Probing the Ag, Au, and Cu electrode/pyridine-α-hydroxymethyl biphenyl phosphine oxide isomer interface with SERS

Characterization of the surface geometry of acetyl-[Leu 28,31 ]-NPY(24-36), a selective Y 2 receptor agonist, onto the Ag and Au surfaces

“…Another important aspect of the proposed adsorption model of acetyl-[Leu 28,31 ]-NPY (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) onto all the Ag and Au surfaces refers to the enhancement of the Arg residue and amide bond vibrations. The c.a.…”

“…The morphology of the electrochemically roughened Ag and Au electrode surfaces was examined by AFM [36] (see Fig. 1c and d).…”

“…First, the electrode was subjected to 3-5 ORC in the potential range of 2.100-0.000 V (with a scan rate of 100 mV/s). Second, 20 ORC were performed at the potential range between 0.000-1.600 V. Third, the electrode was flushed with deionized water and placed in the cell filled with a 0.1 M NaCl solution at the potential À1.000 V for 60 s. The roughening process of the Au electrode was conducted by using a 50-fold potential scan in the range between À0.300 to 1.300 V with a 500 mV/s scan rate; the pauses at the negative and positive potentials were 90 and 2 s, respectively [36,38,39]. The cyclic voltammograms ( Fig.…”

“…1a and b [31,34]) and roughened in the oxidation-reduction cycles Ag (20-100 nm) ( Fig. 1c [35,36]) and Au (100-500 nm) ( Fig. 1d [35,36]) surfaces are discussed.…”

“…The SERS phenomenon, by comparative analysis of the wavenumber, enhancement, and broadness of the corresponding Raman and SERS signals from the specific peptide regions, being either in close proximity or adsorbed onto a metal surface, allows to predict the possible metallic surface/molecule interactions [27] and hence, how molecule interacts with the surrounding medium or binds to its potential receptor [28][29][30]. Previously, we have presented the spectroscopic analysis of NPY and its native NPY , NPY , and NPY (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) and mutated acetyl-[Leu 28,31 ]-NPY(24-36) Cterminal fragments, acting on the Y 2 receptors, non-adsorbed and adsorbed onto the colloidal silver surface by normal Raman spectroscopy (RS) and SERS technique, respectively [31]. Our findings have demonstrated that the NPY(32-36) C-terminal fragment of all the investigated peptides was involved in the adsorption process onto the Ag substrate [31].…”