Department of Chemical Science and Technologies , University of Rome "Tor Vergata" , Via della Ricerca Scientifica 1 , 00133 Rome , Italy.
Anal Chem. 2018 Nov 20;90(22):13680-13686. doi: 10.1021/acs.analchem.8b04052. Epub 2018 Oct 30.
The detection of double stranded DNA (dsDNA) is often associated with the use of laboratory-bound approaches and/or with the prior generation of single stranded DNA (ssDNA), making these methods not suitable for in situ monitoring, i.e., point-of-care diagnostics. Screen-printed technology, coupled to the use of triplex forming oligonucleotides (TFO) as the recognizing probes, offers a great possibility toward the development of portable analytical tools. Moreover, the continuous demand for sustainable processes and waste lowering have highlighted the role of paper-based substrates for manufacturing easy-to-use, low-cost, and sustainable electrochemical devices. In this work, filter paper and copy paper have been utilized to produce E-DNA strips. Gold nanoparticles (AuNPs) have been exploited to immobilize the methylene blue (MB)-tagged TFO and to enhance the charge transfer kinetics at the electrode surface. Both paper-based substrates have been electrochemically characterized, and in addition, the effect of the amount of waxed layers has been evaluated. The paper-based E-DNA strips have been challenged toward the detection of three model targets, obtaining 3 and 7 nM as the detection limit, respectively, for single and double stranded sequences. The repeatability of the manufacturing (homemade) process has been evaluated with a relative standard deviation of approximately 10%. The effectiveness of the filter paper-based platform has been also evaluated in undiluted serum obtaining a similar value of the detection limit (compared to the measurements carried out in buffer solution). In addition, a synthetic PCR amplified dsDNA sequence, related to HIV, has been detected in serum samples.
双链 DNA（dsDNA）的检测通常与实验室相关的方法的使用以及单链 DNA（ssDNA）的预先生成相关，这使得这些方法不适合原位监测，即即时诊断。丝网印刷技术与三链形成寡核苷酸（TFO）作为识别探针的结合，为开发便携式分析工具提供了巨大的可能性。此外，对可持续工艺和减少废物的持续需求突出了纸基基底在制造易于使用、低成本和可持续电化学器件方面的作用。在这项工作中，滤纸和复印纸已被用于制造 E-DNA 条。金纳米粒子（AuNPs）被用来固定亚甲基蓝（MB）标记的 TFO，并增强电极表面的电荷转移动力学。两种纸基基底都进行了电化学表征，此外，还评估了蜡层数量的影响。纸基 E-DNA 条已用于检测三个模型靶标，分别获得 3 和 7 nM 的单链和双链序列的检测限。制造（自制）过程的重复性用大约 10%的相对标准偏差进行了评估。还评估了滤纸基平台在未稀释血清中的有效性，获得了与在缓冲溶液中进行的测量相似的检测限值。此外，还在血清样本中检测到与 HIV 相关的合成 PCR 扩增的 dsDNA 序列。
