Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
J Mater Chem B. 2019 Apr 28;7(16):2643-2647. doi: 10.1039/c8tb02894j. Epub 2019 Mar 20.
In this work, a novel ratiometric SERS biosensor with only one Raman probe was fabricated in combination with the DNA hydrogel-captured glucose oxidase (GOx) amplification method to realize an accurate and sensitive assay for microRNA (miRNA) 122, which could overcome the complex operational process and chemical waste issues of the traditional ratiometric approach with two different signal probes. Here, 3-mercaptophenylboronic acid (3-MPBA) as a standard reference with a unique Raman peak at 996 cm was first connected to silica@Au nanoflower (Si@AuNF) SERS substrates. When the DNA hydrogel containing GOx was opened by the released DNA (R) from the target miRNA-induced cycle amplification process, GOx could be released from the DNA hydrogel. Therefore, GOx could catalyze the oxidation of glucose to produce HO on Si@AuNFs. Subsequently, the acquired HO could further react with 3-MPBA to produce 3-hydroxythiophenol (3-HTP) with a new Raman peak at 883 cm. During this time, the intensity of the peak at 996 cm almost remained the same, which could act as a reference standard. The intensity ratio of 883 cm to 996 cm increased with the increase in the concentration of target miRNA 122, thus achieving quantitative detection of miRNA 122. As a consequence, our SERS biosensor could sensitively detect miRNA 122 from 10 aM to 100 pM, and the detection limit was 7.75 aM. Our strategy adopts a novel ratiometric method with one Raman probe to detect miRNA, opening a new avenue for the detection of trace amounts of biological samples with high sensitivity and accuracy.
在这项工作中，结合 DNA 水凝胶捕获葡萄糖氧化酶 (GOx) 扩增方法，制备了一种新型的比率型 SERS 生物传感器，仅使用一种拉曼探针，以实现对 microRNA (miRNA) 122 的准确灵敏检测，从而克服了传统比率法需要两种不同信号探针的复杂操作过程和化学废物问题。在这里，首先将 3-巯基苯硼酸 (3-MPBA) 作为具有独特拉曼峰在 996cm 的标准参考物连接到硅@金纳米花 (Si@AuNF) SERS 基底上。当含有 GOx 的 DNA 水凝胶被目标 miRNA 诱导循环扩增过程中释放的 DNA (R) 打开时，GOx 可以从 DNA 水凝胶中释放出来。因此，GOx 可以催化葡萄糖的氧化，在 Si@AuNFs 上产生 HO。随后，获得的 HO 可以进一步与 3-MPBA 反应，生成具有新拉曼峰在 883cm 的 3-羟基噻吩 (3-HTP)。在此期间，996cm 处的峰强度几乎保持不变，可以作为参考标准。883cm 处的峰强度与目标 miRNA 122 的浓度增加成正比，从而实现了 miRNA 122 的定量检测。因此，我们的 SERS 生物传感器可以从 10 aM 到 100 pM 灵敏地检测 miRNA 122，检测限为 7.75 aM。我们的策略采用了一种新型的比率型方法，仅使用一种拉曼探针来检测 miRNA，为具有高灵敏度和准确性的痕量生物样本检测开辟了新途径。
