Moving to ultra-low (<100 nL) sample volumes presents numerous challenges, many of which can be resolved by implementation of open nanofluidic films. These nanofluidic films are fabricated using a hexagonal network of gold-coated open microchannels which capture all of the following innovative advantages: (1) sample volumes of <100 nL cm⁻²; (2) zero analyte exchange and loss with the film materials; (3) rapid and omni-directional wicking transport of >500 nL min⁻¹ per square of film; (4) ultra-simple roll-to-roll fabrication; (5) stable and bio-compatible super-hydrophilicity for weeks in air by peptide surface modification. Validation includes both detailed in vitro characterization and in vivo validation with sweat transport from the human skin. Sampling times (skin-to-sensor) of <3 min were achieved, setting new benchmarks for the field of wearable sweat sensing. This work addresses significant challenges for sweat biosensing, or for any other nano-liter regime (<100 nL) fluid sampling and sensing application.

中文翻译：

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开放的纳米流体薄膜，具有快速运输且无需交换分析物的超低样品量†

移至超低（<100 nL）的样品量面临许多挑战，其中许多挑战可以通过实施开放式纳米流体薄膜来解决。这些纳米流体薄膜是使用六边形的镀金开放式微通道网络制成的，这些通道捕获了以下所有创新优势：（1）样品体积<100 nL cm ^-2；（2）与薄膜材料的分析物交换和损失为零；（3）每平方薄膜面积大于500 nL min ^-1的快速全向芯吸传输；（4）超简单的卷对卷制造；（5）通过肽表面修饰在空气中稳定且生物相容的超亲水性持续数周。验证包括详细的体外表征和体内通过人类皮肤的汗水传输进行验证。采样时间（从皮肤到传感器）小于3分钟，为可穿戴汗液传感领域树立了新的标杆。这项工作解决了汗液生物传感或任何其他纳升级（<100 nL）流体采样和传感应用的重大挑战。