Department of Nanoengineering, University of California San Diego, La Jolla, CA 92093, USA.
Talanta. 2011 Sep 15;85(3):1330-7. doi: 10.1016/j.talanta.2011.06.012. Epub 2011 Jun 21.
The development of rapid, low-cost and reliable diagnostic methods is crucial for the identification and treatment of many diseases. Screen-printed gold electrodes (Au/SPEs), coated with a ternary monolayer interface, involving hexanedithiol (HDT), a specific thiolated capture probe (SHCP), and 6-mercapto-1 hexanol (MCH) (SHCP/HDT/MCH) are shown here to offer direct and sensitive detection of nucleic acid hybridization events in untreated raw biological samples (serum, urine and crude bacterial lysate solutions). The composition of the ternary monolayer was modified and tailored to the surface of the Au/SPE. The resulting SHCP/HDT/MCH monolayer has demonstrated to be extremely useful for enhancing the performance of disposable nucleic acid sensors based on screen-printed electrodes. Compared to common SHCP/MCH binary interfaces, the new ternary self-assembled monolayer (SAM) resulted in a 10-fold improvement in the signal (S)-to-noise (N) ratio (S/N) for 1 nM target DNA. The SHCP/HDT/MCH-modified Au/SPEs allowed the direct quantification of the target DNA down to 25 pM (0.25 fmol) and 100 pM (1 fmol) in undiluted/untreated serum and urine samples, respectively, and of 16S rRNA Escherichia coli (E. coli) corresponding to 3000 CFU μL(-1) in raw cell lysate samples. The new SAM-coated screen-printed electrodes also displayed favorable non-fouling properties after a 24h exposure to raw human serum and urine samples, offering great promise as cost-effective nucleic acid sensors for a wide range of decentralized genetic tests.
快速、低成本且可靠的诊断方法的发展对于许多疾病的识别和治疗至关重要。本文展示了经修饰的印刷金电极（Au/SPE），其表面涂覆有涉及己二硫醇（HDT）、特定硫醇化捕获探针（SHCP）和 6-巯基-1-己醇（MCH）的三元单层界面（SHCP/HDT/MCH），可直接且灵敏地检测未经处理的原始生物样品（血清、尿液和粗细菌裂解液）中的核酸杂交事件。三元单层的组成经过修饰和适配 Au/SPE 的表面。所得的 SHCP/HDT/MCH 单层对于增强基于印刷电极的一次性核酸传感器的性能非常有用。与常见的 SHCP/MCH 二元界面相比，新的三元自组装单层（SAM）使信号（S）与噪声（N）比（S/N）提高了 10 倍，针对 1 nM 靶 DNA 的 S/N 比提高了 10 倍。SHCP/HDT/MCH 修饰的 Au/SPE 允许直接在未经稀释/未经处理的血清和尿液样品中定量检测靶 DNA，最低检测限分别为 25 pM（0.25 fmol）和 100 pM（1 fmol），在原始细胞裂解液样品中可检测到对应 16S rRNA 大肠杆菌（E. coli）的浓度为 3000 CFU μL(-1)。新的 SAM 涂覆的印刷电极在暴露于原始人血清和尿液样品 24 小时后还表现出良好的抗污染性能，有望成为用于各种分散式基因检测的经济高效的核酸传感器。
