在这项研究中,设计了一种新型的基于脂质体的集成微流控平台,结合智能手机,用于快速比色检测真实样品中的microRNA-21(miRNA-21).流动的表面官能化脂质体首先被微流体芯片中的核酸官能化Au纳米颗粒捕获。在miRNA-21的存在下,在Au纳米颗粒表面修饰的DNA链与靶标杂交形成双链产物,并被双链体特异性核酸酶(DSN)酶切割,导致脂质体重新释放。然后,随着比色模块中的脂质体被裂解,“细胞”内容物被释放,一步一步的“葡萄糖-葡萄糖氧化酶-3,3”,触发了G-四链体/血红素催化的5,5'-四甲基联苯胺(TMB)比色反应过程。记录灰度值并通过智能手机相机识别用于miRNA-21分析。本策略的优点包括基于智能手机的比色测定的便携性,脂质体对反应物的封装和运输以及微流控芯片的低溶剂使用量。在最优条件下,该测定表现出从1pM到1nM的宽线性范围(r2=0.9981),miRNA-21的检测限低至0.27pM。此外,该策略的高特异性使其成功应用于2型糖尿病患者真实血清样本中miRNA-21的快速分析.
In this study, a novel integrated
liposome-based microfluidic platform combined with a smartphone was designed for the rapid colorimetric detection of microRNA-21 (miRNA-21) in real samples. The flowing surface-functionalized liposomes were first captured by nucleic acid-functionalized Au nanoparticles in the microfluidic chip. In the presence of miRNA-21, the DNA strand modified on the surface of Au nanoparticles hybridized with the target to form double-stranded products and was cleaved by duplex-specific nuclease (DSN) enzyme, causing the liposomes to be re-released. Then, as the liposomes in the colorimetric module were lysed and the \"cellular\" contents were released, a step-by-step \"glucose-glucose oxidase-3,3\',5,5\'-tetramethylbenzidine (TMB)\" colorimetric reaction process catalyzed by the G-quadruplex/hemin was triggered. The grayscale values were recorded and recognized by the smartphone camera for miRNA-21 analysis. The advantages of the present strategy included the portability of smartphone-based colorimetric assay, the encapsulation and transport of reactants by liposomes and the low solvent usage of microfluidic chip. Under optimal conditions, this assay exhibited a wide linear range from 1 pM to 1 nM (r2 = 0.9981), and the limit of detection of miRNA-21 was as low as 0.27 pM. Moreover, the high specificity of this strategy allowed its successful application to the rapid analysis of miRNA-21 in real blood serum samples of people with type 2 diabetes.