文献：In Vivo Coinstantaneous Identification of Hepatocellular Carcinoma Circulating Tumor Cells by Dual-Targeting Magnetic-Fluorescent Nanobeads

文献链接：

https://pubmed.ncbi.nlm.nih.gov/33264027/

作者：Wenxi Xia,Haidong Li,Yueqing Li,Miao Li,Jiangli Fan,Wen Sun,Na Li, Ruojie Li,⊥ Kun Shao,and Xiaojun Peng

相关产品：TCO-PEG4-NHS Ester

原文摘要：

Circulating tumor cells (CTCs) have been considered as a potential biomarker for evaluation of cancer metastasis and prognosis, especially in hepatocellular carcinoma (HCC). However, the isolation and detection of rare CTCs in HCC patients face enormous challenges due to omittance and nonspecific binding. We previously designed a small molecular NIR fluoresent agent, named MLP, which had high affinity with a tumor cell-overexpressed enzyme, aminopeptidase N (APN). Based on that, in this work we introduced a novel strategy via coassembling the antiepithelial cell adhesion molecule (EpCAM) antibody and MLPinto theFe3O4 magnetic nanobeads (MB-MLP-EpCAM) to isolate and identify HCC-CTCs coinstantaneously. MB-MLP-EpCAM significantly improved the CTC-capture efficiency (>85%) without sacrificing cell viability (>90%). Most importantly, the advantages of precise dual-targetability, high resolution of fluorescence imaging, and prominent selectivity make our nanoplatform have great potential to achieve in vivo real-time identification and monitoring of CTCs clinically.   

TCO - PEG4 - NHS Ester 是一种有机化合物。TCO 代表反式-环辛烯（trans - Cyclooctene），它是一种具有特殊反应活性的烯烃结构。PEG4 是聚乙二醇（Polyethylene glycol）链段，其中数字 4 表示乙二醇单元的数量，其作用是增加化合物的水溶性和生物相容性等。NHS Ester 是 N - 羟基琥珀酰亚胺酯（N - Hydroxysuccinimide ester），它是一种活性酯，能够与含有氨基的化合物发生反应。该化合物的结构中，TCO 部分提供了与四嗪（Tetrazine）进行生物正交反应（Bio - orthogonal reaction）的位点，这是一种在生物体内或复杂化学环境中能够特异性发生、而不干扰其他生物过程的化学反应。PEG4 链段连接 TCO 和 NHS Ester，NHS Ester 部分则可以与蛋白质、肽、氨基修饰的寡核苷酸等生物分子表面的伯氨基（-NH₂）反应，形成稳定的酰胺键，从而将 TCO - PEG4 部分引入到目标生物分子中。基于TCO - PEG4 - NHS Ester的性质，MB-MLP-EpCAM合成如下：

图：TCO-PEG4-NHS ester结构式

MB-MLP-EpCAM的合成：

将Fe3O4-COOH在DMSO中溶解，并在室温下超声。然后，将Fe3O4-COOH溶液加入EDC、DMAP、三乙胺、MLP-PEG和TZ-PEG中。让混合物在一定温度下反应。反应结束后，离心去除未反应的产物，用dd水保存。

结论：

该文献成功制备出基于TCO - PEG4 - NHS Ester合成的磁性纳米珠MB-MLP-EpCAM。磁性纳米珠（MB-MLP-EpCAM）可以同时识别和分离HCC-CTC。MB-MLP-EpCAM明显提高了CTC捕获效率，而不会降低细胞活力。