基于海绵状纳米多孔金盘的G-四链体表面增强拉曼散射传感器

G-4 chain surface enhanced Raman scattering sensor based on spongy nano-porous gold plate

G-四链体是由富G序列的DNA折叠构成,在转录调节、DNA复制和基因组稳定性方面都发挥着重要作用.然而,很多G-四链体的识别技术都局限于荧光检测技术.由于目前荧光技术灵敏度不足,而没有被广泛应用.针对这一问题,实验制备了一种海绵状纳米多孔金盘(Spongy nanoporous disks,SNPD),将其作为表面增强拉曼散射传感器(Surface enhanced Raman scattering sensor,SERS)的基底,以孔雀石绿(Malachite green,MG)作为信号分子,建立了一种高灵敏G-四链体SERS识别技术.SNPD直径约为360 nm,高度约为75 nm,内部孔径大小约为15 nm.其具有独特的海绵状结构,高密度的韧带和孔径结构,为表面等离子体共振提供了大量增强热点和结合位点,大大增强了MG信号分子的Raman振动峰,有力地提高了G-四链体的检测灵敏度,其检测限低至100 pmol/L.此外,研究发现G-四链体无需通过复杂的标记过程,能够特异性捕获MG至SNPD表面,而捕获作用并没有在ssDNA和dsDNA中发现,表明传感技术具有良好的选择性.

G-quadruplex,readily formed by the folding G-rich DNA,is supposed to have diverse of critical functions for transcriptional regulation,DNA replication and genome stability.However,restricted by insufficient sensitivity of fluorescence detection technique,a large number of G-quadruplex identification technologies are not widely used.To relief the problem,the unique spongy nanoporous disks(SNPD)was prepared and explored to establish a highly sensitive surface enhanced Raman scattering(SERS)sensor for G-quadruplexes identification,in which SNPD was used as the substrate of surface enhanced Raman scattering sensor and malachite green as the signal molecule.The SNPD has a diameter of 360 nm,a height of 75 nm and an internal pore size of 15 nm.Its unique spongy structure,abundant ligament structure and high density porous structure provided a great deal of enhanced hotspots as well as binding sites,greatly heightens the Raman vibration peak of MG signal molecule,and significantly improves the detection sensitivity of G-quadruplex,with the detection limit as low as 100 pmol/L.Besides,the G-quadruplexes could be utilized as scaffolds to capture MG molecules onto the surface of SNPD,without extra complicate labeling process.Such capture action was not found in ssDNA and dsDNA,indicating the good selectivity of the proposed SERS sensor.