In this work, a multicolor visual immunoassay platform was developed. The photoelectric effects of Ag2S NPs@ZnO NTs made the color changes of PANI/PB, which enabled visual inspection of CEA. Under the visible light excitation, Ag2S NPs@ZnO NTs generates electron-holes. Where, photoelectrons will pass electrical circuit to PB and photoinduced holes will oxidize PANI, which making the PANI/PB composite changes from emerald green-blue-purple-black colors. When CEA was incubated, the migration rate of photogenerated carriers is slowed down owing to the steric hindrance, resulting in different color changes of PANI/PB. In addition, the average green channel of PANI/PB read by photoshop has a certain correlated linear relationship with the concentration of CEA. Meanwhile, we can observe the color transformation of PANI/PB with our own eyes. By integrating advantages of photoelectrochemistry and colorimetry, the linear range of CEA detection was 0.1-20 ng/mL, and the detection limit was 0.05 ng/mL (S/N = 3). More importantly, this multicolor sensing method is very convenient, simple and low-cost. The photocarriers-modulated colorimetric strategy also provides a novel idea for visual portable platform design in clinical diagnosis.

中文翻译：

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基于Ag2S NPs@ZnO NTs的CEA光电效应驱动PANI/PB多色可视化检测

在这项工作中，开发了一个多色视觉免疫分析平台。Ag2S NPs@ZnO NTs 的光电效应使 PANI/PB 的颜色发生变化，从而可以对 CEA 进行目视检查。在可见光激发下，Ag2S NPs@ZnO NTs 产生电子空穴。其中，光电子将通过电路到达 PB，光致空穴将氧化 PANI，使 PANI/PB 复合材料从翠绿色-蓝-紫-黑色变为绿色。当CEA孵育时，由于空间位阻，光生载流子的迁移速度减慢，导致PANI/PB的颜色发生不同的变化。此外，photoshop读取的PANI/PB平均绿色通道与CEA浓度存在一定的相关线性关系。同时，我们可以亲眼观察PANI/PB的颜色变化。综合光电化学和比色法的优点，CEA检测的线性范围为0.1-20 ng/mL，检出限为0.05 ng/mL（S/N=3）。更重要的是，这种多色传感方法非常方便、简单且成本低。光载流子调制比色策略也为临床诊断中的可视便携式平台设计提供了一种新思路。