In vitro diagnostic technologies, used to evaluate disease status at the point-of-care (POC), are of urgent importance to improve diagnostic capabilities in bladder cancer. However, currently available approaches have a limitation because of their lack of detection for early-staged cancer. Herein, we developed an electrochemical immunosensor for the POC diagnosis of bladder cancer in which the enzyme alkaline phosphatase (ALP) and its metabolite, ascorbic acid 2-phosphate (AAP), are employed as the electrochemical label and redox signaling unit. The indium tin oxide (ITO) electrode exhibits no redox activity toward the AAP substrate, whereas its metabolic add of ascorbic acid (AA) produces strong oxidation current under the voltammetric measurement. The ITO electrode and the ALP enzyme are revealed as an excellent combination for the development of the electrochemical immunosensors in both direct- and sandwich-type immunoassay approach. Determination of apolipoprotein-A4 and metallopeptidase-9, two representative bladder cancer markers, were used to evaluate our approach, and excellent quantification with standard deviation 10 % was achieved. Overall, our results showed that our method offers an opportunity for the development of a variety of new forms of portable POC diagnostic devices with low cost and excellent performance.

中文翻译：

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基于氧化铟锡对碱性磷酸酶活性的电化学免疫分析

体外用于评估即时诊断（POC）疾病状况的诊断技术对于提高膀胱癌的诊断能力至关重要。但是，由于缺乏对早期癌症的检测，目前可用的方法存在局限性。在这里，我们开发了一种用于POC诊断膀胱癌的电化学免疫传感器，其中碱性磷酸酶（ALP）及其代谢产物抗坏血酸2-磷酸（AAP）被用作电化学标记和氧化还原信号单元。铟锡氧化物（ITO）电极对AAP基材没有氧化还原活性，而其抗坏血酸（AA）的代谢添加在伏安法测量下产生强氧化电流。ITO电极和ALP酶是直接和三明治型免疫测定方法中电化学免疫传感器开发的极佳组合。载脂蛋白A4和金属肽酶9的测定是两个代表性的膀胱癌标志物，用于评估我们的方法，并且以10％的标准差实现了出色的定量。总体而言，我们的结果表明，我们的方法为开发各种低成本，高性能的新型便携式POC诊断设备提供了机会。并实现了标准偏差10％的出色定量。总体而言，我们的结果表明，我们的方法为开发各种低成本，高性能的新型便携式POC诊断设备提供了机会。并实现了标准偏差10％的出色定量。总体而言，我们的结果表明，我们的方法为开发各种低成本，高性能的新型便携式POC诊断设备提供了机会。