Single nanochannels show unique transport properties due to nanoconfinement. It has been demonstrated that at submillimolar concentrations of divalent cations, a nanoprecipitation reaction can occur in nanochannels. Although several reports have shown, described, and modeled the nanoprecipitation process, no further advantages have been taken from this phenomenon. Here, we show that the nanoprecipitation reaction can be incorporated into enzyme-modified nanochannels to enhance the performance of small-molecule biosensors via in situ amplification reactions. Contrary to the working principle of previous enzymatic nanofluidic biosensors, the nanofluidic biosensor described in this work operates on the basis of concerted functions: pH-shifting enzymatic activity and nanoprecipitation. We show that the simple addition of Ca²⁺ and Mg²⁺ ions in the working analyte solution containing urea can lower the detection limit from the nanometer to the subnanometer regime and modulate the dynamic linear range. This approach enables the implementation of more sensitive real-time nanofluidic detection methods without increasing the complexity of the nanofluidic platform or the sensing approach. We envision that the integration of concerted functions in nanofluidic architectures will play a key role in expanding the use of these nanoscale devices for analytical purposes.

中文翻译：

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纳米沉淀增强酶纳米流体生物传感器的灵敏度

由于纳米限制，单个纳米通道表现出独特的传输特性。已经证明，在二价阳离子的亚毫摩尔浓度下，纳米沉淀反应可以在纳米通道中发生。尽管一些报告已经展示、描述和模拟了纳米沉淀过程，但尚未从这种现象中获得进一步的优势。在这里，我们证明纳米沉淀反应可以纳入酶修饰的纳米通道中，通过原位放大反应增强小分子生物传感器的性能。与以前的酶纳米流体生物传感器的工作原理相反，本工作中描述的纳米流体生物传感器基于协同功能进行操作：pH 变化酶活性和纳米沉淀。我们表明，在含有尿素的工作分析物溶液中简单添加Ca ²⁺和Mg ²⁺离子可以将检测限从纳米降低到亚纳米范围，并调节动态线性范围。这种方法能够实现更灵敏的实时纳米流体检测方法，而不会增加纳米流体平台或传感方法的复杂性。我们预计，纳米流体结构中协同功能的集成将在扩大这些纳米级设备用于分析目的的用途方面发挥关键作用。