银覆盖冠状硅柱阵列基底的制备、SERS特性分析及肿瘤标志物miRNA-106a的检测

Silver-covered Si Corona-pillar Array Substrate: Fabrication, SERS Characteristic Analysis and Detection of Tumor Marker miRNA-106a

以聚苯乙烯(PS)小球为模板,采用金属辅助刻蚀和湿法化学刻蚀技术,制备大面积冠状硅柱阵列,再原位生长银纳米粒子后得到银覆盖冠状硅柱阵列(Ag/Si CPA)基底。实验表明,制备的基底具有优良的表面增强拉曼散射(SERS)特性,电磁增强因子达到1.81×10~6。同时,将制备的罗丹明分子(R6G)标记的DNA发卡探针与基底链接,在与miRNA-106a互补杂交后进行SERS信号检测,获得相应的剂量-响应曲线。结果表明,基于(Ag/Si CPA)基底的SERS特性,开展miRNA-106a的检测,具有特异性好和灵敏度高的优势,检测范围为1 fmol·L^(-1)～100 pmol·L^(-1),检测极限为0.917 fmol·L^(-1)。此外,与实时荧光定量多聚核苷酸链式反应(RT-qPCR)方法相比,不仅检测结果一致,而且基于SERS光谱技术的检测方法具有更高的灵敏度。

Polystyrene(PS) spheres were used as a template, and the metal-assisted etching and wet chemical etching techniques were applied to prepare large-area Si corona-pillar arrays, silver nanoparticles were then grown in-situ to obtain silver-covered Si corona-pillar array(Ag/Si CPA) substrate. The experimental results show that the prepared substrate has excellent surface enhanced Raman scattering(SERS) characteristics, and its electromagnetic enhancement factor is up to 1.81×106. Meanwhile, the rhodamine molecule(R6 G)-labeled DNA hairpin probe was immobilized on the surface of Ag/Si CPA substrate, and SERS signal detection was performed for getting the corresponding dose-response curve after complementary hybridization with various concentration of microRNA-106 a. The results demonstrate that the detection of miRNA-106 a, based on the SERS characteristic of Ag/Si CPA substrate, exhibits the advantages of specificity and high sensitivity with the limit of detection of 0.917 fmol·L-1 in the detection range of 1 fmol·L-1-100 pmol·L-1. In addition, compared with the real-time fluorescence quantitative polynucleotide chain reaction(RT-qPCR) method, not only the detection results are consistent, but the detection method based on SERS spectroscopy has a higher sensitivity.