The controllable growth of metal nanoparticles on nanomaterials is becoming a useful strategy for developing nanocomposites with designated performance. Here, a DNA-controlled strategy for growth of Pt nanoparticles on graphene oxide (GO-PtNPs) to regulate the nanozyme activity and a triplex-hybridization chain reaction (tHCR) for triggering the assembly of DNA probes to amplify the target-induced nanozyme catalytic signal were designed. The tHCR with one linear and two hairpin probes could be specially triggered by a tHCR trigger to form a long double-stranded DNA structure in the presence of target nucleic acid, which hindered the adsorption of these probes on a GO surface, and thus accelerated the growth of PtNPs. The formed GO-PtNPs showed strong catalytic activity toward the oxidation of 3,3,5,5-tetramethylbenzidine, thereby producing an amplified "turn-on" detection signal. The proposed method showed very high sensitivity with the detection limits down to 14.6 pM for mutant KRAS DNA and 21.7 pM for let-7a microRNA. This method was validated with better analytical performance than a general HCR system and could be effectively used for the identification of single-nucleotide polymorphisms, thus providing a novel approach for simple and sensitive detection of nucleic acids.

中文翻译：

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通过三重杂交链反应比色检测核酸，并在氧化石墨烯上控制铂纳米颗粒的DNA控制生长。

金属纳米颗粒在纳米材料上的可控生长正成为开发具有指定性能的纳米复合材料的有用策略。在此，提出了一种用于控制Pt纳米颗粒在氧化石墨烯（GO-PtNPs）上生长以调节纳米酶活性的DNA控制策略，以及用于触发DNA探针组装以扩增靶标诱导的纳米酶催化的三链杂交链反应（tHCR）信号被设计。带有一个线性和两个发夹探针的tHCR可以由tHCR触发器专门触发，从而在靶核酸存在下形成长双链DNA结构，这阻碍了这些探针在GO表面的吸附，从而加速了PtNPs的生长。形成的GO-PtNP对3,3,5,5-四甲基联苯胺的氧化表现出较强的催化活性，从而产生放大的“接通”检测信号。所提出的方法显示出非常高的灵敏度，突变KRAS DNA的检测限低至14.6 pM，let-7a microRNA的检测限低至21.7 pM。经过验证，该方法具有比一般HCR系统更好的分析性能，可有效地用于鉴定单核苷酸多态性，从而为简单，灵敏地检测核酸提供了一种新颖的方法。