Oxidative stress may cause extended tyrosine posttranslational modifications of peptides and proteins. The 3-nitro-L-tyrosine (Nit), which is typically formed, affects protein behavior during neurodegenerative processes, such as Alzheimer's and Parkinson's diseases. Such metabolic products may be conveniently detected at very low concentrations by surface enhanced Raman spectroscopy (SERS). Previously, we have explored the SERS detection of the Nit NO2 bending vibrational bands in a presence of hydrogen chloride (Niederhafner et al., Amino Acids 53:517-532, 2021, ibid). In this article, we describe performance of a new SERS substrate, "pink silver", synthesized photochemically. It provides SERS even without the HCl induction, and the acid further decreases the detection limit about 9 times. Strong SERS bands were observed in the asymmetric (1550-1475 cm-1) and symmetric (1360-1290 cm-1) NO stretching in the NO2 group. The bending vibration was relatively weak, but appeared stronger when HCl was added. The band assignments were supported by density functional theory modeling.

• Klíčová slova
• Nitration, Oxidative stress, Photochemical synthesis, Posttranslational protein modification (PTM), Silver colloids, Surface enhanced Raman spectroscopy (SERS),
• MeSH
• oxid dusičitý MeSH
• peptidy MeSH
• proteiny MeSH
• Ramanova spektroskopie * metody   MeSH
• stříbro * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• oxid dusičitý MeSH
• peptidy MeSH
• proteiny MeSH
• stříbro * MeSH

Arsenic of natural or industrial origin often occurs in water and makes it impotable. Due to its high toxicity, very sensitive detection is required. In the present study an ultra-sensitive arsenite (As3+) sensing is reported, based on aggregation-aided surface-enhanced Raman scattering (AA-SERS) of modified silver colloids. SERS intensity of mercapto-compounds attached to the colloidal silver nanoparticles surface is greatly increased in the presence of arsenic. Colloid aggregation is facilitated by cross-linking; a meshwork consisting of arsenic atoms and glutathione bridges is formed, as indicated by UV-Vis absorption spectroscopy, TEM and Raman imaging. The best 2-mercaptopyridine reporter molecule makes it possible to directly detect As3+ at concentrations as low as 0.5 ppb, which is better than achieved by the SERS technique so far.

• Klíčová slova
• Arsenic detection, Colloid cross-linking, Silver nanoparticles, Surface-enhanced Raman scattering,
• MeSH
• arsen * MeSH
• kovové nanočástice * MeSH
• Ramanova spektroskopie MeSH
• stříbro MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arsen * MeSH
• colloidal silver MeSH Prohlížeč
• stříbro MeSH

Surface-enhanced Raman spectroscopy (SERS) is an extremely powerful analytical tool, which not only yields information about the molecular structure of the analyte in the form of characteristic vibrational spectrum but also gives sensitivities approaching those in fluorescence spectroscopy. The SERS measurement on the microfluidic platform provides possibility to manufacture the device with design perfectly fulfilling the needs of the application with minimal sample consumption. This review aims at describing basic strategies for SERS measurement in microfluidic devices published in the last decade and covers current trends in microfluidics with SERS detection in the field of bioanalysis and approaches toward on-line coupling of liquid-based separation techniques with SERS detection.

• Klíčová slova
• Microfluidics, Nanoparticles, Separation, Surface-enhanced Raman spectroscopy,
• MeSH
• DNA analýza   MeSH
• fyzikální jevy MeSH
• kovové nanočástice chemie   MeSH
• limita detekce MeSH
• mikrofluidní analytické techniky metody   MeSH
• povrchové vlastnosti MeSH
• proteiny analýza   MeSH
• Ramanova spektroskopie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• DNA MeSH
• proteiny MeSH

Currently, trace detection of drugs, medicinal products, psychoactive substances, poisons and other natural or synthetic compounds in the human body has become one of the most important areas of interest in medicine, toxicology and forensic research. Due to the rapid development of nanotechnology, applications in forensic and biological sciences, food industry and art preservation there is an increasing interest in surface-enhanced Raman scattering (SERS) spectroscopy as a technique capable of low detection limits in the analysis of small amounts of studied analytes. In this study, different excitation wavelengths (785 nm and 1064 nm) were used to find the appropriate experimental conditions for the detection and identification of medically significant alkaloids - atropine and pergolide - by means of surface-enhanced Raman scattering spectroscopy. SERS spectra of selected alkaloids were measured in the concentration range 10-3-10-9 mol∙L-1 using large-scaled platinum substrates coated with electrochemically prepared gold or silver SERS-active layers. Identification was based on the assignment of surface-enhanced characteristic vibrational bands using theoretical (DFT) calculations and comparing them with normal (non-enhanced) Raman spectra of pure compounds. All sets of spectral data were subjected to multivariate statistical approach (partial least squares regression) aiming at prediction of alkaloids concentration in developed models and its comparison with experimental results.

• Klíčová slova
• Atropine, Gold substrates, Pergolide, Raman spectroscopy, SERS, Silver substrates,
• MeSH
• adjuvancia anestetická analýza   MeSH
• agonisté dopaminu analýza   MeSH
• atropin analýza   MeSH
• metoda nejmenších čtverců MeSH
• pergolid analýza   MeSH
• Ramanova spektroskopie metody   MeSH
• stříbro chemie   MeSH
• zlato chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adjuvancia anestetická MeSH
• agonisté dopaminu MeSH
• atropin MeSH
• pergolid MeSH
• stříbro MeSH
• zlato MeSH

Optofluidics, a research discipline combining optics with microfluidics, currently aspires to revolutionize the analysis of biological and chemical samples, e.g., for medicine, pharmacology, or molecular biology. In order to detect low concentrations of analytes in water, we have developed an optofluidic device containing a nanostructured substrate for surface enhanced Raman spectroscopy (SERS). The geometry of the gold surface allows localized plasmon oscillations to give rise to the SERS effect, in which the Raman spectral lines are intensified by the interaction of the plasmonic field with the electrons in the molecular bonds. The SERS substrate was enclosed in a microfluidic system, which allowed transport and precise mixing of the analyzed fluids, while preventing contamination or abrasion of the highly sensitive substrate. To illustrate its practical use, we employed the device for quantitative detection of persistent environmental pollutant 1,2,3-trichloropropane in water in submillimolar concentrations. The developed sensor allows fast and simple quantification of halogenated compounds and it will contribute towards the environmental monitoring and enzymology experiments with engineered haloalkane dehalogenase enzymes.

• Klíčová slova
• 1,2,3-trichloropropane, Klarite 312, chloroalkane, microfluidics, surface enhanced Raman spectroscopy,
• Publikační typ
• časopisecké články MeSH

Efficient separation and sensitive identification of pathogenic bacterial strains is essential for a prosperous modern society, with direct applications in medical diagnostics, drug discovery, biodefense, and food safety. We developed a fast and reliable method for antibody-based selective immobilization of bacteria from suspension onto a gold-plated glass surface, followed by detection using strain-specific antibodies linked to gold nanoparticles decorated with a reporter molecule. The reporter molecules are subsequently detected by surface-enhanced Raman spectroscopy (SERS). Such a multi-functionalized nanoparticle is called a SERS-tag. The presented procedure uses widely accessible and cheap materials for manufacturing and functionalization of the nanoparticles and the immobilization surfaces. Here, we exemplify the use of the produced SERS-tags for sensitive single-cell detection of opportunistic pathogen Escherichia coli, and we demonstrate the selectivity of our method using two other bacterial strains, Staphylococcus aureus and Serratia marcescens, as negative controls. We believe that the described approach has a potential to inspire the development of novel medical diagnostic tools for rapid identification of bacterial pathogens.

• Klíčová slova
• Escherichia coli, SERS-tag, sandwich immunoassay, single-cell detection,
• MeSH
• Escherichia coli MeSH
• kovové nanočástice * chemie   MeSH
• protilátky chemie   MeSH
• Ramanova spektroskopie * metody   MeSH
• Staphylococcus aureus MeSH
• zlato chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• protilátky MeSH
• zlato MeSH

Gliomas present one of the most prevalent malignant tumors related to the central nervous system. Surgical extraction is still a preferred route for glioma treatment. Nonetheless, neurosurgeons still have a considerable challenge to detect actual margins of the targeted glioma intraoperatively and correctly because of its great natural infiltration. Here we evaluated the possibility of using surface-enhanced Raman spectroscopy to analyze freshly resected brain tissues. The developed method is based on the application of Au@ZrO2 nanosensor. The plasmonic properties of the sensor were first tested on the analysis of Rhodamine 6G, where concentrations down to 10-7 mol/L can be successfully detected. We also compared the performance of the nanosensor with silver plasmonic nanoparticles, where similar results were obtained regarding the reduction of the fluorescence background and enhancement of the intensity of the measured analytical signal. However, application of silver nanospheres led to increased variations in spectral data due to its probable aggregation. Applied ZrO2@Au nanosensor thus dramatically lowers the fluorescence present in the Raman data, and considerably improves the quality of the measured signal. The developed method allows for rapid discrimination between the glioma's periphery and central parts, which could serve as a steppingstone toward highly precise neurosurgery.

• Klíčová slova
• Au nanospheres, Gliomas, Nanomaterials, Raman spectroscopy, SERS, ZrO(2),
• MeSH
• gliom * MeSH
• kovové nanočástice * chemie   MeSH
• lidé MeSH
• nanokuličky * chemie   MeSH
• Ramanova spektroskopie metody   MeSH
• stříbro chemie   MeSH
• zlato chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• stříbro MeSH
• zlato MeSH

Experimental results obtained in different laboratories world-wide by researchers using surface-enhanced Raman scattering (SERS) can differ significantly. We, an international team of scientists with long-standing expertise in SERS, address this issue from our perspective by presenting considerations on reliable and quantitative SERS. The central idea of this joint effort is to highlight key parameters and pitfalls that are often encountered in the literature. To that end, we provide here a series of recommendations on: a) the characterization of solid and colloidal SERS substrates by correlative electron and optical microscopy and spectroscopy, b) on the determination of the SERS enhancement factor (EF), including suitable Raman reporter/probe molecules, and finally on c) good analytical practice. We hope that both newcomers and specialists will benefit from these recommendations to increase the inter-laboratory comparability of experimental SERS results and further establish SERS as an analytical tool.

• Klíčová slova
• Raman spectroscopy, SERS, enhancement factor, quantitative analysis,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Surface-enhanced Raman scattering (SERS) spectroscopy and surface-enhanced infrared absorption (SEIRA) spectroscopy are analytical tools suitable for the detection of small amounts of various analytes adsorbed on metal surfaces. During recent years, these two spectroscopic methods have become increasingly important in the investigation of adsorption of biomolecules and pharmaceuticals on nanostructured metal surfaces. In this work, the adsorption of B-group vitamins pyridoxine, nicotinic acid, folic acid and riboflavin at electrochemically prepared gold and silver substrates was investigated using Fourier transform SERS spectroscopy at an excitation wavelength of 1,064 nm. Gold and silver substrates were prepared by cathodic reduction on massive platinum targets. In the case of gold substrates, oxidation-reduction cycles were applied to increase the enhancement factor of the gold surface. The SERS spectra of riboflavin, nicotinic acid, folic acid and pyridoxine adsorbed on silver substrates differ significantly from SERS spectra of these B-group vitamins adsorbed on gold substrates. The analysis of near-infrared-excited SERS spectra reveals that each of B-group vitamin investigated interacts with the gold surface via a different mechanism of adsorption to that with the silver surface. In the case of riboflavin adsorbed on silver substrate, the interpretation of surface-enhanced infrared absorption (SEIRA) spectra was also helpful in investigation of the adsorption mechanism.

• MeSH
• adsorpce MeSH
• Ramanova spektroskopie přístrojové vybavení   metody   MeSH
• spektrální analýza přístrojové vybavení   metody   MeSH
• stříbro chemie   MeSH
• vitamin B komplex analýza   MeSH
• zlato chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• stříbro MeSH
• vitamin B komplex MeSH
• zlato MeSH

Plasmon-driven reactions on plasmonic nanoparticles (NPs) occur under significantly different conditions from those of classical organic synthesis and provide a promising pathway for enhancing the efficiency of various chemical processes. However, these reactions can also have undesirable effects, such as 4-mercaptophenylboronic acid (MPBA) deboronation. MPBA chemisorbs well to Ag NPs through its thiol group and can subsequently bind to diols, enabling the detection of various biological structures by surface-enhanced Raman scattering (SERS), but not upon its deboronation. To avoid this reaction, we investigated the experimental conditions of MPBA deboronation on Ag NPs by SERS. Our results showed that the level of deboronation strongly depends on both the morphology of the system and the excitation laser wavelength and power. In addition, we detected not only the expected products, namely thiophenol and biphenyl-4,4-dithiol, but also 4-nitrothiophenol (NTP). The crucial reagent for NTP formation was an oxidation product of hydroxylamine hydrochloride, the reduction agent used in Ag NP synthesis. Ultimately, this reaction was replicated by adding NaNO2 to the system, and its progress was monitored as a function of the laser power, thereby identifying a new reaction of plasmon-driven -B(OH)2 substitution for -NO2.

• Klíčová slova
• 4-Mercaptophenyl boronic acid, 4-Nitrobenzenethiol, Nanoparticles, SERS, Surface plasmon resonance, Surface-enhanced Raman scattering,
• Publikační typ
• časopisecké články MeSH