Feasibility of Using Bimetallic Plasmonic Nanostructures to Enhance the Intrinsic Emission of Biomolecules
Feasibility of Using Bimetallic Plasmonic Nanostructures to Enhance the Intrinsic Emission of Biomolecules
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DOI：
10.1021/jp205108s
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发表时间：
2011-09-01
影响因子：
3.7
通讯作者：
Ray, Krishanu
中科院分区：
文献类型：
--
作者：
Chowdhury, Mustafa H.;Chakraborty, Sudipto;Ray, Krishanu
检测蛋白质的内源荧光在生物测定中是重要的，因为它可以潜在地消除外部荧光团对蛋白质的标记。这是有利的，因为使用外部荧光标记来标记生物分子需要化学修饰和额外的孵育和洗涤步骤，这可能潜在地干扰生物分子的天然功能。因此，外部标记步骤增加了生物测定的费用和复杂性。在本文中，我们首次研究了使用由银（Ag）和铝（Al）制成的纳米结构来实现金属增强荧光（MEF）现象的可行性，用于增强生物分子在紫外（UV）光谱区域的本征发射。测定了色氨酸类似物N-乙酰基-L-色氨酸酰胺（NATA）和酪氨酸类似物N-乙酰基-L-酪氨酸酰胺（NATA-tyr）的荧光强度和寿命。与石英对照相比，在纳米结构的存在下记录了高达10倍的荧光强度增加和氨基酸寿命的同时减少。我们进行了一个模型蛋白质测定，涉及生物素化的牛血清白蛋白（bt-BSA）和链霉亲和素的pendulum纳米结构的基板上的MEF从pendulum纳米结构的程度上的距离依赖性的影响进行调查，发现一个最大的增强超过15倍的两层bt-BSA和链霉亲和素。我们还使用了时域有限差分（FDTD）计算来探索纳米结构如何与平面波和激发态荧光团在UV区域相互作用，并证明了纳米结构是一个有效的平台，用于增强蛋白质和其他生物分子的固有发射。
Detection of the intrinsic fluorescence from proteins is important in bioassays because it can potentially eliminate the labeling of external fluorophores to proteins. This is advantageous because using external fluorescent labels to tag biomolecules requires chemical modification and additional incubation and washing steps, which can potentially perturb the native functionality of the biomolecules. Hence the external labeling steps add expense and complexity to bioassays. In this paper, we investigate for the first time the feasibility of using bimetallic nanostructures made of silver (Ag) and aluminum (Al) to implement the metal-enhanced fluorescence (MEF) phenomenon for enhancing the intrinsic emission of biomolecules in the ultraviolet (UV) spectral region. Fluorescence intensities and lifetimes of a tryptophan analogue N-acetyl-L-tryptophanamide (NATA) and a tyrosine analogue N-acetyl-L-tyrosinamide (NATA-tyr) were measured. Increase in fluorescence intensities of up to 10-fold and concurrent decrease in lifetimes for the amino acids were recorded in the presence of the bimetallic nanostructures when compared to quartz controls. We performed a model protein assay involving biotinylated bovine serum albumin (bt-BSA) and streptavidin on the bimetallic nanostructured substrate to investigate the distance-dependent effects on the extent of MEF from the bimetallic nanostructures and found a maximum enhancement of over 15-fold for two layers of bt-BSA and streptavidin. We also used finite-difference time-domain (FDTD) calculations to explore how bimetallic nanostructures interact with plane waves and excited state fluorophores in the UV region and demonstrate that the bimetallic substrates are an effective platform for enhancing the intrinsic emission of proteins and other biomolecules.