Zandieh Mohamad, Liu Juewen
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Centre for Eye and Vision Research, 17W Hong Kong Science Park, Hong Kong, SAR China.
Bioconjug Chem. 2021 Apr 21;32(4):801-809. doi: 10.1021/acs.bioconjchem.1c00078. Epub 2021 Mar 12.
Magnetic nanoparticles have been widely used for the separation of biomolecules for biological applications due to the mild and efficient separation process. In previous studies, core-shell magnetic nanoparticles (NPs) were designed for DNA extraction without much sequence specificity. In this work, to achieve highly selective DNA extraction, we designed a core-shell magnetic structure by coating polydopamine (PDA) on FeO NPs. Without divalent metal ions, PDA does not adsorb DNA at neutral pH. The FeO@PDA NPs were then functionalized with spherical nucleic acids (SNA) to provide a high density of probe DNA. FeO@PDA@SNA was also compared with when a linear SH-DNA was covalently attached to the NPs surface, showing a higher density of the probe SNA than SH-DNA can be loaded on the NPs in a remarkably shorter time. Nonspecific DNA extraction was thoroughly inhibited by both probes. DNA extraction by the FeO@PDA@SNA was more effective as well as 5-fold faster than by the FeO@PDA@SH-DNA, probably due to the favorable standing conformation of DNA strands in SNA. Moreover, extraction by FeO@PDA@SNA showed high robustness in fetal bovine serum, and the same design can be used for selective detection of DNA. Finally, the method was also demonstrated on silica NPs and WS nanosheets for coating with PDA and SNA. Altogether, our findings revealed an interesting and general surface modification strategy using PDA@SNA conjugates for sequence-specific DNA extraction.
由于分离过程温和且高效，磁性纳米颗粒已被广泛用于生物应用中生物分子的分离。在先前的研究中，核壳磁性纳米颗粒（NPs）被设计用于DNA提取，且没有太多序列特异性。在这项工作中，为了实现高度选择性的DNA提取，我们通过在FeO NPs上包覆聚多巴胺（PDA）设计了一种核壳磁性结构。在没有二价金属离子的情况下，PDA在中性pH值下不吸附DNA。然后用球形核酸（SNA）对FeO@PDA NPs进行功能化，以提供高密度的探针DNA。还将FeO@PDA@SNA与将线性SH-DNA共价连接到NPs表面的情况进行了比较，结果表明，与SH-DNA相比，探针SNA可以在显著更短的时间内以更高的密度负载在NPs上。两种探针都能完全抑制非特异性DNA提取。FeO@PDA@SNA提取DNA的效果更好，速度比FeO@PDA@SH-DNA快5倍，这可能是由于SNA中DNA链具有有利的直立构象。此外，FeO@PDA@SNA在胎牛血清中的提取表现出很高的稳健性，并且相同的设计可用于DNA的选择性检测。最后，该方法也在二氧化硅NPs和WS纳米片上进行了验证，用于包覆PDA和SNA。总之，我们的研究结果揭示了一种有趣且通用的表面修饰策略，即使用PDA@SNA缀合物进行序列特异性DNA提取。
