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Suppressing the background activity of hemin for boosting the sensitivity of DNAzyme-based biosensors by SYBR Green I.
Biosensors and Bioelectronics ( IF 12.6 ) Pub Date : 2020-09-09 , DOI: 10.1016/j.bios.2020.112603
Chi Zhang 1 , Houchun Zhang 1 , Peng Wu 2 , Xinfeng Zhang 3 , Juewen Liu 4
Affiliation  

Peroxidase-like DNAzymes have been extensively used to replace horseradish peroxidase (HRP) for developing biosensors for signal amplification. However, the background activity from the cofactor (i.e., free hemin) has limited the sensitivity of such sensors. Herein, we aim to find an inhibitor for hemin to suppress the background signal, and a classic split DNAzyme-based sensor was used to detect a complementary DNA oligonucleotide. After screening a series of dyes, SYBR Green I (SG, one of the DNA stanning dyes) was selected for suppressing the background. Simply by adding 0.84 μM SG, the background from 50 nM hemin was suppressed over 30-fold. The suppression was caused by the interaction between SG and hemin. In the presence of the target DNA, the formed duplex region and G-quadruplex structure can better bind SG and hemin respectively, thus preventing the interaction between them and showing a high activity of the DNAzyme. The optimized sensor showed a detection limit of 3.8 pM for the target DNA (p53 gene). In addition, the backgrounds from chemiluminescence, colorimetric and fluorescence sensing modes can all be reduced by adding SG to the split DNAzyme system. The suppression of the background of peroxidase DNAzymes is a critical step towards practical use of related biosensors.



中文翻译:

通过SYBR Green I抑制血红素的背景活性以提高基于DNAzyme的生物传感器的敏感性。

类似过氧化物酶的DNA酶已被广泛用于替代辣根过氧化物酶(HRP),以开发用于信号放大的生物传感器。但是,来自辅因子的背景活性(即游离血红素)限制了此类传感器的灵敏度。在本文中,我们旨在寻找一种抑制血红素的抑制剂,以抑制背景信号,并使用经典的基于分裂DNAzyme的传感器检测互补的DNA寡核苷酸。筛选了一系列染料后,选择了SYBR Green I(SG,一种DNA锡染染料)来抑制背景。只需添加0.84μMSG,即可将50 nM血红素的背景抑制30倍以上。该抑制是由SG和血红素之间的相互作用引起的。在目标DNA存在的情况下,形成的双链体区域和G-四链体结构可以分别更好地结合SG和血红素,因此阻止了它们之间的相互作用,并显示了DNA酶的高活性。优化的传感器对目标DNA(p53基因)的检测极限为3.8 pM。此外,化学发光,比色和荧光传感模式的背景都可以通过在分离的DNAzyme系统中添加SG来减少。过氧化物酶DNA酶本底的抑制是实际使用相关生物传感器的关键步骤。

更新日期:2020-09-15
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