SERS Investigation on Oligopeptides Used as Biomimetic Coatings for Medical Devices (original) (raw)
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The surface‐enhanced Raman scattering spectra of 5 amphiphilic oligopeptides derived from EAK16 (AEAEAKAK) 2 , used as biomimetic coatings for medical devices, were obtained at 10 −5 –10 −6 M in order to study the effects of systematic amino acid substitution along the peptide chain on the corresponding interaction with Ag colloidal nanoparticles. In addition, quantum‐mechanical data on 2 of the examined peptides were very useful for clarifying the assignment of bands, widely debated in the literature. In general, the peptide–nanoparticles interaction takes place through the COO − groups. The substitution of Ala by 2‐aminobutanoic acid in the sequence, corresponding to an increase of the hydrophobic chain length, is able to affect the peptide–Ag colloid interaction. It strengthens the interaction with NH 3 + groups, mediated by the Cl − anions present in the colloidal solution, although the charge transfer interaction with the COO − ions remains the dominant interaction mechanism. When Tyr substitutes the hydrophobic Ala, the interaction mechanism is strongly affected because it takes mainly place through the Tyr residues, where the aromatic rings are predominantly perpendicular to the silver surface, partly as tyrosinate ion. Thus, the addition of the Arg‐Gly‐Asp sequence, useful to provide control on the bioactivity of the bone regeneration materials, does not change the interactions with the colloid, because the spacer amino acid substitution is the main factor affecting the peptide–nanoparticle interactions.
Journal of Molecular Liquids, 2019
The surface-enhanced Raman scattering spectra of 5 amphiphilic oligopeptides derived from EAK16 (AEAEAKAK) 2 , used as biomimetic coatings for medical devices, were obtained at 10 −5-10 −6 M in order to study the effects of systematic amino acid substitution along the peptide chain on the corresponding interaction with Ag colloidal nanoparticles. In addition, quantum-mechanical data on 2 of the examined peptides were very useful for clarifying the assignment of bands, widely debated in the literature. In general, the peptide-nanoparticles interaction takes place through the COO − groups. The substitution of Ala by 2-aminobutanoic acid in the sequence, corresponding to an increase of the hydrophobic chain length, is able to affect the peptide-Ag colloid interaction.
Surface enhanced Raman scattering of amino acids and peptides
physica status solidi (c), 2009
The surface enhanced raman scattering (SERS) signal from the L-tyrosine (tyr) molecule adsorbed on gold nanoparticles (Au-tyr) is compared with the SERS signal assisted by the presence of gadolinium ions (Gd 3+) coordinated with the Au-tyr system. An enhancement factor of the SERS signal in the presence of Gd 3+ ions was ∼5 times higher than that produced by L-tyrosine adsorbed on gold nanoparticles. The enhancement of the SERS signal can be attributed to a corresponding increase in the local electric field due to the presence of Gd 3+ ions in the vicinity of a gold dimer configuration. This scenario was confirmed by solving numerically Maxwell equations, showing an increase of 1 order of magnitude in the local electric scattered field when the Gd 3+ ion is located in between a gold dimer compared with naked gold nanoparticles.
Journal of the Chilean Chemical Society
The development of new biomaterials has gained increasing attention in the last decade. One of the most important aspects in the development of these new materials is to understand the chemical cues presents in the native niche. Among all the techniques currently available for measuring those interactions, Raman spectroscopy offers a unique and non-invasive tool for exploring the behavior of the components within a given biomaterial and their surrounding microenvironment. This technique exploits the unique molecular vibrational fingerprints for pinpointing those interactions. The vibrational response can be improved to the single molecule level, in the presence of metal nanoparticles (NPs) with plasmonic properties (silver, gold and copper) in the so-called Surface-Enhanced Raman Scattering (SERS), which can be used for in-situ measurements. Another technique recently developed is the Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS), which overcomes signal contamination from chemical interactions between biomolecules and the metal surface; it does this by coating the metal surface with an inert layer of alumina or silica. In the present contribution, the role and the applications of Raman, SERS and related spectroscopic techniques in the study of biomolecules in biomaterials are reviewed and discussed.
Journal of Raman Spectroscopy, 2010
The synergistic effect produced by nanoparticles when incorporated into different systems used as analytical tools represents a growing research field nowadays. On the other hand, the study of interactions involving pharmacological drugs and biological membranes using phospholipids as mimetic systems is a research field already well established. Here, we combine both the anionic phospholipid dipalmitoyl phosphatidyl glycerol (DPPG) and negative Ag nanoparticles (AgNP) to form layer-by-layer (LbL) multilayered films using the cationic polymer poly(allylamine hydrochloride) (PAH) as the supporting polyelectrolyte, which were further investigated in the presence of a phenothiazine compound (methylene blue-MB). The molecular architecture of the LbL films in terms of controlled growth, morphology with micro and nanometer spatial resolutions, and dispersion of both AgNP and MB within the DPPG matrix was determined combining spectroscopy [ultraviolet-visible (UV-Vis) absorption and micro-Raman spectroscopy] and microscopy [scanning electron microscopy (SEM) and atomic force microscopy (AFM)]. The results showed that the LbL films can be grown in a controlled way at nanometer thickness scale with the surface morphology susceptible to the presence of both AgNP and MB. The surface-enhanced phenomenon was applied to investigate the LbL films taking the advantage of the strong surface-enhanced resonance Raman scattering (SERRS) signal presented by the MB molecules. Besides, as MB is a pharmacological drug of interest, its molecular arrangements when dispersed in LbL films containing DPPG, which is the biological membrane mimetic system here, were investigated. In this case, the AgNP played a key role in achieving the MB SERRS signal.
Journal of Raman Spectroscopy, 2013
EAK16 (AEAEAKAKAEAEAKAK) and seven alternating polar/hydrophobic oligopeptides (derived from EAK16 by primary structure modifications) were tested for their resistance to free radical attack, in view of their possible use as biomimetic coatings of biomedical devices; in fact, oxidative radical stress, mainly due to hydroxyl radicals ( • OH), is a common physiological condition occurring under acute or chronic inflammatory response. • OH radicals, mimicking an endogenous radical stress, were generated by gamma-radiolysis of water solutions. IR and Raman spectroscopies were used to investigate the damages induced by free radicals on the oligopeptides, in particular on their folding and inter-chain interactions.
Journal of Raman Spectroscopy, 1990
Surface-enhanced Raman (SER) spectra of water-soluble proteins (lysozyme and bovine serum albumin), dipeptides and amino acids were analysed. Chemisorption is a necessary condition for the appearance of SER spectra on silver electrodes and hydrosols for these compounds. The Raman cross-section enhancement per molecule may reach a factor of 10s-106, depending closely on the frequency of the vibration band considered. The mechanism of enhancement has a short-range character and is attributed to the rc-electron complexes of the aromatic amino acids sidechains and u-complexes of the molecular group containing unsbared electron pairs with the metal. The effect of induced optical activity in the visible region for aromatic amino acids adsorbed by silver hydrosols has been elucidated.
Journal of Nanoparticle Research, 2018
It is well known that when nanoparticles (NPs) are exposed to biological fluid, it results into formation of nanoparticle protein corona, which has been the subject of extensive studies for the development of targeted drug delivery. In this work, we demonstrated the dynamic light scattering, fluorescence, and UV-visible spectroscopy as quantitative and qualitative tools to monitor adsorption of BSA protein onto silver nanoparticles (AgNPs). The adsorption resulted in significant gradual increase in average hydrodynamic radius of BSA-AgNP corona from 24 to 35 nm and its attainment of equilibrium point (saturation) that correlated with albumin concentration enables condition for bound and unbound protein adsorption to be interpreted. Using DLS, the dissociation constant (K D) was obtained for soft corona to be 2.09 ± 0.30 μM. The UV-visible and fluorescence spectroscopy results were correlated with DLS. Loss of percent helicity in secondary structure of adsorbed BSA was monitored in both coronas as compared to native protein. Both coronas were found to be biocompatible with RBC membrane. Further, the results of adsorption isotherm model were used to validate the multilayer formation of albumin protein on silver nanoparticles. The obtained results would be relevant in the drug design development for tumor-targeted therapy.