Department of Chemistry , Loughborough University , Loughborough , Leicestershire LE11 3TU , United Kingdom.
Anal Chem. 2019 Sep 3;91(17):11291-11296. doi: 10.1021/acs.analchem.9b02353. Epub 2019 Aug 15.
The use of nanocarriers within resistive pulse sensing facilitates the detection and quantification of analytes. To date the field has been dominated by polyionic carriers or nanomaterials. Together they combine the recognition elements of a ligand with a stable support, facilitating the sample handling, analysis times, and multiplex detection. Here we develop the use of peptide-functionalized superparamagnetic nanocarriers to extract and quantify metal ions in solution. The interaction between nickel and the peptide ligand is measured as a change in translocation velocity of the carrier. The magnitude of change is proportional to the concentration of the metal ions in solution. Unlike DNA aptamers where a change in the tertiary structure and the folding of the polyanionic backbone influences the carrier velocity, the peptides here had a lower net charge under the assay conditions. To try and enhance the signal we engineered charged groups within the peptide to explore the effects on the signal. In all cases the metal ion binding dominated the velocity of the carrier. The assay was shown to work across 3 orders of magnitude and can detect Ni in the presence of some other heavy metal ions. We demonstrate this by quantifying Ni in both tap and pond water. The work allows for future multiplexed sensing strategies using both peptides and DNA aptamers in resistive pulse sensors.
纳米载体在电阻脉冲感应中的应用有助于分析物的检测和定量。迄今为止，该领域一直由聚离子载体或纳米材料主导。它们共同将配体的识别元件与稳定的载体结合在一起，从而方便了样品处理、分析时间和多重检测。在这里，我们开发了使用肽功能化超顺磁纳米载体来提取和定量溶液中的金属离子。载体迁移速度的变化可测量镍与肽配体之间的相互作用。变化的幅度与溶液中金属离子的浓度成正比。与 DNA 适体不同，DNA 适体的三级结构和多阴离子骨架的折叠变化会影响载体速度，而这里的肽在测定条件下的净电荷较低。为了尝试增强信号，我们在肽中设计了带电基团，以探讨其对信号的影响。在所有情况下，金属离子结合都主导着载体的速度。该测定方法可在 3 个数量级范围内工作，并可在存在一些其他重金属离子的情况下检测 Ni。我们通过在自来水和池塘水中定量测定 Ni 来证明这一点。这项工作为电阻脉冲传感器中使用肽和 DNA 适体的未来多重感应策略提供了可能。
