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Convertible DNA ends-based silver nanoprobes for colorimetric detection human telomerase activity
Talanta ( IF 6.1 ) Pub Date : 2017-09-19 , DOI: 10.1016/j.talanta.2017.09.057
Wenjing Chen , Lei Wang , Rong He , Xiaowen Xu , Wei Jiang

Human telomerase is an endogenous ribonucleoprotein that is over-expressed in most types of malignant cancer cells. Sensitive and specific detection of telomerase activity is crucial for better understanding its role in cancer cells and further exploring its function in cancer diagnosis. Here, we develop convertible DNA ends-based silver nanoprobes for sensitive and specific colorimetric detection telomerase activity. Silver nanoprobes are constructed by modifying telomerase binding substrates (TS) that are pre-hybridized with complementary sequences onto silver nanoparticles (AgNPs), via the coordination between consecutive cytosines in TS strand and AgNPs. This forms blunt-end terminated, double-stranded DNA on the surface of AgNPs. Under the action of telomerase, TS on the silver nanoprobes are elongated with telomeric repeats, converting DNA stiff blunt ends to flexible single-stranded dangling ends. The dangling ends enhance the stability of nanoprobes and relieve their salt-induced aggregation, and the solution shows a yellow color. When telomerase is inactive, the blunt end-terminated nanoprobes cannot resist salt-induced aggregation, resulting in a gray color of solution. Based on telomerase-regulated DNA “blunt-dangling” ends conversion-induced AgNPs' dispersity and color change, colorimetric detection of the endogenous telomerase with AgNPs is realized. The detection limit is equivalent to 1 cell/μL of telomerase activity, and extracts from cancer cells and normal cells are visually distinguished through color difference. The proposed strategy will offer a new approach for reliable, convenient quantification of telomerase activity in biochemical research and clinical diagnosis.



中文翻译:

可比DNA末端的银纳米探针,用于比色检测人类端粒酶活性

人端粒酶是一种内源性核糖核蛋白,在大多数类型的恶性癌细胞中过表达。敏感,特异地检测端粒酶活性对于更好地了解其在癌细胞中的作用以及进一步探索其在癌症诊断中的功能至关重要。在这里,我们开发了可转换的基于DNA末端的银纳米探针,用于灵敏和特异的比色检测端粒酶活性。银纳米探针是通过修饰端粒酶结合底物(TS)来构建的,该底物通过互补链中连续的胞嘧啶和AgNPs之间的配位,与互补序列预先杂交到银纳米颗粒(AgNPs)上。这会在AgNP的表面形成末端平末端的双链DNA。在端粒酶的作用下,银纳米探针上的TS被端粒重复序列延长,将DNA刚性的钝端转化为柔性的单链悬挂端。悬空的末端增强了纳米探针的稳定性并缓解了其盐诱导的聚集,溶液呈黄色。当端粒酶失活时,末端钝的纳米探针不能抵抗盐诱导的聚集,从而导致溶液呈灰色。基于端粒酶调控的DNA“钝端”末端转化诱导的AgNPs的分散性和颜色变化,实现了用AgNPs比色检测内源性端粒酶。检出限相当于1个细胞/μL的端粒酶活性,并且通过色差在视觉上区分癌细胞和正常细胞的提取物。拟议的策略将提供一种新的方法来实现可靠,

更新日期:2017-09-19
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