Nanodiamonds (NDs) have been recognized as emerging carbon-based delivery vehicles due to their biocompatibility. NDs were reported to be nontoxic and suited for biomedical applications in the complete cell culture medium. However, in this study, the cytotoxicity of NDs in serum-free medium was studied and indicated that serum proteins in cell culture medium played significant effect on the toxicity of NDs. Therefore, the interaction mechanism between NDs and a serum protein (human serum albumin, HSA) was first investigated by fluorescence quenching technique and circular dichroism (CD) spectrometry. The results suggest that HSA strongly bonds on the NDs surface to form “protein corona,” which not only prevents the aggregation of NDs and improves its stability but also inhibits the cytotoxicity of NDs. In serum-free medium, NDs exhibited obvious toxicity toward the human lung epithelial cell line (BEAS-2B) and showed concentration-dependent cytotoxicity. In the presence of bovine serum albumin (BSA), which shares structural homology and similar properties with HSA, toxicity of NDs was apparently inhibited. Therefore, the interaction between serum protein and NDs should be considered in the understanding of the biological effects of NDs exposure in biomedical applications.

中文翻译：

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研究纳米金刚石与人血清白蛋白的相互作用和诱导的细胞毒性

纳米金刚石（NDs）由于其生物相容性而被公认为新兴的碳基输送工具。据报道，NDs是无毒的，适合在完整细胞培养基中用于生物医学应用。然而，在本研究中，研究了无血清培养基中NDs的细胞毒性，并表明细胞培养基中的血清蛋白对NDs的毒性具有显着影响。因此，首先通过荧光猝灭技术和圆二色谱（CD）光谱法研究了NDs与血清蛋白（人血清白蛋白，HSA）之间的相互作用机理。结果表明，HSA在NDs表面牢固结合形成“蛋白电晕”，不仅可防止NDs聚集并提高其稳定性，而且还可抑制NDs的细胞毒性。在无血清培养基中，NDs对人肺上皮细胞系（BEAS-2B）表现出明显的毒性，并表现出浓度依赖性的细胞毒性。牛血清白蛋白（BSA）与HSA具有结构同源性和相似的特性，因此其NDs的毒性明显受到抑制。因此，在了解生物医学应用中NDs暴露的生物学效应时，应考虑血清蛋白与NDs之间的相互作用。