Evaluation of Chemical Interactions between Small Molecules in the Gas Phase Using Chemical Force Microscopy

Autor: Jieun Lee, Soomi Ju, In Tae Kim, Sun-Hwa Jung, Sun-Joon Min, Chulki Kim, Sang Jun Sim, Sang Kyung Kim
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Sensors, Vol 15, Iss 12, Pp 30683-30692 (2015)
Druh dokumentu: article
ISSN: 1424-8220
DOI: 10.3390/s151229823
Popis: Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, we investigated the effect of humidity on the analysis of force-distance curves and the images in lateral force mode. Flat chemical patterns composed of different functional groups were made through micro-contact printing and lateral force mode provided more resolved analysis of the chemical patterns. From the images of 1-octadecanethiol/11-mercapto-1-undecanoic acid patterns, the amine group functionalized tip brought out higher contrast of the patterns than an intact silicon nitride tip owing to the additional chemical interaction between carboxyl and amine groups. For more complex chemical interactions, relative chemical affinities toward specific peptides were assessed on the pattern of 1-octadecanethiol/phenyl-terminated alkanethiol. The lateral image of chemical force microscopy reflected specific preference of a peptide to phenyl group as well as the hydrophobic interaction.
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