0000000000199850
AUTHOR
Thibault Brulé
Sorting of Enhanced Reference Raman Spectra of a Single Amino Acid Molecule
In this contribution, we report the identification of the principal reference Raman spectra of a single cystein molecule. To that purpose, we design an active Surface Enhanced Raman Spectroscopy (SERS) template based on surfactant-less Chebyshev nanoparticles operating in a microfluidic platform. A principal component analysis is obtained from fluctuating spectra to sort the reference spectra of cystein. The assignment of Raman bands brings new insight into the conformation of an amino acid adsorbed onto gold nanoparticle.
Discrimination between Single Protein Conformations Using Dynamic SERS
In biomedicine and biophysics, the discrimination of protein conformations is of critical importance for identifying the unfolding states in the diagnosis of neurodegenerative diseases. We develop a dynamic Raman spectroscopic approach based on a statistical analysis of the time series of spectral fingerprints of single protein. We show that the unfolded state of bovine serum albumin can be identified in the time series using the fluctuations of the Raman bands of some amino acids, tryptophan, tyrosine, leucine, and histidine, acting as biomarkers. The statistical analysis induces also the sorting between physisorption and chemisorption events. This is confirmed by the spectral analysis of …
Spectral and temporal distribution of biomolecules by Dynamic SERS
In this thesis, the definition of SERS as a biosensor has been tested and a new approach developed for. Also, in terms of quantification, it has been shown that SERS can be an efficient tool. Concerning the selectivity, the spectral quality was improved. A low limit of detection associated to the statistical and dynamic approach allows a very good sensitivity (under the nanomolar). This approach also enables a high reproducibility in time of the sensor. Thus, as low as SERS does not well answer to the sensor capabilities in a classical approach, in our case the coupling between a non-functionalized GNPs substrate coupled with a microfluidic chip, all mounted on a confocal microscope for tem…
Sorting of Single Biomolecules based on Fourier Polar Representation of Surface Enhanced Raman Spectra
AbstractSurface enhanced Raman scattering (SERS) spectroscopy becomes increasingly used in biosensors for its capacity to detect and identify single molecules. In practice, a large number of SERS spectra are acquired and reliable ranking methods are thus essential for analysing all these data. Supervised classification strategies, which are the most effective methods, are usually applied but they require pre-determined models or classes. In this work, we propose to sort SERS spectra in unknown groups with an alternative strategy called Fourier polar representation. This non-fitting method based on simple Fourier sine and cosine transforms produces a fast and graphical representation for sor…