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Proceedings Paper

Biosensing via light scattering from plasmonic core-shell nanospheres coated with DNA molecules
Author(s): Huai-Yi Xie; Minfeng Chen; Yia-Chung Chang; Rakesh Singh Moirangthem
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Paper Abstract

We present both experimental and theoretical studies for investigating DNA molecules attached on metallic nanospheres. We have developed an efficient and accurate numerical method to investigate light scattering from plasmonic nanospheres on a substrate covered by a shell, based on the Green’s function approach with suitable spherical harmonic basis. Next, we use this method to study optical scattering from DNA molecules attached to metallic nanoparticles placed on a substrate and compare with experimental results. We obtain fairly good agreement between theoretical predictions and the measured ellipsometric spectra. The metallic nanoparticles were used to detect the binding with DNA molecules in a microfluidic setup via spectroscopic ellipsometry (SE), and a detectable change in ellipsometric spectra was found when DNA molecules are captured on Au nanoparticles. Our theoretical simulation indicates that the coverage of Au nanosphere by a submonolayer of DNA molecules, which is modeled by a thin layer of dielectric material (which may absorb light), can lead to a small but detectable spectroscopic shift in both the Ψ and Δ spectra with more significant change in Δ spectra in agreement with experimental results. Our studies demonstrated the ultrasensitive capability of SE for sensing submonolayer coverage of DNA molecules on Au nanospheres. Hence the spectroscopic ellipsometric measurements coupled with theoretical analysis via an efficient computation method can be an effective tool for detecting DNA molecules attached on Au nanoparticles, thus achieving label-free, non-destructive, and high-sensitivity biosensing with nanoscale resolution.

Paper Details

Date Published: 16 May 2017
PDF: 7 pages
Proc. SPIE 10216, Smart Biomedical and Physiological Sensor Technology XIV, 1021602 (16 May 2017); doi: 10.1117/12.2266607
Show Author Affiliations
Huai-Yi Xie, Academia Sinica (Taiwan)
Minfeng Chen, Academia Sinica (Taiwan)
Yia-Chung Chang, Academia Sinica (Taiwan)
National Cheng Kung Univ. (Taiwan)
Rakesh Singh Moirangthem, Academia Sinica (Taiwan)
Indian School of Mines (India)

Published in SPIE Proceedings Vol. 10216:
Smart Biomedical and Physiological Sensor Technology XIV
Brian M. Cullum; Douglas Kiehl; Eric S. McLamore, Editor(s)

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