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In this study, we present surface-enhanced Raman spectroscopy (SERS) investigations of five analogs of a novel group of N-benzylamino(boronphenyl)methylphosphonic acids: N-benzylamino-(3-boronphenyl)-S-methylphosphonic acid (m-PhS), N-benzylamino-(4-boronphenyl)-S-methylphosphonic acid (p-PhS), N-benzylamino-(2-boronphenyl)-R-methylphosphonic acid (o-PhR), N-benzylamino-(3-boronphenyl)-R-methylphosphonic acid (m-PhR), and N-benzylamino-(4-boronphenyl)-R-methylphosphonic acid (p-PhR) deposited onto 10-nm gold nanoparticles in an aqueous solution at physiological pH (pH = 7). In addition, for the p-PhR molecule, the SERS spectra in the various conditions of pH levels of the solutions (from pH = 3 to 11) and phosphonic acid concentration (10−3–10−5 M) were measured. In general, the SERS spectral profiles indicate that at pH = 7, all of the aforementioned molecules interact with the colloidal gold surface via a boronphenyl ring. However, the orientation of the boronphenyl ring onto the substrate surface is different for each of the studied molecules. The boronic acid group of p-PhS and p-PhR binds to the gold nanoparticles, whereas the phosphonic acid group assists in the interaction with the substrate for p-PhR only. For all the molecules, the –CLCα(P)N– fragment distinctly influences the molecule/gold interactions, especially in the case of o-PhR. The previous differences in the compound behavior at the gold/liquid interface underline the role of an absolute configuration (–R and –S) and a type of isomer (orto-, meta-, and para-) on the SERS signals, which means their influence on the adsorbate geometry. Additionally, based on the SERS results for p-PhR in various environmental conditions, we draw conclusions about spectral changes (adsorbate geometry changes) as a result of the pH of solution and molecule concentration alternations.

Micro-Raman spectroscopy and optical microscopy under visible and ultraviolet light were applied to characterize the pigments, state of conservation, and painting techniques used in the 17th century panel painting‘Servilius Appius’, attributed to Isaac van den Blocke. This Golden Age work of art is located at the Gdańsk History Museum. Briefly, individual layers of six samples from different parts of the aforementioned painting were analyzed. A rich palette of white, yellow, red, blue, and black pigments was identified using micro-Raman spectroscopy. Optical microscopy was also employed to observe and analyze these layers. The obtained results were compared with the art history knowledge of the painting. Consequently, these studies enabled precise characterization of the type of lead tin yellow, the admixture of pigments used in the painting layers, and the type of ground layers, as well as the determination of the pictorial technique used in the process of creating this work of art.

Neurotensin (NT) is a naturally occurring neurotransmitter that mediates the metabotropic seven-transmembrane G protein- coupled receptors, namely NTR1s, richly expressed on tumor surface. Therefore, mutated active molecular fragments of NT that possess selective antagonist or weak agonist properties and the high af fi nity to NTR1 have attracted considerable interest for use in thrombus, in fl ammation, and imaging/treatment of tumors. In this work, SERS spectra of three N -terminal fragments of human NT (NT 1-6 ,NT 1-8 , and NT 1-11 ) and six speci fi cally mutated C -terminal fragments of human NT, including NT 8-13 , [Dab 9 ] NT 8-13 , [Lys 8 ,Lys 9 ]NT 8-13 , [Lys 8 -( W )-Lys 9 ]NT 8-13 , [Lys 9 ,Trp 11 ,Glu 12 ]NT 8-13 , and NT 9-13 , adsorbed onto nanometer-sized colloidal silver particles in an aqueous solution at pH level of the solution 2 are presented. A comparison was made between the struc- tures of the native and mutated fragments to determine how changes in peptide length and mutations of the structure in fl uenced the NT adsorption properties. Based on the interpretation of the obtained data, we showed that all of the investi- gated NT fragments, excluding [Lys 9 ,Trp 11 ,Glu 12 ]NT 8-13 , tended to adsorb on the silver surface mainly through the L-tyrosine residue and the carboxylate group. The Tyr ring lied more-or-less fl at on the silver surface. The hydrogen atom from the phenol group dissociated upon binding. On the other hand, [Lys 9 ,Trp 11 ,Glu 12 ]NT 8-13 bound to this substrate through the close to vertical co-pyrrole ring of the indole ring (Trp 11 ) and – COO - . Comparison of the presented data with those obtained earlier for NT allows to suggest that in the case of naturally occurring neurotensin, both Tyr residues together with the carboxylate group play crucial role in the binding to the nanome- ter-sized colloidal silver particles. This geometry of binding forces the NT molecule to lay fl at on the surface.

Raman (RS), surface-enhanced Raman scattering (SERS), electrochemistry, and isotopic effect methods were used to characterize selective adsorption of two isotopically labeled bradykinin analogues, [(Phe-D 5 ) 5 ]BK and [(Phe-D 5 ) 8 ]BK, a hormone which is known to be involved in small-cell and non-small-cell lung carcinoma and prostate cancer. The investigated analogues contain Phe residue, at position 5 or 8 in the amino acid sequence, substituted by Phe-D 5 ( fi ve protons of L-phenylalanine ring substituted by deuterium). [(Phe-D 5 ) 5 ]BK and [(Phe-D 5 ) 8 ]BK were immobilized onto electrochemically roughened Ag, Au, and Cu electrode surfaces under different applied electrode potentials ( 1.000 V to 0.200 V) in an aqueous solution containing 0.01 M phosphate buffer (pH=7.0) and 0.1 M Na 2 SO 4 . Based on the analyses of the spectral pro fi les in the 920 – 1050 cm 1 spectral range, speci fi c conclusions were drawn with respect to the Phe metal interactions and changes in the interaction that occurred when the adsorption conditions were varied.

Surface-enhanced Raman scattering, electrochemistry, and generalized two-dimensional correlation analysis (G2DCA) methods were used to characterize bradykinin (BK), a hormone which is known to be involved in small-cell and non-small-cell lung carcinoma and prostate cancer. BK was deposited onto Ag, Au, and Cu electrode surfaces under different applied electrode potentials ( 1.000V to 0.200V) in aqueous solutions. Based on the analysis of the enhancement, the broadening, and the shifts in the wavenumbers of individual bands, speci fi c conclusions were drawn regarding the peptide geometry and changes in this geometry that occurred when the electrode type and applied electrode potential were varied. Brie fl y, BK deposited onto the Ag, Au, and Cu electrode surfaces showed bands that were due to the vibrations of moieties in contact with or in close proximity to the electrode surfaces and were thus located on the same side of the polypeptide backbone. These moieties included the Phe, Arg, and Pro residues. The fi ndingsfor adsorbed BKwere fully supportedbyG2DCA,which also allowed ustodeterminethe order in which changes occurred when the electrode potential was changed. In addition, it was found that at negative electrode potentials, the Phe rings and methylene groups interact with Ag electrode surface. No such interaction was observed for Au and Cu electrodes.