Photoanode sensing platforms with remarkable photoelectrochemical (PEC) response and satisfying visible-light absorption have become the most promising detection systems. Nevertheless, their inevitable electrophilic character limits their expansion in the bioassay because of reductive substances in serum or other body fluids that can severely interfere with the photocurrent to be read. To solve it, a PEC platform-assembled dual-active electrode is designed to realize the separation of biological monitoring from the photoanode. The ferricyanide ([Fe(CN)₆]^3–)-mediated redox cycle is first proposed to meet the gain and loss electron requirements of the PEC system. It can avoid the self-reaction in the electrolyte caused by the addition of a traditional electron donor and acceptor, for instance, ascorbic acid and hydrogen peroxide. As a consequence, the traditional counter electrode (Pt wire) is replaced by Fe₂O₃/AgInS₂ heterojunction, which can amplify the PEC response of the cathode to meet the requirement of trace analysis. An aptasensor fabricated by the above strategies exhibits convincing data for 17β-estradiol (E2) detection from which a wide detection range is obtained in 10 fg/mL to 1 μg/mL with a detection limit of 2.74 fg/mL (S/N = 3). These advanced elements show a rosy prospect for environmental monitoring and point-of-care biomarker diagnosis.

中文翻译：

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从光电阳极分离生物事件：走向铁氰化物介导的集成光电阳极和光电阴极的氧化还原循环光电化学系统。

具有卓越的光电化学（PEC）响应和令人满意的可见光吸收能力的光阳极传感平台已成为最有前途的检测系统。然而，由于血清或其他体液中的还原性物质会严重干扰待读取的光电流，它们不可避免的亲电特性限制了其在生物测定中的扩展。为了解决这个问题，设计了一个PEC平台组装的双活性电极，以实现生物监测与光电阳极的分离。铁氰化物（[Fe（CN）₆ ] ^3–首先提出了介导的氧化还原循环，以满足PEC系统的增益和损耗电子要求。它可以避免由于添加传统的电子供体和受体（例如抗坏血酸和过氧化氢）而引起的电解质中的自反应。结果，用Fe ₂ O ₃ / AgInS ₂异质结代替了传统的对电极（铂丝），可以放大阴极的PEC响应，以满足痕量分析的要求。通过上述策略制造的适体传感器显示出令人信服的17β-雌二醇（E2）检测数据，从中可以得到10 fg / mL至1μg/ mL的宽检测范围，检测限为2.74 fg / mL（S / N= 3）。这些先进元素为环境监测和即时医疗标志物的诊断显示了美好的前景。