Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO, Brazil.
Nanotechnology Research Centre, National Research Council of Canada, Edmonton, AB, Canada.
Anal Chim Acta. 2023 May 8;1254:341077. doi: 10.1016/j.aca.2023.341077. Epub 2023 Mar 15.
Digital microfluidics (DMF) is a versatile lab-on-a-chip platform that allows integration with several types of sensors and detection techniques, including colorimetric sensors. Here, we propose, for the first time, the integration of DMF chips into a mini studio containing a 3D-printed holder with previously fixed UV-LEDs to promote sample degradation on the chip surface before a complete analytical procedure involving reagent mixture, colorimetric reaction, and detection through a webcam integrated on the equipment. As a proof-of-concept, the feasibility of the integrated system was successfully through the indirect analysis of S-nitrosocysteine (CySNO) in biological samples. For this purpose, UV-LEDs were explored to perform the photolytic cleavage of CySNO, thus generating nitrite and subproducts directly on DMF chip. Nitrite was then colorimetrically detected based on a modified Griess reaction, in which reagents were prepared through a programable movement of droplets on DMF devices. The assembling and the experimental parameters were optimized, and the proposed integration exhibited a satisfactory correlation with the results acquired using a desktop scanner. Under the optimal experimental conditions, the obtained CySNO degradation to nitrite was 96%. Considering the analytical parameters, the proposed approach revealed linear behavior in the CySNO concentration range between 12.5 and 400 μmol L and a limit of detection equal to 2.8 μmol L. Synthetic serum and human plasma samples were successfully analyzed, and the achieved results did not statistically differ from the data recorded by spectrophotometry at the confidence level of 95%, thus indicating the huge potential of the integration between DMF and mini studio to promote complete analysis of lowmolecular weight compounds.
数字微流控（DMF）是一种多功能的芯片实验室平台，允许与多种类型的传感器和检测技术集成，包括比色传感器。在这里，我们首次提出将 DMF 芯片集成到一个迷你工作室中，该工作室包含一个 3D 打印的支架，其中预先固定了 UV-LED，以在进行涉及试剂混合物、比色反应和通过集成在设备上的网络摄像头进行检测的完整分析程序之前，促进样品在芯片表面降解。作为概念验证，成功地通过间接分析生物样品中的 S-亚硝基半胱氨酸（CySNO）证明了集成系统的可行性。为此，探索了 UV-LED 来进行 CySNO 的光解断裂，从而直接在 DMF 芯片上生成亚硝酸盐和副产物。然后基于改良的格里斯反应通过比色法检测亚硝酸盐，其中试剂是通过在 DMF 设备上的可编程液滴运动来制备的。优化了组装和实验参数，所提出的集成与使用台式扫描仪获得的结果具有良好的相关性。在最佳实验条件下，获得的 CySNO 降解为亚硝酸盐的效率为 96%。考虑到分析参数，该方法在 CySNO 浓度范围为 12.5 至 400 μmol L 之间表现出线性行为，检测限等于 2.8 μmol L。成功分析了合成血清和人血浆样品，获得的结果与分光光度法记录的数据在 95%置信水平下没有统计学差异，这表明 DMF 与迷你工作室之间的集成具有促进低分子量化合物完全分析的巨大潜力。
