In this paper, a convenient reverse‐phase microemulsion method for the synthesis of SiO₂ nanoparticles (NPs) by simply introducing the chitosan and fluorescent dye of lucigenin during the formation reaction of SiO₂ NPs was proposed. Addition of chitosan can make the SiO₂ NPs porous, and increases lucigenin molecule incorporation into chitosan/SiO₂ NPs nanopores based on electrostatic interaction and supermolecular forces. Therefore, fluorescence quantum yield of the lucigenin/chitosan/SiO₂ composite nanoparticles was increased by introduction of chitosan and compared with lucigenin/SiO₂ NPs without chitosan. Because the number of negative charges carried when using single‐stranded DNA (ssDNA) was different from that of double‐stranded DNA (dsDNA), the numbers of lucigenin/chitosan/SiO₂ composite nanoparticles with positive charge adsorbed using ssDNA or dsDNA were different. Consequently, fluorescence intensity caused using ssDNA or dsDNA/miRNA was clearly discriminative. With increase in target DNA/miRNA concentration, the difference in fluorescence intensity also increased, resulting in a good linear relationship between fluorescence intensity sensitizing value and target miRNA concentrations. Therefore, a new fluorescence analysis method for direct detection of let‐7a in human gastric cancer cell samples without enzyme, label free and no immobilization was established using lucigenin/chitosan/SiO₂ composite nanoparticles as a DNA hybrid indicator. The proposed method had high sensitivity and selectivity, low cost and the detection limit was 10 fM (S/N = 3).

中文翻译：

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基于光泽精/壳聚糖/ SiO2复合纳米颗粒的高灵敏度荧光传感器，用于使用磁分离进行microRNA检测。

在本文中，为二氧化硅的合成方便反相微乳液方法₂纳米颗粒（NP）的SiO的形成反应过程中简单地引入壳聚糖和光泽精的荧光染料₂提出的NP。壳聚糖的添加可以使SiO ₂ NPs具有多孔性，并基于静电相互作用和超分子力增加光黄蛋白分子掺入壳聚糖/ SiO ₂ NPs纳米孔中。因此，通过引入壳聚糖，与光泽精/ SiO ₂相比，提高了光泽精/壳聚糖/ SiO ₂复合纳米粒子的荧光量子产率。不含壳聚糖的NP。由于使用单链DNA（ssDNA）时所携带的负电荷数量与双链DNA（dsDNA）中所携带的负电荷数量不同，因此光泽黄素/壳聚糖/ SiO _2的数量用ssDNA或dsDNA吸附的带正电荷的复合纳米颗粒有所不同。因此，使用ssDNA或dsDNA / miRNA引起的荧光强度显然是有区别的。随着目标DNA / miRNA浓度的增加，荧光强度的差异也增加，导致荧光强度敏化值与目标miRNA浓度之间具有良好的线性关系。因此，建立了一种新的荧光分析方法，该方法可以直接使用荧光素/壳聚糖/ SiO ₂复合纳米颗粒作为DNA杂交指示剂，直接检测人胃癌细胞样品中let-7a的无酶，无标记且无固定化。该方法灵敏度高，选择性好，成本低，检测限为10 fM（S / N = 3）。