Medina-Sánchez Mariana, Miserere Sandrine, Cadevall Miquell, Merkoçi Arben
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona, Spain.
Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
Electrophoresis. 2016 Feb;37(3):432-7. doi: 10.1002/elps.201500288. Epub 2015 Nov 12.
In this study, we propose an electrochemical immunoassay into a disposable microfluidic platform, using quantum dots (QDs) as labels and their enhanced detection using bismuth as an alternative to mercury electrodes. CdSe@ZnS QDs were used to tag human IgG as a model protein and detected through highly sensitive stripping voltammetry of the dissolved metallic component (cadmium in our case). The modification of the screen printed carbon electrodes (SPCEs) was done by a simple electrodeposition of bismuth that was previously mixed with the sample containing QDs. A magneto-immunosandwich assay was performed using a micromixer. A magnet placed at its outlet in order to capture the magnetic beads used as solid support for the immunoassay. SPCEs were integrated at the end of the channel as detector. Different parameters such as bismuth concentration, flow rate, and incubation times, were optimized. The LOD for HIgG in presence of bismuth was 3.5 ng/mL with a RSD of 13.2%. This LOD was about 3.3-fold lower than the one obtained without bismuth. Furthermore, the sensitivity of the system was increased 100-fold respect to experiments carried out with classical screen-printed electrodes, both in presence of bismuth.
在本研究中，我们将一种电化学免疫分析方法引入一次性微流控平台，使用量子点（QDs）作为标记物，并利用铋替代汞电极来增强检测效果。以CdSe@ZnS量子点标记人免疫球蛋白G（human IgG）作为模型蛋白，并通过对溶解的金属成分（在我们的案例中为镉）进行高灵敏度溶出伏安法来检测。通过简单的铋电沉积对丝网印刷碳电极（SPCEs）进行修饰，铋预先与含有量子点的样品混合。使用微混合器进行磁免疫夹心分析。在其出口处放置一块磁铁，以捕获用作免疫分析固体支持物的磁珠。将丝网印刷碳电极集成在通道末端作为检测器。对铋浓度、流速和孵育时间等不同参数进行了优化。在有铋存在的情况下，人免疫球蛋白G的检测限为3.5 ng/mL，相对标准偏差为13.2%。该检测限比没有铋时获得的检测限低约3.3倍。此外，与在有铋存在的情况下使用传统丝网印刷电极进行的实验相比，该系统的灵敏度提高了100倍。
