Sadeghi Seyed M, Gutha Rithvik R, Wing Waylin J, Sharp Christina, Capps Lucas, Mao Chuanbin
Department of Physics, University of Alabama in Huntsville, Huntsville, Alabama, 35899, USA.
Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma 73019, USA.
J Phys D Appl Phys. 2017;50(14). doi: 10.1088/1361-6463/aa605e. Epub 2017 Mar 9.
We study biological sensing using plasmonic and photonic-plasmonic resonances of arrays of ultralong metallic nanorods and analyze the impact of these resonances on emission dynamics of quantum dot bioconjugates. We demonstrate that the LSPRs and plasmonic lattice modes of such array can be used to detect a single self-assembled monolayer of alkanethiol at the visible (550 nm) and near infrared (770 nm) range with well resolved shifts. We study adsorption of streptavidin-quantum dot conjugates to this monolayer, demonstrating that formation of nearly two dimensional arrays of quantum dots with limited emission blinking can lead to extra well-defined wavelength shifts in these modes. Using spectrally-resolved lifetime measurements we study the emission dynamics of such quantum dot bioconjugates within their monodispersed size distribution. We show that, despite their close vicinity to the nanorods, the rate of energy transfer from these quantum dots to nanorods is rather weak, while the plasmon field enhancement can be strong. Our results reveal that the nanorods present a strongly wavelength or size-dependent non-radiative decay channel to the quantum dot bioconjugates.
我们利用超长金属纳米棒阵列的等离子体和光子-等离子体共振来研究生物传感，并分析这些共振对量子点生物共轭物发射动力学的影响。我们证明，这种阵列的局域表面等离子体共振（LSPRs）和等离子体晶格模式可用于在可见光（550纳米）和近红外（770纳米）范围内检测单层自组装烷硫醇，且位移分辨良好。我们研究了链霉亲和素-量子点共轭物在该单层上的吸附，表明形成具有有限发射闪烁的近二维量子点阵列可导致这些模式中额外的明确定义的波长位移。通过光谱分辨寿命测量，我们研究了这种量子点生物共轭物在其单分散尺寸分布内的发射动力学。我们表明，尽管这些量子点与纳米棒非常接近，但从这些量子点到纳米棒的能量转移速率相当弱，而等离子体场增强可能很强。我们的结果表明，纳米棒为量子点生物共轭物提供了一个强烈依赖波长或尺寸的非辐射衰变通道。
