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Silver coated magnetic nanoparticles for enhanced nucleic acid detection
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Paper Abstract

Nanoparticle-based fluorescence DNA/RNA sensing offers promising applications in both research and medical diagnosis due to the ease of surface chemical modification and sample handling, allowing detection in complex media. The performance of the conventional fluorescence biosensors is often limited by the insufficient fluorescence signal. To overcome the disadvantage, we advanced silver-coated magnetic nanoparticles with strong plasmon resonance to enhance the molecular beacon (MB)-based nucleic acid nanosensors. The silver-coated magnetic nanoparticles were chemically synthesized to compose of 20 nm iron oxide magnetic nanoparticle core and 60 nm thick Ag coating, forming iron oxide/Ag core-shell nanoparticles. Fluorescently labeled DNA MBs were immobilized on the Ag surface which serves as the quencher for the closed MBs and provides fluorescence enhancement for the unfolded MBs in the presence of the complementary target sequence. More importantly, the improved Ag shell mitigates the strong optical absorbance in the visible range associated with the magnetic nanoparticles increasing the fluorescence intensity. The detection was performed by dispersing the nanosensors in a 20 μl analyte solution for 10 minutes for accelerated target capture through 3D diffusion and concentrating them magnetically for enhanced fluorescence signal acquisition. The rapid, label-free DNA detection resulted in a detection limit of 10 pM target DNA.

Paper Details

Date Published: 9 September 2019
PDF: 5 pages
Proc. SPIE 11087, Biosensing and Nanomedicine XII, 110870Z (9 September 2019); doi: 10.1117/12.2529574
Show Author Affiliations
Ye Liu, Oregon State Univ. (United States)
Bo Wu, Oregon State Univ. (United States)
Yi-Chieh Wang, Oregon State Univ. (United States)
Ekembu K. Tanyi, Oregon State Univ. (United States)
Li-Jing Cheng, Oregon State Univ. (United States)


Published in SPIE Proceedings Vol. 11087:
Biosensing and Nanomedicine XII
Hooman Mohseni; Massoud H. Agahi, Editor(s)

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