Identification of Molecular-Mimicry-Based Ligands for Cholera Diagnostics using Magnetic Relaxation
Identification of Molecular-Mimicry-Based Ligands for Cholera Diagnostics using Magnetic Relaxation
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DOI：
10.1021/bc100442q
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发表时间：
2011-02-01
影响因子：
4.7
通讯作者：
Perez, J. Manuel
中科院分区：
文献类型：
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作者：
Kaittanis, Charalambos;Banerjee, Tuhina;Perez, J. Manuel
当与合适的配体共价结合时，氧化铁纳米颗粒能够与特定的目标物结合。这种相互作用可通过磁弛豫测量，根据溶液的自旋 - 自旋弛豫时间（T2）的变化来检测。在本报告中，采用了一种分子模拟策略来识别与霍乱毒素B亚单位（CTB）结合的靶向配体。细胞表面的CTB受体神经节苷脂GM1包含一个部分由半乳糖和葡萄糖单元组成的五糖部分。因此我们预测CTB会将与碳水化合物偶联的氧化铁纳米颗粒识别为GM1模拟物，从而使T2弛豫时间产生可检测的变化。磁弛豫实验表明CTB与半乳糖偶联的纳米颗粒相互作用。通过使用游离的或与纳米颗粒偶联的半乳糖分子进行表面等离子体共振研究，证实了这种相互作用。然后将半乳糖偶联的纳米颗粒用作CTB传感器，检测限达到40皮摩尔。通过磁弛豫研究，我们发现CTB还与葡聚糖包被的纳米颗粒相互作用，并且表面等离子体共振研究也证实了这种相互作用。其他实验表明，葡聚糖包被的纳米颗粒也可用作CTB传感器，并且葡聚糖能够阻止CTB内化进入表达GM1的细胞。我们的工作表明，磁性纳米颗粒偶联物和磁弛豫检测可作为一种通过分子模拟识别靶向配体的简便快速的方法。此外，我们的结果显示，葡聚糖包被的纳米颗粒是一种用于CTB检测的低成本方法。
When covalently bound to an appropriate ligand, iron oxide nanoparticles can bind to a specific target of interest. This interaction can be detected through changes in the solution's spin spin relaxation times (T2) via magnetic relaxation measurements. In this report, a strategy of molecular mimicry was used in order to identify targeting ligands that bind to the cholera toxin B subunit (CTB). The cellular CTB-receptor, ganglioside GM1, contains a pentasaccharide moiety consisting in part of galactose and glucose units. We therefore predicted that CTB would recognize carbohydrate-conjugated iron oxide nanoparticles as GM1 mimics, thus producing a detectable change in the T2 relaxation times. Magnetic relaxation experiments demonstrated that CTB interacted with the galactose-conjugated nanoparticles. This interaction was confirmed via surface plasmon resonance studies using either the free or nanoparticle-conjugated galactose molecule. The galactose-conjugated nanoparticles were then used as CTB sensors achieving a detection limit of 40 pM. Via magnetic relaxation studies, we found that CTB also interacted with dextran-coated nanoparticles, and surface plasmon resonance studies also confirmed this interaction. Additional experiments demonstrated that the dextran-coated nanoparticle can also be used as CTB sensors and that dextran can prevent the internalization of CTB into GM1-expressing cells. Our work indicates that magnetic nanoparticle conjugates and magnetic relaxation detection can be used as a simple and fast method to identify targeting ligands via molecular mimicry. Furthermore, our results show that the dextran-coated nanoparticles represent a low-cost approach for CTB detection.