基于末端转移酶扩增的量子点电化学传感器在肿瘤细胞超灵敏检测中的应用效果

Application effect of a quantum dot-based electrochemical sensor amplified by terminal deoxynucleotidyl transferase in ultrasensitive detection of tumor cells

摘要

目的：构建一种基于末端转移酶（terminal deoxynucleotidyl transferase，TdT）扩增的量子点电化学传感器，实现对肿瘤细胞表面上皮细胞黏附分子（epithelial cell adhesion molecule，EpCAM）的超灵敏检测。方法：采用水热法两步合成了DNA功能化量子点（DNA-functionalized quantum dot，QD-DNA），利用末端转移酶构建延伸长聚合适配体，将两者杂交获得偶联探针，进一步构建电化学传感器；系统考察该传感器的重现性、抗干扰能力及特异性，并监测药物治疗过程中MCF-7细胞的表型变化。结果：成功制备了基于TdT扩增的量子点电化学传感器，其检测限低至80个细胞，展现出良好的检测灵敏度、特异性、准确性与抗干扰能力；该传感器可有效检测不同细胞表面EpCAM的表达水平，并动态监测药物治疗肿瘤细胞的表型变化。结论：基于TdT扩增的量子点电化学传感器可有效区分肿瘤细胞与正常细胞，且能动态监测药物治疗肿瘤细胞的表型变化，在肿瘤早期诊断与精准筛查中展现出良好的应用前景。

Abstract

Objective: To construct a quantum dot-based electrochemical sensor amplified by terminal deoxynucleotidyl transferase (TdT) for the ultrasensitive detection of epithelial cell adhesion molecule (EpCAM) on the surface of tumor cells. Methods: A two-step hydrothermal method was adopted to synthesize DNA-functionalized quantum dot (QD-DNA). TdT was used to construct extended long polymeric aptamers. The two components were hybridized to obtain conjugated probes, and an electrochemical sensor was further fabricated. The reproducibility, anti-interference capability and specificity of the sensor were systematically investigated; meanwhile, the phenotypic changes of MCF-7 cells during drug treatment were monitored. Results: The QD-based electrochemical sensor amplified by TdT was successfully fabricated, with a detection limit as low as 80 cells, showing favorable detection sensitivity, specificity, accuracy and anti-interference capability. The sensor could effectively detect the expression levels of EpCAM on different cell surfaces and dynamically monitor the phenotypic changes of tumor cells during drug treatment. Conclusion: The QD-based electrochemical sensor amplified by TdT can effectively distinguish tumor cells from normal cells and dynamically monitor the phenotypic changes of tumor cells during drug treatment, showing promising application potential in early tumor diagnosis and precise screening.

关键词

量子点 / 末端转移酶 / 扩增 / 电化学传感器 / 检测 / 肿瘤细胞 / 早期诊断 / 精准筛查

Key words

quantum dots / terminal deoxynucleotidyl transferase / amplification / electrochemical sensor / detection / tumor cells / early diagnosis / precise screening

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基金资助

国家自然科学基金资助项目(82574364)

广西科技基地和人才专项基金资助项目(桂科 AD23026133)

广西自然科学基金资助项目(2026GXNSFBA00640377)