Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States.
Texas A&M University, Irma Lerma Rangel College of Pharmacy, College Station, Texas, United States.
J Biomed Opt. 2018 Jan;23(1):1-11. doi: 10.1117/1.JBO.23.1.017002.
DNA-functionalized nanoparticles, when paired with surface-enhanced Raman spectroscopy (SERS), can rapidly detect microRNA. However, widespread use of this approach is hindered by drawbacks associated with large and expensive benchtop Raman microscopes. MicroRNA-17 (miRNA-17) has emerged as a potential epigenetic indicator of preeclampsia, a condition that occurs during pregnancy. Biomarker detection using an SERS point-of-care device could enable prompt diagnosis and prevention as early as the first trimester. Recently, strides have been made in developing portable Raman systems for field applications. An SERS assay for miRNA-17 was assessed and translated from traditional benchtop Raman microscopes to a handheld system. Three different photoactive molecules were compared as potential Raman reporter molecules: a chromophore, malachite green isothiocyanate (MGITC), a fluorophore, tetramethylrhodamine isothiocyanate, and a polarizable small molecule 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB). For the benchtop Raman microscope, the DTNB-labeled assay yielded the greatest sensitivity under 532-nm laser excitation, but the MGITC-labeled assay prevailed at 785 nm. Conversely, DTNB was preferable for the miniaturized 785-nm Raman system. This comparison showed significant SERS enhancement variation in response to 1-nM miRNA-17, implying that the sensitivity of the assay may be more heavily dependent on the excitation wavelength, instrumentation, and Raman reporter chosen than on the plasmonic coupling from DNA/miRNA-mediated nanoparticle assemblies.
DNA 功能化纳米粒子与表面增强拉曼光谱（SERS）结合使用，可以快速检测 microRNA。然而，由于与大型昂贵的台式拉曼显微镜相关的缺点，这种方法的广泛应用受到阻碍。microRNA-17（miRNA-17）已成为先兆子痫的潜在表观遗传标志物，先兆子痫是一种在怀孕期间发生的疾病。使用 SERS 即时护理设备进行生物标志物检测可以实现早期诊断和预防，最早可在妊娠第一 trimester 进行。最近，在开发用于现场应用的便携式拉曼系统方面取得了进展。对 miRNA-17 的 SERS 测定进行了评估，并从传统的台式拉曼显微镜转化为手持式系统。比较了三种不同的光活性分子作为潜在的拉曼报告分子：一种生色团，孔雀石绿异硫氰酸酯（MGITC），一种荧光团，四甲基罗丹明异硫氰酸酯，以及一种可极化小分子 5,5-二硫代双（2-硝基苯甲酸）（DTNB）。对于台式拉曼显微镜，在 532nm 激光激发下，DTNB 标记的测定产生了最大的灵敏度，但在 785nm 下，MGITC 标记的测定占主导地位。相反，DTNB 更适合小型化的 785nm 拉曼系统。这种比较表明，1nM miRNA-17 会引起显著的 SERS 增强变化，这意味着测定的灵敏度可能更依赖于激发波长、仪器和选择的拉曼报告分子，而不是 DNA/miRNA 介导的纳米粒子组装的等离子体耦合。
