Department of Bioanalytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland.
Int J Mol Sci. 2020 Nov 1;21(21):8190. doi: 10.3390/ijms21218190.
Here, we report the synthesis of a quantum dot (QD)-DNA covalent conjugate to be used as an HO-free DNAzyme system with oxidase activity. Amino-coupling conjugation was carried out between amino-modified oligonucleotides (CatG4-NH) and carboxylated quantum dots (CdTe@COOH QDs). The obtained products were characterized by spectroscopic methods (UV-Vis, fluorescence, circular dichroizm (CD), and IR) and the transmission electron microscopy (TEM) technique. A QD-DNA system with a low polydispersity and high stability in aqueous solutions was successfully obtained. The catalytic activity of the QD-DNA conjugate was examined with Amplex Red and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate)) indicators using reactive oxygen species (ROS) generated by visible light irradiation. The synthesized QD-DNAzyme exhibited enhanced catalytic activity compared with the reference system (a mixture of QDs and DNAzyme). This proved the assumption that the covalent attachment of DNAzyme to the surface of QD resulted in a beneficial effect on its catalytic activity. The results proved that the QD-DNAzyme system can be used for generation of the signal by light irradiation. The light-induced oxidase activity of the conjugate was demonstrated, proving that the QD-DNAzyme system can be useful for the development of new cellular bioassays, e.g., for the determination of oxygen radical scavengers.
在这里，我们报告了一种量子点（QD）-DNA 共价缀合物的合成，该缀合物可用作具有氧化酶活性的无 HO DNA 酶系统。在氨基修饰的寡核苷酸（CatG4-NH）和羧基化量子点（CdTe@COOH QDs）之间进行了氨基偶联缀合。通过光谱方法（UV-Vis、荧光、圆二色性（CD）和 IR）和透射电子显微镜（TEM）技术对所得产物进行了表征。成功获得了在水溶液中具有低多分散性和高稳定性的 QD-DNA 系统。使用 Amplex Red 和 ABTS（2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate)）指示剂，通过可见光照射产生的活性氧（ROS）检查了 QD-DNA 缀合物的催化活性。与参考系统（QD 和 DNA 酶的混合物）相比，合成的 QD-DNA 酶表现出增强的催化活性。这证明了将 DNA 酶共价连接到 QD 表面会对其催化活性产生有利影响的假设。结果证明，QD-DNA 酶系统可用于通过光照产生信号。证明了缀合物的光诱导氧化酶活性，证明了 QD-DNA 酶系统可用于开发新的细胞生物测定法，例如用于测定氧自由基清除剂。
