Uddin Rokon, Rena Graham, Hwu En-Te, Boisen Anja
Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech , Building 345 East, DK-2800 Kongens Lyngby, Denmark.
Department of Chemistry and Bioengineering, Tampere University of Technology , 33720, Tampere, Finland.
ACS Sens. 2017 Sep 22;2(9):1329-1336. doi: 10.1021/acssensors.7b00384. Epub 2017 Aug 18.
The mechanism of action (MOA) of the first line type-2 diabetes drug metformin remains unclear despite its widespread usage. However, recent evidence suggests that the mitochondrial copper (Cu)-binding action of metformin may contribute toward the drug's MOA. Here, we present a novel biosensing platform for investigating the MOA of metformin using a magnetic microbead-based agglutination assay which has allowed us to demonstrate for the first time the interaction between Cu and metformin at clinically relevant low micromolar concentrations of the drug, thus suggesting a potential pathway of metformin's blood-glucose lowering action. In this assay, cysteine-functionalized magnetic beadswere agglutinated in the presence of Cu due to cysteine's Cu-chelation property. Addition of clinically relevant doses of metformin resulted in disaggregation of Cu-bridged bead-clusters, whereas the effect of adding a closely related but blood-glucose neutral drug propanediimidamide (PDI) showed completely different responses to the clusters. The entire assay was integrated in an automated microfluidics platform with an advanced optical imaging unit by which we investigated these aggregation-disaggregation phenomena in a reliable, automated, and user-friendly fashion with total assay time of 17 min requiring a sample (metformin/PDI) volume of 30 μL. The marked difference of Cu-binding action between the blood-glucose lowering drug metformin and its inactive analogue PDI thus suggests that metformin's distinctive Cu-binding properties may be required for its effect on glucose homeostasis. The novel automated platform demonstrating this novel investigation thus holds the potential to be utilized for investigating significant and sensitive molecular interactions via magnetic bead-based agglutination assay.
尽管一线2型糖尿病药物二甲双胍已被广泛使用，但其作用机制仍不清楚。然而，最近的证据表明，二甲双胍的线粒体铜（Cu）结合作用可能有助于其作用机制。在此，我们提出了一种新型生物传感平台，用于使用基于磁微珠的凝集试验研究二甲双胍的作用机制，该试验首次使我们能够证明在临床相关的低微摩尔浓度药物下铜与二甲双胍之间的相互作用，从而提示了二甲双胍降低血糖作用的潜在途径。在该试验中，由于半胱氨酸的铜螯合特性，半胱氨酸功能化的磁珠在铜存在的情况下发生凝集。添加临床相关剂量的二甲双胍会导致铜桥接的珠簇解聚，而添加密切相关但对血糖无影响的药物丙二亚胺（PDI）的效果对簇显示出完全不同的反应。整个试验集成在一个带有先进光学成像单元的自动化微流控平台中，通过该平台我们以可靠、自动化且用户友好的方式研究了这些聚集 - 解聚现象，总试验时间为17分钟，所需样品（二甲双胍/PDI）体积为30μL。降血糖药物二甲双胍与其无活性类似物PDI之间铜结合作用的显著差异表明，二甲双胍独特的铜结合特性可能是其对葡萄糖稳态产生影响所必需的。展示这种新研究的新型自动化平台因此具有通过基于磁珠的凝集试验用于研究重要且敏感的分子相互作用的潜力。
