Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcala, 28802, Alcala de Henares, Madrid, Spain.
Department of Chemistry in Pharmaceutical Sciences, Analytical Chemistry, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
Lab Chip. 2024 Sep 10;24(18):4253-4263. doi: 10.1039/d4lc00398e.
A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability of the results due to an independent signal principle and processing. The μPADs were validated by analyzing a certified reference material, showing excellent accuracy ( ≤ 5%) and precision (RSD ≤ 2%). Then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation ( = 0.96, < 0.05) and no significant differences were found between them (slope 1.0 ± 0.1 and the intercept 1 ± 4, < 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical μPAD is a promising ready to use reagent-free device for the testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic strokes, where the decision-time is crucial for the patient's survival.
一种新型的双通道比色电化学微流控纸基分析装置（dual μPAD）被开发出来，用于评估缺血性脑卒中患者样本中的转铁蛋白饱和度（TSAT）。TSAT 通过比色法测量的转铁蛋白结合铁与电化学法测量的总铁结合能力的比值来计算。为此，巧妙地设计了一个 μPAD，它集成了比色和电化学检测储液器，通过一个充当化学反应器的微通道进行通信，并具有预加载/存储能力（无试剂装置）。这种方法允许同时双通道和同时测定这两个参数，由于独立的信号原理和处理，提高了结果的可靠性。通过分析认证参考物质对 μPAD 进行了验证，结果显示具有出色的准确性（≤5%）和精密度（RSD ≤ 2%）。然后将它们应用于分析缺血性脑卒中患者的诊断血清样本。结果与无干扰方法（urea-PAGE）提供的结果进行了比较。令人印象深刻的是，两种方法之间具有良好的相关性（= 0.96， < 0.05），并且没有发现它们之间存在显著差异（斜率 1.0 ± 0.1，截距 1 ± 4， < 0.05），这表明在使用仅 90 μL 的临床样本且与 urea-PAGE 方法所需的 18 小时相比不到 90 分钟的情况下，我们的方法在分析来自缺血性脑卒中患者的复杂样本时具有出色的准确性。开发的完全集成的比色电化学 μPAD 是一种很有前途的即用型无试剂装置，可用于测试 TSAT，这有助于医生快速诊断和预测缺血性脑卒中，而决策时间对患者的生存至关重要。
