由于急性胰腺炎 (AP) 发病率高、预后差、易转化为高死亡率的胰腺癌 (PC)，早期诊断和预防已成为重要的研究重点。本研究提出了一种带有空间限制的磁单滴微萃取 (SDME) 系统，以增强集聚诱导发光 (AIE) 效应来同时检测与 AP 相关的 miRNA-155 和与 PC 相关的 miRNA-196a。目标 miRNA 通过发夹探针进行选择性识别并触发 DNA 扩增反应，然后在磁珠表面构建了带有两个独立探针的 G-四链体/TAIN 和 Cy5 的 DNA 单链。SDME 过程通过磁提取在 10 秒内快速形成含荧光探针的滴液，在单滴系统的空间限制下，G-四链体/TAIN 得到了富集，发出的荧光信号得到了高度增强 (AIE 效应)，并通过荧光分光光度法直接检测。该方法实现了对 miRNA-196a 的低检测限为 2.1 aM 和对 miRNA-155 的低检测限为 8.1 aM，线性范围广，miRNA-196a 的线性范围为 10 aM 到 10 nM，miRNA-155 的线性范围为 25 aM 到 10 nM。该新方法应用于人血清样品中 miRNA 的荧光检测，获得了 95.6％ 到 104.8％ 的高相对回收率。

Due to high incidence, poor prognosis, and easy transformation into pancreatic cancer (PC) with high mortality, early diagnosis and prevention of acute pancreatitis (AP) have become significant research focuses. In this work, we proposed a magnetic single-drop microextraction (SDME) system with spatial confinement to enhance the aggregation-induced emission (AIE) effect for simultaneous fluorescence detection of miRNA-155 (associated with AP) and miRNA-196a (associated with PC). The target miRNAs were selectively recognized by the hairpin probe and triggered the DNA amplification reaction; then, the DNA strands with two independent probes of G-quadruplex/TAIN and Cy5 were constructed on the surfaces of the magnetic beads. The SDME process, in which a drop containing the fluorescence probes was formed at the tip of the magnetic microextraction rod rapidly within 10 s, was performed by magnetic extraction. In this way, G-quadruplex/TAIN was enriched owing to the spatial confinement of the single-drop system, and the fluorescence signal given off (by G-quadruplex/TAIN) was highly enhanced (AIE effect). This was detected directly by fluorescence spectrophotometry. The approach achieved low limits of detection of 2.1 aM for miRNA-196a and 8.1 aM for miRNA-155 and wide linear ranges from 10 aM to 10 nM for miRNA-196a and from 25 aM to 10 nM for miRNA-155. This novel method was applied to the fluorescence detection of miRNAs in human serum samples. High relative recoveries from 95.6% to 104.8% were obtained.