Fu Yingzi, Yuan Ruo, Xu Lan, Chai Yaqin, Liu Yan, Tang Dianping, Zhang Ying
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest China Normal University, Chongqing 400700, PR China.
J Biochem Biophys Methods. 2005 Feb 28;62(2):163-74. doi: 10.1016/j.jbbm.2004.11.003. Epub 2004 Dec 13.
A novel method for fabrication of DNA biosensors has been developed by means of self-assembling colloidal Ag (Ag) to a thiol-containing sol-gel network. The thiol groups of 3-mercaptopropyltrimethoxysilane (MPTS) serve as binding sites for the covalent attachment to gold electrode surface. Then the one-dimensional network of silane unites (1dMPTS) was combined together into a two-dimensional sol-gel network (2dMPTS) by dipping into aqueous NaOH. The second silane layer (B2dMPTS) was formed by immersing electrodes back into the MPTS solution overnight, and then the Ag nanoparticles were chemisorbed onto the thiol groups of the second silane layer. Finally, the mercapto oligonucleotide was self-assembled onto the surface via the Ag nanoparticles. The modified process was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). In addition, we utilized the impedance spectroscopy as a platform for DNA sensing assay. The factors influencing the performance of the resulting biosensor were studied in detail. The linear range of the biosensor was from 8.0 x 10(-9) to 1.0 x 10(-6) M with a detection limit of 4.0 x 10(-9) M at 3sigma. In addition, the experiment results indicate that oligonucleotide immobilized on this way exhibits a good sensitivity and selectivity, high stability and a long-term maintenance of bioactivity.
一种通过将胶体银（Ag）自组装到含硫醇的溶胶 - 凝胶网络中来制造DNA生物传感器的新方法已被开发出来。3 - 巯基丙基三甲氧基硅烷（MPTS）的硫醇基团作为与金电极表面共价连接的结合位点。然后通过浸入氢氧化钠水溶液将一维硅烷单元网络（1dMPTS）组合成二维溶胶 - 凝胶网络（2dMPTS）。通过将电极重新浸入MPTS溶液过夜形成第二硅烷层（B2dMPTS），然后将银纳米颗粒化学吸附到第二硅烷层的硫醇基团上。最后，巯基寡核苷酸通过银纳米颗粒自组装到表面上。修饰过程通过电化学阻抗谱（EIS）和循环伏安法（CV）进行表征。此外，我们利用阻抗谱作为DNA传感检测的平台。详细研究了影响所得生物传感器性能的因素。该生物传感器的线性范围为8.0×10^(-9)至1.0×10^(-6) M，在3σ时检测限为4.0×10^(-9) M。此外，实验结果表明，以这种方式固定的寡核苷酸表现出良好的灵敏度和选择性、高稳定性以及生物活性的长期维持。
