在我们意识到纳米颗粒的重要性之前，它们已经广泛存在于环境中。自那时以来，通过对几乎每个行业中使用的合成纳米颗粒进行严格的科学研究，我们已经设计出了大量的合成纳米颗粒，以提高我们的生活质量，包括半导体设备、食品、医药和农业。多年来，人们对与人体皮肤和内部器官接触的商品中纳米颗粒的广泛使用产生了重大担忧。TiO2纳米颗粒被广泛应用于化妆品和食品包装等多个行业。科学界多年来一直研究TiO2纳米颗粒在活细胞中的相互作用和内吞。在本研究中，我们使用液体模式原子力显微镜和荧光显微镜，研究了经过灭菌的DMEM TiO2纳米颗粒溶液处理的NIH-3T3细胞的细胞存活能力、纳米机械特性和荧光响应。根据纳米颗粒的尺寸，细胞中观察到了两种不同的反应系统。小于100 nm的TiO2纳米颗粒有利于细胞存活的初期阶段，细胞会内吞和代谢这些颗粒。相反，大于100 nm的TiO2纳米颗粒不能完全代谢，也不能损害细胞存活。此外，大于100 nm的纳米颗粒不能被细胞消化，从而阻碍细胞发育，而小于100 nm的TiO2纳米颗粒则会刺激类癌症细胞类似的细胞不受控制地生长。纳米颗粒处理后，细胞的纳米机械特性显示细胞骨架变软。根据我们的研究，小于100 nm的TiO2颗粒促进了意想不到的癌细胞增殖，而更大的纳米颗粒最终抑制了细胞的生长。在纳入商业产品之前，应仔细研究不同纳米颗粒使用过程中可能产生的类似效应或后果。©2023作者（们），根据Springer-Verlag GmbH Germany的独家许可，Springer Nature的一部分。

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 100 nm support its initial stages cell viability, and cells internalize and metabolize NPs. In contrast, bigger TiO2 NPs (> 100 nm) are not completely metabolized and cannot impair cell survival. Furthermore, bigger NPs above 100 nm could not be digested by the cells, therefore hindering cell development, whereas below 100 nm 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 nanoparticle treated cells. According to our investigations, TiO2 smaller than 100 nm 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.© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.