Sample records for nanoparticles incorporating kaempferol

  1. Silver nanoparticles fluorescence enhancement effect for determination of nucleic acids with kaempferol–Al(III)

    Microsoft Academic Search

    Yinghua Cao; Xia Wu; Minqin Wang

    2011-01-01

    Nucleic acids can greatly enhance fluorescence intensity of the kaempferol (Km)–Al(III) system in the presence of silver nanoparticles (AgNPs). Based on this, a novel method for the determination of nucleic acids is proposed. Under studied conditions, there are linear relationships between the extent of fluorescence enhancement and the concentration of nucleic acids in the range of 5.0×10?9 to 2.0×10?6gmL?1 for

  2. Incorporation of polymeric nanoparticles into solid dosage forms

    Microsoft Academic Search

    Christoph Schmidt; Roland Bodmeier

    1999-01-01

    Besides parenteral delivery, polymeric nanoparticles have been used for oral drug delivery. In this study, model polymeric nanoparticles (aqueous colloidal polymer dispersions: Eudragit® RL 30D, L 30D, NE 30D, or Aquacoat®) with different physicochemical properties were incorporated into various solid dosage forms (granules, tablets, pellets or films). The compatibility of the nanoparticles with commonly used tabletting excipients and the redispersibility

  3. CCMR: Electrospun Fibers Incorporating pH-Sensitive Nanoparticles

    NSDL National Science Digital Library

    Buttaro, Larissa

    2009-08-15

    This research focuses on the incorporation of pH-sensitive nanoparticles into electrospun fibers to function as a sweat monitoring device. In order to determine how fiber size effects the relationship between nanoparticle dye intensity and pH value, the fibers were electrospun at three different speeds: 0.03 mL/hr, 0.3 mL/hr and 0.3 mL/min. These speeds produced fibers of approximately 1.3 ?m, 1.8 ?m, and 9.5 ?m in diameter, respectively. The research found that nanoparticles with smaller fibers are more sensitive to pH change than larger fibers.

  4. Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates

    PubMed Central

    Mei, Qinggang; Wang, Chun; Yuan, Weicheng

    2015-01-01

    Summary A strategy for selective mono-, di- and tri-O-methylation of kaempferol, predominantly on the basis of selective benzylation and controllable deacetylation of kaempferol acetates, was developed. From the selective deacetylation and benzylation of kaempferol tetraacetate (1), 3,4?,5,-tri-O-acetylkaempferol (2) and 7-O-benzyl-3,4?5,-tri-O-acetylkaempferol (8) were obtained, respectively. By controllable deacetylation and followed selective or direct methylation of these two intermediates, eight O-methylated kaempferols were prepared with 51–77% total yields from kaempferol. PMID:25815082

  5. Pluronic@Fe3O4 nanoparticles with robust incorporation of doxorubicin by thermo-responsiveness.

    PubMed

    Park, Shinyoung; Kim, Hye Sung; Kim, Woo Jin; Yoo, Hyuk Sang

    2012-03-15

    Doxorubicin was physically incorporated in magnetic nanoparticles by thermo-responsive manners. Magnetic nanoparticles were prepared by oxidizing ferric ions in ammonium solution. Thiolated Pluronic was synthesized by sequential modification of terminal hydroxyl groups of Pluronic to amine groups and thiol groups. Magnetic nanoparticles composed of iron oxide were surface-modified with thiolated Pluronic at different molar ratios of iron to thiol groups. Pluronic decoration on the magnetic nanoparticles was characterized by elemental analysis and transmission electron microscopy. Elemental analysis results on carbon atoms in the magnetic nanoparticles showed that the degree of Pluronic decoration was proportional to the feed ratio of thiolated Pluronic to iron oxide. Doxorubicin was incorporated to the magnetic nanoparticles thermo-responsive manners; a mixture of hydrophobized doxorubicin and the magnetic nanoparticles was incubated at 4°C and the temperature was subsequently increased to 37°C for thermally induced structural changes of the decorated Pluronic moieties. Doxorubicin-incorporated magnetic nanoparticles showed dramatic modulations of size distributions according to temperature changes, which was dependent on the degree of Pluronic decoration. Loading efficiency of doxorubicin was significantly affected by the number of decorated Pluronic on the magnetic nanoparticles; the higher Pluronic moieties the nanoparticles had, the higher loading efficiency they showed. Release profiles of doxorubicin from the nanoparticles showed that doxorubicin was liberated from the nanoparticles in response to reducing conditions of the release medium. Anti-cancer activities of the doxorubicin-incorporated nanoparticles were determined by a MTT-based cytotoxicity assay against A549 cell lines. Compared to native doxorubicin, the doxorubicin incorporated magnetites showed attenuated cytotoxicities due to slow release of doxorubicin from the carriers. Thus, thermally induced incorporation of anti-cancer drugs can be a novel method for multifunctional magnetic nanoparticles with imaging and anti-cancer treatments. PMID:22226875

  6. Kaempferol inhibits thrombosis and platelet activation.

    PubMed

    Choi, Jun-Hui; Park, Se-Eun; Kim, Sung-Jun; Kim, Seung

    2015-08-01

    The objectives of the present study were to investigate whether kaempferol affects pro-coagulant proteinase activity, fibrin clot formation, blood clot and thrombin (or collagen/epinephrine)-stimulated platelet activation, thrombosis, and coagulation in ICR (Imprinting Control Region) mice and SD (Sprague-Dawley) rats. Kaempferol significantly inhibited the enzymatic activities of thrombin and FXa by 68 ± 1.6% and 52 ± 2.4%, respectively. Kaempferol also inhibited fibrin polymer formation in turbidity. Microscopic analysis was performed using a fluorescent conjugate. Kaempferol completely attenuated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun N-terminal kinase (JNK) 1/2, and phosphoinositide 3-kinase (PI3K)/PKB (AKT) in thrombin-stimulated platelets and delayed aggregation time (clotting) by 34.6% in an assay of collagen/epinephrine-stimulated platelet activation. Moreover, kaempferol protected against thrombosis development in 3 animal models, including collagen/epinephrine- and thrombin-induced acute thromboembolism models and an FeCl3-induced carotid arterial thrombus model. The ex vivo anticoagulant effect of kaempferol was further confirmed in ICR mice. This study demonstrated that kaempferol may be clinically useful due to its ability to reduce or prevent thrombotic challenge. PMID:26073152

  7. Quantum dots incorporated magnetic nanoparticles for imaging colon carcinoma cells

    PubMed Central

    2013-01-01

    Background Engineered multifunctional nanoparticles (NPs) have made a tremendous impact on the biomedical sciences, with advances in imaging, sensing and bioseparation. In particular, the combination of optical and magnetic responses through a single particle system allows us to serve as novel multimodal molecular imaging contrast agents in clinical settings. Despite of essential medical imaging modalities and of significant clinical application, only few nanocomposites have been developed with dual imaging contrast. A new method for preparing quantum dots (QDs) incorporated magnetic nanoparticles (MNPs) based on layer-by-layer (LbL) self-assembly techniques have developed and used for cancer cells imaging. Methods Here, citrate - capped negatively charged Fe3O4 NPs were prepared and coated with positively - charged hexadecyltrimethyl ammonium bromide (CTAB). Then, thiol - capped negatively charged CdTe QDs were electrostatically bound with CTAB. Morphological, optical and magnetic properties of the fluorescent magnetic nanoparticles (FMNPs) were characterized. Prepared FMNPs were additionally conjugated with hCC49 antibodies fragment antigen binding (Fab) having binding affinity to sialylated sugar chain of TAG-72 region of LS174T cancer cells, which was prepared silkworm expression system, and then were used for imaging colon carcinoma cells. Results The prepared nanocomposites were magnetically responsive and fluorescent, simultaneously that are useful for efficient cellular imaging, optical sensing and magnetic separation. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size is around 50 nm in diameter with inner magnetic core and outer CdTe QDs core-shell structure. Cytotoxicity test of prepared FMNPs indicates high viability in Vero cells. NPs conjugated with anti cancer antibodies were successfully labeled on colon carcinoma cells (LS174) in vitro and showed significant specificity to target cells. Conclusion The present report demonstrates a simple synthesis of CdTe QDs-Fe3O4 NPs. The surface of the prepared FMNPs was enabled simple conjugation to monoclonal antibodies by electrostatic interaction. This property further extended their in vitro applications as cellular imaging contrast agents. Such labeling of cells with new fluorescent-magneto nanoprobes for living detection is of interest to various biomedical applications and has demonstrated the potential for future medical use. PMID:23957878

  8. Cisplatin-incorporated nanoparticles of poly(acrylic acid-co-methyl methacrylate) copolymer

    PubMed Central

    Lee, Kyung Dong; Jeong, Young-Il; Kim, Da Hye; Lim, Gyun-Taek; Choi, Ki-Choon

    2013-01-01

    Background Although cisplatin is extensively used in the clinical field, its intrinsic toxicity limits its clinical use. We investigated nanoparticle formations of poly(acrylic acid-co-methyl methacrylate) (PAA-MMA) incorporating cisplatin and their antitumor activity in vitro and in vivo. Methods Cisplatin-incorporated nanoparticles were prepared through the ion-complex formation between acrylic acid and cisplatin. The anticancer activity of cisplatin-incorporated nanoparticles was assessed with CT26 colorectal carcinoma cells. Results Cisplatin-incorporated nanoparticles have small particle sizes of less than 200 nm with spherical shapes. Drug content was increased according to the increase of the feeding amount of cisplatin and acrylic acid content in the copolymer. The higher acrylic acid content in the copolymer induced increase of particle size and decrease of zeta potential. Cisplatin-incorporated nanoparticles showed a similar growth-inhibitory effect against CT26 tumor cells in vitro. However, cisplatin-incorporated nanoparticles showed improved antitumor activity against an animal tumor xenograft model. Conclusion We suggest that PAA-MMA nanoparticles incorporating cisplatin are promising carriers for an antitumor drug-delivery system. PMID:23966778

  9. Chemical Dynamics in Energetic Materials Incorporating Aluminum Nanoparticles

    NASA Astrophysics Data System (ADS)

    Lewis, William K.; Harruff, Barbara A.; Fernando, K. A. Shiral; Smith, Marcus J.; Guliants, Elena A.; Bunker, Christopher E.

    2010-06-01

    Aluminum nanoparticles are widely considered attractive as fuels due to the high heat of reaction associated with their oxidation, and the potential for fast reaction due to their small size. However, the reaction dynamics can also be strongly influenced by the passivation layer that coats the reactive metal surface. Typically, this takes the form of a naturally-occurring oxide shell on the nanoparticle, but other passivation schemes are now available. We have recently developed a sonochemical synthesis procedure to produce aluminum nanoparticles capped with oleic acid. These nanoparticles have an aluminum metal core, some organic-provided oxide, and an organic shell. To investigate the effect of the passivation method on the chemical dynamics in energetic materials, we have studied samples consisting of a mixture of a metal nanoparticle fuel and an ammonium nitrate or ammonium perchlorate oxidizer. The metal fuel is either commercially available oxide-coated aluminum nanoparticles, or the oleic acid-capped nanoparticles. The energetic samples are ignited with an IR laser pulse. Following ignition, the chemical dynamics are studied using visible emission spectroscopy and mass spectrometry. Preliminary results suggest that our Al-oleic acid nanoparticles are able to react more rapidly than those that are conventionally passivated with a naturally-occurring oxide shell. K. A. S. Fernando, M. J. Smith, B. A. Harruff, W. K. Lewis, E. A. Guliants and C. E. Bunker J. Phys. Chem. C, 113, 500 (2009).

  10. Curcumin-incorporated albumin nanoparticles and its tumor image

    NASA Astrophysics Data System (ADS)

    Gong, Guangming; Pan, Qinqin; Wang, Kaikai; Wu, Rongchun; Sun, Yong; Lu, Ying

    2015-01-01

    Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)–curcumin (CCM) nanoparticles, in which ?-mercaptoethanol (?-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA–CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA–CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA–CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by ?-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes.

  11. Hybrid organic-inorganic monolithic enzymatic reactor with SBA-15 nanoparticles incorporated.

    PubMed

    Zhang, Zhaodi; Zhang, Lingyi; Zhang, Chenggong; Zhang, Weibing

    2014-02-01

    A novel enzymatic reactor was prepared by incorporating SBA-15 nanoparticles into hybrid organic-inorganic monolith and immobilizing trypsin with glutaraldehyde as bridging reagent. Preparation and operation conditions including nanoparticles percentage and residence time were optimized to improve the digestion efficiency. The digestion products were characterized by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) with sequence coverage of 50%, 93% and 71% for bovine serum albumin, myoglobin and cytochrome C, while consuming only about 19s in dynamic mode. Compared with enzymatic reactor without nanoparticles incorporated, the enzymatic reactor with SBA-15 nanoparticles embedded achieved higher digestion efficiency by introducing more trypsin, which was originated from combination of SBA-15 nanoparticles and hybrid organic-inorganic monolith. PMID:24401445

  12. Chemical Dynamics in Energetic Materials Incorporating Aluminum Nanoparticles

    Microsoft Academic Search

    William K. Lewis; Barbara A. Harruff; K. A. Shiral Fernando; Marcus J. Smith; Elena A. Guliants; Christopher E. Bunker

    2010-01-01

    Aluminum nanoparticles are widely considered attractive as fuels due to the high heat of reaction associated with their oxidation, and the potential for fast reaction due to their small size. However, the reaction dynamics can also be strongly influenced by the passivation layer that coats the reactive metal surface. Typically, this takes the form of a naturally-occurring oxide shell on

  13. Boehmite nanoparticles incorporated electrospun nylon-6 nanofiber web for new electret filter media

    Microsoft Academic Search

    Bong Yeol Yeom; Eunkyoung Shim; Behnam Pourdeyhimi

    2010-01-01

    Nylon-6 (PA6) nanofiber webs incorporated with boehmite nanoparticles as an electrostatic charging agent were electrospun\\u000a and their fiber morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).\\u000a SEM showed that the median fiber diameter of the PA6 nanofibers was 73 nm and boehmite nanoparticles had little effect on\\u000a the fiber diameter. The filtration performance of the

  14. Thermal conductivity measurement of organic solvents incorporated with silver nanoparticle using photothermal techniques

    NASA Astrophysics Data System (ADS)

    Shemeena Basheer, N.; Kumar, B. Rajesh; Kurian, Achamma; George, Sajan D.

    2015-02-01

    The present paper summarizes our recent work on heat transfer of nanofluid in different organic solvents determined using photothermal techniques. UV- Visible absorption spectrum shows an intense surface plasmon absorption peak at 427 nm. TEM indicates the presence of well dispersed silver nanoparticles having spherical morphology with particle size ranging from 10 to13 nm. The experimental results show that thermal conductivity of organic solvents increases with the incorporation of silver nanoparticles.

  15. Superparamagnetic iron oxide nanoparticles incorporated into silica nanoparticles by inelastic collision via ultrasonic field: Role of colloidal stability

    NASA Astrophysics Data System (ADS)

    Sodipo, Bashiru Kayode; Azlan, Abdul Aziz

    2015-04-01

    Superparamagnetic iron oxide nanoparticles (SPION)/Silica composite nanoparticles were prepared by ultrasonically irradiating colloidal suspension of silica and SPION mixture. Both silica and SPION were synthesized independently via co-precipitation and sol-gel method, respectively. Their mixtures were sonicated at different pH between 3 and 5. Electrophoresis measurement and other physicochemical analyses of the products demonstrate that at lower pH SPION was found incorporated into the silica. However, at pH greater than 4, SPION was unstable and unable to withstand the turbulence flow and shock wave from the ultrasonic field. Results suggest that the formation of the SPION/silica composite nanoparticles is strongly related to the inelastic collision induced by ultrasonic irradiation. More so, the formation the composite nanoparticles via the ultrasonic field are dependent on the zeta potential and colloidal stability of the particles.

  16. Incorporation of Metallic Nanoparticles into Conducting Polymer Actuator Films

    NASA Astrophysics Data System (ADS)

    Costa, Alexsandro Santos; Li, Kwong-Chi; Kilmartin, Paul A.; Travas-Sejdic, Jadranka

    2009-07-01

    Nanocomposites of conducting polymer films (CP) with metal nanoparticles have been prepared. Electropolymerization of pyrrole on stainless steel electrodes was undertaken galvanostatically until the thickness of the polypyrrole (PPy) film reached around 7.5 ?m, which is suitable for the future application of these films in micropumps and microvalves. Subsequently platinum nanoparticles were deposited from a solution of a platinum precursor (K2PtCl6) onto the PPy coated stainless steel electrodes by applying a potential of -0.1 V for between 3 and 15 s. The length of the deposition time led to significant differences in the morphology and size of the particles obtained. The actuation of the free standing films was studied by electrochemomechanical deformation measurements (ECMD) on strips of films cycled in NaPF6. Depending upon the test conditions, the strain rate and ultimate strain of films containing Pt nanoparticles could be increased by a factor of 2 or more compared to those of pristine PPy films.

  17. Optofluidics incorporating actively controlled micro- and nano-particles

    PubMed Central

    Kayani, Aminuddin A.; Khoshmanesh, Khashayar; Ward, Stephanie A.; Mitchell, Arnan; Kalantar-zadeh, Kourosh

    2012-01-01

    The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

  18. Kaempferol Downregulates Insulin-like Growth Factor-I Receptor and ErbB3 Signaling in HT-29 Human Colon Cancer Cells

    PubMed Central

    Lee, Hyun Sook; Cho, Han Jin; Kwon, Gyoo Taik; Park, Jung Han Yoon

    2014-01-01

    Background: Novel dietary agents for colon cancer prevention and therapy are desired. Kaempferol, a flavonol, has been reported to possess anticancer activity. However, little is known about the molecular mechanisms of the anticancer effects of kaempferol. The aim of this study was to determine the inhibitory effect of kaempferol on growth factor-induced proliferation and to elucidate its underlying mechanisms in the HT-29 human colon cancer cell line. Methods: To assess the effects of kaempferol and/or growth factors [insulin-like growth factor (IGF)-I and heregulin (HRG)-?], cells were cultured with or without 60 ?mol/L kaempferol and/or 10 nmol/L IGF-I or 20 ?g/L HRG-?. Cell proliferation, DNA synthesis, and apoptosis were determined by a cell viability assay, a [3H]thymidine incorporation assay, and Annexin-V staining, respectively. Western blotting, immunoprecipitation, and an in vitro kinase assay were conducted to evaluate expression and activation of various signaling molecules involved in the IGF-I receptor (IGF-IR) and ErbB3 signaling pathways. Results: IGF-I and HRG-? stimulated HT-29 cell growth but did not abrogate kaempferol-induced growth inhibition and apoptosis. Kaempferol reduced IGF-II secretion, HRG expression and phosphorylation of Akt and extracellular signal-regulated kinase (ERK)-1/2. Kaempferol reduced IGF-I- and HRG-?-induced phosphorylation of the IGF-IR and ErbB3, their association with p85, and phosphatidylinositol 3-kinase (PI3K) activity. Additionally, kaempferol inhibited IGF-I- and HRG-?-induced phosphorylation of Akt and ERK-1/2. Conclusions: The results demonstrate that kaempferol downregulates activation of PI3K/Akt and ERK-1/2 pathways by inhibiting IGF-IR and ErbB3 signaling in HT-29 cells. We suggest that kaempferol could be a useful chemopreventive agent against colon cancer. PMID:25337585

  19. Polymeric systems incorporating plant viral nanoparticles for tailored release of therapeutics.

    PubMed

    Honarbakhsh, Sara; Guenther, Richard H; Willoughby, Julie A; Lommel, Steven A; Pourdeyhimi, Behnam

    2013-07-01

    Therapeutic polylactide (PLA) nanofibrous matrices are fabricated by incorporating plant viral nanoparticles (PVNs) infused with fluorescent agents ethidium bromide (EtBr) and rhodamine (Rho), and cancer therapeutic doxorubicin (Dox). The native virus, Red clover necrotic mosaic virus (RCNMV), reversibly opens and closes upon exposure to the appropriate environmental stimuli. Infusing RCNMV with small molecules allows the incorporation of PVN(Active) into fibrous matrices via two methods: direct processing by in situ electrospinning of a polymer and PVNs solution or immersion of the matrix into a viral nanoparticle solution. Five organic solvents commonly in-use for electrospinning are evaluated for potential negative impact on RCNMV stability. In addition, leakage of rhodamine from the corresponding PVN(Rho) upon solvent exposure is determined. Incorporation of the PVN into the matrices are evaluated via transmission electron, scanning electron and fluorescent microscopies. Finally, the percent cumulative release of doxorubicin from both PLA nanofibers and PLA and polyethylene oxide (PEO) hybrid nanofibers demonstrate tailored release due to the incorporation of PVN(Dox) as compared to the control nanofibers with free Dox. Preliminary kinetic analysis results suggest a two-phase release profile with the first phase following a hindered Fickian transport mechanism for the release of Dox for the polymer-embedded PVNs. In contrast, the nanofiber matrices that incorporate PVNs through the immersion processing method followed a pseudo-first order kinetic transport mechanism. PMID:23335438

  20. Plasmon resonance at extreme temperatures in sputtered Au nanoparticle incorporated TiO2 films

    NASA Astrophysics Data System (ADS)

    Ohodnicki, Paul R.; Brown, Thomas D.; Buric, Michael P.; Baltrus, John P.; Chorpening, B.

    2012-09-01

    Sensor technologies that can operate under extreme conditions including high temperatures, high pressures, highly reducing and oxidizing environments, and corrosive gases are needed for process monitoring and control in advanced fossil energy applications. Au nanoparticle incorporated metal oxide thin films have recently been demonstrated to show a useful optical response to changing ambient gases at high temperatures as a result of modifications to the localized surface plasmon resonance (LSPR) of the Au nanoparticles. Au nanoparticle incorporated TiO2 films were prepared through sputter deposition techniques followed by high temperature oxidation treatments. Upon exposure to a 4% H2/N2 gas atmosphere at elevated temperatures, a shift of the absorption resonance associated with Au nanoparticles to shorter wavelengths is observed, as demonstrated in the literature previously. In this work, we also demonstrate that there is a shift of similar magnitude in the scattering resonance associated with Au. The LSPR absorption peak was monitored as a function of temperature up to 850oC demonstrating a broadening and a decrease in the maximum peak absorptance. Calculations performed in the quasistatic approximation are also presented to explain observed changes in LSPR as a function of temperature and to illustrate the effects on sensitivity of Au - based LSPR sensor materials for extreme temperature applications.

  1. Sorption, Solubility, Bond Strength and Hardness of Denture Soft Lining Incorporated with Silver Nanoparticles

    PubMed Central

    Chladek, Grzegorz; Kasperski, Jacek; Barszczewska-Rybarek, Izabela; ?mudzki, Jaros?aw

    2013-01-01

    The colonization of denture soft lining material by oral fungi can result in infections and stomatitis of oral tissues. In this study, 0 ppm to 200 ppm of silver nanoparticles was incorporated as an antimicrobial agent into composites to reduce the microbial colonization of lining materials. The effect of silver nanoparticle incorporation into a soft lining material on the sorption, solubility, hardness (on the Shore A scale) and tensile bond strength of the composites was investigated. The data were statistically analyzed using two-way ANOVA and Newman-Keuls post hoc tests or the chi-square Pearson test at the p < 0.05 level. An increase in the nanosilver concentration resulted in a decrease in hardness, an increase in sorption and solubility, a decrease in bond strength and a change in the failure type of the samples. The best combination of bond strength, sorption, solubility and hardness with antifungal efficacy was achieved for silver nanoparticle concentrations ranging from 20 ppm to 40 ppm. These composites did not show properties worse than those of the material without silver nanoparticles and exhibited enhanced in vitro antifungal efficiency. PMID:23271371

  2. Thermal stability of composite phase change material microcapsules incorporated with silver nano-particles

    Microsoft Academic Search

    Qingwen Song; Yi Li; Jianwei Xing; J. Y. Hu; Yuen Marcus

    2007-01-01

    This paper reports a study on the thermal stability of phase change material microcapsules that are incorporated with silver nano-particles (Ag-NPs). The novel microcapsules were fabricated by the technique of in situ polymerization, with aminoplast as the wall and phase change material bromo-hexadecane (PCM BrC16) as the core. Thermal gravimetry (TG) analysis was applied to measure the thermal stability of

  3. Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation

    SciTech Connect

    Kim, C.S.; Lentini, C.J.; Waychunas, G.A.

    2008-09-15

    The interaction of metal ions and oxyanions with nanoscale mineral phases has not yet been extensively studied despite the increased recognition of their prevalence in natural systems as a significant component of geomedia. A combination of macroscopic uptake studies to investigate the adsorption behavior of As(V), Cu(II), Hg(II), and Zn(II) onto nanoparticulate goethite ({alpha}-FeOOH) as a function of aging time at elevated temperature (75 C) and synchrotron-based X-ray studies to track changes in both the sorption mode and the rate of nanoparticle growth reveal the effects that uptake has on particle growth. Metal(loid) species which sorb quickly to the iron oxyhydroxide particles (As(V), Cu(II)) appear to passivate the particle surface, impeding the growth of the nanoparticles with progressive aging; in contrast, species that sorb more slowly (Hg(II), Zn(II)) have considerably less impact on particle growth. Progressive changes in the speciation of these particular metals with time suggest shifts in the mode of metal uptake with time, possibly indicating structural incorporation of the metal(loid) into the nanoparticle; this is supported by the continued increase in uptake concomitant with particle growth, implying that metal species may transform from surface-sorbed species to more structurally incorporated forms. This type of incorporation would have implications for the long-term fate and mobility of metals in contaminated regions, and affect the strategy for potential remediation/modeling efforts.

  4. Impact of magnetite nanoparticle incorporation on the eigenfrequencies of nanocomposite microcapsules

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Grishina, O. A.

    2015-03-01

    Modern researches showed that nanocomposite films with magnetite nanoparticle incorporation have good perspectives for applications in electronics to create antireflective coatings and also for biomedical applications to create coatings with remote control of physical properties using alternative magnetic field or microwave radiation, which is very important for fabrication of new generation substrates in tissue engineering and advanced drug delivery systems. In particular, the unique properties of advanced nanocomposite microcapsules allowed developing of the supramolecular system of targeted drug delivery. A study of the behavior of the nanocomposite shell of microcapsules, which consists of alternate layers of negatively charged iron oxide nanoparticles and cationic polyallylamine hydrochloride molecules, was carried out. The aim of the present study was to investigate the effect of the number of nanoparticle layers on magnetic properties of polyelectrolyte/nanoparticles nanocomposite microcapsules prepared via layer-by-layer technique using iron oxide colloids. In result of numerical simulation using ANSYS Workbench software the behavior of the nanocomposite shell of microcapsules depending on the concentration of magnetite particles in it was investigated. Modal and harmonic analysis of behavior of the microcapsules shell was conducted in water at a temperature of 37°. As a result of numerical experiment the eigenfrequencies and mode shape were first time defined for any modifications of the nanocomposite microcapsules. It has been established that the magnetic permeability value depends on the number of iron oxide nanoparticle layers in a nanocomposite microcapsule.

  5. Three-Phase Co-assembly: In Situ Incorporation of Nanoparticles into Tunable, Highly Ordered, Porous Silica Films

    E-print Network

    Aizenberg, Joanna

    particles furthermore enhances the hue and saturation of the inverse opals' color by suppressing incoherent. The incorporation of metal nanoparticles into inverse opals has recently attracted particular attention22,23 or catalytic24 properties of metal nanoparticles greatly expand the possible applications

  6. Effect of silver nanoparticles incorporation on viscoelastic properties of acrylic resin denture base material

    PubMed Central

    Mahross, Hamada Zaki; Baroudi, Kusai

    2015-01-01

    Objective: The objective was to investigate the effect of silver nanoparticles (AgNPs) incorporation on viscoelastic properties of acrylic resin denture base material. Materials and Methods: A total of 20 specimens (60 × 10 × 2 mm) of heat cured acrylic resin were constructed and divided into four groups (five for each), according to the concentration of AgNPs (1%, 2%, and 5% vol.) which incorporated into the liquid of acrylic resin material and one group without additives (control group). The dynamic viscoelastic test for the test specimens was performed using the computerized material testing system. The resulting deflection curves were analyzed by material testing software NEXYGEN MT. Results: The 5% nanoparticles of silver (NAg) had significantly highest mean storage modulus E’ and loss tangent Tan ? values followed by 2% NAg (P < 0.05). For 1% nanosilver incorporation (group B), there were no statistically significant differences in storage modulus E’, lost modulus E” or loss tangent Tan ? with other groups (P > 0.05). Conclusion: The AgNPs incorporation within the acrylic denture base material can improve its viscoelastic properties.

  7. Claudin 4-targeted protein incorporated into PLGA nanoparticles can mediate M cell targeted delivery

    PubMed Central

    Rajapaksa, Thejani E.; Stover-Hamer, Mary; Fernandez, Xiomara; Eckelhoefer, Holly A.; Lo, David D.

    2009-01-01

    Polymer-based microparticles are in clinical use mainly for their ability to provide controlled release of peptides and compounds, but they are also being explored for their potential to deliver vaccines and drugs as suspensions directly into mucosal sites. It is generally assumed that uptake is mediated by epithelial M cells, but this is often not directly measured. To study the potential for optimizing M cell uptake of polymer microparticles in vivo, we produced sub-micron size PLGA particles incorporating a recombinant protein. This recombinant protein was produced with or without a c-terminal peptide previously shown to have high affinity binding to Claudin 4, a protein associated with M cell endocytosis. While the PLGA nanoparticles incorporate the protein throughout the matrix, much of the protein was also displayed on the surface, allowing us to take advantage of the binding activity of the targeting peptide. Accordingly, we found that instillation of these nanoparticles into the nasal passages or stomach of mice was found to significantly enhance their uptake by upper airway and intestinal M cells. Our results suggest that a reasonably simple nanoparticle manufacture method can provide insight into developing an effective needle-free delivery system. PMID:19896996

  8. The incorporation of nanoparticles into conventional glass-ionomer dental restorative cements.

    PubMed

    Gjorgievska, Elizabeta; Van Tendeloo, Gustaaf; Nicholson, John W; Coleman, Nichola J; Slipper, Ian J; Booth, Samantha

    2015-04-01

    Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil® Rock and EQUIA™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil® Rock also showed no significant difference with zirconia. By contrast, ChemFil® Rock showed significantly higher compressive strength with added titania, and EQUIA™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs. PMID:25691120

  9. Biodistribution and in vivo activities of tumor-associated macrophage-targeting nanoparticles incorporated with doxorubicin.

    PubMed

    Niu, Mengmeng; Naguib, Youssef W; Aldayel, Abdulaziz M; Shi, Yan-chun; Hursting, Stephen D; Hersh, Matthew A; Cui, Zhengrong

    2014-12-01

    Tumor-associated macrophages (TAMs) are increasingly considered a viable target for tumor imaging and therapy. Previously, we reported that innovative surface-functionalization of nanoparticles may help target them to TAMs. In this report, using poly(lactic-co-glycolic) acid (PLGA) nanoparticles incorporated with doxorubicin (DOX) (DOX-NPs), we studied the effect of surface-modification of the nanoparticles with mannose and/or acid-sensitive sheddable polyethylene glycol (PEG) on the biodistribution of DOX and the uptake of DOX by TAMs in tumor-bearing mice. We demonstrated that surface-modification of the DOX-NPs with both mannose and acid-sensitive sheddable PEG significantly increased the accumulation of DOX in tumors, enhanced the uptake of the DOX by TAMs, but decreased the distribution of DOX in mononuclear phagocyte system (MPS), such as liver. We also confirmed that the acid-sensitive sheddable PEGylated, mannose-modified DOX-nanoparticles (DOX-AS-M-NPs) targeted TAMs because depletion of TAMs in tumor-bearing mice significantly decreased the accumulation of DOX in tumor tissues. Furthermore, in a B16-F10 tumor-bearing mouse model, we showed that the DOX-AS-M-NPs were significantly more effective than free DOX in controlling tumor growth but had only minimum effect on the macrophage population in mouse liver and spleen. The AS-M-NPs are promising in targeting cytotoxic or macrophage-modulating agents into tumors to improve tumor therapy. PMID:25314115

  10. Paclitaxel-incorporated nanoparticles using block copolymers composed of poly(ethylene glycol)/poly(3-hydroxyoctanoate)

    PubMed Central

    2014-01-01

    Block copolymers composed of poly(3-hydroxyoctanoate) (PHO) and methoxy poly(ethylene glycol) (PEG) were synthesized to prepare paclitaxel-incorporated nanoparticle for antitumor drug delivery. In a 1H-NMR study, chemical structures of PHO/PEG block copolymers were confirmed and their molecular weight (M.W.) was analyzed with gel permeation chromatography (GPC). Paclitaxel as a model anticancer drug was incorporated into the nanoparticles of PHO/PEG block copolymer. They have spherical shapes and their particle sizes were less than 100 nm. In a 1H-NMR study in D2O, specific peaks of PEG solely appeared while peaks of PHO disappeared, indicating that nanoparticles have core-shell structures. The higher M.W. of PEG decreased loading efficiency and particle size. The higher drug feeding increased drug contents and average size of nanoparticles. In the drug release study, the higher M.W. of PEG block induced the acceleration of drug release rate. The increase in drug contents induced the slow release rate of drug. In an antitumor activity study in vitro, paclitaxel nanoparticles have practically similar anti-proliferation activity against HCT116 human colon carcinoma cells. In an in vivo animal study using HCT116 colon carcinoma cell-bearing mice, paclitaxel nanoparticles have enhanced antitumor activity compared to paclitaxel itself. Therefore, paclitaxel-incorporated nanoparticles of PHO/PEG block copolymer are a promising vehicle for antitumor drug delivery. PMID:25288916

  11. Preparation and Characterization of Selenium Incorporated Guar Gum Nanoparticle and Its Interaction with H9c2 Cells

    PubMed Central

    Soumya, Rema Sreenivasan; Vineetha, Vadavanath Prabhakaran; Reshma, Premachandran Latha; Raghu, Kozhiparambil Gopalan

    2013-01-01

    This study deals with the preparation and characterization of selenium incorporated guar gum nanoparticle (SGG), and its effect on H9c2 cardiomyoblast. Herein, nanoprecipitation techniques had been employed for the preparation of SGG nanoparticle. The prepared nanoparticle had been subjected to various types of analytical techniques like transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size analysis to confirm the characteristics of nanoparticle as well as for selenium incorporation. Physical characterization of nanoparticle showed that the size of nanoparticles increase upto ?69–173 nm upon selenium incorporation from ?41–132 nm. Then the prepared nanoparticles were evaluated for its effect on H9c2 cells. In this regard, the effect of nanoparticle on various vital parameters of H9c2 cells was studied. Parameters like cell viability, uptake of selenium incorporated guar gum nanoparticle by the cells, effect of SGG on DNA integrity, apoptosis, reactive oxygen species generation, alteration in transmembrane potential of mitochondria and cytoskeletal integrity had been investigated. Viability results showed that up to 25 nM of SGG was safe (10.31%) but beyond that it induces cytotoxicity. Cellular uptake of selenium showed that cell permeability for SGG is significantly high compared to normal selenium (7.2 nM of selenium for 25 nM SGG compared with 5.2 nM selenium for 25 nM sodium selenite). There was no apoptosis with SGG and also it protects DNA from hydroxyl radical induced breakage. Likewise no adverse effect on mitochondria and cytoskeleton was observed for 25 nM of SGG. Overall results reveal that SGG is highly suitable for biomedical research application. PMID:24098647

  12. Nanocomposites Fabricated by a Combination of Green Compact Nanoparticle Incorporation and Ultrasonic Treatment of the Melted Compact

    NASA Astrophysics Data System (ADS)

    Kandemir, Sinan; Atkinson, Helen V.; Weston, David P.; Hainsworth, Sarah V.

    2014-11-01

    Thixoforming is a type of semi-solid processing which is based on forming metals in the semi-solid state rather than fully liquid or solid state. There have been no reports of the thixoforming of nanocomposites in the literature. The incorporation of ceramic nanoparticles into liquid metals is a challenging task for the fabrication of metal matrix nanocomposites due to their large surface-to-volume ratio and poor wettability. Previous research work by a number of workers has highlighted the challenges with the incorporation of nanoparticles into liquid aluminum alloy. In the present study, SiC and TiB2 nanoparticles with an average diameter between 20 and 30 nm were firstly incorporated into green compacts by a powder forming route, and then the compacts were melted and treated ultrasonically. The microstructural studies reveal that the engulfment and relatively effective distribution of the nanoparticles into the melt were achieved. The hardness was considerably improved with only 0.8 wt pct addition of the nanoparticles. The nanocomposites were successfully thixoformed at a solid fraction between 0.65 and 0.70. The microstructures, hardness, and tensile mechanical properties of the thixoformed nanocomposites were investigated and compared with those of the as-received A356 and thixoformed A356 alloys. The tensile properties of the thixoformed nanocomposites were significantly enhanced compared to thixoformed A356 alloy without reinforcement, indicating the strengthening effects of the nanoparticles.

  13. Rapid synthesis of ordered hexagonal mesoporous silica and their incorporation with Ag nanoparticles by solution plasma

    SciTech Connect

    Pootawang, Panuphong, E-mail: p.pootawang@gmail.com [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)] [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of); Saito, Nagahiro; Takai, Osamu [EcoTopia Science and Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)] [EcoTopia Science and Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Lee, Sang Yul [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)] [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)

    2012-10-15

    Graphical abstract: Overall reactions of mesoporous silica and AgNPs-incorporated mesoporous silica syntheses by solution plasma process (SPP). Highlights: ? SPP for rapid synthesis of mesoporous silica. ? SPP for rapid synthesis of mesoporous silica and AgNPs incorporation. ? Higher surface area and larger pore diameter of mesoporous silica synthesized by SPP. -- Abstract: Rapid synthesis of silica with ordered hexagonal mesopore arrangement was obtained using solution plasma process (SPP) by discharging the mixture of P123 triblock copolymer/TEOS in acid solution. SPP, moreover, was utilized for Ag nanoparticles (AgNPs) incorporation in silica framework as one-batch process using silver nitrate (AgNO{sub 3}) solution as precursor. The turbid silicate gel was clearly observed after discharge for 1 min and the white precipitate formed at 3 min. The mesopore with hexagonal arrangement and AgNPs were observed in mesoporous silica. Two regions of X-ray diffraction patterns (2? < 2° and 2? = 35–90°) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional sol–gel route, surface area and pore diameter of mesoporous silica prepared by solution plasma were observed to be larger. In addition, the increase in Ag loading resulted in the decrease in surface area with insignificant variation in the pore diameter of mesoporous silica. SPP could be successfully utilized not only to enhance gelation time but also to increase surface area and pore diameter of mesoporous silica.

  14. Impact of magnetite nanoparticle incorporation on optical and electrical properties of nanocomposite LbL assemblies.

    PubMed

    Yashchenok, Alexey M; Gorin, Dmitry A; Badylevich, Mikhail; Serdobintsev, Alexey A; Bedard, Matthieu; Fedorenko, Yanina G; Khomutov, Gennady B; Grigoriev, Dmitri O; Möhwald, Helmuth

    2010-09-21

    Optical and electrical properties of polyelectrolyte/iron oxide nanocomposite planar films on silicon substrates were investigated for different amount of iron oxide nanoparticles incorporated in the films. The nanocomposite assemblies prepared by the layer-by-layer assembly technique were characterized by ellipsometry, atomic force microscopy, and secondary ion mass-spectrometry. Absorption spectra of the films reveal a shift of the optical absorption edge to higher energy when the number of deposited layers decreases. Capacitance-voltage and current-voltage measurements were applied to study the electrical properties of metal-oxide-semiconductor structures prepared by thermal evaporation of gold electrodes on nanocomposite films. The capacitance-voltage measurements show that the dielectric constant of the film increases with the number of deposited layers and the fixed charge and the trapped charge densities have a negative sign. PMID:20602000

  15. Enhanced recovery and dissolution of griseofulvin nanoparticles from surfactant-free nanocomposite microparticles incorporating wet-milled swellable dispersants.

    PubMed

    Bhakay, Anagha; Azad, Mohammad; Vizzotti, Emanuel; Dave, Rajesh N; Bilgili, Ecevit

    2014-11-01

    Nanocomposite microparticles (NCMPs) incorporating drug nanoparticles and wet-milled swellable dispersant particles were investigated as a surfactant-free drug delivery vehicle with the goal of enhancing the nanoparticle recovery and dissolution rate of poorly water-soluble drugs. Superdisintegrants were used as inexpensive, model, swellable dispersant particles by incorporating them into NCMP structure with or without wet-stirred media milling along with the drug. Suspensions of griseofulvin (GF, model drug) along with various dispersants produced by wet-milling were coated onto Pharmatose® to prepare NCMPs in a fluidized bed process. Hydroxypropyl cellulose (HPC, polymer) alone and with sodium dodecyl sulfate (SDS, surfactant) was used as base-line stabilizer/dispersant during milling. Croscarmellose sodium (CCS, superdisintegrant) and Mannitol were used as additional dispersants to prepare surfactant-free NCMPs. Nanoparticle recovery during redispersion and dissolution of the various GF-laden NCMPs were examined. Suspensions prepared by co-milling GF/HPC/CCS or milling GF/HPC/SDS were stable after 30 h of storage. After drying, due to its extensive swelling capacity, incorporation of wet-milled CCS in the NCMPs caused effective breakage of the NCMP structure and bursting of nanoparticle clusters, ultimately leading to fast recovery of the GF nanoparticles. Optimized wet co-milling and incorporation of CCS in NCMP structure led to superior dispersant performance over incorporation of unmilled CCS or physically mixed unmilled CCS with NCMPs. The enhanced redispersion correlated well with the fast GF dissolution from the NCMPs containing either CCS particles or SDS. Overall, swellable dispersant (CCS) particles, preferably in multimodal size distribution, enable a surfactant-free formulation for fast recovery/dissolution of the GF nanoparticles. PMID:23981202

  16. Behavior and anti-glioma effect of lapatinib-incorporated lipoprotein-like nanoparticles

    NASA Astrophysics Data System (ADS)

    Gao, Huile; Yang, Zhi; Cao, Shijie; Xi, Zhangjie; Zhang, Shuang; Pang, Zhiqing; Jiang, Xinguo

    2012-11-01

    The purpose of the investigation was to prepare a new type of nanoparticle, namely lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs), and to evaluate the behavior and anti-glioma effect of LTNPs. LTNPs were prepared and characterized using the Cyro-transmission electron microscope (Cryo-TEM) and Raman scan methods. Cellular uptake and subcellular localization studies were performed to evaluate the in vitro behavior of LTNPs. An in vivo imaging technique was used for the evaluation of the targeting of LTNPs. To study the anti-glioma effect, glioma xenografts were used. The particle size of LTNPs was 92.6 nm, and the zeta potential was 28.40 mV. LTNPs contained a surface layer that was obviously different from the core, according to the Cryo-TEM analysis. A Raman scan analysis demonstrated the incorporation of lapatinib in LTNPs, and it also revealed a structure different from free lapatinib. The uptake of LTNP by U87 cells occurred in a concentration- and time-dependent manner. According to the subcellular study, the uptake of LTNPs was endosome mediated. LTNPs could distribute and accumulate in the tumor site by an enhanced permeation and retention effect. Both LTNPs (10 mg kg-1) and LTNPs (30 mg kg-1) could significantly inhibit the growth of U87 xenografts. For a similar antitumor effect, the required cumulative dose of LTNPs was only 5% compared to that of Tykerb (the commercial formulation of lapatinib). This study demonstrated the effective uptake of LTNPs by U87 cells, the passive targeting of LTNPs at tumors and the better antitumor effect of LTNPs.

  17. Encapsulation of Mono- or Bimetal Nanoparticles Inside Metal-Organic Frameworks via In situ Incorporation of Metal Precursors.

    PubMed

    Chen, Liyu; Chen, Xiaodong; Liu, Hongli; Li, Yingwei

    2015-06-01

    A facile, in situ metal precursor incorporation strategy is established for good control over the location and composition of metal nanoparticles within metal-organic frameworks (MOFs). This one-step metal precursor incorporation route is successfully applied to the fabrication of ultrafine Pd, Ni, and PdNi alloys to be selectively encapsulated inside the pores of MOFs, achieving superior catalytic activity and stability in the hydrogenation of nitrobenzene. PMID:25644718

  18. Core-shell nano-architectures: the incorporation mechanism of hydrophobic nanoparticles into the aqueous core of a microemulsion.

    PubMed

    Scorciapino, Mariano A; Sanna, Roberta; Ardu, Andrea; Orrù, Federica; Casu, Mariano; Musinu, Anna; Cannas, Carla

    2013-10-01

    This work presents an in-depth investigation of the molecular interactions in the incorporation mechanism of colloidal hydrophobic-capped nanoparticles into the hydrophilic core of reverse microemulsions. (1)H Nuclear Magnetic Resonance (NMR) was employed to obtain molecular level details of the interaction between the nanoparticles capping amphiphiles and the microemulsion surfactants. The model system of choice involved oleic acid (OAC) and oleylamine (OAM) as capping molecules, while igepal-CO520 was the surfactant. The former were studied both in their "free" state and "ligated" one, i.e., bound to nanoparticles. The latter was investigated either in cyclohexane (micellar solution) or in water/cyclohexane microemulsions. The approach was extremely useful to gain a deeper understanding of the equilibria involved in this complex system (oleic acid capped-Bi2S3 in igepal/water/cyclohexane microemulsions). In difference to previously proposed mechanisms, the experimental data showed that the high affinity of the capping ligands for the reverse micelle interior was the drivingforce for the incorporation of the nanoparticles. A simple ligand-exchange mechanism could be ruled out. The collected information about the nanoparticle incorporation mechanism is extremely useful to develop new synthetic routes with an improved/tuned coating efficiency, in order to tailor the core-shell structure preparation. PMID:23910706

  19. The chemopreventive effect of the dietary compound kaempferol on the MCF-7 human breast cancer cell line is dependent on inhibition of glucose cellular uptake.

    PubMed

    Azevedo, Cláudia; Correia-Branco, Ana; Araújo, João R; Guimarães, João T; Keating, Elisa; Martel, Fátima

    2015-01-01

    Our aim was to investigate the effect of several dietary polyphenols on glucose uptake by breast cancer cells. Uptake of (3)H-deoxy-D-glucose ((3)H-DG) by MCF-7 cells was time-dependent, saturable, and inhibited by cytochalasin B plus phloridzin. In the short-term (26 min), myricetin, chrysin, genistein, resveratrol, kaempferol, and xanthohumol (10-100 µM) inhibited (3)H-DG uptake. Kaempferol was found to be the most potent inhibitor of (3)H-DG uptake [IC50 of 4 µM (1.6-9.8)], behaving as a mixed-type inhibitor. In the long-term (24 h), kaempferol (30 µM) was also able to inhibit (3)H-DG uptake, associated with a 40% decrease in GLUT1 mRNA levels. Interestingly enough, kaempferol (100 µM) revealed antiproliferative (sulforhodamine B and (3)H-thymidine incorporation assays) and cytotoxic (extracellular lactate dehydrogenase activity determination) properties, which were mimicked by low extracellular (1 mM) glucose conditions and reversed by high extracellular (20 mM) glucose conditions. Finally, exposure of cells to kaempferol (30 µM) induced an increase in extracellular lactate levels over time (to 731 ± 32% of control after a 24 h exposure), due to inhibition of MCT1-mediated lactate cellular uptake. In conclusion, kaempferol potently inhibits glucose uptake by MCF-7 cells, apparently by decreasing GLUT1-mediated glucose uptake. The antiproliferative and cytotoxic effect of kaempferol in these cells appears to be dependent on this effect. PMID:25719685

  20. Effects of starch on nitrous acid-induced oxidation of kaempferol and inhibition of ?-amylase-catalysed digestion of starch by kaempferol under conditions simulating the stomach and the intestine.

    PubMed

    Takahama, Umeo; Hirota, Sachiko

    2013-11-01

    Kaempferol glycosides can be hydrolyzed to their aglycone kaempferol during cooking under acidic conditions and in the oral cavity and the intestine by glycosidases. Kaempferol was oxidised by nitrite under acidic conditions (pH 2.0) to produce nitric oxide (NO), and the nitrite-induced oxidation of kaempferol was enhanced and inhibited by 10 and 100mg of starch ml(-1), respectively. The opposite effects of starch were discussed by considering the binding of kaempferol to starch and starch-dependent inhibition of the accessibility of nitrous acid to kaempferol. Kaempferol inhibited ?-amylase-catalysed starch digestion by forming starch/kaempferol complexes, and the inhibitory effects increased in the order of amylopectinkaempferol were discussed to be due to the difference in binding sites of kaempferol between amylose and amylopectin. From the present study, dual-function of kaempferol became apparent in the digestive tract. PMID:23768363

  1. Colorimetric cholesterol sensor based on peroxidase like activity of zinc oxide nanoparticles incorporated carbon nanotubes.

    PubMed

    Hayat, Akhtar; Haider, Waqar; Raza, Yousuf; Marty, Jean Louis

    2015-10-01

    A sensitive and selective colorimetric method based on the incorporation of zinc oxide nanoparticles (ZnO NPs) on the surface of carbon nanotubes (CNTs) was shown to posses synergistic peroxidase like activity for the detection of cholesterol. The proposed nanocomposite catalyzed the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in the presence of hydrogen peroxide (H2O2) to produce a green colored product which can be monitored at 405nm. H2O2 is the oxidative product of cholesterol in the presence of cholesterol oxidase. Therefore, the oxidation of cholesterol can be quantitatively related to the colorimetric response by combining these two reactions. Under the optimal experimental conditions, the colorimetric response was proportional to the concentration of cholesterol in the range of 0.5-500nmol/L, with a detection limit of 0.2nmol/L. The applicability of the proposed assays was demonstrated for the determination of cholesterol in milk powder samples with good recovery results. PMID:26078143

  2. Incorporation of functionalized gold nanoparticles into nanofibers for enhanced attachment and differentiation of mammalian cells

    PubMed Central

    2012-01-01

    Background Electrospun nanofibers have been widely used as substrata for mammalian cell culture owing to their structural similarity to natural extracellular matrices. Structurally consistent electrospun nanofibers can be produced with synthetic polymers but require chemical modification to graft cell-adhesive molecules to make the nanofibers functional. Development of a facile method of grafting functional molecules on the nanofibers will contribute to the production of diverse cell type-specific nanofiber substrata. Results Small molecules, peptides, and functionalized gold nanoparticles were successfully incorporated with polymethylglutarimide (PMGI) nanofibers through electrospinning. The PMGI nanofibers functionalized by the grafted AuNPs, which were labeled with cell-adhesive peptides, enhanced HeLa cell attachment and potentiated cardiomyocyte differentiation of human pluripotent stem cells. Conclusions PMGI nanofibers can be functionalized simply by co-electrospinning with the grafting materials. In addition, grafting functionalized AuNPs enable high-density localization of the cell-adhesive peptides on the nanofiber. The results of the present study suggest that more cell type-specific synthetic substrata can be fabricated with molecule-doped nanofibers, in which diverse functional molecules are grafted alone or in combination with other molecules at different concentrations. PMID:22686683

  3. On the incorporation of Rhodamine B and 2?,7?-dichlorofluorescein dyes in silica: Synthesis of fluorescent nanoparticles

    NASA Astrophysics Data System (ADS)

    Gomes, Elis C. C.; de Carvalho, Idalina M. M.; Diógenes, Izaura C. N.; de Sousa, Eduardo H. S.; Longhinotti, Elisane

    2014-05-01

    The present paper reports the incorporation of 2?,7?-dichlorofluorescein (DCF) and Rhodamine B (RhB) dyes in silica nanoparticles by using the Stöber's method with some modifications. Based on infrared and electronic spectroscopies, these dyes were successfully incorporated resulting in fluorescent nanomaterials of an average size of 80 nm. A composite fluorescent nanomaterial containing both dyes was also synthesized and showed the occurrence of Förster resonant energy transfer process (FRET) with the average distance between the donor (DCF) and acceptor (RhB) of 3.6 nm. Furthermore, these fluorescent nanoparticles were modified with folic acid producing nanomaterials whose Zeta potential values were in the range of -2 to -13 mV. These values are consistent with the low dispersivity observed by TEM micrographs. Altogether, these suitable properties can lead to the development of nanomaterials for cancer bioimaging and drug release.

  4. Characterization of natural organic matter treated by iron oxide nanoparticle incorporated ceramic membrane-ozonation process.

    PubMed

    Park, Hosik; Kim, Yohan; An, Byungryul; Choi, Heechul

    2012-11-15

    In this study, changes in the physical and structural properties of natural organic matter (NOM) were observed during hybrid ceramic membrane processes that combined ozonation with ultrafiltration ceramic membrane (CM) or with a reactive ceramic membrane (RM), namely, an iron oxide nanoparticles (IONs) incorporated-CM. NOM from feed water and NOM from permeate treated with hybrid ceramic membrane processes were analyzed by employing several NOM characterization techniques. Specific ultraviolet absorbance (SUVA), high-performance size exclusion chromatography (HPSEC) and fractionation analyses showed that the hybrid ceramic membrane process effectively removed and transformed relatively high contents of aromatic, high molecular weight and hydrophobic NOM fractions. Fourier transform infrared spectroscopy (FTIR) and 3-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy revealed that this process caused a significant decrease of the aromaticity of humic-like structures and an increase in electron withdrawing groups. The highest removal efficiency (46%) of hydroxyl radical probe compound (i.e., para-Chlorobenzoic acid (pCBA)) in RM-ozonation process compared with that in CM without ozonation process (8%) revealed the hydroxyl radical formation by the surface-catalyzed reaction between ozone and IONs on the surface of RM. In addition, experimental results on flux decline showed that fouling of RM-ozonation process (15%) was reduced compared with that of CM without ozonation process (30%). These results indicated that the RM-ozonation process enhanced the destruction of NOM and reduced the fouling by generating hydroxyl radicals from the catalytic ozonation in the RM-ozonation process. PMID:22944203

  5. Lapatinib-incorporated lipoprotein-like nanoparticles: preparation and a proposed breast cancer-targeting mechanism

    PubMed Central

    Zhang, Li; Zhang, Shuang; Ruan, Shao-bo; Zhang, Qian-yu; He, Qin; Gao, Hui-le

    2014-01-01

    Aim: Lapatinib is a dual inhibitor of EGFR and human epidermal growth factor receptor 2 (HER2), and used to treat advanced breast cancer. To overcome its poor water solubility, we constructed lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs), and evaluated the particle characteristics and possible anti-breast cancer mechanisms. Methods: LTNPs (lapatinib bound to albumin as a core, and egg yolk lecithin forming a lipid corona) were prepared. The particle characteristics were investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The uptake and subcellular localization of LTNPs, as well as the effects of LTNPs on cell cycle were examined in BT-474 human breast cancer cells in vitro. Mice bearing BT-474 subcutaneous xenograft were intravenously injected with coumarin-6 loaded LTNPs (30 mg/kg) to study the targeting mechanisms in vivo. Results: The LTNPs particles were generally spherical but flexible under TEM and AFM, and approximately 62.1 nm in size with a zeta potential of 22.80 mV. In BT-474 cells, uptake of LTNPs was mediated by endosomes through energy-dependent endocytosis involving clathrin-dependent pinocytosis and macropinocytosis, and they could effectively escape from endosomes to the cytoplasm. Treatment of BT-474 cells with LTNPs (20 ?g/mL) induced a significant cell arrest at G0/G1 phase compared with the same concentration of lapatinib suspension. In mice bearing BT-474 xenograft, intravenously injected LTNPs was found to target and accumulate in tumors, and colocalized with HER2 and SPRAC (secreted protein, acidic and rich in cysteine). Conclusion: LTNPs can be taken up into breast cancer cells through specific pathways in vitro, and targeted to breast cancer xenograft in vivo via enhanced permeability and retention effect and SPARC. PMID:24902791

  6. Microfiber coupler based biosensor incorporating a layer of gold nanoparticles with improved sensitivity

    NASA Astrophysics Data System (ADS)

    Semenova, Yuliya; Bo, Lin; Wang, Pengfei; Tian, Furong; Byrne, Hugh; Farrell, Gerald

    2014-05-01

    We studied the effect of a star-shaped gold nanoparticles layer coated on the surface of the microfiber coupler (MFC) on the sensitivity of the embedded MFC biosensor. It is shown that deposition of the layer of star-shaped gold nanoparticles on the MFC sensor surface results in a significantly increased spectral shift (on average 3.05 nm shift compared to a 1.08 nm shift per layer of electrolyte for the sample without the nanoparticles layer). In addition, introducing the nanoparticle layer results in the decrease of the transmission power; measurement of the changes in transmission also could be used as a means for the sensor interrogation.

  7. CCMR: Incorporating Surface Plasmons into Hybrid Core-Shell Fluorescent Silica Nanoparticles

    NSDL National Science Digital Library

    Belgrave, Akeisha

    2007-08-29

    Fluorescent silica nanoparticles are widely used in bioimaging, bioassay, and nanomedicine applications.[1] In such applications the control of fluorescence intensity is desirable. It is known that introducing a metallic particle or shell to such fluorescent silica nanoparticles can create a surface plasmon interaction between the metal and the fluorescent dye, potentially allowing for enhancement of the fluorescence intensity. This paper describes the synthesis of two types of hybrid nanoparticles with a fluorescent dye core-shell silica structure coated with small gold nanoparticles and a gold core surrounded by a silica shell of pure silica with Oregon green-488 dye in a second silica shell attached to the surface. The structure of these nanoparticles was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS), while their optical properties were investigated by spectrophotometry and fluorometry.

  8. Kaempferol ameliorates symptoms of metabolic syndrome by regulating activities of liver X receptor-?.

    PubMed

    Hoang, Minh-Hien; Jia, Yaoyao; Mok, Boram; Jun, Hee-Jin; Hwang, Kwang-Yeon; Lee, Sung-Joon

    2015-08-01

    Kaempferol is a dietary flavonol previously shown to regulate cellular lipid and glucose metabolism. However, its molecular mechanisms of action and target proteins have remained elusive, probably due to the involvement of multiple proteins. This study investigated the molecular targets of kaempferol. Ligand binding of kaempferol to liver X receptors (LXRs) was quantified by time-resolved fluorescence resonance energy transfer and surface plasmon resonance analyses. Kaempferol directly binds to and induces the transactivation of LXRs, with stronger specificity for the ?-subtype (EC50=0.33?M). The oral administration of kaempferol in apolipoprotein-E-deficient mice (150mg/day/kg body weight) significantly reduced plasma glucose and increased high-density lipoprotein cholesterol levels and insulin sensitivity compared with the vehicle-fed control. Kaempferol also reduced plasma triglyceride concentrations and did not cause liver steatosis, a common side effect of potent LXR activation. In immunoblotting analysis, kaempferol reduced the nuclear accumulation of sterol regulatory element-binding protein-1 (SREBP-1). Our results show that the suppression of SREBP-1 activity and the selectivity for LXR-? over LXR-? by kaempferol contribute to the reductions of plasma and hepatic triglyceride concentrations in mice fed kaempferol. They also suggest that kaempferol activates LXR-? and suppresses SREBP-1 to enhance symptoms in metabolic syndrome. PMID:25959373

  9. Gd{sup 3+} incorporated ZnO nanoparticles: A versatile material

    SciTech Connect

    Kumar, Surender, E-mail: surender40@gmail.com; Sahare, P.D.

    2014-03-01

    Graphical abstract: - Highlights: • Chemically synthesized Gd{sup 3+} doped ZnO nanoparticles. • The broad visible emission of the ZnO is dependent on the surface defects and can be tailored by Gd{sup 3+} doing. • PL and magnetic properties are modified by Gd{sup 3+} doping. • Photocatalysis experiment reveals that the ZnO: Gd{sup 3+} degrades the Rh B dye faster than the undoped ZnO. - Abstract: Gd{sup 3+} doped ZnO nanoparticles are synthesized by wet chemical route method and investigated through structural, optical, magnetic and photocatalytic properties. Transmission Electron Microscopy technique has been performed on undoped and Gd{sup 3+} doped ZnO nanoparticles. X-ray diffraction, X-ray photoelectron spectroscopy and Raman analyses are carried out in order to examine the desired phase formation and substitution of Gd{sup 3+} in the ZnO matrix. Gd{sup 3+} doped ZnO nanoparticles show enhanced photoluminescent and ferromagnetic properties as compared to undoped ZnO. The broad visible emission of ZnO is found to be largely dependent on the surface defects and these surface defects can be tailored by Gd{sup 3+} doping concentration. Furthermore, Gd{sup 3+} doped ZnO nanoparticles also show improved photocatalytic properties as compared with undoped ZnO nanoparticles under ultraviolet irradiation.

  10. Novel insights into the inhibitory mechanism of kaempferol on xanthine oxidase.

    PubMed

    Wang, Yajie; Zhang, Guowen; Pan, Junhui; Gong, Deming

    2015-01-21

    Xanthine oxidase (XO), a key enzyme in purine catabolism, is widely distributed in human tissues. It can catalyze xanthine to generate uric acid and cause hyperuricemia and gout. Inhibition kinetics assay showed that kaempferol inhibited XO activity reversibly in a competitive manner. Strong fluorescence quenching and conformational changes of XO were found due to the formation of a kaempferol-XO complex, which was driven mainly by hydrophobic forces. The molecular docking further revealed that kaempferol inserted into the hydrophobic cavity of XO to interact with some amino acid residues. The main inhibition mechanism of kaempferol on XO activity may be due to the insertion of kaempferol into the active site of XO occupying the catalytic center of the enzyme to avoid the entrance of the substrate and inducing conformational changes of XO. In addition, luteolin exhibited a stronger synergistic effect with kaempferol than did morin at the lower concentration. PMID:25539132

  11. A review of the dietary flavonoid, kaempferol on human health and cancer chemoprevention

    PubMed Central

    Chen, Allen Y.; Chen, Yi Charlie

    2013-01-01

    Kaempferol is a polyphenol antioxidant found in fruits and vegetables. Many studies have described the beneficial effects of dietary kaempferol in reducing the risk of chronic diseases, especially cancer. Epidemiological studies have shown an inverse relationship between kaempferol intake and cancer. Kaempferol may help by augmenting the body’s antioxidant defense against free radicals, which promote the development of cancer. At the molecular level, kaempferol has been reported to modulate a number of key elements in cellular signal transduction pathways linked to apoptosis, angiogenesis, inflammation, and metastasis. Significantly, kaempferol inhibits cancer cell growth and angiognesis and induces cancer cell apoptosis, but on the other hand, kaempferol appears to preserve normal cell viability, in some cases exerting a protective effect. The aim of this review is to synthesize information concerning the extraction of kaempferol, as well as to provide insights into the molecular basis of its potential chemo-preventative activities, with an emphasis on its ability to control intracellular signaling cascades that regulate the aforementioned processes. Chemoprevention using nanotechnology to improve the bioavailability of kaempferol is also discussed. PMID:23497863

  12. A review of the dietary flavonoid, kaempferol on human health and cancer chemoprevention.

    PubMed

    Chen, Allen Y; Chen, Yi Charlie

    2013-06-15

    Kaempferol is a polyphenol antioxidant found in fruits and vegetables. Many studies have described the beneficial effects of dietary kaempferol in reducing the risk of chronic diseases, especially cancer. Epidemiological studies have shown an inverse relationship between kaempferol intake and cancer. Kaempferol may help by augmenting the body's antioxidant defence against free radicals, which promote the development of cancer. At the molecular level, kaempferol has been reported to modulate a number of key elements in cellular signal transduction pathways linked to apoptosis, angiogenesis, inflammation, and metastasis. Significantly, kaempferol inhibits cancer cell growth and angiogenesis and induces cancer cell apoptosis, but on the other hand, kaempferol appears to preserve normal cell viability, in some cases exerting a protective effect. The aim of this review is to synthesize information concerning the extraction of kaempferol, as well as to provide insights into the molecular basis of its potential chemo-preventative activities, with an emphasis on its ability to control intracellular signaling cascades that regulate the aforementioned processes. Chemoprevention using nanotechnology to improve the bioavailability of kaempferol is also discussed. PMID:23497863

  13. Kaempferol induces chondrogenesis in ATDC5 cells through activation of ERK/BMP-2 signaling pathway.

    PubMed

    Nepal, Manoj; Li, Liang; Cho, Hyoung Kwon; Park, Jong Kun; Soh, Yunjo

    2013-12-01

    Endochondral bone formation occurs when mesenchymal cells condense to differentiate into chondrocytes, the primary cell types of cartilage. The aim of the present study was to identify novel factors regulating chondrogenesis. We investigated whether kaempferol induces chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Kaempferol treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. Kaempferol-treated ATDC5 cells stained more intensely with alcian blue staining than control cells, suggesting greater synthesis of matrix proteoglycans in the kaempferol-treated cells. Similarly, kaempferol induced greater activation of alkaline phosphatase activity than control cells, and it enhanced the expression of chondrogenic marker genes, such as collagen type I, collagen type X, OCN, Runx2, and Sox9. Kaempferol induced an acute activation of extracellular signal-regulated kinase (ERK) but not c-jun N-terminal kinase or p38 MAP kinase. PD98059, an inhibitor of MAPK/ERK, decreased in stained cells treated with kaempferol. Furthermore, kaempferol greatly expressed the protein and mRNA levels of BMP-2, suggesting chondrogenesis was stimulated via a BMP-2 pathway. Taken together, our results suggest that kaempferol has chondromodulating effects via an ERK/BMP-2 signaling pathway and could potentially be used as a therapeutic agent for bone growth disorders. PMID:23989061

  14. Microwave-assisted incorporation of silver nanoparticles in paper for point-of-use water purification.

    PubMed

    Dankovich, Theresa A

    2014-08-01

    This work reports an environmentally benign method for the in situ preparation of silver nanoparticles (AgNPs) in paper using microwave irradiation. Through thermal evaporation, microwave heating with an excess of glucose relative to the silver ion precursor yields nanoparticles on the surface of cellulose fibers within three minutes. Paper sheets were characterized by electron microscopy, UV-Visible reflectance spectroscopy, and atomic absorption spectroscopy. Antibacterial activity and silver release from the AgNP sheets were assessed for model Escherichia coli and Enterococci faecalis bacteria in deionized water and in suspensions that also contained with various influent solution chemistries, i.e. with natural organic matter, salts, and proteins. The paper sheets containing silver nanoparticles were effective in inactivating the test bacteria as they passed through the paper. PMID:25400935

  15. ???3-targeted Copper Nanoparticles Incorporating an Sn 2 Lipase-Labile Fumagillin Prodrug for Photoacoustic Neovascular Imaging and Treatment

    PubMed Central

    Zhang, Ruiying; Pan, Dipanjan; Cai, Xin; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Lanza, Gregory M.; Wang, Lihong V.

    2015-01-01

    Photoacoustic (PA) tomography enables multiscale, multicontrast and high-resolution imaging of biological structures. In particular, contrast-enhanced PA imaging offers high-sensitivity noninvasive imaging of neovessel sprout formation and nascent tubules, which are important biomarkers of malignant tumors and progressive atherosclerotic disease. While gold nanoparticles or nanorods have been used as PA contrast agents, we utilized high-density copper oleate small molecules encapsulated within a phospholipid surfactant (CuNPs) to generate a soft nanoparticle with PA contrast comparable to that from gold. Within the NIR window, the copper nanoparticles provided a 4-fold higher signal than that of blood. ???3-integrin targeting of CuNPs in a MatrigelTM angiogenesis mouse model demonstrated prominent (p<0.05) PA contrast enhancement of the neovasculature compared with mice given nontargeted or competitively inhibited CuNPs. Furthermore, incorporation of a Sn 2 lipase-labile fumagillin prodrug into the CuNP outer lipid membrane produced marked antiangiogenesis in the same model when targeted to the ???3-integrin, providing proof of concept in vivo for the first targeted PA - drug delivery agent. PMID:25553103

  16. Photoacoustic molecular imaging of angiogenesis using theranostic ???3-targeted copper nanoparticles incorporating a sn-2 lipase-labile fumagillin prodrug

    NASA Astrophysics Data System (ADS)

    Zhang, Ruiying; Cai, Xin; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Pan, Dipanjan; Lanza, Gregory M.; Wang, Lihong V.

    2014-03-01

    Photoacoustic (PA) tomography imaging is an emerging, versatile, and noninvasive imaging modality, which combines the advantages of both optical imaging and ultrasound imaging. It opens up opportunities for noninvasive imaging of angiogenesis, a feature of skin pathologies including cancers and psoriasis. In this study, high-density copper oleate encapsulated within a phospholipid surfactant (CuNPs) generated a soft nanoparticle with PA contrast comparable to gold. Within the near-infrared window, the copper nanoparticles can provide a signal more than 7 times higher that of blood. ???3-targeted of CuNPs in a Matrigel mouse model demonstrated prominent PA contrast enhancement of the neovasculature compared to mice given nontargeted or competitively inhibited CuNPs. Incorporation of a sn-2 lipase-labile fumagillin prodrug into the CuNPs produced marked antiangiogenesis in the same model, demonstrating the theranostic potential of a PA agent for the first time in vivo. With a PA signal comparable to gold-based nanoparticles yet a lower cost and demonstrated drug delivery potential, ???3-targeted CuNPs hold great promise for the management of skin pathologies with neovascular features.

  17. Controllable photoluminescence enhancement of CdTe/CdS quantum dots thin films incorporation with Au nanoparticles.

    PubMed

    Wang, Hongyu; Xu, Ling; Zhang, Renqi; Ge, Zhaoyun; Zhang, Wenping; Xu, Jun; Ma, Zhongyuan; Chen, Kunji

    2015-01-01

    Au nanoparticles (Au NPs)/CdTe/CdS QDs nanocomposite films were fabricated by deposition of Au NPs and layer-by-layer self-assembly of colloidal CdTe/CdS QDs. Photoluminescence (PL) spectra showed that Au NPs incorporation resulted in an increase of PL intensity about 16-fold compared with that of the samples without Au NPs. PL enhancement of Au NPs/CdTe/CdS QDs nanocomposite films can be controlled by tuning the thickness of spacer layer between the metal nanoparticles (MNPs) and QDs. Optical absorption spectra exhibited the incorporation of Au NPs boosted the absorption of Au NPs/CdTe/CdS QDs nanocomposite films. The results of finite-difference time-domain (FDTD) simulation indicated that the increased sizes of Au NPs resulted in stronger localization of electric field, which boosted the PL intensity of QDs in the vicinity of Au NPs. We thought that these were mainly attributed to localized SP enhancement effects of the Au NPs. Our experiment results demonstrated that Au NPs/QDs nanocomposite films would be a promising candidate for optoelectronic devices application. PACS 78.55.-m; 82.33.Ln; 68.65.Hb. PMID:25897301

  18. Phase transitions and domain structures of ferroelectric nanoparticles: Phase field model incorporating strong elastic and

    E-print Network

    Chen, Long-Qing

    Phase transitions and domain structures of ferroelectric nanoparticles: Phase field model Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing the ferroelectricity dis- appears for the nanowire and thin film are estimated to be around 1.4 nm. Vortex domain

  19. Study of the physicochemical properties of the BSA: flavonoid nanoparticle

    Microsoft Academic Search

    Ru Fang; Hao Jing; Zhi Chai; Guanghua Zhao; Serge Stoll; Fazheng Ren; Fei Liu; Xiaojing Leng

    2011-01-01

    A method to design a nanoparticle using bovine serum albumin and flavonoid was introduced in this work. Kaempferol and rutin\\u000a were used here as models of hydrophobic flavonoids. Bovine serum albumin molecules formed nanoparticle with diameter of X–30 nm,\\u000a promoted by dimethyl sulfoxide and flavonoid. The adsorption of kaempferol or rutin on bovine serum albumin was mainly hydrophobic,\\u000a particularly happened in

  20. Label-free capacitive immunosensor for microcystin-LR using self-assembled thiourea monolayer incorporated with Ag nanoparticles on gold electrode

    Microsoft Academic Search

    Suchera Loyprasert; Panote Thavarungkul; Punnee Asawatreratanakul; Booncharoen Wongkittisuksa; Chusak Limsakul; Proespichaya Kanatharana

    2008-01-01

    A label-free immunosensor based on a modified gold electrode incorporated with silver (Ag) nanoparticles (NPs) to enhance the capacitive response to microcystin-LR (MCLR) has been developed. Anti-microcystin-LR (anti-MCLR) was immobilized on silver nanoparticles bound to a self-assembled thiourea monolayer. Interaction of anti-MCLR and MCLR were directly detected by capacitance measurement. Under optimum conditions, MCLR could be determined with a detection

  1. Studies on the interactions of kaempferol to calcineurin by spectroscopic methods and docking.

    PubMed

    Lei, Hong; Qi, Yao; Jia, Zhi-Guang; Lin, Wei-Lin; Wei, Qun

    2009-08-01

    Kaempferol, in our previous study, was a new immunosuppressant on calcineurin (CN), the Ca(2+)/calmodulin (CaM)-dependent protein phosphatase. Here, we examined the interactions of kaempferol with CN by fluorescence spectroscopy (FS), circular dichroism spectroscopy (CD) and docking. Data of kaempferol with CN catalytic subunit (CN A) and its truncated mutant CNAa obtained by FS method showed that the binding stoichiometry of kaempferol/CN A was 1:1, catalytic domain of CN A was the concrete domain for kaempferol binding while other domains contributed a lot to this binding. Distances from kaempferol to each tryptophan (Trp) in CN A by energy transfer experiments and the subsequent docking study interestingly provided the same binding sites for kaempferol, which all located in the non-active site area of CN A catalytic domain, also consisted with our previous conclusion from CN activity assay. Furthermore, CD results showed a much tighter structure of CN A for the inhibitor binding; on the other hand, presence of Ca(2+) and Mn(2+) decreased kaempferol binding on CN A. PMID:19439201

  2. Protective effects of kaempferol on lipopolysaccharide-induced mastitis in mice.

    PubMed

    Cao, Rongfeng; Fu, Kaiqiang; Lv, Xiaopei; Li, Weishi; Zhang, Naisheng

    2014-10-01

    Kaempferol isolated from the root of Zingiberaceae plants galangal and other Chinese herbal medicines have been reported to have anti-inflammatory properties. However, the anti-inflammatory effects of kaempferol on lipopolysaccharide (LPS)-induced mastitis are unknown and their underlying molecular mechanisms remain to be explored. The aim of this study was to evaluate the effects of kaempferol on LPS-induced mouse mastitis. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. Kaempferol was injected 1 h before and 12 h after induction of LPS intraperitoneally. The present results showed that kaempferol markedly reduced infiltration of neutrophilic granulocyte, activation of myeloperoxidase (MPO), expression of tumor necrosis factor-? (TNF-?), interleukin-6 (IL-6), and interleukin-1? (IL-1?) in a dose-dependent manner, which were increased in LPS-induced mouse mastitis. Furthermore, kaempferol suppressed the phosphorylation of nuclear factor-?B (NF-?B) p65 subunit and the degradation of its inhibitor I?B?. All results suggest that anti-inflammatory effects of kaempferol against the LPS-induced mastitis possibly through inhibition of the NF-?B signaling pathway. Kaempferol may be a potential therapeutic agent for mastitis. PMID:24743918

  3. Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation.

    PubMed

    Liu, Zhen; Zhang, Zhongdong; Xing, Wei; Komarneni, Sridhar; Yan, Zifeng; Gao, Xionghou; Zhou, Xiaoping

    2014-01-01

    Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)(+) or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400?h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage. PMID:25328502

  4. Preparation and surface characterization of polymer nanoparticles designed for incorporation into hybrid materials.

    PubMed

    Fonseca, T; Relógio, P; Martinho, J M G; Farinha, J P S

    2007-05-01

    We prepared water dispersions of poly(n-butyl methacrylate-st-butyl acrylate) crosslinked core-shell nanoparticles functionalized with different amounts of trimethoxisilane (TMS) groups in the outer shell. The purpose of the TMS groups is to chemically bind the rubbery particles to a nanostructured silica network, using sol-gel copolymerization. Here, we present nanoparticles containing 13 mol % and 30 mol % of TMS groups in the outer shell and compare their surface morphology with particles that do not contain TMS. The particles are prepared by a two-step seeded emulsion polymerization technique at neutral pH. In the first step, we obtained crosslinked seed particles (44 nm in diameter) by a batch process. In the second step, we used a semi-continuous emulsion polymerization technique under starved feed conditions to obtain monodispersed particles of controlled composition and size (ca. 100 nm in diameter). Fluorescence decay measurements were performed in situ on the dispersions, using a pair of cationic dyes adsorbed onto the surface of the nanoparticles: rhodamine 6G as the energy transfer donor and malachite green carbinol hydrochloride as the acceptor. The kinetics of Förster resonance energy transfer (FRET) between the dyes is sensitive to the donor-acceptor distance, allowing us to obtain the binding distribution of the dyes at the nanoparticle surface. For the unmodified nanoparticles, we found a dye distribution that corresponds to an average interface thickness of delta = (5.2 +/- 0.2) nm. For the samples containing 13 mol % and 30 mol % of TMS groups in the outer shell we obtained broader interfaces, with widths of delta = (6.2 +/- 0.2) nm and delta = (6.5 +/- 0.1) nm respectively. This broadening of the distribution with the surface modification is interpreted in terms of the increase in free volume of the shell caused by the TMS groups. Finally, we studied the effect of temperature on the water-polymer interface fuzziness, in order to evaluate the accessibility of the TMS groups during the sol-gel synthesis of nanostructured hybrid materials. PMID:17417887

  5. Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of apolipoprotein E deficient mice

    SciTech Connect

    Xiao, Hong-Bo, E-mail: xhbzhb@yahoo.com [College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128 (China)] [College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128 (China); Lu, Xiang-Yang; Sun, Zhi-Liang [Hunan Agricultural University, Changsha 410128 (China)] [Hunan Agricultural University, Changsha 410128 (China); Zhang, Heng-Bo [Furong District Red Cross Hospital, Changsha 410126 (China)] [Furong District Red Cross Hospital, Changsha 410126 (China)

    2011-12-15

    Recent studies show that osteopontin (OPN) and its receptor cluster of differentiation 44 (CD44) are two pro-inflammatory cytokines contributing to the development of atherosclerosis. The objective of this study was to explore the inhibitory effect of kaempferol, a naturally occurring flavonoid compound, on atherogenesis and the mechanisms involved. The experiments were performed in aorta and plasma from C57BL/6J control and apolipoprotein E-deficient (ApoE{sup -/-}) mice treated or not with kaempferol (50 or 100 mg/kg, intragastrically) for 4 weeks. Kaempferol treatment decreased atherosclerotic lesion area, improved endothelium-dependent vasorelaxation, and increased the maximal relaxation value concomitantly with decrease in the half-maximum effective concentration, plasma OPN level, aortic OPN expression, and aortic CD44 expression in ApoE{sup -/-} mice. In addition, treatment with kaempferol also significantly decreased reactive oxygen species production in mice aorta. The present results suggest that kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. -- Graphical abstract: Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. Highlights: Black-Right-Pointing-Pointer OPN-CD44 pathway plays a critical role in the development of atherosclerosis. Black-Right-Pointing-Pointer We examine lesion area, OPN and CD44 changes after kaempferol treatment. Black-Right-Pointing-Pointer Kaempferol treatment decreased atherosclerotic lesion area in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol treatment decreased aortic OPN and CD44 expressions in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis.

  6. Improved photovoltaic performance of silicon nanowire/organic hybrid solar cells by incorporating silver nanoparticles.

    PubMed

    Liu, Kong; Qu, Shengchun; Zhang, Xinhui; Tan, Furui; Wang, Zhanguo

    2013-01-01

    Silicon nanowire (SiNW) arrays show an excellent light-trapping characteristic and high mobility for carriers. Surface plasmon resonance of silver nanoparticles (AgNPs) can be used to increase light scattering and absorption in solar cells. We fabricated a new kind of SiNW/organic hybrid solar cell by introducing AgNPs. Reflection spectra confirm the improved light scattering of AgNP-decorated SiNW arrays. A double-junction tandem structure was designed to manufacture our hybrid cells. Both short-circuit current and external quantum efficiency measurements show an enhancement in optical absorption of organic layer, especially at lower wavelengths. PMID:23418988

  7. Improved photovoltaic performance of silicon nanowire/organic hybrid solar cells by incorporating silver nanoparticles

    PubMed Central

    2013-01-01

    Silicon nanowire (SiNW) arrays show an excellent light-trapping characteristic and high mobility for carriers. Surface plasmon resonance of silver nanoparticles (AgNPs) can be used to increase light scattering and absorption in solar cells. We fabricated a new kind of SiNW/organic hybrid solar cell by introducing AgNPs. Reflection spectra confirm the improved light scattering of AgNP-decorated SiNW arrays. A double-junction tandem structure was designed to manufacture our hybrid cells. Both short-circuit current and external quantum efficiency measurements show an enhancement in optical absorption of organic layer, especially at lower wavelengths. PMID:23418988

  8. Study of incorporation of silver nanoparticles onto PE-g-PAAc nonwoven fabric by ?-irradiation for water treatment

    NASA Astrophysics Data System (ADS)

    Phu, Dang Van; Quoc, Le Anh; Duy, Nguyen Ngoc; Hien, Nguyen Quoc

    2013-07-01

    Polyethylene nonwoven (PE) fabric was grafted with acrylic acid (PE-g-PAAc) by the ?-ray pre-irradiation process. The effect of dose and acrylic acid concentration on the grafting degree was investigated. The dose of about 20-30 kGy, acrylic acid concentration of 20-30%, and the reaction time of about 2 h at ˜90 °C were selected as suitable parameters for grafting. The PE-g-PAAc fabric was then impregnated in colloidal silver nanoparticles (AgNPs) solution for incorporating AgNPs. The resultant PE-g-PAAc/AgNPs fabric containing ˜10,000 ppm AgNPs exhibits high antimicrobial activity (?>99%) against Escherichia coli in water. The release of silver into water filtrate determined by ICP-MS was less than 0.1 mg/L. The PE-g-PAAc/AgNPs fabric can be potentially applied for water and/or air treatment as an antimicrobial membrane filter.

  9. Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

    PubMed

    Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

    2015-10-15

    Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9mg/dL. PMID:25988995

  10. Hybrid organic-inorganic nanoparticles: controlled incorporation of gold nanoparticles into virus-like particles and application in surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Niebert, Marcus; Riches, James; Howes, Mark; Ferguson, Charles; Parton, Robert G.; Middelberg, Anton P. J.; Rintoul, Llew; Fredericks, Peter M.

    2007-01-01

    A capsid is the protein coat surrounding a virus' genome that ensures its protection and transport. The capsid of murine polyomavirus (muPy) consists of one major (VP1) and two minor (VP2/3) proteins, from which just VP1 is sufficient to form the capsid when expressed recombinantly (1). From a material engineering point of view, viral capsids are of interest because they present a paradigm for complex self-assembly on the nanometer scale. Understanding and controlling these assembly dynamics will allow the construction of nanoscale structures using a self-assembly process. The first step in this direction was the discovery that capsids of several viruses can be reversibly disassembled into their building blocks and reassembled using the same building blocks by simply changing the buffer conditions (2, 3). Such capsids already find applications as targeted in vivo delivery vectors for genes, proteins or small molecular drugs (4, 5), as optical probes for biomedical imaging and sensing purposes with unprecedented resolution and sensitivity and can potentially be used as templates for nanoelectronics (6, 7). Here we show the controlled incorporation of inorganic gold nanoparticles into the capsid shell of muPy. This incorporation is mediated by covalent sulfide bonds between the capsid proteins cysteine residues and the molecular gold. The number of incorporated gold particles can be controlled during the assembly process and the capsids retain their ability to transduce cells. These particles provide new tools for tracking of viral particles in cells, and simultaneously allow the delivery of genes packages in the hollow capsid.

  11. Long-lasting in vivo and in vitro antibacterial ability of nanostructured titania coating incorporated with silver nanoparticles.

    PubMed

    Cheng, Hao; Li, Yong; Huo, Kaifu; Gao, Biao; Xiong, Wei

    2014-10-01

    Although titanium (Ti) implants are widely used clinically, implant-associated bacterial infection is still one of the most serious complications in orthopedic surgery. Long-term antibacterial properties and the ability to inhibit biofilm formation are highly desirable to prevent implant associated infection. In this study, a controllable amount of silver (Ag) nanoparticles was incorporated into titanium oxide; or titanium, nanotubes (TiO? -NTs). The reliable release and long-term antibacterial function of Ag, in vivo and in vitro, and influence normal bone-implant integration from the Ag released from Ag-incorporated NTs in vivo have been studied to make them useable in clinical practice. In the current study, TiO? -NTs loaded with Ag (NT-Ag) exhibited strong antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300) in vitro for 30 days, and the ability to penetrate the protein layer well. In addition, X-ray examination and 2-[(18)F]-fiuoro-2-deoxy-D-glucose positron emission tomography indicates that NT-Ag show extremely long antibacterial activity in vivo in a rat model. Furthermore, histomorphometric analysis demonstrated that satisfactory bio-integration can be expected. Our results indicate that NT-Ag has both simultaneous antimicrobial and excellent bio-integration properties, make it a promising therapeutic material for orthopedic application. PMID:24178451

  12. Enhancement the oral bioavailability of praziquantel by incorporation into solid lipid nanoparticles.

    PubMed

    Yang, Li; Geng, Yehui; Li, Hao; Zhang, Yu; You, Jinsong; Chang, Yanyan

    2009-02-01

    The aim of this study was to assess the feasibility of solid lipid nanoparticles (SLN) to enhance the oral bioavailability of praziquantel (PZQ). SLN loaded with PZQ were produced by ultrasound technique. The characteristics of PZQ-SLN were studied in detail. The concentration of PZQ in plasma was determined using reversed-phase high-performance liquid chromatography after oral administration of PZQ-SLN and control PZQ tablets (PZQ-TAB) in rats respectively. The results showed that PZQ-SLN had an average diameter 110 nm with Zeta potential of -66.3 mV. The encapsulation efficiency of PZQ was about 80%. In vitro drug release fitted the Weibull distribution equation. There were two peaks in the PZQ concentration-time curves in plasma after oral administration of PZQ-SLN. The first peak might be caused by free drug and that adsorbed onto the surface of PZQ-SLN. The second peak was indicative of gut uptake of PZQ-SLN. The AUC(0-infinity) value of PZQ after oral administration of SLN was 4.1 fold higher than that obtained with the PZQ-TAB. The MRT of PZQ-SLN was also significantly enhanced, resulting in an about twofold increase compared with PZQ-TAB. Thus, the oral bioavailability of PZQ-SLN increased significantly compared to PZQ-TAB, and the results indicate that SLN can be a promising drug carrier for PZQ. PMID:19320279

  13. Kaempferol inhibits VEGF expression and in vitro angiogenesis through a novel ERK-NF?B-cMyc-p21 pathway

    PubMed Central

    Luo, Haitao; Rankin, Gary O.; Juliano, Noelle; Jiang, Bing-Hua; Chen, Yi Charlie

    2011-01-01

    Kaempferol has been reported to reduce the risk of ovarian cancer, but the mechanism is not completely understood. In this study, we tend to expand our understanding on how kaempferol regulates VEGF expression and angiogenesis in ovarian cancer cells. We timed VEGF secretion, and studied in-vitro angiogenesis by kaempferol treatment. Gene expression was examined by qRT-PCR, ELISA, Western Blotting, or luciferase assay, and pathways were examined by manipulating genetic components with plasmid or siRNA transfection. It was found that kaempferol time-dependently inhibited VEGF secretion, and suppressed in-vitro angiogenesis. Kaempferol down-regulated ERK phosphorelation as well as NF?B and cMyc expression, but promoted p21 expression. Examination of relationship between these genes suggested a novel ERK-NF?B-cMyc-p21-VEGF pathway, which accounts for kaempferol’s angioprevention effects in ovarian cancer cells. This data supplements our comprehension of the mechanisms behind kaempferol’s biological influence in ovarian cancer cells, and better characterized kaempferol toward chemoprevention. PMID:21927533

  14. Evolution of structural and physical properties upon annealing of sputter-deposited Zr0.84Y0.16-O2 films incorporating copper and palladium nanoparticles

    Microsoft Academic Search

    D. I. Zakharov; D. Horwat; J. L. Endrino; F. Capon; J. F. Pierson

    2009-01-01

    Me-incorporated Zr0.84Y0.16 oxide thin films (Me: Cu or Pd) were synthesized by magnetron co-sputtering. The film structural evolution due to metal content increase was shown: Me-doped nanocrystalline yttria stabilized zirconia (YSZ); Me-doped amorphous oxide; metal nanoparticles embedded in the amorphous oxide matrix. Annealing for 2 h at 300°C in air promoted copper oxide formation and the segregation of very fine

  15. Antioxidant activities of curcumin and ascorbyl dipalmitate nanoparticles and their activities after incorporation into cellulose-based packaging films.

    PubMed

    Sonkaew, Piyapong; Sane, Amporn; Suppakul, Panuwat

    2012-05-30

    Curcumin (Ccm) and ascorbyl dipalmitate (ADP) nanoparticles (NPs) with average sizes of ?50 and ?80 nm, respectively, were successfully produced by rapid expansion of subcritical solutions into liquid solvents (RESOLV). Pluronic F127 was employed as a stabilizer for both Ccm- and ADP-NPs in an aqueous receiving solution. Antioxidant activities of the Ccm-NPs and ADP-NPs were subsequently investigated using four assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ABTS radical cation decolorization, ?-carotene bleaching, and ferric reducing antioxidant power. Ccm-NPs and ADP-NPs showed higher antioxidant activities than those of Ccm and ADP. Ccm-NPs yielded higher antioxidant activities than those of Ccm in ethanol and water (Ccm-EtOH and Ccm-H(2)O), respectively. ADP-NPs yielded lower antioxidant activities than that of ADP in ethanol (ADP-EtOH) but higher activities than that of ADP in water (ADP-H(2)O). Moreover, incorporation of Ccm-NPs and ADP-NPs into cellulose-based films indicated that Ccm-NPs and ADP-NPs significantly enhanced the antioxidant activities of Ccm and ADP (p < 0.05). Our results show that the environmentally benign supercritical CO(2) technique should be generally applicable to NP fabrication of other important bioactive ingredients, especially in liquid form. In addition, we suggest that Ccm-NPs and ADP-NPs can be used to reduce the dosage of Ccm and ADP and improve their bioavailability, and thus merit further investigation for antioxidant packaging film and coating applications. PMID:22583595

  16. Production of kaempferol 3-O-rhamnoside from glucose using engineered Escherichia coli.

    PubMed

    Yang, So-Mi; Han, So Hyun; Kim, Bong-Gyu; Ahn, Joong-Hoon

    2014-08-01

    Flavonoids are ubiquitous phenolic compounds and at least 9,000 have been isolated from plants. Most flavonoids have been isolated and assessed in terms of their biological activities. Microorganisms such as Escherichia coli and Saccharomyces cerevisiae are efficient systems for the synthesis of flavonoids. Kaempferol 3-O-rhamnoside has notable biological activities such as the inhibition of the proliferation of breast cancer cells, the absorption of glucose in the intestines, and the inhibition of the self-assembly of beta amyloids. We attempted to synthesize kaempferol 3-O-rhamnoside from glucose in E. coli. Five flavonoid biosynthetic genes [tyrosine ammonia lyase (TAL), 4-coumaroyl CoA ligase (4CL), chalcone synthase (CHS), flavonol synthase (FLS), and flavonol 3-O-rhamnosyltransferase (UGT78D1)] from tyrosine were introduced into E. coli that was engineered to increase tyrosine production. By using this approach, the production of kaempferol 3-O-rhamnoside increased to 57 mg/L. PMID:24879482

  17. One-pot synthesis of platinum-based nanoparticles incorporated into mesoporous niobium oxide-carbon composites for fuel cell electrodes.

    PubMed

    Orilall, M Christopher; Matsumoto, Futoshi; Zhou, Qin; Sai, Hiroaki; Abruña, Héctor D; DiSalvo, Francis J; Wiesner, Ulrich

    2009-07-01

    Catalyst-electrode design is crucial for the commercialization and widespread use of polymer electrolyte membrane fuel cells. There are considerable challenges in making less expensive, more durable, and more active catalysts. Herein, we report the one-pot synthesis of Pt and Pt-Pb nanoparticles incorporated into the pores of mesoporous niobium oxide-carbon composites. The self-assembly of block copolymers with niobium oxide and metal precursors results in an ordered mesostructured hybrid. Appropriate heat treatment of this hybrid produces highly crystalline, well-ordered mesoporous niobium oxide-carbon composites with Pt (or Pt-Pb) nanoparticles incorporated into the mesopores. The in situ-generated graphitic-like carbon material prevents the collapse of the mesostructure, while the metal oxide crystallizes at high temperatures and enhances the electrical conductivity of the final material. Formic acid electrooxidation with this novel material shows 4 times higher mass activities (3.3 mA/microg) and somewhat lower onset potentials (-0.24 V vs Ag/AgCl) than the best previously reported values employing Pt-Pb intermetallic nanoparticles supported on conducting carbon (0.85 mA/microg and -0.18 V, respectively). PMID:19566103

  18. Catalyzed radical polymerization of styrene vapor on nanoparticle surfaces and the incorporation of metal and metal oxide nanoparticles within polystyrene polymers.

    PubMed

    Abdelsayed, Victor; Alsharaeh, Edreese; El-Shall, M Samy

    2006-10-01

    We present a novel approach to polymerize olefin vapors on the surfaces of metallic and semiconductor nanoparticles. In this approach, a free radical initiator such as AIBN is dissolved in a volatile solvent such as acetone. Selected nanoparticles (prepared separately using the laser vaporization-controlled condensation method) are used to form initiator-coated nanoparticles placed on a glass substrate. The olefin (styrene) vapor is polymerized by the thermally activated initiator on the nanoparticle surfaces. Our approach also provides structural and mechanistic information on the early stages of catalyzed gas-phase polymerization, which can be used to correlate the gas-phase structural properties with the bulk properties and the performance of the polymer nanocomposites. This correlation is the key step in controlling the properties of the polymer nanocomposites. Our results clearly demonstrate the success of this method in preparing polymer coated nanoparticles for a variety of interesting applications. The precise control of the chemical functionality, thickness, and morphology of the polymer film and the size, size distribution, and properties of the core nanoparticles (photoluminescence, magnetic) may lead to major technological breakthroughs in a variety of applications including drug delivery, ultrasensitive detectors, and chemical and biological sensors. PMID:17004754

  19. Evolution of structural and physical properties upon annealing of sputter-deposited Zr0.84Y0.16-O2 films incorporating copper and palladium nanoparticles

    NASA Astrophysics Data System (ADS)

    Zakharov, D. I.; Horwat, D.; Endrino, J. L.; Capon, F.; Pierson, J. F.

    2009-09-01

    Me-incorporated Zr0.84Y0.16 oxide thin films (Me: Cu or Pd) were synthesized by magnetron co-sputtering. The film structural evolution due to metal content increase was shown: Me-doped nanocrystalline yttria stabilized zirconia (YSZ); Me-doped amorphous oxide; metal nanoparticles embedded in the amorphous oxide matrix. Annealing for 2 h at 300°C in air promoted copper oxide formation and the segregation of very fine Pd particles. XANES analysis at the Cu-K edge showed that Cu is bonded to oxygen and Zr(Y) in Cu-doped amorphous oxide; this state was not affected by the thermal treatment. XANES and resistivity analyses indicated that the Cu nanoparticles likely have oxidized surfaces while the Pd-containing films showed only minor chemical changes after annealing.

  20. The effects of curing medium on flexural strength and water permeability of concrete incorporating TiO 2 nanoparticles

    Microsoft Academic Search

    Ali Nazari

    2011-01-01

    The effect of limewater on flexural strength and water permeability of TiO2 nanoparticles binary blended concrete has been investigated. TiO2 nanoparticles with partial replacement of cement by 0.5, 1.0, 1.5 and 2.0 weight percent have been used as reinforcement.\\u000a Curing of the specimens has been carried out in water and saturated limewater for 7, 28 and 90 days after casting. The

  1. Hepatocyte growth factor incorporated chitosan nanoparticles augment the differentiation of stem cell into hepatocytes for the recovery of liver cirrhosis in mice

    Microsoft Academic Search

    Sivasami Pulavendran; Chellan Rose; Asit Baran Mandal

    2011-01-01

    Background  Short half-life and low levels of growth factors in the niche of injured microenvironment necessitates the exogenous and sustainable\\u000a delivery of growth factors along with stem cells to augment the regeneration of injured tissues.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Here, recombinant human hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionic gelation\\u000a method and studied for its morphological and physiological characteristics. Cirrhotic

  2. Kaempferol 7- O-rhamnoside-4?- O-glucoside from Pteridium aquilinum

    Microsoft Academic Search

    Filippo Imperato

    1998-01-01

    A new flavonol glycoside from aerial parts of Pteridium aquilinum was identified as kaempferol 7-O-rhamnoside-4?-O-glucoside by chemical and spectral methods. In addition a mixture of quercetin 3-O-fructoside and isoquercitrin was found in this plant material.

  3. Antidepressant-like Effect of Kaempferol and Quercitirin, Isolated from Opuntia ficus-indica var. saboten

    PubMed Central

    Park, Soo-Hyun; Sim, Yun-Beom; Han, Pyung-Lim; Lee, Jin-Koo

    2010-01-01

    Opuntia ficus-indica var. saboten. is widely cultivated in Jeju Island (South Korea) for use in manufacture of health foods. This study described antidepressant effect of two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. The expression of the hypothalamic POMC mRNA or plasma ?-endorphin levels were increased by extract of Opuntia ficus-indica var. saboten or its flavoniods administered orally. In addition, antidepressant activity was studied using tail suspension test (TST), forced swimming test (FST) and rota-rod test in chronically restraint immobilization stress group in mice. After restraint stress (2 hrs/day for 14 days), animals were kept in cage for 14 days without any further stress, bet with drugs. Mice were fed with a diet supplemented for 14 days and during the behavioral test period with kaempferol or quercitrin (30 mg/kg/day). POMC mRNA or plasma ?-endorphin level was increased by extract of Opuntia ficus-indica var. saboten and its flavoniods. In addition, immobility time in TST and FST was significantly reduced by kaempferol or quercitrin. In rota-rod test, the time of permanence was maintained to the semblance of control group in turning at 15 rpm. Our results suggest that two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. show a potent antidepressant effect. PMID:22110339

  4. Inhibition of Staphylococcus aureus PriA Helicase by Flavonol Kaempferol.

    PubMed

    Huang, Yen-Hua; Huang, Chien-Chih; Chen, Cheng-Chieh; Yang, Kai-Jr; Huang, Cheng-Yang

    2015-06-01

    Staphylococcus aureus is an important etiological agent responsible for healthcare-associated infections. In this study, the effect of flavonoids on the inhibition of S. aureus PriA (SaPriA), an essential helicase for DNA replication restart, which is critical for bacterial survival, was investigated. Using vanadate-sensitive colorimetric assay, the concentration of phosphate, from ATP hydrolysis by SaPriA, was decreased to 37 and 69 %, respectively, in the presence of 35 ?M kaempferol and myricetin. The effect of quercetin, galangin, dihydromyricetin, and myricitrin was insignificant. From titration curve, IC50 of kaempferol for SaPriA was determined to be 22 ± 2 ?M. Using fluorescence quenching, we identified that kaempferol can bind to SaPriA with K d of 9.1 ± 3.2 ?M. To our knowledge, these preliminary results constituted the first study regarding that naturally occurring product such as flavonols kaempferol and myricetin can be potent inhibitors targeting PriA. PMID:25894858

  5. Kaempferol Induces Cell Death Through ERK and Akt-Dependent Down-Regulation of XIAP and Survivin in Human Glioma Cells

    Microsoft Academic Search

    Ji Cheon Jeong; Min Soo Kim; Thae Hyun Kim; Yong Keun Kim

    2009-01-01

    The present study was undertaken to determine the molecular mechanism by which kaempferol induces cell death in human glioma\\u000a cells. Kaempferol resulted in loss of cell viability and inhibition of proliferation in a dose- and time-dependent manner,\\u000a which were largely attributed to cell death. Kaempferol caused an increase in reactive oxygen species (ROS) generation and\\u000a the kaempferol-induced cell death was

  6. Optimizing stem cell functions and antibacterial properties of TiO2 nanotubes incorporated with ZnO nanoparticles: experiments and modeling

    PubMed Central

    Liu, Wenwen; Su, Penglei; Gonzales, Arthur; Chen, Su; Wang, Na; Wang, Jinshu; Li, Hongyi; Zhang, Zhenting; Webster, Thomas J

    2015-01-01

    To optimize mesenchymal stem cell differentiation and antibacterial properties of titanium (Ti), nano-sized zinc oxide (ZnO) particles with tunable concentrations were incorporated into TiO2 nanotubes (TNTs) using a facile hydrothermal strategy. It is revealed here for the first time that the TNTs incorporated with ZnO nanoparticles exhibited better biocompatibility compared with pure Ti samples (controls) and that the amount of ZnO (tailored by the concentration of Zn(NO3)2 in the precursor) introduced into TNTs played a crucial role on their osteogenic properties. Not only was the alkaline phosphatase activity improved to about 13.8 U/g protein, but the osterix, collagen-I, and osteocalcin gene expressions was improved from mesenchymal stem cells compared to controls. To further explore the mechanism of TNTs decorated with ZnO on cell functions, a response surface mathematical model was used to optimize the concentration of ZnO incorporation into the Ti nanotubes for stem cell differentiation and antibacterial properties for the first time. Both experimental and modeling results confirmed (R2 values of 0.8873–0.9138 and 0.9596–0.9941, respectively) that Ti incorporated with appropriate concentrations (with an initial concentration of Zn(NO3)2 at 0.015 M) of ZnO can provide exceptional osteogenic properties for stem cell differentiation in bone cells with strong antibacterial effects, properties important for improving dental and orthopedic implant efficacy. PMID:25792833

  7. Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating Plasmonic Effects of Spheroidal Metallic Nanoparticles

    E-print Network

    Park, Namkyoo

    Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating be exploited to achieve efficient harvesting of solar energy. Notably, the incorporation of plasmonic effects can allow the light harvesting capability of a solar cell to be maintained even as the thickness

  8. Negative regulation of adipogenesis by kaempferol, a component of Rhizoma Polygonati falcatum in 3T3-L1 cells.

    PubMed

    Park, Ui-Hyun; Jeong, Ji-Cheon; Jang, Jae-Sik; Sung, Mi-Ran; Youn, HyeSook; Lee, Sook-Jeong; Kim, Eun-Joo; Um, Soo-Jong

    2012-01-01

    Rhizoma Polygonati falcatum (RPF) has been used as a traditional herbal medicine in Asia, because of its anti-hyperglycemic, anti-triglycemic, and anti-tumor activity. In this study, we determined the anti-adipogenic potential of RPF extract and its component kaempferol in 3T3-L1 adipocytes, and the underlying molecular mechanism(s) using microarray analysis. Adipocyte differentiation of 3T3-L1 cells was significantly impaired by RPF extract and kaempferol as monitored by Oil Red O staining and quantitative measurement of lipid accumulation. Additionally, the mRNA expression of adipogenesis genes decreased on treatment with kaempferol. The role of kaempferol at the genome-wide level was further assessed by a microarray approach. Our analysis indicated that kaempferol decreased the expression of adipogenic transcription factors (Ppar?, Cebp?, Srebp1, Rxr?, Lxr?, Ror?) and genes involved in triglyceride biosynthesis (Gpd1, Agpat2, Dgat2), while increasing lipolysis-related genes, such as Tnf?, Lsr, and Cel. Finally, co-transfection assays using luciferase reporter gene and reverse transcription-polymerase chain reaction (RT-PCR) analysis using peroxisome proliferator-activated receptor-? (PPAR?) target genes indicated that kaempferol significantly repressed rosiglitazone-induced PPAR? transcriptional activity. Overall, our data suggests that kaempferol, a major component of RPF, may be beneficial in obesity, by reducing adipogenesis and balancing lipid homeostasis partly through the down-regulation of PPAR?. PMID:22975504

  9. Sustained release of PTX-incorporated nanoparticles synergized by burst release of DOX?HCl from thermosensitive modified PEG/PCL hydrogel to improve anti-tumor efficiency.

    PubMed

    Xu, Shuxin; Wang, Weiwei; Li, Xijing; Liu, Jianping; Dong, Anjie; Deng, Liandong

    2014-10-01

    As drug therapies become increasingly sophisticated, the synergistic benefits of two or more drugs are often required. In this study, we aimed at improving anti-tumor efficiency of paclitaxel (PTX)-incorporated thermo-sensitive injectable hydrogel by the synergy of burst release of doxorubicin hydrochloride (DOX?HCl). Thermosensitive injectable hydrogel composed of nanoparticles assembled from amphiphilic copolymer poly(?-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(?-caprolaone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT) was fabricated. Hydrophobic PTX and hydrophilic DOX?HCl were loaded simultaneously in the thermo-sensitive injectable hydrogel by a two-stage entrapment. Thermosensitive gelling behaviors of drug-loading PECT nanoparticle aqueous dispersions were studied. In vitro release profiles of PTX and DOX?HCl and in vivo anti-tumor effect by dual drugs from PECT hydrogel were investigated. The results showed that hydrophilic and hydrophobic drugs could be successfully entrapped in PECT hydrogel simultaneously without affecting its thermo-sensitive behavior. In vitro release profiles demonstrated the burst release of DOX?HCl and the sustained release of PTX. Anti-tumor effect was improved by a fast and tense attack caused by the burst release of hydrophilic DOX?HCl from hydrogel, which was continued by the sequent sustained release of PTX-incorporated nanoparticles and remnant DOX?HCl. Unintentionally, entrapped in PECT hydrogel, hydrophilic DOX?HCl was observed to have a sustained releasing pattern in vitro and in vivo. PMID:24931190

  10. Development of Nanoparticles Incorporating a Novel Liposomal Membrane Destabilization Peptide for Efficient Release of Cargos into Cancer Cells

    PubMed Central

    Ohgita, Takashi; Kogure, Kentaro

    2014-01-01

    In anti-cancer therapy mediated by a nanoparticle-based drug delivery system (DDS), overall efficacy depends on the release efficiency of cargos from the nanoparticles in the cancer cells as well as the specificity of delivery to tumor tissue. However, conventional liposome-based DDS have no mechanism for specifically releasing the encapsulated cargos inside the cancer cells. To overcome this barrier, we developed nanoparticles containing a novel liposomal membrane destabilization peptide (LMDP) that can destabilize membranes by cleavage with intramembranous proteases on/in cancer cells. Calcein encapsulated in liposomes modified with LMDP (LMDP-lipo) was effectively released in the presence of a membrane fraction containing an LMDP-cleavable protease. The release was inhibited by a protease inhibitor, suggesting that LMDP-lipo could effectively release its cargo into cells in response to a cancer-specific protease. Moreover, when LMDP-lipo contained fusogenic lipids, the release of cargo was accelerated, suggesting that the fusion of LMDP-lipo with cellular membranes was the initial step in the intracellular delivery. Time-lapse microscopic observations showed that the release of cargo from LMDP-lipo occurred immediately after association of LMDP-lipo with target cells. Consequently, LMDP-lipo could be a useful nanoparticle capable of effective release of cargos specifically into targeted cancer cells. PMID:25343714

  11. Regulation of heme oxygenase-1 expression and MAPK pathways in response to kaempferol and rhamnocitrin in PC12 cells

    SciTech Connect

    Hong, J.-T. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Yen, J.-H. [Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan (China); Wang Lisu [Department of Food Science and Technology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Department of Environmental and Occupational Health, Medical College, Cheng-Kung University, Tainan 701, Taiwan (China); Lo, Y.-H. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Chen, Z.-T. [Department of Medicinal Chemistry, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Wu, M.-J. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China)], E-mail: imwu@mail.chna.edu.tw

    2009-05-15

    Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities, especially neural diseases. Our aim of research is to investigate the protective effects and mechanisms of kaempferol and rhamnocitrin (kaempferol-7-methyl ether) on oxidative damage in rat pheochromocytoma PC12 cells induced by a limited supply of serum and hydrogen peroxide (H{sub 2}O{sub 2}). The current result demonstrated that kaempferol protected PC12 cells from serum deprivation-induced apoptosis. Pretreatment of cells with kaempferol also diminished intracellular generation of reactive oxygen species (ROS) in response to H{sub 2}O{sub 2} and strongly elevated cell viability. RT-Q-PCR and Western blotting revealed that kaempferol and rhamnocitrin significantly induced heme oxygenase (HO)-1 gene expression. Addition of zinc protoporphyrin (Znpp), a HO-1 competitive inhibitor, significantly attenuated their protective effects in H{sub 2}O{sub 2}-treated cells, indicating the vital role of HO-1 in cell resistance to oxidative injury. While investigating the signaling pathways responsible for HO-1 induction, we observed that kaempferol induced sustained extracellular signal-regulated protein kinase 1/2 (ERK1/2) in PC12 cells grown in low serum medium; while rhamnocitrin only stimulated transient ERK cascade. Addition of U0126, a highly selective inhibitor of MEK1/2, which is upstream of ERK1/2, had no effect on kaempferol- or rhamnocitrin-induced HO-1 mRNA expression, indicating no direct cross-talk between these two pathways. Furthermore, both kaempferol and rhamnocitrin were able to persistently attenuate p38 phosphorylation. Taking together, the above findings suggest that kaempferol and rhamnocitrin can augment cellular antioxidant defense capacity, at least in part, through regulation of HO-1 expression and MAPK signal transduction.

  12. Kaempferol Promotes Transplant Tolerance by Sustaining CD4+FoxP3+ Regulatory T Cells in the Presence of Calcineurin Inhibitor.

    PubMed

    Zeng, Y Q; Liu, X S; Wu, S; Zou, C; Xie, Q; Xu, S M; Jin, X W; Li, W; Zhou, A; Dai, Z

    2015-07-01

    Calcineurin inhibitor cyclosporine is widely used as an immunosuppressant in clinic. However, mounting evidence has shown that cyclosporine hinders tolerance induction by dampening Tregs. Therefore, it is of paramount importance to overcome this pitfall. Kaempferol was reported to inhibit DC function. Here, we found that kaempferol delayed islet allograft rejection. Combination of kaempferol and low-dose, but not high-dose, of cyclosporine induced allograft tolerance in majority of recipient mice. Although kaempferol plus either dose of cyclosporine largely abrogated proliferation of graft-infiltrating T cells and their CTL activity, both proliferation and CTL activity in mice treated with kaempferol plus low-dose, but not high-dose, cyclosporine reemerged rapidly upon treatment withdrawal. Kaempferol increased CD4+FoxP3+ Tregs both in transplanted mice and in vitro, likely by suppressing DC maturation and their IL-6 expression. Reduction in Tregs by low dose of cyclosporine was reversed by kaempferol. Kaempferol-induced Tregs exhibited both allospecific and non-allospecific suppression. Administering IL-6 abrogated allograft tolerance induced by kaempferol and cyclosporine via diminishing CD4+FoxP3+ Tregs. Thus, for the first time, we demonstrated that kaempferol promotes transplant tolerance in the presence of low dose of cyclosporine, which allows for sufficient Treg generation while minimizing side effects, resulting in much-needed synergy between kaempferol and cyclosporine. PMID:25808405

  13. Incorporation of cobalt-ferrite nanoparticles into a conducting polymer in aqueous micellar medium: strategy to get photocatalytic composites.

    PubMed

    Endr?di, Balázs; Hursán, Dorottya; Petrilla, Liliána; Bencsik, Gábor; Visy, Csaba; Chams, Amani; Maslah, Nabiha; Perruchot, Christian; Jouini, Mohamed

    2014-01-01

    In this study an easy strategy for conducting polymer based nanocomposite formation is presented through the deposition of cobalt-ferrite (CoFe(2)O(4)) containing poly(3,4-ethylenedioxythiophene) (PEDOT) thin layers. The electrochemical polymerization has been performed galvanostatically in an aqueous micellar medium in the presence of the nanoparticles and the surface active Triton X-100. The nanoparticles have been characterized by Transmission electron microscopy (TEM), the thin layers has been studied by applying Scanning electron microscopy (SEM), and X-ray diffraction (XRD), and the basic electrochemical properties have been also determined. Moreover, electrocatalytic activity of the composite was demonstrated in the electrooxidation reaction of dopamine (DA). The enhanced sensitivity - related to the cobalt-ferrite content - and the experienced photocatalyitic activity are promising for future application. PMID:25125121

  14. Characterization of Silicon Nanoparticles Formed from a Fluidized Bed Reactor and Their Incorporation onto Metal-Coated Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Zbib, Mohamad B.; Sahaym, Uttara; Bahr, David F.

    2014-01-01

    Enhancing the light trapping using nonwoven arrays of fibers has the potential to improve the photocurrent of silicon solar cells. In this work, amorphous and crystalline Si nanopowders (30-300 nm) were embedded in carbon fibers and fixed in place with electrodeposited nickel. Scanning and transmission electron microscopy techniques have been used to study the morphology of the Si particles and their interactions with the coatings. Two types of nanoparticles are identified, homogeneous nucleated particles (amorphous particles with some crystalline regions) and attrition particles (mostly crystalline products formed from fracture of particles as they grow in a fluidized bed reactor). Using the Brunauer-Emmett-Teller (BET) technique, the surface area and the pore diameter of these agglomerated Si nanoparticles were calculated to be 6.4 m2/g and 9.8 nm, respectively. After embedding the Si particles into the carbon matrix with the metal coatings, the electrical resistivity decreases, suggesting it is possible to enhance the light extraction of silicon solar cells using Si nanoparticles.

  15. The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

    SciTech Connect

    Mylonis, Ilias; Lakka, Achillia; Tsakalof, Andreas [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece) [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece); Simos, George, E-mail: simos@med.uth.gr [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece) [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece)

    2010-07-16

    Research highlights: {yields} Kaempferol inhibits HIF-1 activity in hepatocarcinoma cells; {yields} Kaempferol causes cytoplasmic mislocalization of HIF-1{alpha} by impairing the MAPK pathway. {yields} Viability of hepatocarcinoma cells under hypoxia is reduced by kaempferol. -- Abstract: Hepatocellular carcinoma (HCC) is characterized by high mortality rates and resistance to conventional treatment. HCC tumors usually develop local hypoxia, which stimulates proliferation of cancer cells and renders them resilient to chemotherapy. Adaptation of tumor cells to the hypoxic conditions depends on the hypoxia-inducible factor 1 (HIF-1). Over-expression of its regulated HIF-1{alpha} subunit, an important target of anti-cancer therapy, is observed in many cancers including HCC and is associated with severity of tumor growth and poor patient prognosis. In this report we investigate the effect of the dietary flavonoid kaempferol on activity, expression levels and localization of HIF-1{alpha} as well as viability of human hepatoma (Huh7) cancer cells. Treatment of Huh7 cells with kaempferol under hypoxic conditions (1% oxygen) effectively inhibited HIF-1 activity in a dose-dependent manner (IC{sub 50} = 5.16 {mu}M). The mechanism of this inhibition did not involve suppression of HIF-1{alpha} protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC{sub 50} = 4.75 {mu}M). Exposure of Huh7 cells to 10 {mu}{Mu} kaempferol caused significant reduction of their viability, which was remarkably more evident under hypoxic conditions. In conclusion, kaempferol, a non-toxic natural food component, inhibits both MAPK and HIF-1 activity at physiologically relevant concentrations (5-10 {mu}M) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent.

  16. The role of size and coating in Au nanoparticles incorporated into bi-component polymeric thin-film transistors.

    PubMed

    Mosciatti, Thomas; Orgiu, Emanuele; Raimondo, Corinna; Samorì, Paolo

    2014-05-21

    We describe the effect of blending poly(3-hexylthiophene) (P3HT) with Au nanoparticles (AuNPs) on the performance of organic thin-film transistors. To this end we have used AuNPs of two different sizes coated with chemisorbed SAMs of oligophenyl-thiols possessing increasing lengths. The electrical characteristics of the hybrid materials revealed changes in the field-effect mobility depending primarily on the AuNP size, as a result of the variable energy level of the coated metallic nanocluster and by the degree of modification of the P3HT crystalline structure. PMID:24604238

  17. In vitro availability of kaempferol glycosides from cream formulations of methanolic extract of the leaves of Melilotus elegans.

    PubMed

    Gebre-Mariam, Tsige; Asres, Kaleab; Getie, Melkamu; Endale, Abebe; Neubert, Reinhard; Schmidt, Peter C

    2005-05-01

    In Ethiopian traditional medicine, Melilotus elegans Salzm. ex Ser. (Leguminosae) is used for the treatment of haemorrhoids and lacerated wounds. In view of its wide spread use and proven anti-inflammatory activity, 80% methanolic extract of the leaves was formulated into creams. HPLC/UV and MS studies revealed the presence of flavonoids, of which kaempferol was the major aglycone. Quantitative estimation of kaempferol in the hydrolyzed extract as determined by HPLC/UV was found to be 16.3+/-0.93 microg/mg (n=6, range) of extract. The in vitro release profiles of kaempferol glycosides (quantified as kaempferol equivalent) from the cream formulations in a multilayer membrane system indicated that a lipophilic cream of the extract provides higher release of kaempferol glycosides than hydrophilic and amphiphilic ones. Over a study period of 4h, the lipophilic cream released 66+/-5.70% of kaempferol glycosides, while the hydrophilic and amphiphilic creams resulted in 55+/-2.77 and 38+/-2.30% release, respectively. PMID:15848053

  18. In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

    2014-06-01

    This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30 nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3-/I- redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs.

  19. In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells.

    PubMed

    Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

    2014-01-01

    This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30 nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I?(-)/I(-) redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs. PMID:24930387

  20. In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells

    PubMed Central

    Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

    2014-01-01

    This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30?nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3?/I? redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs. PMID:24930387

  1. In Vitro Biocompatibility and Antibacterial Efficacy of a Degradable Poly(L-lactide-co-epsilon-caprolactone) Copolymer Incorporated with Silver Nanoparticles

    PubMed Central

    Samberg, Meghan E.; Mente, Peter; He, Ting; King, Martin W.; Monteiro-Riviere, Nancy A.

    2014-01-01

    Silver nanoparticles (Ag-nps) are currently used as a natural biocide to prevent undesired bacterial growth in clothing, cosmetics and medical products. The objective of the study was to impart antibacterial properties through the incorporation of Ag-nps at increasing concentrations to electrospun degradable 50:50 poly(L-lactide-co-epsilon-caprolactone) scaffolds for skin tissue engineering applications. The biocompatibility of the scaffolds containing Ag-nps was evaluated with human epidermal keratinocytes (HEK); cell viability and proliferation were evaluated using Live/Dead and alamarBlue viability assays following 7 and 14 days of cell culture on the scaffolds. Significant decreases in cell viability and proliferation were noted for the 1.0 mg(Ag) g(scaffold)?1 after 7 and 14 days on Ag-nps scaffolds. After 14 days, scanning electron microscopy revealed a confluent layer of HEK on the surface of the 0.0 and 0.1 mg(Ag) g(scaffold)?1. Both 0.5 and 1.0 mg(Ag) g(scaffold)?1 were capable of inhibiting both Gram positive and negative bacterial strains. Uniaxial tensile tests revealed a significant (p < 0.001) decrease in the modulus of elasticity following Ag-nps incorporation compared to control. These findings suggest that a scaffold containing between 0.5 and 1.0 mg(Ag) g(scaffold)?1 is both biocompatible and antibacterial, and is suitable for skin tissue engineering graft scaffolds. PMID:24150238

  2. Influence of Cd2+/S2- molar ratio and of different capping environments in the optical properties of CdS nanoparticles incorporated within a hybrid diureasil matrix

    NASA Astrophysics Data System (ADS)

    Gonçalves, Luis F. F. F.; Silva, Carlos J. R.; Kanodarwala, Fehmida K.; Stride, John A.; Pereira, Mario R.; Gomes, Maria J. M.

    2014-09-01

    The incorporation of CdS nanoparticles (NPs), as prepared through colloidal methods using reverse micelles, within diureasil hybrid organic-inorganic sol-gel matrices was investigated. Several experimental conditions, namely the influence of capping agent 3-mercaptopropyltrimethoxysilane (MPTMS) or the use of tetraethoxysilane (TEOS), were studied in order to assure the preservation of the original optical properties of colloidal CdS NPs after the incorporation of the NPs within the solid diureasil hybrid matrix. The diureasil matrix is based on a siliceous network cross linked through urea bonds to poly(oxyethylene)/poly(oxypropylene) (PEO/PPO) chains. The influence of the Cd2+/S2- molar ratio of the NPs in the stability and dispersion of the NPs within the diureasil matrix was also investigated. The obtained CdS doped hybrid matrix was characterized by absorption, steady-state and time-resolved photoluminescence (PL) spectroscopy and by transmission electron microscopy (TEM). The stability of the CdS NPs within the hybrid matrix showed to be dependent on the Cd2+/S2- molar ratio used in the synthesis of the NPs. The use of MPTMS proved to be crucial in the preservation of the original optical properties of the colloidal CdS NPs after the incorporation of the NPs within the hybrid matrix. The effect of MPTMS was in turn influenced by the Cd2+/S2- molar ratio employed in the synthesis of the CdS NPs. The use of MPTMS was less effective when Cd2+/S2- molar ratio equal to 0.5 was used. In the absence of MPTMS or TEOS larger NPs size distribution and clustering of the CdS NPs were obtained after the transfer of the NPs into the hybrid matrix.

  3. Charge collection enhancement by incorporation of gold-silica core-shell nanoparticles into P3HT:PCBM/ZnO nanorod array hybrid solar cells.

    PubMed

    Wang, Ting-Chung; Su, Yen-Hsun; Hung, Yun-Kai; Yeh, Chen-Sheng; Huang, Li-Wen; Gomulya, Widianta; Lai, Lai-Hung; Loi, Maria A; Yang, Jih-Sheng; Wu, Jih-Jen

    2015-07-22

    In this work, gold-silica core-shell (Au@silica) nanoparticles (NPs) with various silica-shell thicknesses are incorporated into P3HT:PCBM/ZnO nanorod (NR) hybrid solar cells. Enhancement in the short-circuit current density and the efficiency of the hybrid solar cells is attained with the appropriate addition of Au@silica NPs regardless of the silica-shell thickness. Compared to the P3HT:PCBM/ZnO NR hybrid solar cell, a 63% enhancement in the efficiency is achieved by the P3HT:PCBM/Au@silica NP/ZnO NR hybrid solar cell. The finite difference time domain simulations indicate that the strength of the Fano resonance, i.e., the electric field of the quasi-static asymmetric quadrupole, on the surface of Au@silica NPs in the P3HT:PCBM/ZnO NR hybrid significantly decreases with increasing thickness of the silica shell. Raman characterization reveals that the degree of P3HT order increases when Au@silica NPs are incorporated into the P3HT:PCBM/ZnO NR hybrid. The charge separation at the interface between P3HT and PCBM as well as the electron transport in the active layer are retarded by the electric field of the Fano resonance. Nevertheless, the prolongation of the electron lifetime and the reduction of the electron transit time in the P3HT:PCBM/ZnO NR hybrid solar cells, which result in an enhancement of electron collection, are achieved by the addition of Au@silica NPs. This may be attributed to the improvement in the degree of P3HT order and connectivity of PCBM when Au@silica NPs are incorporated into the P3HT:PCBM active layer. PMID:26159896

  4. The anti-inflammatory effect of kaempferol on early atherosclerosis in high cholesterol fed rabbits

    PubMed Central

    2013-01-01

    Background Atherosclerosis has been widely accepted as an inflammatory disease of vascular, adhesion molecules play an important role in the early progression of it. The aim of the present study was to evaluate the effect of kaempferol on the inflammatory molecules such as E-selectin (E-sel), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesionmolecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1) in high cholesterol induced atherosclerosis rabbit models. Methods Thirty male New Zealand white (NZW) rabbits were randomly divided into five groups, control group, model group, fenofibrate (12mg/kg) group and kaempferol groups (150 mg/kg and 30 mg/kg). The rabbits were fed with a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, serum tumour-necrosis factor-alpha (TNF-?) and serum interleukin-1beta (IL-1?) were detected at the end of the sixth and tenth week. Malonaldehyde (MDA) level and superoxide dismutase (SOD) activity in serum were also determined. Lesion areas of the aorta were measured with morphometry analysis after ten weeks. Gene expression of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas was determined by RT-PCR (reverse transcription-polymerase chain reaction). Immunohistochemical staining was employed to measure protein expression of E-sel, ICAM-1, VCAM-1 and MCP-1. Results Model rabbits fed with ten weeks of high-cholesterol diet developed significant progression of atherosclerosis. Compared with the control, levels of blood lipids, TNF-?, IL-1? and MDA increased markedly in serum of model rabbits, while SOD levels decreased. Gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in atherosclerotic aortas increased remarkably in model group. However, comparing to the model rabbits, levels of TNF-?, IL-1? and MDA decreased significantly and serum SOD activity increased, gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas decreased significantly with the treatment of kaempferol. Conclusion Kaempferol shows anti-atherosclerotic effect by modulating the gene and protein expression of inflammatory molecules. PMID:23895132

  5. Kaempferol Induces DNA Damage and Inhibits DNA Repair Associated Protein Expressions in Human Promyelocytic Leukemia HL-60 Cells.

    PubMed

    Wu, Lung-Yuan; Lu, Hsu-Feng; Chou, Yu-Cheng; Shih, Yung-Luen; Bau, Da-Tian; Chen, Jaw-Chyun; Hsu, Shu-Chun; Chung, Jing-Gung

    2015-01-01

    Numerous evidences have shown that plant flavonoids (naturally occurring substances) have been reported to have chemopreventive activities and protect against experimental carcinogenesis. Kaempferol, one of the flavonoids, is widely distributed in fruits and vegetables, and may have cancer chemopreventive properties. However, the precise underlying mechanism regarding induced DNA damage and suppressed DNA repair system are poorly understood. In this study, we investigated whether kaempferol induced DNA damage and affected DNA repair associated protein expression in human leukemia HL-60 cells in vitro. Percentages of viable cells were measured via a flow cytometry assay. DNA damage was examined by Comet assay and DAPI staining. DNA fragmentation (ladder) was examined by DNA gel electrophoresis. The changes of protein levels associated with DNA repair were examined by Western blotting. Results showed that kaempferol dose-dependently decreased the viable cells. Comet assay indicated that kaempferol induced DNA damage (Comet tail) in a dose-dependent manner and DAPI staining also showed increased doses of kaempferol which led to increased DNA condensation, these effects are all of dose-dependent manners. Western blotting indicated that kaempferol-decreased protein expression associated with DNA repair system, such as phosphate-ataxia-telangiectasia mutated (p-ATM), phosphate-ataxia-telangiectasia and Rad3-related (p-ATR), 14-3-3 proteins sigma (14-3-3?), DNA-dependent serine/threonine protein kinase (DNA-PK), O(6)-methylguanine-DNA methyltransferase (MGMT), p53 and MDC1 protein expressions, but increased the protein expression of p-p53 and p-H2AX. Protein translocation was examined by confocal laser microscopy, and we found that kaempferol increased the levels of p-H2AX and p-p53 in HL-60 cells. Taken together, in the present study, we found that kaempferol induced DNA damage and suppressed DNA repair and inhibited DNA repair associated protein expression in HL-60 cells, which may be the factors for kaempferol induced cell death in vitro. PMID:25779644

  6. Small Molecule Kaempferol Promotes Insulin Sensitivity and Preserved Pancreatic ?-Cell Mass in Middle-Aged Obese Diabetic Mice

    PubMed Central

    Alkhalidy, Hana; Moore, William; Zhang, Yanling; Wang, Aihua; Ali, Mostafa; Suh, Kyung-Shin; Zhen, Wei; Cheng, Zhiyong; Jia, Zhenquan; Hulver, Matthew

    2015-01-01

    Insulin resistance and a progressive decline in functional ?-cell mass are hallmarks of developing type 2 diabetes (T2D). Thus, searching for natural, low-cost compounds to target these two defects could be a promising strategy to prevent the pathogenesis of T2D. Here, we show that dietary intake of flavonol kaempferol (0.05% in the diet) significantly ameliorated hyperglycemia, hyperinsulinemia, and circulating lipid profile, which were associated with the improved peripheral insulin sensitivity in middle-aged obese mice fed a high-fat (HF) diet. Kaempferol treatment reversed HF diet impaired glucose transport-4 (Glut4) and AMP-dependent protein kinase (AMPK) expression in both muscle and adipose tissues from obese mice. In vitro, kaempferol increased lipolysis and prevented high fatty acid-impaired glucose uptake, glycogen synthesis, AMPK activity, and Glut4 expression in skeletal muscle cells. Using another mouse model of T2D generated by HF diet feeding and low doses of streptozotocin injection, we found that kaempferol treatment significantly improved hyperglycemia, glucose tolerance, and blood insulin levels in obese diabetic mice, which are associated with the improved islet ?-cell mass. These results demonstrate that kaempferol may be a naturally occurring anti-diabetic agent by improving peripheral insulin sensitivity and protecting against pancreatic ?-cell dysfunction.

  7. Hybrid polymer:colloidal nanoparticle photovoltaic cells incorporating a solution-processed, multi-functioned ZnO nanocrystal layer

    NASA Astrophysics Data System (ADS)

    Yang, Jihua; Qian, Lei; Zhou, Renjia; Zheng, Ying; Tang, Aiwei; Holloway, Paul H.; Xue, Jiangeng

    2012-02-01

    We report significant improvement in both the power conversion efficiency and the environmental stability of solution-processed hybrid organic-inorganic solar cells by including a solution-processed ZnO nanocrystal layer between the photoactive layer and the cathode. For devices based on blends of poly(3-hexylthiophene) (P3HT) and mostly-spherical CdSe nanocrystals, incorporation of the ZnO layer leads to an up to 70% increase in the power conversion efficiency. Compared to only a few hours of shelf lifetime for unencapsulated devices with the metal cathode directly deposited on the hybrid active layer, devices with the ZnO layer can retain approximately 70% of the original efficiency when they are exposed to the laboratory ambient without encapsulation for more than two months. We attribute the function of this ZnO nanocrystal layer to a combination of optical, electronic, morphological, and chemical effects, including blocking leakage of photogenerated holes to the cathode, optimizing the optical intensity profile in the hybrid active layer, minimizing recombination or quenching of photogenerated excitons and charge carriers, significantly reducing the transport rate of oxygen and water molecules to the active layer and reducing degradation/oxidation of any low work function layer at the cathode interface.

  8. Fibrinolytic activity of kaempferol isolated from the fruits of Lagenaria siceraria (Molina) Standley.

    PubMed

    Rajput, M S; Mathur, Vineet; Agrawal, Purti; Chandrawanshi, H K; Pilaniya, Urmila

    2011-11-01

    This study was undertaken to isolate a flavonol, kaempferol, from the fruits of Lagenaria siceraria (bottle gourd) as a sole compound and to explore the fibrinolytic potential of the methanolic extract of the fruits of L. siceraria and the isolated compound using their in vitro activity. The fibrinolytic activity in terms of percentage of plasma clot liquefaction was determined by plasma clot lysis at 37°C in 24?h. The fibrinolytic activity of both substances was compared to the well-known thrombolytic agent streptokinase (30,000?IU). The percentage of fibrinolytic activity of the extract and isolated compound were found to be 54.72?±?0.7210 and 77.37?±?1.3010, respectively. Streptokinase was considered as the standard fibrinolytic enzyme for comparative purposes and had 91.46?±?0.7625% fibrinolytic activity. The conclusion drawn in our study after testing the hypothesis by experimental procedures is that in vitro fibrinolytic activity on plasma clots is an inherent property of kaempferol isolated from the fruits of L. siceraria, and its comparison with streptokinase is a new aspect for further study. PMID:21861768

  9. Kaempferol glycosides from Lobularia maritima and their potential role in plant interactions.

    PubMed

    Fiorentino, Antonio; Ricci, Andreina; D'Abrosca, Brigida; Golino, Annunziata; Izzo, Angelina; Pascarella, Maria Teresa; Piccolella, Simona; Esposito, Assunta

    2009-02-01

    Six kaempferol glycosides, four of them characterized for the first time, were isolated from the leaf extract of Lobularia maritima. The structural elucidation was performed by a combined approach using Electrospray-Ionization Triple-Quadrupole Mass-Spectrometric (ESI/TQ/MS) techniques, and 1D- and 2D-NMR experiments (1H, 13C, DEPT, DQ-COSY, TOCSY, ROESY, NOESY, HSQC, HMBC, and HSQC-TOCSY). The isolated kaempferol derivatives have different disaccharide substituents at C(3) and four of them have a rhamnose unit at C(7). To evaluate their potential allelopathic role within the herbaceous plant community, the compounds, as well as the aglycone obtained from enzymatic hydrolysis, have been tested in vitro on three coexisting plant species, Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum. The results obtained allow us to hypothesize that the type of the sugar modulates the biological response. The bioassay data, analyzed by a multivariate approach, and grouping the compounds on the basis of the number of sugar units and the nature of carbohydrates present in the disaccharide moiety, indicate a structure-activity relationship. PMID:19235162

  10. Synergistic effect of kaempferol glycosides purified from Laurus nobilis and fluoroquinolones on methicillin-resistant Staphylococcus aureus.

    PubMed

    Liu, Mei-Hua; Otsuka, Nao; Noyori, Kumiko; Shiota, Sumiko; Ogawa, Wakano; Kuroda, Teruo; Hatano, Tsutomu; Tsuchiya, Tomofusa

    2009-03-01

    In a previous study, we reported that two kaempferol glycosides isolated from Laurus nobilis L., kaempferol-3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-alpha-L-(2''-E-p-coumaroyl-4''-Z-p-coumaroyl)-rhamnoside (C3), showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci. Thereafter we found that these compounds greatly reduced the minimum inhibitory concentrations (MICs) of some fluoroquinolones in MRSA. In other words, C2 and C3 greatly potentiated anti-MRSA activity of fluoroquinolones. The effect of C2 and C3 with fluoroquinolones was found to be synergistic. The potentiation activity was observed with hydrophilic fluoroquinolones, such as norfloxacin and ciprofloxacin, but not with hydrophobic quinolones. We also found that norfloxacin reduced MICs of C2 and C3. The effect was synergistic. Possible mechanism of the synergistic effect was discussed. PMID:19252301

  11. Mechanisms of transformation of the antioxidant kaempferol into depsides. Gamma-radiolysis study in methanol and ethanol.

    PubMed

    Marfak, A; Trouillas, P; Allais, D P; Calliste, C A; Cook-Moreau, J; Duroux, J L

    2003-09-01

    In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol. PMID:12926994

  12. Inhibitory effects of kaempferol on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-9.

    PubMed

    Li, Chenglin; Zhao, Yuanwei; Yang, Dan; Yu, Yanyan; Guo, Hao; Zhao, Ziming; Zhang, Bei; Yin, Xiaoxing

    2015-02-01

    Matrix metalloproteinases (MMPs) have been regarded as major critical molecules assisting tumor cells during metastasis, for excessive ECM (ECM) degradation, and cancer cell invasion. In the present study, in vitro and in vivo assays were employed to examine the inhibitory effects of kaempferol, a natural polyphenol of flavonoid family, on tumor metastasis. Data showed that kaempferol could inhibit adhesion, migration, and invasion of MDA-MB-231 human breast carcinoma cells. Moreover, kaempferol led to the reduced activity and expression of MMP-2 and MMP-9, which were detected by gelatin zymography, real-time PCR, and western blot analysis, respectively. Further elucidation of the mechanism revealed that kaempferol treatment inhibited the activation of transcription factor activator protein-1 (AP-1) and MAPK signaling pathway. Moreover, kaempferol repressed phorbol-12-myristate-13-acetate (PMA)-induced MMP-9 expression and activity through suppressing the translocation of protein kinase C? (PKC?) and MAPK signaling pathway. Our results also indicated that kaempferol could block the lung metastasis of B16F10 murine melanoma cells as well as the expression of MMP-9 in vivo. Taken together, these results demonstrated that kaempferol could inhibit cancer cell invasion through blocking the PKC?/MAPK/AP-1 cascade and subsequent MMP-9 expression and its activity. Therefore, kaempferol might act as a therapeutic potential candidate for cancer metastasis. PMID:25453494

  13. Effects of the incorporation of silver and gold nanoparticles on the photoanodic properties of rose bengal sensitized TiO 2 film electrodes prepared by sol-gel method

    Microsoft Academic Search

    Gaoling Zhao; Hiromitsu Kozuka; Toshinobu Yoko

    1997-01-01

    Rose bengal-deposited TiO2 film electrodes bearing dispersed Ag or Au nanoparticles were prepared by the sol-gel method. The dye-induced visible region photoresponse of the electrodes decreased with increasing Ag content up to a mole ratio of Ag\\/TiO2 = 0.0207, while the UV photoresponse increased. On the other hand, the dye-induced visible region photoresponse decreased to a less extent by incorporation

  14. Nanoparticles

    NASA Astrophysics Data System (ADS)

    Keshavarz, Mohsen K.; Vasilevskiy, Dimitri; Masut, Remo A.; Turenne, Sylvain

    2014-06-01

    Nanostructured bulk materials are regarded as a means of enhancing the performance of thermoelectric (TE) materials and devices. Powder metallurgy has the distinct advantage over conventional synthesis that it can start directly from nanosized particles. However, further processing, for example extrusion, usually requires elevated temperatures, which lead to grain growth. We have found that introduction of semiconductor nanoparticles of molybdenum disulfide (MoS2), a well-known solid lubricant, suppresses grain growth in bismuth telluride-based alloys, thus improving the extrusion process. Scanning electron microscope images show that adding MoS2 particles at concentrations of 0.2, 0.4, and 0.8 wt% to p-type (Bi0.2Sb0.8)2Te3, under otherwise identical extrusion conditions, reduces average grain size by a factor of four. Scherer's formula applied to x-ray diffraction data indicates that average crystallite sizes (˜17 nm) of powders are not significantly different from those of alloys extruded with MoS2 (˜18 nm), which is in stark contrast with those for conventional alloy (Bi0.2Sb0.8)2Te3 extruded under the same conditions (˜80 nm). Harman measurements of TE properties reveal a decrease of the thermal conductivity accompanied by reduction of the room-temperature figure of merit ( ZT) from 0.9 to 0.7, because of a lower power factor. Above 370 K, however, the performance of alloys containing MoS2 surpasses that of (Bi0.2Sb0.8)2Te3, with reduction of the thermal conductivity which is more significant at temperatures above the cross point of the ZT values.

  15. Quantum dots (QDs) based fluorescence probe for the sensitive determination of kaempferol.

    PubMed

    Tan, Xuanping; Liu, Shaopu; Shen, Yizhong; He, Youqiu; Yang, Jidong

    2014-12-10

    In this work, using the quenching of fluorescence of thioglycollic acid (TGA)-capped CdTe quantum dots (QDs), a novel method for the determination of kaempferol (KAE) has been developed. Under optimum conditions, a linear calibration plot of the quenched fluorescence intensity at 552nm against the concentration of KAE was observed in the range of 4-44?gmL(-1) with a detection limit (3?/K) of 0.79?gmL(-1). In addition, the detailed reaction mechanism has also been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption and fluorescence (FL) spectroscopy. The method has been applied for the determination of KAE in pharmaceutical preparations with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation. PMID:24929317

  16. In vitro availability of kaempferol glycosides from cream formulations of methanolic extract of the leaves of Melilotus elegans

    Microsoft Academic Search

    Tsige Gebre-Mariam; Kaleab Asres; Melkamu Getie; Abebe Endale; Reinhard Neubert; Peter C. Schmidt

    2005-01-01

    In Ethiopian traditional medicine, Melilotus elegans Salzm. ex Ser. (Leguminosae) is used for the treatment of haemorrhoids and lacerated wounds. In view of its wide spread use and proven anti-inflammatory activity, 80% methanolic extract of the leaves was formulated into creams. HPLC\\/UV and MS studies revealed the presence of flavonoids, of which kaempferol was the major aglycone. Quantitative estimation of

  17. Effects of Long-Term Feeding of the Polyphenols Resveratrol and Kaempferol in Obese Mice

    PubMed Central

    Montero, Mayte; de la Fuente, Sergio; Fonteriz, Rosalba I.; Moreno, Alfredo; Alvarez, Javier

    2014-01-01

    The effect of the intake of antioxidant polyphenols such as resveratrol and others on survival and different parameters of life quality has been a matter of debate in the last years. We have studied here the effects of the polyphenols resveratrol and kaempferol added to the diet in a murine model undergoing long-term hypercaloric diet. Using 50 mice for each condition, we have monitored weight, survival, biochemical parameters such as blood glucose, insulin, cholesterol, triglycerides and aspartate aminotransferase, neuromuscular coordination measured with the rotarod test and morphological aspect of stained sections of liver and heart histological samples. Our data show that mice fed since they are 3-months-old with hypercaloric diet supplemented with any of these polyphenols reduced their weight by about 5–7% with respect to the controls fed only with hypercaloric diet. We also observed that mice fed with any of the polyphenols had reduced levels of glucose, insulin and cholesterol, and better marks in the rotarod test, but only after 1 year of treatment, that is, during senescence. No effect was observed in the rest of the parameters studied. Furthermore, although treatment with hypercaloric diets induced large changes in the pattern of gene expression in liver, we found no significant changes in gene expression induced by the presence of any of the polyphenols. Thus, our data indicate that addition of resveratrol or kaempferol to mice food produces an initial decrease in weight in mice subjected to hypercaloric diet, but beneficial effects in other parameters such as blood glucose, insulin and cholesterol, and neuromuscular coordination, only appear after prolonged treatments. PMID:25386805

  18. Antibacterial and antioxidant activities of four kaempferol methyl ethers isolated from Dodonaea viscosa Jacq. var . angustifolia leaf extracts

    Microsoft Academic Search

    L. S. Teffo; M. A. Aderogba; J. N. Eloff

    2010-01-01

    Fractionation of dichloromethane and acetone fractions obtained by serial extraction from the leaf powder of Dodonaea viscosa Jacq. var. angustifolia (Sapindaceae) resulted in the isolation of four kaempferol methyl ethers. The compounds were identified by spectral data (1H NMR, 13C NMR and MS) as: 3, 5, 7-trihydroxy-4'-methoxyflavone (1); 5, 7, 4'-trihydroxy-3, 6-dimethoxyflavone (2); 5, 7-dihydroxy-3, 6, 4'-trimethoxyflavone (santin) (3); and

  19. Study on the interactions of kaempferol and quercetin with intravenous immunoglobulin by fluorescence quenching, fourier transformation infrared spectroscopy and circular dichroism spectroscopy.

    PubMed

    Liu, Yong-Chun; Yang, Zheng-Yin; Du, Juan; Yao, Xiao-Jun; Lei, Rui-Xia; Zheng, Xu-Dong; Liu, Jian-Ning; Hu, Huai-Sheng; Li, Hong

    2008-04-01

    The interactions of kaempferol and quercetin with intravenous immunoglobulin (IVIG) were studied in vitro by spectroscopic methods including fluorescence spectra, Fourier transformation infrared (FT-IR) spectra and circular dichroism (CD) spectra. The binding parameters for the reactions calculated according to the Sips equation suggested that the bindings of IVIG to kaempferol and quercetin were characterized by two binding sites with the average affinity constants K(o) at 1.032 x 10(4) M(-1) and 1.849 x 10(4) M(-1), respectively. The binding of IVIG with quercetin is stronger than that of IVIG with kaempferol. They were of non-specific and weak drug-protein interactions. Docking was used to calculate the interaction modes between kaempferol and quercetin with IVIG. The secondary structural compositions of free IVIG and its kaempferol, quercetin complexes were calculated by the FT-IR difference spectra, self-deconvolution, second derivative resolution enhancement and the curve-fitting procedures of amide I band respectively, which are in good agreement with the analyses of CD spectra. The effect of 3'-OH substituent in quercetin is distinct between the interactions of IVIG with kaempferol and quercetin for the secondary structure of the protein. The observed spectral changes indicate a partial unfolding of the protein structure, but the typical beta structural conformation of IVIG is still retentive in the presence of both drugs in aqueous solution. The average binding distances between the chromophores of IVIG with kaempferol (4.30 nm) and quercetin (4.35 nm) were obtained on the basis of the theory of Förster energy transfer. IVIG can serve as transport protein (carrier) for kaempferol and quercetin. PMID:18379088

  20. Micelle-like nanoparticles of block copolymer poly(ethylene oxide)-block-poly(methacrylic acid) incorporating fluorescently substituted metallacarboranes designed as HIV protease inhibitor interaction probes.

    PubMed

    Uchman, Mariusz; Cígler, Petr; Grüner, Bohumír; Procházka, Karel; Matejícek, Pavel

    2010-08-01

    We prepared nanoparticles differing in morphology from double-hydrophilic block copolymer poly(ethylene oxide)-block-poly(methacrylic acid), PEO-PMA, and two types of fluorescein-[3-cobalt(III) bis(1,2-dicarbollide)] conjugates, GB176 and GB179, in alkaline buffer. GB176 molecule consists of fluorescein attached to the metallacarborane anion. In GB179 molecule, the fluorescein moiety connects two metallacarborane anions. The self-assembly is based on the unusual interaction of metallacarborane clusters with PEO blocks which form insoluble micellar cores. The GB176 containing nanoparticles are loose and irregular, while the GB179 ones are rigid and spherical. The structure of nanoparticles depends to some extent on a procedure of preparation. The micelles were studied by static and dynamic light scattering, fluorometry and atomic force microscopy. Since the metallacarborane conjugates act as potent inhibitors of HIV protease, the presented system is important from the point of view of drug delivery. PMID:20447643

  1. Optical fiber dissolved oxygen sensor based on Pt(II) complex and core-shell silica nanoparticles incorporated with sol–gel matrix

    Microsoft Academic Search

    Cheng-Shane Chu; Yu-Lung Lo

    2010-01-01

    This paper presents a highly sensitive dissolved oxygen sensor comprising an optical fiber coated at one end with core-shell silica nanoparticles and platinum(II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) embedded in an n-octyltriethoxysilane (Octyl-triEOS)\\/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of optical fiber dissolved oxygen sensor is quantified in terms of the ratio I0\\/I100, where I0 and I100 represent the detected fluorescence intensities

  2. Effects of solid dispersion and self-emulsifying formulations on the solubility, dissolution, permeability and pharmacokinetics of isorhamnetin, quercetin and kaempferol in total flavones of Hippophae rhamnoides L.

    PubMed

    Zhao, Guoying; Duan, Jingze; Xie, Yan; Lin, Guobei; Luo, Huilin; Li, Guowen; Yuan, Xiurong

    2013-07-01

    The aim of this study was to investigate the effects of solid dispersions (SD) and self-emulsifying (SE) formulations on the solubility and absorption properties of active components in total flavones of Hippophae rhamnoides L. (TFH). The solubility, dissolution rate, permeability and pharmacokinetics of isorhamnetin, quercetin and kaempferol in TFH SD/SE formulations and TFH were compared. The results showed that the solubility and dissolution rate of isorhamnetin, quercetin and kaempferol in SD/SE formulations were significantly enhanced compared to those in TFH, however, their intestinal permeability was comparable. The bioavailability of isorhamnetin, quercetin and kaempferol in rats remarkably increased after oral administration of TFH SD formulations compared to TFH, but there was no significant increase after oral administration of TFH SE formulations. The results of this study indicated the SD formulations on the improvement of pharmacokinetic properties of isorhamnetin, quercetin and kaempferol in TFH were much better than those of SE formulations. The improvement of pharmacokinetic properties of isorhamnetin, quercetin and kaempferol in TFH by SD formulations was probably ascribed to the enhancement of the solubility and dissolution of the three components, but was not relevant to the intestinal permeability. Therefore, as for herb extracts containing multiple components, especially for their major components with poor water solubility, solid dispersion formulations might have the better potential to enhance their bioavailability. PMID:22757776

  3. In-situ and ex-situ characterization of TiO2 and Au nanoparticle incorporated TiO2 thin films for optical gas sensing at extreme temperatures

    NASA Astrophysics Data System (ADS)

    Ohodnicki, Paul R.; Wang, Congjun; Natesakhawat, Sittichai; Baltrus, John P.; Brown, Thomas D.

    2012-03-01

    Sensor technologies that can operate under extreme conditions including high temperatures, high pressures, highly reducing and oxidizing environments, and corrosive gases are needed for process monitoring and control in advanced fossil energy applications. Sensor technologies based on optical waveguide-based techniques are highly attractive for passive, embedded, and remote sensing. A critical enabling technology for optical waveguide sensors is the development of advanced optical thin film coatings which have a desired set of optical properties that change in a rapid, selective, and sensitive manner to a particular quantity of interest. TiO2 and Au nanoparticle incorporated TiO2 nanocomposite thin films were prepared through sol-gel deposition techniques and their respective optical responses to a 4% H2/N2 mixture were investigated in the visible / near-IR range of 400-1000 nm. A tendency for Au nanoparticles to occupy special sites on the TiO2 microstructure, such as grain boundaries, twin boundaries, and triple points is rationalized in terms of basic surface energy arguments. The Au / TiO2 nanocomposite films showed a useful optical response due to a reversible, rapid, and repeatable shift in the localized surface plasma resonance peak of Au nanoparticles at a temperature of 650 °C and 850 °C. In contrast, high temperature exposure of TiO2 films to reducing gases at 850 °C resulted in the growth of abnormally large grains or "hillocks" that protruded from the sample surface and resulted in light scattering and an irreversible decrease in transmission at short wavelengths. The origin of the observed optical response of Au / TiO2 nanocomposite films is discussed in the context of work by prior investigators in the Au / yttria-stabilized Zirconia (YSZ) system and needs for future research in this area is highlighted.

  4. In vitro release and in vitro–in vivo correlation for silybin meglumine incorporated into hollow-type mesoporous silica nanoparticles

    PubMed Central

    Cao, Xia; Deng, Wen-Wen; Fu, Min; Wang, Liang; Tong, Shan-Shan; Wei, Ya-Wei; Xu, Ying; Su, Wei-Yan; Xu, Xi-ming; Yu, Jiang-Nan

    2012-01-01

    Background The purpose of this study was to develop a sustained drug-release model for water-soluble drugs using silica nanoparticles. Methods Hollow-type mesoporous silica nanoparticles (HMSNs) were prepared using Na2CO3 solution as the dissolution medium for the first time. The water-soluble compound, silybin meglumine, was used as the model drug. The Wagner–Nelson method was used to calculate the in vivo absorption fraction. Results The results of transmission electron microscopy and nitrogen adsorption revealed that the empty HMSNs had uniformly distributed particles of size 50–100 nm, a spherical appearance, a large specific surface area (385.89 ± 1.12 m2/g), and ultralow mean pore size (2.74 nm). The highly porous structure allowed a large drug-loading rate (58.91% ± 0.39%). In 0.08 M Na2CO3 solution, silybin meglumine-loaded HMSNs could achieve highly efficacious and long-term sustained release for 72 hours in vitro. The results of in vitro–in vivo correlation revealed that HMSNs in 0.08 M Na2CO3 solution had a correlation coefficient R2 value of 0.9931, while those of artificial gastric juice and artificial intestinal juice were only 0.9287 and 0.7689, respectively. Conclusion The findings of in vitro–in vivo correlation indicate that HMSNs together with Na2CO3 solution could achieve an excellent linear relationship between in vitro dissolution and in vivo absorption for 72 hours, leading to a promising model for sustained release of water-soluble drugs. PMID:22393284

  5. trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] incorporated in PLGA nanoparticles for the delivery of nitric oxide to B16-F10 cells: cytotoxicity and phototoxicity.

    PubMed

    Gomes, Anderson J; Espreafico, Enilza M; Tfouni, Elia

    2013-10-01

    The immobilization and characterization of trans-[Ru(NO)Cl(cyclam)](PF6)2 (cyclam=1,4,8,11-tetraazacyclotetradecane), and [Ru(NO)(Hedta)] (Hedta=ethylenediaminetetraacetic acid) entrapped in poly(d,l-lactic-co-glycolic) acid (PLGA) nanoparticles (NP) using the double emulsification process is described. Scanning electron microscopy and dynamic light scattering revealed that the particles are spherical in shape, have a size distribution between 220 and 840 nm of diameter, and have a tendency to aggregate confirmed by a zeta potential between -3.2 and +3.5 mV. Using this method the loading efficiency was 26% for trans-[Ru(NO)Cl(cyclam)](PF6)2 and 32% for [Ru(NO)(Hedta)]. The release of the complexes from the NPs shows that cyclam-NP and Hedta-NP exhibited a two-phase exponential association release pattern, which was characterized by an initial complex burst during the first 24 h, followed by a slower release phase complex profile, due to a few pores observed in surface of nanoparticles using atomic force microscopy. The in vitro cytotoxic activity of the nitrosyl complexes in solution and incorporated in PLGA nanoparticles on melanoma cancer cells (cell line B16-F10) was investigated. The lower cytotoxicity of trans-[RuCl(cyclam)(NO)]2+ (12.4±2.6%) and [Ru(NO)(Hedta)] (4.0±2.7%) in solution compared to that of trans-[Ru(NO)(NH3)4py]3+ (46.1±6.4%) is consistent with the rate constant release of NO of these complexes (k-NO=6.2×10(-4) s(-1), 2.0×10(-3) s(-1), and 6.0×10(-2) s(-1), respectively); the cytotoxicities are also inhibited in the presence of the NO scavenger carboxy-PTIO. The phototoxicity of these complexes is due to NO release, which lead to 53.8±6.2% of cell death in the presence of trans-[Ru(NO)Cl(cyclam)](PF6)2 and 22.3±5.1% in the presence of [Ru(NO)(Hedta)]. The PLGA nanoparticles loaded with trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] exerted in vitro a reduced activity against melanoma cells when compared to the activity of complex in solution (nonentrapped in nanoparticles). Blank PLGA nanoparticles did not exhibit cytotoxicity. In the presence of light and of ruthenium nitrosyl complexes or cyclam-NP and Hedta-NP, B16-F10 cells displayed a considerable damage of the surface with rupture of the plasma membrane. This behavior is an indicative of the efficiency of the DDS to deliver the NO from the entrapped complex when photoinduced. PMID:23865934

  6. Incorporation effect of nanosized perovskite LaFe?.?Co?.?O? on the electrochemical activity of Pt nanoparticles-multi walled carbon nanotube composite toward methanol oxidation

    SciTech Connect

    Noroozifar, Meissam, E-mail: mnoroozifar@chem.usb.ac.ir [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of); Khorasani-Motlagh, Mozhgan; Khaleghian-Moghadam, Roghayeh; Ekrami-Kakhki, Mehri-Saddat; Shahraki, Mohammad [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of)

    2013-05-01

    Nanosized perovskite LaFe?.?Co?.?O? (LFCO) is synthesized through conventional co-precipitation method and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPs-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation has been studied by cyclic voltammetry. Based on the electrochemical studies, all MWCNTs-PtNPs-nafion (or chitosan) and MWCNTs-PtNPs-LFCO-nafion (or chitosan) catalysts show a considerable activity for methanol oxidation. However, a synergistic effect is observed when LFCO is added to the catalyst by decreasing the poisoning rate of the Pt catalyst. - Graphical abstract: Nanosized perovskite LaFe?.?Co?.?O? is synthesized and characterized. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPS-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation is studied. Highlights: • Nanocrystalline LaFe?.?Co?.?O? (LFCO) is prepared by a new simple co-precipitation method. • Effect of LFCO to catalytic activity of PtNPS for methanol oxidation is studied. • A synergistic effect is observed when LFCO is added to the Pt catalyst. • Oxygen of LFCO could be considered as active oxygen to remove CO intermediates.

  7. Improved performance of CdS/CdSe quantum dots sensitized solar cell by incorporation of ZnO nanoparticles/reduced graphene oxide nanocomposite as photoelectrode

    NASA Astrophysics Data System (ADS)

    Ghoreishi, F. S.; Ahmadi, V.; Samadpour, M.

    2014-12-01

    Here we present novel quantum dot sensitized solar cells (QDSSC) based on ZnO nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite photoanodes for better light harvesting and energy conversion. Photoelectrodes are prepared by doctor blading ZnO NPs/GO nanocomposite paste on a fluorine doped tin oxide substrate which are then sintered at 450 °C to obtain ZnO NPs/RGO nanocomposites. The partial reduction of GO after thermal reduction, is studied by Fourier transform infrared and Raman spectroscopies. Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots are deposited on the films through successive ionic layer adsorption and reaction and chemical bath deposition methods, respectively. The unique properties of ZnO NPs/RGO photoanodes, lead to a significant enhancement in the photovoltaic properties of solar cells in comparison with bare ZnO photoanodes. Current-voltage characteristics of cells are studied and the best results are obtained from ZnO NPs-RGO/CdS/CdSe with photoelectric conversion efficiency of 2.20% which is almost two times higher than cells which are made by pure ZnO NPs as photoanode (1.28%). Electrochemical impedance measurements show that the enhancement can be attributed to the increase of electron transfer rate in the ZnO NPs/RGO nanocomposite photoanode which arises from the ultrahigh electron mobility in graphene (RGO) sheets.

  8. Simultaneous determination of catechin, rutin, quercetin kaempferol and isorhamnetin in the extract of sea buckthorn ( Hippophae rhamnoides L.) leaves by RP-HPLC with DAD

    Microsoft Academic Search

    Yuangang Zu; Chunying Li; Yujie Fu; Chunjian Zhao

    2006-01-01

    A rapid and specific reversed-phase high performance liquid chromatography (RP-HPLC) method with diode array detection (DAD) at room temperature was used and validated for the simultaneous determination of five flavonoids (catechin, CA; rutin, RU; quercetin, QU; kaempferol, KA; isorhamnetin, IS) in the extract of sea buckthorn (Hippophae rhamnoides L.) leaves. The sample pretreatment process involved ultrasonic extraction with 85% ethanol

  9. Solidphase extraction and gas chromatography–mass spectrometry determination of kaempferol and quercetin in human urine after consumption of Ginkgo biloba tablets

    Microsoft Academic Search

    D. G. Watson; E. J. Oliveira

    1999-01-01

    A method was developed for the quantification of the flavonoids quercetin and kaempferol in human urine using a solid-phase extraction procedure followed by gas chromatography–mass spectrometry. Deuterated internal standards of the analytes were spiked into the samples prior to extraction. The limit of detection of the method was ca. 10 pg on column and precision of the method for quantification

  10. Silver Nanoparticles in Dental Biomaterials

    PubMed Central

    Corrêa, Juliana Mattos; Mori, Matsuyoshi; Sanches, Heloísa Lajas; da Cruz, Adriana Dibo; Poiate, Isis Andréa Venturini Pola

    2015-01-01

    Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time. PMID:25667594

  11. 13C CP MAS NMR and GIAO-CHF/DFT calculations of flavonoids: Morin, kaempferol, tricin, genistein, formononetin and 3,7-dihydroxyflavone

    NASA Astrophysics Data System (ADS)

    Zieli?ska, Agnieszka; Paradowska, Katarzyna; Jakowski, Jacek; Wawer, Iwona

    2008-02-01

    13C CP MAS NMR spectra of the flavonoids: morin, kaempferol, 3,7-dihydroxyflavone, tricin and isoflavones: genistein and formononetin were recorded to characterize solid-state conformations. Intramolecular hydrogen bonds forming five-, six- and seven-membered rings are present in the two morin molecules in the crystals - their 13C resonances have been assigned with the aid of the calculated shielding constants. Linear relationships between the calculated shielding constants ?DFT (ppm) and chemical shifts ( ?CPMAS, ppm) were obtained for all studied compounds. Higher correlation coefficients suggest that the conformation with "clockwise" orientation of both OH groups is more probable in the solid 3,7-dihydroxyflavone, whereas in the solid formononetin the OH and OCH 3 substituents are directed "anticlockwise". The barrier to the rotation of phenyl ring B decreases in the order: morin (2'-OH, 3-OH) > kaempferol (3-OH) > tricin.

  12. Validated high-throughput HPLC method for the analysis of flavonol aglycones myricetin, quercetin, and kaempferol in Rhus coriaria L. using a monolithic column.

    PubMed

    Mehrdad, Morteza; Zebardast, Mahnoosh; Abedi, Ghazaleh; Koupaei, Mitra Nouri; Rasouli, Hoda; Talebi, Mohammad

    2009-01-01

    A rapid and simple reversed-phase high-performance liquid chromatographic method using a monolithic column was developed and validated for the separation and quantification of myricetin, quercetin, and kaempferol in Rhus coriaria L. The method employed the isocratic mobile phase acetonitrile-10 mM potassium dihydrogen orthophosphate buffer adjusted to pH 3.0 using orthophosphoric acid (38 + 62, v/v) at a flow rate of 4.0 mL/min; a Chromolith Performance RP-18e (100 x 4.6 mm) monolithic column kept at 40 degrees C; and UV detection at 370 nm. Although the elution order was identical and the selectivity was equivalent, the comparison between monolithic and particulate columns showed that the monolithic column could reduce the separation time to < 1 min without sacrificing column efficiency and selectivity. The method was validated according to International Conference on Harmonization guidelines. The validation characteristics included accuracy, precision, linearity, range, specificity, LOQ, and robustness. The calibration curves were linear (r > 0.999) over the concentration range of 0.88-88.3 micro/mL for myricetin, 0.95-95 microg/mL for quercetin, and 1.43-143.3 microg/mL for kaempferol. The recoveries for all three compounds were above 89%. Myricetin was found to be the major flavonol in the examined plant extracts, followed by minor quantities of quercetin and kaempferol. PMID:19714969

  13. Kaempferol blocks oxidative stress in cerebellar granule cells and reveals a key role for reactive oxygen species production at the plasma membrane in the commitment to apoptosis.

    PubMed

    Samhan-Arias, Alejandro Khalil; Martín-Romero, Francisco Javier; Gutiérrez-Merino, Carlos

    2004-07-01

    Micromolar concentrations of the flavonoid kaempferol were found to efficiently block cerebellar granule cell (CGC) death through low K+-induced apoptosis, as demonstrated by prevention of the activation of caspase-3, internucleosomal DNA fragmentation, and chromatin condensation, without a significant rise in intracellular free Ca2+ concentration. Half of the maximum protection against CGC apoptosis was attained with 8 +/- 2 microM kaempferol. Reactive oxygen species (ROS) were monitored with 2',7'-dichlorodihydrofluorescein diacetate. Quantitative analysis of intracellularly and extracellularly oriented ROS production up to 3 h from the onset of low K+-induced CGC apoptosis was carried out with acquired digital fluorescence microscopy images of CGC in culture plates using a CCD camera, and also with fluorescence measurements of resuspended CGCs. In both cases, nearly 90% of ROS production by CGCs during the early stages (up to 3 h) after induction of low-K+ apoptosis occurs at the plasma membrane. Kaempferol, at concentrations that blocked CGC apoptosis, has been found to be a particularly potent blocker of extracellularly oriented ROS production by CGCs, and to inhibit the ascorbate-dependent NADH oxidase and superoxide anion production activities of the neuronal plasma membrane redox chain. PMID:15183194

  14. Effect of Ginkgo biloba extract on procarcinogen-bioactivating human CYP1 enzymes: Identification of isorhamnetin, kaempferol, and quercetin as potent inhibitors of CYP1B1

    SciTech Connect

    Chang, Thomas K.H. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3 (Canada)]. E-mail: tchang@interchange.ubc.ca; Chen Jie [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3 (Canada); Yeung, Eugene Y.H. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3 (Canada)

    2006-05-15

    In the present study, we investigated the effect of Ginkgo biloba extracts and some of its individual constituents on the catalytic activity of human cytochrome P450 enzymes CYP1B1, CYP1A1, and CYP1A2. G. biloba extract of known abundance of terpene trilactones and flavonol glycosides inhibited 7-ethoxyresorufin O-dealkylation catalyzed by human recombinant CYP1B1, CYP1A1, and CYP1A2, and human liver microsomes, with apparent K {sub i} values of 2 {+-} 0.3, 5 {+-} 0.5, 16 {+-} 1.4, and 39 {+-} 1.2 {mu}g/ml (mean {+-} SE), respectively. In each case, the mode of inhibition was of the mixed type. Bilobalide, ginkgolides A, B, C, and J, quercetin 3-O-rutinoside, kaempferol 3-O-rutinoside, and isorhamentin 3-O-rutinoside were not responsible for the inhibition of CYP1 enzymes by G. biloba extract, as determined by experiments with these individual chemicals at the levels present in the extract. In contrast, the aglycones of quercetin, kaempferol, and isorhamentin inhibited CYP1B1, CYP1A1, and CYP1A2. Among the three flavonol aglycones, isorhamentin was the most potent in inhibiting CYP1B1 (apparent K {sub i} = 3 {+-} 0.1 nM), whereas quercetin was the least potent in inhibiting CYP1A2 (apparent K {sub i} 418 {+-} 50 nM). The mode of inhibition was competitive, noncompetitive, or mixed, depending on the enzyme and the flavonol. G. biloba extract also reduced benzo[a]pyrene hydroxylation, and the effect was greater with CYP1B1 than with CYP1A1 as the catalyst. Overall, our novel findings indicate that G. biloba extract and the flavonol aglycones isorhamnetin, kaempferol, and quercetin preferentially inhibit the in vitro catalytic activity of human CYP1B1.

  15. Composite nanoparticles for gene delivery.

    PubMed

    Wang, Yuhua; Huang, Leaf

    2014-01-01

    Nanoparticle-mediated gene and siRNA delivery has been an appealing area to gene therapists when they attempt to treat the diseases by manipulating the genetic information in the target cells. However, the advances in materials science could not keep up with the demand for multifunctional nanomaterials to achieve desired delivery efficiency. Researchers have thus taken an alternative approach to incorporate various materials into single composite nanoparticle using different fabrication methods. This approach allows nanoparticles to possess defined nanostructures as well as multiple functionalities to overcome the critical extracellular and intracellular barriers to successful gene delivery. This chapter will highlight the advances of fabrication methods that have the most potential to translate nanoparticles from bench to bedside. Furthermore, a major class of composite nanoparticle-lipid-based composite nanoparticles will be classified based on the components and reviewed in details. PMID:25409605

  16. Kaempferol 3-O-rhamnoside-7-O-rhamnoside is an endogenous flavonol inhibitor of polar auxin transport in Arabidopsis shoots.

    PubMed

    Yin, Ruohe; Han, Kerstin; Heller, Werner; Albert, Andreas; Dobrev, Petre I; Zažímalová, Eva; Schäffner, Anton R

    2014-01-01

    Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. The differential flavonol patterns established were analyzed by high-performance liquid chromatography (HPLC) and related to altered plant stature. PAT was monitored in stem segments using a radioactive [(3) H]-indole-3-acetic acid tracer. The flavonoid 3-O-glucosyltransferase mutant ugt78d2 exhibited a dwarf stature in addition to its altered flavonol glycoside pattern. This was accompanied by reduced PAT in ugt78d2 shoots. The ugt78d2-dependent growth defects were flavonoid dependent, as they were rescued by genetic blocking of flavonoid biosynthesis. Phenotypic and metabolic analyses of a series of mutants defective at various steps of flavonoid formation narrowed down the potentially active moiety to kaempferol 3-O-rhamnoside-7-O-rhamnoside. Moreover, the level of this compound was negatively correlated with basipetal auxin transport. These results indicate that kaempferol 3-O-rhamnoside-7-O-rhamnoside acts as an endogenous PAT inhibitor in Arabidopsis shoots. PMID:24251900

  17. The anti-obesity and anti-diabetic effects of kaempferol glycosides from unripe soybean leaves in high-fat-diet mice.

    PubMed

    Zang, Yanqing; Zhang, Liping; Igarashi, Kiharu; Yu, Changqing

    2015-03-11

    The present study investigated the anti-obesity and anti-diabetic effects of kaempferol glycoside (KG) fractions which were composed of four kaempferol glycosides and purified from unripe Jindai-soybean (Edamame) leaves in C57BL/6J mice. High fat-fed mice treated with 0.15% dietary KG for 92 days had reduced body weight, adipose tissue and TG levels compared to the high fat-fed control group. KG-treatment also decreased fasting blood glucose, serum HbA1c (hemoglobin A1c) levels and improved insulin resistance. Gene expression analysis of the liver showed that KG decreased peroxisome proliferator-activated receptor (PPAR-?) and sterol regulatory element-binding protein (SREBP-1c) expression. These results suggest that KG reduced the accumulation of adipose tissue, improving hyperlipidemia as well as diabetes in obese mice by increasing lipid metabolism through the downregulation of PPAR-? and SREBP-1c. Thus, KG may have an anti-obesity and anti-diabetic potential. PMID:25599885

  18. Carbon Materials Metal/Metal Oxide Nanoparticle Composite and Battery Anode Composed of the Same

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2006-01-01

    A method of forming a composite material for use as an anode for a lithium-ion battery is disclosed. The steps include selecting a carbon material as a constituent part of the composite, chemically treating the selected carbon material to receive nanoparticles, incorporating nanoparticles into the chemically treated carbon material and removing surface nanoparticles from an outside surface of the carbon material with incorporated nanoparticles. A material making up the nanoparticles alloys with lithium.

  19. Nanoparticles for Imaging: Top or Flop?

    PubMed Central

    Kiessling, Fabian; Mertens, Marianne E.; Grimm, Jan; Lammers, Twan

    2014-01-01

    Nanoparticles are frequently suggested as diagnostic agents. However, except for iron oxide nanoparticles, diagnostic nanoparticles have been barely incorporated into clinical use so far. This is predominantly due to difficulties in achieving acceptable pharmacokinetic properties and reproducible particle uniformity as well as to concerns about toxicity, biodegradation, and elimination. Reasonable indications for the clinical utilization of nanoparticles should consider their biologic behavior. For example, many nanoparticles are taken up by macrophages and accumulate in macrophage-rich tissues. Thus, they can be used to provide contrast in liver, spleen, lymph nodes, and inflammatory lesions (eg, atherosclerotic plaques). Furthermore, cells can be efficiently labeled with nanoparticles, enabling the localization of implanted (stem) cells and tissue-engineered grafts as well as in vivo migration studies of cells. The potential of using nanoparticles for molecular imaging is compromised because their pharmacokinetic properties are difficult to control. Ideal targets for nanoparticles are localized on the endothelial luminal surface, whereas targeted nanoparticle delivery to extravascular structures is often limited and difficult to separate from an underlying enhanced permeability and retention (EPR) effect. The majority of clinically used nanoparticle-based drug delivery systems are based on the EPR effect, and, for their more personalized use, imaging markers can be incorporated to monitor biodistribution, target site accumulation, drug release, and treatment efficacy. In conclusion, although nanoparticles are not always the right choice for molecular imaging (because smaller or larger molecules might provide more specific information), there are other diagnostic and theranostic applications for which nanoparticles hold substantial clinical potential. PMID:25247562

  20. Metal-doped semiconductor nanoparticles and methods of synthesis thereof

    NASA Technical Reports Server (NTRS)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Poudel, Bed (Inventor); Kumar, Shankar (Inventor); Wang, Wenzhong (Inventor); Dresselhaus, Mildred (Inventor)

    2009-01-01

    The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

  1. Transparent nanocomposites based on refractive index matched nanoparticles

    E-print Network

    Candea, George

    Transparent nanocomposites based on refractive index matched nanoparticles Katja Fröhlich1,2, Eleni Figure 1: Left: Pure polymer. Right: With nanoparticles reinforced polymer. Methods and Results nsolvent-resistance by incorporation of nanoparticles as fillers. · Transparency achieved by match of refractive indices n of filler p

  2. Metal-doped semiconductor nanoparticles and methods of synthesis thereof

    DOEpatents

    Ren, Zhifeng (Newton, MA); Chen, Gang (Carlisle, MA); Poudel, Bed (West Newton, MA); Kumar, Shankar (Newton, MA); Wang, Wenzhong (Beijing, CN); Dresselhaus, Mildred (Arlington, MA)

    2009-09-08

    The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

  3. Fabrication of latex rubber reinforced with micellar nanoparticle as an interface modifier

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reinforced latex rubbers were fabricated by incorporating small amount of nanoparticles as interface modifier. The rubbers were fabricated in a compression mold at 130°C. The incorporated nanoparticles were prepared from wheat protein (gliadin) and ethyl cyanoacrylate (ECA). These nanoparticles were...

  4. Inhibitory effects of kaempferol-3-O-rhamnoside on ovalbumin-induced lung inflammation in a mouse model of allergic asthma.

    PubMed

    Chung, Mi Ja; Pandey, Ramesh Prasad; Choi, Ji Won; Sohng, Jae Kyung; Choi, Doo Jin; Park, Yong Il

    2015-04-01

    The modification of natural flavonoid by glycosylation alters their physicochemical and pharmacokinetic properties, such as increased water solubility and stability, reduced toxicity, and sometimes enhanced or even new pharmacological activities. Kaempferol (KF), a plant flavonoid, and its glycosylated derivative, kaempferol-3-O-rhamnoside (K-3-rh), were evaluated and compared for their anti-inflammatory, anti-oxidant, and anti-asthmatic effects in an asthma model mouse. The results showed that K-3-rh fully maintained its anti-inflammatory and anti-asthmatic effects compared with KF in an asthma model mouse. Both KF and K-3-rh significantly reduced the elevated inflammatory cell numbers in the bronchoalveolar lavage fluid (BALF). KF and K-3-rh also significantly inhibited the increase in Th2 cytokines (IL-4, IL-5, and IL-13) and TNF-? protein levels through inhibition of the phosphorylation Akt and effectively suppressed eosinophilia in a mouse model of allergic asthma. The total immunoglobulin (Ig) E levels in the serum and BALF were also blocked by KF and K-3-rh to similar extents. K-3-rh exerts similar or even slightly higher inhibitory effects on Th2 cytokines and IgE production compared with KF, whereas K-3-rh was less effective at DPPH radical scavenging and the inhibition of ROS generation in inflammatory cells compared with KF. These results suggested that the K-3-rh, as well as KF, may also be a promising candidate for the development of health beneficial foods or therapeutic agents that can prevent or treat allergic asthma. PMID:25698556

  5. Antiplasmodial properties of kaempferol-3-O-rhamnoside isolated from the leaves of Schima wallichii against chloroquine-resistant Plasmodium falciparum

    PubMed Central

    BARLIANA, MELISA I.; SURADJI, EKA W.; ABDULAH, RIZKY; DIANTINI, AJENG; HATABU, TOSHIMITSU; NAKAJIMA-SHIMADA, JUNKO; SUBARNAS, ANAS; KOYAMA, HIROSHI

    2014-01-01

    Previous intervention studies have shown that the most effective agents used in the treatment of malaria were isolated from natural sources. Plants consumed by non-human primates serve as potential drug sources for human disease management due to the similarities in anatomy, physiology and disease characteristics. The present study investigated the antiplasmodial properties of the primate-consumed plant, Schima wallichii (S. wallichii) Korth. (family Theaceae), which has already been reported to have several biological activities. The ethanol extract of S. wallichii was fractionated based on polarity using n-hexane, ethyl acetate and water. The antiplasmodial activity was tested in vitro against chloroquine-resistant Plasmodium falciparum (P. falciparum) at 100 ?g/ml for 72 h. The major compound of the most active ethyl acetate fraction was subsequently isolated using column chromatography and identified by nuclear magnetic resonance. The characterized compound was also tested against chloroquine-resistant P. falciparum in culture to evaluate its antiplasmodial activity. The ethanol extract of S. wallichii at 100 ?g/ml exhibited a significant parasite shrinkage after 24 h of treatment. The ethyl acetate fraction at 100 ?g/ml was the most active fraction against chloroquine-resistant P. falciparum. Based on the structural characterization, the major compound isolated from the ethyl acetate fraction was kaempferol-3-O-rhamnoside, which showed promising antiplasmodial activity against chloroquine-resistant P. falciparum with an IC50 of 106 ?M after 24 h of treatment. The present study has provided a basis for the further investigation of kaempferol-3-O-rhamnoside as an active compound for potential antimalarial therapeutics. PMID:24944812

  6. Neuroprotective Effect of Kaempferol Glycosides against Brain Injury and Neuroinflammation by Inhibiting the Activation of NF-?B and STAT3 in Transient Focal Stroke

    PubMed Central

    Wang, Liang-Fen; Kuang, Xi; Liu, Ke; Zhang, Hao; Du, Jun-Rong

    2013-01-01

    Background Ischemic brain injury is associated with neuroinflammatory response, which essentially involves glial activation and neutrophil infiltration. Transcription factors nuclear factor-?B (NF-?B) and signal transducer and activator of transcription 3 (STAT3) contribute to ischemic neuroinflammatory processes and secondary brain injury by releasing proinflammatory mediators. Kaempferol-3-O-rutinoside (KRS) and kaempferol-3-O- glucoside (KGS) are primary flavonoids found in Carthamus tinctorius L. Recent studies demonstrated that KRS protected against ischemic brain injury. However, little is known about the underlying mechanisms. Flavonoids have been reported to have antiinflammatory properties. Herein, we explored the effects of KRS and KGS in a transient focal stroke model. Methodology/Principal Findings Rats were subjected to middle cerebral artery occlusion for 2 hours followed by 22 h reperfusion. An equimolar dose of KRS or KGS was administered i.v. at the beginning of reperfusion. The results showed that KRS or KGS significantly attenuated the neurological deficits, brain infarct volume, and neuron and axon injury, reflected by the upregulation of neuronal nuclear antigen-positive neurons and downregulation of amyloid precursor protein immunoreactivity in the ipsilateral ischemic hemisphere. Moreover, KRS and KGS inhibited the expression of OX-42, glial fibrillary acidic protein, phosphorylated STAT3 and NF-?B p65, and the nuclear content of NF-?B p65. Subsequently, these flavonoids inhibited the expression of tumor necrosis factor ?, interleukin 1?, intercellular adhesion molecule 1, matrix metallopeptidase 9, inducible nitric oxide synthase, and myeloperoxidase. Conclusion/Significance Our findings suggest that postischemic treatment with KRS or KGS prevents ischemic brain injury and neuroinflammation by inhibition of STAT3 and NF-?B activation and has the therapeutic potential for the neuroinflammation-related diseases, such as ischemic stroke. PMID:23437066

  7. Structural investigations on lipid nanoparticles containing high amounts of lecithin

    Microsoft Academic Search

    Martin Alexander Schubert; Meike Harms; Christel Charlotte Müller-Goymann

    2006-01-01

    Solid lipid nanoparticles (SLN), an alternative colloidal drug delivery system to polymer nanoparticles, emulsions and liposomes, possess inherent low incorporation rates resulting from the crystalline structure of the solid lipid. To increase the drug loading capacity of SLN, matrix modification by incorporation of the amphiphilic lipid lecithin within the lipid matrices has been proposed as a promising alternative. The objective

  8. Effects of Parsley (Petroselinum crispum) and its Flavonol Constituents, Kaempferol and Quercetin, on Serum Uric Acid Levels, Biomarkers of Oxidative Stress and Liver Xanthine Oxidoreductase Aactivity inOxonate-Induced Hyperuricemic Rats

    PubMed Central

    Haidari, Fatemeh; Keshavarz, Seid Ali; Mohammad Shahi, Majid; Mahboob, Soltan-Ali; Rashidi, Mohammad-Reza

    2011-01-01

    Increased serum uric acid is known to be a major risk related to the development of several oxidative stress diseases. The aim of this study was to investigate the effect of parsley, quercetin and kaempferol on serum uric acid levels, liver xanthine oxidoreductase activity and two non-invasive biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) in normal and oxonate-induced hyperuricemic rats. A total of 60 male Wistar rats were randomly divided into ten equal groups; including 5 normal groups (vehicle, parsley, quercetin, kaempferol and allopurinol) and 5 hyperuricemic groups (vehicle, parsley, quercetin, kaempferol and allopurinol). Parsley (5 g/Kg), quercetin (5 mg/Kg), kaempferol (5 mg/Kg) and allopurinol (5 mg/Kg) were administrated to the corresponding groups by oral gavage once a day for 2 weeks. The results showed that parsley and its flavonol did not cause any significant reduction in the serum uric acid levels in normal rats, but significantly reduced the serum uric acid levels of hyperuricemic rats in a time-dependent manner. All treatments significantly inhibited liver xanthine oxidoreductase activity. Parsley, kaempferol and quercetin treatment led also to a significant increase in total antioxidant capacity and decrease in malondialdehyde concentration in hyperuricemic rats. Although the hypouricemic effect of allopurinol was much higher than that of parsley and its flavonol constituents, it could not significantly change oxidative stress biomarkers. These features of parsley and its flavonols make them as a possible alternative for allopurinol, or at least in combination therapy to minimize the side effects of allopurinol to treat hyperuricemia and oxidative stress diseases. PMID:24250417

  9. Nanoparticles for drug delivery to the lungs.

    PubMed

    Sung, Jean C; Pulliam, Brian L; Edwards, David A

    2007-12-01

    The lungs are an attractive route for non-invasive drug delivery with advantages for both systemic and local applications. Incorporating therapeutics with polymeric nanoparticles offers additional degrees of manipulation for delivery systems, providing sustained release and the ability to target specific cells and organs. However, nanoparticle delivery to the lungs has many challenges including formulation instability due to particle-particle interactions and poor delivery efficiency due to exhalation of low-inertia nanoparticles. Thus, novel methods formulating nanoparticles into the form of micron-scale dry powders have been developed. These carrier particles exhibit improved handling and delivery, while releasing nanoparticles upon deposition in the lungs. This review covers the development of nanoparticle formulations for pulmonary delivery as both individual nanoparticles and encapsulated within carrier particles. PMID:17997181

  10. Brain uptake of thiamine-coated nanoparticles.

    PubMed

    Lockman, Paul R; Oyewumi, Moses O; Koziara, Joanna M; Roder, Karen E; Mumper, Russell J; Allen, David D

    2003-12-12

    Recently, a novel nanoparticle (NP) comprised of emulsifying wax and Brij 78 was shown to have significant brain uptake using the in-situ rat brain perfusion technique. To further these studies and to specifically target brain, we have incorporated thiamine as a surface ligand on the nanoparticles. Solid nanoparticles were prepared from oil-in-water microemulsion precursors. Nanoparticles were radiolabeled and a thiamine ligand (thiamine linked to distearoylphosphatidylethanolamine via a polyethylene glycol spacer) was coated on the surface of the nanoparticles. Initial experiments focused on assessing uptake of [3H]nanoparticles with and without thiamine surface ligands. Biodistribution nanoparticle studies were also carried out in BALB/c mice. The results showed: (1) the effectiveness of using microemulsions as precursors to engineer nanoparticles, (2) kinetic modeling for brain uptake of nanoparticles with and without the thiamine surface ligands, and (3) initial data suggesting mechanisms for nanoparticle brain entry. Comparison of NP brain uptake demonstrated that the thiamine-coated nanoparticle associated with the blood-brain barrier (BBB) thiamine transporter and had an increased K(in) between 45 and 120 s (thiamine coated NP 9.8 +/- 1.1 x 10(-3) ml/s/g versus uncoated NPs; 7.0 +/- 0.3 x 10(-3) ml/s/g). It was concluded that the thiamine ligand facilitated binding and/or association with blood-brain barrier thiamine transporters, which may be a viable mechanism for nanoparticle mediated brain drug delivery. PMID:14644577

  11. Improved barrier and mechanical properties of novel hydroxypropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitosan/tripolyphosphate nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films. FT-IR and transmission electron microscopy (TEM) analyses of the nanoparticles, mechanical properties, water vapor permeability, thermal stability, scanning electron microscopy (SEM...

  12. Development of molecular indicators to track the effects of nanoparticle toxicity in Arabidopsis thaliana

    EPA Science Inventory

    The emergence of nanotechnology and incorporation of nanoparticles in consumer products necessitates risk assessment from an environmental and health safety standpoint. To date, very few studies have examined nanoparticle effects on terrestrial species, especially plants. Pre...

  13. Fabrication, characterization and microwave properties of polyurethane nanocomposites reinforced with iron oxide and barium titanate nanoparticles

    Microsoft Academic Search

    Z. Guo; S.-E. Lee; H. Kim; H. T. Hahn; A. B. Karki; D. P. Young

    2009-01-01

    Polyurethane (PU) nanocomposites reinforced with magnetic iron oxide nanoparticles and\\/or dielectric barium titanate nanoparticles fabricated by the surface-initiated-polymerization approach were investigated. The polymer matrix incorporated with different nanoparticles shows different presenting status surrounding the nanoparticles, i.e., chemical bonding, physical entanglement and bulk polymer chain. The nanoparticles have a different effect on the thermal stability of the polymer nanocomposites. By embedding

  14. Application of Magnetic Nanoparticles to Gene Delivery

    PubMed Central

    Kami, Daisuke; Takeda, Shogo; Itakura, Yoko; Gojo, Satoshi; Watanabe, Masatoshi; Toyoda, Masashi

    2011-01-01

    Nanoparticle technology is being incorporated into many areas of molecular science and biomedicine. Because nanoparticles are small enough to enter almost all areas of the body, including the circulatory system and cells, they have been and continue to be exploited for basic biomedical research as well as clinical diagnostic and therapeutic applications. For example, nanoparticles hold great promise for enabling gene therapy to reach its full potential by facilitating targeted delivery of DNA into tissues and cells. Substantial progress has been made in binding DNA to nanoparticles and controlling the behavior of these complexes. In this article, we review research on binding DNAs to nanoparticles as well as our latest study on non-viral gene delivery using polyethylenimine-coated magnetic nanoparticles. PMID:21747701

  15. Investigations of nano-particle toxicity and uptake of Cerium oxide and Titanium dioxide in Arabidopsis thaliana (L.)

    EPA Science Inventory

    The emergence of nanotechnology and incorporation of nanoparticles in consumer products necessitates risk assessment from an environmental and health safety standpoint. To date, very few studies have examined nanoparticle effects on terrestrial species, especially plants. In ...

  16. DNA templated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kinsella, Joseph M.

    Recent discoveries in nanoscience are predicted to potentially revolutionize future technologies in an extensive number of fields. These developments are contingent upon discovering new and often unconventional methods to synthesize and control nanoscale components. Nature provides several examples of working nanotechnology such as the use of programmed self assembly to build and deconstruct complex molecular systems. We have adopted a method to control the one dimensional assembly of magnetic nanoparticles using DNA as a scaffold molecule. With this method we have demonstrated the ability to organize 5 nm particles into chains that stretch up to ˜20 mum in length. One advantage of using DNA compared is the ability of the molecule to interact with other biomolecules. After assembling particles onto DNA we have been able to cleave the molecule into smaller fragments using restriction enzymes. Using ligase enzymes we have re-connected these fragments, coated with either gold or iron oxide, to form long one-dimensional arrangements of the two different types of nanoparticles on a single molecular guide. We have also created a sensitive magnetic field sensor by incorporating magnetic nanoparticle coated DNA strands with microfabricated electrodes. The IV characteristics of the aligned nanoparticles are dependant on the magnitude of an externally applied magnetic field. This transport phenomenon known as tunneling magnetoresistance (TMR) shows room temperature resistance of our devices over 80% for cobalt ferrite coated DNA when a field of 20 kOe is applied. In comparison, studies using two dimensional nanoparticle films of irox oxides xii only exhibit a 35% MR effect. Confinement into one dimension using the DNA guide produces a TMR mechanism which produces significant increases in magnetoresistance. This property can be utilized for applications in magnetic field sensing, data storage, and logic elements.

  17. Nanoparticle-sulphur "inverse vulcanisation" polymer composites.

    PubMed

    Bear, Joseph C; Peveler, William J; McNaughter, Paul D; Parkin, Ivan P; O'Brien, Paul; Dunnill, Charles W

    2015-06-16

    Composites of sulphur polymers with nanoparticles such as PbS, with tunable optical properties are reported. A hydrothermal route incorporating pre-formed nanoparticles was used, and their physical and chemical properties evaluated by transmission and scanning electron microscopy, thermogravimetric and elemental analyses. These polymers are easily synthesised from an industrial waste material, elemental sulphur, can be cast into virtually any form and as such represent a new class of materials designed for a responsible energy future. PMID:26028319

  18. Synthesis, Stability, and Cellular Internalization of Gold Nanoparticles Containing Mixed Peptide?Poly(ethylene glycol) Monolayers

    Microsoft Academic Search

    Yanli Liu; Mathew K. Shipton; Joseph Ryan; Eric D. Kaufman; Stefan Franzen; Daniel L. Feldheim

    2007-01-01

    Gold nanoparticles have shown great promise as thera- peutics, therapeutic delivery vectors, and intracellular imaging agents. For many biomedical applications, selec- tive cell and nuclear targeting are desirable, and these remain a significant practical challenge in the use of nanoparticles in vivo. This challenge is being addressed by the incorporation of cell-targeting peptides or antibod- ies onto the nanoparticle surface,

  19. Properties of Novel Hydroxypropyl Methylcellulose Films Containing Chitosan Nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, chitosan nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films under different conditions. Mechanical properties, water vapor and oxygen permeability, water solubility and scanning and transmission electron microscopy (SEM and TEM) results were ana...

  20. Metal-nanoparticle single-electron transistors fabricated using electromigration

    Microsoft Academic Search

    K. I. Bolotin; F. Kuemmeth; A. N. Pasupathy; D. C. Ralph

    2004-01-01

    We have fabricated single-electron transistors from individual metal nanoparticles using a geometry that provides improved coupling between the particle and the gate electrode. This is accomplished by incorporating a nanoparticle into a gap created between two electrodes using electromigration, all on top of an oxidized aluminum gate. We achieve sufficient gate coupling to access more than ten charge states of

  1. Nanoparticle-Mediated Gene Delivery

    NASA Astrophysics Data System (ADS)

    Jin, Sha; Leach, John C.; Ye, Kaiming

    Nonviral gene delivery has been gaining considerable attention recently. Although the efficacy of DNA transfection, which is a major concern, is low in nonviral vector-mediated gene transfer compared with viral ones, nonviral vectors are relatively easy to prepare, less immunogenic and oncogenic, and have no potential of virus recombination and no limitation on the size of a transferred gene. The ability to incorporate genetic materials such as plasmid DNA, RNA, and siRNA into functionalized nanoparticles with little toxicity demonstrates a new era in pharmacotherapy for delivering genes selectively to tissues and cells. In this chapter, we highlight the basic concepts and applications of nonviral gene delivery using super paramagnetic iron oxide nanoparticles and functionalized silica nanoparticles. The experimental protocols related to these topics are described in the chapter.

  2. Polymeric nanoparticles

    PubMed Central

    Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

    2014-01-01

    Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems. PMID:24128651

  3. Precision Nanoparticles

    SciTech Connect

    John Hemminger

    2009-07-21

    A revolutionary technology that efficiently produces nanoparticles in uniform and prescribed sizes (1-100 nanometers) using supercritical fluids. INL researcher Robert Fox was joined by Idaho State University researchers Rene Rodriquez and Joshua Pak in d

  4. Bearings Incorporating Deadband Rollers

    NASA Technical Reports Server (NTRS)

    Gualtieri, Guy V.

    1996-01-01

    Bearings in high-pressure turbopump redesigned to incorporate rollers allowing limited axial motion within small deadband. Does not permit radial deadband motion. Axial deadband motion used for rotor-thrust-balance control. Design eliminates some nonlinearities in dynamics of pump rotor and assists in suppressing vibrations at harmonics of frequency of rotation.

  5. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    NASA Technical Reports Server (NTRS)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  6. Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles.

    PubMed

    Hwang, Gi Byoung; Heo, Ki Joon; Yun, Ji Ho; Lee, Jung Eun; Lee, Hee Ju; Nho, Chu Won; Bae, Gwi-Nam; Jung, Jae Hee

    2015-01-01

    Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments. PMID:25974109

  7. Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

    PubMed Central

    Yun, Ji Ho; Lee, Jung Eun; Lee, Hee Ju; Nho, Chu Won; Bae, Gwi- Nam; Jung, Jae Hee

    2015-01-01

    Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments. PMID:25974109

  8. Modulation of flavonoid metabolites in Arabidopsis thaliana through overexpression of the MYB75 transcription factor: role of kaempferol-3,7-dirhamnoside in resistance to the specialist insect herbivore Pieris brassicae

    PubMed Central

    Dicke, Marcel

    2014-01-01

    Anthocyanins and flavonols are secondary metabolites that can function in plant defence against herbivores. In Arabidopsis thaliana, anthocyanin and flavonol biosynthesis are regulated by MYB transcription factors. Overexpression of MYB75 (oxMYB75) in Arabidopsis results in increasing anthocyanin and flavonol levels which enhances plant resistance to generalist caterpillars. However, how these metabolites affect specialist herbivores has remained unknown. Performance of a specialist aphid (Brevicoryne brassicae) was unaffected after feeding on oxMYB75 plants, whereas a specialist caterpillar (Pieris brassicae) gained significantly higher body mass when feeding on this plant. An increase in anthocyanin and total flavonol glycoside levels correlated negatively with the body mass of caterpillars fed on oxMYB75 plants. However, a significant reduction of kaempferol-3,7-dirhamnoside (KRR) corresponded to an increased susceptibility of oxMYB75 plants to caterpillar feeding. Pieris brassicae caterpillars also grew less on an artificial diet containing KRR or on oxMYB75 plants that were exogenously treated with KRR, supporting KRR’s function in direct defence against this specialist caterpillar. The results show that enhancing the activity of the anthocyanin pathway in oxMYB75 plants results in re-channelling of quercetin/kaempferol metabolites which has a negative effect on the accumulation of KRR, a novel defensive metabolite against a specialist caterpillar. PMID:24619996

  9. Boron incorporation into mullite

    NASA Astrophysics Data System (ADS)

    Griesser, K. J.; Beran, A.; Voll, D.; Schneider, H.

    2008-03-01

    Boron-doped mullites were synthesized using aluminium nitrate-nonahydrate, tetraethoxysilane and boric acid in a sol gel process with subsequent annealing at 950 and 1300 °C for five hours. Two different bulk compositions with constant Al2O3 contents (60 and 70 mol%, respectively) and varying SiO2 plus B2O3 contents were investigated. X-ray powder diffraction analyses yielded a linear decrease of the lattice parameters with increasing bulk B2O3 content, which was interpreted as to be due to boron incorporation. Related to the increasing boron content, corresponding infrared spectra revealed a slight and continuous shift for most of the absorption bands. These data show that mullite is able to incorporate large amounts of boron into its structure (up to about 20 mol% B2O3 depending on the bulk composition of the starting materials). Infrared analyses suggest that boron is incorporated into the mullite structure in form of planar three-fold coordinated BO3 groups.

  10. Nanoparticle Network Formation in Nanostructured and Disordered Block Copolymer Matrices

    PubMed Central

    2010-01-01

    Incorporation of nanoparticles composed of surface-functionalized fumed silica (FS) or native colloidal silica (CS) into a nanostructured block copolymer yields hybrid nanocomposites whose mechanical properties can be tuned by nanoparticle concentration and surface chemistry. In this work, dynamic rheology is used to probe the frequency and thermal responses of nanocomposites composed of a symmetric poly(styrene-b-methyl methacrylate) (SM) diblock copolymer and varying in nanoparticle concentration and surface functionality. At sufficiently high loading levels, FS nanoparticle aggregates establish a load-bearing colloidal network within the copolymer matrix. Transmission electron microscopy images reveal the morphological characteristics of the nanocomposites under these conditions. PMID:21076678

  11. Neutron reflectivity studies of composite nanoparticle - copolymer thin films

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Hamdoun, B.; Kornilov, E. I.

    1998-06-01

    Neutron reflection was used for the investigation of a new class of copolymers - composite materials, consisting of symmetric polystyrene-polybuthylmethacrylate (PS-PBMA) diblock copolymer with incorporated nanoparticles ?-Fe 2O 3 of a few nanometers in diameter. The presence of the nanoparticles induces an elastic distortion of the copolymer matrix. From the experiments we obtained information about the lamellar order of the polymer matrix, the distribution of the nanoparticles in the film and the distortion of the interfaces caused by the nanoparticles.

  12. PLGA nanoparticles prepared by nanoprecipitation: drug loading and release studies of a water soluble drug

    Microsoft Academic Search

    Thirumala Govender; Snjezana Stolnik; Martin C. Garnett; Lisbeth Illum; Stanley S. Davis

    1999-01-01

    The nanoprecipitation technique for preparation of nanoparticles suffers the drawback of poor incorporation of water soluble drugs. The aim of this study was therefore to assess various formulation parameters to enhance the incorporation of a water soluble drug (procaine hydrochloride) into poly(dl-lactide-co-glycolide) (PLGA) nanoparticles prepared by this technique. Approaches investigated for drug incorporation efficiency enhancement included the influence of aqueous

  13. Hybrid Nanoparticles for Detection and Treatment of Cancer

    PubMed Central

    Sailor, Michael J.; Park, Ji-Ho

    2012-01-01

    There is currently considerable effort to incorporate both diagnostic and therapeutic functions into a single nanoscale system for the more effective treatment of cancer. Nanoparticles have great potential to achieve such dual functions, particularly if more than one type of nanostructure can be incorporated in a nanoassembly—referred to in this review as a hybrid nanoparticle. Here we review recent developments in the synthesis and evaluation of such hybrid nanoparticles based on two design strategies (barge vs. tanker), in which liposomal, micellar, porous silica, polymeric, viral, noble metal, and nanotube systems are incorporated either within (barge) or at the surface of (tanker) a nanoparticle. We highlight the design factors that should be considered to obtain effective nanodevices for cancer detection and treatment. PMID:22610698

  14. Incorporation of silica into baroplastic core-shell nanoparticles

    E-print Network

    Hewlett, Sheldon A

    2006-01-01

    Core-shell baroplastics are nanophase materials that exhibit pressure-induced flow at low temperatures and high pressures. Core-shell baroplastics used in this work are comprised of a low Tg poly(butyl acrylate) (PBA) core ...

  15. Dendrimer-based nanoparticles for cancer therapy

    Microsoft Academic Search

    James R. Baker Jr

    Recent work has suggested that nanoparticles in the form of dendrimers may be a keystone in the future of therapeutics. The field of oncology could soon be revolutionized by novel strategies for diagnosis and therapy employing dendrimer-based nanotherapeutics. Several aspects of cancer therapy would be involved. Diagnosis using imaging techniques such as MRI will be improved by the incorporation of

  16. Recovery and redispersion of gold nanoparticles using the self-assembly of a pH sensitive zwitterionic amphiphile.

    PubMed

    Morita-Imura, Clara; Imura, Yoshiro; Kawai, Takeshi; Shindo, Hitoshi

    2014-11-01

    The pH-responsive self-assembly of zwitterionic amphiphile C16CA was expanded to the recovery of gold (Au) nanoparticles for environmentally friendly chemistry applications. Multilayered lamellae at pH ? 4 were successfully incorporated into nanoparticles by dispersion. Redispersion of nanoparticles was achieved under basic conditions by the transition of self-assembly. PMID:25219607

  17. Antibacterial applications of silver nanoparticles synthesized by aqueous extract of Azadirachta indica (Neem) leaves.

    PubMed

    Tripathi, A; Chandrasekaran, N; Raichur, A M; Mukherjee, A

    2009-02-01

    Silver nanoparticles are known to have bactericidal effects. A new generation of dressings incorporating antimicrobial agents like silver nanoparticles is being formulated to reduce or prevent infections. The particles can be incorporated in materials and cloth rendering them sterile. Recently, it was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Apart from being environmentally friendly process, use of Neem leaves extract might add synergistic antibacterial effect of Neem leaves to the biosynthesized nanoparticles. With this hypothesis the biosynthetic production of silver nanoparticles by aqueous extract of Neem leaves and its bactericidal effect in cotton cloth against E. Coli were studied in this work. Silver nanoparticles were synthesized by short-term (1 day) and long-term (21 days) interaction of Neem extract (20% w/v) and 0.01 M AgNO3 solution in 1:4 mixing ratio. The synthesized particles were characterized by UV visible spectroscopy, transmission electron microscopy, and incorporated into cotton disks by (i) centrifuging the disks with liquid broth containing nanoparticles, (ii) in-situ coating process during synthesis, and (iii) coating with dried and purified nanoparticles. The antibacterial property of the nanoparticles coated cotton disks was studied by disk diffusion method. The effect of consecutive washing of the coated disks with distilled water on antibacterial property was also investigated. This work demonstrates the possible use of biologically synthesized silver nanoparticles by its incorporation in cloths leading them to sterilization. PMID:20055111

  18. Nanoparticle Solubility in Liquid Crystalline Defects

    NASA Astrophysics Data System (ADS)

    Whitmer, Jonathan K.; Armas-Perez, Julio C.; Joshi, Abhijeet A.; Roberts, Tyler F.; de Pablo, Juan J.

    2013-03-01

    Liquid crystalline materials often incorporate regions (defects) where the orientational ordering present in the bulk phase is disrupted. These include point hedgehogs, line disclinations, and domain boundaries. Recently, it has been shown that defects will accumulate impurities such as small molecules, monomer subunits or nanoparticles. Such an effect is thought to be due to the alleviation of elastic stresses within the bulk phase, or to a solubility gap between a nematic phase and the isotropic defect core. This presents opportunities for encapsulation and sequestration of molecular species, in addition to the formation of novel structures within a nematic phase through polymerization and nanoparticle self-assembly. Here, we examine the solubility of nanoparticles within a coarse-grained liquid crystalline phase and demonstrate the effects of nanoparticle size and surface interactions in determining sequestration into defect regions.

  19. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    NASA Astrophysics Data System (ADS)

    Yoncheva, K.; Popova, M.; Szegedi, A.; Mihaly, J.; Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V.; Pessina, F.; Valoti, M.

    2014-03-01

    Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide.

  20. Core-shell biopolymer nanoparticle delivery systems: synthesis and characterization of curcumin fortified zein-pectin nanoparticles.

    PubMed

    Hu, Kun; Huang, Xiaoxia; Gao, Yongqing; Huang, Xulin; Xiao, Hang; McClements, David Julian

    2015-09-01

    Biopolymer core-shell nanoparticles were fabricated using a hydrophobic protein (zein) as the core and a hydrophilic polysaccharide (pectin) as the shell. Particles were prepared by coating cationic zein nanoparticles with anionic pectin molecules using electrostatic deposition (pH 4). The core-shell nanoparticles were fortified with curcumin (a hydrophobic bioactive molecule) at a high loading efficiency (>86%). The resulting nanoparticles were spherical, relatively small (diameter ? 250 nm), and had a narrow size distribution (polydispersity index ? 0.24). The encapsulated curcumin was in an amorphous (rather than crystalline form) as detected by differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) and Raman spectra indicated that the encapsulated curcumin interacted with zein mainly through hydrophobic interactions. The nanoparticles were converted into a powdered form that had good water-dispersibility. These core-shell biopolymer nanoparticles could be useful for incorporating curcumin into functional foods and beverages, as well as dietary supplements and pharmaceutical products. PMID:25842338

  1. Nanoparticle-directed self-assembly of amphiphilic block-copolymers

    NASA Astrophysics Data System (ADS)

    Park, So-Jung

    2011-03-01

    The self-assembly of nanoparticles and amphiphilic polymers provides a powerful tool for the fabrication of functional composite materials for a range of applications spanning from nanofabrication to medicine. Here, we present how the incorporation of nanoparticles affects the self-assembly behavior of amphiphilic block-copolymers and how to control the morphology of nanoparticle-encapsulating polymer assemblies. Based on the approach, we have prepared various types of well-defined nanoparticle-encapsulating polymeric nanostructures, including polymersomes packed with magnetic nanoparticles and unique cavity-like quantum dot assembles. We found that the incorporation of nanoparticles drastically affects the self-assembly structure of block-copolymers by modifying the relative volume ratio between the hydrophobic block and the hydrophilic block. In addition, the nanoparticle-polymer and nanoparticle-solvent interactions impact the arrangement and the hybridization of nanoparticles in polymer matrix. These findings should form the basis for the design rules of the self-assembly of nanoparticles and polymer amphiphiles, which will allow one to create new hybrid structures with predesigned morphology and properties. Furthermore, we demonstrated that the morphology of nanoparticle-encapsulating polymer assemblies significantly affects their properties such as magnetic relaxation properties, underscoring the importance of the overall self-assembly structure and the nanoparticle arrangement in polymer matrixes. This work was supported by the NSF career award, the ARO young investigator award, and the MRSEC seed award (University of Pennsylvania).

  2. Physicochemical signatures of nanoparticle-dependent complement activation

    SciTech Connect

    Thomas, Dennis G.; Chikkagoudar, Satish; Heredia-Langner, Alejandro; Tardiff, Mark F.; Xu, Zhixiang; Hourcade, Dennis; Pham, Christine; Lanza, Gregory M.; Weinberger, Kilian Q.; Baker, Nathan A.

    2014-03-21

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we developed an in vitro hemolytic assay protocol for measuring the nanoparticle-dependent complement activity of serum samples and applied this protocol to several nanoparticle formulations that differed in size, surface charge, and surface chemistry; quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework. The robustness and predictability of the model can be improved by training the model with additional data points that are uniformly distributed in the RHA/physicochemical descriptor space and by incorporating instability effects on nanoparticle physicochemical properties into the model.

  3. Magnetic nanoparticles

    Microsoft Academic Search

    R. H Kodama

    1999-01-01

    Intrinsic properties of magnetic nanoparticles are reviewed, with special emphasis on the effects of finite size on zero-temperature spin ordering, magnetic excitations, and relaxation. Effects on zero-temperature spin ordering include moment enhancement due to band narrowing in 3d transition metal particles, surface spin disorder in ferrite particles, and multi-sublattice states in antiferromagnetic oxide particles. Magnetic excitations include discretized spin wave

  4. Earth abundant bimetallic nanoparticles for heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Senn, Jonathan F., Jr.

    Polymer exchange membrane fuel cells have the potential to replace current fossil fuel-based technologies in terms of emissions and efficiency, but CO contamination of H2 fuel, which is derived from steam methane reforming, leads to system inefficiency or failure. Solutions currently under development are bimetallic nanoparticles comprised of earth-abundant metals in different architectures to reduce the concentration of CO by PROX during fuel cell operation. Chapter One introduces the Pt-Sn and Co-Ni bimetallic nanoparticle systems, and the intermetallic and core-shell architectures of interest for catalytic evaluation. Application, theory, and studies associated with the efficacy of these nanoparticles are briefly reviewed. Chapter Two describes the concepts of the synthetic and characterization methods used in this work. Chapter Three presents the synthetic, characterization, and catalytic findings of this research. Pt, PtSn, PtSn2, and Pt 3Sn nanoparticles have been synthesized and supported on gamma-Al2O3. Pt3Sn was shown to be an effective PROX catalyst in various gas feed conditions, such as the gas mixture incorporating 0.1% CO, which displayed a light-off temperatures of ˜95°C. Co and Ni monometallic and CoNi bimetallic nanoparticles have been synthesized and characterized, ultimately leading to the development of target Co Ni core-shell nanoparticles. Proposed studies of catalytic properties of these nanoparticles in preferential oxidation of CO (PROX) reactions will further elucidate the effects of different crystallographic phases, nanoparticle-support interactions, and architecture on catalysis, and provide fundamental understanding of catalysis with nanoparticles composed of earth abundant metals in different architectures.

  5. Grain boundary engineering with gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Schmidl, F.; Katzer, C.; Michalowski, P.; Koch, S.; Tympel, V.

    2014-05-01

    We investigated high-TC grain boundary Josephson junctions with and without incorporated gold nanoparticles. Pulsed laser deposition was used for the deposition of YBa2Cu3O7-? thin films on SrTiO3 bicrystal substrates with different grain boundary angles. During the deposition process, single-crystalline nanoparticles self-assembled from a thin gold layer which was sputtered on the substrate before the YBCO deposition. The interaction between nanoparticles and thin film growth significantly influences the quality of the YBCO films [1]. The critical current density and the critical temperature of the superconducting films can be increased in a defined manner. Furthermore, the nanoparticles influence the growth conditions in the region of the grain boundary and thus the properties of the later patterned Josephson junctions. The comparison between Josephson junctions with and without nanoparticles on the same substrate shows a reduction of the critical current IC and an increase of the normal state resistance RN for all investigated types of grain boundaries in the areas with gold nanoparticles. In some cases we even found an increase of the resulting ICRN product. We present the influence of light irradiation on the properties of the Josephson junctions.

  6. Nepal CRS project incorporates.

    PubMed

    1983-01-01

    The Nepal Contraceptive Retail Sales (CRS) Project, 5 years after lauching product sales in June 1978, incorporated as a private, nonprofit company under Nepalese management. The transition was finalized in August 1983. The Company will work through a cooperative agreement with USAID/Kathmandu to complement the national family planning goals as the program continues to provide comtraceptives through retail channels at subsidized prices. Company objectives include: increase contraceptive sales by at least 15% per year; make CRS cost effective and move towards self sufficiency; and explore the possibility of marketing noncontraceptive health products to improve primary health care. After only5 years the program can point to some impressive successes. The number of retial shops selling family planning products increased from 100 in 1978 to over 8000, extending CRS product availability to 66 of the country's 75 districts. Retail sales have climbed dramatically in the 5-year period, from Rs 46,817 in 1978 to Rs 271,039 in 1982. Sales in terms of couple year protection CYP) have grown to 24,451 CYP(1982), a 36% increase over 1980 CYP. Since the beginning of the CRS marketing program, total distribution of contraceptives--through both CRS and the Family Planning Maternal and Child Haelth (FP/MCH) Project--has been increasing. While the FP/MCH program remains the largest distributor,contribution of CRS Products is increasing, indicating that CRS is creating new product acceptors. CRS market share in 1982 was 43% for condoms and 16% for oral contraceptives (OCs). CRS markets 5 products which are subsidized in order to be affordable to consumers as well as attractive to sellers. The initial products launched in June 1978 were Gulaf standard dose OCs and Dhaal lubricated colored condoms. A less expensive lubricates, plain Suki-Dhaal condom was introduced in June 1980 in an attempt to reach poorer rural populations, but rural distribution costs are excessive and Suki-Dhaal sales have never been high. In 1982 2 additional products were introduced--Nilocan (Norminest) low does OCs and Kamal Neo Sampoon foaming tablets. The CRS program recruited and trained its own sales representatives who work shop to shop, promoting products and educating retailers and consumers. An important part of the communication starategy includes consumer and retailer education. Advertising messages were developed to increase brand awareness, create demand, educate consumers about side effects of OCs, and to identify contraceptives as a means of adequately space children. PMID:12312964

  7. Pure drug nanoparticles in tablets: what are the dissolution limitations?

    Microsoft Academic Search

    Desmond Heng; Keiko Ogawa; David J. Cutler; Hak-Kim Chan; Judy A. Raper; Lin Ye; Jimmy Yun

    2010-01-01

    There has been increasing interests for drug companies to incorporate drug nanoparticles into their existing formulations.\\u000a However, technical knowledge in this area is still in its infancy and more study needs to be done to stimulate growth in this\\u000a fledging field. There is a need to scrutinize the performance of pure drug nanoparticles in tablets, particularly relating\\u000a formulation variables to

  8. Hybrid collagen-based hydrogels with embedded montmorillonite nanoparticles.

    PubMed

    Nistor, Manuela Tatiana; Vasile, Cornelia; Chiriac, Aurica P

    2015-08-01

    Montmorillonite nanoparticles have been physically incorporated within a crosslinked collagen/poly(N-isopropyl acrylamide) network in order to adjust the properties of the stimuli-responsive hybrid systems. The research underlines both the influence of hydrogel composition and nanoparticle type on hybrid hydrogel properties. The dispersion of the montmorillonite nanoparticles in polymeric matrix have been visualized by SEM, TEM and AFM techniques and quantitatively and qualitatively estimated using near infrared chemical imaging. The electrical charge of the nanoparticles influenced the polymeric chain arrangement and the pore size. The morphologies of the nanoparticulated layers are partially exfoliated or intercalated and uniformly dispersed through the polymeric semi-interpenetrated network based on collagen and poly(N-isopropyl acrylamide). The hybrid hydrogels exhibit pseudoplastic behavior and the addition of nanoparticles has resulted in the increase of the complex viscosity. The adhesion capacity was affected mainly by the presence of organically modified montmorillonites. PMID:26042709

  9. Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system

    Microsoft Academic Search

    Linlin Li; Dong Chen; Yanqi Zhang; Zhengtao Deng; Xiangling Ren; Xianwei Meng; Fangqiong Tang; Jun Ren; Lin Zhang

    2007-01-01

    An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties

  10. Influence of nanoparticle surface modification on the electrical behaviour of polyethylene nanocomposites

    Microsoft Academic Search

    Dongling Ma; Treese A. Hugener; Richard W. Siegel; Anna Christerson; Eva Mårtensson; Carina Önneby; Linda S. Schadler

    2005-01-01

    In this study, we present the results of the influence of surface modification of TiO2 nanoparticles on the short-term breakdown strength and space charge distribution of low-density polyethylene (LDPE). A polar silane coupling agent N-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPS) was used for the nanoparticle surface modification. Despite agglomeration and a poor interface compared to untreated nanoparticles, it was found that the incorporation

  11. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    NASA Astrophysics Data System (ADS)

    Anantachaisilp, Suranan; Meejoo Smith, Siwaporn; Treetong, Alongkot; Pratontep, Sirapat; Puttipipatkhachorn, Satit; Rungsardthong Ruktanonchai, Uracha

    2010-03-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of ?-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812® as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the ?-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance (1H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of ?-oryzanol inside the lipid nanoparticles, the 1H-NMR revealed that the chemical shifts of the liquid lipid in ?-oryzanol loaded systems were found at rather higher field than those in ?-oryzanol free systems, suggesting incorporation of ?-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of ?-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of ?-oryzanol and lipids (solid and liquid) inside the lipid nanoparticle systems are proposed.

  12. Block copolymer mediated stabilization of sub-5 nm superparamagnetic nickel nanoparticles in an aqueous medium

    Microsoft Academic Search

    Tanushree Bala; Robert Denis Gunning; Munuswamy Venkatesan; Jeffrey F. Godsell; Saibal Roy; Kevin M. Ryan

    2009-01-01

    This paper presents a facile method for decreasing the size of water dispersible Ni nanoparticles from 30 to 3 nm by the incorporation of a passivating surfactant combination of pluronic triblock copolymer and oleic acid into a wet chemical reduction synthesis. A detailed study revealed that the size of the Ni nanoparticles is not only critically governed by the concentration

  13. Solid lipid nanoparticles (SLN) for controlled drug delivery – a review of the state of the art

    Microsoft Academic Search

    Rainer H. Müller; Karsten Mäder; Sven Gohla

    2000-01-01

    Solid lipid nanoparticles (SLN) introduced in 1991 represent an alternative carrier system to traditional colloidal carriers, such as emulsions, liposomes and polymeric micro- and nanoparticles. SLN combine advantages of the traditional systems but avoid some of their major disadvantages. This paper reviews the present state of the art regarding production techniques for SLN, drug incorporation, loading capacity and drug release,

  14. Lipid nanoparticles for transdermal delivery of flurbiprofen: formulation, in vitro, ex vivo and in vivo studies

    Microsoft Academic Search

    Kesavan Bhaskar; Jayaraman Anbu; Velayutham Ravichandiran; Vobalaboina Venkateswarlu; Yamsani Madhusudan Rao

    2009-01-01

    The aim of the study is to prepare aqueous dispersions of lipid nanoparticles – flurbiprofen solid lipid nanoparticles (FLUSLN) and flurbiprofen nanostructured lipid carriers (FLUNLC) by hot homogenization followed by sonication technique and then incorporated into the freshly prepared hydrogels for transdermal delivery. They are characterized for particle size, for all the formulations, more than 50% of the particles were

  15. Analysis of Adhesion and Fracture Energy of NanoParticle Silver in Electronics Packaging Applications

    Microsoft Academic Search

    Sung Chul Joo; Daniel F. Baldwin

    2010-01-01

    Nano-particle silver (NPS) conductors are increasingly being investigated for package level electronics applications. Unlike traditional thick film materials and conductive inks, nano-particle conductors often do not incorporate compounds to promote interfacial adhesion such as binders used in thick films and polymer adhesives used in conductive inks as these adhesion promoters can degrade the electrical performance. The NPS is concerned with

  16. Cellulose Acetate Fibers with Fluorescing Nanoparticles for Anti-counterfeiting and pH-sensing Applications

    Microsoft Academic Search

    Erin Hendrick; Margaret Frey; Erik Herz; Ulrich Wiesner

    2010-01-01

    Fluorescent silica nanoparticles, Cornell dots (C dots), were incorporated into electrospun cellulose acetate (CA) fibers. Two types of C dots were used in this study. The first type was comprised of a fluorescent dye-containing silica core surrounded by a silica shell. These nanoparticles fluoresce at 572 nm when exposed to 541 nm light. Increasing C dot loading in the spinning

  17. Controlled cobalt doping in biogenic magnetite nanoparticles.

    PubMed

    Byrne, J M; Coker, V S; Moise, S; Wincott, P L; Vaughan, D J; Tuna, F; Arenholz, E; van der Laan, G; Pattrick, R A D; Lloyd, J R; Telling, N D

    2013-06-01

    Cobalt-doped magnetite (CoxFe3 -xO4) nanoparticles have been produced through the microbial reduction of cobalt-iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe(2+) site with Co(2+), with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  18. Controlled cobalt doping in biogenic magnetite nanoparticles

    PubMed Central

    Byrne, J. M.; Coker, V. S.; Moise, S.; Wincott, P. L.; Vaughan, D. J.; Tuna, F.; Arenholz, E.; van der Laan, G.; Pattrick, R. A. D.; Lloyd, J. R.; Telling, N. D.

    2013-01-01

    Cobalt-doped magnetite (CoxFe3 ?xO4) nanoparticles have been produced through the microbial reduction of cobalt–iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe2+ site with Co2+, with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  19. Ultrasonic properties of nanoparticles-liquid suspensions.

    PubMed

    Yadav, R R; Mishra, Giridhar; Yadawa, P K; Kor, S K; Gupta, A K; Raj, Baldev; Jayakumar, T

    2008-11-01

    A polymer colloidal solution having dispersed nanoparticles of Cu and Au metals have been developed using a novel chemical method. Average size of the nanoparticles could be varied in the 4-10 nm range by conducting the reaction at an elevated temperature of 50-70 degrees C. Colloidal solutions of representative concentrations of 0.1-2.0 wt% Cu/Au contents in the primary solutions are used to study the modified ultrasonic attenuation and ultrasonic velocity in PVA polymer molecules on incorporating the Cu/Au particles. A characteristic behaviour of the ultrasonic velocity and the attenuation are observed at the particular temperature/particle concentration. The results demonstrate that the primary reaction during the nanoparticles-PVA colloidal formation occurs in divided groups in small micelles. The results are analyzed predicting the enhanced thermal conductivity of the samples. PMID:18657282

  20. Piezoelectric Nanoparticle-Polymer Composite Materials

    NASA Astrophysics Data System (ADS)

    McCall, William Ray

    Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

  1. Stabilisation effects of superparamagnetic nanoparticles on clustering in nanocomposite microparticles and on magnetic behaviour

    NASA Astrophysics Data System (ADS)

    Mandel, K.; Hutter, F.; Gellermann, C.; Sextl, G.

    2013-04-01

    Superparamagnetic nanoparticles of magnetite were coprecipitated from iron salts, dispersed with nitric acid and stabilised either by lactic acid (LA) or by a polycarboxylate-ether polymer (MELPERS4343, MP). The differently stabilised nanoparticles were incorporated into a silica matrix to form nanocomposite microparticles. The silica matrix was prepared either from tetraethylorthosilicate (TEOS) or from an aqueous sodium silicate (water glass) solution. Stabilisation of nanoparticles had a crucial influence on microparticle texture and nanoparticle distribution in the silica matrix. Magnetic measurements in combination with transmission electron microscopy (TEM) investigations suggest a uniform magnetic interaction of nanoparticles in case of LA stabilisation and magnetically interacting nanoparticle clusters of different sizes in case of MP stabilisation. Splitting of blocking temperature (TB) and irreversible temperature (Tir) in zero field cooled (ZFC) and field cooled (FC) measurements is discussed in terms of nanoparticle clustering.

  2. Crystallization of hollow mesoporous silica nanoparticles.

    PubMed

    Drisko, Glenna L; Carretero-Genevrier, Adrian; Perrot, Alexandre; Gich, Martí; Gàzquez, Jaume; Rodriguez-Carvajal, Juan; Favre, Luc; Grosso, David; Boissière, Cédric; Sanchez, Clément

    2015-03-11

    Complex 3D macrostructured nanoparticles are transformed from amorphous silica into pure polycrystalline ?-quartz using catalytic quantities of alkaline earth metals as devitrifying agent. Walls as thin as 10 nm could be crystallized without losing the architecture of the particles. The roles of cation size and the mol% of the incorporated devitrifying agent in crystallization behavior are studied, with Mg(2+), Ca(2+), Sr(2+) and Ba(2+) all producing pure ?-quartz under certain conditions. PMID:25503642

  3. In vitro and in vivo anti-tumor activities of a gemcitabine derivative carried by nanoparticles.

    PubMed

    Sloat, Brian R; Sandoval, Michael A; Li, Dong; Chung, Woon-Gye; Lansakara-P, Dharmika S P; Proteau, Philip J; Kiguchi, Kaoru; DiGiovanni, John; Cui, Zhengrong

    2011-05-16

    Gemcitabine (Gemzar(®)) is the first line treatment for pancreatic cancer and often used in combination therapy for non-small cell lung, ovarian, and metastatic breast cancers. Although extremely toxic to a variety of tumor cells in culture, the clinical outcome of gemcitabine treatment still needs improvement. In the present study, a new gemcitabine nanoparticle formulation was developed by incorporating a previously reported stearic acid amide derivative of gemcitabine into nanoparticles prepared from lecithin/glyceryl monostearate-in-water emulsions. The stearoyl gemcitabine nanoparticles were cytotoxic to tumor cells in culture, although it took a longer time for the gemcitabine in the nanoparticles to kill tumor cells than for free gemcitabine. In mice with pre-established model mouse or human tumors, the stearoyl gemcitabine nanoparticles were significantly more effective than free gemcitabine in controlling the tumor growth. PEGylation of the gemcitabine nanoparticles with polyethylene glycol (2000) prolonged the circulation of the nanoparticles in blood and increased the accumulation of the nanoparticles in tumor tissues (>6-fold), but the PEGylated and un-PEGylated gemcitabine nanoparticles showed similar anti-tumor activity in mice. Nevertheless, the nanoparticle formulation was critical for the stearoyl gemcitabine to show a strong anti-tumor activity. It is concluded that for the gemcitabine derivate-containing nanoparticles, cytotoxicity data in culture may not be used to predict their in vivo anti-tumor activity, and this novel gemcitabine nanoparticle formulation has the potential to improve the clinical outcome of gemcitabine treatment. PMID:21371545

  4. In vitro and in vivo anti-tumor activities of a gemcitabine derivative carried by nanoparticles

    PubMed Central

    Sloat, Brian R.; Sandoval, Michael A.; Li, Dong; Chung, Woon-Gye; Lansakara-P., Dharmika S. P.; Proteau, Philip J.; Kiguchi, Kaoru; DiGiovanni, John; Cui, Zhengrong

    2011-01-01

    Gemcitabine (Gemzar®) is the first line treatment for pancreatic cancer and often used in combination therapy for non-small cell lung, ovarian, and metastatic breast cancers. Although extremely toxic to a variety of tumor cells in culture, the clinical outcome of gemcitabine treatment still needs improvement. In the present study, a new gemcitabine nanoparticle formulation was developed by incorporating a previously reported stearic acid amide derivative of gemcitabine into nanoparticles prepared from lecithin/glyceryl monostearate-in-water emulsions. The stearoyl gemcitabine nanoparticles were cytotoxic to tumor cells in culture, although it took a longer time for the gemcitabine in the nanoparticles to kill tumor cells than for free gemcitabine. In mice with pre-established model mouse or human tumors, the stearoyl gemcitabine nanoparticles were significantly more effective than free gemcitabine in controlling the tumor growth. PEGylation of the gemcitabine nanoparticles with polyethylene glycol (2000) prolonged the circulation of the nanoparticles in blood and increased the accumulation of the nanoparticles in tumor tissues (> 6-fold), but the PEGylated and un-PEGylated gemcitabine nanoparticles showed similar anti-tumor activity in mice. Nevertheless, the nanoparticle formulation was critical for the stearoyl gemcitabine to show a strong anti-tumor activity. It is concluded that for the gemcitabine derivate-containing nanoparticles, cytotoxicity data in culture may not be used to predict their in vivo anti-tumor activity, and this novel gemcitabine nanoparticle formulation has the potential to improve the clinical outcome of gemcitabine treatment. PMID:21371545

  5. Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces

    PubMed Central

    Liu, Guoliang; Eichelsdoerfer, Daniel J.; Rasin, Boris; Zhou, Yu; Brown, Keith A.; Liao, Xing; Mirkin, Chad A.

    2013-01-01

    Although nanoparticles with exquisite properties have been synthesized for a variety of applications, their incorporation into functional devices is challenging owing to the difficulty in positioning them at specified sites on surfaces. In contrast with the conventional synthesis-then-assembly paradigm, scanning probe block copolymer lithography can pattern precursor materials embedded in a polymer matrix and synthesize desired nanoparticles on site, offering great promise for incorporating nanoparticles into devices. This technique, however, is extremely limited from a materials standpoint. To develop a materials-general method for synthesizing nanoparticles on surfaces for broader applications, a mechanistic understanding of polymer-mediated nanoparticle formation is crucial. Here, we design a four-step synthetic process that enables independent study of the two most critical steps for synthesizing single nanoparticles on surfaces: phase separation of precursors and particle formation. Using this process, we elucidate the importance of the polymer matrix in the diffusion of metal precursors to form a single nanoparticle and the three pathways that the precursors undergo to form nanoparticles. Based on this mechanistic understanding, the synthetic process is generalized to create metal (Au, Ag, Pt, and Pd), metal oxide (Fe2O3, Co2O3, NiO, and CuO), and alloy (AuAg) nanoparticles. This mechanistic understanding and resulting process represent a major advance in scanning probe lithography as a tool to generate patterns of tailored nanoparticles for integration with solid-state devices. PMID:23277538

  6. Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces.

    PubMed

    Liu, Guoliang; Eichelsdoerfer, Daniel J; Rasin, Boris; Zhou, Yu; Brown, Keith A; Liao, Xing; Mirkin, Chad A

    2013-01-15

    Although nanoparticles with exquisite properties have been synthesized for a variety of applications, their incorporation into functional devices is challenging owing to the difficulty in positioning them at specified sites on surfaces. In contrast with the conventional synthesis-then-assembly paradigm, scanning probe block copolymer lithography can pattern precursor materials embedded in a polymer matrix and synthesize desired nanoparticles on site, offering great promise for incorporating nanoparticles into devices. This technique, however, is extremely limited from a materials standpoint. To develop a materials-general method for synthesizing nanoparticles on surfaces for broader applications, a mechanistic understanding of polymer-mediated nanoparticle formation is crucial. Here, we design a four-step synthetic process that enables independent study of the two most critical steps for synthesizing single nanoparticles on surfaces: phase separation of precursors and particle formation. Using this process, we elucidate the importance of the polymer matrix in the diffusion of metal precursors to form a single nanoparticle and the three pathways that the precursors undergo to form nanoparticles. Based on this mechanistic understanding, the synthetic process is generalized to create metal (Au, Ag, Pt, and Pd), metal oxide (Fe(2)O(3), Co(2)O(3), NiO, and CuO), and alloy (AuAg) nanoparticles. This mechanistic understanding and resulting process represent a major advance in scanning probe lithography as a tool to generate patterns of tailored nanoparticles for integration with solid-state devices. PMID:23277538

  7. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    SciTech Connect

    Yoncheva, K., E-mail: krassi.yoncheva@gmail.com [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Popova, M. [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Szegedi, A.; Mihaly, J. [Institute of Nanochemistry and Catalysis, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út. 59-67, 1025 Budapest (Hungary); Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V. [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Pessina, F.; Valoti, M. [Dipartimento di Scienze della Vita, Universita di Siena, via Aldo Moro 2, Siena (Italy)

    2014-03-15

    Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide. -- Graphical abstract: Silica mesoporous MCM-41 particles were amino-functionalized, loaded with budesonide and post-coated with bioadhesive polymer (carbopol) in order to achieve prolonged residence of anti-inflammatory drug in GIT. Highlights: • Higher drug loading in amino-functionalized mesoporous silica. • Amino-functionalization and post-coating of the nanoparticles sustained drug release. • Achievement of higher cytoprotective effect with drug loaded into the nanoparticles.

  8. Modified natural nanoparticles as contrast agents for medical imaging

    PubMed Central

    Cormode, David P.; Jarzyna, Peter A.; Mulder, Willem J. M.; Fayad, Zahi A.

    2009-01-01

    The development of novel and effective contrast agents is one of the drivers of the ongoing improvement in medical imaging. Many of the new agents reported are nanoparticle-based. There are a variety of natural nanoparticles known, e.g. lipoproteins, viruses or ferritin. Natural nanoparticles have advantages as delivery platforms such as biodegradability. In addition, our understanding of natural nanoparticles is quite advanced, allowing their adaptation as contrast agents. They can be labeled with small molecules or ions such as Gd3+ to act as contrast agents for magnetic resonance imaging, 18F to act as positron emission tomography contrast agents or fluorophores to act as contrast agents for fluorescence techniques. Additionally, inorganic nanoparticles such as iron oxide, gold nanoparticles or quantum dots can be incorporated to add further contrast functionality. Furthermore, these natural nanoparticle contrast agents can be rerouted from their natural targets via the attachment of targeting molecules. In this review, we discuss the various modified natural nanoparticles that have been exploited as contrast agents. PMID:19900496

  9. Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles

    SciTech Connect

    Gilbert, Benjamin

    2008-10-01

    The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.

  10. Nanoparticles for Biomedical Imaging

    Microsoft Academic Search

    Satish K. Nune; Padmaja Gunda; Praveen K. Thallapally; Ying-Ying Lin; Laird M. Forrest; Cory J. Berkland

    2009-01-01

    Background: Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 to 100 nm in diameter possess dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for

  11. Nanoparticles by Laser Ablation

    Microsoft Academic Search

    N. G. Semaltianos

    2010-01-01

    This review concerns nanoparticles collected in the form of nanopowder or a colloidal solution by laser ablating a solid target that lies in a gaseous or a liquid environment. The paper discusses the advantages of the method as compared with other methods for nanoparticle synthesis, outlines the factors on which the properties of the produced nanoparticles depend, explains the mechanisms

  12. CCMR: Bimetallic Nanoparticle Catalysis

    NSDL National Science Digital Library

    Chong, Hahn

    2010-08-15

    Bimetallic nanoparticles are of great interest in scientific research due to their large surface to volume ratios and surface restructuring that may occur during catalysis. Our goals were to synthesize different bimetallic nanoparticles and test their catalytic abilities for use in future experiments. The nanoparticles we concentrated on were Au/Ag alloy, Au/Cu alloy, and Au/Pd core-shell.

  13. Cationic additives in nanosystems activate cytotoxicity and inflammatory response of human neutrophils: lipid nanoparticles versus polymeric nanoparticles

    PubMed Central

    Hwang, Tsong-Long; Aljuffali, Ibrahim A; Lin, Chwan-Fwu; Chang, Yuan-Ting; Fang, Jia-You

    2015-01-01

    This report compares the effect of lipid and polymeric nanoparticles upon human neutrophils in the presence of cationic surfactants. Nanostructured lipid carriers and poly(lactic-co-glycolic) acid nanoparticles were manufactured as lipid and polymeric systems, respectively. Some cytotoxic and proinflammatory mediators such as lactate dehydrogenase (LDH), elastase, O2•?, and intracellular Ca2+ were examined. The nanoparticles showed a size of 170–225 nm. Incorporation of cetyltrimethylammonium bromide or soyaethyl morpholinium ethosulfate, the cationic surfactant, converted zeta potential from a negative to a positive charge. Nanoparticles without cationic surfactants revealed a negligible change on immune and inflammatory responses. Cationic surfactants in both nanoparticulate and free forms induced cell death and the release of mediators. Lipid nanoparticles generally demonstrated a greater response compared to polymeric nanoparticles. The neutrophil morphology observed by electron microscopy confirmed this trend. Cetyltrimethylammonium bromide as the coating material showed more significant activation of neutrophils than soyaethyl morpholinium ethosulfate. Confocal microscope imaging displayed a limited internalization of nanoparticles into neutrophils. It is proposed that cationic nanoparticles interact with the cell membrane, triggering membrane disruption and the following Ca2+ influx. The elevation of intracellular Ca2+ induces degranulation and oxidative stress. The consequence of these effects is cytotoxicity and cell death. Caution should be taken when selecting feasible nanoparticulate formulations and cationic additives for consideration of applicability and toxicity. PMID:25609950

  14. Core-Shell Composite Nanoparticles: Synthesis, Characterization, and Applications

    NASA Astrophysics Data System (ADS)

    Sanyal, Sriya

    Nanoparticles are ubiquitous in various fields due to their unique properties not seen in similar bulk materials. Among them, core-shell composite nanoparticles are an important class of materials which are attractive for their applications in catalysis, sensing, electromagnetic shielding, drug delivery, and environmental remediation. This dissertation focuses on the study of core-shell type of nanoparticles where a polymer serves as the core and inorganic nanoparticles are the shell. This is an interesting class of supramolecular building blocks and can "exhibit unusual, possibly unique, properties which cannot be obtained simply by co-mixing polymer and inorganic particles". The one-step Pickering emulsion polymerization method was successfully developed and applied to synthesize polystyrene-silica core-shell composite particles. Possible mechanisms of the Pickering emulsion polymerization were also explored. The silica nanoparticles were thermodynamically favorable to self-assemble at liquid-liquid interfaces at the initial stage of polymerization and remained at the interface to finally form the shells of the composite particles. More importantly, Pickering emulsion polymerization was employed to synthesize polystyrene/poly(N-isopropylacrylamide) (PNIPAAm)-silica core-shell nanoparticles with N-isopropylacrylamide incorporated into the core as a co-monomer. The composite nanoparticles were temperature sensitive and could be up-taken by human prostate cancer cells and demonstrated effectiveness in drug delivery and cancer therapy. Similarly, by incorporating poly-2-(N,N)-dimethylamino)ethyl methacrylate (PDMA) into the core, pH sensitive core-shell composite nanoparticles were synthesized and applied as effective carriers to release a rheological modifier upon a pH change. Finally, the research focuses on facile approaches to engineer the transition of the temperature-sensitive particles and develop composite core-shell nanoparticles with a metallic shell.

  15. Nanoparticles for transcutaneous vaccination

    PubMed Central

    Hansen, Steffi; Lehr, Claus?Michael

    2012-01-01

    Summary The living epidermis and dermis are rich in antigen presenting cells (APCs). Their activation can elicit a strong humoral and cellular immune response as well as mucosal immunity. Therefore, the skin is a very attractive site for vaccination, and an intradermal application of antigen may be much more effective than a subcutaneous or intramuscular injection. However, the stratum corneum (SC) is a most effective barrier against the invasion of topically applied vaccines. Products which have reached the stage of clinical testing, avoid this problem by injecting the nano?vaccine intradermally or by employing a barrier disrupting method and applying the vaccine to a relatively large skin area. Needle?free vaccination is desirable from a number of aspects: ease of application, improved patient acceptance and less risk of infection among them. Nanocarriers can be designed in a way that they can overcome the SC. Also incorporation into nanocarriers protects instable antigen from degradation, improves uptake and processing by APCs, and facilitates endosomal escape and nuclear delivery of DNA vaccines. In addition, sustained release systems may build a depot in the tissue gradually releasing antigen which may avoid booster doses. Therefore, nanoformulations of vaccines for transcutaneous immunization are currently a very dynamic field of research. Among the huge variety of nanocarrier systems that are investigated hopes lie on ultra?flexible liposomes, superfine rigid nanoparticles and nanocarriers, which are taken up by hair follicles. The potential and pitfalls associated with these three classes of carriers will be discussed. PMID:21854553

  16. Synthesis, characterization and UV-shielding property of polystyrene-embedded CeO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Kang-Qiang; Kuang, Cheng-Xiu; Zhong, Ming-Qiang; Shi, Yan-Qin; Chen, Feng

    2013-10-01

    A cerium-triethanolamine (TEA) complex was prepared and used as the precursor to synthesize CeO2 nanoparticles. It was mixed with styrene (St) in aqueous solution and hydrolysized to generate CeO2 nanoparticles. In situ emulsion polymerization of the monomer was followed in one pot. The CeO2 nanoparticles were incorporated into polystyrene (PS) matrix and dispersed homogeneously, with an average crystallite size of 3-5 nm and a band gap at 3.01 eV. Meanwhile, the embedding of the CeO2 nanoparticles can enhance UV-shielding property of PS.

  17. In Vivo Sustained Release of siRNA from Solid Lipid Nanoparticles

    PubMed Central

    Lobovkina, Tatsiana; Jacobson, Gunilla B.; Gonzalez, Emilio Gonzalez; Hickerson, Robyn P.; Leake, Devin; Kaspar, Roger L.; Contag, Christopher H.; Zare, Richard N.

    2011-01-01

    Small interfering RNA (siRNA) is a highly potent drug in gene-based therapy with a challenge of being delivered in a sustained manner. Nanoparticle drug delivery systems allow for incorporating and controlled release of therapeutic payloads. We demonstrate that solid lipid nanoparticles can incorporate and provide sustained release of siRNA. Tristearin solid lipid nanoparticles, made by nanoprecipitation, were loaded with siRNA (4.4–5.5 weight percent loading ratio) using a hydrophobic ion pairing approach that employs the cationic lipid DOTAP. Intradermal injection of these nanocarriers in mouse footpads resulted in prolonged siRNA release over a period of 10–13 days. In vitro cell studies showed that the released siRNA retained its activity. Nanoparticles developed in this study offer an alternative approach to polymeric nanoparticles for encapsulation and sustained delivery of siRNA with the advantage of being prepared from physiologically well-tolerated materials. PMID:22077198

  18. Preparation, characterization, and in vivo evaluation of mitoxantrone-loaded, folate-conjugated albumin nanoparticles.

    PubMed

    Zhang, Liang-ke; Hou, Shi-xiang; Zhang, Jing-qin; Hu, Wen-jing; Wang, Cheng-yuan

    2010-08-01

    Folic acid was covalently conjugated to bovine serum albumin nanoparticles (BSANP) to target the nanoparticles to SKOV3 cells expressing folate receptors. Mitoxantrone was incorporated into the folate-conjugated albumin nanoparticles, and the final nanoparticle size was 68 nm, as measured by a laser light scattering particle analyzer. The cytotoxic activity of mitoxantrone- loaded, folate-conjugated albumin nanoparticles (MTO-BSANP-folate), which was quantitated by (3)H-thymidine incorporation, was higher than mitoxantrone-loaded BSANP (MTO-BSANP) and MTO solution, and could be inhibited by free folic acid. MTO-BSANPfolate may be endocytosed via the folate receptor on the surface of SKOV3 cells. MTO-BSANPfolate also inhibited tumor growth better than the MTO-BSANP and MTO solution in vivo. These results indicate that folate-conjugated BSANP may have therapeutic potential as a vector for anticancer drugs in cancer chemotherapy. PMID:20803122

  19. The Effect of Nanoparticle Radius of Gyration on the Diffusion of Polystyrene in a Nanocomposite

    NASA Astrophysics Data System (ADS)

    Imel, Adam; Miller, Brad; Holly, Wade; Baskaran, Durairaj; Mays, J. W.; Dadmun, Mark D.

    2014-03-01

    Controlling the dispersion of nanoparticles throughout a polymer matrix is difficult. We have found that nanoparticle dispersion can be achieved by incorporating soft, organic nanoparticles with complementary chemical moieties, thus achieving favorable enthalpic interactions. The rational design of soft nanoparticles can create an interface that allows interpenetration of the polymer chains and particles reducing the depletion of entropy that is the main contributing force to the flocculation of nanoparticles. The nanoparticles are produced by intra-molecularly crosslinking a single polystyrene chain via a nano-emulsion technique with divinyl benzene. This synthetic approach allows the effects from structure, size and softness of the nanoparticle to be examined as they contribute to the dynamics of the polymer matrix by varying the crosslink density. This report focuses on the effect that these nanoparticles have on the diffusion coefficient of polystyrene. Neutron reflectivity was used to monitor the interdiffusion of deuterated polystyrene and protonated polystyrene with and without the soft nanoparticles in the respective layers. It has been proposed that the ratio of the radius of gyration (Rg) of the polymer chain to the nanoparticle controls the dynamics, thus the molecular weights of the matrix in this study have been varied from 535, 173, to 68 kg/mol. Initial results suggest when the Rg of the polymer is larger than that of the nanoparticle Rg the dynamics are impacted the most.

  20. Structural integrity enhancement of graphite fiber composites using nanoparticles

    Microsoft Academic Search

    Han Sang Kim

    2007-01-01

    Graphite fibrous polymer composites with graphite nanoplatelets or single wall carbon nanotubes have been processed and tested for the mechanical and the electrical properties. Spray methods to incorporate nanoparticles into the composites were explored as a scalable processing method. Processing-microstructure-property relationship shows the promising aspects and the limitation of this processing method.

  1. Terminal Supraparticle Assemblies from Similarly Charged Protein Molecules and Nanoparticles

    PubMed Central

    Park, Jai Il; Nguyen, Trung Dac; de Queirós Silveira, Gleiciani; Bahng, Joong Hwan; Srivastava, Sudhanshu; Sun, Kai; Zhao, Gongpu; Zhang, Peijun; Glotzer, Sharon C.; Kotov, Nicholas A.

    2015-01-01

    Self-assembly of proteins and inorganic nanoparticles into terminal assemblies makes possible a large family of uniformly sized hybrid colloids. These particles can be compared in terms of utility, versatility and multifunctionality to other known types of terminal assemblies. They are simple to make and offer theoretical tools for designing their structure and function. To demonstrate such assemblies, we combine cadmium telluride nanoparticles with cytochrome C protein and observe spontaneous formation of spherical supraparticles with a narrow size distribution. Such self-limiting behaviour originates from the competition between electrostatic repulsion and non-covalent attractive interactions. Experimental variation of supraparticle diameters for several assembly conditions matches predictions obtained in simulations. Similar to micelles, supraparticles can incorporate other biological components as exemplified by incorporation of nitrate reductase. Tight packing of nanoscale components enables effective charge and exciton transport in supraparticles as demonstrated by enzymatic nitrate reduction initiated by light absorption in the nanoparticle. PMID:24845400

  2. Terminal supraparticle assemblies from similarly charged protein molecules and nanoparticles

    NASA Astrophysics Data System (ADS)

    Park, Jai Il; Nguyen, Trung Dac; de Queirós Silveira, Gleiciani; Bahng, Joong Hwan; Srivastava, Sudhanshu; Zhao, Gongpu; Sun, Kai; Zhang, Peijun; Glotzer, Sharon C.; Kotov, Nicholas A.

    2014-05-01

    Self-assembly of proteins and inorganic nanoparticles into terminal assemblies makes possible a large family of uniformly sized hybrid colloids. These particles can be compared in terms of utility, versatility and multifunctionality to other known types of terminal assemblies. They are simple to make and offer theoretical tools for designing their structure and function. To demonstrate such assemblies, we combine cadmium telluride nanoparticles with cytochrome C protein and observe spontaneous formation of spherical supraparticles with a narrow size distribution. Such self-limiting behaviour originates from the competition between electrostatic repulsion and non-covalent attractive interactions. Experimental variation of supraparticle diameters for several assembly conditions matches predictions obtained in simulations. Similar to micelles, supraparticles can incorporate other biological components as exemplified by incorporation of nitrate reductase. Tight packing of nanoscale components enables effective charge and exciton transport in supraparticles and bionic combination of properties as demonstrated by enzymatic nitrate reduction initiated by light absorption in the nanoparticle.

  3. De-alloyed platinum nanoparticles

    DOEpatents

    Strasser, Peter (Houston, TX); Koh, Shirlaine (Houston, TX); Mani, Prasanna (Houston, TX); Ratndeep, Srivastava (Houston, TX)

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  4. INCORPORATING ANTHROPOGENIC PROCESSES IN SOIL CLASSIFICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter considers the need for incorporating anthropogenic processes in soil classification systems, describes fundamental approaches to soil classification and their underlying concepts that affect the incorporation of anthropogenic processes, and proposes possible approaches to incorporating ...

  5. Lipid nanoparticles for the topical delivery of retinoids and derivatives.

    PubMed

    Morales, Javier O; Valdés, Karina; Morales, Javier; Oyarzun-Ampuero, Felipe

    2015-01-01

    Retinoids are lipophilic compounds that are highly used in cosmetics/therapeutics for skin disorders. Conventional formulations are limited by poor water solubility, high chemical/photochemical instability and the irritation of retinoids. Interestingly, lipid nanoparticles enable the administration of retinoids in aqueous media, providing drug stabilization and controlled release. Recently, it has been demonstrated that retinoids in solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules can decrease degradation, improve targeting and enhance efficacy for the treatment of skin disorders. This article focuses on the formulation, fabrication, characterization and in vitro/in vivo evaluation of solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules loaded with retinoids for skin administration. Furthermore, the incorporation of these lipid nanoparticles into secondary vehicles is discussed. PMID:25600970

  6. Preparation, characterization and application of pyrene-loaded methoxy poly(ethylene glycol)–poly(lactic acid) copolymer nanoparticles

    Microsoft Academic Search

    Yan Zhang; Qizhi Zhang; Liusheng Zha; Wuli Yang; Changchun Wang; Xinguo Jiang; Shoukuan Fu

    2004-01-01

    Pyrene-loaded biodegradable polymer nanoparticles were prepared by incorporating pyrene into the polymer nanoparticles formulated from amphiphilic diblock copolymer, methoxy poly(ethylene glycol)–poly(lactic acid) (MePEG–PLA). Their morphological structure and physical properties were characterized by nuclear magnetic resonance (NMR), dynamic light scattering, fluorescence spectroscopy, transmission electronic microscopy and zeta potential measurements. Further, MePEG–PLA nanoparticles containing pyrene as fluorescent marker were administered intranasally to

  7. incorporation of clodronate-liposomes

    Microsoft Academic Search

    Carsten B. SchmidtWeber; Michael Rittig; Eberhard Buchner; Ingeborg Hauser; Frank Emmrich; Raimund W. Kinne

    The present study was performed to elu- cidate whether sterically stabilized liposomes laden with clodronate, which lead to depletion of macro- phages (M4s) and amelioration of experimental autoimmune arthritis in vivo, selectively affect cells of the mlineage in vitro. The rates of incorporation of drug-free, fluorescent liposomes and the rates of cell death following exposure to clodronate- liposomes were assessed

  8. Incorporating Argumentation through Forensic Science

    ERIC Educational Resources Information Center

    Wheeler, Lindsay B.; Maeng, Jennifer L.; Smetana, Lara K.

    2014-01-01

    This article outlines how to incorporate argumentation into a forensic science unit using a mock trial. Practical details of the mock trial include: (1) a method of scaffolding students' development of their argument for the trial, (2) a clearly outlined set of expectations for students during the planning and implementation of the mock…

  9. Incorporating robotics into secondary education

    Microsoft Academic Search

    Kevin Wedeward; Stephen Bruder

    2002-01-01

    Universities can play an important role in the high school educational system. In particular, New Mexico Tech has developed a robotics outreach program to provide high school students exposure to engineering concepts via building small robots. The authors have developed an integrated approach for incorporating robotics into secondary education with the objective of further engaging students through an exciting application

  10. Effect of nanoparticle size on the internal structure of copolymer-nanoparticles composite thin films studied by neutron reflection

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Kornilov, E. I.; Hamdoun, B.

    1998-04-01

    Neutron reflection was used for the study of the composite films made of symmetric (d-PS-PBMA) diblock copolymer (molecular weight Mw=170 and 135 K) with nanoparticles of ?-Fe2O3 (4 and 6 nm in diameter) incorporated in the deuterated PS-domains with different concentrations. From the neutron reflection experiment we determined the period of the lamellar structure and the position of the nanoparticles in the PS-layers. It is important to examine the effect of the particle size on the lamellar structure. We determined that the small nanoparticles (4 nm) concentrate close to d-PS-PBMA interfaces while larger nanoparticles (6 nm) localize in the center of PS domains. This effect is of considerable interest in the elaboration of new composite materials since it will give a control on the particle distribution inside the host domains.

  11. Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds

    PubMed Central

    Stevenson, Louise M.; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A.; McCauley, Edward; Nisbet, Roger M.

    2013-01-01

    The vast majority of nanotoxicity studies measures the effect of exposure to a toxicant on an organism and ignores the potentially important effects of the organism on the toxicant. We investigated the effect of citrate-coated silver nanoparticles (AgNPs) on populations of the freshwater alga Chlamydomonas reinhardtii at different phases of batch culture growth and show that the AgNPs are most toxic to cultures in the early phases of growth. We offer strong evidence that reduced toxicity occurs because extracellular dissolved organic carbon (DOC) compounds produced by the algal cells themselves mitigate the toxicity of AgNPs. We analyzed this feedback with a dynamic model incorporating algal growth, nanoparticle dissolution, bioaccumulation of silver, DOC production and DOC-mediated inactivation of nanoparticles and ionic silver. Our findings demonstrate how the feedback between aquatic organisms and their environment may impact the toxicity and ecological effects of engineered nanoparticles. PMID:24086348

  12. Nanoparticles for Biomedical Imaging

    SciTech Connect

    Nune, Satish K.; Gunda, Padmaja; Thallapally, Praveen K.; Lin, Ying-Ying; Forrest, Laird M.; Berkland, Cory J.

    2009-11-01

    Background: Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 to 100 nm in diameter possess dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has further expanded the potential of nanoparticles as probes for molecular imaging. Objective: To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced non-specific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods: This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their applications in biomedical imaging. Conclusion: Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. Keywords: nanoparticle synthesis, surface modification, targeting, molecular imaging, and biomedical imaging.

  13. Nanoparticles on Photovoltaic Performance of Fabricated DSSCs

    NASA Astrophysics Data System (ADS)

    Agarwala, Pooja; Makkar, Preeti; Sharma, Sarika; Garg, Rajnish

    2014-10-01

    The present work focuses on the synthesis of mixed phase TiO2 nanoparticles with reduced band gaps without even being doped. The synthesis was carried out by chemical route followed by heat treatments at different temperatures to favor rutile incorporation in anatase network. The significance of different heat treatment temperatures on the phase composition of TiO2 nanoparticles and its effect on optical band gap and the photovoltaic performance are analyzed. The thermal analysis, phases, morphology, and energy band gap of as-synthesized TiO2 nanoparticles have been characterized by DTA/TG, x-ray diffraction, field-emission scanning electron microscope, transmission electron microscope, and UV-Vis-NIR, respectively. The results show the presence of rutile (~15 nm) and anatase phases (~17 nm) in "as-synthesized" TiO2 nanoparticles. TiO2 nanoparticles are heat treated for 2 h at 200, 400, and 600 °C in air. It is observed that heat treatment results in higher photoactivity in visible region of the solar radiation and the material demonstrated high photovoltaic performance in conjunction with N-719. The optical band gap values are found to be in the range of 2.59-2.88 eV. The dye-sensitized solar cells (DSSCs) fabricated by TiO2 nanoparticles, heat treated at 600 ºC show the energy conversion efficiency (?) of 6.08% with high photo current density ( J sc) of 11.76 mA/cm2. The work highlighted in this paper represents the realization of simple method of achieving low band gap semiconductors without being doped, for DSSCs applications.

  14. Inflammatory and genotoxic effects of sanding dust generated from nanoparticle-containing paints and lacquers.

    PubMed

    Saber, Anne Thoustrup; Koponen, Ismo Kalevi; Jensen, Keld Alstrup; Jacobsen, Nicklas Raun; Mikkelsen, Lone; Møller, Peter; Loft, Steffen; Vogel, Ulla; Wallin, Håkan

    2012-11-01

    Nanoparticles are increasingly used in paints and lacquers. Little is known of the toxicity of nanoparticles incorporated in complex matrices and released during different phases of the life cycle. DNA damaging activity and inflammogenicity of sanding dust sampled during standardised sanding of boards painted with paints with and without nanoparticles were determined 24 h after intratracheal instillation of a single dose of 54 ?g in mice. Dusts from nanoparticle-containing paints and lacquers did not generate pulmonary inflammation or oxidative stress. Sanding dust from both the nanoparticle-containing and the conventional lacquer and the outdoor acrylic-based reference paint increased the level of DNA strand breaks in bronchoalveolar fluid cells. In conclusion, addition of nanoparticles to paint or lacquers did not increase the potential of sanding dust for causing inflammation, oxidative stress or DNA damage, suggesting that the paint/lacquer matrix is more important as determinant of DNA damage than the nanomaterial. PMID:21995293

  15. Improving resveratrol bioaccessibility using biopolymer nanoparticles and complexes: impact of protein-carbohydrate maillard conjugation.

    PubMed

    Davidov-Pardo, Gabriel; Pérez-Ciordia, Sonia; Marín-Arroyo, María R; McClements, David Julian

    2015-04-22

    The impact of encapsulating resveratrol in biopolymer nanoparticles or biopolymer complexes on its physicochemical stability and bioaccessibility was determined. The biopolymer nanoparticles consisted of a zein core surrounded by a caseinate or caseinate-dextran shell. The biopolymer complexes consisted of resveratrol bound to caseinate or caseinate-dextran. The caseinate-dextran conjugates were formed using the Maillard reaction. Both the biopolymer nanoparticles and complexes protected trans-resveratrol from isomerization when exposed to UV light, with the nanoparticles being more effective. Nanoparticles coated by caseinate-dextran were more stable to aggregation under simulated gastrointestinal conditions than those coated by caseinate, presumably due to greater steric repulsion. The bioaccessibility of resveratrol was enhanced when it was encapsulated in both biopolymer nanoparticles and biopolymer complexes. These results have important implications for the development of effective delivery systems for incorporating lipophilic nutraceuticals into functional foods and beverages. PMID:25843145

  16. Nanoparticle agglomerates in magnetoliposomes

    NASA Astrophysics Data System (ADS)

    Cintra, E. R.; Ferreira, F. S.; Santos Junior, J. L.; Campello, J. C.; Socolovsky, L. M.; Lima, E. M.; Bakuzis, A. F.

    2009-01-01

    Magnetoliposomes consist of vesicles composed of a phospholipid membrane encapsulating magnetic nanoparticles. These systems have several important applications, such as in MRI contrast agents, drug and gene carriers, and cancer treatment devices. For all of these applications, controlling the number of encapsulated magnetic nanoparticles is a key issue. In this work, we used a magneto-optical technique to obtain information about the efficiency of encapsulation, the number of nanoparticles encapsulated per liposome and also about the formation of the nanoparticle structures. The parameters studied included the effect of the duration of sonication, the presence of cholesterol in the liposome membrane, as well as time-related stability. For the liposomal vesicles prepared in this work, we found between 35 and 300 nanoparticles encapsulated per liposome, depending on the experimental conditions, consisting of small linear chains of nanoparticles, basically trimers and tetramers. The methodology developed might be useful for the investigation and improvement of the properties of several magnetic nanocarrier systems.

  17. Nanoparticle agglomerates in magnetoliposomes.

    PubMed

    Cintra, E R; Ferreira, F S; Santos Junior, J L; Campello, J C; Socolovsky, L M; Lima, E M; Bakuzis, A F

    2009-01-28

    Magnetoliposomes consist of vesicles composed of a phospholipid membrane encapsulating magnetic nanoparticles. These systems have several important applications, such as in MRI contrast agents, drug and gene carriers, and cancer treatment devices. For all of these applications, controlling the number of encapsulated magnetic nanoparticles is a key issue. In this work, we used a magneto-optical technique to obtain information about the efficiency of encapsulation, the number of nanoparticles encapsulated per liposome and also about the formation of the nanoparticle structures. The parameters studied included the effect of the duration of sonication, the presence of cholesterol in the liposome membrane, as well as time-related stability. For the liposomal vesicles prepared in this work, we found between 35 and 300 nanoparticles encapsulated per liposome, depending on the experimental conditions, consisting of small linear chains of nanoparticles, basically trimers and tetramers. The methodology developed might be useful for the investigation and improvement of the properties of several magnetic nanocarrier systems. PMID:19417311

  18. Preparation and in vitro evaluation of mucoadhesion and permeation enhancement of thiolated chitosan-pHEMA core-shell nanoparticles.

    PubMed

    Moghaddam, Firooze Aghaei; Atyabi, Fatemeh; Dinarvand, Rassoul

    2009-06-01

    The aim of the present work was to evaluate the in vitro mucoadhesion and permeation enhancement properties of thiolated chitosan (chitosan-glutathione) coated poly(hydroxyl ethyl methacrylate) nanoparticles. Core-shell nanoparticles were prepared by radical emulsion polymerization method initiated by cerium(IV) ammonium nitrate. Different molecular weights of chitosan were utilized for nanoparticles preparation. The physicochemical properties of nanoparticles were characterized by size, zeta potential, and thiol content. Incorporation of fluorescein isothiocyanate dextran (FD4, MW 4400 Da), which was used as the model macromolecule, was achieved by incubation method. The intestinal mucoadhesion and penetration enhancement properties of nanoparticles were investigated using excised rat jejunum. All nanoparticle systems showed mucoadhesion and improved apparent permeation coefficient (P(app)) of FD4. Nanoparticles prepared by thiolated chitosan with medium molecular weight revealed the most mucoadhesion and penetration enhancement properties. PMID:19186220

  19. Influence of ferrite nanoparticle type and content on the crystallization kinetics and electroactive phase nucleation of poly(vinylidene fluoride).

    PubMed

    Sencadas, Vitor; Martins, Pedro; Pitães, Alexandre; Benelmekki, Maria; Gómez Ribelles, José Luis; Lanceros-Mendez, Senentxu

    2011-06-01

    This work reports on the nucleation of the ?-phase of poly(vinylidene fluoride) (PVDF) by incorporating CoFe(2)O(4) and NiFe(2)O(4) nanoparticles, leading in this way to the preparation of magnetoelectric composites. The fraction of filler nanoparticles needed to produce the same ?- to ?-phase ratio in crystallized PVDF is 1 order of magnitude lower in the cobalt ferrite nanoparticles. The interaction between nanoparticles and PVDF chains induce the all-trans conformation in PVDF segments, and this structure then propagates in crystal growth. The nucleation kinetics is enhanced by the presence of nanoparticles, as corroborated by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami's exponent. Further, the decrease of the crystalline fraction of PVDF with increasing nanoparticle content indicates that an important fraction of polymer chains are confined in interphases with the filler particle. PMID:21545124

  20. Stimulus Responsive Nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2015-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  1. Functional Magnetic Nanoparticles

    Microsoft Academic Search

    James Gass

    2012-01-01

    Nanoparticle system research and characterization is the focal point of this research and dissertation. In the research presented here, magnetite, cobalt, and ferrite nanoparticle systems have been explored in regard to their magnetocaloric effect (MCE) properties, as well as for use in polymer composites. Both areas of study have potential applications across a wide variety of interdisciplinary fields.\\u000aMagnetite nanoparticles

  2. Stimulus responsive nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darren Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2013-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  3. Flexible Workflow Incorporated with RBAC

    Microsoft Academic Search

    Yuqing Sun; Xiangxu Meng; Shijun Liu; Peng Pan

    2005-01-01

    \\u000a In this paper, we propose a new model to incorporate RBAC into a flexible workflow system. Without compromising the flexibility\\u000a of workflow, this model can effectively enhance the security control of the user access to the workflow system. Specifically,\\u000a it provides the corresponding mechanism to maintain the constraint consistency in dynamic management of workflow. We present\\u000a the basic design and

  4. Anti-biofilm properties of wound dressing incorporating nonrelease polycationic antimicrobials.

    PubMed

    Atar-Froyman, Livnat; Sharon, Anat; Weiss, Ervin I; Houri-Haddad, Yael; Kesler-Shvero, Dana; Domb, Abraham J; Pilo, Raphael; Beyth, Nurit

    2015-04-01

    Polycationic nanoparticles show biocompatible, broad-spectrum bactericidal properties in vitro and in vivo when incorporated in denture lining material post-maxillectomy in head and neck cancer patients. In the present study, the synthesized Crosslinked quaternary ammonium polyethylenimine nanoparticles were found to have a strong bactericidal activity against a wide variety of microorganisms rapidly killing bacterial cells when incorporated at small concentrations into soft lining materials without compromising mechanical and biocompatibility properties. This appears advantageous over conventional released antimicrobials with regard to in vivo efficacy and safety, and may provide a convenient platform for the development of non-released antimicrobials. This is a crucial issue when it comes to giving an answer to the serious and life-threatening problems of contaminations in immunocompromised patients such as orofacial cancer patient. PMID:25678123

  5. Effect of nickel incorporation on the optical properties of diamond-like carbon (DLC) matrix

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Hussain, S.

    2011-10-01

    The present study investigates the optical behavior of composite nanostructured DLC based films and functional coatings. Diamond-like carbon (DLC) thin films were synthesized by electrodeposition method onto SnO 2 -coated glass substrates using an electrolyte of a mixture of acetic acid and water. Nanoparticles of nickel were then introduced into the DLC matrix. Morphology of the metal incorporated thin films and distribution of nanoparticles were studied by SEM; continuous homogeneous distribution of the particles was observed. Raman spectroscopy showed additional peaks in addition to the peaks due to DLC matrix. FTIR spectra revealed new peaks in the lower wave number region due to metal inclusion. UV-vis transmittance studies were performed to calculate the band gap of the samples. The estimated band gap from the Tauc relation was found to vary from 2.63 eV for the virgin DLC to 1.48 eV for the metal incorporated DLC.

  6. Nanoparticles for biomedical imaging

    PubMed Central

    Nune, Satish K; Gunda, Padmaja; Thallapally, Praveen K; Lin, Ying-Ying; Forrest, M Laird; Berkland, Cory J

    2011-01-01

    Background Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 – 100 nm in diameter have dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has expanded further the potential of nanoparticles as probes for molecular imaging. Objective To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced nonspecific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their application in biomedical imaging. Conclusion Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. PMID:19743894

  7. Fabrication of three-dimensionally interconnected nanoparticle superlattices and their lithium-ion storage properties

    PubMed Central

    Jiao, Yucong; Han, Dandan; Ding, Yi; Zhang, Xianfeng; Guo, Guannan; Hu, Jianhua; Yang, Dong; Dong, Angang

    2015-01-01

    Three-dimensional superlattices consisting of nanoparticles represent a new class of condensed materials with collective properties arising from coupling interactions between close-packed nanoparticles. Despite recent advances in self-assembly of nanoparticle superlattices, the constituent materials have been limited to those that are attainable as monodisperse nanoparticles. In addition, self-assembled nanoparticle superlattices are generally weakly coupled due to the surface-coating ligands. Here we report the fabrication of three-dimensionally interconnected nanoparticle superlattices with face-centered cubic symmetry without the presynthesis of the constituent nanoparticles. We show that mesoporous carbon frameworks derived from self-assembled supercrystals can be used as a robust matrix for the growth of nanoparticle superlattices with diverse compositions. The resulting interconnected nanoparticle superlattices embedded in a carbon matrix are particularly suitable for energy storage applications. We demonstrate this by incorporating tin oxide nanoparticle superlattices as anode materials for lithium-ion batteries, and the resulting electrochemical performance is attributable to their unique architectures. PMID:25739732

  8. Biofunctionalized prussian blue nanoparticles for multimodal molecular imaging applications.

    PubMed

    Vojtech, Jennifer M; Cano-Mejia, Juliana; Dumont, Matthieu F; Sze, Raymond W; Fernandes, Rohan

    2015-01-01

    Multimodal, molecular imaging allows the visualization of biological processes at cellular, subcellular, and molecular-level resolutions using multiple, complementary imaging techniques. These imaging agents facilitate the real-time assessment of pathways and mechanisms in vivo, which enhance both diagnostic and therapeutic efficacy. This article presents the protocol for the synthesis of biofunctionalized Prussian blue nanoparticles (PB NPs)--a novel class of agents for use in multimodal, molecular imaging applications. The imaging modalities incorporated in the nanoparticles, fluorescence imaging and magnetic resonance imaging (MRI), have complementary features. The PB NPs possess a core-shell design where gadolinium and manganese ions incorporated within the interstitial spaces of the PB lattice generate MRI contrast, both in T1 and T2-weighted sequences. The PB NPs are coated with fluorescent avidin using electrostatic self-assembly, which enables fluorescence imaging. The avidin-coated nanoparticles are modified with biotinylated ligands that confer molecular targeting capabilities to the nanoparticles. The stability and toxicity of the nanoparticles are measured, as well as their MRI relaxivities. The multimodal, molecular imaging capabilities of these biofunctionalized PB NPs are then demonstrated by using them for fluorescence imaging and molecular MRI in vitro. PMID:25993028

  9. OPTICAL PROPERTIES OFOPTICAL PROPERTIES OF METALLIC NANOPARTICLES,METALLIC NANOPARTICLES,

    E-print Network

    Grujicic, Mica

    OPTICAL PROPERTIES OFOPTICAL PROPERTIES OF METALLIC NANOPARTICLES,METALLIC NANOPARTICLES, MOLECULESImaginary Part of Dielectric Function of Particles ppp i += Dielectric Function of the NanoparticlesDielectric Function of the Nanoparticles #12;Complex Dielectric FunctionComplex Dielectric Function For Bulk Material

  10. Covalently functionalized gold nanoparticles: Synthesis, characterization, and integration into capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Ivanov, Michael Robert

    Nanomaterials are widely used as pseudostationary and stationary phases in electrically driven separations. The advantages of using nanomaterials are numerous including tunable sizes, multiple core compositions, flexible injection schemes, and diverse surface chemistries. Nanomaterials, however, exhibit large surface energies which induce aggregation and may yield unpredictable function in separations. Because nanomaterials can modify buffer conductivity, viscosity, and pH; successful and systematic incorporation of nanomaterials into separations requires rigorous synthetic control and characterization of both the nanoparticle core and surface chemistry. This dissertation investigates the impact of gold nanoparticle surface chemistry and morphology to capillary electrophoresis separations. Gold nanoparticle core composition, shape, size, self assembled monolayer (SAM) formation, and SAM packing density are quantified for gold nanoparticles functionalized with thioctic acid, 6-mercaptohexanoic acid, or 11-mercaptoundecanoic acid SAMs. TEM, 1H NMR, extinction spectroscopy, zeta potential, X-ray photoelectron spectroscopy, and flocculation assess the morphology, surface chemistry, optical properties, surface charge, SAM packing density, and stability of the nanoparticles, respectively. Using well-characterized nanostructures, pseudostationary phases of gold nanoparticles in capillary electrophoresis are studied. Gold nanoparticles functionalized with thioctic acid and either 6-mercaptohexanoic acid or 6-aminohexanethiol impact the mobility of analytes in a concentration and surface chemistry-dependent manner. From these data, a novel parameter termed the critical nanoparticle concentration is developed and is used to estimate nanoparticle stability during capillary electrophoresis separations. To understand the function of carboxylated gold nanoparticles in capillary electrophoresis, extended DLVO theory is used to model interparticle interactions. Nanoparticle aggregation leads to electron tunneling between nanoparticles thereby taking on bulk electrical properties which cause measured currents to increase for nanoparticles functionalized with poorly ordered SAMs. Nanoparticles functionalized with well-ordered SAMs main their nanoscale properties and reduce measured currents during electrically driven flow. Finally, carboxylic acid functionalized gold nanoparticles effect the separation of target biomarkers in both a SAM composition and surface coverage dependent manner. These effects are most systematic with well ordered SAMs. To understand the separation mechanism functionalized gold nanoparticles exhibit, their ? potential with and without dopamine are evaluated. Large dopamine concentrations neutralize the three functionalized gold nanoparticles according to a dose response curve. The positively charged dopamine molecules saturate the negatively charged nanoparticle surfaces thereby providing a plausible explanation to the observed biomarker concentration trends. These data and future work provide a rigorous experimental and theoretical evaluation of nanoparticle structure impacts their function as pseudostationary phases in separations and other applications.

  11. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  12. Acylated kaempferol diglycoside from Allium senescens

    Microsoft Academic Search

    I. Yu. Selyutina; L. M. Tankhaeva; D. N. Olennikov

    2008-01-01

    Allium senescens L. s. str. (Liliaceae) is a medicinal plant used in Tibetan medicine for treating diseases of the hematopoietic system [1]. The chemical composition of this species has been insufficiently studied. It is known to contain ascorbic acid [2], the alkaloid alliin [3], and two spirostanol glycosides gracillin and rhamnosidodioscin [4]. The goal of our work was to investigate

  13. Nanoparticles for bioimaging

    Microsoft Academic Search

    Parvesh Sharma; Scott Brown; Glenn Walter; Swadeshmukul Santra; Brij Moudgil

    2006-01-01

    The emergence of synthesis strategies for the fabrication of nanosized contrast agents is anticipated to lead to advancements in understanding biological processes at the molecular level in addition to progress in the development of diagnostic tools and innovative therapies. Imaging agents such as fluorescent dye-doped silica nanoparticles, quantum dots and gold nanoparticles have overcome many of the limitations of conventional

  14. Nanoparticles in Ophthalmic Medicine

    Microsoft Academic Search

    Yureeda Qazi; Brian Stagg; Balamurali Ambati

    2009-01-01

    Over the past decade, nanoparticles have risen to the forefront of biotechnology, promising diverse applications in the fields of gene therapy, drug delivery, and imaging. Nanoparticles can be engineered to create optimal features that are tissue-specific or target-orientated to promote their uptake, clearance, biodegradability, reduced immunogenicity, and detection. Nanomedicine offers potentially safe and successful treatment regimens for ocular disorders. In

  15. Stability and Aggregation of Metal Oxide Nanoparticles in Natural

    E-print Network

    Cardinale, Bradley J.

    O) nanoparticles, such as TiO2, ZnO and CeO2, are increasingly incorporated into a wide range of products (e.gStability and Aggregation of Metal Oxide Nanoparticles in Natural Aqueous Matrices A R T U R O A . K E L L E R , H O N G T A O W A N G , , D O N G X U Z H O U , H U N T E R S . L E N I H A N , G

  16. Targeting nanoparticles to cancer.

    PubMed

    Wang, M; Thanou, M

    2010-08-01

    Nanotechnology applications in medicine, termed as nanomedicine, have introduced a number of nanoparticles of variable chemistry and architecture for cancer imaging and treatment. Nanotechnology involves engineering multifunctional devices with dimensions at the nanoscale, similar dimensions as those of large biological vesicles or molecules in our body. These devices typically have features just tens to hundred nanometers across and they can carry one or two detection signals and/or therapeutic cargo(s). One unique class of nanoparticles is designed to do both, providing this way the theragnostic nanoparticles (therapy and diagnosis). Being inspired by physiologically existing nanomachines, nanoparticles are designed to safely reach their target and specifically release their cargo at the site of the disease, this way increasing the drug's tissue bioavailability. Nanoparticles have the advantage of targeting cancer by simply being accumulated and entrapped in tumours (passive targeting). The phenomenon is called the enhanced permeation and retention effect, caused by leaky angiogenetic vessels and poor lymphatic drainage and has been used to explain why macromolecules and nanoparticles are found at higher ratios in tumours compared to normal tissues. Although accumulation in tumours is observed cell uptake and intracellular drug release have been questioned. Polyethyleneglycol (PEG) is used to protect the nanoparticles from the Reticulo-Endothelial System (RES), however, it prevents cell uptake and the required intracellular drug release. Grafting biorecognition molecules (ligands) onto the nanoparticles refers to active targeting and aims to increase specific cell uptake. Nanoparticles bearing these ligands are recognised by cell surface receptors and this leads to receptor-mediated endocytosis. Several materials are suggested for the design of nanoparticles for cancer. Polymers, linear and dendrimers, are associated with the drug in a covalent or non-covalent way and have been used with or without a targeting ligand. Stealth liposomes are suggested to carry the drug in the aqueous core, and they are usually decorated by recognition molecules, being widely studied and applied. Inorganic nanoparticles such as gold and iron oxide are usually coupled to the drug, PEG and the targeting ligand. It appears that the PEG coating and ligand decoration are common constituents in most types of nanoparticles for cancer. There are several examples of successful cancer diagnostic and therapeutic nanoparticles and many of them have rapidly moved to clinical trials. Nevertheless there is still a room for optimisation in the area of the nanoparticle kinetics such as improving their plasma circulation and tumour bioavailability and understanding the effect of targeting ligands on their efficiency to treat cancer. The need to develop novel and efficient ligands has never been greater, and the use of proper conjugation chemistry is mandatory. PMID:20380880

  17. Targeting intracellular compartments by magnetic polymeric nanoparticles.

    PubMed

    Kocbek, Petra; Kralj, Slavko; Kreft, Mateja Erdani; Kristl, Julijana

    2013-09-27

    Superparamagnetic iron oxide nanoparticles (SPIONs) show a great promise for a wide specter of bioapplications, due to their characteristic magnetic properties exhibited only in the presence of magnetic field. Their advantages in the fields of magnetic drug targeting and imaging are well established and their safety is assumed, since iron oxide nanoparticles have already been approved for in vivo application, however, according to many literature reports the bare metal oxide nanoparticles may cause toxic effects on treated cells. Therefore, it is reasonable to prevent the direct interactions between metal oxide core and surrounding environment. In the current research ricinoleic acid coated maghemite nanoparticles were successfully synthesized, characterized and incorporated in the polymeric matrix, resulting in nanosized magnetic polymeric particles. The carrier system was shown to exhibit superparamagnetic properties and was therefore responsive towards external magnetic field. Bioevaluation using T47-D breast cancer cells confirmed internalization of magnetic polymeric nanoparticles (MNPs) and their intracellular localization in various subcellular compartments, depending on presence/absence of external magnetic field. However, the number of internalized MNPs observed by fluorescent and transmission electron microscopy was relatively low, making such way of targeting effective only for delivery of highly potent drugs. The scanning electron microscopy of treated cells revealed that MNPs influenced the cell adhesion, when external magnetic field was applied, and that treatment resulted in damaged apical plasma membrane right after exposure to the magnetic carrier. On the other hand, MNPs showed only reversibly reduced cellular metabolic activity in concentrations up to 200 ?g/ml and, in the tested concentration the cell cycle distribution was within the normal range, indicating safety of the established magnetic carrier system for the treated cells. PMID:23603023

  18. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells

    NASA Astrophysics Data System (ADS)

    Freitas, Jilian N.; Gonçalves, Agnaldo S.; Nogueira, Ana F.

    2014-05-01

    In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed.

  19. Ultrasmall lanthanide-doped nanoparticles as multimodal platforms

    NASA Astrophysics Data System (ADS)

    Yust, Brian G.; Pedraza, Francisco J.; Sardar, Dhiraj K.

    2014-03-01

    Recently, there has been a great amount of interest in nanoparticles which are able to provide a platform with high contrast for multiple imaging modalities in order to advance the tools available to biomedical researchers and physicians. However, many nanoparticles do not have ideal properties to provide high contrast in different imaging modes. In order to address this, ultrasmall lanthanide doped oxide and fluoride nanoparticles with strong NIR to NIR upconversion fluorescence and a strong magnetic response for magnetic resonance imaging (MRI) have been developed. Specifically, these nanoparticles incorporate gadolinium, dysprosium, or a combination of both into the nano-crystalline host to achieve the magnetic properties. Thulium, erbium, and neodymium codopants provide the strong NIR absorption and emission lines that allow for deeper tissue imaging since near infrared light is not strongly absorbed or scattered by most tissues within this region. This also leads to better image quality and lower necessary excitation intensities. As a part of the one pot synthesis, these nanoparticles are coated with peg, pmao, or d-glucuronic acid to make them water soluble, biocompatible, and bioconjugable due to the available carboxyl or amine groups. Here, the synthesis, morphological characterization, magnetic response, NIR emission, and the quantum yield will be discussed. Cytotoxicity tested through cell viability at varying concentrations of nanoparticles in growth media will also be discussed.

  20. Active curcumin nanoparticles formed from a volatile microemulsion template.

    PubMed

    Margulis, K; Srinivasan, S; Ware, M J; Summers, H D; Godin, B; Magdassi, S

    2014-01-01

    We report on biological performance of organic nanoparticles formed by a simple method based on rapid solvent removal from a volatile microemulsion. The particular focus of the study was on testing the suitability of the method for substances soluble in partially water-miscible organic solvents as well as on evaluating the therapeutic activity of the resultant nanoparticles. Curcumin was employed as a model for hydrophobic drug, and, as it is soluble in water-miscible organic solvents, it was successfully incorporated into a new cyclopentanone-water microemulsion system. During rapid solvent removal by spray-drying, the nanometric droplets of the microemulsion were converted into nanoparticles containing amorphous curcumin with the average size of 20.2±3.4 nm, having ? potential of -36.2 ±1.8 mV. These nanoparticles were dispersible in water and retained the high loading of the active substance. The therapeutic activity of the resulting nanoparticles was demonstrated in a pancreatic cancer cell line Panc-1. The effective concentration for reducing the metabolic activity was found to be 11.5 ?M for nanoparticles compared with 19.5 ?M for free curcumin. PMID:25485110

  1. HDL-mimetic PLGA nanoparticle to target atherosclerosis plaque macrophages.

    PubMed

    Sanchez-Gaytan, Brenda L; Fay, Francois; Lobatto, Mark E; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E M; van Rijs, Sarian M; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J; Langer, Robert; Fayad, Zahi A; Mulder, Willem J M

    2015-03-18

    High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA-HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA-HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers. PMID:25650634

  2. Applications and toxicity of silver nanoparticles: a recent review.

    PubMed

    Marin, Stefania; Vlasceanu, George Mihail; Tiplea, Roxana Elena; Bucur, Ioana Raluca; Lemnaru, Madalina; Marin, Maria Minodora; Grumezescu, Alexandru Mihai

    2015-05-27

    Silver nanoparticles (AgNPs) exhibit a consistent amount of flexible properties which endorse them for a larger spectrum of applications in biomedicine and related fields. Over the years, silver nanoparticles have been subjected to numerous in vitro and in vivo tests to provide information about their toxic behavior towards living tissues and organisms. Researchers showed that AgNPs have high antimicrobial efficacy against many bacteria species including Escherichia coli, Neisseria gonorrhea, Chlamydia trachomatis and also viruses. Due to their novel properties, the incorporation of silver nanoparticles into different materials like textile fibers and wound dressings can extend their utility on the biomedical field while inhibiting infections and biofilm development. Among the noble metal nanoparticles, AgNPs present a series of features like simple synthesis routes, adequate and tunable morphology, and high surface to volume ratio, intracellular delivery system, a large plasmon field area recommending them as ideal biosensors, catalysts or photo-controlled delivery systems. In bioengineering, silver nanoparticles are considered potentially ideal gene delivery systems for tissue regeneration. The remote triggered detection and release of bioactive compounds of silver nanoparticles has proved their relevance also in forensic sciences. The authors report an up to date review related to the toxicity of AgNPs and their applications in antimicrobial activity and biosensors for gene therapy. PMID:25877089

  3. Glyconanobiotics: Novel carbohydrated nanoparticle antibiotics for MRSA and Bacillus anthracis

    PubMed Central

    Abeylath, Sampath C.; Turos, Edward; Dickey, Sonja; Limb, Daniel V.

    2008-01-01

    This report describes the synthesis and evaluation of glycosylated polyacrylate nanoparticles that have covalently-bound antibiotics within their framework. The requisite glycosylated drug monomers were prepared from one of three known antibiotics, an N-sec-butylthio ?-lactam, ciprofloxacin, and a penicillin, by acylation with 3-O-acryloyl-1,2-O-isopropylidene-5,6 bis((chlorosuccinyl)oxy)-D-glucofuranose (7) or 6-O-acetyl-3-O-acryloyl-1,2-O-isopropylidene-5-(chlorosuccinyl)oxy-?-D-glucofuranose (10). These acrylated monomers were subjected to emulsion polymerization in a 7:3 (w:w) mixture of butyl acrylate-styrene in the presence of sodium dodecyl sulfate as surfactant (3 weight %) and potassium persulfate as a radical initiator (1 weight %). The resulting nanoparticle emulsions were characterized by dynamic light scattering and found to have similar diameters (~40 nm) and size distributions to those of our previously studied systems. Microbiological testing showed that the N-sec-butylthio ?-lactam and ciprofloxacin nanoparticles both have powerful in vitro activities against methicillin-resistant Staphylococcus aureus and Bacillus anthracis, while the penicillin-bound nanoparticles have no antimicrobial activity. This indicates the need for matching a suitable antibiotic with the nanoparticle carrier. Overall, the study shows that even relatively large, polar acrylate monomers (MW>1000 amu) can be efficiently incorporated into the nanoparticle matrix by emulsion polymerization, providing opportunities for further advances in nanomedicine. PMID:18063370

  4. No evidence for cerium dioxide nanoparticle translocation in maize plants.

    PubMed

    Birbaum, Karin; Brogioli, Robert; Schellenberg, Maya; Martinoia, Enrico; Stark, Wendelin J; Günther, Detlef; Limbach, Ludwig K

    2010-11-15

    The rapidly increasing production of engineered nanoparticles has raised questions regarding their environmental impact and their mobility to overcome biological important barriers. Nanoparticles were found to cross different mammalian barriers, which is summarized under the term translocation. The present work investigates the uptake and translocation of cerium dioxide nanoparticles into maize plants as one of the major agricultural crops. Nanoparticles were exposed either as aerosol or as suspension. Our study demonstrates that 50 ?g of cerium/g of leaves was either adsorbed or incorporated into maize leaves. This amount could not be removed by a washing step and did not depend on closed or open stomata investigated under dark and light exposure conditions. However, no translocation into newly grown leaves was found when cultivating the maize plants after airborne particle exposure. The use of inductively coupled mass spectrometer allowed detection limits of less than 1 ng of cerium/g of leaf. Exposure of plants to well-characterized nanoparticle suspensions in the irrigation water resulted also in no detectable translocation. These findings may indicate that the biological barriers of plants are more resistant against nanoparticle translocation than mammalian barriers. PMID:20964359

  5. Targeted Nanoparticles Assembled via Complexation of Boronic Acid-Containing Targeting Moieties to Diol-Containing Polymers

    PubMed Central

    Han, Han; Davis, Mark E.

    2013-01-01

    The delivery of therapeutics via nanoscaled vehicles for solid cancer treatment can be enhanced by the incorporation of a targeting capability. Here, we describe a new method for assembling a targeted nanoparticle that utilizes the reversible covalent complexation between boronic acids and diols to achieve a targeted nanoparticle for the delivery of anti-cancer drug, camptothecin (CPT). CPT is conjugated to a biocompatible, hydrophilic copolymer of mucic acid and PEG (MAP). When this polymer-drug conjugate is placed in water, it self-assembles into MAP-CPT nanoparticles of ca. 30 nm (diameter) and slightly negative zeta potential. The antibody Herceptin is attached to a boronic acid via a polyethylene glycol (PEG) spacer, and this boronic acid-containing targeting moiety is complexed with the diol-containing MAP to form a targeted MAP-CPT nanoparticle. The addition of Herceptin targeting agent to the MAP-CPT nanoparticles yields targeted MAP-CPT nanoparticles with increased nanoparticle size to ca. 40 nm (diameter). The main mechanisms of CPT release from MAP-CPT nanoparticles are found by in vitro analysis to be hydrolysis and nanoparticle disruption by fat. Cellular uptake of nanoparticles is enhanced by 70% compared to non-targeted version by the incorporation of a single Herceptin antibody targeting agent per nanoparticle. This single Herceptin antibody targeted MAP-CPT nanoparticle system carries ca. 60 CPT molecules per nanoparticle and shows prolonged plasma circulation with an elimination half-life of 21.2 h and AUC value of 2766 ?g.h/ml at a 10 mg CPT/kg tail vein injection in mice. PMID:23461746

  6. Shaped gold and silver nanoparticles

    Microsoft Academic Search

    Yugang Sun; Changhua An

    2011-01-01

    Advance in the synthesis of shaped nanoparticles made of gold and silver is reviewed in this article. This review starts with\\u000a a new angle by analyzing the relationship between the geometrical symmetry of a nanoparticle shape and its internal crystalline\\u000a structures. According to the relationship, the nanoparticles with well-defined shapes are classified into three categories:\\u000a nanoparticles with single crystallinity, nanoparticles

  7. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in cosmetic and dermatological preparations

    Microsoft Academic Search

    R. H. Müller; M. Radtke; S. A. Wissing

    2002-01-01

    Solid lipid nanoparticles (SLN) were developed at the beginning of the 1990s as an alternative carrier system to emulsions, liposomes and polymeric nanoparticles. The paper reviews advantages—also potential limitations—of SLN for the use in topical cosmetic and pharmaceutical formulations. Features discussed include stabilisation of incorporated compounds, controlled release, occlusivity, film formation on skin including in vivo effects on the skin.

  8. Modeling of Au Nanoparticles and Semiconductor Nanowires for Nanodevice Applications

    NASA Astrophysics Data System (ADS)

    Makepeace, A.; Yarrison-Rice, J. M.; Kumar, P.; Fickenscher, M.; Smith, L. M.; Jackson, H. E.; Choi, Y.-J.; Park, G.-J.; Jagadish, C.

    2013-03-01

    Semiconductor nanowires with and without plasmon enhancement are being studied for nanodevice applications ranging from chemical sensors to medical monitors and photovoltaics. Semiconductor nanowires can incorporate materials with different bandgaps and can be p- or n-doped. Growths come in different morphologies and geometries (bare, axial or radial heterostructures); all of which expands the design parameters for photocurrent based devices. When Au nanoparticles are attached to nanowires, the local electric field can be enhanced by orders of magnitude, thus increasing their absorption and photocurrent. Using an FDTD Maxwell solver, we simulate local electric fields and absorption characteristics of semiconductor nanowires and Au nanoparticles. We report on spherical, cylindrical and bipyramidal Au nanoparticles with local electric field enhancements that increase with nanoparticle asymmetry and sharp features. The Au nanoparticle modeling data is also in good agreement with experimental absorption data. Initial investigations of 275 nm InP nanowires exhibit internal mode structure under illumination with both polarizations, and absorption coefficients as a function of wavelength. These results provide insight into our experimental investigations of nanowire device applications. Semiconductor nanowires with and without plasmon enhancement are being studied for nanodevice applications ranging from chemical sensors to medical monitors and photovoltaics. Semiconductor nanowires can incorporate materials with different bandgaps and can be p- or n-doped. Growths come in different morphologies and geometries (bare, axial or radial heterostructures); all of which expands the design parameters for photocurrent based devices. When Au nanoparticles are attached to nanowires, the local electric field can be enhanced by orders of magnitude, thus increasing their absorption and photocurrent. Using an FDTD Maxwell solver, we simulate local electric fields and absorption characteristics of semiconductor nanowires and Au nanoparticles. We report on spherical, cylindrical and bipyramidal Au nanoparticles with local electric field enhancements that increase with nanoparticle asymmetry and sharp features. The Au nanoparticle modeling data is also in good agreement with experimental absorption data. Initial investigations of 275 nm InP nanowires exhibit internal mode structure under illumination with both polarizations, and absorption coefficients as a function of wavelength. These results provide insight into our experimental investigations of nanowire device applications. Financial support through NSF DMR grants 0806572 and 1105121.

  9. Novel ionically crosslinked casein nanoparticles for flutamide delivery: formulation, characterization, and in vivo pharmacokinetics

    PubMed Central

    Elzoghby, Ahmed O; Helmy, Maged W; Samy, Wael M; Elgindy, Nazik A

    2013-01-01

    A novel particulate delivery matrix based on ionically crosslinked casein (CAS) nanoparticles was developed for controlled release of the poorly soluble anticancer drug flutamide (FLT). Nanoparticles were fabricated via oil-in-water emulsification then stabilized by ionic crosslinking of the positively charged CAS molecules below their isoelectric point, with the polyanionic crosslinker sodium tripolyphosphate. With the optimal preparation conditions, the drug loading and incorporation efficiency achieved were 8.73% and 64.55%, respectively. The nanoparticles exhibited a spherical shape with a size below 100 nm and a positive zeta potential (+7.54 to +17.3 mV). FLT was molecularly dispersed inside the nanoparticle protein matrix, as revealed by thermal analysis. The biodegradability of CAS nanoparticles in trypsin solution could be easily modulated by varying the sodium tripolyphosphate crosslinking density. A sustained release of FLT from CAS nanoparticles for up to 4 days was observed, depending on the crosslinking density. After intravenous administration of FLT-CAS nanoparticles into rats, CAS nanoparticles exhibited a longer circulation time and a markedly delayed blood clearance of FLT, with the half-life of FLT extended from 0.88 hours to 14.64 hours, compared with drug cosolvent. The results offer a promising method for tailoring biodegradable, drug-loaded CAS nanoparticles as controlled, long-circulating drug delivery systems of hydrophobic anticancer drugs in aqueous vehicles. PMID:23658490

  10. Ordered nanoparticle arrays interconnected by molecular linkers: electronic and optoelectronic properties.

    PubMed

    Liao, Jianhui; Blok, Sander; van der Molen, Sense Jan; Diefenbach, Sandra; Holleitner, Alexander W; Schönenberger, Christian; Vladyka, Anton; Calame, Michel

    2015-02-21

    Arrays of metal nanoparticles in an organic matrix have attracted a lot of interest due to their diverse electronic and optoelectronic properties. Recent work demonstrates that nanoparticle arrays can be utilized as a template structure to incorporate single molecules. In this arrangement, the nanoparticles act as electronic contacts to the molecules. By varying parameters such as the nanoparticle material, the matrix material, the nanoparticle size, and the interparticle distance, the electronic behavior of the nanoparticle arrays can be substantially tuned and controlled. Furthermore, via the excitation of surface plasmon polaritons, the nanoparticles can be optically excited and electronically read-out. The versatility and possible applications of well-ordered nanoparticle arrays has been demonstrated by the realization of switching devices triggered optically or chemically and by the demonstration of chemical and mechanical sensing. Interestingly, hexagonal nanoparticle arrays may also become a useful platform to study the physics of collective plasmon resonances that can be described as Dirac-like bosonic excitations. PMID:25367894

  11. Effect of Gold Nanoparticle on Structure and Fluidity of Lipid Membrane

    PubMed Central

    Mhashal, Anil R.; Roy, Sudip

    2014-01-01

    This paper deals with the effect of different size gold nanoparticles on the fluidity of lipid membrane at different regions of the bilayer. To investigate this, we have considered significantly large bilayer leaflets and incorporated only one nanoparticle each time, which was subjected to all atomistic molecular dynamics simulations. We have observed that, lipid molecules located near to the gold nanoparticle interact directly with it, which results in deformation of lipid structure and slower dynamics of lipid molecules. However, lipid molecules far away from the interaction site of the nanoparticle get perturbed, which gives rise to increase in local ordering of the lipid domains and decrease in fluidity. The bilayer thickness and area per head group in this region also get altered. Similar trend, but with different magnitude is also observed when different size nanoparticle interact with the bilayer. PMID:25469786

  12. Nanoparticle-Based Systems for T1-Weighted Magnetic Resonance Imaging Contrast Agents

    PubMed Central

    Zhu, Derong; Liu, Fuyao; Ma, Lina; Liu, Dianjun; Wang, Zhenxin

    2013-01-01

    Because magnetic resonance imaging (MRI) contrast agents play a vital role in diagnosing diseases, demand for new MRI contrast agents, with an enhanced sensitivity and advanced functionalities, is very high. During the past decade, various inorganic nanoparticles have been used as MRI contrast agents due to their unique properties, such as large surface area, easy surface functionalization, excellent contrasting effect, and other size-dependent properties. This review provides an overview of recent progress in the development of nanoparticle-based T1-weighted MRI contrast agents. The chemical synthesis of the nanoparticle-based contrast agents and their potential applications were discussed and summarized. In addition, the recent development in nanoparticle-based multimodal contrast agents including T1-weighted MRI/computed X-ray tomography (CT) and T1-weighted MRI/optical were also described, since nanoparticles may curtail the shortcomings of single mode contrast agents in diagnostic and clinical settings by synergistically incorporating functionality. PMID:23698781

  13. Interactions and magnetic relaxation in boron doped Mn3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Laha, S. S.; Mukherjee, R.; Lawes, G.

    2014-04-01

    We have studied magnetic interactions in phase pure Mn3O4 and composite Mn2O3/Mn3O4 nanoparticle systems having different interparticle separations between the Mn3O4 ferrimagnetic cores. We characterized the morphology and structure of these nanoparticles using x-ray diffraction and transmission electron microscopy. We find that the incorporation of boron stabilizes the Mn3O4 spinel structure resulting in the formation of phase pure nanoparticles, while in the absence of boron, the sample consists of both Mn3O4 and antiferromagnetic Mn2O3 nanoparticles. We correlate the morphology of these systems with their magnetic properties using ac susceptibility studies. The low temperature frequency dependent relaxation exhibits larger magnetic interactions in the phase pure Mn3O4 nanoparticles as compared to the Mn3O4/Mn2O3 composites, which we attribute to differences in the separation between the ferrimagnetic cores in these two samples.

  14. Active targeting of cancer cells using folic acid-conjugated platinum nanoparticles

    NASA Astrophysics Data System (ADS)

    Teow, Yiwei; Valiyaveettil, Suresh

    2010-12-01

    Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Water soluble platinum nanoparticles were synthesized via reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. The bioactivity of folic acid and poly(vinyl pyrrolidone) capped platinum nanoparticles (Pt-nps) has been investigated using commercially available cell lines. In the cell viability experiments, PVP-capped nanoparticles were found to be less toxic (>80% viability), whereas, folic acid-capped platinum nanoparticles showed a reduced viability down to 24% after 72 h of exposure at a concentration of 100 ?g ml-1 for MCF7 breast cancer cells. Such toxicity, combined with the possibility to incorporate functional organic molecules as capping agents, can be used for developing new drug candidates.

  15. Stem Cells: Physical Stimuli-Induced Chondrogenic Differentiation of Mesenchymal Stem Cells Using Magnetic Nanoparticles (Adv. Healthcare Mater. 9/2015).

    PubMed

    Son, Boram; Kim, Hwan D; Kim, Minsoo; Kim, Jeong Ah; Lee, Jinkyu; Shin, Heungsoo; Hwang, Nathaniel S; Park, Tai Hyun

    2015-06-01

    On page 1339, N. S. Hwang, T. H. Park, and co-workers induce chondrogenic differentiation of mesenchymal stem cells by physical stimulation using magnetic nanoparticles. Magnetic nanoparticles isolated from magnetic bacteria are introduced into the mesenchymal stem cells. Then, the magnetic particle-incorporated mesenchymal stem cells are subjected to static magnetic field and/or magnet-derived shear stress. This magnetic nanoparticle-mediated physical stimulation can be used for cartilage tissue engineering. PMID:26109038

  16. Intracellular imaging of HeLa cells by non-functionalized NaYF4 : Er3+, Yb3+ upconverting nanoparticles

    Microsoft Academic Search

    Fiorenzo Vetrone; Rafik Naccache; Angeles Juarranz de La Fuente; Francisco Sanz-Rodríguez; Alfonso Blazquez-Castro; Emma Martin Rodriguez; Daniel Jaque; José García Solé; John A. Capobianco

    2010-01-01

    We report on the efficient incorporation of non-functionalized NaYF4 : Er3+, Yb3+ nanoparticles inside HeLa live cancer cells by direct endocytosis. The efficient two-photon excited near-infrared-to-visible upconversion fluorescence of these nanoparticles is then used to obtain high-contrast intracellular fluorescence images of single cells. These images reveal a redistribution of the nanoparticles inside the cell as the incubation time increases. Thus,

  17. Gas Phase Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Granqvist, Claes; Kish, Laszlo; Marlow, William

    This book deals with gas-phase nanoparticle synthesis and is intended for researchers and research students in nanomaterials science and engineering, condensed matter physics and chemistry, and aerosol science. Gas-phase nanoparticle synthesis is instrumental to nanotechnology - a field in current focus that raises hopes for environmentally benign, resource-lean manufacturing. Nanoparticles can be produced by many physical, chemical, and even biological routes. Gas-phase synthesis is particularly interesting since one can achieve accurate manufacturing control and hence industrial viability.

  18. Nanoparticle Stained Glass

    NSDL National Science Digital Library

    2014-06-18

    In this activity/demo, learners are introduced to the connection between medieval stained glass artisans and nanotechnology. Learners discover that the red and yellow colors in stained glass windows come from nanoparticles of gold and silver embedded in the glass. This activity/demo consists of two hands-on activities: making a collaborative stained glass window with pre-made nanoparticle solutions containing silver or gold and making a take-away card that contains a small piece of nanoparticle stained “glass."

  19. Synthesis of Silver Nanoparticles

    NSDL National Science Digital Library

    Johnson, Chris

    This series of videos, presented by the Materials Research Science and Engineering Center at the University of Wisconsin-Madison, deals with the synthesis of silver nanoparticles. The experiment allows students to view the formation of silver nanoparticles that can be detected by the reflection of a laser beam. Silver nanoparticles are used in the creation of yellow stained glass in churches around the country, an interesting, but little known fact. This is a fairly inexpensive activity as it involves stock solutions, and equipment present in any science laboratory. Overall, students will enjoy this basic, but still challenging, experiment.

  20. Crystallization of DNA-capped gold nanoparticles in high-concentration, divalent salt environments.

    PubMed

    Tan, Shawn J; Kahn, Jason S; Derrien, Thomas L; Campolongo, Michael J; Zhao, Mervin; Smilgies, Detlef-M; Luo, Dan

    2014-01-27

    The multiparametric nature of nanoparticle self-assembly makes it challenging to circumvent the instabilities that lead to aggregation and achieve crystallization under extreme conditions. By using non-base-pairing DNA as a model ligand instead of the typical base-pairing design for programmability, long-range 2D DNA-gold nanoparticle crystals can be obtained at extremely high salt concentrations and in a divalent salt environment. The interparticle spacings in these 2D nanoparticle crystals can be engineered and further tuned based on an empirical model incorporating the parameters of ligand length and ionic strength. PMID:24459055

  1. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks

    PubMed Central

    2014-01-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 ? /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. PMID:24666992

  2. New strategies for luminescence thermometry in the biological range using upconverting nanoparticles

    NASA Astrophysics Data System (ADS)

    Savchuk, Ol. A.; Carvajal, J. J.; Pujol, M. C.; Massons, J.; Haro-González, P.; Jaque, D.; Aguiló, M.; Díaz, F.

    2014-05-01

    We have studied different strategies of use of luminescence thermometry with upconverting nanoparticles in the biological range of temperatures, among them, the thermal sensing ability of fluoresncent lifetime of Er,Yb:NaY2F5 nanoparticles. Er,Yb:NaY2F5O nanocrystals show great potentiality as thermal sensors at the nanoscale for biomedical applications due to the incorporation of additional non-radiative relaxation mechanisms that shorten the emission lifetime generated by the oxygen present in the structure. Here we report ex-vivo temperature determination by laser induced heating in chicken breast using lifetime-based thermometry in these up-conversion nanoparticles.

  3. Self-assembled nanoparticles of hydrophobically-modified polysaccharide bearing vitamin H as a targeted anti-cancer drug delivery system

    Microsoft Academic Search

    Kun Na; Tae Bum Lee; Keun-Hong Park; Eun-Kyung Shin; Yong-Bok Lee; Hoo-Kyun Choi

    2003-01-01

    Vitamin H (biotin) was incorporated into a hydrophobically modified polysaccharide, pullulan acetate (PA), in order to improve the cancer-targeting activity and internalization of self-assembled nanoparticles. The biotinylated pullulan acetate (BPA) nanoparticles were prepared by a diafiltration method and the mean diameter was approximately 100 nm. Three samples of biotinylated pullulan acetate (BPA), comprising 7 (BPA 1), 20 (BPA 2), and

  4. Covalent incorporation of aminated nanodiamond into an epoxy polymer network.

    PubMed

    Mochalin, Vadym N; Neitzel, Ioannis; Etzold, Bastian J M; Peterson, Amy; Palmese, Giuseppe; Gogotsi, Yury

    2011-09-27

    Outstanding mechanical and optical properties of diamond nanoparticles in combination with their biocompatibility have recently attracted much attention. Modification of the surface chemistry and incorporation into a polymer is required in many applications of the nanodiamond. Nanodiamond powder with reactive amino groups (?20% of the number of surface carbon atoms in each 5 nm particle) was produced in this work by covalent linking of ethylenediamine to the surface carboxyl groups via amide bonds. The synthesized material was reacted with epoxy resin, yielding a composite, in which nanodiamond particles are covalently incorporated into the polymer matrix. The effect of amino groups grafted on the nanodiamond on the curing chemistry of the epoxy resin was analyzed and taken into consideration. Covalently bonded nanodiamond-epoxy composites showed a three times higher hardness, 50% higher Young's modulus, and two times lower creep compared to the composites in which the nanodiamond was not chemically linked to the matrix. Aminated nanodiamond produced and characterized in the present study may also find applications beyond the composites, for example, as a drug, protein, and gene delivery platform in biology and medicine, as a solid support in chromatography and separation science, and in solid state peptide synthesis. PMID:21830823

  5. Physiologically Based Pharmacokinetic Modeling of Fluorescently Labeled Block Copolymer Nanoparticles for Controlled Drug Delivery in Leukemia Therapy

    PubMed Central

    Gilkey, MJ; Krishnan, V; Scheetz, L; Jia, X; Rajasekaran, AK; Dhurjati, PS

    2015-01-01

    A physiologically based pharmacokinetic (PBPK) model was developed that describes the concentration and biodistribution of fluorescently labeled nanoparticles in mice used for the controlled delivery of dexamethasone in acute lymphoblastic leukemia (ALL) therapy. The simulated data showed initial spikes in nanoparticle concentration in the liver, spleen, and kidneys, whereas concentration in plasma decreased rapidly. These simulation results were consistent with previously published in vivo data. At shorter time scales, the simulated data predicted decrease of nanoparticles from plasma with concomitant increase in the liver, spleen, and kidneys before decaying at longer timepoints. Interestingly, the simulated data predicted an unaccounted accumulation of about 50% of the injected dose of nanoparticles. Incorporation of an additional compartment into the model justified the presence of unaccounted nanoparticles in this compartment. Our results suggest that the proposed PBPK model can be an excellent tool for prediction of optimal dose of nanoparticle-encapsulated drugs for cancer treatment.

  6. Highly quasi-monodisperse ag nanoparticles on titania nanotubes by impregnative aqueous ion exchange.

    PubMed

    Toledo-Antonio, J A; Cortes-Jácome, M A; Angeles-Chavez, C; López-Salinas, E; Quintana, P

    2009-09-01

    Silver nanoparticles were homogenously dispersed on titania nanotubes (NT), which were prepared by alkali hydrothermal methodology and dried at 373 K. Ag(+) incorporation was done by impregnative ion exchange of aqueous silver nitrate onto NT. First, Ag(+) ions incorporate into the layers of nanotube walls, and then, upon heat treatment under N(2) at 573 and 673 K, they migrate and change into Ag(2)O and Ag(0) nanoparticles, respectively. In both cases, Ag nanoparticles are highly dispersed, decorating the nanotubes in a polka-dot pattern. The Ag particle size distribution is very narrow, being ca. 4 +/- 2 nm without any observable agglomeration. The reduction of Ag(2)O into Ag(0) octahedral nanoparticles occurs spontaneously and topotactically when annealing, without the aid of any reducing agent. The population of Ag(0) nanoparticles can be controlled by adjusting the annealing temperature. An electron charge transfer from NT support to Ag(0) nanoparticles, because of a strong interaction, is responsible for considerable visible light absorption in Ag(0) nanoparticles supported on NT. PMID:19485374

  7. Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery

    PubMed Central

    Ngwuluka, Ndidi C.; Pillay, Viness; Choonara, Yahya E.; Modi, Girish; Naidoo, Dinesh; du Toit, Lisa C.; Kumar, Pradeep; Ndesendo, Valence M.K.; Khan, Riaz A.

    2011-01-01

    Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.8–43.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery. PMID:22016653

  8. Electrosprayed nanoparticles for drug delivery and pharmaceutical applications

    PubMed Central

    Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2013-01-01

    Nanotechnology based Pharma has emerged significantly and has influenced the Pharma industry up to a considerable extent. Nanoparticles technology holds a good share of the nanotech Pharma and is significant in comparison with the other domains. Electrospraying technology answers the potential needs of nanoparticle production such as scalability, reproducibility, effective encapsulation etc. Many drugs have been electrosprayed with and without polymer carriers. Drug release characteristics are improved with the incorporation of biodegradable polymer carriers which sustain the release of encapsulated drug. Electrospraying is acknowledged as an important technique for the preparation of nanoparticles with respect to pharmaceutical applications. Herein we attempted to consolidate the reports pertaining to electrospraying and their corresponding therapeutic application area. PMID:23512013

  9. Liposomes: from a clinically established drug delivery system to a nanoparticle platform for theranostic nanomedicine.

    PubMed

    Al-Jamal, Wafa' T; Kostarelos, Kostas

    2011-10-18

    For decades, clinicians have used liposomes, self-assembled lipid vesicles, as nanoscale systems to deliver encapsulated anthracycline molecules for cancer treatment. The more recent proposition to combine liposomes with nanoparticles remains at the preclinical development stages; however, such hybrid constructs present great opportunities to engineer theranostic nanoscale delivery systems, which can combine simultaneous therapeutic and imaging functions. Many novel nanoparticles of varying chemical compositions are being developed in nanotechnology laboratories, but further chemical modification is often required to make these structures compatible with the biological milieu in vitro and in vivo. Such nanoparticles have shown promise as diagnostic and therapeutic tools and generally offer a large surface area that allows covalent and non-covalent surface functionalization with hydrophilic polymers, therapeutic moieties, and targeting ligands. In most cases, such surface manipulation diminishes the theranostic properties of nanoparticles and makes them less stable. From our perspective, liposomes offer structural features that can make nanoparticles biocompatible and present a clinically proven, versatile platform for further enhancement of the pharmacological and diagnostic efficacy of nanoparticles. In this Account, we describe two examples of liposome-nanoparticle hybrids developed as theranostics: liposome-quantum dot hybrids loaded with a cytotoxic drug (doxorubicin) and artificially enveloped adenoviruses. We incorporated quantum dots into lipid bilayers, which rendered them dispersible in physiological conditions. This overall vesicular structure allowed them to be loaded with doxorubicin molecules. These structures exhibited cytotoxic activity and labeled cells both in vitro and in vivo. In an alternative design, lipid bilayers assembled around non-enveloped viral nanoparticles and altered their infection tropism in vitro and in vivo with no chemical or genetic capsid modifications. Overall, we have attempted to illustrate how alternative strategies to incorporate nanoparticles into liposomal nanostructures can overcome some of the shortcomings of nanoparticles. Such hybrid structures could offer diagnostic and therapeutic combinations suitable for biomedical and even clinical applications. PMID:21812415

  10. Drug delivery nanoparticles in skin cancers.

    PubMed

    Dianzani, Chiara; Zara, Gian Paolo; Maina, Giovanni; Pettazzoni, Piergiorgio; Pizzimenti, Stefania; Rossi, Federica; Gigliotti, Casimiro Luca; Ciamporcero, Eric Stefano; Daga, Martina; Barrera, Giuseppina

    2014-01-01

    Nanotechnology involves the engineering of functional systems at nanoscale, thus being attractive for disciplines ranging from materials science to biomedicine. One of the most active research areas of the nanotechnology is nanomedicine, which applies nanotechnology to highly specific medical interventions for prevention, diagnosis, and treatment of diseases, including cancer disease. Over the past two decades, the rapid developments in nanotechnology have allowed the incorporation of multiple therapeutic, sensing, and targeting agents into nanoparticles, for detection, prevention, and treatment of cancer diseases. Nanoparticles offer many advantages as drug carrier systems since they can improve the solubility of poorly water-soluble drugs, modify pharmacokinetics, increase drug half-life by reducing immunogenicity, improve bioavailability, and diminish drug metabolism. They can also enable a tunable release of therapeutic compounds and the simultaneous delivery of two or more drugs for combination therapy. In this review, we discuss the recent advances in the use of different types of nanoparticles for systemic and topical drug delivery in the treatment of skin cancer. In particular, the progress in the treatment with nanocarriers of basal cell carcinoma, squamous cell carcinoma, and melanoma has been reported. PMID:25101298

  11. Theranostic Upconversion Nanoparticles (I)

    PubMed Central

    Chen, Guanying; Han, Gang

    2013-01-01

    This theme issue provides a comprehensive collection of original research articles on the creation of diverse types of theranostic upconversion nanoparticles, their fundamental interactions in biology, as well as their biophotonic applications in noninvasive diagnostics and therapy. PMID:23606916

  12. Engines and nanoparticles

    Microsoft Academic Search

    David B. Kittelson

    1998-01-01

    Most of the particle number emitted by engines is in the nanoparticle range, Dp<50 nm, while most of the mass is in the accumulation mode, 50nmNanoparticles are typically hydrocarbons or sulfate and form by nucleation during dilution and cooling of the exhaust, while accumulation mode particles are mainly carbonaceous soot agglomerates formed directly by combustion. Emission standards

  13. Engineering Pharmaceutical Nanoparticles

    E-print Network

    Berkland, Cory

    2006-10-26

    Engineering Pharmaceutical Nanoparticles Cory Berkland Assistant Professor Department of Pharmaceutical Chemistry Assistant Professor Department of Chemical and Petroleum Engineering The University of Kansas 2 Acknowledgements Postdocs: David Shi....retsch.de 8 For example, the bioavailability of poorly soluble drugs can be enhanced. Spironalactone is a synthetic 17-lactone steroid. Nanoparticle suspensions of this drug dramatically enhance the drug dissolution. 9 For example, tumor accumulation via...

  14. Ferromagnetism of lightly Co-doped ZnO nanoparticles

    Microsoft Academic Search

    L. B. Duan; G. H. Rao; J. Yu; Y. C. Wang

    2008-01-01

    Zn1?xCoxO (x=0–0.04) nanoparticles were synthesized by an auto-combustion method. X-ray diffraction and Raman scattering studies confirmed the incorporation of Co into the ZnO lattice. Hysteresis loops were observed at 300 K in the samples with x=0.01–0.04, and the coercivity decreased with increasing Co content x. Temperature dependence of magnetization showed a usual steep upturn for transition metals doped ZnO at low

  15. CCMR: Metal Nanoparticles Architectures for Nanoplasmonics Applications: Synthesis and Characterizations

    NSDL National Science Digital Library

    Livenere, John

    2009-08-15

    This summer my project was to increase the size of a nano particle called Cornell Dot or C. Dot. A C. Dot is a core-shell silica nanoparticles is the development of fluorescent particles based on organic dyes covalently incorporated into the silica matrix. Reactive dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the coreshell particle.

  16. Enhancement of surface ligand display on PLGA nanoparticles with amphiphilic ligand conjugates

    PubMed Central

    Park, Jason; Mattessich, Thomas; Jay, Steven M.; Agawu, Atu; Saltzman, W. Mark; Fahmy, Tarek M.

    2013-01-01

    Biodegradable polymeric nanoparticles are widely recognized as efficacious drug delivery vehicles, yet the rational engineering of nanoparticle surfaces in order to improve biodistribution, reduce clearance, and/or improve targeting remains a significant challenge. We have previously demonstrated that an amphiphilic conjugate of avidin and palmitic acid can be used to modify poly(lactic-co-glycolic acid) (PLGA) particle surfaces to display functional avidin groups, allowing for the facile attachment of biotinylated ligands for targeting or steric stabilization. Here, we hypothesized that the incorporation, density, and stability of surface-presented avidin could be modulated through varying the lipophilicity of its fatty acid conjugate partner. We tested this hypothesis by generating a set of novel conjugates incorporating avidin and common fatty acids. We found that conjugation to linoleic acid resulted in a ?60% increase in the incorporation of avidin on the nanoparticle surface compared to avidin–palmitic acid, which exhibited the highest avidin incorporation in previous studies. Further, the linoleic acid–avidin conjugate yielded nanoparticles with enhanced ability to bind biotinylated ligands compared to the previous method; nanoparticles modified with avidin–linoleic acid bound ?170% more biotin–HRP than those made with avidin–palmitic acid and ?1300% more than particles made without conjugated avidin. Most critically, increased ligand density on anti-CD4-targeted nanoparticles formulated with the linoleic acid–avidin conjugate resulted in a 5% increase in binding of CD4+ T cells. Thus we conclude that the novel avidin–linoleic acid conjugate facilitates enhanced ligand density on PLGA nanoparticles, resulting in functional enhancement of cellular targeting. PMID:21723893

  17. Enhancement of surface ligand display on PLGA nanoparticles with amphiphilic ligand conjugates.

    PubMed

    Park, Jason; Mattessich, Thomas; Jay, Steven M; Agawu, Atu; Saltzman, W Mark; Fahmy, Tarek M

    2011-11-30

    Biodegradable polymeric nanoparticles are widely recognized as efficacious drug delivery vehicles, yet the rational engineering of nanoparticle surfaces in order to improve biodistribution, reduce clearance, and/or improve targeting remains a significant challenge. We have previously demonstrated that an amphiphilic conjugate of avidin and palmitic acid can be used to modify poly(lactic-co-glycolic acid) (PLGA) particle surfaces to display functional avidin groups, allowing for the facile attachment of biotinylated ligands for targeting or steric stabilization. Here, we hypothesized that the incorporation, density, and stability of surface-presented avidin could be modulated through varying the lipophilicity of its fatty acid conjugate partner. We tested this hypothesis by generating a set of novel conjugates incorporating avidin and common fatty acids. We found that conjugation to linoleic acid resulted in a ~60% increase in the incorporation of avidin on the nanoparticle surface compared to avidin-palmitic acid, which exhibited the highest avidin incorporation in previous studies. Further, the linoleic acid-avidin conjugate yielded nanoparticles with enhanced ability to bind biotinylated ligands compared to the previous method; nanoparticles modified with avidin-linoleic acid bound ~170% more biotin-HRP than those made with avidin-palmitic acid and ~1300% more than particles made without conjugated avidin. Most critically, increased ligand density on anti-CD4-targeted nanoparticles formulated with the linoleic acid-avidin conjugate resulted in a 5% increase in binding of CD4(+) T cells. Thus we conclude that the novel avidin-linoleic acid conjugate facilitates enhanced ligand density on PLGA nanoparticles, resulting in functional enhancement of cellular targeting. PMID:21723893

  18. Preparation and characterizations of silver incorporated polyurethane composite nanofibers via electrospinning for biomedical applications.

    PubMed

    Nirmala, R; Kalpana, Duraisamy; Navamathavan, R; Lee, Yang Soo; Kim, Hak Yong

    2013-07-01

    We report on the preparation and characterization of polyurethane (PU) nanofibers containing silver (Ag) nanoparticles were synthesized by using electrospinning. Two different approaches were adopted to incorporate the Ag nanoparticles in to PU nanofibers. In the first approach, a homogeneous solution of 10 wt% PU containing silver nitrate was electrospun to obtain PU-Ag composite nanofibers. And in the second approach, the pristine PU nanofibers were initially electrospun and then Ag nanoparticles were coated via wet casting method. The surface morphology, structure, bonding configuration, optical and thermal properties of the resultant products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UV-vis spectroscopy and thermogravimetric analysis. The antibacterial activity was tested against four common food borne pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae by minimum inhibitory concentration (MIC) method. Our results demonstrated that no bactericidal activity was detected for the pristine PU nanofibers. Further on, antibacterial activity was observed to be more pronounced for the composite nanofibers which were attributed to the presence of Ag nanoparticles in the composite nanofibers. Overall, this study demonstrates the fabrication of cheap, stable and effective nanofiber mats with excellent antimicrobial activity that can be utilized to inhibit the microbial growth associated with food stuff. PMID:23901491

  19. MICROBIAL IMPACTS OF ENGINEERED NANOPARTICLES

    EPA Science Inventory

    Reactivity at the nanometric scale is intimately linked to nanoparticle mobility and microbial sensitivity. Thus, first-order factors increasing nanoparticle reactivity should increase the rate of redox reactions with second-order effects on particle mobility and ecot...

  20. Direct hierarchical assembly of nanoparticles

    DOEpatents

    Xu, Ting; Zhao, Yue; Thorkelsson, Kari

    2014-07-22

    The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

  1. Automated Morphology Analysis of Nanoparticles

    E-print Network

    Park, Chiwoo

    2012-10-19

    The functional properties of nanoparticles highly depend on the surface morphology of the particles, so precise measurements of a particle's morphology enable reliable characterizing of the nanoparticle's properties. Obtaining the measurements...

  2. Nanoparticles for Targeted Drug Delivery

    E-print Network

    Chow, Gan-Moog

    Nanoparticles were synthesized and modified for target drug delivery. The research involved the aqueous synthesis of near infrared (NIR) sensitive Au-Au2S nanoparticles. An anti-cancer drug (cis-platin) ...

  3. Automated Morphology Analysis of Nanoparticles 

    E-print Network

    Park, Chiwoo

    2012-10-19

    The functional properties of nanoparticles highly depend on the surface morphology of the particles, so precise measurements of a particle's morphology enable reliable characterizing of the nanoparticle's properties. Obtaining the measurements...

  4. A nanoparticle-based epigenetic modulator for efficient gene modulation

    NASA Astrophysics Data System (ADS)

    Pongkulapa, Thanapat

    Modulation of gene expression through chromatin remodeling involves epigenetic mechanisms, such as histone acetylation. Acetylation is tightly regulated by two classes of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). Molecules that can regulate these enzymes by altering (activating or inhibiting) their functions have become a valuable tool for understanding cell development and diseases. HAT activators, i.e. N-(4-Chloro-(3-trifluoromethyl)phenyl)-2-ethoxybenzamide (CTB), have shown a therapeutic potential for many diseases, including cancer and neurodegeneration. However, these compounds encounter a solubility and a membrane permeability issue, which restricts their full potential for practical usage, especially for in vivo applications. To address this issue, in this work, we developed a nanoparticle-based HAT activator CTB, named Au-CTB, by incorporating a new CTB analogue onto gold nanoparticles (AuNPs) along with a poly(ethylene glycol) moiety and a nuclear localization signal (NLS) peptide to assist with solubility and membrane permeability. We found that our new CTB analogue and Au-CTB could activate HAT activity. Significantly, an increase in potency to activate HAT activity by Au-CTB proved the effectiveness of using the nanoparticle delivery platform. In addition, the versatility of Au-CTB platform permits the attachment of multiple ligands with tunable ratios on the nanoparticle surface via facile surface functionalization of gold nanoparticles. Due to its high delivery efficiency and versatility, Au-CTB can be a powerful platform for applications in epigenetic regulation of gene expression.

  5. Cell adhesion and proliferation on polyethylene grafted with Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Kasálková, N. Slepi?ková; Slepi?ka, P.; Kolská, Z.; Sajdl, P.; Ba?áková, L.; Rimpelová, S.; Švor?ík, V.

    2012-02-01

    Plasma treatment and subsequent Au nano-particles grafting of polyethylene (PE) lead to changes in surface morphology, roughness and wettability, significantly increasing the attractiveness of the material for cells. The PE samples were exposed to argon plasma. Plasma modified PE was chemically grafted by immersion to biphenyldithiol and consequently into solution of Au nano-particles. Changes in chemical structure of the modified PE were studied using X-ray Photoelectron Spectroscopy (XPS) and electrokinetic analysis ( ?-potential). The surface wettability of the modified PE samples was examined by measurement of the contact angle by standard goniometry. The surface morphology of the plasma modified PE and that grafted with Au nano-particles was studied by Atomic Force Microscopy (AFM). The modified PE samples were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Chemically bounded biphenyldithiol increases the number of the incorporated gold nano-particles and changes sample surface properties. The presence of the biphenyldithiol and the gold nano-particles on the PE surface influences dramatically adhesion and proliferation of VSMCs.

  6. Nanoparticles Engineered from Lecithin-in-Water Emulsions As A Potential Delivery System for Docetaxel

    PubMed Central

    Yanasarn, Nijaporn; Sloat, Brian R.; Cui, Zhengrong

    2009-01-01

    Docetaxel is a potent anti-cancer drug. However, there continues to be a need for alternative docetaxel delivery systems to improve its efficacy. We reported the engineering of a novel spherical nanoparticle formulation (~270 nm) from lecithin-in-water emulsions. Docetaxel can be incorporated into the nanoparticles, and the resultant docetaxel-nanoparticles were stable when stored as an aqueous suspension. The release of the docetaxel from the nanoparticles was likely caused by a combination of diffusion and Case II transport. The docetaxel-in-nanoparticles were more effective in killing tumor cells in culture than free docetaxel. Moreover, the docetaxel-nanoparticles did not cause any significant red blood cell lysis or platelet aggregation in vitro, nor did they induce detectable acute liver damage when injected intravenously into mice. Finally, compared to free docetaxel, the intravenously injected docetaxel-nanoparticles increased the accumulation of the docetaxel in a model tumor in mice by 4.5-fold. These lecithin-based nanoparticles have the potential to be a novel biocompatible and efficacious delivery system for docetaxel. PMID:19524029

  7. Nanoparticles engineered from lecithin-in-water emulsions as a potential delivery system for docetaxel.

    PubMed

    Yanasarn, Nijaporn; Sloat, Brian R; Cui, Zhengrong

    2009-09-01

    Docetaxel is a potent anticancer drug. However, there continues to be a need for alternative docetaxel delivery systems to improve its efficacy. We reported the engineering of a novel spherical nanoparticle formulation ( approximately 270 nm) from lecithin-in-water emulsions. Docetaxel can be incorporated into the nanoparticles, and the resultant docetaxel-nanoparticles were stable when stored as an aqueous suspension. The release of the docetaxel from the nanoparticles was likely caused by a combination of diffusion and Case II transport. The docetaxel-in-nanoparticles were more effective in killing tumor cells in culture than free docetaxel. Moreover, the docetaxel-nanoparticles did not cause any significant red blood cell lysis or platelet aggregation in vitro, nor did they induce detectable acute liver damage when injected intravenously into mice. Finally, compared to free docetaxel, the intravenously injected docetaxel-nanoparticles increased the accumulation of the docetaxel in a model tumor in mice by 4.5-fold. These lecithin-based nanoparticles have the potential to be a novel biocompatible and efficacious delivery system for docetaxel. PMID:19524029

  8. Synthesis of Gold and Silver Nanoparticles Stabilized with Glycosaminoglycans having Distinctive Biological Activities

    PubMed Central

    Kemp, Melissa M.; Kumar, Ashavani; Mousa, Shaymaa; Park, Tae-Joon; Ajayan, Pulickel; Kubotera, Natsuki; Mousa, Shaker

    2009-01-01

    Metal nanoparticles have been studied for their anticoagulant and anti-inflammatory efficacy in various models. Specifically, gold and silver nanoparticles exhibit properties that make these ideal candidates for biological applications. The typical synthesis of gold and silver nanoparticles incorporates contaminants that could pose further problems. Here we demonstrate a clean method of synthesizing gold and silver nanoparticles that exhibit biological functions. These nanoparticles were prepared by reducing AuCl4 and AgNO3 using heparin and hyaluronan, as both reducing and stabilizing agents. The particles show stability under physiological conditions, and narrow size distributions for heparin particles and wider distribution for hyaluronan particles. Studies show that the heparin nanoparticles exhibit anticoagulant properties. Additionally, either gold- or silver- heparin nanoparticles exhibit local anti-inflammatory properties without any significant effect on systemic hemostasis upon administration in carrageenan-induced paw edema models. In conclusion, gold and silver nanoparticles complexed with heparin demonstrated effective anticoagulant and anti-inflammatory efficacy, having potential in various local applications. PMID:19226107

  9. Nanoparticles for molecular imaging.

    PubMed

    Sheng, Yang; Liao, Lun De; Thakor, Nitish V; Tan, Mei Chee

    2014-10-01

    Imaging techniques have been instrumental in the visualization of fundamental biological processes, identification and diagnosis of diseased states and the development of structure-function relationships at the cellular, tissue and anatomical levels. Together with the advancements made in imaging techniques, complementary chemical compounds, also known as imaging probes or contrast agents, are developed to improve the visibility of the image by enhancing sensitivity, and for the identification and quantitation of specific molecular species or structures. Extensive studies have been conducted to explore the use of inorganic nanoparticles which exhibit magnetic and optical properties unique to the nano regime so as to enhance the signals sensitivity for magnetic resonance and fluorescent imaging. These physical properties are tailored by controlling the size, shape and surface properties of nanoparticles. In addition, surface modification of nanoparticles is often required to improve its stability, compatibility and functionality. Surfactants, surface-active agents, have been used to engineer the surface characteristics of nanoparticles to improved particle stability and functionality. Surfactants enhance nanoparticle stability through the reduction of surface energy, and by acting as a barrier to agglomeration through either steric hindrance or repulsive electrostatic forces. Coupling of nanoparticles with biomolecules such as antibodies or tumor targeting peptides are enabled by the presence of functional groups (e.g., carboxyl or amine groups) on surfactants. This paper provides an overview of the chemistry underlying the synthesis and surface modification of nanomaterials together with a discussion on how the physical properties (e.g., magnetic, absorption and luminescent) can be controlled. The applications of these nanoparticles for magnetic resonance, fluorescent and photoacoustic imaging techniques that do not rely on ionizing radiation are also covered in this review. PMID:25992413

  10. Synthesis of Multifunctional Nanoparticles for Cancer Diagnostics and Therapeutics

    NASA Astrophysics Data System (ADS)

    Fang, Chen

    2011-12-01

    Magnetic nanoparticles (MNPs) have attracted enormous research attention due to their unique magnetic properties that enable the detection by the non-invasive medical imaging modality---magnetic resonance imaging (MRI). By incorporating advanced features, such as specific targeting, multimodality, therapeutic delivery, the detectability and applicability of MNPs have been dramatically expanded. Smart and rational design on structure, composition and surface chemistry is essential to achieving desired properties in MNP systems, such as high sensitivity and colloidal stability, target specificity and/or multimodality. The goal of this research is to develop MNP-based platforms for the detection, diagnosis and treatment of cancer. MNPs with high contrast enhancement were coated with poly(ethylene glycol) (PEG)-based polymers to render aqueous stability and confer therapeutic-loading capability. Tumor-specific MNPs were developed by functionalization of nanoparticles with chlorotoxin (CTX) or arginine-glycine-aspartic acid (RGD) that targets, respectively, MMP-2 receptor or alphavbeta3 integrin overexpressed on a variety of cancer cells. The effects of ligands' molecular targets on the temporal and spatial distribution of MNPs within tumors were also investigated both in vitro and in vivo. All MNPs exhibited excellent long-term stability in cell culture media. CTX-labeled MNP exhibited sustained accumulation, penetration and distribution in the tumor mass. These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. To demonstrate the ability of nanoparticles as drug carrier, anthracyline chemotherapeutic drugs doxorubicin and mitoxantrone were attached to iron oxide nanoparticles. The theragnostic nanoparticles showed sufficient contrast enhancement and comparable anti-neoplastic efficacy in vitro. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications, and the functionalized nanoparticle systems retain a prolonged stability and exhibit high tumor specificity. The study would establish the foundation for future development of integrated theragnostic systems for the treatment of cancer and other complex diseases.

  11. Molecularly-Targeted Gold-Based Nanoparticles for Cancer Imaging and Near-Infrared Photothermal Therapy

    NASA Astrophysics Data System (ADS)

    Day, Emily Shannon

    2011-12-01

    This thesis advances the use of nanoparticles as multifunctional agents for molecularly-targeted cancer imaging and photothermal therapy. Cancer mortality has remained relatively unchanged for several decades, indicating a significant need for improvements in care. Researchers are evaluating strategies incorporating nanoparticles as exogenous energy absorbers to deliver heat capable of inducing cell death selectively to tumors, sparing normal tissue. Molecular targeting of nanoparticles is predicted to improve photothermal therapy by enhancing tumor retention. This hypothesis is evaluated with two types of nanoparticles. The nanoparticles utilized, silica-gold nanoshells and gold-gold sulfide nanoparticles, can convert light energy into heat to damage cancerous cells. For in vivo applications nanoparticles are usually coated with poly(ethylene glycol) (PEG) to increase blood circulation time. Here, heterobifunctional PEG links nanoparticles to targeting agents (antibodies and growth factors) to provide cell-specific binding. This approach is evaluated through a series of experiments. In vitro, antibody-coated nanoparticles can bind breast carcinoma cells expressing the targeted receptor and act as contrast agents for multiphoton microscopy prior to inducing cell death via photoablation. Furthermore, antibody-coated nanoparticles can bind tissue ex vivo at levels corresponding to receptor expression, suggesting they should bind their target even in the complex biological milieu. This is evaluated by comparing the accumulation of antibody-coated and PEG-coated nanoparticles in subcutaneous glioma tumors in mice. Contrary to expectations, antibody targeting did not yield more nanoparticles within tumors. Nevertheless, these studies established the sensitivity of glioma to photothermal therapy; mice treated with PEG-coated nanoshells experienced 57% complete tumor regression versus no regression in control mice. Subsequent experiments employed intracranial tumors to better mimic the clinical setting. These tumors are highly vascularized, so nanoparticles were addressed toward receptors abundantly expressed on tumor vessels using growth factors as a novel targeting strategy. Photothermal therapy with these vascular-targeted nanoparticles disrupted tumor vessels, leading to a 2.2-fold prolongation of median survival versus control mice. This work confirms that nanoparticle surface coating can affect biodistribution and therapeutic efficacy. With continued optimization of molecular targeting strategies, imaging and photothermal therapy mediated by nanoshells and gold-gold sulfide nanoparticles may offer an effective alternative to conventional cancer management.

  12. Hydrophobic silver nanoparticles trapped in lipid bilayers: Size distribution, bilayer phase behavior, and optical properties

    PubMed Central

    Bothun, Geoffrey D

    2008-01-01

    Background Lipid-based dispersion of nanoparticles provides a biologically inspired route to designing therapeutic agents and a means of reducing nanoparticle toxicity. Little is currently known on how the presence of nanoparticles influences lipid vesicle stability and bilayer phase behavior. In this work, the formation of aqueous lipid/nanoparticle assemblies (LNAs) consisting of hydrophobic silver-decanethiol particles (5.7 ± 1.8 nm) embedded within 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers is demonstrated as a function of the DPPC/Ag nanoparticle (AgNP) ratio. The effect of nanoparticle loading on the size distribution, bilayer phase behavior, and bilayer fluidity is determined. Concomitantly, the effect of bilayer incorporation on the optical properties of the AgNPs is also examined. Results The dispersions were stable at 50°C where the bilayers existed in a liquid crystalline state, but phase separated at 25°C where the bilayers were in a gel state, consistent with vesicle aggregation below the lipid melting temperature. Formation of bilayer-embedded nanoparticles was confirmed by differential scanning calorimetry and fluorescence anisotropy, where increasing nanoparticle concentration suppressed the lipid pretransition temperature, reduced the melting temperature, and disrupted gel phase bilayers. The characteristic surface plasmon resonance (SPR) wavelength of the embedded nanoparticles was independent of the bilayer phase; however, the SPR absorbance was dependent on vesicle aggregation. Conclusion These results suggest that lipid bilayers can distort to accommodate large hydrophobic nanoparticles, relative to the thickness of the bilayer, and may provide insight into nanoparticle/biomembrane interactions and the design of multifunctional liposomal carriers. PMID:19014492

  13. Diclofenac sodium-loaded solid lipid nanoparticles prepared by emulsion\\/solvent evaporation method

    Microsoft Academic Search

    Dongfei LiuSunmin; Sunmin Jiang; Hong Shen; Shan Qin; Juanjuan Liu; Qing Zhang; Rui Li; Qunwei Xu

    2011-01-01

    The preparation of solid lipid nanoparticles (SLNs) suffers from the drawback of poor incorporation of water-soluble drugs.\\u000a The aim of this study was therefore to assess various formulation and process parameters to enhance the incorporation of a\\u000a water-soluble drug (diclofenac sodium, DS) into SLNs prepared by the emulsion\\/solvent evaporation method. Results showed that\\u000a the entrapment efficiency (EE) of DS was

  14. SYNTHESIS AND CHARACTERIZATION OF NANOPARTICLES

    E-print Network

    Ding, Yu

    SYNTHESIS AND CHARACTERIZATION OF NANOPARTICLES Lokesh Kulkarni Dept. of Industrial and Systems of gold nanoparticles: - Chemicals: Auric salt (source of Au ions), sodium citrate (reducing agent - Process: See figure - Capable of producing spherical gold nanoparticles of around 10-20 nm in diameter

  15. Antimicrobial effects of silver nanoparticles

    Microsoft Academic Search

    Jun Sung Kim; Eunye Kuk; Kyeong Nam Yu; Jong-Ho Kim; Sung Jin Park; Hu Jang Lee; So Hyun Kim; Young Kyung Park; Yong Ho Park; Cheol-Yong Hwang; Yong-Kwon Kim; Yoon-Sik Lee; Dae Hong Jeong; Myung-Haing Cho

    2007-01-01

    The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli,

  16. Paper surfaces functionalized by nanoparticles.

    PubMed

    Ngo, Ying Hui; Li, Dan; Simon, George P; Garnier, Gil

    2011-03-15

    Nanomaterials with unique electronic, optical and catalytic properties have recently been at the forefront of research due to their tremendous range of applications. Taking gold, silver and titania nanoparticles as examples, we have reviewed the current research works on paper functionalized by these nanoparticles. The functionalization of paper with only a very small concentration of nanoparticles is able to produce devices with excellent photocatalytic, antibacterial, anti-counterfeiting, Surface Enhanced Raman Scattering (SERS) and Surface Plasmon Resonance (SPR) performances. This review presents a brief overview of the properties of gold, silver and titania nanoparticles which contribute to the major applications of nanoparticles-functionalized paper. Different preparation methods of the nanoparticles-functionalized paper are reviewed, focusing on their ability to control the morphology and structure of paper as well as the spatial location and adsorption state of nanoparticles which are critical in achieving their optimum applications. In addition, main applications of the nanoparticles-functionalized papers are highlighted and their critical challenges are discussed, followed by perspectives on the future direction in this research field. Whilst a few studies to date have characterized the distribution of nanoparticles on paper substrates, none have yet optimized paper as a nanoparticles' substrate. There remains a strong need to improve understanding on the optimum adsorption state of nanoparticles on paper and the heterogeneity effects of paper on the properties of these nanoparticles. PMID:21324427

  17. Preparations of bifunctional polymeric beads simultaneously incorporated with fluorescent quantum dots and magnetic nanocrystals

    NASA Astrophysics Data System (ADS)

    Tu, Chifeng; Yang, Yunhua; Gao, Mingyuan

    2008-03-01

    Bifunctional polystyrene beads simultaneously incorporated with fluorescent CdTe quantum dots (Q-dots) and superparamagnetic Fe3O4 nanocrystals were prepared by a modified mini-emulsion polymerization method, in which polymerizable surfactants were used as both phase transfer agent for aqueous colloidal nanoparticles and emulsifier. In addition, silica coating was also introduced to Fe3O4 nanocrystals for regulating the internal structure of the composite beads. Transmission electron microscopy, confocal fluorescence microscopy and conventional spectroscopy were used to characterize the composite beads, as well as the polymerizable surfactant-coated CdTe Q-dots and silica-coated Fe3O4 nanoparticles. Different mixing methods were also attempted in order to vary the size of the resultant bifunctional beads.

  18. Single-Antibody, Targeted Nanoparticle Delivery of Camptothecin

    PubMed Central

    Han, Han; Davis, Mark E.

    2013-01-01

    We have developed a new method for assembling targeted nanoparticles that utilizes the complexation between targeting agents that contain boronic acids and polymer-drug conjugates that possess diols. Here, we report the first in vivo, antitumor results of a nanoparticle formed via this new assembly methodology. A nanoparticle consisting of a mucic acid polymer conjugate of camptothecin (CPT), MAP-CPT; and containing on average one Herceptin antibody is investigated in nude mice bearing HER2 overexpressing BT-474 human breast cancer tumors. Nontargeted MAP-CPT and antibody-containing MAP-CPT nanoparticles of ca. 30–40 nm diameter and slightly negative zeta potential show prolonged in vivo circulation and similar biodistributions after intravenous tail vein injections in mice. The maximum tolerated dose (MTD) of the nontargeted and Herceptin-containing MAP-CPT nanoparticles are found to be 10 and 8 mg CPT/kg, respectively, in mice. Mice bearing BT-474 human breast tumors treated with nontargeted MAP-CPT nanoparticles at 8 mg CPT/kg show significant tumor growth inhibition (mean tumor volume of 63 mm3) when compared to Irinotecan at 80 mg/kg (mean tumor volume of 575 mm3) and CPT at 8 mg/kg (mean tumor volume of 808 mm3) at the end of the study. Herceptin antibody treatment at 5.9 mg/kg results in complete tumor regressions in 5 out of 8 mice, with a mean tumor volume of 60 mm3 at the end of the study. Mice treated with MAP-CPT nanoparticles at 1 mg CPT/kg do not show tumor inhibition. However, all mice receiving administrations of MAP-CPT nanoparticles (1 mg CPT/kg) that contain on average a single Herceptin molecule per nanoparticle (5.9 mg Herceptin equivalent/kg) show complete tumor regression by the end of the study. These results demonstrate that the antitumor efficacy of nanoparticles carrying anticancer drugs can be enhanced by incorporating on average a single antibody. PMID:23676007

  19. Physical properties of griseofulvin-lipid nanoparticles in suspension and their novel interaction mechanism with saccharide during freeze-drying.

    PubMed

    Kamiya, Seitaro; Kurita, Takurou; Miyagishima, Atsuo; Itai, Shigeru; Arakawa, Masayuki

    2010-03-01

    Size reduction of drug particles to the nanoscale is important in improving the dissolution rate of poorly water-soluble drugs. The aim of this study was to investigate the physicochemical properties of griseofulvin (GF)-lipid nanoparticles and the interactions between GF-lipid nanoparticles and various saccharides during freeze-drying. The phase transition temperature of the GF-lipid nanoparticle suspension was 56.8 degrees C, whereas that of the lipid nanoparticle suspension alone was 57.9 degrees C, indicating that the GF crystals were incorporated into the lipid phase. The mean particle size of a rehydrated suspension of xylose-containing freeze-dried GF-lipid nanoparticles was about 220 nm. However, the mean particle size on the rehydration of nanoparticles containing mannose (monosaccharide), fructose (disaccharide), lactose (disaccharide), or raffinose (trisaccharide) was about 60 nm, suggesting that these saccharides prevented aggregation during the freeze-drying process. Powder X-ray diffraction revealed that xylose existed in the crystalline state in the freeze-dried nanoparticles, whereas the other saccharides existed in amorphous states. Thus, the crystallization of the saccharide was found to be strongly correlated with the aggregation property of the nanoparticles. In the case of freeze-dried xylose, the nanoparticles were squeezed out as the saccharine crystal lattice arranged itself regularly. Then, the ejected nanoparticles were aggregated. In contrast, in the case of the other freeze-dried saccharide, the saccharide remained incorporated with the GF-lipid nanoparticles because its crystal lattice was arranged irregularly. Thus, the particle size was maintained. PMID:20018239

  20. Ordered mesoporous silica nanoparticles with and without embedded iron oxide nanoparticles: structure evolution during synthesis

    E-print Network

    Gruner, Sol M.

    Ordered mesoporous silica nanoparticles with and without embedded iron oxide nanoparticles of hexagonally ordered mesoporous silica nanoparticles with and without embedded iron oxide particles. Oleic acid surfactant, hexadecyltrimethylammonium bromide (CTAB). MCM-41 type silica and composite nanoparticles

  1. Dual drug-loaded nanoparticles on self-integrated scaffold for controlled delivery

    PubMed Central

    Bennet, Devasier; Marimuthu, Mohana; Kim, Sanghyo; An, Jeongho

    2012-01-01

    Antioxidant (quercetin) and hypoglycemic (voglibose) drug-loaded poly-D,L-lactideco-glycolide nanoparticles were successfully synthesized using the solvent evaporation method. The dual drug-loaded nanoparticles were incorporated into a scaffold film using a solvent casting method, creating a controlled transdermal drug-delivery system. Key features of the film formulation were achieved utilizing several ratios of excipients, including polyvinyl alcohol, polyethylene glycol, hyaluronic acid, xylitol, and alginate. The scaffold film showed superior encapsulation capability and swelling properties, with various potential applications, eg, the treatment of diabetes-associated complications. Structural and light scattering characterization confirmed a spherical shape and a mean particle size distribution of 41.3 nm for nanoparticles in the scaffold film. Spectroscopy revealed a stable polymer structure before and after encapsulation. The thermoresponsive swelling properties of the film were evaluated according to temperature and pH. Scaffold films incorporating dual drug-loaded nanoparticles showed remarkably high thermoresponsivity, cell compatibility, and ex vivo drug-release behavior. In addition, the hybrid film formulation showed enhanced cell adhesion and proliferation. These dual drug-loaded nanoparticles incorporated into a scaffold film may be promising for development into a transdermal drug-delivery system. PMID:22888222

  2. Constraints on Noun Incorporation in Korean.

    ERIC Educational Resources Information Center

    Khym, Hangyoo

    1997-01-01

    A study of the noun incorporation phenomenon in Korean suggests that noun incorporation occurs at D-structure and obeys the Head Movement Constraint syntactically, and the Theme-Only Constraint semantically. First, the structure of "sunrise"-type words is identified, showing that before derivation through nominalization of the affix "-i,"…

  3. Incorporating Sociology into Community Service Classes

    ERIC Educational Resources Information Center

    Hochschild, Thomas R., Jr.; Farley, Matthew; Chee, Vanessa

    2014-01-01

    Sociologists and instructors who teach about community service share an affinity for understanding and addressing social problems. While many studies have demonstrated the benefits of incorporating community service into sociology courses, we examine the benefits of incorporating sociological content into community service classes. The authors…

  4. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Abdominal Assembly, incorporated by reference in §§ 572.181 and 572.186; (ix) Drawing No. 175-5500, Lumbar Spine Assembly, incorporated by reference in §§ 572.181 and 572.187; (x) Drawing No. 175-6000, Pelvis Assembly,...

  5. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Abdominal Assembly, incorporated by reference in §§ 572.181 and 572.186; (ix) Drawing No. 175-5500, Lumbar Spine Assembly, incorporated by reference in §§ 572.181 and 572.187; (x) Drawing No. 175-6000, Pelvis Assembly,...

  6. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Abdominal Assembly, incorporated by reference in §§ 572.181 and 572.186; (ix) Drawing No. 175-5500, Lumbar Spine Assembly, incorporated by reference in §§ 572.181 and 572.187; (x) Drawing No. 175-6000, Pelvis Assembly,...

  7. Ribonucleotide incorporation by yeast DNA polymerase ?

    PubMed Central

    Makarova, Alena V.; McElhinny, Stephanie A. Nick; Watts, Brian E.; Kunkel, Thomas A.; Burgers, Peter M.

    2015-01-01

    During replication in yeast, the three B family DNA replicases frequently incorporate ribonucleotides (rNMPs) into DNA, and their presence in the nuclear genome can affect genome stability. This prompted us to examine ribonucleotide incorporation by the fourth B family member, Pol ? the enzyme responsible for the majority of damage-induced mutagenesis in eukaryotes. We first show that Pol ? inserts rNMPs into DNA and can extend primer termini containing 3’-ribonucleotides. We then measure rNMP incorporation by Pol ? in the presence of its cofactors, RPA, RFC and PCNA and at normal cellular dNTP and rNTP concentrations that exist under unstressed conditions. Under these conditions, Pol ? stably incorporates one rNMP for every 200-300 dNMPs incorporated, a frequency that is slightly higher than for the high fidelity replicative DNA polymerases. Under damage-induced conditions wherein cellular dNTP concentrations are elevated 5-fold, Pol ? only incorporates one rNMP per 1,300 dNMPs. Functional interaction of Pol ? with the mutasome assembly factor Rev1 gives comparable rNMP incorporation frequencies. These results suggest that ribonucleotide incorporation into DNA during Pol ?-mediated mutagenesis in vivo may be rare. PMID:24674899

  8. Incorporation and distribution of strontium in bone

    Microsoft Academic Search

    S. G Dahl; P Allain; P. J Marie; Y Mauras; G Boivin; P Ammann; Y Tsouderos; P. D Delmas; C Christiansen

    2001-01-01

    The distribution and incorporation of strontium into bone has been examined in rats, monkeys, and humans after oral administration of strontium (either strontium chloride or strontium ranelate). After repeated administration for a sufficient period of time (at least 4 weeks in rats), strontium incorporation into bone reaches a plateau level. This plateau appears to be lower in females than in

  9. Optimal power flow incorporating voltage collapse constraints

    Microsoft Academic Search

    William Rosehart; C. Canizares; Victor Quintana

    1999-01-01

    The paper presents applications of optimization techniques to voltage collapse studies. First a “maximum distance to voltage collapse” algorithm that incorporates constraints on the current operating conditions is presented. Second, an optimal power flow formulation that incorporates voltage-stability criteria is proposed. The algorithms are tested on a 30-bus system using a standard power flow model, where the effect of limits

  10. A facile route for growth of CNTs on Si@hard carbon for conductive agent incorporating anodes for lithium-ion batteries.

    PubMed

    Kim, Chanhoon; Choi, Sinho; Yoo, Seungmin; Kwon, Dohyoung; Ko, Seunghee; Kim, Ju-Myung; Lee, Sang-Young; Kim, Il-Doo; Park, Soojin

    2015-06-25

    Conductive agent incorporating Si anodes consisting of directly grown carbon nanotubes on hard carbon encapsulating Si nanoparticles were prepared by a one-pot chemical vapour deposition process. Owing to this fabulous structure, Si-based anodes exhibit excellent cycle retention and rate capability with a high-mass-loading of 3.5 mg cm(-2). PMID:26077514

  11. Superbackscattering nanoparticle dimers

    NASA Astrophysics Data System (ADS)

    Liberal, Iñigo; Ederra, Iñigo; Gonzalo, Ramón; Ziolkowski, Richard W.

    2015-07-01

    The theory and design of superbackscattering nanoparticle dimers are presented. We analytically derive the optimal configurations and the upper bound of their backscattering cross-sections. In particular, it is demonstrated that electrically small nanoparticle dimers can enhance the backscattering by a factor of 6.25 with respect to single dipolar particles. We demonstrate that optimal designs approaching this theoretical limit can be found by using a simple circuit model. The study of practical implementations based on plasmonic and high-permittivity particles has been also addressed. Moreover, the numerical examples reveal that the dimers can attain close to a fourfold enhancement of the single nanoparticle response even in the presence of high losses.

  12. Superbackscattering nanoparticle dimers.

    PubMed

    Liberal, Iñigo; Ederra, Iñigo; Gonzalo, Ramón; Ziolkowski, Richard W

    2015-07-10

    The theory and design of superbackscattering nanoparticle dimers are presented. We analytically derive the optimal configurations and the upper bound of their backscattering cross-sections. In particular, it is demonstrated that electrically small nanoparticle dimers can enhance the backscattering by a factor of 6.25 with respect to single dipolar particles. We demonstrate that optimal designs approaching this theoretical limit can be found by using a simple circuit model. The study of practical implementations based on plasmonic and high-permittivity particles has been also addressed. Moreover, the numerical examples reveal that the dimers can attain close to a fourfold enhancement of the single nanoparticle response even in the presence of high losses. PMID:26081943

  13. PEGylated Inorganic Nanoparticles

    SciTech Connect

    Karakoti, Ajay S.; Das, Soumya; Thevuthasan, Suntharampillai; Seal, Sudipta

    2011-02-25

    Application of inorganic nanoparticles in diagnosis and therapy has become a critical component in targeted treatment of diseases. The surface modification of inorganic oxides is important for providing diversity in size, shape, solubility, long term stability and attachment of selective functional groups. PEGylation of surfaces is a key strategic approach for providing stealth characteristics to nanomaterials otherwise identified as foreign materials by human body. The current review describes the role of surface modification of oxides by polyethylene glycol (PEG) in providing versatile characteristics to inorganic oxide nanoparticles with a focus on their biomedical applications. The role of PEG as structure directing agent in synthesis of oxides is also captured in this short review.

  14. Nanoparticles from renewable polymers.

    PubMed

    Wurm, Frederik R; Weiss, Clemens K

    2014-01-01

    The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights (polysaccharides, polyesters, lignin) or by complex structure (proteins, lignin). This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications. PMID:25101259

  15. Nanoparticles from Renewable Polymers

    NASA Astrophysics Data System (ADS)

    Wurm, Frederik; Weiss, Clemens

    2014-07-01

    The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights polysaccharides, polyesters, lignin) or by complex structure (proteins, lignin). This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications.

  16. Nanoparticle shuttle memory

    DOEpatents

    Zettl, Alex Karlwalter (Kensington, CA)

    2012-03-06

    A device for storing data using nanoparticle shuttle memory having a nanotube. The nanotube has a first end and a second end. A first electrode is electrically connected to the first end of the nanotube. A second electrode is electrically connected to the second end of the nanotube. The nanotube has an enclosed nanoparticle shuttle. A switched voltage source is electrically connected to the first electrode and the second electrode, whereby a voltage may be controllably applied across the nanotube. A resistance meter is also connected to the first electrode and the second electrode, whereby the electrical resistance across the nanotube can be determined.

  17. Thermally stable nanoparticles on supports

    SciTech Connect

    Roldan Cuenya, Beatriz; Naitabdi, Ahmed R.; Behafarid, Farzad

    2012-11-13

    An inverse micelle-based method for forming nanoparticles on supports includes dissolving a polymeric material in a solvent to provide a micelle solution. A nanoparticle source is dissolved in the micelle solution. A plurality of micelles having a nanoparticle in their core and an outer polymeric coating layer are formed in the micelle solution. The micelles are applied to a support. The polymeric coating layer is then removed from the micelles to expose the nanoparticles. A supported catalyst includes a nanocrystalline powder, thin film, or single crystal support. Metal nanoparticles having a median size from 0.5 nm to 25 nm, a size distribution having a standard deviation .ltoreq.0.1 of their median size are on or embedded in the support. The plurality of metal nanoparticles are dispersed and in a periodic arrangement. The metal nanoparticles maintain their periodic arrangement and size distribution following heat treatments of at least 1,000.degree. C.

  18. Aerodynamic Focusing of Nanoparticles: II. Numerical Simulation of Particle Motion Through Aerodynamic Lenses

    Microsoft Academic Search

    Xiaoliang Wang; Ashok Gidwani; Steven L. Girshick; Peter H. McMurry

    2005-01-01

    We have developed a numerical simulation methodology that is able to accurately characterize the focusing performance of aerodynamic lens systems. The commercial computational fluid dynamics (CFD) software FLUENT was used to simulate the gas flow field. Particle trajectories were tracked using the Lagrangian approach. Brownian motion of nanoparticles was successfully incorporated in our numerical simulations. This simulation tool was then

  19. The influence of surface conductivity on the apparent zeta potential of TiO2 nanoparticles

    E-print Network

    Paris-Sud XI, Université de

    , the intrinsic zeta potential can have a larger amplitude, even in the case of simple 1:1 electrolytes like NaCl and KCl. Surface conductance of TiO2 nanoparticles immersed in a NaCl solution is estimated using a surface complexation model, and this parameter and particle size are incorporated into Henry's model

  20. Enhancement of perovskite-based solar cells employing core-shell metal nanoparticles.

    PubMed

    Zhang, Wei; Saliba, Michael; Stranks, Samuel D; Sun, Yao; Shi, Xian; Wiesner, Ulrich; Snaith, Henry J

    2013-09-11

    Recently, inorganic and hybrid light absorbers such as quantum dots and organometal halide perovskites have been studied and applied in fabricating thin-film photovoltaic devices because of their low-cost and potential for high efficiency. Further boosting the performance of solution processed thin-film solar cells without detrimentally increasing the complexity of the device architecture is critically important for commercialization. Here, we demonstrate photocurrent and efficiency enhancement in meso-superstructured organometal halide perovskite solar cells incorporating core-shell Au@SiO2 nanoparticles (NPs) delivering a device efficiency of up to 11.4%. We attribute the origin of enhanced photocurrent to a previously unobserved and unexpected mechanism of reduced exciton binding energy with the incorporation of the metal nanoparticles, rather than enhanced light absorption. Our findings represent a new aspect and lever for the application of metal nanoparticles in photovoltaics and could lead to facile tuning of exciton binding energies in perovskite semiconductors. PMID:23947387

  1. Interplay of hydrogen treatment and nitrogen doping in ZnO nanoparticles: a first-principles study

    NASA Astrophysics Data System (ADS)

    Gutjahr, Johann; Sakong, Sung; Kratzer, Peter

    2014-04-01

    With the help of density functional calculations using the HSE and PBE functionals, it is shown that incorporation of nitrogen into ZnO nanoparticles is energetically less costly compared to ZnO bulk, due to charge transfer between Zn dangling bonds and the NO impurity. Neutral NO results after full passivation of the doped nanoparticles by a treatment with atomic hydrogen. A nanocomposite made from such ZnO particles could show thermally activated p-type hopping conductivity.

  2. THE INCORPORATION OF DEMOCRACY: JUSTICE KENNEDY'S PHILOSOPHY OF POLITICAL

    E-print Network

    Finzi, Adrien

    1783 THE INCORPORATION OF DEMOCRACY: JUSTICE KENNEDY'S PHILOSOPHY OF POLITICAL PARTICIPATION. The Incorporation of Democracy .............................................. 1806 V. IMPLICATIONS FOR CAMPAIGN

  3. Enhancement of the fluorescence of triphenylmethane dyes caused by their interaction with nanoparticles from ?-diketonate complexes

    NASA Astrophysics Data System (ADS)

    Sveshnikova, E. B.; Ermolaev, V. L.

    2014-08-01

    We have studied the absorption and fluorescence spectra of Malachite Green and Crystal Violet in aqueous and alcoholic-aqueous solutions in which nanoparticles from Ln(III) and Sc(III) diketonates are formed at concentrations of complexes in a solution of 5-30 ?M. We have shown that, if the concentrations of the dyes in the solution are lower than 0.5 ?M, dye molecules are incorporated completely into nanoparticles or are precipitated onto their surface. The fluorescence intensity of these incorporated and adsorbed Malachite Green and Crystal Violet molecules increases by several orders of magnitude compared to the solution, which takes place because of a sharp increase in the fluorescence quantum yields of these dyes and at the expense of the sensitization of their fluorescence upon energy transfer from ?-diketonate complexes entering into the composition of nanoparticles. We have shown that, if there is no concentration quenching, the values of the fluorescence quantum yield of the Crystal Violet dye incorporated into nanoparticles and adsorbed on their surface vary from 0.06 to 0.13, i.e., are close to the fluorescence quantum yield of this dye in solid solutions of sucrose acetate at room temperature. The independence of the fluorescence quantum yield of Crystal Violet on the morphology of nanoparticles testifies to a high binding constant of complexes and the dye. The considerable fluorescence quantum yields of triphenylmethane dyes in nanoparticles and sensitization of their fluorescence by nanoparticle-forming complexes make it possible to determine the concentration of these dyes in aqueous solutions by the luminescent method in the range of up to 1 nM.

  4. The preparation of size-controlled functionalized polymeric nanoparticles in micelles

    NASA Astrophysics Data System (ADS)

    Vakurov, Alexander; Pchelintsev, Nikolay A.; Forde, Jessica; Ó'Fágáin, Ciaran; Gibson, Tim; Millner, Paul

    2009-07-01

    The reverse micellar system of dioctyl-sulfosuccinate (AOT)/octane and toluene have been used as a template for polymerization of acrylamide (AA)/bisacrylamide (BAA)-based functionalized polymeric nanoparticles. Such nanoparticles are typically sized between 20 and 90 nm. They can be synthesized with different functional groups according to the monomers added to the polymerization mixture. In our experiments the nanoparticles carried amino and carboxyl groups following incorporation of allylamine (AAm) or methacrylic acid (MAA) monomers, respectively. The available amine or carboxyl groups can then be used for immobilization of enzymes or other biomolecules. These enzymes, subtilisin, laccase and lipase, were immobilized onto polyAA/BAA/MAA nanoparticles covalently after activating the MAA carboxylic groups with Woodward's K reagent. Non-covalent immobilization via electrostatic interaction was also performed.

  5. Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system

    NASA Astrophysics Data System (ADS)

    Li, Linlin; Chen, Dong; Zhang, Yanqi; Deng, Zhengtao; Ren, Xiangling; Meng, Xianwei; Tang, Fangqiong; Ren, Jun; Zhang, Lin

    2007-10-01

    An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties and drug release behaviors. The system showed superparamagnetic and strong fluorescent properties, and was used as a controlled drug release vehicle, which showed pH-sensitive drug release over a long time. The composite magnetic and fluorescent chitosan nanoparticles are potential candidates as a smart drug delivery system.

  6. A New Class of Silica Crosslinked Micellar Core-Shell /nanoparticles."

    SciTech Connect

    Huo, Qisheng; Liu, Jun; Wang, Li Q.; Jiang, Yingbing; Lambert, Timothy N.; Fang, Erica

    2006-05-17

    Micellar nanoparticles made of surfactants and polymers have attracted wide attention in the materials and biomedical community for controlled drug delivery, molecular imaging and sensing; however, their long-term stability remains a topic of intense study. Here we report a new class of robust, ultrafine (10nm) silica core-shell nanoparticles formed from silica crosslinked, individual block copolymer micelles. Compared with pure polymer micelles, the new core-shell nanoparticles have significantly improved stability and do not break down during dilution. They also achieve much higher loading capacity for a wide range of chemicals, with the entrapped molecules slowly released over a much longer period of time. A wide range of functional groups can be easily incorporated through co-condensation with the silica matrix. The potential to deliver hydrophobic agents into cancer cells has been demonstrated. Because of their unique properties, these novel core-shell nanoparticles could potentially provide a new nanomedicine platform for imaging, detection and treatment.

  7. Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications

    PubMed Central

    Zhong, Tuhua; Oporto, Gloria S.; Jaczynski, Jacek; Jiang, Changle

    2015-01-01

    Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0?nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenic Escherichia coli DH5? to the nanocomposite films results in up to 5-log microbial reduction. PMID:26137482

  8. Photoswitchable oligonucleotide-modified gold nanoparticles: controlling hybridization stringency with photon dose.

    PubMed

    Yan, Yunqi; Chen, Jennifer I L; Ginger, David S

    2012-05-01

    We describe a new class of stimulus-responsive DNA-functionalized gold nanoparticles that incorporate azobenzene-modified oligonucleotides. Beyond the classic directed assembly and sensing behaviors associated with oligonucleotide-modified nanoparticles, these particles also exhibit reversible photoswitching of their assembly behavior. Exposure to UV light induces a trans-cis isomerization of the azobenzene which destabilizes the DNA duplex, resulting in dissociation of the nanoparticle assemblies. The isomerization is reversible upon exposure to blue light, resulting in rehybridization and reassembly of the DNA-linked nanoparticle clusters. We show that perfectly complementary and partially mismatched strands exhibit clearly distinguishable photoinduced melting properties, and we demonstrate that photon dose can thus be used in place of temperature or ionic strength to control hybridization stringency with the ability to discriminate single-base mismatches. PMID:22493996

  9. Imaging the delivery of brain-penetrating PLGA nanoparticles in the brain using magnetic resonance.

    PubMed

    Strohbehn, Garth; Coman, Daniel; Han, Liang; Ragheb, Ragy R T; Fahmy, Tarek M; Huttner, Anita J; Hyder, Fahmeed; Piepmeier, Joseph M; Saltzman, W Mark; Zhou, Jiangbing

    2015-02-01

    Current therapy for glioblastoma multiforme (GBM) is largely ineffective, with nearly universal tumor recurrence. The failure of current therapy is primarily due to the lack of approaches for the efficient delivery of therapeutics to diffuse tumors in the brain. In our prior study, we developed brain-penetrating nanoparticles that are capable of penetrating brain tissue and distribute over clinically relevant volumes when administered via convection-enhanced delivery (CED). We demonstrated that these particles are capable of efficient delivery of chemotherapeutics to diffuse tumors in the brain, indicating that they may serve as a groundbreaking approach for the treatment of GBM. In the original study, nanoparticles in the brain were imaged using positron emission tomography (PET). However, clinical translation of this delivery platform can be enabled by engineering a non-invasive detection modality using magnetic resonance imaging (MRI). For this purpose, we developed chemistry to incorporate superparamagnetic iron oxide (SPIO) into the brain-penetrating nanoparticles. We demonstrated that SPIO-loaded nanoparticles, which retain the same morphology as nanoparticles without SPIO, have an excellent transverse (T(2)) relaxivity. After CED, the distribution of nanoparticles in the brain (i.e., in the vicinity of injection site) can be detected using MRI and the long-lasting signal attenuation of SPIO-loaded brain-penetrating nanoparticles lasted over a one-month timecourse. Development of these nanoparticles is significant as, in future clinical applications, co-administration of SPIO-loaded nanoparticles will allow for intraoperative monitoring of particle distribution in the brain to ensure drug-loaded nanoparticles reach tumors as well as for monitoring the therapeutic benefit with time and to evaluate tumor relapse patterns. PMID:25403507

  10. Study of magnetic nanoparticles and overcoatings for biological applications including a sensor device

    NASA Astrophysics Data System (ADS)

    Grancharov, Stephanie G.

    I. A general introduction to the field of nanomaterials is presented, highlighting their special attributes and characteristics. Nanoparticles in general are discussed with respect to their structure, form and properties. Magnetic particles in particular are highlighted, especially the iron oxides. The importance and interest of integrating these materials with biological media is discussed, with emphasis on transferring particles from one medium to another, and subsequent modification of surfaces with different types of materials. II. A general route to making magnetic iron oxide nanoparticles is explained, both as maghemite and magnetite, including properties of the particles and characterization. A novel method of producing magnetite particles without a ligand is then presented, with subsequent characterization and properties described. III. Attempts to coat iron oxide nanoparticles with a view to creating biofunctional magnetic nanoparticles are presented, using a gold overcoating method. Methods of synthesis and characterization are examined, with unique problems to core-shell structures analyzed. IV. Solubility of nanoparticles in both aqueous and organic media is discussed and examined. The subsequent functionalization of the surface of maghemite and magnetite nanoparticles with a variety of biomaterials including block copolypeptides, phospholipids and carboxydextran is then presented. These methods are integral to the use of magnetic nanoparticles in biological applications, and therefore their properties are examined once tailored with these molecules. V. A new type of magnetic nanoparticle sensor-type device is described. This device integrates bio-and DNA-functionalized nanoparticles with conjugate functionalized silicon dioxide surfaces. These techniques to pattern particles to a surface are then incorporated into a device with a magnetic tunnel junction, which measures magnetoresistance in the presence of an external magnetic field. This configuration thereby introduces a new way to detect magnetic nanoparticles via their magnetic properties after conjugation via biological entities.

  11. Noninvasive Fluorescence Resonance Energy Transfer Imaging of in vivo Premature Drug Release from Polymeric Nanoparticles

    PubMed Central

    Zou, Peng; Chen, Hongwei; Paholak, Hayley J.; Sun, Duxin

    2013-01-01

    Understanding in vivo drug release kinetics is critical for the development of nanoparticle-based delivery systems. In this study, we developed a fluorescence resonance energy transfer (FRET) imaging approach to noninvasively monitor in vitro and in vivo cargo release from polymeric nanoparticles. The FRET donor dye (DiO or DiD) and acceptor dye (DiI or DiR) were individually encapsulated into poly(ethylene oxide)-b-polystyrene (PEO-PS) nanoparticles. When DiO (donor) nanoparticles and DiI (acceptor) nanoparticles were co-incubated with cancer cells for 2 h, increased FRET signals were observed from cell membranes, suggesting rapid release of DiO and DiI to cell membranes. Similarly, increased FRET ratios were detected in nude mice after intravenous co-administration of DiD (donor) nanoparticles and DiR (acceptor) nanoparticles. In contrast, another group of nude mice i.v. administrated with DiD/DiR co-loaded nanoparticles showed decreased FRET ratios. Based on the difference in FRET ratios between the two groups, in vivo DiD/DiR release half-life from PEO-PS nanoparticles was determined to be 9.2 min. In addition, it was observed that the presence of cell membranes facilitated burst release of lipophilic cargos while incorporation of oleic acid-coated iron oxide into PEO-PS nanoparticles slowed the release of DiD/DiR to cell membranes. The developed in vitro and in vivo FRET imaging techniques can be used to screening stable nano-formulations for lipophilic drug delivery. PMID:24033270

  12. Lattice-patterned LC-polymer composites containing various nanoparticles as additives

    PubMed Central

    2012-01-01

    In this study, we show the effect of various nanoparticle additives on phase separation behavior of a lattice-patterned liquid crystal [LC]-polymer composite system and on interfacial properties between the LC and polymer. Lattice-patterned LC-polymer composites were fabricated by exposing to UV light a mixture of a prepolymer, an LC, and SiO2 nanoparticles positioned under a patterned photomask. This resulted in the formation of an LC and prepolymer region through phase separation. We found that the incorporation of SiO2 nanoparticles significantly affected the electro-optical properties of the lattice-patterned LC-polymer composites. This effect is a fundamental characteristic of flexible displays. The electro-optical properties depend on the size and surface functional groups of the SiO2 nanoparticles. Compared with untreated pristine SiO2 nanoparticles, which adversely affect the performance of LC molecules surrounded by polymer walls, SiO2 nanoparticles with surface functional groups were found to improve the electro-optical properties of the lattice-patterned LC-polymer composites by increasing the quantity of SiO2 nanoparticles. The surface functional groups of the SiO2 nanoparticles were closely related to the distribution of SiO2 nanoparticles in the LC-polymer composites, and they influenced the electro-optical properties of the LC molecules. It is clear from our work that the introduction of nanoparticles into a lattice-patterned LC-polymer composite provides a method for controlling and improving the composite's electro-optical properties. This technique can be used to produce flexible substrates for various flexible electronic devices. PMID:22222011

  13. Photosensitizer-doped conjugated polymer nanoparticles for simultaneous two-photon imaging and two-photon photodynamic therapy in living cells

    NASA Astrophysics Data System (ADS)

    Shen, Xiaoqin; Li, Lin; Wu, Hao; Yao, Shao Q.; Xu, Qing-Hua

    2011-12-01

    Photosensitizer doped conjugated polymer nanoparticles have been prepared by incorporating polyoxyethylene nonylphenylether (CO-520) into the nanoparticles using a re-precipitation method. The conjugated polymer, poly[9,9-dibromohexylfluorene-2,7-ylenethylene-alt-1,4-(2,5-dimethoxy)phenylene] (PFEMO), was used as the host matrix to disperse tetraphenylporphyrin (TPP) and an energy donor to enhance the two-photon excitation properties of TPP. These CO-520 incorporated, TPP-doped PFEMO nanoparticles are stable and have low cytotoxicity in the dark. The TPP emission of the nanoparticles was found to be enhanced by about 20 times by PFEMO under two-photon excitation. The nanoparticles showed significantly enhanced two-photon excitation singlet oxygen generation efficiency and two-photon photodynamic therapy activity in cancer cells. These composite nanoparticles display features required for ideal photosensitizers, such as low cytotoxicity in the dark and efficient two-photon photodynamic activity under laser radiation. In addition, these novel nano-photosensitizers allow simultaneous in vivo monitoring by two-photon fluorescence imaging during two-photon photodynamic treatment. These photosensitizer-doped conjugated polymer nanoparticles can act as novel photosensitizing agents for two-photon photodynamic therapy and related applications.Photosensitizer doped conjugated polymer nanoparticles have been prepared by incorporating polyoxyethylene nonylphenylether (CO-520) into the nanoparticles using a re-precipitation method. The conjugated polymer, poly[9,9-dibromohexylfluorene-2,7-ylenethylene-alt-1,4-(2,5-dimethoxy)phenylene] (PFEMO), was used as the host matrix to disperse tetraphenylporphyrin (TPP) and an energy donor to enhance the two-photon excitation properties of TPP. These CO-520 incorporated, TPP-doped PFEMO nanoparticles are stable and have low cytotoxicity in the dark. The TPP emission of the nanoparticles was found to be enhanced by about 20 times by PFEMO under two-photon excitation. The nanoparticles showed significantly enhanced two-photon excitation singlet oxygen generation efficiency and two-photon photodynamic therapy activity in cancer cells. These composite nanoparticles display features required for ideal photosensitizers, such as low cytotoxicity in the dark and efficient two-photon photodynamic activity under laser radiation. In addition, these novel nano-photosensitizers allow simultaneous in vivo monitoring by two-photon fluorescence imaging during two-photon photodynamic treatment. These photosensitizer-doped conjugated polymer nanoparticles can act as novel photosensitizing agents for two-photon photodynamic therapy and related applications. Electronic supplementary information (ESI) available: Size distribution measured by DLS and cell viability data of the non-modified conjugated polymer nanoparticles. See DOI: 10.1039/c1nr11104c

  14. Novel pentablock copolymer (PLA-PCL-PEG-PCL-PLA) based nanoparticles for controlled drug delivery: Effect of copolymer compositions on the crystallinity of copolymers and in vitro drug release profile from nanoparticles

    PubMed Central

    Tamboli, Viral; Mishra, Gyan P.; Mitra, Ashim K.

    2012-01-01

    The purpose of this investigation was to design novel pentablock copolymers (polylatide-polycaprolactone-polyethylene glycol- polycaprolactone-polylatide) (PLA-PCL-PEG-PCL-PLA) to prepare nanoparticle formulations which provide continuous delivery of steroids over a longer duration with minimal burst effect. Another purpose was to evaluate the effect of poly (L-lactide) (PLLA) or poly (D, L-lactide) (PDLLA) incorporation on crystallinity of pentablock copolymers and in vitro release profile of triamcinolone acetonide (selected as model drug) from nanoparticles. PLA-PCL-PEG-PCL-PLA copolymers with different block ratio of PCL/PLA segment were synthesized. Release of triamcinolone acetonide from nanoparticles was significantly affected by crystallinity of the copolymers. Burst release of triamcinolone acetonide from nanoparticles was significantly minimized with incorporation of proper ratio of PDLLA in the existing triblock (PCL-PEG-PCL) copolymer. Moreover, pentablock copolymer based nanoparticles exhibited continuous release of triamcinolone acetonide. Pentablock copolymer based nanoparticles can be utilized to achieve continuous near zero-order delivery of corticosteroids from nanoparticles without any burst effect. PMID:23626400

  15. Fabricated nanoparticles: current status and potential phytotoxic threats.

    PubMed

    Yadav, Tushar; Mungray, Alka A; Mungray, Arvind K

    2014-01-01

    Nanotechnology offers unique attributes to various industrial and consumer sectors, and has become a topic of high interest to scientific communities across the world. Our society has greatly benefitted from nanotechnology already, in that many products with novel properties and wide applicability have been developed and commercialized. However, the increased production and use of nanomaterials have raised concerns about the environmental fate and toxicological implications of nanoparticles and nanomaterials. Research has revealed that various nanomaterials may be hazardous to living organisms. Among biota, plants are widely exposed to released nanomaterials and are sensitive to their effects. The accumulation of nannmaterials in the environment is a potential threat, not only because of potential damage to plants hut also because nanoparticles may enter the food chain. Although the literature that addresses the safety of nanoproducts is growing, little is known about the mechanisms by which these materials produce toxicity on natural species, including humans. In this paper, we have reviewed the literature relevant to what phytotoxic impact fabricated nanoparticles (e.g., carbon nanotubes, metallic and metal oxide nanoparticles, and certain other nanomaterials) have on plants. Nanoparticles produce several effects on plant physiology and morphology. Nanoparticles are known to affect root structure, seed germination, and cellular metabolism. Nanoparticles inhibit growth, induce oxidative stress, morphogenetic abnormalities and produce clastogenic disturbances in several plant species. The size, shape and surface coating of NPs play an important role in determining their level of toxicity. Of course, the dose, route of administration, type of dispersion media, and environmental exposure also contribute to how toxic nanoparticles are to plants. Currently, nanotoxicity studies are only in their initial phases of development and more research will be required to identify the actual threat nanoproducts pose to the plant system. To date, data show that there is a large variation in the phytotoxicity caused by different NPs. Moreover, the studies conducted thus far have mostly relied on microscopy to detect effects. Studies that incorporate measures and analyses undertaken with more modern tools are needed. Among new data that are most urgently needed on NPs is how fabricated NPs behave once released into the environment, and how exposure to them may affect plant resistance, metabolic pathways, and plant genetic responses. In this review, we have attempted to collect, present and summarize recent findings from the literature on nanoparticle toxicity in plants. To strengthen the analysis, we propose a scheme for accessing NP toxicity. We also recommend how the potential challenges presented by increased production and release of NPs should be addressed. It is our belief and recommendation that every nanomaterial-based product be subjected to appropriate toxicity and associated assessment before being commercialized. PMID:24609519

  16. Nanoparticle assemblies as memristors.

    PubMed

    Kim, Tae Hee; Jang, Eun Young; Lee, Nyun Jong; Choi, Deung Jang; Lee, Kyung-Jin; Jang, Jung-tak; Choi, Jin-sil; Moon, Seung Ho; Cheon, Jinwoo

    2009-06-01

    Recently a memristor ( Chua, L. O. IEEE Trans. Circuit Theory 1971 , 18 , 507 ), the fourth fundamental passive circuit element, has been demonstrated as thin film device operations ( Strukov, D. B.; Snider, G. S.; Stewart, D. R.; Williams, R. S. Nature (London) 2008 , 453 , 80 ; Yang, J. J.; Pickett. M. D.; Li, X.; Ohlberg, D. A. A.; Stewart, D. R.; Williams, R. S. Nat. Nanotechnol. 2008 , 3 , 429 ). A new addition to the memristor family can be nanoparticle assemblies consisting of an infinite number of monodispersed, crystalline magnetite (Fe(3)O(4)) particles. Assembly of nanoparticles that have sizes below 10 nm, exhibits at room temperature a voltage-current hysteresis with an abrupt and large bipolar resistance switching (R(OFF)/R(ON) approximately 20). Interestingly, observed behavior could be interpreted by adopting an extended memristor model that combines both a time-dependent resistance and a time-dependent capacitance. We also observed that such behavior is not restricted to magnetites; it is a general property of nanoparticle assemblies as it was consistently observed in different types of spinel structured nanoparticles with different sizes and compositions. Further investigation into this new nanoassembly system will be of importance to the realization of the next generation nanodevices with potential advantages of simpler and inexpensive device fabrications. PMID:19408928

  17. Solid Lipid Nanoparticles

    Microsoft Academic Search

    Anne Saupe; Thomas Rades

    In the last decade of the last century, solid lipid nanoparticles (SLN) have been introduced to the literature as a novel carrier system for cosmetic active ingredients and pharmaceutical drugs. SLN consist of biodegradable physiological lipids or lipidic substances and stabilisers which are generally recognised as safe (GRAS) or have a regulatory accepted status. Compared to other delivery systems such

  18. Nanoparticles in forensic science

    NASA Astrophysics Data System (ADS)

    Cantu, Antonio A.

    2008-10-01

    Nanoparticles appear in several areas of forensic science including security documents, paints, inks, and reagents that develop latent prints. One reagent (known as the silver physical developer) that visualizes the water insoluble components of latent print residue is based on the formation of highly charged silver nanoparticles. These attach to and grow on the residue and generate a silver image. Another such reagent involves highly charged gold nanoparticles. These attach to the residue forming a weak gold image which can be amplified with a silver physical developer. Nanoparaticles are also used in items such as paints, printing inks, and writing inks. Paints and most printing inks consist of nano-sized pigments in a vehicle. However, certain modern ink jet printing inks now contain nano-sized pigments to improve their light fastness and most gel inks are also based on nano scale pigments. These nanoparticlecontaining materials often appear as evidence and are thus subject to forensic characterization. Both luminescent (quantum dots), up-converting nano scale phosphors, and non luminescent nanoparticles are used as security tags to label product, add security to documents, and as anti counterfeiting measures. These assist in determining if an item is fraudulently made.

  19. Nanoparticles & Quantum Dots

    E-print Network

    Strathclyde, University of

    Nanoparticles & Quantum Dots in the SEM Paul Edwards & Robert Martin #12;Outline & Acknowledgments, David Flint & Nial Wheate (SIPBS); David Stirling (UWS) · Gold nanorods Yinan Zhang & Yu Chen (Physics Society: S.Brown, P.Nativo, J.-A.Smith, D.Stirling, P.R.Edwards, D.J.Flint, D.Graham & N

  20. Nanoparticles as biochemical sensors

    PubMed Central

    El-Ansary, Afaf; Faddah, Layla M

    2010-01-01

    There is little doubt that nanoparticles offer real and new opportunities in many fields, such as biomedicine and materials science. Such particles are small enough to enter almost all areas of the body, including cells and organelles, potentially leading to new approaches in nanomedicine. Sensors for small molecules of biochemical interest are of critical importance. This review is an attempt to trace the use of nanomaterials in biochemical sensor design. The possibility of using nanoparticles functionalized with antibodies as markers for proteins will be elucidated. Moreover, capabilities and applications for nanoparticles based on gold, silver, magnetic, and semiconductor materials (quantum dots), used in optical (absorbance, luminescence, surface enhanced Raman spectroscopy, surface plasmon resonance), electrochemical, and mass-sensitive sensors will be highlighted. The unique ability of nanosensors to improve the analysis of biochemical fluids is discussed either through considering the use of nanoparticles for in vitro molecular diagnosis, or in the biological/biochemical analysis for in vivo interaction with the human body. PMID:24198472

  1. Traveling Nanoparticles Model

    NSDL National Science Digital Library

    Dr. Neil Forbes

    2008-01-01

    This is an activity (located on page 3 of the PDF) about diffusion of small molecules across cell membranes. Learners will use gelatin to represent a cell and dye to represent molecules to model how small molecules such as nanoparticles can penetrate living environments. Relates to linked video, DragonflyTV: Nanosilver.

  2. Targeting nanoparticles to cancer

    Microsoft Academic Search

    M. Wang; M. Thanou

    2010-01-01

    Nanotechnology applications in medicine, termed as nanomedicine, have introduced a number of nanoparticles of variable chemistry and architecture for cancer imaging and treatment. Nanotechnology involves engineering multifunctional devices with dimensions at the nanoscale, similar dimensions as those of large biological vesicles or molecules in our body. These devices typically have features just tens to hundred nanometers across and they can

  3. Engineering of lipid-coated PLGA nanoparticles with a tunable payload of diagnostically active nanocrystals for medical imaging.

    PubMed

    Mieszawska, Aneta J; Gianella, Anita; Cormode, David P; Zhao, Yiming; Meijerink, Andries; Langer, Robert; Farokhzad, Omid C; Fayad, Zahi A; Mulder, Willem J M

    2012-06-14

    Polylactic-co-glycolic acid (PLGA) based nanoparticles are biocompatible and biodegradable and therefore have been extensively investigated as therapeutic carriers. Here, we engineered diagnostically active PLGA nanoparticles that incorporate high payloads of nanocrystals into their core for tunable bioimaging features. We accomplished this through esterification reactions of PLGA to generate polymers modified with nanocrystals. The PLGA nanoparticles formed from modified PLGA polymers that were functionalized with either gold nanocrystals or quantum dots exhibited favorable features for computed tomography and optical imaging, respectively. PMID:22555311

  4. Ultrastable silver nanoparticles.

    PubMed

    Desireddy, Anil; Conn, Brian E; Guo, Jingshu; Yoon, Bokwon; Barnett, Robert N; Monahan, Bradley M; Kirschbaum, Kristin; Griffith, Wendell P; Whetten, Robert L; Landman, Uzi; Bigioni, Terry P

    2013-09-19

    Noble-metal nanoparticles have had a substantial impact across a diverse range of fields, including catalysis, sensing, photochemistry, optoelectronics, energy conversion and medicine. Although silver has very desirable physical properties, good relative abundance and low cost, gold nanoparticles have been widely favoured owing to their proved stability and ease of use. Unlike gold, silver is notorious for its susceptibility to oxidation (tarnishing), which has limited the development of important silver-based nanomaterials. Despite two decades of synthetic efforts, silver nanoparticles that are inert or have long-term stability remain unrealized. Here we report a simple synthetic protocol for producing ultrastable silver nanoparticles, yielding a single-sized molecular product in very large quantities with quantitative yield and without the need for size sorting. The stability, purity and yield are substantially better than those for other metal nanoparticles, including gold, owing to an effective stabilization mechanism. The particular size and stoichiometry of the product were found to be insensitive to variations in synthesis parameters. The chemical stability and structural, electronic and optical properties can be understood using first-principles electronic structure theory based on an experimental single-crystal X-ray structure. Although several structures have been determined for protected gold nanoclusters, none has been reported so far for silver nanoparticles. The total structure of a thiolate-protected silver nanocluster reported here uncovers the unique structure of the silver thiolate protecting layer, consisting of Ag2S5 capping structures. The outstanding stability of the nanoparticle is attributed to a closed-shell 18-electron configuration with a large energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, an ultrastable 32-silver-atom excavated-dodecahedral core consisting of a hollow 12-silver-atom icosahedron encapsulated by a 20-silver-atom dodecahedron, and the choice of protective coordinating ligands. The straightforward synthesis of large quantities of pure molecular product promises to make this class of materials widely available for further research and technology development. PMID:24005327

  5. Thermoelectric Properties of Carbon nanohybrids Incorporated Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Wang, Shiren

    2015-03-01

    In this work, non-covalently functionalized graphene with fluorinated fullerene (F-C60) by ?- ? stacking was integrated into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). F-C60 as a p-type organic semiconductor with deep highest occupied molecular orbital (HOMO) level modulates the band structure of reduced graphene oxide (rGO). Altering HOMO levels of rGO has been achieved by changing the ratio between rGO and F-C60. Incorporating of rGO/F-C60 nanohybrids into highly conductivity metallic PEDOT:PSS formed Schottky barrier to selectively scatter low-energy carriers. Enhanced thermoelectric power factor of rGO/F-C60/PEDOT:PSS nanocomposites were observed with the optimized power factor of 83.2 ?W/m.K2, which is 19 times of that of the highly conductive PEDOT:PSS. Additionally, the F-C60 nanoparticles on rGO surfaces hinder thermal transport by phonon scattering, resulting in the synergistic effect on enhancing thermoelectric properties. As a result, a figure of merit (ZT) of 0.10 was achieved. NSF

  6. Nanoparticle adhesion on soft substrates

    NASA Astrophysics Data System (ADS)

    Cao, Zhen; Dobrynin, Andrey; Oyer, Andrew; Stevens, Mark

    2014-03-01

    Using combination of the molecular dynamics simulations and theoretical calculations we study adhesion of spherical and cylindrical nanoparticles on soft substrates. The nanoparticle and substrate deformations are obtained as a function of the nanoparticle and substrate crosslinking density, nanoparticle size and substrate thickness, surface energy of nanoparticles and substrate, and work of adhesion. We have showed that the classical JKR model can be applied to describe nanoparticle adhesion when deformation of both substrate and nanoparticle are small. In this so-called JKR-regime the deformations of substrates and nanoparticles are determined by balancing the elastic energy of deformed objects and work of adhesion between nanoparticle and substrate. However, in the case of soft substrates and nanoparticles when both objects undergo large deformations their equilibrium shapes are determined by balancing the surface energy and work of adhesion (the so-called wetting regime). We present a simple scaling model describing crossover between JKR and wetting regimes. The model predictions are in a very good agreement with simulation results. NSF # DMR-1004576.

  7. Highly luminescent material based on Alq3:Ag nanoparticles.

    PubMed

    Salah, Numan; Habib, Sami S; Khan, Zishan H

    2013-09-01

    Tris (8-hydroxyquinoline) aluminum (Alq3) is an organic semiconductor molecule, widely used as an electron transport layer, light emitting layer in organic light-emitting diodes and a host for fluorescent and phosphorescent dyes. In this work thin films of pure and silver (Ag), cupper (Cu), terbium (Tb) doped Alq3 nanoparticles were synthesized using the physical vapor condensation method. They were fabricated on glass substrates and characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive spectroscopy, atomic force microscope (AFM), UV-visible absorption spectra and studied for their photoluminescence (PL) properties. SEM and AFM results show spherical nanoparticles with size around 70-80 nm. These nanoparticles have almost equal sizes and a homogeneous size distribution. The maximum absorption of Alq3 nanoparticles is observed at 300 nm, while the surface plasmon resonant band of Ag doped sample appears at 450 nm. The PL emission spectra of Tb, Cu and Ag doped Alq3 nanoparticles show a single broad band at around 515 nm, which is similar to that of the pure one, but with enhanced PL intensity. The sample doped with Ag at a concentration ratio of Alq3:Ag = 1:0.8 is found to have the highest PL intensity, which is around 2 times stronger than that of the pure one. This enhancement could be attributed to the surface plasmon resonance of Ag ions that might have increased the absorption and then the quantum yield. These remarkable result suggest that Alq3 nanoparticles incorporated with Ag ions might be quite useful for future nano-optoelectronic devices. PMID:23653126

  8. Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

    PubMed

    Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

    2014-11-26

    During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields. PMID:25311392

  9. On the formation and photoluminescence of Si(1-x)Ge(x) nanoparticles.

    PubMed

    Chen, P J; Tsai, M Y; Chi, C C; Perng, T P

    2007-09-01

    Si(1-x)Ge(x) nanoparticles were prepared from two annealed alloy ingots at the compositions of Si:Ge = 9.5:0.5 and 9:1 using a vapor condensation technique under Ar atmosphere. These nanoparticles are all spherical, and increasing the working pressure leads to an increased particle size and size dispersion. Comparing to the alloy ingots, the nanoparticles have a higher average content of Ge. In addition, increasing the working pressure also causes the Si(1-x)Ge(x) nanoparticles to become more Ge-rich. This can be ascribed to the lower melting point and higher kinetic energy of Ge than Si during the evaporation process. The photoluminescence of Si(1-x)Ge(x) nanoparticles ranges from visible light to infrared region, and the luminescence peak exhibits a red shift as the Ge content in the nanoparticles increases. This indicates that the incorporation of Ge into Si has a dominant effect in the radiative recombination process, in comparison with the constant luminescence peak position in the case of pure Si nanoparticles with similar size distribution. PMID:18019172

  10. Aluminum nanoparticle/acrylate copolymer nanocomposites for dielectric elastomers with high dielectric constants

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Zhang, Suki N.; Niu, Xiaofan; Liu, Chao; Pei, Qibing

    2014-03-01

    Dielectric elastomers are useful for large-strain actuation and energy harvesting. Their application has been limited by their low dielectric constants and consequently high driving voltage. Various fillers with high dielectric constants have been incorporated into different elastomer systems to improve the actuation strain, force output and energy density of the compliant actuators and generators. However, agglomeration may happen in these nanocomposites, resulting in a decrease of dielectric strength, an increase of leakage current, and in many instances the degree of enhancement of the dielectric constant. In this work, we investigated aluminum nanoparticles as nanofillers for acrylate copolymers. This metallic nanoparticle was chosen because the availability of free electrons could potentially provide an infinite value of dielectric constant as opposed to dielectric materials including ferroelectric nanocrystals. Moreover, aluminum nanoparticles have a self-passivated oxide shell effectively preventing the formation of conductive path. The surfaces of the aluminum nanoparticles were functionalized with methacrylate groups to assist the uniform dispersion in organic solutions and additionally enable copolymerization with acrylate copolymer matrix during bulk polymerization, and thus to suppress large range drifting of the nanoparticles. The resulting Al nanoparticle-acrylate copolymer nanocomposites were found to exhibit higher dielectric constant and increased stiffness. The leakage current under high electric fields were significantly lower than nanocomposites synthesized without proper nanoparticle surface modification. The dielectric strengths of the composites were comparable with the pristine polymers. In dielectric actuation evaluation, the actuation force output and energy specific work density were enhanced in the nanocomposites compared to the pristine copolymer.

  11. Nanoparticles as structural and functional units in surface-confined architectures.

    PubMed

    Shipway, A N; Willner, I

    2001-10-21

    The nanoscale engineering of functional chemical assemblies has attracted recent research effort to provide dense information storage, miniaturized sensors, efficient energy conversion, light-harvesting, and mechanical motion. Functional nanoparticles exhibiting unique photonic, electronic and catalytic properties provide invaluable building blocks for such nanoengineered architectures. Metal nanoparticle arrays crosslinked by molecular receptor units on electrodes act as selective sensing interfaces with controlled porosity and tunable sensitivity. Photosensitizer/electron-acceptor bridged arrays of Au-nanoparticles on conductive supports act as photoelectrochemically active electrodes. Semiconductor nanoparticle composites on surfaces act as efficient light collecting systems, and nanoengineered semiconductor 'core-shell' nanocrystal assemblies reveal enhanced photoelectrochemical performance due to effective charge separation. Layered metal and semiconductor nanoparticle arrays crosslinked by nucleic acids find applications in the optical, electronic and photoelectrochemical detection of DNA. Metal and semiconductor nanoparticles assembled on DNA templates may be used to generate complex electronic circuitry. Nanoparticles incorporated in hydrogel matrices yield new composite materials with novel magnetic, optical and electronic properties. PMID:12240156

  12. Novel docetaxel-loaded nanoparticles based on PCL-Tween 80 copolymer for cancer treatment

    PubMed Central

    Ma, Yuandong; Zheng, Yi; Zeng, Xiaowei; Jiang, Liqin; Chen, Hongbo; Liu, Ranyi; Huang, Laiqiang; Mei, Lin

    2011-01-01

    Background The formulation of docetaxel available for clinical use (Taxotere®) contains a high concentration of polysorbate 80 (Tween 80). After incorporation of Tween 80 into poly-?-caprolactone (PCL)-Tween 80 copolymer, the relative amount of Tween 80 should be decreased and the advantages of PCL and Tween 80 should be combined. Methods A novel PCL-Tween 80 copolymer was synthesized from ?-caprolactone and Tween 80 in the presence of stannous octoate as a catalyst via ring opening polymerization. Two types of nanoparticle formulation were made from commercial PCL and a self-synthesized PCL-Tween 80 copolymer using a modified solvent extraction/evaporation method. Results The nanoparticles were found by field emission scanning electron microscopy to have a spherical shape and be 200 nm in diameter. The copolymers could encapsulate 10% of the drug in the nanoparticles and release 34.9% of the encapsulated drug over 28 days. PCL-Tween 80 nanoparticles could be internalized into the cells and had higher cellular uptake than the PCL nanoparticles. The drug-loaded PCL-Tween 80 nanoparticles showed better in vitro cytotoxicity towards C6 cancer cells than commercial Taxotere at the same drug concentration. Conclusion Nanoparticles using PCL-Tween 80 copolymer as drug delivery vehicles may have a promising outcome for cancer patients. PMID:22114498

  13. Nanoparticles laden in situ gel of levofloxacin for enhanced ocular retention.

    PubMed

    Gupta, Himanshu; Aqil, M; Khar, R K; Ali, Asgar; Bhatnagar, Aseem; Mittal, Gaurav

    2013-01-01

    Availability of proper concentration of medicament on to the corneal surface is a challenging task. Many novel formulations, i.e. hydrogels, nanoparticles, ocuserts, etc. had been tested to improve ocular bioavailability, out of which our group found, in situ gel and polymeric nanoparticle are the most interesting approach to achieve ocular retention. We found that in situ gel stay only for 12?h and poly(lactic-co-glycolic acid (PLGA) nanoparticles are non mucoadhesive in nature so we try to combine both these formulations and termed it as "Nanoparticle laden in situ gel". Here we prepare nanoparticle laden in situ gel containing levofloxacin encapsulated PLGA nanoparticle, incorporated in chitosan in situ gel and evaluated its ocular retention by gamma scintigraphy in rabbits. The observations of acquired gamma camera images showed good retention over the entire precorneal area. From static and dynamic gamma scintigraphy evaluation, we can be interpret that developed nanoparticle laden in situ gel formulation cleared at a very slow rate and remained at corneal surface for longer duration than marketed formulation, in situ gel and nanosuspension alone. PMID:24044648

  14. Pegylated siRNA-loaded calcium phosphate nanoparticle-driven amplification of cancer cell internalization in vivo

    PubMed Central

    Tobin, Lisa A.; Xie, Yili; Tsokos, Maria; Chung, Su I.; Merz, Allison A.; Arnold, Michael A.; Li, Guang; Malech, Harry L.; Kwong, King F.

    2013-01-01

    The cell membrane is a critical barrier to effective delivery for many therapeutics, including those which are nanoparticle-based. Improving nanoparticle transport across the cell membrane remains a fundamental challenge. Cancer cells preferentially internalized pegylated calcium phosphate nanoparticles over normal epithelial cells. Furthermore, non-cytotoxic levels of doxorubicin markedly amplified this difference by increasing free unbound caveolin-1 and resulted in enhanced caveolin-mediated nanoparticle endocytosis in cancer cells. Engineered pegylated siRNA-loaded triple-shell calcium phosphate nanoconstructs incorporating ultra-low levels of doxorubicin recapitulated these effects and delivered increased numbers of siRNA into cancer cells with target-specific results. Systemic administration of nanoparticles in vivo demonstrated highly preferential entry into tumors, little bystander organ biodistribution, and significant tumor growth arrest. In conclusion, siRNA-loaded calcium phosphate nanoparticles incorporating non-cytotoxic amounts of doxorubicin markedly enhances nanoparticle internalization and results in increased payload delivery with concomitant on-target effects. PMID:23369215

  15. Incorporating salinity considerations in water availability modeling 

    E-print Network

    Krishnamurthy, Ganesh

    2006-08-16

    This research focused on expanding the capabilities of the Water Rights Analysis Package (WRAP) for incorporating salinity considerations in assessments of water availability. A simulation modeling approach was used to address this issue and a...

  16. Incorporating traffic patterns to improve delivery performance

    E-print Network

    Dickinson, Melody J

    2010-01-01

    Traffic, construction and other road hazards impact the on-time performance of companies that operate delivery fleets. This study examines how incorporating traffic patterns in vehicle route development compares with ...

  17. Facile Surface Functionalization of Hydrophobic Magnetic Nanoparticles

    E-print Network

    Tan, Weihong

    Facile Surface Functionalization of Hydrophobic Magnetic Nanoparticles Yuan Liu,,§ Tao Chen hydrophobic magnetic nanoparticles (MNPs) to an aqueous phase using tetrahydrofuran, NaOH and 3 to other types of hydrophobic nanoparticles to facilitate biomedical appli- cations of nanomaterials

  18. POLYMER PROGRAM SEMINAR "Targeted polymeric nanoparticles

    E-print Network

    Alpay, S. Pamir

    POLYMER PROGRAM SEMINAR "Targeted polymeric nanoparticles: From discovery to clinical trials" Dr, IMS Room 20 A variety of organic and inorganic materials have been utilized to generate nanoparticles for drug delivery applications, including polymeric nanoparticles, dendrimers, nanoshells, liposomes

  19. Antibacterial efficacy of triclosan-incorporated polymers

    Microsoft Academic Search

    Bilgé D. Kalyon; Ugursoy Olgun

    2001-01-01

    Triclosan (2, 4, 4’-trichloro-2’-hydroxydiphenyl ether) is a broad-spectrum antimicrobial agent, routinely used in various personal care products.1 It is also incorporated into polymers through melt-mixing, with the aim of providing persistent antibacterial action on the surface of the polymer.2,3 Such triclosan-incorporated polymers can be promoted for hospital use as fabric seat covers, tables, chairs, and clothing. We assessed the antibacterial

  20. Gold nanoparticle - modified zinc oxide nanoparticles as novel photocatalytic materials

    Microsoft Academic Search

    Nayane Udawatte

    2010-01-01

    The current study entails the construction of a novel nano-composite catalyst based on ZnO and Au nanoparticles and demonstrates its distinctive photocatalytic characteristics. Monodisperse gold nanoparticles (GNPs) passivated with monolayers of tiopronin or glutathione were synthesized via facile methods, and they were assembled on ZnO nanoparticles to form the nano-catalyst. Steady state and time resolved photoluminescent studies on the nano-composite

  1. Engineering nanoparticle antitoxins utilizing aromatic interactions.

    PubMed

    Weisman, Adam; Chen, Yingyao Allie; Hoshino, Yu; Zhang, Huiting; Shea, Kenneth

    2014-09-01

    Methicillin resistant Staphylococcus aureus (MRSA) is a highly virulent bacterium capable of inflicting severe infections. This pathogen has a long history of developing resistance to antibacterial drugs, and many phenotypes are capable of disabling the host immune response by releasing peptide and protein toxins with the capacity to lyse human polymorphonuclear neutrophils. The peptide phenol-soluble modulin ?3 (PSM?3) has been identified as an important toxin released by the most virulent strains of MRSA. A library of polymer nonaparticles was synthesized by precipitation polymerization and screened for their ability to bind and neutralize this toxin. To generate high affinity, monomers were chosen to compliment the functional groups of PSM?3. Nanoparticles incorporating aromatic monomers provided a high affinity for the peptide and were effective at neutralizing its toxicity in vitro. PMID:25093686

  2. Fluorescent polyacrylamide nanoparticles for naproxen recognition.

    PubMed

    Lapresta-Fernández, Alejandro; Cywinski, Piotr J; Moro, Artur J; Mohr, Gerhard J

    2009-11-01

    We present the synthesis of fluorescent acrylamide nanoparticles (FANs) capable of recognizing non-steroidal anti-inflammatory drugs (NSAIDs) in buffered aqueous solutions. Within this important group, we selected naproxen, one of the 2-arylpropionic acids (profens), due to its use for the treatment of moderate pain, fever, and inflammation. The nanosensors were prepared under mild conditions of inverse microemulsion polymerization using aqueous acrylamide as the monomer and N,N'-methylenebisacrylamide as the cross-linker, employing the surfactants polyoxyethylene-4-lauryl ether (Brij 30) and sodium bis(2-ethylhexyl)sulfosuccinate in hexane. Furthermore, a fluorescent monomer, (E)-4-[4-(dimethylamino)styryl]-1-[4-(methacryloyloxymethyl)benzyl]pyridinium chloride (mDMASP) has been synthesized and incorporated into the nanoparticles. The nanosensors exhibit a broad absorbance at around 460 nm and a structureless fluorescence band with maximum at 590 nm in 0.5 M phosphate buffer (pH = 7.2). The recognition process is performed on the basis of ionic interactions which are monitored by the fluorescence increase at 590 nm upon addition of different concentrations of naproxen. The FANs show a size distribution in the range of 20-80 nm, with a hydrodynamic diameter of 34 nm. In order to assess the selectivity of the FANs, a systematic study was conducted on the effect produced by drugs and biomolecules that could interfere with the analysis of naproxen. PMID:19688343

  3. Chemical synthesis of magnetic nanoparticles.

    PubMed

    Hyeon, Taeghwan

    2003-04-21

    Recent advances in the synthesis of various magnetic nanoparticles using colloidal chemical approaches are reviewed. Typically, these approaches involve either rapid injection of reagents into hot surfactant solution followed by aging at high temperature, or the mixing of reagents at a low temperature and slow heating under controlled conditions. Spherical cobalt nanoparticles with various crystal structures have been synthesized by thermally decomposing dicobalt octacarbonyl or by reducing cobalt salts. Nanoparticles of Fe-Pt and other related iron or cobalt containing alloys have been made by simultaneously reacting their constituent precursors. Many different ferrite nanoparticles have been synthesized by the thermal decomposition of organometallic precursors followed by oxidation or by low-temperature reactions inside reverse micelles. Rod-shaped iron nanoparticles have been synthesized from the oriented growth of spherical nanoparticles, and cobalt nanodisks were synthesized from the thermal decomposition of dicobalt octacarbonyl in the presence of a mixture of two surfactants. PMID:12744306

  4. Harnessing nanoparticles for immune modulation.

    PubMed

    Getts, Daniel R; Shea, Lonnie D; Miller, Stephen D; King, Nicholas J C

    2015-07-01

    Recent approaches using nanoparticles engineered for immune regulation have yielded promising results in preclinical models of disease. The number of nanoparticle therapies is growing, fueled by innovations in nanotechnology and advances in understanding of the underlying pathogenesis of immune-mediated diseases. In particular, recent mechanistic insight into the ways in which nanoparticles interact with the mononuclear phagocyte system and impact its function during homeostasis and inflammation have highlighted the potential of nanoparticle-based therapies for controlling severe inflammation while concurrently restoring peripheral immune tolerance in autoimmune disease. Here we review recent advances in nanoparticle-based approaches aimed at immune-modulation, and discuss these in the context of concepts in polymeric nanoparticle development, including particle modification, delivery and the factors associated with successful clinical deployment. PMID:26088391

  5. Performance enhancement of polymer solar cells using copper oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Wanninayake, Aruna P.; Gunashekar, Subhashini; Li, Shengyi; Church, Benjamin C.; Abu-Zahra, Nidal

    2015-06-01

    Copper oxide (CuO) is a p-type semiconductor with a band gap energy of 1.5 eV, this is close to the ideal energy gap of 1.4 eV required for solar cells to allow good solar spectral absorption. The inherent electrical characteristics of CuO nanoparticles make them attractive candidates for improving the performance of polymer solar cells when incorporated into the active polymer layer. The UV-visible absorption spectra and external quantum efficiency of P3HT/PC70BM solar cells containing different weight percentages of CuO nanoparticles showed a clear enhancement in the photo absorption of the active layer, this increased the power conversion efficiency of the solar cells by 24% in comparison to the reference cell. The short circuit current of the reference cell was found to be 5.234 mA cm?2 and it seemed to increase to 6.484 mA cm?2 in cells containing 0.6 mg of CuO NPs; in addition, the fill factor increased from 61.15% to 68.0%, showing an enhancement of 11.2%. These observations suggest that the optimum concentration of CuO nanoparticles was 0.6 mg in the active layer. These significant findings can be applied to design high-efficiency polymer solar cells containing inorganic nanoparticles.

  6. Green synthesis and applications of Au-Ag bimetallic nanoparticles.

    PubMed

    Meena Kumari, M; Jacob, John; Philip, Daizy

    2015-02-25

    This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core-shell nanostructures. The nanoparticles have been characterized using UV-vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k4-nitrophenolincorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field. PMID:25218228

  7. Green synthesis and applications of Au-Ag bimetallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Meena Kumari, M.; Jacob, John; Philip, Daizy

    2015-02-01

    This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core-shell nanostructures. The nanoparticles have been characterized using UV-vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k4-nitrophenol < k2-nitrophenol < k3-nitrophenol. Thermal conductivity is measured as a function of volume fraction and it is observed that the incorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field.

  8. Three-dimensional hydrogel constructs for exposing cells to nanoparticles.

    PubMed

    Mansfield, Elisabeth; Oreskovic, Tammy L; Rentz, Nikki S; Jeerage, Kavita M

    2014-06-01

    In evaluating nanoparticle risks to human health, there is often a disconnect between results obtained from in vitro toxicology studies and those from in vivo activity, prompting the need for improved methods to rapidly assess the hazards of engineered nanomaterials. In vitro studies of nanoparticle toxicology often rely on high doses and short exposure periods due to the difficulty of maintaining monolayer cell cultures over extended time periods as well as the difficulty of maintaining nanoparticle dispersions within the culture environment. In this work, tissue-engineered constructs are investigated as a platform for providing doses of nanoparticles over different exposure periods to cells within a three-dimensional environment that can be tuned to mimic in vivo conditions. Uptake of quantum dots (QDs) by model neural cells was first investigated in a high-dose exposure scenario, resulting in a strong concentration-dependent uptake of carboxyl-functionalised QDs. Poly(ethylene glycol) hydrogel scaffolds with varying mesh sizes were then investigated for their ability to support cell survival and proliferation. Cells were co-encapsulated with carboxyl-functionalised poly(ethylene glycol)-coated QDs at a lower dose than is typical for monolayer cultures. Although the QDs leach from the hydrogel within 24 h, they are also incorporated by cells within the scaffold, enabling the use of these constructs in future studies of cell behaviour and function. PMID:23611448

  9. Photoacoustic signal amplification through plasmonic nanoparticle aggregation

    PubMed Central

    Bayer, Carolyn L.; Nam, Seung Yun; Chen, Yun-Sheng; Emelianov, Stanislav Y.

    2013-01-01

    Abstract. Photoacoustic imaging, using targeted plasmonic metallic nanoparticles, is a promising noninvasive molecular imaging method. Analysis of the photoacoustic signal generated by plasmonic metallic nanoparticles is complex because of the dependence upon physical properties of both the nanoparticle and the surrounding environment. We studied the effect of the aggregation of gold nanoparticles on the photoacoustic signal amplitude. We found that the photoacoustic signal from aggregated silica-coated gold nanoparticles is greatly enhanced in comparison to disperse silica-coated gold nanoparticles. Because cellular uptake and endocytosis of nanoparticles results in their aggregation, these results have important implications for the application of plasmonic metallic nanoparticles towards quantitative molecular imaging. PMID:23288414

  10. Evaluation of monolayer protected metal nanoparticle technology

    E-print Network

    Wu, Diana J

    2005-01-01

    Self assembling nanostructured nanoparticles represent a new class of synthesized materials with unique functionality. Such monolayer protected metal nanoparticles are capable of resisting protein adsorption, and if utilized ...

  11. Nanoparticles for Detection and Diagnosis

    PubMed Central

    Agasti, Sarit S.; Rana, Subinoy; Park, Myoung-Hwan; Kim, Chae Kyu; You, Chang-Cheng; Rotello, Vincent M.

    2009-01-01

    Nanoparticle-based platforms for identification of chemical and biological agents offer substantial benefits to biomedical and environmental science. These platforms benefit from the availability of a wide variety of core materials as well as the unique physical and chemical properties of these nanoscale materials. This review surveys some of the emerging approaches in the field of nanoparticle based detection systems, highlighting the nanoparticle based screening methods for metal ions, proteins, nucleic acids, and biologically relevant small molecules. PMID:19913581

  12. Theranostic magnetic nanoparticles.

    PubMed

    Yoo, Dongwon; Lee, Jae-Hyun; Shin, Tae-Hyun; Cheon, Jinwoo

    2011-10-18

    Early detection and treatment of disease is the most important component of a favorable prognosis. Biomedical researchers have thus invested tremendous effort in improving imaging techniques and treatment methods. Over the past decade, concepts and tools derived from nanotechnology have been applied to overcome the problems of conventional techniques for advanced diagnosis and therapy. In particular, advances in nanoparticle technology have created new paradigms for theranostics, which is defined as the combination of therapeutic and diagnostic agents within a single platform. In this Account, we examine the potential advantages and opportunities afforded by magnetic nanoparticles as platform materials for theranostics. We begin with a brief overview of relevant magnetic parameters, such as saturation magnetization, coercivity, and magnetocrystalline anisotropy. Understanding the interplay of these parameters is critical for optimizing magnetic characteristics needed for effective imaging and therapeutics, which include magnetic resonance imaging (MRI) relaxivity, heat emission, and attractive forces. We then discuss approaches to constructing an MRI nanoparticle contrast agent with high sensitivity. We further introduce a new design concept for a fault-free contrast agent, which is a T1 and T2 dual mode hybrid. Important capabilities of magnetic nanoparticles are the external controllability of magnetic heat generation and magnetic attractive forces for the transportation and movement of biological objects. We show that these functions can be utilized not only for therapeutic hyperthermia of cancer but also for controlled release of cancer drugs through the application of an external magnetic field. Additionally, the use of magnetic nanoparticles to drive mechanical forces is demonstrated to be useful for molecular-level cell signaling and for controlling the ultimate fate of the cell. Finally, we show that targeted imaging and therapy are made possible by attaching a variety of imaging and therapeutic components. These added components include therapeutic genes (small interfering RNA, or siRNA), cancer-specific ligands, and optical reporting dyes. The wide range of accessible features of magnetic nanoparticles underscores their potential as the most promising platform material available for theranostics. PMID:21823593

  13. Some optical and catalytic properties of metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Tabor, Christopher Eugene

    Nanomaterials have been the focus of many previous publications and studies. This fact is due to the wealth of new and tunable properties that exist when a material is confined in size. This thesis discusses some of those properties pertaining to metallic nanoparticles. The primarily focus is on the plasmonic properties of gold nanoparticles with a final chapter discussing nanocatalysis and the nature of nanocatalytic reactions. The strong electromagnetic field that is induced at the surface of a plasmonic nanoparticle can be utilized for many important applications, including spectroscopic enhancements for molecular sensors and electromagnetic waveguides for sub-wavelength light manipulation. For many of these applications, it is necessary to use two or more nanoparticles in close proximity with overlapping plasmonic fields. Knowledge of how these overlapping fields are affected by the particle orientation, size, and shape is critically important, not only in understanding the fundamental properties of plasmons but also in designing future architectures that employ plasmonic particles. The field of metallic nanoparticles is introduced from its beginning, with artistic use as early as the 4th century AD through current applications and understanding. The broad spectrum of current methodologies for fabricating nanoparticles is discussed, from top down methods using lithography and from bottom up methods using metal salt reduction in solution. There are several methods used in this thesis, all of which are discussed in great detail, with some details pertaining to the specific instrumentation used here. The first study is on the transfer of surface supported gold nanoprisms from a substrate into solution using photo-thermal heating with a femtosecond pulse coincident with the plasmon resonance frequency of the nanoprisms. The mechanism of transfer is discovered to be due to super heating of solvent molecules dissolved at the particle-substrate interface. This process is studied as a function of irradiance fluence and solvent. The stability of the unprotected nanoprisms in solution is discussed. This technique has applications for creating a colloidal suspension of nanoparticle without a surfactant layer covering the surface. The particles can be chemically functionalized with any desired moiety for specific solution phase applications. The second study is on the fundamentals of plasmonic near-field coupling between two plasmonic nanoparticles as a function of the nanoparticle size, shape, and orientation. Experimental results using electron beam lithography fabricated samples are used to better understand the plasmonic coupling between dimers. Previously, the coupling between plasmonic fields around nanoparticles has been described as a near-exponential decay dependence on interparticle separation. This decay was proposed to be consistent among all sizes and shapes of nanoparticles, which was quantitatively measured using the best-fit decay length in units of the nanoparticle size. Experimental proof is presented of the shape dependence of this decay length, which is roughly 50% greater for nanoprisms than for nanodiscs, nanospheres, and nanoellipses. This was shown using simulated and experimental data. Using simulated results, the coupling decay length was shown to be independent of size for all nanoparticle shapes examined. Additionally, the effect of particle orientation on the coupling of the induced nearfields of the plasmonic particles is intensely investigated. Systematic studies using a combination of experimental samples and computer simulations are presented that examine the role of one particle's orientation to another within a plasmonic dimer system. This dependence is compared to the mathematically derived dependence and shown to be in excellent agreement. The plasmon hybridization method is given as a straightforward method to understand and predict the effect of plasmon near-field coupling on orientation. Previous methods used to understand the effect of separation on the plasmon coupling are incorporated i

  14. Multicomponent periodic nanoparticle superlattices.

    SciTech Connect

    Podsiadlo, P.; Krylova, G. V.; Demortiere, A.; Shevchenko, E. V. (Center for Nanoscale Materials)

    2011-01-01

    In this article, we review the state-of-the-art in the preparation and characterization of multicomponent self-assembled superlattices of colloidal nanoparticles with core sizes in the range of 2-20 nm and interparticle spacing less than 2 nm down to intimate contact stemming from sintering. Several aspects of the field are discussed, including: structural organization, the role of particle size distribution, key interparticle forces at play, and methods of investigation of the structures. Contrary to the extensively studied colloidal crystals composed of microscale particles, the nanoparticles possess unique size-dependent properties, such as electronic, optical, or magnetic, which when combined into periodic structures can potentially lead to new collective states stemming from precise positioning of the nanocolloids. As such, we examine a number of emerging applications of this new class of metamaterials. Finally, we speculate on the potential impact of these materials, the new directions, and the challenges for the researchers.

  15. Nanoparticle Reactions on Chip

    NASA Astrophysics Data System (ADS)

    Köhler, J. M.; Kirner, Th.; Wagner, J.; Csáki, A.; Möller, R.; Fritzsche, W.

    The handling of heterogenous systems in micro reactors is difficult due to their adhesion and transport behaviour. Therefore, the formation of precipitates and gas bubbles has to be avoided in micro reaction technology, in most cases. But, micro channels and other micro reactors offer interesting possibilities for the control of reaction conditions and transport by diffusion and convection due to the laminar flow caused by small Reynolds numbers. This can be used for the preparation and modification of objects, which are much smaller than the cross section of microchannels. The formation of colloidal solutions and the change of surface states of nano particles are two important tasks for the application of chip reactors in nanoparticle technology. Some concepts for the preparation and reaction of nanoparticles in modular chip reactor arrangements will be discussed.

  16. Metallic nanoparticles meet Metadynamics

    E-print Network

    Pavan, Luca; Baletto, Francesca

    2015-01-01

    We show how standard Metadynamics coupled with classical Molecular Dynamics can be successfully ap- plied to sample the configurational and free energy space of metallic and bimetallic nanopclusters via the implementation of collective variables related to the pair distance distribution function of the nanoparticle itself. As paradigmatic examples we show an application of our methodology to Ag147, Pt147 and their alloy AgshellPtcore at 1:1 and 2:1 chemical compositions. The proposed scheme is not only able to reproduce known structural transformation pathways, as the five and the six square-diamond mechanisms both in pure and core-shell nanoparticles but also to predict a new route connecting icosahedron to anti-cuboctahedron.

  17. Photoluminescence by Interstellar Nanoparticles

    SciTech Connect

    Witt, Adolf N. (University of Toledo) [University of Toledo

    2004-04-21

    Dust grains in interstellar space are an all-pervasive component of the Universe that affect our perception of virtually every cosmic phenomenon. They play important roles in processes like star formation, formation of molecules and formation of terrestrial planets, to name just a few. Yet, their nature, size, structure, and composition are only poorly understood. I shall report on new investigations of optical luminescence emanating from dust grains that reveal the presence of nanoparticle components of dust, most likely polycyclic aromatic hydrocarbons and tiny semiconductor nanocrystals, e.g. silicon nanoparticles. Coordinated laboratory studies of such small particles would greatly aid our efforts of arriving at definitive identifications of the luminescent astronomical dust sources.

  18. Magnetic Nanoparticle Sensors

    PubMed Central

    Koh, Isaac; Josephson, Lee

    2009-01-01

    Many types of biosensors employ magnetic nanoparticles (diameter = 5–300 nm) or magnetic particles (diameter = 300–5,000 nm) which have been surface functionalized to recognize specific molecular targets. Here we cover three types of biosensors that employ different biosensing principles, magnetic materials, and instrumentation. The first type consists of magnetic relaxation switch assay-sensors, which are based on the effects magnetic particles exert on water proton relaxation rates. The second type consists of magnetic particle relaxation sensors, which determine the relaxation of the magnetic moment within the magnetic particle. The third type is magnetoresistive sensors, which detect the presence of magnetic particles on the surface of electronic devices that are sensitive to changes in magnetic fields on their surface. Recent improvements in the design of magnetic nanoparticles (and magnetic particles), together with improvements in instrumentation, suggest that magnetic material-based biosensors may become widely used in the future. PMID:22408498

  19. Size dependent phase diagrams of Nickel-Carbon nanoparticles

    E-print Network

    Magnin, Yann; Amara, Hakim; Ducastelle, François; Bichara, Christophe

    2015-01-01

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nanometers (807 Ni atoms). A tight binding model for interatomic interactions drives the Grand Canonical Monte Carlo simulations used to locate solid, core/shell and liquid stability domains, as a function of size, temperature and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should be taken into account in our understanding of the nanotube growth mechanisms.

  20. Multispectral guided fluorescence diffuse optical tomography using upconverting nanoparticles

    SciTech Connect

    Svenmarker, Pontus, E-mail: pontus.svenmarker@physics.umu.se [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Department of Physics, Umeå University, SE-901 87 Umeå (Sweden); Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå (Sweden); Xu, Can T.; Liu, Haichun; Wu, Xia; Andersson-Engels, Stefan [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden)

    2014-02-17

    We report on improved image detectability for fluorescence diffuse optical tomography using upconverting nanoparticles doped with rare-earth elements. Core-shell NaYF{sub 4}:Yb{sup 3+}/Er{sup 3+}@NaYF{sub 4} upconverting nanoparticles were synthesized through a stoichiometric method. The Yb{sup 3+}/Er{sup 3+} sensitizer-activator pair yielded two anti-Stokes shifted fluorescence emission bands at 540?nm and 660?nm, here used to a priori estimate the fluorescence source depth with sub-millimeter precision. A spatially varying regularization incorporated the a priori fluorescence source depth estimation into the tomography reconstruction scheme. Tissue phantom experiments showed both an improved resolution and contrast in the reconstructed images as compared to not using any a priori information.

  1. Multispectral guided fluorescence diffuse optical tomography using upconverting nanoparticles

    NASA Astrophysics Data System (ADS)

    Svenmarker, Pontus; Xu, Can T.; Liu, Haichun; Wu, Xia; Andersson-Engels, Stefan

    2014-02-01

    We report on improved image detectability for fluorescence diffuse optical tomography using upconverting nanoparticles doped with rare-earth elements. Core-shell NaYF4:Yb3+/Er3+@NaYF4 upconverting nanoparticles were synthesized through a stoichiometric method. The Yb3+/Er3+ sensitizer-activator pair yielded two anti-Stokes shifted fluorescence emission bands at 540 nm and 660 nm, here used to a priori estimate the fluorescence source depth with sub-millimeter precision. A spatially varying regularization incorporated the a priori fluorescence source depth estimation into the tomography reconstruction scheme. Tissue phantom experiments showed both an improved resolution and contrast in the reconstructed images as compared to not using any a priori information.

  2. Silver nanoparticle aided self-healing of polyelectrolyte multilayers.

    PubMed

    Huang, Xiayun; Bolen, Matthew J; Zacharia, Nicole S

    2014-06-14

    Self-healing is the ability of a material to repair mechanical damage. The lifetime of a coating or film might be lengthened with this capacity. Water enabled self-healing of polyelectrolyte multilayers has been reported, using systems that grow via the interdiffusion of polyelectrolyte chains. Due to high mobility of the polyelectrolyte chains within the assembly, it is possible for lateral diffusion to heal over scratches. The influence of metal ions and nanoparticles on this property has, however, not been previously studied. Here we demonstrate that the incorporation of silver nanoparticles reduced in situ within the branched poly(ethyleneimine)-poly(acrylic acid) polyelectrolyte multilayer structure speeds the ability of the multilayer assembly to self-heal. This enhancement of property seems to not be due to changes in mechanical properties but rather in enhanced affinity to water and plasticization that enables the film to better swell. PMID:24728290

  3. Silk fibroin nanoparticle as a novel drug delivery system.

    PubMed

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Shokrgozar, Mohammad Ali; Atyabi, Fatemeh; Hosseinkhani, Hossein

    2015-05-28

    Design and synthesis of efficient drug delivery systems are of vital importance for medicine and healthcare. Nanocarrier-based drug delivery systems, in particular nanoparticles, have generated great excitement in the field of drug delivery since they provide new opportunities to overcome the limitations of conventional delivery methods with regards to the drugs. Silk fibroin (SF) is a naturally occurring protein polymer with several unique properties that make it a suitable material for incorporation into a variety of drug delivery vehicles capable of delivering a range of therapeutic agents. SF matrices have been shown to successfully deliver anticancer drugs, small molecules, and biomolecules. This review will provide an in-depth discussion of the development of SF nanoparticle-based drug delivery systems. PMID:25797561

  4. Nanoparticles in dermatology

    Microsoft Academic Search

    Dimitrios Papakostas; Fiorenza Rancan; Wolfram Sterry; Ulrike Blume-Peytavi; Annika Vogt

    Recent advances in the field of nanotechnology have allowed the manufacturing of elaborated nanometer-sized particles for\\u000a various biomedical applications. A broad spectrum of particles, extending from various lipid nanostructures such as liposomes\\u000a and solid lipid nanoparticles, to metal, nanocrystalline and polymer particles have already been tested as drug delivery systems\\u000a in different animal models with remarkable results, promising an extensive

  5. Dispersion of TiO2 Nanoparticle Agglomerates by Pseudomonas aeruginosa? †

    PubMed Central

    Horst, Allison M.; Neal, Andrea C.; Mielke, Randall E.; Sislian, Patrick R.; Suh, Won Hyuk; Mädler, Lutz; Stucky, Galen D.; Holden, Patricia A.

    2010-01-01

    Engineered nanoparticles are increasingly incorporated into consumer products and are emerging as potential environmental contaminants. Upon environmental release, nanoparticles could inhibit bacterial processes, as evidenced by laboratory studies. Less is known regarding bacterial alteration of nanoparticles, including whether bacteria affect physical agglomeration states controlling nanoparticle settling and bioavailability. Here, the effects of an environmental strain of Pseudomonas aeruginosa on TiO2 nanoparticle agglomerates formed in aqueous media are described. Environmental scanning electron microscopy and cryogenic scanning electron microscopy visually demonstrated bacterial dispersion of large agglomerates formed in cell culture medium and in marsh water. For experiments in cell culture medium, quantitative image analysis verified that the degrees of conversion of large agglomerates into small nanoparticle-cell combinations were similar for 12-h-growth and short-term cell contact experiments. Dispersion in cell growth medium was further characterized by size fractionation: for agglomerated TiO2 suspensions in the absence of cells, 81% by mass was retained on a 5-?m-pore-size filter, compared to only 24% retained for biotic treatments. Filtrate cell and agglomerate sizes were characterized by dynamic light scattering, revealing that the average bacterial cell size increased from 1.4 ?m to 1.9 ?m because of nano-TiO2 biosorption. High-magnification scanning electron micrographs showed that P. aeruginosa dispersed TiO2 agglomerates by preferential biosorption of nanoparticles onto cell surfaces. These results suggest a novel role for bacteria in the environmental transport of engineered nanoparticles, i.e., growth-independent, bacterially mediated size and mass alterations of TiO2 nanoparticle agglomerates. PMID:20851981

  6. A Post-synthetic Modification of II–VI Nanoparticles to Create Tb3+ and Eu3+ Luminophores

    PubMed Central

    Mukherjee, Prasun; Sloan, Robin F.; Shade, Chad M.; Waldeck, David H.; Petoud, Stéphane

    2013-01-01

    We describe a novel method for creating luminescent lanthanide-containing nanoparticles in which the lanthanide cations are sensitized by the semiconductor nanoparticle’s electronic excitation. In contrast to previous strategies, this new approach creates such materials by addition of external salt to a solution of fully formed nanoparticles. We demonstrate this post-synthetic modification for the lanthanide luminescence sensitization of two visible emitting lanthanides (Ln), Tb3+ and Eu3+ ions, through ZnS nanoparticles in which the cations were added post-synthetically as external Ln(NO3)3·xH2O salt to solutions of ZnS nanoparticles. The post-synthetically treated ZnS nanoparticle systems display Tb3+ and Eu3+ luminescence intensities that are comparable to those of doped Zn(Ln)S nanoparticles, which we reported previously (J. Phys. Chem. A, 2011, 115, 4031–4041). A comparison with the synthetically doped systems is used to contrast the spatial distribution of the lanthanide ions, bulk versus surface localized. The post-synthetic strategy described in this work is fundamentally different from the synthetic incorporation (doping) approach and offers a rapid and less synthetically demanding protocol for Tb3+:ZnS and Eu3+:ZnS luminophores, thereby facilitating their use in a broad range of applications. PMID:23997842

  7. Characterization of starch nanoparticles

    NASA Astrophysics Data System (ADS)

    Szymo?ska, J.; Targosz-Korecka, M.; Krok, F.

    2009-01-01

    Nanomaterials already attract great interest because of their potential applications in technology, food science and medicine. Biomaterials are biodegradable and quite abundant in nature, so they are favoured over synthetic polymer based materials. Starch as a nontoxic, cheap and renewable raw material is particularly suitable for preparation of nanoparticles. In the paper, the structure and some physicochemical properties of potato and cassava starch particles of the size between 50 to 100 nm, obtained by mechanical treatment of native starch, were presented. We demonstrated, with the aim of the Scanning Electron Microscopy (SEM) and the non-contact Atomic Force Microscopy (nc-AFM), that the shape and dimensions of the obtained nanoparticles both potato and cassava starch fit the blocklets - previously proposed as basic structural features of native starch granules. This observation was supported by aqueous solubility and swelling power of the particles as well as their iodine binding capacity similar to those for amylopectin-type short branched polysaccharide species. Obtained results indicated that glycosidic bonds of the branch linkage points in the granule amorphous lamellae might be broken during the applied mechanical treatment. Thus the released amylopectin clusters could escape out of the granules. The starch nanoparticles, for their properties qualitatively different from those of native starch granules, could be utilized in new applications.

  8. Potassium niobate nanoscrolls incorporating rhodium hydroxide nanoparticles for photocatalytic hydrogen evolution

    E-print Network

    of corrugated sheets of edge- sharing NbO6 octahedra. In each layer, the top and bottom faces are different from ) and exfoliated.2 K4Nb6O17 loaded with interlayer Ni or Pt clusters has shown high photocatalytic activity in 300 ml of 1M HCl solution for 4 days to produce HxK4ÀxNb6O17 (x z 3); presumably the remaining K+ ions

  9. Preparation, Characterization and Tests of Incorporation in Stem Cells of Superparamagnetic Iron Oxide

    NASA Astrophysics Data System (ADS)

    Haddad, P. S.; Britos, T. N.; Li, L. M.; Li, L. D. S.

    2015-05-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been produced and used as contrast-enhancing agents in magnetic resonance imaging (MRI) for diagnostic use in a wide range of maladies including cardiovascular, neurological disorders, and cancer. The reasons why these SPIONs are attractive for medical purposes are based on their important and unique features. The large surface area of the nanoparticles and their manipulation through an external magnetic field are features that allow their use for carrying a large number of molecules such as biomolecules or drugs. In this scenario, the present work reports on the synthesis and characterization of SPIONs and in vitro MRI experiments to increase their capacity as probes for MRI applications on stem cells therapy. Initially, the SPIONs were prepared through the co-precipitation method using ferrous and ferric chlorides in acidic solution. The SPIONs were coated with two thiolmolecules such as mercaptosuccinic acid (MSA) and cysteine (Cys) (molar ratio SPIONs:ligand = 1:20), leading to the formation of a stable aqueous dispersion of thiolated nanoparticles (SH-SPIONs). The SH-SPIONs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results showed that the SH-SPIONs have a mean diameter of 14 nm and display superparamagnetic behavior at room temperature. Preliminary tests of incorporation of SH-SPIONs were evaluated stem cells. The results showed that the thiolated nanoparticles have no toxic effects for stem cells and successfully internalized and enhance the contrast in MRI.

  10. Therapy for incorporated radionuclides: scope and need

    SciTech Connect

    Smith, V.H.

    1981-03-01

    In the United States the recent termination of funding for research on therapy for incorporated radionuclides has virtually halted progress on improved or new agents and procedures for removing radioactivity from the body. Research was eliminated, but is still needed on new removal agents, improved delivery system, in vitro test systems, and the toxicology of treatments. For many radionuclides, no adequate therapy exists. The relationship between radionuclide removal and reduction in cancer risk is still unanswered. Without proper research support, needed improvements in the treatment for incorporated radionuclides in the US are uncertain.

  11. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  12. Thermal treatment of magnetite nanoparticles

    PubMed Central

    Wykowska, Urszula; Satula, Dariusz; Nordblad, Per

    2015-01-01

    Summary This paper presents the results of a thermal treatment process for magnetite nanoparticles in the temperature range of 50–500 °C. The tested magnetite nanoparticles were synthesized using three different methods that resulted in nanoparticles with different surface characteristics and crystallinity, which in turn, was reflected in their thermal durability. The particles were obtained by coprecipitation from Fe chlorides and decomposition of an Fe(acac)3 complex with and without a core–shell structure. Three types of ferrite nanoparticles were produced and their thermal stability properties were compared. In this study, two sets of unmodified magnetite nanoparticles were used where crystallinity was as determinant of the series. For the third type of particles, a Ag shell was added. By comparing the coated and uncoated particles, the influence of the metallic layer on the thermal stability of the nanoparticles was tested. Before and after heat treatment, the nanoparticles were examined using transmission electron microscopy, IR spectroscopy, differential scanning calorimetry, X-ray diffraction and Mössbauer spectroscopy. Based on the obtained results, it was observed that the fabrication methods determine, to some extent, the sensitivity of the nanoparticles to external factors. PMID:26199842

  13. Antimicrobial Properties of Silver Nanoparticles

    NSDL National Science Digital Library

    Kouadio, Carrie

    This module provides students the opportunity to "explore silver nanoparticles and their effectiveness against bacterial growth in hands-on laboratory activities." Students first make silver nanoparticles and then use them in an experiment they design. This lesson will require two or more class periods and is aimed at secondary students.The document is available to download in PDF file format.

  14. Resveratrol in Solid Lipid Nanoparticles

    Microsoft Academic Search

    Maria Eugenia Carlotti; Simona Sapino; Elena Ugazio; Marina Gallarate; Silvia Morel

    2011-01-01

    This report investigates the possibility of producing solid lipid nanoparticles as protective vehicle of resveratrol, an antioxidant characterised by a fast trans-cis isomerisation. SLN aqueous dispersions were produced by hot melt homogenisation technique and characterised. It was found that the presence of tetradecyl-?-cyclodextrin in SLN formulation induced an improvement of nanoparticle characteristics. Moreover a significant reduction in resveratrol photodegradation was

  15. Role of Nanoparticles in Photocatalysis

    Microsoft Academic Search

    D. Beydoun; R. Amal; G. Low; S. McEvoy

    1999-01-01

    The aim of this review paper is to give an overview of the development and implications of nanotechnology in photocatalysis. The topics covered include a detailed look at the unique properties of nanoparticles and their relation to photocatalytic properties. Current applications of and research into the use of nanoparticles as photocatalysts has also been reviewed. Also covered is the utilization

  16. A Method for IncorporatingA Method for Incorporating Chemical Reactions intoChemical Reactions into

    E-print Network

    Politècnica de Catalunya, Universitat

    A Method for IncorporatingA Method for Incorporating Chemical Reactions intoChemical Reactions Vilarrasa, Francesca De Gaspari, Orlando Silva, Jesús Carrera #12;Introduction "Chemical reactions" in CODE), CO3 2-, OH- 5 Chemical reactions: CaCO3(s) + H+ = Ca2+ + HCO3 - CO2(aq) = CO2(g) H+ + HCO3 - = H2

  17. Nanostructured silicon thin films deposited by PECVD in the presence of silicon nanoparticles

    SciTech Connect

    Viera, G.; Cabarrocas, P.R.; Hamma, S.; Sharma, S.N.; Costa, J.; Bertran, E.

    1997-07-01

    Nanostructured silicon thin films have been deposited by plasma enhanced chemical vapor deposition at low substrate temperature (100 C) in the presence of silicon nanoparticles. The nanostructure of the films was revealed by transmission electron microscopy, Raman spectroscopy and X-ray diffraction, which showed ordered silicon domains (1--2 nm) embedded in an amorphous silicon matrix. These ordered domains are due to the particles created in the discharge that contribute to the film growth. One consequence of the incorporation of nanoparticles is the accelerated crystallization of the nanostructured silicon thin films when compared to standard a-Si:H, as shown by the electrical characterization during the annealing.

  18. Micropatterning of Ag and Au nanoparticles by microcontact printing and block copolymer micelles.

    PubMed

    Xu, Peng; Ji, Xin; Abetz, Volker; Jiang, Shimei

    2011-02-01

    Micropatterns of gold and silver nanoparticles were successfully obtained by combining microcontact printing and poly(2-vinylpyridine)-block-poly(cyclohexyl metharylate) (P2VP-b-PCHMA) diblock copolymer micelles with metal precursors. The metal ions were incorporated into poly(2-vinylpyridine) blocks and located into the core area of micelles. Then the metal-loaded micellar solutions were used as inks which were spin coated as thin layers onto polydimethylsiloxane stamps and transferred onto the substrates by stamping. Different morphologies of micellar aggregates were formed on the substrates depending on the stamp morphologies, and single layers of nanoparticles in the micropattern were obtained by the reducing process. PMID:21456150

  19. Nanocomposite Hydrogels: 3D Polymer-Nanoparticle Synergies for On-Demand Drug Delivery.

    PubMed

    Merino, Sonia; Martín, Cristina; Kostarelos, Kostas; Prato, Maurizio; Vázquez, Ester

    2015-05-26

    Considerable progress in the synthesis and technology of hydrogels makes these materials attractive structures for designing controlled-release drug delivery systems. In particular, this review highlights the latest advances in nanocomposite hydrogels as drug delivery vehicles. The inclusion/incorporation of nanoparticles in three-dimensional polymeric structures is an innovative means for obtaining multicomponent systems with diverse functionality within a hybrid hydrogel network. Nanoparticle-hydrogel combinations add synergistic benefits to the new 3D structures. Nanogels as carriers for cancer therapy and injectable gels with improved self-healing properties have also been described as new nanocomposite systems. PMID:25938172

  20. Gold-Nanoparticle-Enhanced Cancer Photothermal Therapy

    Microsoft Academic Search

    Jing-Liang Li; Min Gu

    2010-01-01

    In this paper, progress on the gold-nanoparticle-enhanced photothermal therapy is reviewed. Size- and shape-dependent optical absorption of gold nanoparticles, the effects of various parameters on the therapeutic efficiency, and the mechanisms of gold-nanoparticle-assisted cancer therapy are discussed. Future research directions of gold-nanoparticle-assisted cancer photothermal therapy are also suggested.

  1. A simple way to prepare bismuth nanoparticles

    Microsoft Academic Search

    Yanbao Zhao; Zhijun Zhang; Hongxin Dang

    2004-01-01

    In this paper, we report a simple method to prepare bismuth nanoparticles from bulk bismuth. Bismuth nanoparticles of near spherical shape have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and other techniques. Bismuth nanoparticles have mean diameter of 40–50 nm and exhibit the same crystal structure as the bulk bismuth. The surface of bismuth nanoparticle has been

  2. Green nanoparticle production using micro reactor technology

    Microsoft Academic Search

    A. Kück; M. Steinfeldt; K. Prenzel; P. Swiderek; A. v. Gleich; J. Thöming

    2011-01-01

    The importance and potential of nanoparticles in daily life as well as in various industrial processes is becoming more predominant. Specifically, silver nanoparticles are increasingly applied, e.g. in clothes and wipes, due to their antibacterial properties. For applications in liquid phase it is advantageous to produce the nanoparticles directly in suspension. This article describes a green production of silver nanoparticles

  3. Fluorescent Magnetic Nanoparticles for Biomedical Applications

    E-print Network

    Candea, George

    Fluorescent Magnetic Nanoparticles for Biomedical Applications V.M.Dao, Dr. G. Coullerez, Dr. L, the main goal was to synthesize and to characterize novel fluorescent magnetic nanoparticles. These nanoparticles (NPs) involve superparamagnetic iron oxide nanoparticles (SPIONs), a fluorescently-labeled polymer

  4. Solventless synthesis of ruthenium nanoparticles

    NASA Astrophysics Data System (ADS)

    García-Peña, Nidia G.; Redón, Rocío; Herrera-Gomez, Alberto; Fernández-Osorio, Ana Leticia; Bravo-Sanchez, Mariela; Gomez-Sosa, Gustavo

    2015-06-01

    This paper presents a novel solventless method for the synthesis of zero-valent ruthenium nanoparticles Ru(0). The proposed method, although not entirely new in the nanomaterials world, was used for the first time to synthesize zero-valent ruthenium nanoparticles. This new approach has proved to be an environmentally friendly, clean, cheap, fast, and reproducible technique which employs low amounts of solvent. It was optimized through varying amounts of reducing salt on a determined quantity of precursor and measuring the effect of this variation on the average particle size obtained. The resulting products were fully characterized by powder XRD, TEM, HR-TEM, and XPS studies, all of which corroborated the purity of the nanoparticles achieved. In order to verify the advantages of our method over other techniques, we compared our nanoparticles with two common colloidal-synthesized ruthenium nanoparticles.

  5. Stress-Induced Nanoparticle Crystallization

    PubMed Central

    2015-01-01

    We demonstrate for the first time a new mechanical annealing method that can significantly improve the structural quality of self-assembled nanoparticle arrays by eliminating defects at room temperature. Using in situ high-pressure small-angle X-ray scattering, we show that deformation of nanoparticle assembly in the presence of gigapascal level stress rebalances interparticle forces within nanoparticle arrays and transforms the nanoparticle film from an amorphous assembly with defects into a quasi-single crystalline superstructure. Our results show that the existence of the hydrostatic pressure field makes the transformation both thermodynamically and kinetically possible/favorable, thus providing new insight for nanoparticle self-assembly and integration with enhanced mechanical performance. PMID:24829089

  6. In situ formation of antimicrobial silver nanoparticles and the impregnation of hydrophobic polycaprolactone matrix for antimicrobial medical device applications.

    PubMed

    Tran, Phong A; Hocking, Dianna M; O'Connor, Andrea J

    2015-02-01

    Bacterial infection associated with medical devices remains a challenge to modern medicine as more patients are being implanted with medical devices that provide surfaces and environment for bacteria colonization. In particular, bacteria are commonly found to adhere more preferably to hydrophobic materials and many of which are used to make medical devices. Bacteria are also becoming increasingly resistant to common antibiotic treatments as a result of misuse and abuse of antibiotics. There is an urgent need to find alternatives to antibiotics in the prevention and treatment of device-associated infections world-wide. Silver nanoparticles have emerged as a promising non-drug antimicrobial agent which has shown effectiveness against a wide range of both Gram-negative and Gram-positive pathogen. However, for silver nanoparticles to be clinically useful, they must be properly incorporated into medical device materials whose wetting properties could be detrimental to not only the incorporation of the hydrophilic Ag nanoparticles but also the release of active Ag ions. This study aimed at impregnating the hydrophobic polycaprolactone (PCL) polymer, which is a FDA-approved polymeric medical device material, with hydrophilic silver nanoparticles. Furthermore, a novel approach was employed to uniformly, incorporate silver nanoparticles into the PCL matrix in situ and to improve the release of Ag ions from the matrix so as to enhance antimicrobial efficacy. PMID:25492173

  7. Manganese incorporation into ferroelectric lead titanate

    Microsoft Academic Search

    Stanislav Stoupin

    2007-01-01

    Substitution with 3d magnetic transition elements in ABO 3 ferroelectric perovskite host media is widely utilized to produce relaxor ferroelectrics. Many resulting solid solutions exhibit magnetoelectric properties affected by concentration levels of the introduced magnetic ions. For conventional material preparation techniques such as firing of mechanically mixed oxides, incorporation is often limited by 5 mol% concentration level. Doping at higher

  8. Incorporating Fisheyeing into a Visual Programming Environment

    Microsoft Academic Search

    Wayne Citrin; Carlos Santiago

    1996-01-01

    Fisheyeing, in combination with zooming, addresses the scalability problem in visual languages by allowing the user to see a portion of a large visual program in detail while at the same time viewing the remainder of the program in somewhat less detail. We describe how fisheye views have been incorporated in the VIPR (VIsual PRogramming) environment. We begin by discussing

  9. Incorporating Technology into a Hawaiian Language Curriculum.

    ERIC Educational Resources Information Center

    Ka'awa, Makalapua; Hawkins, Emily

    This paper describes Hawaiian language courses that incorporate computer technology at the University of Hawaii at Manoa. In the past decade, enrollments in all types of Hawaiian language programs have increased rapidly. The University of Hawaii is committed to extending Hawaiian language education, especially the full development of Hawaiian…

  10. Combined cycle power plant incorporating coal gasification

    DOEpatents

    Liljedahl, Gregory N. (Tariffville, CT); Moffat, Bruce K. (Simsbury, CT)

    1981-01-01

    A combined cycle power plant incorporating a coal gasifier as the energy source. The gases leaving the coal gasifier pass through a liquid couplant heat exchanger before being used to drive a gas turbine. The exhaust gases of the gas turbine are used to generate both high pressure and low pressure steam for driving a steam turbine, before being exhausted to the atmosphere.

  11. Incorporating MIDAS Routines into PDP-6 LISP

    E-print Network

    Silver, Roland

    1967-03-01

    Some PDP6 LISP users have felt a need for a way to incorporate MIDAS subroutines into LISP. LISP has been changed to let you do this, using files found on the LISP SYSTEM microtape. You write a routine for LISP in much the ...

  12. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Abdominal Assembly; (ix) Drawing No. 175-5500 Lumbar Spine Assembly; (x) Drawing No. 175-6000 Pelvis Assembly...181 and 572.186; (ix) Drawing No. 175-5500, Lumbar Spine Assembly, incorporated by reference in §§ 572.181 and...

  13. Black Boxes, Incorporated Mohammad Mahmoody Avi Wigderson

    E-print Network

    Keinan, Alon

    Black Boxes, Incorporated Mohammad Mahmoody Avi Wigderson July 26, 2012 Abstract The term "Black Box" often refers to a device whose functionality we understand, but whose inner workings we don or access to certain information. In its most basic form, a black box (also called an oracle) encodes

  14. Cognitive Social Simulation Incorporating Cognitive Architectures

    E-print Network

    Varela, Carlos

    Cognitive Social Simulation Incorporating Cognitive Architectures Ron Sun June 15, 2007 Abstract computing, can benefit from incorporat- ing cognitive architectures, as they provide a realistic basis is a domain-generic computational cognitive model that may be used for a broad multiple-domain analysis

  15. Logical Systems Incorporated The Help Systems

    E-print Network

    Mann, Tim

    Logical Systems Incorporated The Help Systems T A B L E O F C O N T E N T S Introduction ..................................... page 2 HELP/CMD ..................................... page 3 HELPRESx ................................... page 17 #12;LDOS Help System Page 1 The LDOS HELP Systems Introduction This documentation covers all

  16. Incorporating Tutoring Principles into Interactive Knowledge Acquisition

    E-print Network

    Gil, Yolanda

    in a passive manner, and could instead be designed to incorporate the proactive capabilities that one expects and an initial implementation of an acquisition dialogue system called SLICK that represents acquisition that one would expect of a good student, and become proactive learners instead of reacting to the user

  17. Incorporating Engineering Design Challenges into STEM Courses

    ERIC Educational Resources Information Center

    Householder, Daniel L., Ed.; Hailey, Christine E., Ed.

    2012-01-01

    Successful strategies for incorporating engineering design challenges into science, technology, engineering, and mathematics (STEM) courses in American high schools are presented in this paper. The developers have taken the position that engineering design experiences should be an important component of the high school education of all American…

  18. Incorporating geostatistical constraints in nonlinear inversion problems

    Microsoft Academic Search

    T. C. Johnson; P. S. Routh; T. Clemo; W. Barrash; W. P. Clement

    2007-01-01

    In this paper we present a method of incorporating semivariogram constraints into nonlinear inversion problems. That is, we describe a method of sampling the space of inverse solutions that honor a specified semivariogram or set of semivariograms and also explain a set of state data. The approach can be considered a method of conditional simulation where model conditioning is based

  19. Incorporating geostatistical constraints in nonlinear inversion problems

    Microsoft Academic Search

    T. C. Johnson; P. S. Routh; T. Clemo; W. Barrash; W. P. Clement

    2007-01-01

    (1) In this paper we present a method of incorporating semivariogram constraints into nonlinear inversion problems. That is, we describe a method of sampling the space of inverse solutions that honor a specified semivariogram or set of semivariograms and also explain a set of state data. The approach can be considered a method of conditional simulation where model conditioning is

  20. Incorporating Learning into the Cognitive Assessment Framework

    ERIC Educational Resources Information Center

    Studer, Cassandra; Junker, Brian; Chan, Helen

    2012-01-01

    The authors aimed to incorporate learning into the cognitive assessment framework that exists for static assessment data. In order to accomplish this, they derive a common likelihood function for dynamic models and introduce Parameter Driven Process for Change + Cognitive Diagnosis Model (PDPC + CDM), a dynamic model which tracks learning…

  1. Incorporating "Lesson Study" in Teacher Preparation

    ERIC Educational Resources Information Center

    Cohan, Audrey; Honigsfeld, Andrea

    2006-01-01

    This paper describes two teacher educators' practice of incorporating "jugyoun kenkyuu"--the Japanese lesson study approach--in teacher preparation programs. To ascertain the effectiveness of using this approach in undergraduate and graduate education programs, the authors conducted a research study among 17 undergraduate students and 51 graduate…

  2. The Incorporation and Abjection of Official Knowledge

    ERIC Educational Resources Information Center

    Kearl, Benjamin Kelsey

    2012-01-01

    In this essay, the author analyzes two theoretical perspectives--incorporation and abjection--that inform official knowledge generally and high school American history textbooks specifically. While contemporary textbooks increasingly depict the experiences of historically marginalized groups such as women, African Americans, Latinos, American…

  3. Incorporating Feminism into Rehabilitation Counselor Education

    ERIC Educational Resources Information Center

    Jeon, Mookyong

    2015-01-01

    Purpose: The author describes how rehabilitation counselor educators can incorporate the feminist perspective in teaching rehabilitation counselors-in-training by exploring history, core values, and training methods of feminism. Method: Based on a literature review, the author compares philosophy and concepts of rehabilitation counseling and…

  4. INCORPORATING INORGANIC FERTILIZER INTO PERENNIAL GRASSLANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inorganic fertilizers can greatly increase forage yields where soil is deficient in essential plant nutrients; but the usual practice of surface applying fertilizers on pastures allows nutrients to be transported from fields in runoff, while much of the ammonia-N volatilizes. Incorporating fertiliz...

  5. Semiconducting compounds and devices incorporating same

    SciTech Connect

    Marks, Tobin J; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2014-06-17

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  6. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  7. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  8. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  9. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  10. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  11. Galactosylated Albumin Nanoparticles of Simvastatin

    PubMed Central

    Ganesh, Kumar; Archana, Dhyani; Preeti, Kothiyal

    2015-01-01

    The present study was an attempt to develop galactosylated albumin nanoparticles of Simvastatin for treatment of hypercholesterolemia. By developing the galactosylated nanoparticulated delivery, the required action of the drug at the target site at the liver can be provided. The advantage of targeting helps to reduce the systemic side effects that may occur due to the distribution of the drug to the other organs and thus helps in maintaining the required concentration of drug at the desired site. The galacotsylated albumin nanoparticles were prepared for the selective delivery of a Simvastatin to the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) the rate-limiting enzyme in the pathway of cholesterol biosynthesis that is particularly presents on hepatocytes. The asialoglycoprotein receptor (ASGP-R) which is particularly presents on mammalian hepatocytes can be utilize for active targeting by using its natural and synthetic ligands. By utilizing this receptors can provides a unique means for the development of liver-specific carriers, such as liposomes, recombinant lipoproteins, and polymers for drug or gene delivery to the liver, especially to hepatocytes. These receptors recognize the ligands with terminal galactose or N-acetylgalactosamine residues, and endocytose the ligands for an intracellular degradation process. The albumin nanoparticles (NPs) were prepared by using desolvation method and efficiently conjugated with galactose. Various parameters such as particle size, zeta potential, percentage entrapment efficiency and drug loading efficiency, percentage yield, in-vitro drug release were determined. The size of nanoparticles (both plain and coated NPs) was 200 and 250 nm. The zeta potential of plain nanoparticles was -3.61 and that of galactose-coated nanoparticles was 64.1. The maximum drug content was in between 79.98% to 79.8 % respectively in plain, and galactose coated nanoparticles while the maximum entrapment efficiency was 70.10% and 71.03% in plain and coated nanoparticles. It was found that coating of nanoparticles increases the size of nanoparticles. PMID:25901147

  12. Solid lipid nanoparticles and nanoemulsions containing ceramides: preparation and physicochemical characterization.

    PubMed

    Deli, Georgia; Hatziantoniou, Sophia; Nikas, Yorgos; Demetzos, Costas

    2009-01-01

    Nanoemulsions (NEs) and solid lipid nanoparticles (SLNs) are widely used colloidal carriers for bioactive compounds. They are used in therapeutic, diagnostic, and cosmetic formulations. Ceramides are main components of the stratum corneum and are essential for the efficient barrier function. Their very high lipophilicity renders them difficult to incorporate in an acceptable formulation. The aim of this work was to investigate the possibility of using the benefits of nanotechnology in the efficient topical delivery of ceramides formulated as NEs or SLNs. The physicochemical characteristics of such carriers incorporating ceramides were investigated and their stability over time was assessed. Their morphology was examined under a scanning electron microscope and the interactions of their components were studied by differential scanning calorimetry. The results showed that the nanoemulsions can incorporate a high percentage (48.4% of total lipids by weight) of ceramides giving more homogeneous particle distributions of spherical-shaped nanoparticles and they maintained their characteristics over time. On the contrary, SLNs' incorporation of ceramide higher than 10.8% of total lipids by weight led to the formation of rod-like nanoparticles deteriorating the homogeneity of the particle distribution, as depicted on the high polydispersity indexes of the corresponding formulations. The results demonstrate that NEs may be the more suitable carrier, compared to SLNs. PMID:19552579

  13. Manganese-containing Prussian blue nanoparticles for imaging of pediatric brain tumors.

    PubMed

    Dumont, Matthieu F; Yadavilli, Sridevi; Sze, Raymond W; Nazarian, Javad; Fernandes, Rohan

    2014-01-01

    Pediatric brain tumors (PBTs) are a leading cause of death in children. For an improved prognosis in patients with PBTs, there is a critical need to develop molecularly-specific imaging agents to monitor disease progression and response to treatment. In this paper, we describe manganese-containing Prussian blue nanoparticles as agents for molecular magnetic resonance imaging (MRI) and fluorescence-based imaging of PBTs. Our core-shell nanoparticles consist of a core lattice structure that incorporates and retains paramagnetic Mn(2+) ions, and generates MRI contrast (both negative and positive). The biofunctionalized shell is comprised of fluorescent avidin, which serves the dual purpose of enabling fluorescence imaging and functioning as a platform for the attachment of biotinylated ligands that target PBTs. The surfaces of our nanoparticles are modified with biotinylated antibodies targeting neuron-glial antigen 2 or biotinylated transferrin. Both neuron-glial antigen 2 and the transferrin receptor are protein markers overexpressed in PBTs. We describe the synthesis, biofunctionalization, and characterization of these multimodal nanoparticles. Further, we demonstrate the MRI and fluorescence imaging capabilities of manganese-containing Prussian blue nanoparticles in vitro. Finally, we demonstrate the potential of these nanoparticles as PBT imaging agents by measuring their organ and brain biodistribution in an orthotopic mouse model of PBTs using ex vivo fluorescence imaging. PMID:24920896

  14. Manganese-containing Prussian blue nanoparticles for imaging of pediatric brain tumors

    PubMed Central

    Dumont, Matthieu F; Yadavilli, Sridevi; Sze, Raymond W; Nazarian, Javad; Fernandes, Rohan

    2014-01-01

    Pediatric brain tumors (PBTs) are a leading cause of death in children. For an improved prognosis in patients with PBTs, there is a critical need to develop molecularly-specific imaging agents to monitor disease progression and response to treatment. In this paper, we describe manganese-containing Prussian blue nanoparticles as agents for molecular magnetic resonance imaging (MRI) and fluorescence-based imaging of PBTs. Our core-shell nanoparticles consist of a core lattice structure that incorporates and retains paramagnetic Mn2+ ions, and generates MRI contrast (both negative and positive). The biofunctionalized shell is comprised of fluorescent avidin, which serves the dual purpose of enabling fluorescence imaging and functioning as a platform for the attachment of biotinylated ligands that target PBTs. The surfaces of our nanoparticles are modified with biotinylated antibodies targeting neuron-glial antigen 2 or biotinylated transferrin. Both neuron-glial antigen 2 and the transferrin receptor are protein markers overexpressed in PBTs. We describe the synthesis, biofunctionalization, and characterization of these multimodal nanoparticles. Further, we demonstrate the MRI and fluorescence imaging capabilities of manganese-containing Prussian blue nanoparticles in vitro. Finally, we demonstrate the potential of these nanoparticles as PBT imaging agents by measuring their organ and brain biodistribution in an orthotopic mouse model of PBTs using ex vivo fluorescence imaging. PMID:24920896

  15. Magnetic and degradable polymer/bioactive glass composite nanoparticles for biomedical applications.

    PubMed

    Jayalekshmi, A C; Victor, Sunita Prem; Sharma, Chandra P

    2013-01-01

    The present study focuses on the development of a biocompatible and biodegradable iron oxide incorporated chitosan-gelatin bioglass composite nanoparticles [Fe-BG]. The developed composite nanoparticle was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermo gravimetric analysis (TG) and differential scanning calorimetry analysis (DSC). The size of the negatively charged composite nanoparticle was in the range of 43-51 nm. The in vitro analysis of the composite nanoparticles was carried out by cell aggregation, protein adsorption and haemolytic activity. The magnetic hysteresis value of the composite nanoparticle showed that it is a soft magnetic material. The presence of iron oxide in the chitosan-gelatin bioglass [BG] matrix enhances biodegradability as indicated in the TG studies. Iron-oxide in equal amount to bioglass in the polymer matrix has been obtained as the optimized system. The developed composite nanoparticle is a soft magnetic material and is suitable for the magnetic hyperthermia treatment and drug delivery. More detailed in vivo studies are needed to confirm the biodegradation profile and biological activity of the material. PMID:22809595

  16. Phosphorescent nanoparticles for quantitative measurements of oxygen profiles in vitro and in vivo

    PubMed Central

    Choi, Nak Won; Verbridge, Scott S.; Williams, Rebecca M.; Chen, Jin; Kim, Ju-Young; Schmehl, Russel; Farnum, Cornelia E.; Zipfel, Warren R.; Fischbach, Claudia; Stroock, Abraham D.

    2012-01-01

    We present the development and characterization of nanoparticles loaded with a custom phosphor; we exploit these nanoparticles to perform quantitative measurements of the concentration of oxygen within three-dimensional (3-D) tissue cultures in vitro and blood vessels in vivo. We synthesized a customized ruthenium (Ru)-phosphor and incorporated it into polymeric nanoparticles via self-assembly. We demonstrate that the encapsulated phosphor is non-toxic with and without illumination. We evaluated two distinct modes of employing the phosphorescent nanoparticles for the measurement of concentrations of oxygen: 1) in vitro, in a 3-D microfluidic tumor model via ratiometric measurements of intensity with an oxygen-insensitive fluorophore as a reference, and 2) in vivo, in mouse vasculature using measurements of phosphorescence lifetime. With both methods, we demonstrated micrometer-scale resolution and absolute calibration to the dissolved oxygen concentration. Based on the ease and customizability of the synthesis of the nanoparticles and the flexibility of their application, these oxygen-sensing polymeric nanoparticles will find a natural home in a range of biological applications, benefiting studies of physiological as well as pathological processes in which oxygen availability and concentration play a critical role. PMID:22240511

  17. Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

    PubMed Central

    Notarianni, Marco; Rintoul, Llew; Motta, Nunzio

    2014-01-01

    Summary One-dimensional single crystal incorporating functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm, respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low-temperature aqueous solution growth of ZnO nanorods do not affect or cause degradation of the nanoparticles of either inorganic or organic materials. This new growth method opens the way to a plethora of applications combining the properties of single crystal host and encapsulated nanoparticles. We perform micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod. PMID:24778975

  18. Perovskite ceramic nanoparticles in polymer composites for augmenting bone tissue regeneration.

    PubMed

    Bagchi, Amrit; Meka, Sai Rama Krishna; Rao, Badari Narayana; Chatterjee, Kaushik

    2014-12-01

    There is increasing interest in the use of nanoparticles as fillers in polymer matrices to develop biomaterials which mimic the mechanical, chemical and electrical properties of bone tissue for orthopaedic applications. The objective of this study was to prepare poly(?-caprolactone) (PCL) nanocomposites incorporating three different perovskite ceramic nanoparticles, namely, calcium titanate (CT), strontium titanate (ST) and barium titanate (BT). The tensile strength and modulus of the composites increased with the addition of nanoparticles. Scanning electron microscopy indicated that dispersion of the nanoparticles scaled with the density of the ceramics, which in turn played an important role in determining the enhancement in mechanical properties of the composite. Dielectric spectroscopy revealed improved permittivity and reduced losses in the composites when compared to neat PCL. Nanofibrous scaffolds were fabricated via electrospinning. Induction coupled plasma-optical emission spectroscopy indicated the release of small quantities of Ca(+2), Sr(+2), Ba(+2) ions from the scaffolds. Piezo-force microscopy revealed that BT nanoparticles imparted piezoelectric properties to the scaffolds. In vitro studies revealed that all composites support osteoblast proliferation. Expression of osteogenic genes was enhanced on the nanocomposites in the following order: PCL/CT > PCL/ST > PCL/BT > PCL. This study demonstrates that the use of perovskite nanoparticles could be a promising technique to engineer better polymeric scaffolds for bone tissue engineering. PMID:25379989

  19. Perovskite ceramic nanoparticles in polymer composites for augmenting bone tissue regeneration

    NASA Astrophysics Data System (ADS)

    Bagchi, Amrit; Rama Krishna Meka, Sai; Narayana Rao, Badari; Chatterjee, Kaushik

    2014-12-01

    There is increasing interest in the use of nanoparticles as fillers in polymer matrices to develop biomaterials which mimic the mechanical, chemical and electrical properties of bone tissue for orthopaedic applications. The objective of this study was to prepare poly(?-caprolactone) (PCL) nanocomposites incorporating three different perovskite ceramic nanoparticles, namely, calcium titanate (CT), strontium titanate (ST) and barium titanate (BT). The tensile strength and modulus of the composites increased with the addition of nanoparticles. Scanning electron microscopy indicated that dispersion of the nanoparticles scaled with the density of the ceramics, which in turn played an important role in determining the enhancement in mechanical properties of the composite. Dielectric spectroscopy revealed improved permittivity and reduced losses in the composites when compared to neat PCL. Nanofibrous scaffolds were fabricated via electrospinning. Induction coupled plasma-optical emission spectroscopy indicated the release of small quantities of Ca+2, Sr+2, Ba+2 ions from the scaffolds. Piezo-force microscopy revealed that BT nanoparticles imparted piezoelectric properties to the scaffolds. In vitro studies revealed that all composites support osteoblast proliferation. Expression of osteogenic genes was enhanced on the nanocomposites in the following order: PCL/CT > PCL/ST > PCL/BT > PCL. This study demonstrates that the use of perovskite nanoparticles could be a promising technique to engineer better polymeric scaffolds for bone tissue engineering.

  20. Silk fibroin nanoparticles prepared by electrospray as controlled release carriers of cisplatin.

    PubMed

    Qu, Jing; Liu, Yu; Yu, Yanni; Li, Jing; Luo, Jingwan; Li, Mingzhong

    2014-11-01

    To maintain the anti-tumor activity of cis-dichlorodiamminoplatinum (CDDP) while avoiding its cytotoxicity and negative influence on normal tissue, CDDP-loaded silk fibroin nanoparticles approximately 59 nm in diameter were successfully prepared by electrospray without using organic solvent. CDDP was incorporated into nanoparticles through metal-polymer coordination bond exchange. In vitro release tests showed that the cisplatin in the nanoparticles could be slowly and sustainably released for more than 15 days. In vitro anti-cancer experiments and intracellular Pt content testing indicated that CDDP-loaded silk fibroin nanoparticles were easily internalized by A549 lung cancer cells, transferring CDDP into cancer cells and then triggering their apoptosis. In contrast, the particles were not easily internalized by L929 mouse fibroblast cells and hence showed weaker cell growth inhibition. The CDDP-loaded silk fibroin nanoparticles showed sustained and efficient killing of tumor cells but weaker inhibition of normal cells. In general, this study provides not only a novel method for preparing CDDP-loaded silk fibroin nanoparticles but also a new carrier system for clinical therapeutic drugs against lung cancers and other tumors. PMID:25280693

  1. Glycosylated polyacrylate nanoparticles by emulsion polymerization

    PubMed Central

    Abeylath, Sampath C.; Turos, Edward

    2007-01-01

    A selection of glycosylated polyacrylate nanoparticles has been prepared by radical-initiated emulsion polymerization in aqueous media. Using ethyl acrylate as a co-monomer, carbohydrate acrylates were incorporated into the poly(ethyl acrylate) framework to give stable emulsions of glyconanoparticles with an average particle size of around 40 nm. Using this technique a variety of glyconanoparticles were prepared from 3-O-acryloyl-1,2:5,6-di-O-isopropylidene-?-D-glucofuranose, 1-O-acryloyl-2,3:5,6-di-O-isopropylidene-?-D-mannofuranose, 6-O-acryloyl-1,2:3,4-di-O-isopropylidene-?-D-galactopyranose, 2-N-acryloyl-1,3,4,6-tetra-O-acetyl-?-D-glucosamine, 5-O-acryloyl-2,3-isopropylidene-1-methoxy-?-D-ribofuranose and 4-N-acetyl-5’-O-acryloyl-2’,3’-O-isopropylidene cytidine. Scanning electron microscopy, dynamic light scattering and proton NMR analysis of the emulsions indicated essentially 100% incorporation of the carbohydrate acrylate monomer into the polymer with the exception of O-benzyl- and O-benzoyl-protected carbohydrate acrylates, which gave incomplete incorporation. Formation of larger glyconanoparticles of ~80nm with (unprotected) 3-O-acryloyl-D-glucose and 5-O-acryloyl-1-methoxy-?-D-ribofuranose revealed the influence of free hydroxyl groups in the monomer on the particle size during polymerization, a feature which is also apparently dependent on the amount of carbohydrate in the matrix. This methodology allows for a new, simple route to the synthesis of polymeric glyconanoparticles with potential applications in targeted drug delivery and materials development. PMID:18677404

  2. Computational Modeling of Silicon Nanoparticle Synthesis: II. A Two-Dimensional Bivariate Model for Silicon Nanoparticle Synthesis in a Laser-Driven Reactor Including Finite-Rate Coalescence

    Microsoft Academic Search

    Hongyi Dang; Mark T. Swihart

    2009-01-01

    In this work, a two-dimensional model was developed for silicon nanoparticle synthesis by silane thermal decomposition in a six-way cross laser-driven aerosol reactor. This two-dimensional model incorporates fluid dynamics, laser heating, gas phase and surface phase chemical reactions, and aerosol dynamics, with particle transport and evolution by convection, diffusion, thermophoresis, nucleation, surface growth, coagulation, and coalescence processes. Because of the

  3. Control Large Nanoparticle Assemblies in Suparmolecular Nanoparticle Thin Films

    NASA Astrophysics Data System (ADS)

    Huang, Jingyu; Xu, Ting

    2015-03-01

    Nanocomposites can generate new properties beyond those offered by organic and inorganic building blocks to meet the demands in functional materials. The collective properties of nanocomposite materials depend on both the nature of individual building block and their spatial arrangements. With the recent development, colloidal synthesis and surface modification methods provide inorganic nanoparticles (NPs) with various sizes, shapes, compositions and properties in a facile manner. Block copolymer-based supramolecules further provide more versatile routes to control spatial arrangement of the nanoparticles over multiple length scales. Nanoparticle size is a critical parameter determining the optical and electronic properties. However, most of studies to date focused on nanoparticle smaller than 10 nm in size. Here, our recent studies showed that the assembly of nanoparticles with size larger than 10 nm can be achieved in the supramolecular nanocomposite thin films by finely tuning the ligand-polymer interactions and the sample treatment conditions. Both the overall morphology of the nanoparticle assemblies and inter-particle distances can be readily tailored. These new results opened a viable approach to construct functional materials using nanoparticles with different quantum confinement effects.

  4. Biological nanoparticles and their influence on organisms.

    PubMed

    Stanley, Sarah

    2014-08-01

    Over millions of years, biological systems have evolved wide varieties of nanoparticles. Naturally occurring nanoparticles show great diversity: they may be intracellular or extracellular, formed of organic or inorganic materials and have wide-ranging biological roles. Despite this diversity, nanoparticles found in nature possess several characteristics that make them attractive for biomedical purposes. This review presents an overview of the most common biological nanoparticles and outlines the potential applications of natural and modified biological nanoparticles. PMID:24832077

  5. Nanoparticle enhanced ionic liquid heat transfer fluids

    DOEpatents

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Gray, Joshua R.; Garcia-Diaz, Brenda L.

    2014-08-12

    A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

  6. Application of in situ adaptive tabulation to CFD simulation of nano-particle formation by reactive precipitation

    Microsoft Academic Search

    Liguang Wang; Rodney O. Fox

    2003-01-01

    Reactive precipitation involves four fundamental processes: mixing-limited reaction, nucleation, growth, and aggregation. A novel algorithm, in situ adaptive tabulation (ISAT), has been implemented in a code for micromixing simulations, which is often applied together with computational fluid dynamics (CFD), using full probability density function (PDF) methods to incorporate these fundamental processes in the formation of nano-particles by reactive precipitation in

  7. Fast preparation of printable highly conductive polymer nanocomposites by thermal decomposition of silver carboxylate and sintering of silver nanoparticles.

    PubMed

    Zhang, Rongwei; Lin, Wei; Moon, Kyoung-sik; Wong, C P

    2010-09-01

    We show the fast preparation of printable highly conductive polymer nanocomposites for future low-cost electronics. Highly conductive polymer nanocomposites, consisting of an epoxy resin, silver flakes, and incorporated silver nanoparticles, have been prepared by fast sintering between silver flakes and the incorporated silver nanoparticles. The fast sintering is attributed to: 1) the thermal decomposition of silver carboxylate-which is present on the surface of the incorporated silver flakes-to form in situ highly reactive silver nanoparticles; 2) the surface activation of the incorporated silver nanoparticles by the removal of surface residues. As a result, polymer nanocomposites prepared at 230 °C for 5 min, at 260 °C for 10 min, and using a typical lead-free solder reflow process show electrical resistivities of 8.1×10(-5), 6.0×10(-6), and 6.3×10(-5) ? cm, respectively. The correlation between the rheological properties of the adhesive paste and the noncontact printing process has been discussed. With the optimal rheological properties, the formulated highly viscous pastes (221 mPa s at 2500 s(-1)) can be non-contact-printed into dot arrays with a radius of 130 ?m. The noncontact printable polymer nanocomposites with superior electrical conductivity and fast processing are promising for the future of printed electronics. PMID:20735013

  8. Preparation of fluorescent mesoporous hollow silica-fullerene nanoparticles via selective etching for combined chemotherapy and photodynamic therapy.

    PubMed

    Yang, Yannan; Yu, Meihua; Song, Hao; Wang, Yue; Yu, Chengzhong

    2015-07-28

    Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ?50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy. PMID:26041655

  9. Preparation and characterization of poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonate) composite thin films highly loaded with platinum nanoparticles

    Microsoft Academic Search

    Chao-Ching Chang; Ming-Tai Jiang; Chen-Liang Chang; Cheng-Lan Lin

    2011-01-01

    In this work, we propose a simple and efficient, low-temperature (?120°C) process to prepare transparent thin films of poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) loaded with high concentration (up to 22.5wt%) of platinum (Pt) nanoparticles. Firstly, an improved polyol method was modified to synthesize nano-sized (?5nm) and mono-dispersed Pt particles. These nanoparticles were incorporated into the matrix of PEDOT:PSS thin films via a spin

  10. Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

    NASA Astrophysics Data System (ADS)

    Kumar, Sachin; Chatterjee, Kaushik

    2015-01-01

    The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(?-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(?-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05060f

  11. Triggered Nanoparticles as Therapeutics

    PubMed Central

    Kim, Chang Soo; Duncan, Bradley; Creran, Brian; Rotello, Vincent M.

    2013-01-01

    Summary Drug delivery systems (DDSs) face several challenges including site-specific delivery, stability, and the programmed release of drugs. Engineered nanoparticle (NP) surfaces with responsive moieties can enhance the efficacy of DDSs for in vitro and in vivo systems. This triggering process can be achieved through both endogenous (biologically controlled release) and exogenous (external stimuli controlled release) activation. In this review, we will highlight recent examples of the use of triggered release strategies of engineered nanomaterials for in vitro and in vivo applications. PMID:24159362

  12. Antibacterial properties of nanoparticles.

    PubMed

    Hajipour, Mohammad J; Fromm, Katharina M; Ashkarran, Ali Akbar; Jimenez de Aberasturi, Dorleta; de Larramendi, Idoia Ruiz; Rojo, Teofilo; Serpooshan, Vahid; Parak, Wolfgang J; Mahmoudi, Morteza

    2012-10-01

    Antibacterial agents are very important in the textile industry, water disinfection, medicine, and food packaging. Organic compounds used for disinfection have some disadvantages, including toxicity to the human body, therefore, the interest in inorganic disinfectants such as metal oxide nanoparticles (NPs) is increasing. This review focuses on the properties and applications of inorganic nanostructured materials and their surface modifications, with good antimicrobial activity. Such improved antibacterial agents locally destroy bacteria, without being toxic to the surrounding tissue. We also provide an overview of opportunities and risks of using NPs as antibacterial agents. In particular, we discuss the role of different NP materials. PMID:22884769

  13. Precise Quantification of Nanoparticle Internalization

    PubMed Central

    Gottstein, Claudia; Wu, Guohui; Wong, Benjamin J.; Zasadzinski, Joseph Anthony

    2013-01-01

    Nanoparticles have opened new exciting avenues for both diagnostic and therapeutic applications in human disease, and targeted nanoparticles are increasingly used as specific drug delivery vehicles. The precise quantification of nanoparticle internalization is of importance to measure the impact of physical and chemical properties on the uptake of nanoparticles into target cells or into cells responsible for rapid clearance. Internalization of nanoparticles has been measured by various techniques, but comparability of data between different labs is impeded by lack of a generally accepted standardized assay. Furthermore, the distinction between associated and internalized particles has been a challenge for many years, although this distinction is critical for most research questions. Previously used methods to verify intracellular location are typically not quantitative and do not lend themselves to high throughput analysis. Here we developed a mathematical model which integrates the data from high throughput flow cytometry measurements with data from quantitative confocal microscopy. The generic method described here will be a useful tool in biomedical nanotechnology studies. The method was then applied to measure the impact of surface coatings of vesosomes on their internalization by cells of the reticuloendothelial system (RES). RES cells are responsible for rapid clearance of nanoparticles, and the resulting fast blood clearance is one of the major challenges in biomedical applications of nanoparticles. Coating of vesosomes with long chain polyethylene glycol showed a trend for lower internalization by RES cells. PMID:23706031

  14. Fabrication of pRNA nanoparticles to deliver therapeutic RNAs and bioactive compounds into tumor cells

    PubMed Central

    Shu, Yi; Shu, Dan; Haque, Farzin; Guo, Peixuan

    2013-01-01

    RNA nanotechnology is a term that refers to the design, fabrication, and utilization of nanoparticles mainly composed of ribonucleic acids via bottom-up self-assembly. The packaging RNA (pRNA) of the bacteriophage phi29 DNA packaging motor has been developed into a nano-delivery platform. This protocol describes the synthesis, assembly, and functionalization of pRNA nanoparticles based on three ‘toolkits’ derived from pRNA structural features: interlocking loops for hand-in-hand interactions, palindrome sequences for foot-to-foot interactions, and an RNA three-way junction for branch-extension. siRNAs, ribozymes, aptamers, chemical ligands, fluorophores, and other functionalities can also be fused to the pRNA prior to the assembly of the nanoparticles, so as to ensure the production of homogeneous nanoparticles and the retention of appropriate folding and function of the incorporated modules. The resulting self-assembled multivalent pRNA nanoparticles are thermodynamically and chemically stable, and they remain intact at ultra-low concentrations. Gene silencing effects are progressively enhanced with increasing number of siRNA in each pRNA nanoparticle. Systemic injection of the pRNA nanoparticles into xenograft-bearing mice has revealed strong binding to tumors without accumulation in vital organs or tissues. The pRNA-based nano-delivery scaffold paves a new way towards nanotechnological application of pRNA-based nanoparticles for disease detection and treatment. The time required for completing one round of this protocol is 3–4 weeks, including in vitro functional assays, or 2–3 months including in vivo studies. PMID:23928498

  15. Anticancer Drug-Incorporated Layered Double Hydroxide Nanohybrids and Their Enhanced Anticancer Therapeutic Efficacy in Combination Cancer Treatment

    PubMed Central

    Lee, Gyeong Jin; Kang, Joo-Hee

    2014-01-01

    Objective. Layered double hydroxide (LDH) nanoparticles have been studied as cellular delivery carriers for anionic anticancer agents. As MTX and 5-FU are clinically utilized anticancer drugs in combination therapy, we aimed to enhance the therapeutic performance with the help of LDH nanoparticles. Method. Anticancer drugs, MTX and 5-FU, and their combination, were incorporated into LDH by reconstruction method. Simply, LDHs were thermally pretreated at 400°C, and then reacted with drug solution to simultaneously form drug-incorporated LDH. Thus prepared MTX/LDH (ML), 5-FU/LDH (FL), and (MTX + 5-FU)/LDH (MFL) nanohybrids were characterized by X-ray diffractometer, scanning electron microscopy, infrared spectroscopy, thermal analysis, zeta potential measurement, dynamic light scattering, and so forth. The nanohybrids were administrated to the human cervical adenocarcinoma, HeLa cells, in concentration-dependent manner, comparing with drug itself to verify the enhanced therapeutic efficacy. Conclusion. All the nanohybrids successfully accommodated intended drug molecules in their house-of-card-like structures during reconstruction reaction. It was found that the anticancer efficacy of MFL nanohybrid was higher than other nanohybrids, free drugs, or their mixtures, which means the multidrug-incorporated LDH nanohybrids could be potential drug delivery carriers for efficient cancer treatment via combination therapy. PMID:24860812

  16. Targeting to Endothelial Cells Augments the Protective Effect of Novel Dual Bioactive Antioxidant/Anti-Inflammatory Nanoparticles

    PubMed Central

    2015-01-01

    Oxidative stress and inflammation are intertwined contributors to numerous acute vascular pathologies. A novel dual bioactive nanoparticle with antioxidant/anti-inflammatory properties was developed based on the interactions of tocopherol phosphate and the manganese porphyrin SOD mimetic, MnTMPyP. The size and drug incorporation efficiency were shown to be dependent on the amount of MnTMPyP added as well as the choice of surfactant. MnTMPyP was shown to retain its SOD-like activity while in intact particles and to release in a slow and controlled manner. Conjugation of anti-PECAM antibody to the nanoparticles provided endothelial targeting and potentiated nanoparticle-mediated suppression of inflammatory activation of these cells manifested by expression of VCAM, E-selectin, and IL-8. This nanoparticle technology may find applicability with drug combinations relevant for other pathologies. PMID:24877560

  17. Synthesis and biomedical applications of functionalized fluorescent and magnetic dual reporter nanoparticles as obtained in the miniemulsion process

    NASA Astrophysics Data System (ADS)

    Holzapfel, Verena; Lorenz, Myriam; Kilian Weiss, Clemens; Schrezenmeier, Hubert; Landfester, Katharina; Mailänder, Volker

    2006-09-01

    As superparamagnetic nanoparticles capture new applications and markets, the flexibility and modifications of these nanoparticles are increasingly important aspects. Therefore a series of magnetic polystyrene particles encapsulating magnetite nanoparticles (10-12 nm) in a hydrophobic poly(styrene-co-acrylic acid) shell was synthesized by a three-step miniemulsion process. A high amount of iron oxide was incorporated by this process (typically 30-40% (w/w)). As a second reporter, a fluorescent dye was also integrated in order to obtain 'dual reporter particles'. Finally, polymerization of the monomer styrene yielded nanoparticles in the range 45-70 nm. By copolymerization of styrene with the hydrophilic acrylic acid, the amount of carboxyl groups on the surface was varied. The characterization of the latexes included dynamic light scattering, transmission electron microscopy, surface charge and magnetic measurements. For biomedical evaluation, the nanoparticles were incubated with different cell types. The introduction of carboxyl groups on the particle surfaces enabled the uptake of nanoparticles as demonstrated by the detection of the fluorescent signal by fluorescent activated cell sorter (FACS) and laser scanning microscopy. The quantity of iron in the cells that is required for most biomedical applications (like detection by magnetic resonance imaging) has to be significantly higher, as can be achieved by the uptake of magnetite encapsulated nanoparticles functionalized only with carboxyl groups. A further increase of uptake can be accomplished by transfection agents like poly-L-lysine or other positively charged polymers. This functionality was also engrafted into the surface of the nanoparticles by covalently coupling lysine to the carboxyl groups. The amount of iron that can be transfected was even higher than with the nanoparticles with a transfection agent added and this only physically adsorbed. Furthermore, the subcellular localization of these nanoparticles was demonstrated to be clustered in endosomal compartments.

  18. Structural investigations on lipid nanoparticles containing high amounts of lecithin.

    PubMed

    Schubert, Martin Alexander; Harms, Meike; Müller-Goymann, Christel Charlotte

    2006-02-01

    Solid lipid nanoparticles (SLN), an alternative colloidal drug delivery system to polymer nanoparticles, emulsions and liposomes, possess inherent low incorporation rates resulting from the crystalline structure of the solid lipid. To increase the drug loading capacity of SLN, matrix modification by incorporation of the amphiphilic lipid lecithin within the lipid matrices has been proposed as a promising alternative. The objective of this work is to investigate the effects of the lecithin on the microstructure of matrix modified SLN. In addition, these systems were checked for the existence of aggregates like mixed micelles, liposomes, etc., which could possibly be formed by lecithin leakage into the aqueous phase during the preparation process. For this purpose, laser diffraction, photon correlation spectroscopy (PCS), small angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) were performed to investigate the structure, mobility, and molecular environment of the compounds. Lecithin incorporation within the lipid matrices resulted in a concentration dependent decrease in particle size up to a critical concentration of 30%. Lecithin incorporation up to 50% was investigated but caused no further particle size decrease. TEM revealed anisometrical and crystalline platelets of ellipsoidal to disc-like shape. Furthermore, SAXS and TEM showed no signs of lecithin and nonionic emulsifier derived aggregates in the aqueous phase. This points in agreement with NMR measurements to a strong attachment of both substances to the SLN surfaces. The proposed structure of the particles after melt emulsification consists of two different layers: a crystalline triglyceride-rich core is covered in dependence of the lecithin content either by a monomolecular or multimolecular lecithin/Solutol HS15 (SOL) layer. PMID:16298113

  19. Iron Incorporation and Post-Malaria Anaemia

    PubMed Central

    Doherty, Conor P.; Cox, Sharon E.; Fulford, Antony J.; Austin, Steven; Hilmers, David C.; Abrams, Steven A.; Prentice, Andrew M.

    2008-01-01

    Background Iron supplementation is employed to treat post-malarial anaemia in environments where iron deficiency is common. Malaria induces an intense inflammatory reaction that stalls reticulo-endothelial macrophagal iron recycling from haemolysed red blood cells and inhibits oral iron absorption, but the magnitude and duration of these effects are unclear. Methodology/Principal Findings We examined the red blood cell incorporation of oral administered stable isotopes of iron and compared incorporation between age matched 18 to 36 months old children with either anaemia post-malaria (n?=?37) or presumed iron deficiency anaemia alone (n?=?36). All children were supplemented for 30 days with 2 mg/kg elemental iron as liquid iron sulphate and administered 57Fe and 58Fe on days 1 and 15 of supplementation respectively. 57Fe and58Fe incorporation were significantly reduced (8% vs. 28%: p<0.001 and 14% vs. 26%: p?=?0.045) in the malaria vs. non-malaria groups. There was a significantly greater haemoglobin response in the malaria group at both day 15 (p?=?0.001) and 30 (p<0.000) with a regression analysis estimated greater change in haemoglobin of 7.2 g/l (s.e. 2.0) and 10.1 g/l (s.e. 2.5) respectively. Conclusion/Significance Post-malaria anaemia is associated with a better haemoglobin recovery despite a significant depressant effect on oral iron incorporation which may indicate that early erythropoetic iron need is met by iron recycling rather than oral iron. Supplemental iron administration is of questionable utility within 2 weeks of clinical malaria in children with mild or moderate anaemia. PMID:18461143

  20. Oxygen incorporation in acceptor-doped perovskites

    NASA Astrophysics Data System (ADS)

    Bévillon, Emile; Dezanneau, Guilhem; Geneste, Grégory

    2011-05-01

    Oxygen is experimentally known to be incorporated in acceptor-doped perovskites at high temperatures, leading to a hole conductivity proportional to pO21/4 and increasing with temperature [(1)/(2)O2+VO••?OOX+2h•]. Either this high-temperature incorporation is thermodynamically favored by temperature, suggesting an endothermic process (?H0 > 0), or it is exothermic. In the latter case, since it is obviously associated with a ?S0 < 0, the process should be favorable only at low temperatures, except if kinetically blocked. To examine this phenomenon, the reaction of O2 incorporation into the acceptor-doped perovskites BaSnO3 and BaZrO3, doped by trivalent dopants (Ga, Sc, In, Y), according to BaSn/Zr1-xMxO3-x/2+x/4O2?BaSn/Zr1-xMxO3, is studied by density-functional calculations for a high dopant concentration (x=0.25). In this process, the charged vacancies VO•• resulting from the charge compensation produced by doping, are filled with oxygen atoms, yielding a metallic compound with holes. It is found to be exothermic in all cases, showing that these acceptor-doped perovskites are able to incorporate oxygen at low temperatures, whereas the reaction is unfavorable above a given temperature, whose value is discussed. At any rate, it is suggested that the process is kinetically blocked at low temperatures due to very slow thermally activated vacancy diffusion. A thermochemical approach is presented that tentatively explains why the hole conductivity increases with temperature at high temperatures, although the hole concentration decreases, yielding a model compatible with experimental observations and theoretical calculations.

  1. The Incorporation of ESMF at NCEP

    NASA Astrophysics Data System (ADS)

    Iredell, M.

    2008-12-01

    The Earth System Modeling Framework (ESMF) is being incorporated in the operational prediction models at the NOAA National Weather Service's National Center for Environmental Prediction (NCEP). ESMF will be used to couple several large geophysical models together, as well as to couple the atmopheric dynamics and physical parameterization package together. In addition, the nesting of atmospheric models is being developed using ESMF. The model clock, grid, state data, and metadata are managed using ESMF.

  2. Nanoparticle optical notch filters

    NASA Astrophysics Data System (ADS)

    Kasinadhuni, Pradeep Kumar

    Developing novel light blocking products involves the design of a nanoparticle optical notch filter, working on the principle of localized surface plasmon resonance (LSPR). These light blocking products can be used in many applications. One such application is to naturally reduce migraine headaches and light sensitivity. Melanopsin ganglion cells present in the retina of the human eye, connect to the suprachiasmatic nucleus (SCN-the body's clock) in the brain, where they participate in the entrainment of the circadian rhythms. As the Melanopsin ganglion cells are involved in triggering the migraine headaches in photophobic patients, it is necessary to block the part of visible spectrum that activates these cells. It is observed from the action potential spectrum of the ganglion cells that they absorb light ranging from 450-500nm (blue-green part) of the visible spectrum with a ?max (peak sensitivity) of around 480nm (blue line). Currently prescribed for migraine patients is the FL-41 coating, which blocks a broad range of wavelengths, including wavelengths associated with melanopsin absorption. The nanoparticle optical notch filter is designed to block light only at 480nm, hence offering an effective prescription for the treatment of migraine headaches.

  3. Nanoparticles in dermatology.

    PubMed

    Papakostas, Dimitrios; Rancan, Fiorenza; Sterry, Wolfram; Blume-Peytavi, Ulrike; Vogt, Annika

    2011-10-01

    Recent advances in the field of nanotechnology have allowed the manufacturing of elaborated nanometer-sized particles for various biomedical applications. A broad spectrum of particles, extending from various lipid nanostructures such as liposomes and solid lipid nanoparticles, to metal, nanocrystalline and polymer particles have already been tested as drug delivery systems in different animal models with remarkable results, promising an extensive commercialization in the coming years. Controlled drug release to skin and skin appendages, targeting of hair follicle-specific cell populations, transcutaneous vaccination and transdermal gene therapy are only a few of these new applications. Carrier systems of the new generation take advantage of improved skin penetration properties, depot effect with sustained drug release and of surface functionalization (e.g., the binding to specific ligands) allowing specific cellular and subcellular targeting. Drug delivery to skin by means of microparticles and nanocarriers could revolutionize the treatment of several skin disorders. However, the toxicological and environmental safety of micro- and nanoparticles has to be evaluated using specific toxicological studies prior to a wider implementation of the new technology. This review aims to give an overview of the most investigated applications of transcutaneously applied particle-based formulations in the fields of cosmetics and dermatology. PMID:21837474

  4. Structural Characterization of Ceria Nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivasan, R.; Bose, A. Chandra

    2011-07-01

    Cerium oxide (Ceria) nanoparticles were successfully synthesized by hydrolysis assisted co-precipitation method. As-synthesized samples are annealed at 500 °C and 800 °C respectively. Crystalline nature of the sample is analyzed by X-ray diffraction (XRD). The morphology of all the samples is investigated by transmission electron microscope (TEM) and scanning electron microscope (SEM). The average size of the nanoparticles varies between the 8 and 20 nm. Poly crystalline natures of the nanoparticles proved by selected are electron diffraction pattern (SAED). The grain size dependent absorption is demonstrated with UV-vis spectra.

  5. Method of synthesizing tungsten nanoparticles

    DOEpatents

    Thoma, Steven G; Anderson, Travis M

    2013-02-12

    A method to synthesize tungsten nanoparticles has been developed that enables synthesis of nanometer-scale, monodisperse particles that can be stabilized only by tetrahydrofuran. The method can be used at room temperature, is scalable, and the product concentrated by standard means. Since no additives or stabilizing surfactants are required, this method is particularly well suited for producing tungsten nanoparticles for dispersion in polymers. If complete dispersion is achieved due to the size of the nanoparticles, then the optical properties of the polymer can be largely maintained.

  6. Amorphous Zn?GeO? Nanoparticles as Anodes with High Reversible Capacity and Long Cycling Life for Li-ion Batteries

    SciTech Connect

    Yi, Ran; Feng, Jinkui; Lv, Dongping; Gordin, Mikhail; Chen, Shuru; Choi, Daiwon; Wang, Donghai

    2013-07-30

    Amorphous and crystalline Zn?GeO? nanoparticles were prepared and characterized as anode materials for Li-ion batteries. A higher reversible specific capacity of 1250 mAh/g after 500 cycles and excellent rate capability were obtained for amorphous Zn?GeO? nanoparticles, compared to that of crystalline Zn?GeO? nanoparticles. Small particle size, amorphous phase and incorporation of zinc and oxygen contribute synergetically to the improved performance by effectively mitigating the huge volume variations during lithiation and delithiation process.

  7. Fluorescent Property of Gold Nanoparticles with Different Surface Structures

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-juan; Wang, Chun-xia; Wang, Yong; Niu, Shu-hua; Lü, Chang-gui; Fu, De-gang

    2007-12-01

    Fluorescence spectra of naked gold nanoparticles, triphenylphosphine stabled gold nanoparticles, and 3-mercaptopropionic acid substituted gold nanoparticles were studied. It was found that fluorescence intensities of gold nanoparticles were highly sensitive to surface molecules. The fluorescence quenching effect of these gold nanoparticles on CdSe nanoparticles was also investigated. This quenching effect was related to the overlap degree between the absorption spectra of gold nanoparticles and the emission spectrum of CdSe nanoparticles, and was surface-dependent as well.

  8. Preparation and in vitro evaluation of topical formulations based on polystyrene-poly-2-hydroxyl methacrylate nanoparticles.

    PubMed

    Wu, Xiao; Griffin, Peter; Price, Gareth J; Guy, Richard H

    2009-01-01

    The skin disposition of topically applied nanoparticles with varying degrees of hydrophobicity, composed of different proportions of polystyrene (PS) and poly-(2-hydroxyethyl methacrylate) (HEMA), and of an associated, model "active" (Nile Red), was investigated. PS-HEMA copolymer nanoparticles were fluorescently labeled, via the covalent incorporation of a small quantity of fluorescein methacrylate, and characterized by dynamic light scattering, transmission electron microscopy and NMR. The fluorophore, Nile Red, was dispersed into the nanoparticles and its loading was determined by ultracentrifugation. Skin uptake was assessed in vitro following a 6 h application of the nanoparticle formulation, via stratum corneum (SC) tape-stripping and confocal microscopy. Nanoparticle diameters were below 100 nm. Progressive introduction of HEMA decreased particle hydrophobicity and reduced Nile Red loading. Uptake of Nile Red into the skin, as assessed both by the amounts extracted from the SC and by confocal microscopy, decreased as the percentage HEMA increased. Confocal microscopy confirmed that nanoparticles could not move beyond the superficial SC, but did show affinity for hair follicle openings. In conclusion, the loading of a lipophilic "active" into nanoparticles, and its subsequent release when these formulations are applied topically, are sensitive to the composition and relative hydrophobicity of the carrier. PMID:19630401

  9. Enhanced dermal delivery of diflucortolone valerate using lecithin/chitosan nanoparticles: in-vitro and in-vivo evaluations

    PubMed Central

    Özcan, ?pek; Azizo?lu, Erkan; ?enyi?it, Taner; Özyaz?c?, Mine; Özer, Özgen

    2013-01-01

    The objective of this study was to prepare a suitable formulation for dermal delivery of diflucortolone valerate (DFV) that would maintain the localization in skin layers without any penetration and to optimize efficiency of DFV. Drug-loaded lecithin/chitosan nanoparticles with high entrapment efficiency (86.8%), were successfully prepared by ionic interaction technique. Sustained release of DFV was achieved without any initial burst release. Nanoparticles were also incorporated into chitosan gel at different ratios for preparing a more suitable formulation for topical drug delivery with adequate viscosity. In ex-vivo permeation studies, nanoparticles increased the accumulation of DFV especially in the stratum corneum + epidermis of rat skin without any significant permeation. Retention of DFV from nanoparticle in chitosan gel formulation (0.01%) was twofold higher than commercial cream, although it contained ten times less DFV. Nanoparticles in gel formulations produced significantly higher edema inhibition in rats compared with commercial cream in in-vivo studies. Skin blanching assay using a chromameter showed vasoconstriction similar to that of the commercial product. There were no barrier function changes upon application of nanoparticles. In-vitro and in-vivo results demonstrated that lecithin/chitosan nanoparticles in chitosan gel may be a promising carrier for dermal delivery of DFV in various skin disorders. PMID:23390364

  10. Colloidal gold-loaded, biodegradable, polymer-based stavudine nanoparticle uptake by macrophages: an in vitro study

    PubMed Central

    Basu, Sumit; Mukherjee, Biswajit; Chowdhury, Samrat Roy; Paul, Paramita; Choudhury, Rupak; Kumar, Ajeet; Mondal, Laboni; Hossain, Chowdhury Mobaswar; Maji, Ruma

    2012-01-01

    Objective We describe the development, evaluation, and comparison of colloidal gold-loaded, poly(d,l-lactic-co-glycolic acid)-based nanoparticles containing anti-acquired immunodeficiency syndrome drug stavudine and uptake of these nanoparticles by macrophages in vitro. Methods We used the following methods in this study: drug-excipient interaction by Fourier transform infrared spectroscopy, morphology of nanoparticles by field-emission scanning electron microscopy, particle size by a particle size analyzer, and zeta potential and polydispersity index by a zetasizer. Drug loading and in vitro release were evaluated for formulations. The best formulation was incorporated with fluorescein isothiocyanate. Macrophage uptake of fluorescein isothiocyanate nanoparticles was studied in vitro. Results Variations in process parameters, such as speed of homogenization and amount of excipients, affected drug loading and the polydispersity index. We found that the drug was released for a prolonged period (over 63 days) from the nanoparticles, and observed cellular uptake of stavudine nanoparticles by macrophages. Conclusion Experimental nanoparticles represent an interesting carrier system for the transport of stavudine to macrophages, providing reduced required drug dose and improved drug delivery to macrophages over an extended period. The presence of colloidal gold in the particles decreased the drug content and resulted in comparatively faster drug release. PMID:23271908

  11. Effect of surface charge on the colloidal stability and in vitro uptake of carboxymethyl dextran-coated iron oxide nanoparticles

    PubMed Central

    Ayala, Vanessa; Herrera, Adriana P.; Latorre-Esteves, Magda; Torres-Lugo, Madeline

    2013-01-01

    Nanoparticle physicochemical properties such as surface charge are considered to play an important role in cellular uptake and particle–cell interactions. In order to systematically evaluate the role of surface charge on the uptake of iron oxide nanoparticles, we prepared carboxymethyl-substituted dextrans with different degrees of substitution, ranging from 38 to 5 groups per chain, and reacted them using carbodiimide chemistry with amine–silane-coated iron oxide nanoparticles with narrow size distributions in the range of 33–45 nm. Surface charge of carboxymethyl-substituted dextran-coated nano-particles ranged from ?50 to 5 mV as determined by zeta potential measurements, and was dependent on the number of carboxymethyl groups incorporated in the dextran chains. Nanoparticles were incubated with CaCo-2 human colon cancer cells. Nanoparticle–cell interactions were observed by confocal laser scanning microscopy and uptake was quantified by elemental analysis using inductively coupled plasma mass spectroscopy. Mechanisms of internalization were inferred using pharmacological inhibitors for fluid-phase, clathrin-mediated, and caveola-mediated endocytosis. Results showed increased uptake for nanoparticles with greater negative charge. Internalization patterns suggest that uptake of the most negatively charged particles occurs via non-specific interactions. PMID:24470787

  12. The use of nanoparticles to deliver nitric oxide to hepatic stellate cells for treating liver fibrosis and portal hypertension.

    PubMed

    Duong, Hien T T; Dong, Zhixia; Su, Lin; Boyer, Cyrille; George, Jacob; Davis, Thomas P; Wang, Jianhua

    2015-05-01

    Polymeric nanoparticles are designed to transport and deliver nitric oxide (NO) into hepatic stellate cells (HSCs) for the potential treatment of both liver fibrosis and portal hypertension. The nanoparticles, incorporating NO donor molecules (S-nitrosoglutathione compound), are designed for liver delivery, minimizing systemic delivery of NO. The nanoparticles are decorated with vitamin A to specifically target HSCs. We demonstrate, using in vitro and in vivo experiments, that the targeted nanoparticles are taken up specifically by rat primary HSCs and the human HSC cell line accumulating in the liver. When nanoparticles, coated with vitamin A, release NO in liver cells, we find inhibition of collagen I and ?-smooth muscle actin (?-SMA), fibrogenic genes associated with activated HSCs expression in primary rat liver and human activated HSCs without any obvious cytotoxic effects. Finally, NO-releasing nanoparticles targeted with vitamin A not only attenuate endothelin-1 (ET-1) which elicites HSC contraction but also acutely alleviates haemodynamic disorders in bile duct-ligated-induced portal hypertension evidenced by decreasing portal pressure (?20%) and unchanging mean arterial pressure. This study clearly shows, for the first time, the potential for HSC targeted nanoparticle delivery of NO as a treatment for liver diseases with proven efficacy for alleviating both liver fibrosis and portal hypertension. PMID:25641921

  13. Block copolymer mediated stabilization of sub-5 nm superparamagnetic nickel nanoparticles in an aqueous medium.

    PubMed

    Bala, Tanushree; Gunning, Robert Denis; Venkatesan, Munuswamy; Godsell, Jeffrey F; Roy, Saibal; Ryan, Kevin M

    2009-10-14

    This paper presents a facile method for decreasing the size of water dispersible Ni nanoparticles from 30 to 3 nm by the incorporation of a passivating surfactant combination of pluronic triblock copolymer and oleic acid into a wet chemical reduction synthesis. A detailed study revealed that the size of the Ni nanoparticles is not only critically governed by the concentration of the triblock copolymers but also dependent on the hydrophobic nature of the micelle core formed. The synthesized Ni nanoparticles were thoroughly characterized by means of transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and temperature and field dependent magnetic measurements, along with a comprehensive Fourier transform infrared spectroscopy analysis, in order to predict a possible mechanism of formation. PMID:19762940

  14. Biocompatible Fe-Si Nanoparticles with Adjustable Self-Regulation of Temperature for Medical Applications.

    PubMed

    Jing, Ying; Liu, Jinming; Ji, Wei-Hang; Wang, Wei; He, Shi-Hai; Jiang, Xiao-Ze; Wiedmann, Timothy; Wang, Chun; Wang, Jian-Ping

    2015-06-17

    Because of the noninvasive, locally selective potential of thermal energy, considerable effort has been focused on the use of an external, alternating magnetic field for conversion of magnetic work to heat with iron oxide nanoparticles. However, proper regulation of thermal energy remains a challenge because of the lack of feedback from the local temperature change to the external power supply. Here, we show development of smart magnetic nanoparticles composed of Fe and Si with intrinsically tunable heat generation capability. They were engineered to possess an adjustable magnetic transition temperature through tuning the exchange between Fe atoms by incorporation of silicon atoms. They show relatively high magnetic moment. Moreover, their biocompatibility was established in several cell lines. The nanoparticles were also combined with a thermosensitive polymer, which had the capability to release of molecules with a magnetic stimulus, thereby providing a platform for locally controlled, drug release. PMID:25996162

  15. Effect of samarium nanoparticles on the electrical transport properties of polyaniline

    NASA Astrophysics Data System (ADS)

    Gupta, K.; Mukherjee, P. S.; Meikap, A. K.; Jana, P. C.

    2014-06-01

    A comprehensive study of the effect of samarium nanoparticles on electrical transport properties of polyaniline has been reported. Samples are prepared by chemical oxidative polymerization of aniline in the presence of samarium nanoparticles and characterized by XRD, FESEM, EDS, HRTEM and UV-Vis spectrometer. When the samarium content in polyaniline matrix increases, energy band gap decreases and conductivity increases by four orders of magnitude. A transformation of negative to positive magnetoconductivity has been observed by incorporating samarium nanoparticles in polyaniline matrix. Two types of activation behavior have been observed from the dielectric relaxation behavior. AC conductivity strongly depends on magnetic field. Although, at present, no theoretical model is found in literature to explain directly the behavior of ac conductivity in the presence of magnetic field, it may be due to the change of grain and interfacial boundary resistances by magnetic field.

  16. A slow-release system of bacterial cellulose gel and nanoparticles for hydrophobic active ingredients.

    PubMed

    Numata, Yukari; Mazzarino, Leticia; Borsali, Redouane

    2015-05-30

    A combination of bacterial cellulose (BC) gel and amphiphilic block copolymer nanoparticles was investigated as a drug delivery system (DDS) for hydrophobic active ingredients. Poly(ethylene oxide)-b-poly(caprolactone) (PEO-b-PCL) and retinol were used as the block copolymer and hydrophobic active ingredient, respectively. The BC gel was capable of incorporating copolymer nanoparticles and releasing them in an acetic acid-sodium acetate buffer solution (pH 5.2) at 37 °C. The percentage of released copolymer reached a maximum value of approximately 60% after 6h and remained constant after 24h. The percentage of retinol released from the copolymer-containing BC gel reached a maximum value at 4h. These results show that the combination of BC gel and nanoparticles is a slow-release system that may be useful in the cosmetic and biomedical fields for skin treatment and preparation. PMID:25840273

  17. Nanoparticles and metrology: a comparison of methods for the determination of particle size distributions

    NASA Astrophysics Data System (ADS)

    Coleman, Victoria A.; Jämting, Åsa K.; Catchpoole, Heather J.; Roy, Maitreyee; Herrmann, Jan

    2011-10-01

    Nanoparticles and products incorporating nanoparticles are a growing branch of nanotechnology industry. They have found a broad market, including the cosmetic, health care and energy sectors. Accurate and representative determination of particle size distributions in such products is critical at all stages of the product lifecycle, extending from quality control at point of manufacture to environmental fate at the point of disposal. Determination of particle size distributions is non-trivial, and is complicated by the fact that different techniques measure different quantities, leading to differences in the measured size distributions. In this study we use both mono- and multi-modal dispersions of nanoparticle reference materials to compare and contrast traditional and novel methods for particle size distribution determination. The methods investigated include ensemble techniques such as dynamic light scattering (DLS) and differential centrifugal sedimentation (DCS), as well as single particle techniques such as transmission electron microscopy (TEM) and microchannel resonator (ultra high-resolution mass sensor).

  18. Room temperature ammonia sensor based on copper nanoparticle intercalated polyaniline nanocomposite thin films

    NASA Astrophysics Data System (ADS)

    Patil, U. V.; Ramgir, Niranjan S.; Karmakar, N.; Bhogale, A.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K.; Kothari, D. C.

    2015-06-01

    Thin films of copper nanoparticles intercalated-polyaniline nanocomposites (NC) have been deposited at room temperatures by in situ oxidative polymerization of aniline in the presence of different concentrations of Cu nanoparticles. The response characteristics of the NC thin films toward different gases namely NH3, CO, CO2, NO and CH4 were examined at room temperature. Both pure polyaniline (PANI) and NC films exhibited a selective response toward NH3. Incorporation of Cu nanoparticles resulted in an improvement of the sensors response and response kinetics. The response and the recovery times of composite film toward 50 ppm of NH3 were 7 and 160 s, respectively. Additionally, the NC sensor film could reversibly detect as low as 1 ppm of NH3 concentrations. The enhanced response of NC films toward NH3 is attributed to the deprotonation and reprotonation processes as also supported by Raman investigations.

  19. Synthesis, structure and ferromagnetic properties of Ni-doped ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Cong, C. J.; Hong, J. H.; Liu, Q. Y.; Liao, L.; Zhang, K. L.

    2006-06-01

    Nanosized Ni-doped ZnO particles were synthesized by rheological phase reaction-precursor method and the thermal decomposition of oxalate precursors was studied by thermogravimetry and differential thermal analysis in air atmosphere. X-ray analysis reveals that the Ni-doped ZnO crystallizes in a wurtzite structure. The lattice constants of Ni-doped ZnO nanoparticles decrease slightly when Ni is doped into ZnO. HRTEM analysis indicates that the average diameter of the nanoparticles is about 10-13 nm and no secondary phase was observed with the sensitivity of XRD measurement. Furthermore, two additional Raman peaks were observed, which may be considered to have an origin related to the incorporation of Ni ions into the Zn site of the ZnO lattice. Magnetization measurements under field-cooled and zero-field-cooled conditions reveal that Ni-doped ZnO nanoparticles show ferromagnetic behaviors in room temperature.

  20. Glutathione-Coated Luminescent Gold Nanoparticles: A Surface Ligand for Minimizing Serum Protein Adsorption

    PubMed Central

    2015-01-01

    Ultrasmall glutathione-coated luminescent gold nanoparticles (GS-AuNPs) are known for their high resistance to serum protein adsorption. Our studies show that these NPs can serve as surface ligands to significantly enhance the physiological stability and lower the serum protein adsorption of superparamagnetic iron oxide nanoparticles (SPIONs), in addition to rendering the NPs the luminescence property. After the incorporation of GS-AuNPs onto the surface of SPIONs to form the hybrid nanoparticles (HBNPs), these SPIONs’ protein adsorption was about 10-fold lower than those of the pure glutathione-coated SPIONs suggesting that GS-AuNPs are capable of providing a stealth effect against serum proteins. PMID:25029478