Study on the reversible changes of the surface properties of an L-cysteine self-assembled monolayer on gold as a function of pH.
A stimuli-response biological surface of L-cysteine was prepared on a polycrystalline gold surface from aqueous solution. The effect of the pH value of the rinsing solution on the surface composition was studied with X-ray photoelectron spectroscopy (XPS). Qualitative and quantitative analysis of the amino, carboxyl, and thiol functional groups of these self-assembled monolayers indicate that L-cysteine molecules exist in the neutral and zwitterionic forms and that they are sensitive to the pH of the rinsing solution. In addition, the wetting properties of the functionalized surface were studied by contact angle (CA) analysis: they were also dependent on the pH of the rinsing solution. Furthermore, it was shown that this functionalization process was reversible.
Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany.
Andrei-Daniel
AD
Filimon
Peter
P
Jacob
Roland
R
Hergenröder
Astrid
A
Jürgensen
D001672:Biocompatible Materials / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D056951:Photoelectron Spectroscopy; D012996:Solutions; D013499:Surface Properties; D014867:Water
D001672:Biocompatible Materials; D012996:Solutions; D014867:Water; D006046:Gold; D003545:Cysteine