We report on a highly sensitive, selective, and flexible enzymatic sensor based on Zinc oxide nanoflakes (ZnO NFs) for noninvasive L-lactate sensing in sweat. A single step sonochemical process was used to synthesize ZnO NFs on gold-coated flexible polyethylene terephthalate (PET) substrates. The lactate oxidase enzyme (LOx) immobilized on the as-synthesized ZnO-NFs-based sensing electrode provided a high level of selectivity for lactate sensing. The sensor was tested in the range of 10 pM–20 mM, which covers the entire physiological range and demonstrated the sensitivity of $11.76~\mu \text{A}$ /decade/cm2 and the limit of detection (LoD) of 1.26 nM. The presented sensor does not require a linker due to the high isoelectric point of ZnO-NFs yet demonstrated ~55 times better response compared to conventional gold electrodes with a linker. Our statistical analysis showed that the sensor also has high reproducibility.

中文翻译：

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基于氧化锌纳米薄片的灵活且无连接器的酶传感器，用于汗液中的无创 L-乳酸传感

我们报告了一种基于氧化锌纳米薄片 (ZnO NFs) 的高灵敏度、选择性和灵活的酶传感器，用于汗液中的无创 L-乳酸传感。使用单步声化学工艺在镀金的柔性聚对苯二甲酸乙二醇酯 (PET) 基材上合成 ZnO NF。固定在合成的 ZnO-NFs 传感电极上的乳酸氧化酶 (LOx) 为乳酸传感提供了高水平的选择性。该传感器在10 pM-20 mM的范围内进行了测试，覆盖了整个生理范围，并展示了$11.76~\mu \text{A}$ /decade/cm2的灵敏度和1.26 nM的检测限（LoD） . 由于 ZnO-NFs 的高等电点，所提出的传感器不需要连接器，但与带有连接器的传统金电极相比，其响应要好 55 倍。