Developing ultrasensitive chemical sensors with small scale and fast response through simple design and low‐cost fabrication is highly desired but still challenging. Herein, a simple and universal sensing platform based on a hydrogel interferometer with femtomol‐level sensitivity in detecting (bio)chemical molecules is demonstrated. A unique local concentrating effect (up to 10⁹ folds) in the hydrogel induced by the strong analyte binding and large amount of ligands, combined with the signal amplification effect by optical interference, endows this platform with an ultrahigh sensitivity, specifically 10⁻¹⁴m for copper ions and 1.0 × 10⁻¹¹ mg mL⁻¹ for glycoprotein with 2–4 order‐of‐magnitude enhancement. The specific chemical reactions between selected ligands and target analytes provide high selectivity in detecting complex fluids. This universal principle with broad chemistry, simple physics, and modular design allows for high performance in detecting wide customer choices of analytes, including metal ions and proteins. The scale of the sensor can be down to micrometer size. The nature of the soft gel makes this platform transparent, flexible, stretchable, and compatible with a variety of substrates, showing high sensing stability and robustness after 200 cycles of bending or stretching. The outstanding sensing performance grants this platform great promise in broad practical applications.

中文翻译：

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水凝胶干涉法用于超灵敏和高度选择性的化学检测

迫切需要通过简单的设计和低成本的制造来开发具有小规模和快速响应的超灵敏化学传感器，但仍具有挑战性。本文展示了一种基于水凝胶干涉仪的简单通用传感平台，该传感器具有飞摩尔级的灵敏度，可以检测（生物）化学分子。强大的分析物结合和大量配体在水凝胶中引起的独特的局部浓缩作用（高达10 ⁹倍），再加上光学干扰产生的信号放大作用，使该平台具有超高的灵敏度，特别是10 ^-14 m用于铜离子和1.0×10 ^-11 mg mL ^-1用于糖蛋白，幅度提高了2到4个数量级。所选配体与目标分析物之间的特定化学反应在检测复杂流体中提供了高选择性。这种具有广泛的化学原理，简单的物理原理和模块化设计的通用原理，可在检测广泛的客户选择的分析物（包括金属离子和蛋白质）时提供高性能。传感器的规模可以缩小到微米大小。软凝胶的性质使该平台透明，灵活，可拉伸，并与多种基材兼容，在200次弯曲或拉伸循环后显示出很高的感测稳定性和鲁棒性。出色的传感性能使该平台在广泛的实际应用中具有广阔的前景。