Implementing large arrays of gold nanowires as functional elements of a plasmonic biosensor is an important task for future medical diagnostic applications. Here we present a microfluidic-channel-integrated sensor for the label-free detection of biomolecules, relying on localized surface plasmon resonances. Large arrays (∼1 cm²) of vertically aligned and densely packed gold nanorods to receive, locally confine, and amplify the external optical signal are used to allow for reliable biosensing. We accomplish this by monitoring the change of the optical nanostructure resonance in the presence of biomolecules within the tight focus area above the nanoantennas, combined with a surface treatment of the nanowires for a specific binding of the target molecules. As a first application, we detect the binding kinetics of two distinct DNA strands as well as the following hybridization of two complementary strands (cDNA) with different lengths (25 and 100 bp). Upon immobilization, a redshift of 1 nm was detected; further backfilling and hybridization led to a peak shift of additional 2 and 5 nm for 25 and 100 bp, respectively. We believe that this work gives deeper insight into the functional understanding and technical implementation of a large array of gold nanowires for future medical applications.

中文翻译：

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基于金纳米天线垂直阵列的等离子生物传感器

实现大阵列的金纳米线作为等离子生物传感器的功能元件，对于未来的医学诊断应用而言是一项重要的任务。在这里，我们介绍了一种微流体通道集成的传感器，用于依靠局部表面等离振子共振的生物分子的无标记检测。大阵列（〜1 cm ²垂直排列并密集堆积的金纳米棒）（用于接收，局部限制和放大外部光信号）用于实现可靠的生物传感。我们通过在纳米天线上方紧密聚焦区域内存在生物分子的情况下监测光学纳米结构共振的变化，并结合纳米线的表面处理以实现目标分子的特异性结合，来实现这一目标。作为第一个应用程序，我们检测两条截然不同的DNA链的结合动力学，以及随后两条具有不同长度（25和100 bp）的互补链（cDNA）的杂交。固定后，检测到1 nm的红移。进一步的回填和杂交导致25 bp和100 bp的峰移分别增加了2 nm和5 nm。