Localized surface plasmon resonance (LSPR) study of DNA hybridization at single nanoparticle transducers
- 957 Downloads
The effect of DNA–DNA interaction on the localized surface plasmon resonance of single 80 nm gold nanoparticles is studied. Therefore, both the attachment of the capture DNA strands at the particle surface and the sequence-specific DNA binding (hybridization) of analyte DNA to the immobilized capture DNA is subject of investigations. The influence of substrate attachment chemistry, the packing density of DNA as controlled by an assisting layer of smaller molecules, and the distance as increased by a linker on the LSPR efficiency is investigated. The resulting changes in signal can be related to a higher hybridization efficiency of the analyte DNA to the immobilized capture DNA. The subsequent attachment of additional DNA strands to this system is studied, which allows for a multiple step detection of binding and an elucidation of the resulting resonance shifts. The detection limit was determined for the utilized DNA system by incubation with various concentration of analyte DNA. Although the method allows for a marker-free detection, we show that additional markers such as 20 nm gold particle labels increase the signal and thereby the sensitivity significantly. The study of resonance shift for various DNA lengths revealed that the resonance shift per base is stronger for shorter DNA molecules (20 bases) as compared to longer ones (46 bases).
KeywordsLSPR Single nanoparticle spectroscopy DNA hybridization
The authors thank Marie Löchner, Nicole Wendt, and Martin Knoll for assistance with LSPR measurements. The work was supported by the German Research Foundation DFG (FR 1348/12-1), the European Science Foundation ESF (New Approaches to Biochemical Sensing with Plasmonic Nanobiophotonics–Plasmon-Bionanosense, short visit grant 3633) and by IRCSET–Marie Curie International Mobility Fellowship in Science, Engineering and Technology.
- Bohren CF, Huffman (2007) Absorption and scattering of light by small particles. Wiley, New YorkGoogle Scholar
- Demers LM, Mirkin CA, Mucic RC, Reynolds RA, Letsinger RL, Elghanian R, Viswanadham G (2000) A fluorescence-based method for determining the surface coverage and hybridization efficiency of thiol-capped oligonucleotides bound to gold thin films and nanoparticles. Anal Chem 72(22):5535–5541CrossRefGoogle Scholar
- Raschke G. (2005) Molekulare Erkennung mit einzelnen Gold–Nanopartikeln. Dissertation, LMU München: Fakultät für PhysikGoogle Scholar
- Schena M (2003) Microarray analysis. Wiley-Liss, HobokenGoogle Scholar