Huldin Grayson F, Huang Junming, Reitemeier Julius, Fu Kaiyu X
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Materials Science and Engineering Program, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Faraday Discuss. 2025 Feb 17;257(0):316-332. doi: 10.1039/d4fd00144c.
The transition to a personalized point-of-care model in medicine will fundamentally change the way medicine is practiced, leading to better patient care. Electrochemical biosensors based on structure-switching aptamers can contribute to this medical revolution due to the feasibility and convenience of selecting aptamers for specific targets. Recent studies have reported that nanostructured electrodes can enhance the signals of aptamer-based biosensors. However, miniaturized systems and body fluid environments pose challenges such as signal-to-noise ratio reduction and biofouling. To address these issues, researchers have proposed various electrode coating materials, including zwitterionic materials, biocompatible polymers and hybrid membranes. Nafion, a commonly used ion exchange membrane, is known for its excellent permselectivity and anti-biofouling properties, making it a suitable choice for biosensor systems. However, the performance and mechanism of Nafion-coated aptamer-based biosensor systems have not been thoroughly studied. In this work, we present a Nafion-coated gold nanoporous electrode, which excludes Nafion from the nanoporous structures and allows the aptamers immobilized inside the nanopores to freely detect chosen targets. The nanopore electrode is formed by a sputtering and dealloying process, resulting in a pore size in tens of nanometers. The biosensor is optimized by adjusting the electrochemical measurement parameters, aptamer density, Nafion thickness and nanopore size. Furthermore, we propose an explanation for the unusual signaling behavior of the aptamers confined within the nanoporous structures. This work provides a generalizable platform to investigate membrane-coated aptamer-based biosensors.
医学向个性化即时护理模式的转变将从根本上改变医学实践方式，从而带来更好的患者护理。基于结构转换适配体的电化学生物传感器，因其针对特定靶点选择适配体的可行性和便利性，能够推动这场医学革命。最近的研究报道，纳米结构电极可以增强基于适配体的生物传感器的信号。然而，小型化系统和体液环境带来了诸如信噪比降低和生物污染等挑战。为了解决这些问题，研究人员提出了各种电极涂层材料，包括两性离子材料、生物相容性聚合物和混合膜。Nafion是一种常用的离子交换膜，以其优异的选择透过性和抗生物污染性能而闻名，使其成为生物传感器系统的合适选择。然而，基于Nafion涂层的适配体生物传感器系统的性能和机制尚未得到充分研究。在这项工作中，我们展示了一种Nafion涂层的金纳米多孔电极，它将Nafion排除在纳米多孔结构之外，并使固定在纳米孔内的适配体能够自由检测选定的靶点。纳米孔电极通过溅射和脱合金工艺形成，孔径为几十纳米。通过调整电化学测量参数、适配体密度、Nafion厚度和纳米孔尺寸对生物传感器进行了优化。此外，我们对限制在纳米多孔结构内的适配体的异常信号行为提出了一种解释。这项工作为研究基于膜涂层适配体的生物传感器提供了一个可推广的平台。
