The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , People's Republic of China.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu 210023 , People's Republic of China.
Anal Chem. 2019 Mar 5;91(5):3619-3627. doi: 10.1021/acs.analchem.8b05610. Epub 2019 Feb 21.
Human telomerase RNA (hTR), an important biomarker for cancer diagnosis, is the template for the synthesis of telomeric DNA repeats and is found to be 7-fold overexpressed in tumor cells. Herein, we present a photoelectrochemical (PEC) biosensor for hTR detection coupled with a novel amplification strategy based on cascades of catalytic hairpin assembly (CHA) and hyperbranched hybridization chain reaction (HB-HCR). At the electrode surface, thiolated hairpin 1 probes were immobilized on deposited CdS nanoparticles via a Cd-S bond. In the presence of target hTR, a CHA reaction was triggered and the exposing of trigger1 could further initiate an HB-HCR reaction to form abundant hemin/G-quadruplex DNAzymes containing dendritic DNA structure. The DNAzymes' catalytic precipitation of 4-chloro-1-naphthol (4-CN) by HO subsequently took place on the surface of the PEC electrode and efficiently suppressed the photocurrent output. Therefore, the change of photocurrent response had a positive linear relationship with logarithmic value of hTR concentration varying from 200 fM to 20.0 nM with a limit of detection (LOD) of 17.0 fM. The LOD for CHA/HB-HCR was about 8.8-fold lower than that of CHA/linear-branched HCR (CHA/LB-HCR) and 547-fold lower than that of CHA. By coupling the feature of high signal amplification capacity for DNA nanotechnology, a prominently stable, reproducible, and selective PEC biosensor was successfully constructed and applied in hTR detection.
人端粒酶 RNA（hTR）是癌症诊断的重要生物标志物，它是端粒 DNA 重复合成的模板，在肿瘤细胞中表达上调 7 倍。在此，我们提出了一种光电化学（PEC）生物传感器，用于 hTR 的检测，并结合了一种基于级联催化发夹组装（CHA）和超支化杂交链式反应（HB-HCR）的新型放大策略。在电极表面，巯基化发夹 1 探针通过 Cd-S 键固定在沉积的 CdS 纳米粒子上。在存在靶标 hTR 的情况下，引发 CHA 反应，并且暴露的 trigger1 可以进一步引发 HB-HCR 反应，形成含有树枝状 DNA 结构的丰富血红素/G-四链体 DNA 酶。随后，DNA 酶通过 HO 催化沉淀 4-氯-1-萘酚（4-CN）在 PEC 电极表面发生，并有效地抑制了光电流输出。因此，光电流响应的变化与 hTR 浓度的对数呈正线性关系，浓度范围从 200 fM 到 20.0 nM，检测限（LOD）为 17.0 fM。与 CHA/LB-HCR 相比，CHA/HB-HCR 的 LOD 约低 8.8 倍，与 CHA 相比，LOD 低 547 倍。通过结合 DNA 纳米技术的高信号放大能力的特点，成功构建了一种显著稳定、可重现和选择性的 PEC 生物传感器，并应用于 hTR 的检测。
