Abstract

To monitor and manage hydrological systems such as brooks, streams, rivers, the use of tracers is a well-established process. Limited number of potential tracers such as salts, isotopes and dyes, make study of hydrological processes a challenge. Traditional tracers find limited use due to lack of multiplexed, multipoint tracing and background noise, among others. In this regard, DNA based tracers possess remarkable advantages including, environmentally friendly, stability, and high sensitivity in addition to showing great potential in the synthesis of ideally unlimited number of unique tracers capable of multipoint tracing. To prevent unintentional losses in the environment during application and easy recovery for analysis, we hereby report DNA encapsulation in silica containing magnetic cores (iron oxide) of two different shapes—spheres and cubes. The iron oxide nanoparticles having size range 10–20 nm, have been synthesized using co-precipitation of iron salts or thermal decomposition of iron oleate precursor in the presence of oleic acid or sodium oleate. Physico-chemical properties such as size, zeta potential, magnetism etc. of the iron oxide nanoparticles have been optimized using different ligands for effective binding of dsDNA, followed by silanization. We report for the first time the effect of surface coating on the magnetic properties of the iron oxide nanoparticles at each stage of functionalization, culminating in silica shells. Efficiency of encapsulation of three different dsDNA molecules has been studied using quantitative polymerase chain reaction (qPCR). Our results show that our DNA based magnetic tracers are excellent candidates for hydrological monitoring with easy recoverability and high signal amplification.

Graphic Abstract

中文翻译：

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磁性纳米粒子独特的DNA示踪剂：功能化对理化性质的影响

摘要

为了监视和管理溪流，溪流，河流等水文系统，使用示踪剂是一个公认的过程。数量有限的潜在示踪剂，例如盐，同位素和染料，使水文过程的研究成为一个挑战。由于缺乏多路复用，多点跟踪和背景噪声，传统跟踪器的使用受到限制。在这方面，基于DNA的示踪剂除了在合成无限数量的能够进行多点示踪的独特示踪剂方面显示出巨大潜力外，还具有环保，稳定性和高灵敏度等显着优势。为了防止在应用过程中环境的意外损失以及易于回收以进行分析，我们特此报告将DNA封装在含有两种不同形状的磁芯（氧化铁）的二氧化硅中（球形和立方体）。使用油盐或油酸钠存在下的铁盐共沉淀或油酸铁前体的热分解合成了尺寸为10–20 nm的氧化铁纳米颗粒。已使用不同的配体优化了dsDNA的有效结合，然后进行硅烷化，从而优化了氧化铁纳米颗粒的物理化学性质（例如大小，ζ电位，磁性等）。我们首次报道了在功能化的各个阶段，表面涂层对氧化铁纳米颗粒磁性的影响，最终达到了二氧化硅壳的目的。已使用定量聚合酶链反应（qPCR）研究了三种不同dsDNA分子的包封效率。

图形摘要