Single walled carbon nanotubes (SWCNTs) are utilized in many areas, accompanied with the ever rising safety concerns. Coating the SWCNTs by serum albumin has shown promises in reduction of their cytotoxicity. The cause of toxicity reduction could be due to the blockage of cellular protein adsorption by bovine serum albumin (BSA). Here, our study explored the mechanism of toxicity reduction from the point of view of protein adsorption. Different loadings of BSA led to varied surface coverage of the SWCNTs, which was positively related to the level of cytotoxicity. In addition, the BSA-coated SWCNTs were tested for their surface morphology change, cellular uptake, and adsorption of cellular proteins. BSA could be competed off the SWCNT surface by the cytosol proteins, and thus a higher BSA loading was needed to provide better protection to the cells. Cellular uptake was also reduced with a higher BSA loading. Moreover, the BSA coating changed the surface property of SWCNTs, and as a consequence, altered the types of proteins adsorbed by the SWCNTs. Our results support that adsorption of BSA reduces cellular uptake of SWCNTs as well as adsorption of cellular proteins on SWCNTs, both contributing to the much lower cytotoxicity observed for the BSA-coated SWCNTs.

中文翻译：

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白蛋白涂层降低单壁碳纳米管诱导的细胞毒性的机理研究

单壁碳纳米管（SWCNT）在许多领域都有应用，但安全问题也日益突出。用血清白蛋白涂覆单壁碳纳米管有望降低其细胞毒性。毒性降低的原因可能是牛血清白蛋白（BSA）阻断细胞蛋白质吸附。在这里，我们的研究从蛋白质吸附的角度探讨了毒性降低的机制。不同的 BSA 负载量导致 SWCNT 的表面覆盖率不同，这与细胞毒性水平呈正相关。此外，还测试了 BSA 涂层的单壁碳纳米管的表面形态变化、细胞摄取和细胞蛋白质的吸附。BSA 可能会被胞质蛋白竞争离开 SWCNT 表面，因此需要更高的 BSA 负载量才能为细胞提供更好的保护。细胞摄取也随着 BSA 负载量的增加而减少。此外，BSA 涂层改变了单壁碳纳米管的表面性质，从而改变了单壁碳纳米管吸附的蛋白质类型。我们的结果支持，BSA 的吸附减少了单壁碳纳米管的细胞摄取以及单壁碳纳米管上细胞蛋白质的吸附，这两者都有助于观察到 BSA 涂覆的单壁碳纳米管的细胞毒性低得多。