ZIF-8 SQDs电化学发光传感器超灵敏检测miRNA-141研究

Construction of ZIF-8/SQDs-based electrochemiluminescence sensing platform for ultrasensitive detection of miRNA-141

MiRNA-141被认为是临床早期癌症诊断的潜在生物标志物,因此,探索合适的方法对miRNA-141进行超灵敏检测具有重要意义.电化学发光(ECL)是由高能电子转移反应后产生的激发态物质回到基态时放出光子的过程,凭借其超高的灵敏度、低背景噪声以及出色的可控性等优点逐渐在生物分析定量、环境监测及食品安全检测等领域获得了广泛的关注.而发光体在ECL技术中起着电光转换器的重要作用,在各种具有ECL活性的材料中,硫量子点(SQDs)因其优异的水分散性、良好的生物相容性及突出的稳定性等优势成为极具潜力的ECL候选材料.本研究采用硫粉为原料,在纯氧气氛下通过自上而下的方法合成了尺寸均一、呈明亮蓝色荧光的SQDs.进一步以金属有机框架ZIF-8为基质对SQDs进行封装,实现SQDs的富集及稳定性提升.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、荧光光谱(FL)等方法对其结构和形貌进行表征.以该复合材料作为发光体,利用二茂铁(Fc)对ZIF-8/SQDs的猝灭效应,结合催化发夹自组装(CHA)信号放大策略及金纳米棒(Au NRs)作为共反应促进剂的信号增强作用,实现目标物miRNA-141高灵敏分析检测,检测限低至0.86 fmol/L(S/N=3),有望用于疾病早期诊断miRNA-141表达水平的检测.

MiRNA-141 are considered as a potential biomarker for clinical cancer diagnosis in the early stage, hence, it is of paramount significance to explore suitable means capable of ultrasensitive detection of miRNA-141. Electrochemiluminescence(ECL) is a process in which photons are generated by excited substances electrogenerated after high-energy electron transfer reactions and has acquired considerable attention in biological analysis, environmental monitoring, food safety field dues to its remarkably high sensitivity, low background and facile controllability. Meanwhile, ECL emitter plays a crucial role as an electronic-to-optical transducer. Among various ECL emitting materials, sulfur quantum dots(SQDs) offers a decent candidate as an ECL emitter due to its excellent dispersibility in water, favourable biocompatibility and prominent stability. Herein, under pure oxygen atmosphere, SQDs with uniform size and bright blue fluorescence were synthesized using sulfur powder by a top-down method. Further encapsulated by metal-organic frameworks ZIF-8, which largely enriched the luminophore loading capacity and improved its stability. The structure and morphology of ZIF-8/SQDs were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), and fluorescence spectroscopy(FL). Considered SQDs as the emitter, we utilized quenching effect of ferrocene on SQDs, and combined with the signal amplification strategy of catalytic hairpin self-assembly(CHA) and the signal enhancement effect of Au NRs as coreaction promoters, which achieved high sensitivity analysis and detection of target miRNA-141 with ultra-low detection limit of 0.86 fmol/L(S/N=3), indicating its promising potential to detect miRNA-141 expression level in early diagnosis of diseases.