Long before we recognized how significant they were, nanoparticles were already all around in the environment. Since then, an extensive number of synthetic nanoparticles have been engineered to improve our quality of life through rigorous scientific research on their uses in practically every industry, including semiconductor devices, food, medicine, and agriculture. The extensive usage of nanoparticles in commodities that come into proximity with human skin and internal organs through medicine has raised significant concerns over the years. TiO2 nanoparticles (NPs) are widely employed in a wide range of industries, such as cosmetics and food packaging. The interaction and internalization of TiO2 NPs in living cells have been studied by the scientific community for many years. In the present study, we investigated the cell viability, nanomechanical characteristics, and fluorescence response of NIH-3T3 cells treated with sterile DMEM TiO2 nanoparticle solution using a liquid-mode atomic force microscope and a fluorescence microscope. Two different sorts of response systems have been observed in the cells depending on the size of the NPs. TiO2 nanoparticles smaller than 100nm support its initial stages cell viability, and cells internalize and metabolize NPs. In contrast, bigger TiO2 NPs (> 100nm) are not completely metabolized and cannot impair cell survival. Furthermore, bigger NPs above 100nm could not be digested by the cells, therefore hindering cell development, whereas below 100nm TiO2 stimulated uncontrolled cell growth akin to cancerous type cells. The cytoskeleton softens as a result of particle internalization, as seen by the nanomechanical characteristics of the nanoparticletreated cells. According to our investigations, TiO2 smaller than 100nm facilitates unintended cancer cell proliferation, whereas larger NPs ultimately suppress cell growth. Before being incorporated into commercial products, similar effects or repercussions that could result from employing different NPs should be carefully examined.