The abuse of 17β-estradiol(E2) has aroused wide concern in environmental and biomedical fields, which severely affects the endocrine function of human and animals. Therefore, an ultrasensitive and accurate assay of E2 is critically important. Traditional chromatography or immunoassay techniques exhibited good sensitivity and selectivity, but expensive instruments and antibodies may pose cost and stability issues, as well as difficulties in meeting on-site detection requirements. Ultrasensitive, reliable, and on-site detection of E2 at trace level remains a challenge. Hence, developing a simple, ultrasensitive assay to simultaneously achieve accurate detection and rapid visual analysis of E2 is extremely crucial. We developed a versatile dual-mode photoelectrochemical (PEC) and colorimetric biosensor based on isothermal nucleic acid amplification strategy for the ultrasensitive and accurate detection of E2. The method modified titanium dioxide (TiO) with tungsten selenide (WSe) nanoflowers to synthesize WSe/TiO heterostructures as a substrate for signal amplification and nanoprobe modification. Isothermal nucleic acid amplification strategy has been proven to be a powerful tool for strong signal amplification. The presence of a target triggered the nucleic acid amplification reaction, and produced a large amount of tDNA that competed with G-quadruplex immobilized on the electrode surface. The remaining G-quadruplex/hemin catalyzed the 4-chloro-1-naphthol (4-CN) to form biocatalytic precipitation (BCP) and ABTS-HO chromogenic reaction, thus, the dual-mode platform was capable of achieving PEC-colorimetric ultrasensitive detection based on the catalytic activity of G-quadruplex/hemin DNAzyme. Within optimal conditions, the dual-mode biosensor exhibited a remarkable detection limit as low as 0.026 pM. Benefiting from the superior performance of WSe/TiO and the power signal amplification of isothermal nucleic acid amplification strategy, this aptasensor achieved the ultrasensitive detection of E2. The independent transmission paths of photoelectrochemical and colorimetric provide mutual support and flexible switching, significantly enhancing the overall sensitivity and accuracy of the detection strategy, which can meet the needs for E2 precise quantification and rapid on-site detection.

中文翻译：

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用于 17β-雌二醇测定的超灵敏双模式阶段：基于 WSe2/TiO2 修饰电极与核酸扩增相结合的光电化学和比色生物传感器


17β-雌二醇（E2）的滥用已引起环境和生物医学领域的广泛关注，严重影响人类和动物的内分泌功能。因此，超灵敏且准确的 E2 测定至关重要。传统的层析或免疫分析技术表现出良好的灵敏度和选择性，但昂贵的仪器和抗体可能会带来成本和稳定性问题，以及难以满足现场检测要求。对痕量 E2 进行超灵敏、可靠的现场检测仍然是一个挑战。因此，开发一种简单、超灵敏的检测方法以同时实现 E2 的准确检测和快速可视化分析至关重要。我们开发了一种基于等温核酸扩增策略的多功能双模式光电化学 (PEC) 和比色生物传感器，用于超灵敏且准确地检测 E2。该方法用硒化钨（WSe）纳米花修饰二氧化钛（TiO），合成WSe/TiO异质结构，作为信号放大和纳米探针修饰的基底。等温核酸扩增策略已被证明是强信号放大的有力工具。靶标的存在引发核酸扩增反应，并产生大量的tDNA，与固定在电极表面的G-四链体竞争。剩余的G-四联体/氯化血红素催化4-氯-1-萘酚（4-CN）形成生物催化沉淀（BCP）和ABTS-HO显色反应，因此，双模式平台能够实现PEC比色超灵敏基于G-四联体/血红素DNAzyme 催化活性的检测。 在最佳条件下，双模式生物传感器表现出低至 0.026 pM 的显着检测限。得益于WSe/TiO的优越性能和等温核酸扩增策略的功率信号放大，该适配体传感器实现了E2的超灵敏检测。光电化学和比色法独立的传输路径相互支持、灵活切换，显着提升检测策略的整体灵敏度和准确性，可满足E2精确定量和快速现场检测的需求。