Galectin-1 protein has been recently recognized as a valuable urinary biomarker for the diagnosis and prognosis of bladder cancer. Herein, we present a sensitive and specific impedimetric immunosensor for the quantitative and label free detection of Galectin-1 protein in clinical urine samples. The immunosensor consists of nine gold interdigitated microelectrodes (3 × 3 array), which can simultaneously monitor multiple immunoreactions by analyzing the normalized impedance variations at each microelectrode during immunosensing. To obtain enhanced sensitivities, we have utilized Galectin-1/Al₂O₃ nanoprobes (Galectin-1 antibody conjugated to alumina nanoparticles) that can be selectively trapped on the microelectrode surface using positive dielectrophoresis (p-DEP). Preliminary studies highlight the feasibility of the proposed immunosensor for Gal −1 detection in T24 cell lysate spiked phosphate buffer saline and artificial urine samples with a limit of detection that is estimated to be in the pg/ml range. To verify its practical feasibility, we have tested the immunosensor for Galectin-1 detection in clinical urine samples obtained from normal patients and those diagnosed with bladder cancer. Analysis of the clinical tests shows that the median normalized impedance variation during immunosensing for 22 cancer patients and 26 normal patients is 27% and 10%, respectively, with an identified cutoff point of 19.5% above which the sensitivity and specificity of bladder cancer detection was 82.1% and 80.8%, respectively. Based on these results, the proposed immunosensor shows promise for bladder cancer diagnosis and prognosis in a point of care format, thus enabling improved public health monitoring.

中文翻译：

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无标记的阻抗式免疫传感器可有效检测临床尿液样本中的膀胱癌。

最近已经认识到Galectin-1蛋白是用于膀胱癌诊断和预后的有价值的尿液生物标志物。在本文中，我们提出了一种灵敏且特异的阻抗免疫传感器，用于定量和无标签检测临床尿液样本中的Galectin-1蛋白。免疫传感器由九个金指状微电极（3×3阵列）组成，可通过分析免疫传感期间每个微电极上的标准化阻抗变化来同时监视多个免疫反应。为了获得更高的灵敏度，我们利用了Galectin-1 / Al ₂ O ₃可以使用正介电电泳（p-DEP）选择性地捕获在微电极表面的纳米探针（与氧化铝纳米颗粒偶联的Galectin-1抗体）。初步研究突出了建议的免疫传感器在T24细胞裂解液加标磷酸盐缓冲液和人工尿液样品中进行Gal -1检测的可行性，其检测极限估计在pg / ml范围内。为了验证其实际可行性，我们已经对从正常患者和诊断为膀胱癌的临床尿液样本中检测Galectin-1的免疫传感器进行了测试。临床测试分析显示，在22例癌症患者和26例正常患者的免疫传感过程中，标准化阻抗中位数变化分别为27％和10％，确定的临界点为19。高于5％时，膀胱癌检测的敏感性和特异性分别为82.1％和80.8％。基于这些结果，所提出的免疫传感器显示出以护理点形式进行膀胱癌诊断和预后的希望，从而可以改善公共健康监测。