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Dual Amplification Fluorescence Assay for Alpha Fetal Protein Utilizing Immunohybridization Chain Reaction and Metal-Enhanced Fluorescence of Carbon Nanodots
journal contribution
posted on 2017-10-10, 00:00 authored by Dang-Dang Xu, Cui Liu, Cheng-Yu Li, Chong-Yang Song, Ya-Feng Kang, Chu-Bo Qi, Yi Lin, Dai-Wen Pang, Hong-Wu TangAs
an emerging fascinating fluorescent nanomaterial, carbon nanodots
(CDs) have attracted much attention owing of their unique properties
such as small size, antiphotobleaching, and biocompatibility. However,
its use in biomedical analysis is limited because of its low quantum
yield. Herein, we constructed a dual amplification fluorescence sensor
by incorporating immunohybridization chain reaction (immuno-HCR) and
metal-enhanced fluorescence (MEF) of CDs for the detection of alpha
fetal protein (AFP). The immunoplasmonic slide and detection antibodies-conjugated
oligonucleotide initiator are served to capture and probe AFP molecules,
respectively. Then, CD-tagged hairpin nucleic acids were introduced
to trigger the HCR, in which the hairpin nucleic acid and oligonucleotide
initiator are complementary. The interaction between CDs and the gold
nanoisland film greatly improves the radiative decay rate, increases
the quantum yield, and enhances the fluorescence emission of the CDs.
Furthermore, the HCR provides secondary amplification of fluorescence
intensity. Therefore, the MEF-capable immunohybridization reactions
provide obvious advantages and result in exceptional sensitivity.
In addition, the sandwich immunoassay method offers high specificity.
The results show a wide linearity between the fluorescence intensity
and AFP concentration over 5 orders of magnitude (0.0005–5
ng/mL), and the detection limit reaches as low as 94.3 fg/mL. This
method offers advantages of high sensitivity and reliability, wide
detection range, and versatile plasmonic chips, thus presenting an
alternative for the technologies in biomedical analysis and clinical
applications.
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hairpinfluorescence intensityamplification fluorescence sensorsensitivityquantumacidradiative decay rateHCRprobe AFP moleculesimmunohybridization chain reactionMEF-capable immunohybridization reactionssandwich immunoassay methodAlpha Fetal Protein Utilizing Immunohybridization Chain Reactiondetection antibodies-conjugated oligonucleotide initiatorgold nanoisland filmDual Amplification Fluorescence Assayanalysis
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