Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Langmuir. 2023 Aug 22;39(33):11596-11602. doi: 10.1021/acs.langmuir.3c01066. Epub 2023 Aug 8.
Nanodiamonds (NDs) have attracted considerable attention owing to their quantum properties and versatility in biological applications. In this study, we systematically investigated the adsorption of DNA oligonucleotides onto NDs with three types of surface groups: carboxylated (COOH-), hydroxylated (OH-), and hydrogenated (H-). Among them, only the H-NDs showed fluorescence quenching property that is useful for real-time DNA adsorption kinetic studies. The effect of common metal ions on DNA adsorption was studied. In the presence of Na, the order of DNA adsorption efficiency was H- > OH- > COOH-, whereas all the NDs showed a similar DNA adsorption efficiency in the presence of divalent metal ions such as Ca and Zn. Desorption studies revealed that hydrogen bonding and metal-mediated interactions were dominant for the adsorption of DNA, and the H-NDs exhibited extraordinarily tight DNA adsorption. Finally, a fluorescently labeled DNA was adsorbed on NDs for DNA detection, and the COOH-NDs had the highest target specificity, and a detection limit of 1.4 nM was achieved. This study indicates the feasibility of using metal ions to mediate the physical adsorption of DNA to NDs and compares various NDs with graphene oxide for fundamental understanding.
纳米金刚石（NDs）因其量子特性和在生物应用中的多功能性而引起了相当大的关注。在这项研究中，我们系统地研究了三种表面基团（羧基化（COOH-）、羟基化（OH-）和氢化（H-））的 ND 对 DNA 寡核苷酸的吸附。其中，只有 H-NDs 表现出荧光猝灭特性，这对于实时 DNA 吸附动力学研究非常有用。研究了常见金属离子对 DNA 吸附的影响。在存在 Na 的情况下，DNA 吸附效率的顺序为 H- > OH- > COOH-，而在存在二价金属离子如 Ca 和 Zn 的情况下，所有 ND 都表现出相似的 DNA 吸附效率。解吸研究表明，氢键和金属介导的相互作用是 DNA 吸附的主要作用，而 H-NDs 则表现出非常紧密的 DNA 吸附。最后，将荧光标记的 DNA 吸附到 ND 上进行 DNA 检测，COOH-ND 具有最高的目标特异性，检测限达到 1.4 nM。这项研究表明，使用金属离子来介导 DNA 对 ND 的物理吸附是可行的，并比较了各种 ND 与氧化石墨烯，以进行基础理解。
