Fabrication of nanoscale structures with localized surface plasmons allows for substantial increase in sensitivity of chem/bio sensors. The main challenge for realizing complex nanoplasmonic structures in solution is the high level of precision required at the nanoscale to position metal nanoparticles in 3D. In this study, we report a virus-like particle (VLP) for building a 3D plasmonic nanostructure in solution in which gold nanoparticles are precisely positioned on the VLP by directed self-assembly techniques. These structures allow for concentration of electromagnetic fields in the desired locations between the gold nanoparticles or “hot spots”. We measure the efficiency of the optical field spatial concentration for the first time, which results in a ten-fold enhancement of the capsid Raman peaks. Our experimental results agree with our 3D finite element simulations. Furthermore, we demonstrate as a proof-of-principle that the plasmonic nanostructures can be utilized in DNA detection down to 0.25ng/μl (lowest concentration tested), while the protein peaks from the interior of the nanoplasmonic structures, potentially, can serve as an internal tracer for the biosensors.

中文翻译：

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基于病毒的纳米等离子体结构作为表面增强拉曼生物传感器

具有局部表面等离子体激元的纳米级结构的制造可大大提高化学/生物传感器的灵敏度。在溶液中实现复杂的纳米等离子体结构的主要挑战是在纳米级以3D定位金属纳米颗粒所需的高精度。在这项研究中，我们报告了一种病毒样颗粒（VLP），用于在溶液中构建3D等离子体纳米结构，其中金纳米颗粒通过定向自组装技术精确定位在VLP上。这些结构允许将电磁场集中在金纳米颗粒或“热点”之间的所需位置。我们首次测量了光场空间集中的效率，这导致衣壳拉曼峰增强了十倍。我们的实验结果与我们的3D有限元模拟相吻合。此外，作为原理的证明，等离子纳米结构可用于低至0.25ng /μl（测试的最低浓度）的DNA检测中，而从纳米等离子结构内部的蛋白质峰可能可以用作用于生物传感器的内部示踪剂。