0000000000598905
AUTHOR
Nordin Félidj
New insight into the aptamer conformation and aptamer/protein interaction by surface-enhanced Raman scattering and multivariate statistical analysis
International audience; We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced. We demonstrate that the aptamer orientation and thus its flexibility rely strongly on the presence of a spacer …
Influence of the Number of Nanoparticles on the Enhancement Properties of Surface-Enhanced Raman Scattering Active Area: Sensitivity versus Repeatability
In the present work, the combination of chemical immobilization with electron beam lithography enables the production of sensitive and reproducible SERS-active areas composed of stochastic arrangements of gold nanoparticles. The number of nanoparticles was varied from 2 to 500. Thereby a systematic analysis of these SERS-active areas allows us to study SERS efficiency as a function of the number of nanoparticles. We found that the experimental parameters are critical, in particular the size of the SERS-active area must be comparable to the effective area of excitation to obtained reproducible SERS measurements. The sensitivity has also been studied by deducing the number of NPs that generat…
Discerning the Origins of the Amplitude Fluctuations in Dynamic Raman Nanospectroscopy
International audience; We introduce a novel experimental and analytical method for discerning rare surface-enhanced Raman scattering (SERS) events observable at the nanoscale. We show that the kinetics of the Raman activity recorded on an isolated nanostructure is punctuated by intense and rare events of large amplitude and spectral variations. The fluctuations of thousands of SERS spectra were analyzed statistically in terms of power density functions, and the occurrence of the rare events was quantified by a wavenumber statistics. Our analysis enables one to extract valuable and unique spectroscopic signature of Raman variations usually hidden in time-average or space-average measurement…