AbstractA fluorescent method is described for simultaneous recognition of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). It is based on the quenching of the fluorescence of fluorophore labeled DNA probes by gold nanoparticles (AuNPs). To demonstrate feasibility, two DNA probes labeled with spectrally different fluorophores were designed. The first DNA probe (P1) was modified with 6-carboxyfluorescein (FAM; with green fluorescence, peaking at 518 nm), while the second (P2) was modified with carboxy-X-rhodamine (ROX; with yellow fluorescence, 610 nm). The fluorescence signals of the labels are quenched if P1 or P2 are adsorbed on AuNPs. Upon addition of ssDNA and dsDNA, hybridization occurs between P1 and ssDNA to form a dsDNA. In contrast, P2 hybridizes with dsDNA such that a triplex DNA is formed. As a result, the dsDNA and the triplex DNA, respectively, are desorbed from the surface of the AuNPs so that quenching no longer can occur and strong fluorescence can be observed. Under the optimal conditions, ssDNA and dsDNA can be detected simultaneously via the green and yellow fluorescence, respectively. The detection limits can be as low as 330 pM. In particular, the method has excellent selectivity for the target DNAs over control DNAs. Graphical abstractA gold nanoparticle based fluorescent probe for simultaneous recognition of single-stranded DNA and double-stranded DNA is developed based on the fluorescence quenching of gold nanoparticles to different fluorophore labeled DNA probes.

中文翻译：

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一种用于同时识别单链 DNA 和双链 DNA 的基于金纳米颗粒的荧光探针

摘要描述了一种用于同时识别单链 DNA (ssDNA) 和双链 DNA (dsDNA) 的荧光方法。它基于荧光团标记的 DNA 探针的荧光被金纳米粒子 (AuNPs) 淬灭。为了证明可行性，设计了两种用光谱不同的荧光团标记的 DNA 探针。第一个 DNA 探针 (P1) 用 6-羧基荧光素 (FAM；绿色荧光，峰值在 518 nm) 修饰，而第二个 (P2) 用羧基-X-罗丹明 (ROX；黄色荧光，610 nm) 修饰. 如果 P1 或 P2 吸附在 AuNP 上，则标记的荧光信号会被淬灭。添加 ssDNA 和 dsDNA 后，P1 和 ssDNA 之间发生杂交，形成 dsDNA。相反，P2 与 dsDNA 杂交，从而形成三链 DNA。因此，dsDNA 和三链 DNA 分别从 AuNP 的表面解吸，从而不再发生猝灭，并且可以观察到强荧光。在最佳条件下，可以分别通过绿色和黄色荧光同时检测 ssDNA 和 dsDNA。检测限可低至 330 pM。特别是，该方法对目标 DNA 的选择性优于对照 DNA。图形摘要基于金纳米粒子对不同荧光团标记的 DNA 探针的荧光猝灭，开发了一种基于金纳米粒子的荧光探针，用于同时识别单链 DNA 和双链 DNA。ssDNA 和 dsDNA 可以分别通过绿色和黄色荧光同时检测。检测限可低至 330 pM。特别是，该方法对目标 DNA 的选择性优于对照 DNA。图形摘要基于金纳米粒子对不同荧光团标记的 DNA 探针的荧光猝灭，开发了一种基于金纳米粒子的荧光探针，用于同时识别单链 DNA 和双链 DNA。ssDNA 和 dsDNA 可以分别通过绿色和黄色荧光同时检测。检测限可低至 330 pM。特别是，该方法对目标 DNA 的选择性优于对照 DNA。图形摘要基于金纳米粒子对不同荧光团标记的 DNA 探针的荧光猝灭，开发了一种基于金纳米粒子的荧光探针，用于同时识别单链 DNA 和双链 DNA。