Spectroscopies à l'échelle de la molécule individuelle : dynamique de force pour l'interaction d'oligopeptides sur or et diffusion Raman exaltée par effet de pointe sur rotaxanes

Abstract : Beyond simply imaging, near-field techniques allow to probe and control molecular interactions onto a reduced number of molecules, if not a single one. In this subject, we took advantage of two local-probe spectroscopies. On the one hand, dynamic force spectroscopy (AFM-DFS) was applied to measure interactions between the oligopeptide CK(AAAAK)2C and a gold surface. It revealed several signatures ranging from 100 to 300 pN and more rarely some signatures above 1 nN. In order to interpret this complex response, we tested the kinetic models of Bell-Evans and Friddle-De Yoreo generally applied in ligand-receptor systems onto our system when the loading rate, i.e. the variation of the applied force per unit of time, is varied. Several interpretation methods including or not the effect of the unfolding of the coupling agent into the loading rate expression were tested. A numeric tool was also developed for the automatic processing of the force curves. Biases related to under-sampling of data, due to manual selection, or due to variables classification and mis-representation were limited by the implementation of tools automating the whole process. On the other hand, coupled to Scanning Tunneling Microscopy (STM), tip enhanced Raman spectroscopy (TERS) allowed us to observe the vibrational signature of a giant rotaxane on a gold substrate. STM images performed in ambient conditions could moreover highlight domains with individual molecules.
Complete list of metadatas

Cited literature [132 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02180603
Contributor : Abes Star <>
Submitted on : Thursday, July 11, 2019 - 3:33:36 PM
Last modification on : Saturday, September 28, 2019 - 1:24:41 AM

File

2016PA066746.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02180603, version 1

Citation

Marie Steffenhagen. Spectroscopies à l'échelle de la molécule individuelle : dynamique de force pour l'interaction d'oligopeptides sur or et diffusion Raman exaltée par effet de pointe sur rotaxanes. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2016. Français. ⟨NNT : 2016PA066746⟩. ⟨tel-02180603⟩

Share

Metrics

Record views

113

Files downloads

35