水凝胶纳米纤维复合基底捕获循环肿瘤细胞的研究

Capture of Circulating Tumor Cells by Hydrogel-Nanofiber Substrate

循环肿瘤细胞(CTCs)检测被认为是一种极具发展前景的癌症液体活检技术。血液中CTCs数量非常稀少,因此,从血液中高效捕获高纯度、高活性的CTCs极具挑战。为提高CTCs捕获纯度,本研究通过自由基聚合反应在玻璃片表面修饰厚度约2.3μm的聚羧酸甜菜碱甲基丙烯酸甲酯(PCBMA)水凝胶,具有抗粘附作用,并提供一种类似细胞外基质的柔软界面。在水凝胶表面修饰抗上皮粘附分子(EpCAM)抗体后,对靶细胞的捕获效率仅约20%。为提高捕获效率,通过静电纺丝技术在水凝胶表面覆盖一层直径约200 nm的壳聚糖纳米纤维,使捕获基底具有纳米结构,最后引入EpCAM抗体作为亲和捕获分子用于特异性捕获EpCAM高表达的CTCs。实验结果表明,此水凝胶纳米纤维复合基底对靶细胞捕获效率可达85%,比平面水凝胶基底的捕获效率提高了4倍多;对阴性细胞的粘附率仅0.5%,并且97%的捕获细胞保持活性。对模拟病人样本中少量靶细胞的捕获效率可达79.9%。本研究所发展的捕获基底通过亲和捕获分子、抗粘附水凝胶和纳米纤维结构的协同作用实现了对CTCs的高效率捕获。

The method for detection of circulating tumor cells (CTCs) is considered as a promising cancer liquid biopsy technique. However, due to the rarity and heterogeneity, it is still a challenging task to capture CTCs with high purity and viability from blood for the following enumeration and molecular analysis. Herein, we fabricated a hydrogel-chitosan nanofiber substrate to effectively capture the target cancer cells, assisted by the poly(carboxybetaine methacrylate) (PCBMA) hydrogel and the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody. The PCBMA hydrogel layer was fabricated by free radical polymerization to provide an antifouling surface, which could help to reduce the non-specific capture of blood cells to improve the capture purity of CTCs. Then, chitosan nanofibers were introduced onto the hydrogel layer to provide a nanostructured surface to improve the capture efficiency. Finally, the capture yield of artificial blood samples on the anti-EpCAM modified hydrogel-nanofiber substrate was up to 79.9%, revealing the potential application of the hydrogel-nanofiber substrate on efficient and sensitive capture of rare circulating tumor cells.