Department of Electrical and Computer Engineering and ‡Department of Biomedical Engineering, University of California-Davis , Davis, California 95616, United States.
ACS Appl Mater Interfaces. 2017 Apr 19;9(15):12959-12966. doi: 10.1021/acsami.6b15212. Epub 2017 Jan 31.
Nanoporous gold (np-Au) electrode coatings significantly enhance the performance of electrochemical nucleic acid biosensors because of their three-dimensional nanoscale network, high electrical conductivity, facile surface functionalization, and biocompatibility. Contrary to planar electrodes, the np-Au electrodes also exhibit sensitive detection in the presence of common biofouling media due to their porous structure. However, the pore size of the nanomatrix plays a critical role in dictating the extent of biomolecular capture and transport. Small pores perform better in the case of target detection in complex samples by filtering out the large nonspecific proteins. On the other hand, larger pores increase the accessibility of target nucleic acids in the nanoporous structure, enhancing the detection limits of the sensor at the expense of more interference from biofouling molecules. Here, we report a microfabricated np-Au multiple electrode array that displays a range of electrode morphologies on the same chip for identifying feature sizes that reduce the nonspecific adsorption of proteins but facilitate the permeation of target DNA molecules into the pores. We demonstrate the utility of the electrode morphology library in studying DNA functionalization and target detection in complex biological media with a special emphasis on revealing ranges of electrode morphologies that mutually enhance the limit of detection and biofouling resilience. We expect this technique to assist in the development of high-performance biosensors for point-of-care diagnostics and facilitate studies on the electrode structure-property relationships in potential applications ranging from neural electrodes to catalysts.
纳米多孔金（np-Au）电极涂层由于其三维纳米级网络、高导电性、易于表面功能化和生物相容性，极大地提高了电化学核酸生物传感器的性能。与平面电极不同，由于其多孔结构，np-Au 电极在存在常见生物污垢介质的情况下也表现出灵敏的检测。然而，纳米基质的孔径在决定生物分子捕获和传输的程度方面起着关键作用。小孔在复杂样品中的目标检测中表现更好，因为它们可以过滤掉大的非特异性蛋白质。另一方面，较大的孔增加了纳米多孔结构中靶核酸的可及性，从而提高了传感器的检测限，但同时也增加了生物污垢分子的干扰。在这里，我们报告了一种微制造的 np-Au 多电极阵列，该阵列在同一芯片上显示出一系列电极形态，用于确定可减小蛋白质非特异性吸附但有利于靶 DNA 分子进入孔的特征尺寸。我们展示了电极形态文库在研究复杂生物介质中的 DNA 功能化和靶检测中的应用，特别强调了揭示相互增强检测限和抗生物污垢能力的电极形态范围。我们期望该技术有助于开发用于即时诊断的高性能生物传感器，并促进从神经电极到催化剂等潜在应用中电极结构-性能关系的研究。
