Attomolar DNA detection with chiral nanorod assemblies
Open Access
- 28 October 2013
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Communications
- Vol. 4 (1), 2689
- https://doi.org/10.1038/ncomms3689
Abstract
Nanoscale plasmonic assemblies display exceptionally strong chiral optical activity. So far, their structural design was primarily driven by challenges related to metamaterials whose practical applications are remote. Here we demonstrate that gold nanorods assembled by the polymerase chain reaction into DNA-bridged chiral systems have promising analytical applications. The chiroplasmonic activity of side-by-side assembled patterns is attributed to a 7–9 degree twist between the nanorod axes. This results in a strong polarization rotation that matches theoretical expectations. The amplitude of the bisignate ‘wave’ in the circular dichroism spectra of side-by-side assemblies demonstrates excellent linearity with the amount of target DNA. The limit of detection for DNA using side-by-side assemblies is as low as 3.7 aM. This chiroplasmonic method may be particularly useful for biological analytes larger than 2–5 nm which are difficult to detect by methods based on plasmon coupling and ‘hot spots’. Circular polarization increases for inter-nanorod gaps between 2 and 20 nm when plasmonic coupling rapidly decreases. Reaching the attomolar limit of detection for simple and reliable bioanalysis of oligonucleotides may have a crucial role in DNA biomarker detection for early diagnostics of different diseases, forensics and environmental monitoring.This publication has 40 references indexed in Scilit:
- Chiral plasmonics of self-assembled nanorod dimersScientific Reports, 2013
- First enantioseparation and circular dichroism spectra of Au38 clusters protected by achiral ligandsNature Communications, 2012
- Side-by-Side Assembly of Gold Nanorods Reduces Ensemble-Averaged SERS IntensityThe Journal of Physical Chemistry C, 2012
- Gold Nanoparticles with Asymmetric Polymerase Chain Reaction for Colorimetric Detection of DNA SequenceAnalytical Chemistry, 2012
- Regiospecific Plasmonic Assemblies for in Situ Raman Spectroscopy in Live CellsJournal of the American Chemical Society, 2011
- Helical Assemblies of Gold NanoparticlesSmall, 2011
- Gold nanorods 3D-supercrystals as surface enhanced Raman scattering spectroscopy substrates for the rapid detection of scrambled prionsProceedings of the National Academy of Sciences of the United States of America, 2011
- Side‐by‐Side and End‐to‐End Gold Nanorod Assemblies for Environmental Toxin SensingAngewandte Chemie, 2010
- Pyramidal and Chiral Groupings of Gold Nanocrystals Assembled Using DNA ScaffoldsJournal of the American Chemical Society, 2009
- Negative Refractive Index at Optical WavelengthsScience, 2007