文献：

Polyethylene glycol-modified cobalt sulfide nanosheets for high-performance photothermal conversion and photoacoustic/magnetic resonance imaging

文献链接：

作者：

Zhenglin Li, Zhuo Li, Lei Chen, Ying Hu, Shaoshan Hu, Zhaohua Miao, Ye Sun,Flemming Besenbacher,and Miao Yu

相关产品：

DA-PEG（多巴胺-聚乙二醇）

原文摘要：

Theranostic nanoagents that integrate the diagnoses and therapies within a single nanomaterial are compelling in their use for highly precise and efficient antitumor treatments. Herein, polyethylene glycol (PEG)-modified cobalt sulfide nanosheets (CoS-PEG NSs) are synthesized and unitized as a powerful theranostic nanoagent for efficient photothermal conversion and multimodal imaging for the first time. We demonstrate that the obtained CoS-PEG NSs show excellent compatibility and stability in water and various physiological solutions, and can be effectively internalized by cells, but exhibit a low cytotoxicity. The CoS-PEG NSs exhibit an efficient photothermal conversion capacity, benefited from the strong near-infrared (NIR) absorption, high photothermal conversion efficiency (~33.0%), and excellent photothermal stability. Importantly, the highly effective photothermal killing effect on cancer cells after exposure to CoS-PEG NSs plus laser irradiation has been confirmed by both the standard Cell Counting Kit-8 and live-dead cell staining assays,revealing a concentration-dependent photothermal therapeutic effect. Moreover,utilizing the strong NIR absorbance together with the T2-MR contrast ability of the CoS-PEG NSs, a high-contrast triple-modal imaging, i.e., photoacoustic (PA), infrared thermal (IRT), and magnetic resonance (MR) imaging, can be achieved, suggesting a great potential for multimodal imaging to provide comprehensive cancer diagnosis. Our work introduces the first bioapplication of the CoS-PEG nanomaterial as a potential theranostic nanoplatform and may promote further rational design of CoS-based nanostructures for precise/efficient cancer diagnosis and therapy.

DA - PEG 是指多巴胺（Dopamine，DA）修饰的聚乙二醇（Polyethylene glycol，PEG）。聚乙二醇是一种合成的聚合物，它是由环氧乙烷聚合而成，其中表示环氧乙烷的聚合度，其分子量可以通过控制聚合反应条件来调节。PEG 具有良好的水溶性、生物相容性和低poison性等特点。多巴胺是一种神经递质，其化学结构中含有氨基和酚羟基。当多巴胺与 PEG 连接后，形成的 DA - PEG 结合了多巴胺的活性基团和 PEG 的优良性质。通常是通过多巴胺的氨基或酚羟基与 PEG 分子链上的活性基团（如羧基、羟基等）发生化学反应（如酰胺化反应、酯化反应等）来实现连接。基于DA - PEG的性质，该文献合成PEG改性的硫化钴纳米片CoS-PEG NSs的流程如下：

图：合成及作用机制

将Co（NO3）2·6H2O、TAA和PVP溶解在去离子水中。在磁性搅拌下加入氢氧化钠水溶液后，将混合物溶液加热并保持一段时间。在反应过程中，溶液的颜色由海蓝宝石变为黑色，表明了CoS NSs的形成。冷却至室温后，离心收集沉淀，然后用去离子水彻底洗涤，用无水乙醇彻底洗涤。对于PEG涂层，将制备的CoS NSs重新分散在DA-PEG水溶液中，并搅拌过夜。通过离心去离子水反复洗涤，去除多余的DA-PEG分子，然后冷冻以进一步使用。

图：电镜图像

结论：

该文献成功制备出基于DA-PEG 合成了经聚乙二醇（PEG）改性硫化钴纳米片（CoS-PEG NSs）。结果表明，所获得的CoS-PEG NSs在水和各种生理溶液中具有良好的相容性和稳定性，可被细胞有效内化，但具有较低的细胞poison性。CoS-PEG NSs具有光热转换能力，具有较强的近红外（NIR）吸收能力、较高的光热转换效率和良好的光热稳定性。