The overexpression of microRNA-222 (miRNA-222) is closely related to many human diseases, so the development of biosensors to detect this biomarker will contribute to the diagnosis of related diseases. Here, a simple, sensitive and specific fluorescence assay for the detection of miRNA-222 was developed using red-emitting upconversion nanoparticle (UCNP) as the donor and a DNA hairpin with black hole quencher-2 (BHQ-2) as the acceptor. Li⁺ and Tm³⁺-doped UCNP with a strong emission peak at 654 nm was obtained by changing the doped ion ratio and constructing core-shell structures. Under optimal conditions, the linear range for detecting miRNA-222 is 0.5–2.5 nM and the limit of detection is as low as 0.077 nM without any complicated amplification strategy. Finally, the proposed assay was applied for the detection of miRNA-222 in serum samples. The results obtained were similar to those of the standard method, and the spiked recoveries were in the range of 97.62%–102.14 %, suggesting that the proposed method has practical value in a complex biological sample matrix.

中文翻译：

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通过 Li+ 和 Tm3+ 共掺杂和活性核壳构建增强上转换纳米颗粒的红色发射，用于灵敏检测 miRNA


microRNA-222 （miRNA-222） 的过表达与许多人类疾病密切相关，因此开发检测这种生物标志物的生物传感器将有助于相关疾病的诊断。在这里，以红色发射上转换纳米颗粒 （UCNP） 为供体，以黑洞淬灭基 2 （BHQ-2） 为受体的 DNA 发夹，开发了一种简单、灵敏和特异性的 miRNA-222 检测荧光测定法。通过改变掺杂离子比例并构建核壳结构，获得了在 654 nm 处具有强发射峰的 Li⁺ 和 Tm³⁺ 掺杂 UCNP。在最佳条件下，检测 miRNA-222 的线性范围为 0.5–2.5 nM，检测限低至 0.077 nM，无需任何复杂的扩增策略。最后，将所提出的检测方法应用于血清样品中 miRNA-222 的检测。所得结果与标准方法相似，加标回收率在 97.62%–102.14 % 范围内，表明所提方法在复杂的生物样品基质中具有实用价值。