanotubes, in many areas of biotechnology. There has been a remarkable increase in studies on TiO2 NPs due to their chemical stability, low toxicity, and diverse characteristics. These nanoparticles have an essential function in advancing the field of nanomedicine by enhancing nanotechnology through immobilizing biomolecules. They have applications in drug delivery systems, cancer therapy, bone/dental implants, and antibacterial agents. They have also shown potential in biosensors, detecting specific biomolecules with exceptional sensitivity. Therefore, this chapter presents continuing studies about the multifaceted roles of TiO2 NPs in biological systems, emphasizing their impact on human health and potential for advancing nanomedicine have been comprehensively discussed.