Plasmonic Enhancement of Molecular Fluorescence near Silver Nanoparticles: Theory, Modeling, and Experiment
Plasmonic Enhancement of Molecular Fluorescence near Silver Nanoparticles: Theory, Modeling, and Experiment
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DOI：
10.1021/jp301598w
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发表时间：
2012-05-17
影响因子：
3.7
通讯作者：
Gaponenko, Sergey V.
中科院分区：
文献类型：
--
作者：
Guzatov, Dmitry V.;Vaschenko, Svetlana V.;Gaponenko, Sergey V.
等离子体纳米结构中分子探针的金属增强荧光提供了高灵敏度的化学和生物医学分析，但对这种现象的综合理论还远远没有完成。在本研究中，对银球形纳米颗粒附近荧光团的整体发光增强/猝灭进行了系统的理论分析。该方法考虑了局部强度增强、辐射和非辐射速率变化、光偏振、分子位置及其偶极矩取向。已经对广泛用于生物医学研究和开发的基于荧光素的标签（例如Alexa Fluor 488）进行了数值模拟。当纳米颗粒直径为50 nm时，最佳激发波长为370 nm，增强效果达到50倍以上。对于长波激发，更大的粒子效率更高。用异硫氰酸荧光素偶联牛血清白蛋白的实验证实了理论预测。结果提供了一个广泛和有希望的估计，简单和负担得起的银基纳米结构用于荧光等离子体传感器。
Metal-enhanced fluorescence of molecular probes in plasmonic nanostructures offers highly sensitive chemical and biomedical analyses, but a comprehensive theory of the phenomenon is far from being complete. In this study, a systematic theoretical analysis is provided for overall luminescence enhancement/quenching for fluorophores near silver spherical nanoparticles. The approach accounts for local intensity enhancement, radiative and nonradiative rates modification, light polarization, molecule position, and its dipole moment orientation. Numerical modeling has been performed for fluorescein-based labels (e.g., Alexa Fluor 488) widely used in biomedical studies and development. The maximal enhancement exceeding 50 times is predicted for nanoparticle diameter 50 nm, the optimal excitation wavelength being 370 nm. For long-wave excitation, bigger particles are more efficient. The experiments with a fluorescein isothiocyanate conjugate of bovine serum albumin confirmed theoretical predictions. The results provide an extensive and promising estimate for simple and affordable silver-based nanostructures to be used in fluorescent plasmonic sensors.