Distance-mediated plasmonic dimers for reusable colorimetric switches : a measurable peak shift of more than 60 nm
Ferhan, Abdul Rahim
Li, Chang Ming
Date of Issue2013
School of Chemical and Biomedical Engineering
The first reconfigurable colorimetric DNA switches based on target DNA binding are reported. This DNA binding actuates a change in the interparticle distance between gold nanoparticle dimers. A significant spectral shift of 68 nm is achievable from on-off switching. The reconfigurability is possible owing to thiol and EDC-imidazole coupling which anchors the DNA linkers to the nanoparticles. The huge spectral shift allows the unaided eye to observe single target biomolecular binding event in real time under a darkfield microscope. The limit-of-detection for target molecules in PBS and human serum are 10−13 M and 10−11 M respectively. An improved fabrication strategy via asymmetric functionalization is also described, assisted by solid phase synthesis which minimizes the formation of trimers and multimers.
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.