School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Anal Chem. 2010 Jun 15;82(12):5147-53. doi: 10.1021/ac100346z.
Three-dimensional gold nanoarchitecture was fabricated by layer-by-layer (LbL) deposition of gold nanoparticles (AuNPs) and multiwalled carbon nanotubes (MWCNTs) on a glass substrate for a highly sensitive plasmonic biosensor using a conventional UV-vis instrument. Carboxyl-functionalized MWCNTs were reacted with 3-mercaptopropyltriethoxysilane (MPTES) to introduce multiple thiol groups onto MWCNTs. A self-assembled monolayer (SAM) of AuNPs on a glass chip was sequentially dipped into MPTES-functionalized MWCNTs (MWCNT-Si-SH) and AuNPs to form multilayers of AuNPs on MWCNTs. Such three-dimensionally assembled AuNPs provided a large surface area and multiple binding sites within a few steps of modification and microporous structures of multilayered MWCNTs to allow a high accessibility of target molecules. It was shown that the bulk refractive index (RI) sensitivity of these multilayered AuNPs (three-dimensional chip) appeared to be 5.6 times better than that of a monolayer of AuNPs on a glass chip (two-dimensional chip). The three-dimensional chips were further used for a biomolecular binding study, showing a detection limit as low as 0.5 nM for streptavidin and 3.33 nM for anti-human serum albumin (HSA), both of which were approximately 20 times higher than the sensitivity of the two-dimensional chips.
通过在玻璃基底上逐层（LbL）沉积金纳米粒子（AuNPs）和多壁碳纳米管（MWCNTs），制备了三维金纳米结构，并用传统的紫外-可见仪器制作了高灵敏度的等离子体生物传感器。羧基功能化的 MWCNTs 与 3-巯丙基三乙氧基硅烷（MPTES）反应，在 MWCNTs 上引入多个巯基。玻璃芯片上的 AuNPs 自组装单层（SAM）依次浸入 MPTES 功能化的 MWCNTs（MWCNT-Si-SH）和 AuNPs 中，在 MWCNTs 上形成多层 AuNPs。这种三维组装的 AuNPs 提供了大的表面积和多个结合位点，仅需几步修饰和多层 MWCNTs 的微孔结构即可实现高靶分子的可及性。结果表明，这些多层 AuNPs（三维芯片）的体折射率（RI）灵敏度似乎比玻璃芯片上的单层 AuNPs（二维芯片）高 5.6 倍。进一步将三维芯片用于生物分子结合研究，对链霉亲和素的检测限低至 0.5 nM，对人血清白蛋白（HSA）的检测限低至 3.33 nM，均比二维芯片的灵敏度高约 20 倍。
