Poor fluorescence recovery at low analyte dosages and slow ligand binding kinetics are critical challenges currently limiting the use of aptamer-functionalized hydrogels for sensing small molecules. In this paper, we report an adenosine-responsive hydrogel sensor that integrates FRET-signaling aptamer switches into in situ-gelling thin-film hydrogels. The hydrogel sensor is able to entrap a high proportion of the sensing probes (>70% following vigorous washing), delay nucleolytic degradation, stabilize weak aptamer complexes to improve hybridization affinity and suppress fluorescence background, and provide high sensitivity in biological fluids (i.e., undiluted human serum). Furthermore, the developed hydrogel sensors were able to achieve low limits of detection (5.3 μM in buffer and 8.8 μM in serum) within 4 min of exposure to the sample, with signal generation requiring only 20 μL/well of analyte sample. The physical nature of the aptamer encapsulation allows this approach to accommodate virtually any small-molecule aptamer, avoiding the need for covalent anchoring and the complex modification of nucleic acid sequences typically required for effective aptamer-based molecular recognition.

中文翻译：

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基于适体的水凝胶传感平台能够使用低样品量对小分子进行低微摩尔检测

低分析物剂量下较差的荧光恢复和缓慢的配体结合动力学是目前限制适配体功能化水凝胶用于感测小分子的关键挑战。在本文中，我们报道了一种腺苷响应水凝胶传感器，它将 FRET 信号适体开关集成到原位凝胶薄膜水凝胶中。水凝胶传感器能够捕获高比例的传感探针（剧烈洗涤后>70%），延迟溶核降解，稳定弱适体复合物以提高杂交亲和力并抑制荧光背景，并在生物液体中提供高灵敏度（即，未稀释的人血清）。此外，所开发的水凝胶传感器能够在暴露于样品的 4 分钟内实现低检测限（缓冲液中为 5.3 μM，血清中为 8.8 μM），并且仅需要 20 μL/孔的分析物样品即可产生信号。适体封装的物理性质允许这种方法几乎容纳任何小分子适体，避免了共价锚定的需要以及有效基于适体的分子识别通常所需的核酸序列的复杂修饰。