A novel nano-anti-malarial induces redox damage and elicits cytokine response to the parasite.

Emergence and spread of resistant parasites to the newest chemotherapeutic anti-malarial agents are the biggest challenges against malaria control programs. Therefore, developing a novel effective treatment to reduce the overgrowing burden of multidrug resistant malaria is a pressing need. Herein, we have developed a biocompatible and biodegradable, non-toxic chitosan-tripolyphosphate-chloroquine (CS-TPP CQ) nanoparticle. CS-TPP CQ nanoparticles effectively kill the parasite through redox generation and induction of the pro- and anti-inflammatory cytokines in both sensitive and resistant parasite in vitro. The in vitro observations showed a strong inhibitory effect (p < 0.01) on pro-inflammatory cytokines more specifically on TNF-α and IFN-γ whereas CS-TPP CQ nanoparticles significantly elevated the anti-inflammatory cytokines- IL-10 and TGF-ß. In addition, CS-TPP CQ nanoparticle significantly increased NO generation (p < 0.01) and altered the GSH/GSSG ratio 72 h after parasite co-culture with peripheral blood mononuclear cells culminating in the free radical induced parasite killing. CS-TPP CQ nanoparticle had an effective dose of 100 ng/ml against CQ-sensitive parasite lines (p < 0.001) whereas effective dose against CQ-resistant parasite line was 200 ng/ml CS-TPP CQ with an effective duration of 72 h (p < 0.001). Our studies suggest that CS-TPP CQ nanoparticle has a potential to modulate the pro- and anti-inflammatory responses, and to trigger the redox-mediated parasite killing. It can be a novel nano-based futuristic approach towards malaria control.

Pt decorated MoS2 nanoflakes for ultrasensitive resistive humidity sensor.

In this work, we report the fabrication of a low power, humidity sensor where platinum nanoparticles (NPs) decorated few-layered molybdenum disulphide (MoS2) nanoflakes have been used as the sensing layer. A mixed solvent was used to exfoliate the nanoflakes from the bulk powder. Then the Pt/MoS2 composites were prepared by reducing Pt NPs from chloroplatinic acid hexahydrate using a novel reduction technique using sulphide salt. The successful reduction and composite preparation were confirmed using various material characterization tools like scanning electron microscopy, atomic force microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy and UV-visible spectroscopy. The humidity sensors were prepared by drop-coating the Pt-decorated MoS2 on gold interdigitated electrodes and then exposed to various levels of relative humidity (RH). Composites with different weight ratios of Pt were tested and the best response was shown by the Pt/MoS2 (0.25:1) sample with a record high response of ∼4000 times at 85% RH. The response and recovery times were ∼92 s and ∼154 s respectively with repeatable behaviour. The sensor performance was found to be stable when tested over a few months. The underlying sensing mechanisms along with detailed characterization of the various composites have been discussed.

Sol-gel synthesis of cubic titanium dioxide nanoparticle using poly(ethylene glycol) as a capping agent: voltammetric simultaneous determination of uric acid and guanine.

Titanium dioxide nanoparticles (NPs) were synthesized by a sol-gel method from hexafluorotitanic acid using poly(ethylene glycol) as a capping agent. The crystal structure and morphology of the NPs were characterized by X-ray diffraction, FESEM, and TEM. The NPs were used to modify a graphite paste electrode for simultaneous determination of uric acid (UA) and guanine (GU). The effect of calcination temperature on crystal structure and electrocatalytic activity was investigated. The electrochemical responses to UA and GU at bare GP, TiO2-350/GP, and TiO2-600/GP electrodes were compared. The DPV oxidation peaks of UA and GU were found to be strongest at around 304 and 673 mV, respectively, against Ag/AgCl reference electrode, and this are well separated for effective simultaneous determination. UA and GU can be simultaneously determined by this method. Response is linear within the range 0.1-500 µM and 0.1-40 µM for UA and GU, respectively. The detection limits are 70 nM for UA and 50 nM for GU (at an S/N  ratio of 3). The TiO2-600/GP electrode showed excellent analytical performance when analyzing spiked urine and serum samples. Graphical abstract A graphical representation of cubic TiO2 nanoparticle formation during hydrolysis through sol-gel process.

In vitro dose and duration dependent approaches for the assessment of ameliorative effects of nanoconjugated vancomycin against Staphylococcus aureus infection induced oxidative stress in murine peritoneal macrophages.

AIMS: The present study was aimed to evaluate the in vitro ameliorative effect of nanoconjugated vancomycin (NV) against vancomycin sensitive and resistant strains of Staphylococcus aureus infection-induced oxidative stress in murine peritoneal macrophage. METHODS: Peritoneal macrophages from mice were treated with VSSA and VRSA (5 × 10(6) CFU/mL), VSSA + NV (5-250 µg/ml) and VRSA + NV (5-250 µg/ml) for 18 h, having 3 h interval in culture media; and the superoxide anion generation, lipid peroxidation, protein oxidation, antioxidant enzymes status and glutathione enzymes activity were monitored. RESULTS: The significantly increased free radical generation, lipid peroxidation, protein carbonyls and oxidized glutathione levels were observed in VSSA and VRSA treated group as compared to control group; where as reduced glutathione level, antioxidant enzymes status and glutathione dependent enzymes were decreased significantly. All these changes come near to control in NV treated group in a dose and duration dependent fashion. Among the different doses and duration intervals of NV, maximum ameliorative effect was observed by 100 µg/ml for 12 h treatment which does not produce any damage to the cell. CONCLUSIONS: These findings suggest the potential use and beneficial role of nanoconjugated vancomycin as a modulator of S. aureus infection-induced cellular damage in murine peritoneal macrophage.

Interplay between autophagy and apoptosis mediated by copper oxide nanoparticles in human breast cancer cells MCF7.

BACKGROUND: Metal oxide nanoparticles are well known to generate oxidative stress and deregulate normal cellular activities. Among these, transition metals copper oxide nanoparticles (CuO NPs) are more compelling than others and able to modulate different cellular responses. METHODS: In this work, we have synthesized and characterized CuO NPs by various biophysical methods. These CuO NPs (~30nm) induce autophagy in human breast cancer cell line, MCF7 in a time- and dose-dependent manner. Cellular autophagy was tested by MDC staining, induction of green fluorescent protein-light chain 3 (GFP-LC3B) foci by confocal microscopy, transfection of pBABE-puro mCherry-EGFP-LC3B plasmid and Western blotting of autophagy marker proteins LC3B, beclin1 and ATG5. Further, inhibition of autophagy by 3-MA decreased LD50 doses of CuO NPs. Such cell death was associated with the induction of apoptosis as revealed by FACS analysis, cleavage of PARP, de-phosphorylation of Bad and increased cleavage product of caspase 3. siRNA mediated inhibition of autophagy related gene beclin1 also demonstrated similar results. Finally induction of apoptosis by 3-MA in CuO NP treated cells was observed by TEM. RESULTS: This study indicates that CuO NPs are a potent inducer of autophagy which may be a cellular defense against the CuO NP mediated toxicity and inhibition of autophagy switches the cellular response into apoptosis. CONCLUSIONS: A combination of CuO NPs with the autophagy inhibitor is essential to induce apoptosis in breast cancer cells. GENERAL SIGNIFICANCE: CuO NP induced autophagy is a survival strategy of MCF7 cells and inhibition of autophagy renders cellular fate to apoptosis.

Phosphonomethyl iminodiacetic acid-conjugated cobalt oxide nanoparticles liberate Co(++) ion-induced stress associated activation of TNF-α/p38 MAPK/caspase 8-caspase 3 signaling in human leukemia cells.

The aim of this work is to understand the potential health effects of metal nanoparticles by exposing human leukemic cell lines (jurkat, K562 and KG1A cells) to nanosize phosphonomethyl iminodiacetic acid coated cobalt oxide (PMIDA-CoO) NPs. The synthesized PMIDA-CoO NPs were characterized by XRD, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. Our results showed that exposure of leukemic cell lines to PMIDA-CoO NPs caused reactive oxygen species (ROS) generation by increasing the concentration of free Co(++) ions in cancer microenvironment. But at physiological pH, PMIDA-CoO liberates little amount of Co(++) ions into media and exerts lower toxicity to normal cells up to a certain dose. PMIDA-CoO NPs caused DNA damage in leukemic cell lines, which was reflected by an increase in apoptosis of jurkat, KG-1A and K562 cells. PMIDA-CoO NPs induced apoptosis by increasing pro-inflammatory cytokines, primarily TNF-α. The in vivo study shows that PMIDA-CoO NPs were efficiently killed DLA cells. These findings have important implications for understanding the potential anticancer property induced by surface-modified cobalt oxide nanoparticles.

Cobalt oxide nanoparticles induced oxidative stress linked to activation of TNF-α/caspase-8/p38-MAPK signaling in human leukemia cells.

The purpose of this study was to determine the intracellular signaling transduction pathways involved in oxidative stress induced by nanoparticles in cancer cells. Activation of reactive oxygen species (ROS) has some therapeutic benefits in arresting the growth of cancer cells. Cobalt oxide nanoparticles (CoO NPs) are an interesting compound for oxidative cancer therapy. Our results showed that CoO NPs elicited a significant (P <0.05) amount of ROS in cancer cells. Co-treatment with N-aceyltine cystine (an inhibitor of ROS) had a protective role in cancer cell death induced by CoO NPs. In cultured cells, the elevated level of tumor necrosis factor-alpha (TNF-α) was noted after CoO NPs treatment. This TNF-α persuaded activation of caspase-8 followed by phosphorylation of p38 mitogen-activated protein kinase and induced cell death. This study showed that CoO NPs induced oxidative stress and activated the signaling pathway of TNF-α-Caspase-8-p38-Caspase-3 to cancer cells.

Chitosan-modified cobalt oxide nanoparticles stimulate TNF-α-mediated apoptosis in human leukemic cells.

The objective of this study was to develop chitosan-based delivery of cobalt oxide nanoparticles to human leukemic cells and investigate their specific induction of apoptosis. The physicochemical properties of the chitosan-coated cobalt oxide nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier transform infrared spectroscopy. The solubility of chitosan-coated cobalt oxide nanoparticles was higher at acidic pH, which helps to release more cobalt ions into the medium. Chitosan-coated cobalt oxide nanoparticles showed good compatibility with normal cells. However, our results showed that exposure of leukemic cells (Jurkat cells) to chitosan-coated cobalt oxide nanoparticles caused an increase in reactive oxygen species generation that was abolished by pretreatment of cells with the reactive oxygen species scavenger N-acetyl-L-cysteine. The apoptosis of Jurkat cells was confirmed by flow-cytometric analysis. Induction of TNF-α secretion was observed from stimulation of Jurkat cells with chitosan-coated cobalt oxide nanoparticles. We also tested the role of TNF-α in the induction of Jurkat cell death in the presence of TNF-α and caspase inhibitors. Treatment of leukemic cells with a blocker had a greater effect on cancer cell viability. From our findings, oxidative stress and caspase activation are involved in cancer cell death induced by chitosan-coated cobalt oxide nanoparticles.

Anticancer and immunostimulatory role of encapsulated tumor antigen containing cobalt oxide nanoparticles.

The purpose of this study is to evaluate the prospect of using surface modified cobalt oxide(CoO) nanoparticles as carriers of cancerantigens to human macrophages. N-Phosnomethyliminodiacetic acid (PMIDA) was used for surface modification to overcome the toxic effect of CoO nanoparticles. Here, the phosphonate group of the PMIDA acts as a surface-anchoring agent and the remaining -COOH groups bind nonspecifically with tumor associated antigens. This modification allows the conjugation of human oral carcinoma (KB) cell lysate (CL) as an antigen with PMIDA coated CoO nanoparticles (CL-PMIDA-CoO). Particle characterization was performed by dynamic light scattering, atomic force microscopy, and scanning electron microscopy studies. Fourier transform IR spectroscopy was used to investigate conjugation of the protein with nanoparticles. Protein encapsulation was confirmed by protein gel electrophoresis. Active uptake of antigen-conjugated nanoparticles by macrophages was confirmed by fluorescence microscopy. The antitumor activity of the nanocomplex pulsed macrophages was investigated on a human oral carcinoma cell line (KB) in vitro. The modified nanocomplexes upregulate IFN-γ and TNF-α and induce an anticancer immune response by activating macrophages. The use of TNF-α inhibitor confirmed the ability of the CL-PMIDA-CoO nanocomplex to stimulate TNF-α mediated immunostimulation. CL-PMIDA-CoO nanoparticles efficiently increased the CD4(+) population. Thus, our findings provide insight into the use of PMIDA coated CoO nanoparticles as antigen delivery vehicles.

A simple chemical reduction approach to dope ß-FeSi2 with boron and its comprehensive characterization.

ß-FeSi2 has been doped with Boron via a novel and cost-effective chemical reduction of the glassy phase of [(Fe2O3 + 4SiO2 + B2O3 + FeBO3 + Fe2SiO4)] using Mg metal at 800 °C. Doped ß-FeSi2 has been investigated via extensive characterization and detailed analysis using first-principles calculations. The reduction in the d-spacing as can be observed from the XRD peak shift as well as the blue shift of the ß-Raman line along with the right shift of Si and Fe 2p peaks indicate the B doping. The Hall investigation basically demonstrates p-type conductivity. Hall parameters were also analyzed using thermal mobility and dual-band model. The temperature profile of RH demonstrates the contribution of shallow acceptor levels at low temperatures, whereas the deep acceptor level contributes at high temperatures. Dual-band investigation reveals a substantial increase in the Hall concentration with B doping due to the cumulative contribution of both deep and shallow acceptor levels. The low-temperature mobility profile exhibits phonon and ionized impurity scattering just above and below 75 K, respectively. Moreover, it demonstrates that holes in low-doped samples can be transported more easily than at higher B doping. From density functional theory (DFT) calculations, the origin of the dual-band model has been validated from the electronic structure of ß-FeSi2. Further, the effects of Si and Fe vacancies and B doping on the electronic structure of ß-FeSi2 have also been demonstrated. The charge transfer to the system due to B doping has indicated that an increase in doping leads to higher p-type characteristics.

Staphylococcus aureus infection induced redox signaling and DNA fragmentation in T-lymphocytes: possible ameliorative role of nanoconjugated vancomycin.

Staphylococcus aureus is most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Vancomycin sensitive and resistant S. aureus infection causes oxidative stress in neutrophils and lymphocytes. Lymphocyte is an important immune cell. The immune cells use reactive oxygen species (ROS) for carrying out their normal functions while an excess amount of ROS can attack cellular components that lead to cell damage. The aim of the present study was to test the protective role of nanoconjugated vancomycin against Vancomycin Sensitive S. aureus (VSSA) and Vancomycin Resistant S. aureus (VRSA) infection induced oxidative stress in T-lymphocytes. VSSA and VRSA infection were developed in Swiss mice by intraperitoneal injection of 5 × 10(6) CFU/ml bacterial solutions. Nanoconjugated vancomycin was treated to VSSA and VRSA infected mice at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively for successive 10 days. Vancomycin was treated to VSSA and VRSA infected mice at similar dose, respectively, for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of nitrite generation, lipid peroxidation, protein oxidation, oxidized glutathione level, DNA fragmentation, and decreases the level of reduced glutathione, antioxidant enzyme status, glutathione dependent enzymes as compared to control group; which were increased or decreased significantly near to normal in T-lymphocytes of nanoconjugated vancomycin treated group. These finding suggests the potential use and beneficial protective role of nanoconjugated vancomycin against VSSA and VRSA infection induced oxidative stress in T-lymphocytes.

"Clickable", trifunctional magnetite nanoparticles and their chemoselective biofunctionalization.

A multifunctional iron oxide based nanoformulation for combined cancer-targeted therapy and multimodal imaging has been meticulously designed and synthesized using a chemoselective ligation approach. Novel superparamagnetic magnetite nanoparticles simultaneously functionalized with amine, carboxyl, and azide groups were fabricated through a sequence of stoichiometrically controllable partial succinylation and Cu (II) catalyzed diazo transfer on the reactive amine termini of 2-aminoethylphosphonate grafted magnetite nanoparticles (MNPs). Functional moieties associated with MNP surface were chemoselectively conjugated with rhodamine B isothiocyanate (RITC), propargyl folate (FA), and paclitaxel (PTX) via tandem nucleophic addition of amine to isothithiocyanates, Cu (I) catalyzed azide--alkyne click chemistry and carbodiimide-promoted esterification. An extensive in vitro study established that the bioactives chemoselectively appended to the magnetite core bequeathed multifunctionality to the nanoparticles without any loss of activity of the functional molecules. Multifunctional nanoparticles, developed in the course of the study, could selectively target and induce apoptosis to folate-receptor (FR) overexpressing cancer cells with enhanced efficacy as compared to the free drug. In addition, the dual optical and magnetic properties of the synthesized nanoparticles aided in the real-time tracking of their intracellular pathways also as apoptotic events through dual fluorescence and MR-based imaging.

In vitro antibacterial activity of nanoconjugated vancomycin against plasmid mediated intraspecies and interspecies transfer of vancomycin resistance.

BACKGROUND: The aim of the present study was to observe the plasmid mediated intraspecies and interspecies transfer of vancomycin resistance, and possible antibacterial activity of nanoconjugated vancomycin against such resistant. METHODS: Plasmids were isolated from a chosen vancomycin resistant Staphylococcus aureus strain (MMC-17). The obtained 890 bp plasmid was then transferred to vancomycin sensitive S. aureus (MMC-6) and Escherichia coli (RGK 26) strains. RESULTS: The vancomycin sensitive S. aureus and E. coli developed vancomycin resistance. Plasmid analysis of the transformed MMC-6 and RGK 26 revealed that it contains 890 bp plasmid corresponding to the donor S. aureus, which may harbor the vanA gene. Nanoconjugated vancomycin shows its efficient drug action through transport of vancomycin into transformed MMC-6 and RGK 26. CONCLUSIONS: Plasmid mediated intraspecies and interspecies transfer of vancomycin resistance is accomplished by the vanA gene. Nanoconjugated vancomycin shows effective drug delivery in plasmid mediated vancomycin resistance in S. aureus and E. coli.

Maleic and L-tartaric acids as new anti-sprouting agents for potatoes during storage in comparison to other efficient sprout suppressants.

Inhibiting sprouting of potatoes is an interesting subject needed for potato storage and industry. Sprouting degrades the quality of tuber along with releasing α-solanine and α-chaconine, which are harmful for health. Sprout suppressants, available in the market, are either costly or toxic to both health and environment. So, there is a need for developing countries to explore new sprouting suppressant compound which is cheap, non-toxic and reasonably efficient in comparison to commercial ones. We have established that simple maleic acid and L-tartaric acid are effective sprout suppressing agents. Both can hinder sprouting up to 6 weeks and 4 weeks post treatment respectively at room temperature in dark. These do not affect the quality parameters, retain the moisture content and maintain the stout appearance of the tubers along the total storage period. Thus maleic acid and L-tartaric acid would qualify as alternative, cheap, efficient sprout suppressant for potato storage and processing.

Substitutional Doping of MoS2 for Superior Gas-Sensing Applications: A Proof of Concept.

Two-dimensional layered materials (like MoS2 and WS2) those are being used as sensing layers in chemoresistive gas sensors suffer from poor sensitivity and selectivity. Mere surface functionalization (decorating of material surface) with metal nanoparticles (NPs) might not improve the sensor performance significantly. In this respect, doping of the layered material can play a significant role. Here, we report a simple yet effective substitutional doping technique to dope MoS2 with noble metals. Through various material characterization techniques like X-ray diffraction, scanning tunneling spectroscopy images, and selected area electron diffraction pattern, we were able to put forward the difference between surface decoration and substitutional doping by Au at S-vacancy sites of MoS2. Lattice strain was found to exist in the Au-doped MoS2 samples, while being absent in the Au NP-decorated samples. Surface chemistry studies performed using X-ray photoelectron spectroscopy showed a shift of Mo 3d peaks to lower binding energies, thus realizing p-type doping due to Au. The blue shift of the peaks as observed in Raman spectroscopy further confirmed the p-type doping. We found that gold-doped MoS2 was more sensitive and selective toward ammonia (with a response of 150% for 500 ppm of ammonia at 90 °C) as compared to gold NP-decorated MoS2. The advantages of substitutional doping and the gas-sensing mechanism were also explained by the density functional theory study. From the first principles study, it was found that the adsorption of Au atoms on the S-vacancy site of a monolayer of the MoS2 sheet was thermodynamically favorable with the adsorption energy of 2.39 eV. We also successfully doped MoS2 with Pt using the same technique. It was found that Pt-doped MoS2 gives huge response toward humidity (60,000% at 80% relative humidity). Thus, various noble metal doping of MoS2 selectively improved the sensing response toward specific analytes. From this work, we believe that this method could also be useful to dope other layered nanomaterials to design gas sensors with improved selectivity.

Nanoconjugated vancomycin: new opportunities for the development of anti-VRSA agents.

More than 90% of Staphylococcus strains are resistant to penicillin. In 1961 S. aureus developed resistance to methicillin (MRSA), invalidating almost all antibiotics, including the most potent beta-lactams. Vancomycin, a glycopeptide antibiotic, was used for the treatment of MRSA in 1980. Vancomycin inhibits the bio-synthesis of peptidoglycan and the assembly of NAM-NAG-polypeptide into the growing peptidoglycan chain. Vancomycin resistant S. aureus (VRSA) first appeared in the USA in 2002. Folic acid tagged chitosan nanoparticles are used as Trojan horses to deliver vancomycin into bacterial cells. These nanoparticles are biocompatible and biodegradable semisynthetic polymers. These nanosized vehicles enhance the transport of vancomycin across epithelial surfaces and show its efficient drug action, which has been understood from studies of the minimum inhibitory concentration and minimum bactericidal concentration of nanoparticles of a chitosan derivative loaded with vancomycin. Tolerance values distinctly show that vancomycin loaded into nanoconjugate is very effective and has a strong bactericidal effect on VRSA.

Highly biocompatible and water-dispersible, amine functionalized magnetite nanoparticles, prepared by a low temperature, air-assisted polyol process: a new platform for bio-separation and diagnostics.

A low temperature polyol process, based on glycolaldehyde mediated partial reduction of FeCl(3).6H(2)O at 120 degrees C in the presence of sodium acetate as an alkali source and 2, 2(')-(ethylenedioxy)-bis-(ethylamine) as an electrostatic stabilizer has been used for the gram-scale preparation of biocompatible, water-dispersible, amine functionalized magnetite nanoparticles (MNPs) with an average diameter of 6 +/- 0.75 nm. With a reasonably high magnetization (37.8 e.m.u.) and amine groups on the outer surface of the nanoparticles, we demonstrated the magnetic separation and concentration implications of these ultrasmall particles in immunoassay. MRI studies indicated that these nanoparticles had the desired relaxivity for T(2) contrast enhancement in vivo. In vitro biocompatibility, cell uptake and MR imaging studies established that these nanoparticles were safe in clinical dosages and by virtue of their ultrasmall sizes and positively charged surfaces could be easily internalized by cancer cells. All these positive attributes make these functional nanoparticles a promising platform for further in vitro and in vivo evaluations.

In vitro evaluation of folic acid modified carboxymethyl chitosan nanoparticles loaded with doxorubicin for targeted delivery.

The development of smart targeted nanoparticle that can deliver drugs to direct cancer cells, introduces better efficacy and lower toxicity for treatment. We report the development and characterizations of pH-sensitive carboxymethyl chitosan modified folic acid nanoparticles and manifest their feasibility as an effective targeted drug delivery vehicle. The nanoparticles have been synthesized from carboxymethyl chitosan with covalently bonded bifunctional 2,2'-(ethylenedioxy)-bis-(ethylamine) (EDBE) through the conjugation with folic acid. The conjugation has been analyzed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The resultant nanoparticles with an average size less then 200 nm measured by dynamic light scattering and transmission electron microscopy. Confocal microscopy and flow cytometric analysis have revealed that folate-mediated targeting significantly enhances the cellular uptake of the nanoparticle and thus facilitates apoptosis of cancer cells (HeLa, B16F1). For the application of the nanoparticles as a drug carrier, Doxorubicin a potent anticancer drug has been loaded into the nanoparticles, with the drug loading amount and the drug release pattern observed.

Simultaneous voltammetric determination of Adrenaline and Tyrosine in real samples by neodymium oxide nanoparticles grafted graphene.

Nd2O3 nanoparticle grafted graphene nanocomposite (NOGG) was synthesized by sonochemical treatment of an ethanolic dispersion of Nd2O3 nanoparticle and graphene. All the synthesized materials were characterized by XRD, FESEM, TEM, and BET. The NOGG has a high specific surface area (272 m2g-1) with narrowly distributed pores with diameter centered at 2.8, 6.0 and 7.50 nm. A composite paste electrode of 1:1 (w/w) NOGG and graphite was showed better electrochemical properties. The NOGG/GP electrode showed all around better electrocatalytic activity towards Adrenaline (AD) and Tyrosine (TY) than TRG/GP and bare GP electrode. According to cyclic voltammograms, AD and TY oxidized irreversibly through adsorption control process. DPV peak currents were measured at 378 ±â€¯15 mV and 787 ±â€¯15 mV for determination AD and TY respectively using the NOGG/GP electrode as the peak intensities were highest at those potentials. Under the optimized experimental condition, the determination ranges for AD and TY showed two linear ranges, those were 0.1-5-130 µM and 0.1-3-120 µM, respectively. A detection limit of AD and TY was measured (m-LOD) to be 50 nM and 40 nM, respectively. The modified electrode was reproducible, selective, highly sensitive and also employed for analysis of AD and TY in biological and pharmaceutical samples with excellent recovery.

Biofunctionalized, phosphonate-grafted, ultrasmall iron oxide nanoparticles for combined targeted cancer therapy and multimodal imaging.

A novel, inexpensive biofunctionalization approach is adopted to develop a multimodal and theranostic nanoagent, which combines cancer-targeted magnetic resonance/optical imaging and pH-sensitive drug release into one system. This multifunctional nanosystem, based on an ultrasmall superparamagnetic iron oxide (USPIO) nanocore, is modified with a hydrophilic, biocompatible, and biodegradable coating of N-phosphonomethyl iminodiacetic acid (PMIDA). Using appropriate spacers, functional molecules, such as rhodamine B isothiocyanate, folic acid, and methotrexate, are coupled to the amine-derivatized USPIO-PMIDA support with the aim of endowing simultaneous targeting, imaging, and intracellular drug-delivering capability. For the first time, phosphonic acid chemistry is successfully exploited to develop a stealth, multifunctional nanoprobe that can selectively target, detect, and kill cancer cells overexpressing the folate receptor, while allowing real-time monitoring of tumor response to drug treatment through dual-modal fluorescence and magnetic resonance imaging.