Abstract
DNA-assembled
nanoparticle superstructures offer numerous bioresponsive
properties that can be utilized for point-of-care diagnostics. Functional
DNA sequences such as deoxyribozymes (DNAzymes) provide novel bioresponsive
strategies and further extend the application of DNA-assembled nanoparticle
superstructures. In this work, we describe a microRNA detection biosensor
that combines magnetic nanoparticle (MNP) assemblies with DNAzyme-assisted
target recycling. The DNA scaffolds of the MNP assemblies contain
substrate sequences for DNAzyme and can form cleavage catalytic structures
in the presence of target DNA or RNA sequences, leading to rupture
of the scaffolds and disintegration of the MNP assemblies. The target
sequences are preserved during the cleavage reaction and release into
the suspension to trigger the digestion of multiple DNA scaffolds.
The high local concentration of substrate sequences in the MNP assemblies
reduces the diffusion time for target recycling. The concentration
of released MNPs, which is proportional to the concentration of the
target, can be quantified by a 405 nm laser-based optomagnetic sensor.
For the detection of let-7b in 10% serum, after 1 h of isothermal
reaction at 50 °C, we found a linear detection range between
10 pM and 100 nM with a limit of detection of 6 pM. For the quantification
of DNA target in buffer solution, a limit of detection of 1.5 pM was
achieved. Compared to protein enzyme-based microRNA detection methods,
the proposed DNAzyme-based biosensor has an increased stability, a
reduced cost and a possibility to be used in living cells, all of
which are valuable features for biosensing applications.
Original language | English |
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Journal | ACS Sensors |
Volume | 3 |
Issue number | 9 |
Pages (from-to) | 1884-1891 |
Number of pages | 8 |
ISSN | 2379-3694 |
DOIs | |
Publication status | Published - 2018 |
Bibliographical note
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.Keywords
- MicroRNA detection
- DNAzyme
- Magnetic nanoparticles
- DNA-assembled superstructures
- Optomagnetic bioassay