Thiols

This work describes kinetic studies of the catalytic oxidation of thiols (RSHs) found in kerosene to disulphides using a magnetically separable iron oxide coated Mg-Al layered double hydroxide supported tetra-sulphonated cobalt phthalocyanine (CoPcS/LDH@Fe 3 O 4) catalyst in an alkali-free environment. Using 1-octanethiol as a representative RSH, we investigated the effects of different experimental parameters on RSH oxidation kinetics, including catalyst concentration, temperature (30–60 °C), and initial thiol concentration ([RSH] 0 , 100–300 ppm). The catalyst concentration was varied so that the [RSH] 0 /[Co] tot molar ratio ranged from 45 to 180. Based on the results, we propose a mechanistic rate expression to explain the observed oxidation of RSH in the presence of the CoPcS/LDH@Fe 3 O 4 catalyst. The proposed rate law resembles double substrate Michaelis-Menten kinetics, however, for commonly encountered industrial conditions, we were able to simplify it to a linear form. This rate law for RSH oxidation can be used to design industrial reactors for an alkali-free sweetening process.

Penetrating microscale microelectrodes made from flexible polymers tend to bend or deflect and may fail to reach their target location. The development of flexible neural probes requires methods for reliable and controlled insertion into the brain. Previous approaches for implanting flexible probes into the cortex required modifications that negate the flexibility, limit the functionality, or restrict the design of the probe. This study investigated the use of an electronegative self-assembled monolayer (SAM) as a coating on a stiff insertion shuttle to carry a polymer probe into the cerebral cortex, and then the detachment of the shuttle from the probe by altering the shuttle's hydrophobicity.

Polydimethylsiloxane (PDMS) and polyimide probes were inserted into an agarose in vitro brain model using silicon insertion shuttles. The silicon shuttles were coated with a carboxyl terminal SAM. The precision of insertion using the shuttle was measured by the percentage displacement of the probe upon shuttle removal after the probe was fully inserted. The average relative displacement of polyimide probes inserted with SAM-coated shuttles was (1.0 ± 0.66)% of the total insertion depth compared to (26.5 ± 3.7)% for uncoated silicon shuttles. The average relative displacement of PDMS probes was (2.1 ± 1.1)% of the insertion depth compared to 100% (complete removal) for uncoated silicon shuttles. SAM-coated shuttles were further validated through their use to reliably insert PDMS probes in the cerebral cortex of rodents. This study found that SAM-coated silicon shuttles are a viable method for accurately and precisely inserting flexible neural probes in the brain.

As part of a drug discovery programme to discover new treatments for human African trypanosomiasis, recombinant trypanothione reductase from Trypanosoma brucei has been expressed, purified and characterized. The crystal structure was solved by molecular replacement to a resolution of 2.3 Å and found to be nearly identical to the T. cruzi enzyme (root mean square deviation 0.6 Å over 482 C atoms). Kinetically , the K m for trypanothione disulphide for the T. brucei enzyme was 4.4-fold lower than for T. cruzi measured by either direct (NADPH oxidation) or DTNB-coupled assay. The K m for NADPH for the T. brucei enzyme was found to be 0.77 M using an NADPH-regenerating system coupled to reduction of DTNB. Both enzymes were assayed for inhibition at their respective S = K m values for trypanothione disulphide using a range of chemotypes, including CNS-active drugs such as clomipramine, trifluoperazine, thiori-dazine and citalopram. The relative IC 50 values for the two enzymes were found to vary by no more than 3-fold. Thus trypanothione reductases from these species are highly similar in all aspects, indicating that they may be used interchangeably for structure-based inhibitor design and high-throughput screening.

A Glutathione (GSH) optical sensor with high sensitivity and exceptional selectivity was developed using one-step synthesized-upconversion nanoparticles (UCNPs, NaLuF4:Gd3+,Yb3+,Er3+) in conjunction with a Rhodamine B derivative (RBD). RBD was loaded on the surface of the UCNPs though non-covalent bonding to serve as an energy acceptor, while UCNPs served as energy donors. The sensor based on a coupling fluorescence resonance energy transfer (FRET) process at an excitation of 980 nm wavelength from UCNP to RBD with a ringopening process of RBD after the addition of GSH. The sensing probe exhibits a remarkable
limit of detection (LOD = 50 nM) for GSH through the enhancement of the fluorescence intensity of RBD at 592 nm, together with a concomitant reduction in the green band of the UCNPs. In addition, the sensing mechanism, characterization of UCNPs, and the selectivity of the fluorescence sensor toward GSH were discussed. The proposed sensor was evaluated on real human serum and urine samples and demonstrated as a highly selective and sensitive probe for the detection of GSH.

Dimethylsulphide (DMS) plays a major role in the global sulphur cycle. It has important implications for atmospheric chemistry, climate regulation, and sulphur transport from the marine to the atmospheric and terrestrial environments. In addition, DMS acts as an info-chemical for a wide range of organisms ranging from micro-organisms to mammals. Micro-organisms that cycle DMS are widely distributed in a range of environments, for instance, oxic and anoxic marine, freshwater and terrestrial habitats. Despite the importance of DMS that has been unearthed by many studies since the early 1970s, the understanding of the biochemistry, genetics, and ecology of DMS-degrading micro-organisms is still limited. This review examines current knowledge on the microbial cycling of DMS and points out areas for future research that should shed more light on the role of organisms degrading DMS and related compounds in the biosphere.

Hydrogen peroxide (H 2 O 2) is a key signaling agent. Its best characterized signaling actions in mammalian cells involve the early oxidation of thiols in cytoplasmic phosphatases, kinases and transcription factors. However, these redox targets are orders of magnitude less H 2 O 2-reactive and abundant than cytoplasmic peroxiredoxins. How can they be oxidized in a signaling time frame? Here we investigate this question using computational reaction-diffusion models of H 2 O 2 signaling. The results show that at H 2 O 2 supply rates commensurate with mitogenic signaling a H 2 O 2 concentration gradient with a length scale of a few tenths of μm is established. Even near the supply sites H 2 O 2 concentrations are far too low to oxidize typical targets in an early mitogenic signaling time frame. Furthermore, any inhibition of the peroxiredoxin or increase in H 2 O 2 supply able to drastically increase the local H 2 O 2 concentration would collapse the concentration gradient and/or cause an extensive oxidation of the peroxiredoxins I and II, inconsistent with experimental observations. In turn, the local concentrations of peroxiredoxin sulfenate and disulfide forms exceed those of H 2 O 2 by several orders of magnitude. Redox targets reacting with these forms at rate constants much lower than that for, say, thioredoxin could be oxidized within seconds. Moreover, the spatial distribution of the concentrations of these peroxiredoxin forms allows them to reach targets within 1 μm from the H 2 O 2 sites while maintaining signaling localized. The recruitment of peroxiredoxins to specific sites such as caveolae can dramatically increase the local concentrations of the sulfenic and disulfide forms, thus further helping these species to outcompete H 2 O 2 for the oxidation of redox targets. Altogether, these results suggest that H 2 O 2 signaling is mediated by localized redox relays whereby peroxiredoxins are oxidized to sulfenate and disulfide forms at H 2 O 2 supply sites and these forms in turn oxidize the redox targets near these sites.

The most commonly used solution in chrome plating bath is chromic acid (hexavalent Cr), and a considerable amount of mists is released into the air and consequently produce hazards to workers. Thus, the aim of this study was to evaluate whether the biomarker of exposure to metals, specially Cr levels, presents associations with hematological and biochemical parameters and if they can alter the activity of enzymes that contain thiol groups such as pyruvate kinase, creatine kinase, adenylate kinase, and δ-aminolevulinate dehydratase. Fifty male chrome plating workers were used for exposed group and 50 male non-exposed workers for control group. For that, biological monitoring was performed through quantification of metals on total blood and urine by inductively coupled plasma mass spectrometry (ICP-MS) and enzyme activity was performed by spectrometry in erythrocytes. In addition, chromium levels in water was quantified and ecotoxicology assay was performed with Allium cepa test. The results demonstrated that blood and urinary chromium levels in exposed group were higher than the control group (p < 0.0001). Furthermore, decreased activity of enzymes was found in those that contain thiol groups from exposed group when compared with the control group (p < 0.001). The water analysis did not present a statistical difference between control and exposed groups (p > 0.05), demonstrating that water did not seem to be the source of contamination. In summary, our findings indicated some toxicology effects observed in the exposed group, such as thiol enzyme inhibition, mainly associated with occupational exposure in chrome plating and besides the presence of other metals, and Cr demonstrated to influence the activity of the enzymes analyzed in this research.

This paper establishes the chemical nature of Pd nanoparticles protected by alkanethiolates that were prepared through a ligand place-exchange approach and the two-phase method, firstly developed for Au nanoparticles by Brust and Schiffrin. After ten years since the first study on this kind of Pd nanoparticles was published, the surface composition of the particles is a matter of debate in the literature and it has not been unambiguously assessed. The nanoparticles were studied by means of several techniques: UV-visible spectroscopy, scanning transmission electron microscopy (STEM), Fourier-transform infrared spectroscopy (FTIR), extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron spectroscopy (XPS). The experimental data, obtained for the 3 nm diameter Pd particles, prepared by both synthetic routes, are consistent with nanoparticles composed by Pd(0) cores surrounded by a submonolayer of sulfide species, which are protected by alkanethiolates. Also, we unambiguously demonstrate that the chemical nature of these particles is very similar to that experimentally found for alkanethiolate-modified bulk Pd. The results from this paper are important not only for handling thiolate-protected Pd nanoparticles in catalysis and sensing, but also for the basic comprehension of metallic nanoparticles and the relation of their surface structure whit the synthesis method.

This paper establishes the chemical nature of Pd nanoparticles protected by alkanethiolates that were prepared through a ligand place-exchange approach and the two-phase method, firstly developed for Au nanoparticles by Brust and Schiffrin. After ten years since the first study on this kind of Pd nanoparticles was published, the surface composition of the particles is a matter of debate in the literature and it has not been unambiguously assessed. The nanoparticles were studied by means of several techniques: UV-visible spectroscopy, scanning transmission electron microscopy (STEM), Fourier-transform infrared spectroscopy (FTIR), extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron spectroscopy (XPS). The experimental data, obtained for the 3 nm diameter Pd particles, prepared by both synthetic routes, are consistent with nanoparticles composed by Pd(0) cores surrounded by a submonolayer of sulfide species, which are protected by alkanethiolates. Also, we unambiguously demonstrate that the chemical nature of these particles is very similar to that experimentally found for alkanethiolate-modified bulk Pd. The results from this paper are important not only for handling thiolate-protected Pd nanoparticles in catalysis and sensing, but also for the basic comprehension of metallic nanoparticles and the relation of their surface structure whit the synthesis method.

Hünlich’s base modification has resulted in introducing a series of versatile Λ-shaped building blocks presented in this work. The methods are optimized to provide convenient approaches in the quicker production of these new building blocks in low-cost and low-risk.

The biocatalytic synthesis of phenothiazones and related compounds has been achieved in an aqueous system under mild conditions facilitated by laccase oxidation. It was found that by coupling 2-aminoth-iophenol directly with 1,4-quinones, the product yields could be significantly increased compared to generating the 1,4-quinones in situ from the corresponding hydroquinones via laccase oxidation. However, laccase still proved to be pivotal for achieving highest product yields by catalyzing the final oxidation step. Furthermore, a difference in reactivity of aromatic and aliphatic amines toward 1,4-naphthoquinone is observed. This study provides a sustainable approach to the synthesis of a biologically important class of compounds.

The increasing use of silver nanoparticles (AgNPs) in consumer products raises the risk of human toxicity. Currently, there are no therapeutic options or established treatment protocols in cases of AgNPs intoxication. We demonstrated previously that thiol antioxidants compounds can reverse the cytotoxicity induced by AgNPs in Huh-7 hepatocarcinoma cells. Here, we investigated the use of N-acetylcysteine (NAC) against the systemic toxic effects of AgNPs (79.3 nm) in rats. Biochemical, histopathological, hematological, and oxidative parameters showed that a single intravenous injection of AgNPs (5 mg/kg b.w.) induced deleterious effects such as hepatotox-icity, potentially as a result of AgNPs accumulation in the liver. Treatment with a single intraperitoneal injection of NAC (1 g/kg b.w.) one hour after AgNPs exposure significantly attenuated all toxic effects evaluated and altered the bioaccumulation and release patterns of AgNPs in rats. The findings show that NAC may be a promising candidate for clinical management of AgNPs intoxication. ARTICLE HISTORY

Photonic experiments are of key importance in life sciences but light-induced side effects are serious confounding factors. Here we introduce roNa V 2, an engineered voltage-gated Na + channel harboring a selenocysteine in its inactivation motif, as a non-photonic, sensitive, gateable, and reversible sensor for membrane-delimited reactive species. roNa V 2 allows for the assessment of chemical modification induced in fluorescence microscopy settings with high sensitivity and time resolution and it demonstrates the usefulness of ion channels as highly sensitive reporters of membrane processes. Cellular reactive species (RS), e.g., superoxide (O 2 −⋅), hydroxide (HO ⋅), hydrogen peroxide (H 2 O 2), and hypochlorous acid (HClO) play crucial roles in physiological processes, such as signal transduction, activation of nuclear transcription factors, gene expression, and immune regulation 1–3. However, excess RS modify lipids, proteins, and nucleic acids, and are often associated with adverse consequences such as neurodegeneration, ath-erosclerosis, diabetes, sepsis, and cancer 4. RS differ in their production, concentration, distribution, lifetime, molecular targets, and biological functions. Therefore, there is a clear demand for sensitive probes to precisely monitor cellular RS with spatio-temporal resolution to understand the multifaceted role of cellular RS in cell physiology. Recently, mutants and fusions of genetically encoded GFP (green fluorescent protein), for example, reduction and oxidation sensitive variants roGFP2 5 and Grx1-roGFP2 (Grx = glutaredoxin) 6 , received much attention for cellular RS monitoring. roGFP2 is a genetically engineered fluorescent redox reporter, which was developed by inserting a dithiol-disulfide pair into GFP. The breakage and the formation of the disulfide bridge in roGFP2 leads to a differential change in fluo-rescence at 400 nm and 470 nm excitation wavelength, thus yielding a ratiometric signal that reports on oxidative changes in its local environment. Fusion of human glutaredoxin-1 to roGFP2 provides strongly accelerated formation of a disulfide bridge and, hence, increases the sensitivity of Grx1-roGFP2 in the physiologically relevant range for glutathione-mediated RS modifications 6. These fluorescent reporters offer several useful features, such as the choice of localized sub-cellular targeting, real-time RS detection, and ratiometric observation that overcome artifacts arising due to photo-bleaching and inhomogeneous distribution of the sensors. However, there is the inherent problem of phototoxicity that can lead to lasting irreversible destruction of cellular structures and may even result in immediate alteration of molecular function. Despite the obvious detrimental consequences of visible light in cell physiological studies, the issue of phototoxicity has been only infrequently considered in life science research 7. The presence of intracellular flavin-containing oxidases, the cytochrome system, heme-containing proteins, and tryptophan-rich proteins not only confound with fluorescence techniques, they may also act as cellular photosensitizers and constitute the major source of light-induced RS 8–10. Moreover, photo-activated GFP disturbs cellular redox homeostasis either by producing endogenous superoxide or altering the glutathione homeostasis 11–13. Therefore, the potential interference of blue light as used for GFP-based imaging with the cellular redox system clearly demands for alternative tools or probes for monitoring cellular RS. Previously, we have reported a genetically engineered voltage-gated Na + (Na V) channel with a cysteine residue in its inactivation domain (roNa V 1; rNa V 1.4 mutant M1305C, also termed IFC) as a non-photonic RS sensor delimited to the cell membrane 14. Na V channels activate (open) and inactivate (close) rapidly in response to

Glyoxalase I (GLO1) is a putative drug target for trypanosomatids, which are pathogenic protozoa that include the causative agents of leishmaniasis. Significant sequence and functional differences between Leishmania major and human GLO1 suggest that it may make a suitable template for rational inhibitor design. L. major GLO1 was crystallized in two forms: the first is extremely disordered and does not diffract, while the second, an orthorhombic form, produces diffraction to 2.0 A ˚. Molecular-replacement calculations indicate that there are three GLO1 dimers in the asymmetric unit, which take up a helical arrangement with their molecular dyads arranged approximately perpendicular to the c axis. Further analysis of these data are under way.

Trypanothione replaces glutathione in defence against cellular damage caused by oxidants, xeno-biotics and methylglyoxal in the trypanosomatid parasites, which cause trypanosomiasis and leish-maniasis. In Leishmania major, the first step in methylglyoxal detoxification is performed by a trypanothione-dependent glyoxalase I (GLO1) containing a nickel cofactor; all other characterized eukaryotic glyoxalases use zinc. In kinetic studies L. major and human enzymes were active with meth-ylglyoxal derivatives of several thiols, but showed opposite substrate selectivities: N 1-glutathionylsper-midine hemithioacetal is 40-fold better with L. major GLO1, whereas glutathione hemithioacetal is 300-fold better with human GLO1. Similarly, S-4-bromobenzyl-glutathionylspermidine is a 24-fold more potent linear competitive inhibitor of L. major than human GLO1 (K i s of 0.54 m M and 12.6 m M, respectively), whereas S-4-bromobenzylglutathione is > 4000-fold more active against human than L. major GLO1 (K i s of 0.13 m M and > 500 m M respectively). The crystal structure of L. major GLO1 reveals differences in active site architecture to both human GLO1 and the nickel-dependent Escherichia coli GLO1, including increased negative charge and hydrophobic character and truncation of a loop that may regulate catalysis in the human enzyme. These differences correlate with the differential binding of glutathione and trypanothione-based substrates, and thus offer a route to the rational design of L. major-specific GLO1 inhibitors.

The first off–on probe, Mito-TRFS, for imaging the mitochondrial thioredoxin reductase (TrxR2) in live cells was reported. In a cellular model of Parkinson’s disease (PD), Mito-TRFS staining discloses a drastic decline of the TrxR2 activity, providing a mechanistic link of TrxR2 dysfunction to the etiology of PD.

A series of N-acetyl-S- [(3-hydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)methyl]-L-cysteine conjugates were obtained in good yields by acid-catalyzed condensation of substituted 2-hydroxy-1,4-naphthoquinones with N-acetyl-L-cysteine and paraformaldehyde. Based on this reaction, a first synthesis of fibrostatins B, C, and D was developed.

Described here is a UV photo-cross-linking method that utilizes the NBS (nucleotide binding site) for site-specific covalent functionalization of antibodies with reactive thiol moieties (UV-NBS(Thiol)), while preserving antibody activity. By synthesizing an indole-3-butyric acid (IBA) conjugated version of cysteine we site-specifically photo-cross-linked a reactive thiol moiety to antibodies at the NBS. This thiol moiety can then be used as an orthogonally reactive location to conjugate various types of functional ligands that possess a thiol reactive group through disulfide bond formation or reaction with a maleimide functionalized ligand. Our results demonstrate the utility of the UV-NBS(Thiol) method by successfully functionalizing a prostate specific antigen antibody (IgG(PSA)) with IBA-Thiol and subsequent reaction with maleimide-fluorescein. An optimal UV energy of 0.5-1.5 J/cm(2) was determined to yield the most efficient photo-cross-linking and resulted in 1-1.5 conjugations per antibody while preserving antibody/antigen binding activity and Fc recognition. Utilizing the IBA-Thiol ligand allows for an efficient means of site-specifically conjugating UV sensitive functionalities to antibody NBS that would otherwise not have been amenable by the previously described UV-NBS photo-cross-linking method. The UV-NBS(Thiol) conjugation strategy can be utilized in various diagnostic and therapeutic applications with nearly limitless potential for the preparation of site-specific covalent conjugation of affinity tags, fluorescent molecules, peptides, and chemotherapeutics to antibodies.

Electrodes prepared from overoxidized pyrrole, multi-walled carbon nanotubes (MWCNT) and cobalt phthalocyanine (CoPc) exhibit a clear catalytic activity for the electrooxidation of L-cysteine and reduced gluthatione. The electrodes are more stable than the ones modified by simple adsorption of CoPc and/or MW-CNT. Therefore, these materials offer a good alternative for the development of electrocatalytic applications and thiols detection in biological interest.

Objective: Alpha-lipoic acid (ALA) as a strong antioxidant has a protective effect. This study was designed to assess whether supplementation of maturation medium with ALA during in vitro maturation (IVM) can attenuate the toxic effect of ethanol. Materials and Methods: In this experimental study, to assess the antioxidant capacity of ALA challenged by 1% ethanol during in vitro maturation, immature ovine oocytes were exposed to 1% alcohol in the presence or absence of 25 µM ALA during oocyte maturation. The cumulus expansion index, intracellular reactive oxygen species (ROS), and thiol content levels were assessed in matured oocytes of various treatment groups. Consequently, the blastocyst formation rate of matured oocytes in various treatment groups were assessed. In addition, total cell number (TCN), cell allocation, DNA fragmentation, and relative gene expression of interested genes were assessed in resultant blastocysts. Results: The results revealed that alcohol significantly reduced cumulus cells (CCs) expansion index and blastocyst yield and rate of apoptosis in resultant embryos. Addition of 25 µM ALA to 1% ethanol during oocyte maturation decreased ROS level and elevated Thiolcontent. Furthermore, supplementation of maturation medium with ALA attenuated the effect of 1% ethanol and significantly increased the blastocyst formation and hatching rate as compared to control and ethanol groups. In addition, the quality of blastocysts produced in ALA+ethanol was improved based on the low number of TUNEL positive cells, the increased expression level of mRNA for pluripotency, and anti-oxidant markers, and decreased expression of apoptotic genes. Conclusion: The current findings demonstrate that ALA can diminish the effect of ethanol, possibly by decreasing the ROS level and increasing Thiolcontent during oocyte maturation. Using the ALA supplement may have implications in protecting oocytes from alcohol toxicity in affected patients.

Aim: In most Muslim societies the daily routine and lifestyle change markedly during the month of Ramadan because of fasting during daylight hours and the altered day and night rituals. These changes could potentially have significant metabolic effects. The aim of this study was to explore the effects of Ramadan fasting and the resultant lifestyle changes on the biochemical profile and oxidative stress markers in healthy adult males.
Material and Method: Forty-two healthy male volunteers following their usual Ramadan fasting routine were included in the study. The following serum variables were measured at the beginning and at the end of the month: triglycerides, total cholesterol, HDL cholesterol, non-HDL cholesterol, albumin, total protein, CRP, uric acid, ischemiamodified albumin (IMA), albumin adjusted-IMA (AAIMA), and thiol/disulfide homeostasis.
Results: Triglycerides, total cholesterol, non-HDL cholesterol, IMA and AAIMA levels were significantly higher on the last day of Ramadan compared to the first day (p<0.05). HDL cholesterol levels were statistically lower on the last day of Ramadan than the first day (p<0.05). However, there were no significant changes in the remaining variables (total albumin, uric acid, CRP, and thiol/disulfide homeostasis parameters).
Discussion: Lifestyle, nutritional, and diurnal rhythm changes during the month of Ramadan may be associated with hormonal and biorhythm alterations which could be responsible for the observed elevations in serum IMA, AAIMA and non–HDL cholesterol levels. However, further studies are required to ascertain the direct causes of these changes.
Keywords: Ramadan Fasting; Oxidative Stress; Ischemia Modified Albumin; Thiol/disulfide Homeostasis; Non-HDL Cholesterol

Carbon−carbon bond is one of the most ubiquitous molecular building blocks for natural and man-made materials. Rotational isomerization is fundamentally important for understanding the structure and reactivity of chemical and biological molecules. Reported herein is the first demonstration that a single C−C bond does not rotate in water. The two distal C−S bonds in both 1,2-ethanedithiolate (− S−CH 2 −CH 2 −S − , 1,2-EDT 2−) and 2,3-butanedithiolate (2,3-BuDT 2−) are exclusively in the trans conformer with reference to their respective center single C−C bond. In contrast, both trans and gauche conformers are observed in neutral 1,2-ethanedithiol (1,2-EDT) and 2, 3-butanedithiol (2,3-BuDT). The insight from this work should be important for understanding the charge effect on the molecular conformation in aqueous solutions.

A thiol-selective 2-methyl-3-phenacrylate scaffold with spatiotemporal control over delivery of a cargo is reported. The half-lives of decomposition could be tuned from 30 min to 1 day and the scaffold's utility in thiol-inducible fluorophore release in cell-free as well as within cells is demonstrated.

A simple method entirely based on solution chemistry to deposit metals on foreign substrates at underpotential conditions is described. The method allows deposition of extremely small amounts of metals under equilibrium conditions. Thiolate-covered bimetallic extended planar and nanoparticle surfaces can be easily prepared by this route using redox couples and solution pH to control the interfacial potential of the system.

In this paper, the synthesis of gold@gold(I)−thiolate core@shell nanoparticles is described for the first time. The chemical nature and structure of these nanoparticles were characterized by a multi-technique approach. The prepared particles consist of gold metallic cores, about 1 nm in size, surrounded by stable gold(I)−thiomalate shells (Au@Au(I)−TM). These nanoparticles could be useful in medicine due to the interesting properties that gold(I)−thiomalate has against rheumatoid arthritis. Furthermore, the described results give new insights in the synthesis and characterization of metallic and core@shell nanoparticles.