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Updated: Feb 14, 2026

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis
Published on: March 7, 2018
Signal-amplifying nanoparticle/hydrogel hybrid microarray biosensor for metal-enhanced fluorescence detection of
Minsu Kim1, Ji Eon Kwon2, Kangwon Lee3
1Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
Abstract:
In this study, we developed an enzyme-based miniaturized fluorescence biosensor to detect paraoxon, one of the most well-known neurotoxic organophosphorus compounds. The biosensor was fabricated with poly(ethylene glycol) (PEG) hydrogel microarrays that entrapped acetylcholinesterase (AChE) and quantum dots (QDs) as fluorescence reporters. Metal-enhanced fluorescence (MEF) was utilized to amplify the fluorescence signal, which was achieved by decorating QDs on the surface of silica-coated silver nanoparticles (Ag@Silica). The MEF effects of Ag@Silica were optimized by tuning the thickness of the silica shells, and under the optimized conditions, the fluorescence intensity was shown to be increased 5 fold, compared with the system without MEF. PEG hydrogel microarray entrapping QD-decorated Ag@Silica and AChE was prepared via photopatterning process. The entrapped AChE hydrolyzed paraoxon to produce p-nitrophenol within the hydrogel microstructure, which subsequently quenched the fluorescence of the QDs on the surface of Ag@Silica. The MEF-assisted fluorescence detection resulted in a significant enhancement of paraoxon detection. The detection limit was approximately 1.0 × 10-10 M and 2.0 × 10-7 M for sensing with and without MEF, respectively. The successful integration of a hydrogel microarray system with a microfluidic system was demonstrated to be a potential application for the MEF-based micro-total-analysis-system.
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