Monitoring of DNA–protein interaction with single gold nanoparticles by localized scattering plasmon resonance spectroscopy

• Published in: Methods (San Diego, Calif.) Calif.), 2013-12, Vol.64 (3), p.331-337
• Main Authors: Lo, Kin-Man, Lai, Chung-Yin, Chan, Ho-Man, Ma, Dik-Lung, Li, Hung-Wing
• Format: Article
• Language: English
• Subjects: DNA Topoisomerases, Type I - chemistry; DNA, Single-Stranded - chemistry; Gold - chemistry; Humans; Immobilized Nucleic Acids - chemistry; LSPR; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Microscopy, Electron, Transmission; Nanocomposites - chemistry; Particle Size; Protein Binding; Protein–DNA interactions; Single nanoparticles; Surface Plasmon Resonance
• ISSN: 1046-2023; 1095-9130
• DOI: 10.1016/j.ymeth.2013.08.002

•A label-free detection of DNA–protein interactions at single nanoparticles level.•The λmax shift in LSPR spectrum of individual AuNP was detected.•It is capable of revealing information such as particle–particle variations. We reported a sensitive detection system for measuring DNA–protein interaction at single plasmonic metal nanoparticles level by Localized Scattering Plasmon Resonance (LSPR) spectroscopy. As a proof of concept, DNA molecules were conjugated to gold nanoparticles (AuNPs) through gold–thiol chemistry and the resulted complex was served as single-particle probes of human topoisomerase I (TOPO). By recording the changes in Rayleigh light scattering signal of the individual nanoparticles upon protein binding, DNA–protein interaction was monitored and measured. The λmax shifts in LSPR spectrum of individual AuNP was found to be highly correlated with the amount of TOPO that bound onto. This technique provides a sensitive and high-throughput platform to screen and monitor accurately the specific biomolecular interactions. It is capable of revealing information such as particle–particle variations that might be buried in conventional bulk measurement.