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Small. 2014 Mar 26;10(6):1202-11. doi: 10.1002/smll.201301824. Epub 2013 Dec 13.
A magnetic nanosensor-based method is described to screen a library of drugs for potential binding to toxins. Screening is performed by measuring changes in the magnetic relaxation signal of the nanosensors (bMR nanosensors) in aqueous suspension upon addition of the toxin. The Anthrax lethal factor (ALF) is selected as a model toxin to test the ability of our bMR nanosensor-based screening method to identify potential inhibitors of the toxin. Out of 30 molecules screened, sulindac, naproxen and fusaric acid are found to bind LF, with dissociation constants in the low micromolar range. Further biological analysis of the free molecules in solution indicate that sulindac and its metabolic products inhibited LF cytotoxicity to macrophages with IC50 values in the micromolar range. Meanwhile, fusaric acid is found to be less effective at inhibiting LF cytotoxicity, while naproxen does not inhibit LF toxicity. Most importantly, when the sulindac and fusaric acid-bMR nanosensors themselves are tested as LF inhibitors, as opposed to the corresponding free molecules, they are stronger inhibitors of LF with IC50 values in the nanomolar range. Taken together, these studies show that a bMR nanosensors-based assay can be used to screen known drugs and other small molecules for inhibitor of toxins. The method can be easily modified to screen for inhibitors of other molecular interactions and not only the selected free molecule can be study as potential inhibitors but also the bMR nanosensors themselves achieving greater inhibitory potential.
一种基于磁性纳米传感器的方法被描述用于筛选潜在与毒素结合的药物库。通过在加入毒素后测量水混悬液中纳米传感器（bMR 纳米传感器）的磁弛豫信号的变化来进行筛选。炭疽致死因子（ALF）被选为模型毒素，以测试我们基于 bMR 纳米传感器的筛选方法识别毒素潜在抑制剂的能力。在筛选的 30 种分子中，发现舒林酸、萘普生和 Fusaric 酸与 LF 结合，解离常数在低微摩尔范围内。进一步对溶液中游离分子的生物学分析表明，舒林酸及其代谢产物以 IC50 值在微摩尔范围内抑制 LF 对巨噬细胞的细胞毒性。同时，发现 Fusaric 酸在抑制 LF 细胞毒性方面的效果较差，而萘普生则不抑制 LF 毒性。最重要的是，当舒林酸和 Fusaric 酸-bMR 纳米传感器本身被用作 LF 抑制剂，而不是相应的游离分子时，它们对 LF 的抑制作用更强，IC50 值在纳摩尔范围内。总之，这些研究表明，基于 bMR 纳米传感器的测定法可用于筛选已知药物和其他小分子的毒素抑制剂。该方法可以很容易地修改为筛选其他分子相互作用的抑制剂，不仅可以研究选定的游离分子作为潜在抑制剂，还可以研究 bMR 纳米传感器本身，以实现更大的抑制潜力。
