Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá , E-28871, Alcalá de Henares, Madrid, Spain.
Anal Chem. 2013 Oct 1;85(19):9116-25. doi: 10.1021/ac402331v. Epub 2013 Sep 18.
Galactosemia is a rare disease that is diagnosed through the identification of different metabolite profiles. Therefore, the specific detection of galactose 1-phosphate (Gal 1-P), galactose (Gal), and uridyl diphosphate galactose (UDP-Gal) confirms type I, II, and III galactosemia diseases. Because of the low prevalence of galactosemia, sample availability is very scarce and screening methods to diagnose the illness are not commonly employed around the world. This work describes the coupling of microfluidic chips (MCs) to copper nanowires (CuNWs) as electrochemical detectors for the fast diagnosis of galactosemia in precious newborn urine samples. Conceptually speaking, we hypothesize that the inherent selectivity and sensitivity of CuNWs, toward galactosemia metabolites detection in connection with MC selectivity could allow the fast and simultaneous detection of the three galactosemia biomarkers, which implies the fast diagnosis of any galactosemia type in just one single analysis. Electrosynthesized CuNWs show a well-defined shape, with an average length of 6 μm and a width of 300 nm. The modified electrodes exhibited an enhanced electroactive surface area twice as high as the nonmodified ones. Very good intraelectrode repeatability with relative standard deviations (RSDs) of <8% (n = 10) and interelectrode reproducibility with RSDs of <12% (n = 5) were obtained, indicating an excellent stability of the nanoscaled electrochemical detector. Under optimum chemical (3 mM NaOH, pH 11.5), electrokinetic (separation voltage +750 V, injection +1500 V for 5 s) and electrochemical (E = +0.70 V in 3 mM NaOH, pH 11.5) conditions, galactosemia diseases were unequivocally identified, differentiating between type I, II, and III, using selected precious ill diagnosed newborn urine samples. Detection proceeded within less than 350 s, required negligible urine sample consumption, and displayed impressive signal-to-noise characteristics (ranging from 14 to 80) and micromolar limits of detection (LODs) much lower than the cutoff levels (Gal 1-P > 0.4 mM and Gal > 1.4 mM). Excellent reproducible recoveries (93%-107%, RSDs <6%) were also achieved, revealing the reliability of the approach. The significance of the newborn urine samples studied confirms the analytical potency of MC-CuNWs approach, enhancing the maturity of the microchip technology and opening new avenues for future implementation of screening applications in the field.
半乳糖血症是一种罕见的疾病，通过鉴定不同的代谢物谱来诊断。因此，特异性检测半乳糖 1-磷酸（Gal 1-P）、半乳糖（Gal）和尿苷二磷酸半乳糖（UDP-Gal）可确定 I 型、II 型和 III 型半乳糖血症。由于半乳糖血症的发病率较低，样本可用性非常稀缺，而且全球范围内也没有普遍采用用于诊断该病的筛查方法。本工作描述了将微流控芯片（MCs）与铜纳米线（CuNWs）偶联作为电化学探测器，用于快速诊断珍贵新生儿尿液样本中的半乳糖血症。从概念上讲，我们假设 CuNWs 对半乳糖血症代谢物检测的固有选择性和敏感性，与 MC 选择性相结合，可以允许对半乳糖血症的三种生物标志物进行快速和同时检测，这意味着仅通过一次分析即可快速诊断任何类型的半乳糖血症。电合成的 CuNWs 具有明确的形状，平均长度为 6 μm，宽度为 300 nm。修饰后的电极表现出两倍于非修饰电极的增强的电活性表面积。非常好的电极内重复性，相对标准偏差（RSD）<8%（n = 10），电极间重现性，RSD <12%（n = 5），表明纳米级电化学探测器具有极好的稳定性。在最佳化学条件（3 mM NaOH，pH 11.5）、电动条件（分离电压+750 V，注入+1500 V 持续 5 s）和电化学条件（在 3 mM NaOH，pH 11.5 中 E = +0.70 V）下，使用选定的珍贵未经诊断的新生儿尿液样本，明确鉴定了半乳糖血症疾病，区分了 I 型、II 型和 III 型。检测在不到 350 s 内完成，需要的尿液样本量可忽略不计，并且显示出令人印象深刻的信噪比特征（范围为 14 至 80）和亚毫摩尔检测限（LOD），远低于截止值（Gal 1-P > 0.4 mM 和 Gal > 1.4 mM）。还实现了出色的可重复回收率（93%-107%，RSD <6%），证明了该方法的可靠性。所研究的新生儿尿液样本的重要性证实了 MC-CuNWs 方法的分析能力，增强了微芯片技术的成熟度，并为未来在该领域实施筛选应用开辟了新途径。
