It is rapidly becoming evident that secreted vesicles, specifically exosomes, are the next generation of theranostic natural nanoparticles. "Theranostic " refers to the combined treatment and diagnosis of disease. Artificial nanoparticles have been widely used as theranostic molecules due to their unique properties. However, there are limitations to using them in clinical applications, mainly because of their toxicity, short-term circulation, and immunoge-nicity. Emerging evidence suggests that naturally occurring nanoparticles such as extracellular vesicles (EVs) may solve some of these limitations. One of many documented vesicles produced by cells, exosomes, are secreted by various cell types and under varying conditions. The small size range (30-120 nm), components, lack of toxicity, long-term circulation times, and low immunogenicity of exosomes make them very attractive natural nanoparticles to use in diagnosing and treating diseases. In addition to acting as drug and nucleic acid vehicles, exosomes can carry and deliver magnetic nanoparticles like iron oxide nanoparticles (IONPs), plasmonically active gold nanorods (AuNRs), hollow gold nanoparticles (HGNPs), and gold nanoparticles (AuNPs). Loading and/or labeling exosomes with strategic nanoparticles makes theranostics easier and more effective because exosomes can facilitate cell-cell interaction, which increases their targeting efficiency as well as their ability to aid photothermal therapy in vitro and in vivo. However, the methods and approaches to successfully label and track these nanostructures are still being refined by the life sciences community. In this Review, we will discuss notable exosome labeling approaches that have been studied to enable exosomes to carry active nanoparticles for diagnostic, therapeutic, and photothermal therapy purposes. We will represent specialIntscript the types of nanoparticles (NPs) and the approaches that are used to label exosomes with the NPs; specialIntscript the applications of exosomes labeled with nanoparticles in vitro and in vivo; specialIntscript the labeling strategy for exosomes identification and cancer detection.

Here, we demonstrated that natural magnetic nanoparticles (nMNP) from magnetotactic bacteria can serve as photoacoustic high-contrast agents for single cell analysis. The main benefits of nMNP include biocompatibility and relatively low laser fluence for photoacoustic detection. These features together with safety of photoacoustics provide potential for clinical translation. Further decoration of nMNP with NIR-absorbing gold nanorods provided hybrid nanoparticles with strong NIR absorption and plasmonic effects for cancer cell theranostics. In studies in vivo, we showed that circulating tumor cells labeled with bioinspired hybrids generated transient ultrasharp photoacoustic resonances as the basis for new super-resolution photoacoustic flow cytometry in vivo.

Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC). Here, we present a procedure to create a nanostructural graphene-platinum(Gr Pt) composite containing a small amount(5.3 wt%) of platinum nanoparticles coated with at least four layers of graphene. The composite, as Gr Pt ink, was deposited on a glassy carbon electrode and its electrocatalytic activity in a methanol oxidation reaction(MOR) was evaluated in a 1 M CH 3 OH/1 M Na OH solution. The results indicated an enhanced catalytic performance of Gr Pt towards MOR in alkaline media compared with the Pt/C material. Electron energy-loss spectroscopy and X-ray photoelectron spectroscopy(recorded before and after the electrochemical assays) were employed to analyze the changes in the chemical composition of the nanomaterial and to explain the transformations that took place at the electrode surface.Our findings suggest that growing of graphene on platinum nanoparticles improve the catalytic performance of platinum-graphene composites towards MOR in alkaline media.

Cadmium oxide nanoparticles (CdO NPs) are among some of the most studied and industrially used metal oxide NPs. They have been widely used for industrial application, such as paint pigments and electronic devices, and medical therapeutics. With increasing use of CdO NPs and concerns for their potential adverse effects on the environment and public health, evaluation of the cytotoxicity and genotoxicity of CdO NPs becomes very important. To date, there is a limited understanding of the potential hazard brought by CdO NPs and a lack of information and research, particularly on the genotoxicity assessment of these NPs. In this study, 10 nm CdO core-PEG stabilized NPs were synthesized, characterized and used for evaluation of CdO NPs' cytotoxicity and genotoxicity. Release of cadmium ions (Cd+2) from the CdO NPs in cell culture medium, cellular uptake of the NPs, and the endotoxin content of the particles were measured prior to the toxicity assays. Cytotoxicity was evaluated using the MTS assay, ATP content detection assay, and LDH assay. Genotoxicity was assessed using the Ames test, Comet assay, micronucleus assay, and mouse lymphoma assay. The cytotoxicity of cadmium chloride (CdCl2) was also evaluated along with that of the CdO NPs. The results showed that endotoxin levels within the CdO NPs were below the limit of detection. CdO NPs induced concentration-dependent cytotoxicity in TK6 and HepG2 cells with the MTS, ATP and LDH assays. Although the genotoxicity of CdO NPs was negative in the Ames test, positive results were obtained with the micronucleus, Comet, and mouse lymphoma assays. The negative response of CdO NPs with the Ames test may be the result of unsuitability of the assay for measuring NPs, while the positive responses from other genotoxicity assays suggest that CdO NPs can induce chromosomal damage, single or double strand breaks in DNA, and mutations. The toxicity of the CdO NPs results from the NPs themselves and not from the released Cd+2, because the ions released from the NPs were minimal. These results demonstrate that CdO NPs are cytotoxic and genotoxic and provide new insights into risk assessment of CdO NPs for human exposure and environmental protection.

The use of graphene for biomedical and other applications involving humans is growing and shows practical promise. However, quantifying the graphitic nanomaterials that interact with cells and assessing any corresponding cellular response is extremely challenging. Here, we report an effective approach to quantify graphene interacting with single cells that utilizes combined multimodal-Raman and photoacoustic spectroscopy. This approach correlates the spectroscopic signature of graphene with the measurement of its mass using a quartz crystal microbalance resonator. Using this technique, we demonstrate single cell noninvasive quantification and multidimensional mapping of graphene with a detection limit of as low as 200 femtograms. Our investigation also revealed previously unseen graphene-induced changes in surface receptor expression in dendritic cells of the immune system. This tool integrates high-sensitivity real-time detection and monitoring of nanoscale materials inside single cells with the measurement of induced simultaneous biological cell responses, providing a powerful method to study the impact of nanomaterials on living systems and as a result, the toxicology of nanoscale materials.

Graphene materials are widely used in the area of dopamine (DA) detection, but, in spite of the extensive work and the good reported results, the development of commercial graphene-based sensors for DA detection is still challenging. Actually, a lot of studies related to dopamine detection are conducted only for the development of new graphene materials, but the processes and transformations occurred at graphene electrode surface are not considered. In this work, the capacity of a nanocomposite, based on graphene and gold, platinum nanoparticles, to adsorb dopamine and the changes occurred during the DA electrooxidation process were investigated by electrochemistry, Raman spectroscopy and DFT methods. These studies were realized in the absence and the presence of two interfering agents, ascorbic (AA) and uric (UA) acids. Different molecular structures have been found for the species adsorbed on the graphene surface, before and after the electrooxidation process. The DA current density increased in the presence of AA even if neither the diffusion process nor the homogeneous catalysis were involved. The DA detection in the presence of UA appears to be influenced by larger adducts formed at the graphene surface. The DQ presence on the graphene surface was revealed when the procedure involved an electrochemical treatment with DA free in solution, more than five DPVs measurements and higher levels of DA concentration. The Raman investigations of the graphene-based electrodes indicated that the shifts of D frequency from graphene can be easily correlated with the electronic properties of adducts that have been adsorbed to the graphene surface (red shift for a graphene - electron-rich system interaction and a blue shift for graphene – electron-deficient adduct interaction). These results should be taken into consideration in the DA detection procedures or to the stategies to minimise the electrochemical fouling of DA when the graphene composites are used for electrode preparation.

Reduced graphene oxide (rGO) decorated with Fe doped SnO2 nanoparticles were fabricated via the electrostatic interaction between positively charged modified Fe-doped SnO2 oxide and negatively charged graphene oxide (GO) in the presence of poly(allylamine) hydrochloride (PAH). The decoration of rGO layers with SnO2:Fe nanoparticles was highlited by TEM microsopy. For composite sample the diffraction patterns coincide well with those of SnO2:Fe nanoparticles. The reduction of graphene oxide was evidenced using XRD and FT-IR spectroscopy. The formation of SnO2:Fe-PAH-graphene composites was confirmed by FT-IR, Raman and EPR spectroscopy. Sensitivity tests for relative humidity (RH) measurements were carried out at five different concentrations of humid air at room temperature. The prepared composite sensor exhibited a higher sensing response as compared with Fe:SnO2 nanoparticles. (C) 2017 Elsevier B.V. All rights reserved.

Raman spectroscopy and surface-enhanced raman scattering (SERS) have the potential to improve the detection and monitoring of various diseases, particularly cancer, with or without the support of multifunctional active nanosystems. This review is focused on the recent advances that have made Raman a major tool for treatment guidance for surgical tumor resection or for analytical monitoring of various therapies, such as photodynamic therapy, photothermal therapy, and drug delivery. The potential of Raman spectroscopy and nanosytems to further improve cancer treatments is also discussed.

Optical techniques, including Raman, photothermal and photoacoustic microscopy and spectroscopy, have been intensively explored for the sensitive and accurate detection of various diseases. Rapid advances in lasers, photodetectors, and nanotechnology have led to the development of Raman spectroscopy, particularly surface-enhanced Raman scattering (SERS), as a promising imaging modality that can help diagnose many diseases. This review focuses on the major recent advances in Raman spectroscopy and SERS-enhancing contrast nanoagents, as well as their potential to transition from a proof-of-concept approach to a cancer detection tool in vitro and in vivo.

The purpose of the present study is to analyze the effect of the new nanofiller type graphene-gold nanoparticles on the surface structure and surface properties of some dental nanocomposites based on BisGMA/triethyleneglicol dimethacrylate matrix. Materials used in our study were three experimental nanocomposites, two of them based on graphene-gold nanoparticles as filler of different percent. As reference material, a commercial dental nanocomposite product named Herculite XRV Ultra was used. FTIR-ATR spectroscopy was used to determine the residual double bonds and the degree of conversion (DC) after 1 and 21days of immersion in distilled water at 37 degrees C. The difference in DC between the experimental materials was statistically analyzed by one tail, paired Student's t-Tests, using Graph Pod. Surface properties were evaluated through surface free energy using contact angle measurement while roughness and topography was assessed using Atomic Force Microscopy (AFM). To determine the amount of filler particles and thermal behavior of organic matrix, the nanocomposites were investigated by thermal analysis. According to the experimental results, the dental nanocomposites with highest percent in graphene-gold nanoparticles present a better value for the surface free energy. AFM investigations reveal differences in the term of roughness properties and suggest that in order to improve the surface properties is necessary to use a higher percent of graphene-gold nanoparticles as filler. The degradation process of major nanocomposites constituents is observed at temperatures between 240 and 620 degrees C. Entire results sustain this, but the future studies in order to evaluate the biological properties of the experimental nanocomposites will be made.

We present the synthesis of core–shell nanostructural materials with multi-component architectures based on TiO2 and graphitic layers. The composites have been synthesized by chemical vapor deposition with methane as the carbon source, for 5, 10, 30 and 45min. The final products were characterized by a combination of analytical approaches which include: electron microscopy, Raman, FT-IR and UV–vis spectroscopy as well as thermogravimetric analysis. The amount of graphene shells covering the TiO2 surfaces was found to vary linearly with the reaction time. Furthermore, the compounds were shown to have excellent stability and photocatalytic activity towards the UV degradation of rhodamine (RhB) dye solution at room temperature. These composites could have major applications in the area of environmental cleaning of various pollutants, electrochemistry or nanomedicine.

Non-covalently iron-porphyrin functionalized N-doped graphene shows a higher peroxidase-like activity than its building blocks alone.

Noroviruses (NoV) have enhanced tropism for the gastrointestinal (GI) tract and are the major cause of nonbacterial gastroenteritis in humans. Titanium dioxide (TiO2) nanoparticles (NPs) used as food additives, dietary supplements, and cosmetics accumulate in the GI tract. We investigated the effect anatase TiO2 NPs on NoV replication and host response during virus infection, using murine norovirus (MNV-1) infection of RAW 264.7 macrophages. Pretreatment with 20 μg/ml anatase NPs significantly reduced the viability of macrophages alone or during virus infection, but did not alter virus replication. In contrast, pre-incubation with 2 μg/ml anatase NPs reduced virus replication fivefold at 48 h. The presence of anatase NPs during MNV-1 infection evoked a pro-inflammatory response, as measured by a significant increase in expression of cytokines, including IL-6, IFN-γ, TNFα and the TGFβ1. No genotoxic insults due to anatase TiO2 NPs alone or to their presence during MNV-1 infection were detected. This study highlights important safety considerations related to NP exposure of the GI tract in individuals infected with noroviruses or other foodborne viruses.

A new method for the preparation of HKUST-1 using a microwave-assisted non-solvothermal synthesis is presented. The influence of the reaction parameters (concentration of reactant mixtures, solvent, temperature, reaction time and microwave power) on the material's textural properties and yields has been investigated and the synthetic method was optimized. By exposing the reaction mixture to microwaves for up to 10 minutes HKUST-1 with a surface area and pore volume close to the theoretical values and a yield of about 70% was obtained. In addition, yields could reach around 90% if the product formed in the mother liquor is counted.

This study brings for the first time novel knowledge about the synthesis by catalytic chemical vapor deposition with induction heating of graphene-bimetallic nanoparticle composites (Gr-AuCu and Gr-AgCu) and their morphological and structural characterization by transmission electron microscopy, Raman spectroscopy, and x-ray powder diffraction. Gold electrodes modified with the obtained materials exhibit an enhanced electro-catalytic effect towards one of the most encountered estrogenic disruptive chemicals, bisphenol A (BPA). The BPA behavior in varying pH solutions was investigated using the electrochemical quartz crystal microbalance, which allowed the accurate determination of the number of molecules involved in the oxidation process. The modified electrodes promote the oxidation of BPA at significantly lower potentials (0.66 V) compared to bare gold (0.78 V). In addition, the peak current density recorded with such electrodes greatly exceeded that obtained with bare gold (e.g. one order of magnitude larger, for a Au/Gr-AgCu electrode). The two modified electrodes have low detection limits, of 1.31 × 10-6 M and 1.91 × 10-6 M for Au/Gr-AgCu and Au/Gr-AuCu, respectively. The bare gold electrode has a higher detection limit of 5.1 × 10-6 M. The effect of interfering species (e.g. catechol and 3-nitrophenol) was also investigated. Their presence influenced not only the BPA peak potential, but also the peak current. With both modified electrodes, no peak currents were recorded below 3 × 10-5 M BPA.

A simple and efficient approach for graphene production by electrochemical exfoliation of graphite rods in acidic solutions.