Park Joon Soo, Goo Nam-In, Kim Dong-Eun
Department of Bioscience and Biotechnology, Konkuk University , Seoul 143-701, Republic of Korea.
Langmuir. 2014 Oct 28;30(42):12587-95. doi: 10.1021/la503401d. Epub 2014 Oct 15.
Graphene oxide (GO) adsorbing a fluorophore-labeled single-stranded (ss) DNA serves as a sensor system because subsequent desorption of the adsorbed probe DNA from GO in the presence of complementary target DNA enhances the fluorescence. In this study, we investigated the interaction of single- and double-stranded (ds) DNAs with GO by using a fluorescently labeled DNA probe. Although GO is known to preferentially interact with ssDNA, we found that dsDNA can also be adsorbed on GO, albeit with lower affinity. Furthermore, the status of ssDNA or dsDNA previously adsorbed on the GO surface was investigated by adding complementary or noncomplementary DNA (cDNA or non-cDNA) to the adsorption complex. We observed that hybridization occurred between the cDNA and the probe DNA on the GO surface. On the basis of the kinetics driven by the incoming additional DNA, we propose a mechanism for the desorption of the preadsorbed probe DNA from the GO surface: the desorption of the GO-adsorbed DNA was facilitated following its hybridization with cDNA on the GO surface; when the GO surface was almost saturated with the adsorbed DNA, nonspecific desorption dominated the process through a simple displacement of the GO-adsorbed DNA molecules by the incoming DNA molecules because of the law of mass action. Our results can be applied to design appropriate DNA probes and to choose proper GO concentrations for experimental setups to improve specific signaling in many biosensor systems based on the GO platform.
吸附有荧光团标记的单链（ss）DNA的氧化石墨烯（GO）可作为一种传感系统，因为在存在互补靶DNA的情况下，吸附的探针DNA随后从GO上解吸会增强荧光。在本研究中，我们通过使用荧光标记的DNA探针研究了单链和双链（ds）DNA与GO的相互作用。尽管已知GO优先与ssDNA相互作用，但我们发现dsDNA也能吸附在GO上，尽管亲和力较低。此外，通过向吸附复合物中加入互补或非互补DNA（cDNA或非cDNA），研究了先前吸附在GO表面的ssDNA或dsDNA的状态。我们观察到cDNA与GO表面的探针DNA之间发生了杂交。基于引入的额外DNA驱动的动力学，我们提出了预吸附的探针DNA从GO表面解吸的机制：GO吸附的DNA与GO表面的cDNA杂交后，其解吸变得容易；当GO表面几乎被吸附的DNA饱和时，由于质量作用定律，非特异性解吸通过引入的DNA分子简单取代GO吸附的DNA分子而主导该过程。我们的结果可应用于设计合适的DNA探针，并为实验设置选择合适的GO浓度，以改善基于GO平台的许多生物传感器系统中的特异性信号传导。
