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Sample records for lymphocyte-target cell conjugates

  1. DNA-cell conjugates

    Science.gov (United States)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  2. Paraflagellar rod protein-specific CD8+ cytotoxic T lymphocytes target Trypanosoma cruzi-infected host cells.

    Science.gov (United States)

    Wrightsman, Ruth A; Luhrs, Keith A; Fouts, David; Manning, Jerry E

    2002-08-01

    Our previous studies show that in mice immunized with the paraflagellar rod (PFR) proteins of Trypanosoma cruzi protective immunity against this protozoan parasite requires MHC class I-restricted T cell function. To determine whether PFR-specific CD8+ T cell subsets are generated during T. cruzi infection, potential CTL targets in the PFR proteins were identified by scanning the amino acid sequences of the four PFR proteins for regions of 8-10 amino acids that conform to predicted MHC class I H-2b binding motifs. A subset of the peptide sequences identified were synthesized and tested as target antigen in 51Cr-release assays with effector cells from chronically infected T. cruzi mice. Short-term cytotoxic T lymphocyte (CTL) lines specific for two of the peptides, PFR-1(164-171) and PFR-3(123-130), showed high levels of lytic activity against peptide-pulsed target cells, secreted interferon (IFN)-gamma in response to parasite-infected target cells, and were found to be CD8+, CD4-, CD3+, TCRalphabeta+ cells of the Tc1 subset. Challenge of PFR immunized CD8-/- and perforin-deficient (PKO) mice confirmed that while CD8+ cells are required for survival of T. cruzi challenge infection, perforin activity is not required. Furthermore, while lytic activity of PFR-specific CD8+ T cell lines derived from PKO mice was severely impaired, the IFN-gamma levels secreted by CTLs from PKO mice were equivalent to that of normal mice, suggesting that the critical role played by CD8+ T cells in immunity to the parasite may be secretion of type 1 cytokines rather than lysis of parasite infected host cells.

  3. Effective Cytotoxic T Lymphocyte Targeting of Persistent HIV-1 during Antiretroviral Therapy Requires Priming of Naive CD8+ T Cells

    Directory of Open Access Journals (Sweden)

    Kellie N. Smith

    2016-05-01

    Full Text Available Curing HIV-1 infection will require elimination of persistent cellular reservoirs that harbor latent virus in the face of combination antiretroviral therapy (cART. Proposed immunotherapeutic strategies to cure HIV-1 infection include enhancing lysis of these infected cells by cytotoxic T lymphocytes (CTL. A major challenge in this strategy is overcoming viral immune escape variants that have evaded host immune control. Here we report that naive CD8+ T cells from chronic HIV-1-infected participants on long-term cART can be primed by dendritic cells (DC. These DC must be mature, produce high levels of interleukin 12p70 (IL-12p70, be responsive to CD40 ligand (CD40L, and be loaded with inactivated, autologous HIV-1. These DC-primed CD8+ T cell responders produced high levels of gamma interferon (IFN-γ in response to a broad range of both conserved and variable regions of Gag and effectively killed CD4+ T cell targets that were either infected with the autologous latent reservoir-associated virus or loaded with autologous Gag peptides. In contrast, HIV-1-specific memory CD8+ T cells stimulated with autologous HIV-1-loaded DC produced IFN-γ in response to a narrow range of conserved and variable Gag peptides compared to the primed T cells and most notably, displayed significantly lower cytolytic function. Our findings highlight the need to selectively induce new HIV-1-specific CTL from naive precursors while avoiding activation of existing, dysfunctional memory T cells in potential curative immunotherapeutic strategies for HIV-1 infection.

  4. Antigen-specific cytotoxic T lymphocytes target airway CD103+ and CD11b+ dendritic cells to suppress allergic inflammation.

    Science.gov (United States)

    Daniels, N J; Hyde, E; Ghosh, S; Seo, K; Price, K M; Hoshino, K; Kaisho, T; Okada, T; Ronchese, F

    2016-01-01

    Allergic airway inflammation is driven by the recognition of inhaled allergen by T helper type 2 (Th2) cells in the airway and lung. Allergen-specific cytotoxic T lymphocytes (CTLs) can strongly reduce airway inflammation, however, the mechanism of their inhibitory activity is not fully defined. We used mouse models to show that allergen-specific CTLs reduced early cytokine production by Th2 cells in lung, and their subsequent accumulation and production of interleukin (IL)-4 and IL-13. In addition, treatment with specific CTLs also increased the proportion of caspase(+) dendritic cells (DCs) in mediastinal lymph node (MLN), and decreased the numbers of CD103(+) and CD11b(+) DCs in the lung. This decrease required expression of the cytotoxic mediator perforin in CTLs and of the appropriate MHC-antigen ligand on DCs, suggesting that direct CTL-DC contact was necessary. Lastly, lung imaging experiments revealed that in airway-challenged mice XCR1-GFP(+) DCs, corresponding to the CD103(+) DC subset, and XCR1-GFP(-) CD11c(+) cells, which include CD11b(+) DCs and alveolar macrophages, both clustered in the areas surrounding the small airways and were closely associated with allergen-specific CTLs. Thus, allergen-specific CTLs reduce allergic airway inflammation by depleting CD103(+) and CD11b(+) DC populations in the lung, and may constitute a mechanism through which allergic immune responses are regulated.

  5. Conjugated Polymer Solar Cells

    Science.gov (United States)

    2006-05-01

    oxygen since their EPR and conductivity data indicated the presence of unpaired charges. On the other hand, intramolecular CT complexes have recently...been reported for polythiophene [2], where weak CT occurs from a polymer unit cell to the covalently bonded acceptor molecule. Nevertheless, it was...intracavity optical doubler (532 nm), diode lasers (670, 810 nm) and light emitting diodes (490, 630 nm). Measurements were conducted for pump intensity 0.1

  6. Targeting cancer cells with folic acid-iminoboronate fluorescent conjugates.

    Science.gov (United States)

    Cal, Pedro M S D; Frade, Raquel F M; Chudasama, Vijay; Cordeiro, Carlos; Caddick, Stephen; Gois, Pedro M P

    2014-05-25

    Herein we present the synthesis of fluorescent 2-acetylbenzeneboronic acids that undergo B-N promoted conjugation with lysozyme and N-(2-aminoethyl) folic acid (EDA-FA), generating conjugates that are selectively recognized and internalized by cancer cells that over-express folic acid receptors.

  7. Conjugates of a photoactivated rhodamine with biopolymers for cell staining.

    Science.gov (United States)

    Zaitsev, Sergei Yu; Shaposhnikov, Mikhail N; Solovyeva, Daria O; Solovyeva, Valeria V; Rizvanov, Albert A

    2014-01-01

    Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids) are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD) has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan ("Chitosan-PFD") and histone H1 ("Histone H1.3-PFD"). The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK). Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes ("caged" dyes) for microscopic probing of biological objects. Thus, the synthesized "Chitosan-PFD" and "Histone H1-PFD" have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.

  8. Conjugates of a Photoactivated Rhodamine with Biopolymers for Cell Staining

    Science.gov (United States)

    Zaitsev, Sergei Yu.; Shaposhnikov, Mikhail N.; Solovyeva, Daria O.; Solovyeva, Valeria V.; Rizvanov, Albert A.

    2014-01-01

    Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids) are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD) has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan (“Chitosan-PFD”) and histone H1 (“Histone H1.3-PFD”). The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK). Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes (“caged” dyes) for microscopic probing of biological objects. Thus, the synthesized “Chitosan-PFD” and “Histone H1-PFD” have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy. PMID:25383365

  9. Conjugates of a Photoactivated Rhodamine with Biopolymers for Cell Staining

    Directory of Open Access Journals (Sweden)

    Sergei Yu. Zaitsev

    2014-01-01

    Full Text Available Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan (“Chitosan-PFD” and histone H1 (“Histone H1.3-PFD”. The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK. Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes (“caged” dyes for microscopic probing of biological objects. Thus, the synthesized “Chitosan-PFD” and “Histone H1-PFD” have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.

  10. SELECTIVE ELECTROFUSION OF CONJUGATED CELLS IN FLOW

    NARCIS (Netherlands)

    SCHUT, TCB; KRAAN, YM; BARLAG, W; DELEIJ, L; DEGROOTH, BG; GREVE, J

    1993-01-01

    Using a modified flow cytometer we have induced electrofusion of K562 and L1210 cells in flow. The two cell types are stained with two different fluorescent membrane probes, DiO and Dil, to facilitate optical recognition, and then coupled through an avidin-biotin bridge. In the flow cytometer, the h

  11. Optical Control of Living Cells Electrical Activity by Conjugated Polymers.

    Science.gov (United States)

    Martino, Nicola; Bossio, Caterina; Vaquero Morata, Susana; Lanzani, Guglielmo; Antognazza, Maria Rosa

    2016-01-28

    Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated polymers display several optimal properties as substrates for biological systems, such as good biocompatibility, excellent mechanical properties, cheap and easy processing technology, and possibility of deposition on light, thin and flexible substrates. These materials have been employed for cellular interfaces like neural probes, transistors for excitation and recording of neural activity, biosensors and actuators for drug release. Recent experiments have also demonstrated the possibility to use conjugated polymers for all-optical modulation of the electrical activity of cells. Several in-vitro study cases have been reported, including primary neuronal networks, astrocytes and secondary line cells. Moreover, signal photo-transduction mediated by organic polymers has been shown to restore light sensitivity in degenerated retinas, suggesting that these devices may be used for artificial retinal prosthesis in the future. All in all, light sensitive conjugated polymers represent a new approach for optical modulation of cellular activity. In this work, all the steps required to fabricate a bio-polymer interface for optical excitation of living cells are described. The function of the active interface is to transduce the light stimulus into a modulation of the cell membrane potential. As a study case, useful for in-vitro studies, a polythiophene thin film is used as the functional, light absorbing layer, and Human Embryonic Kidney (HEK-293) cells are employed as the biological component of the interface. Practical examples of successful control of the cell membrane potential upon stimulation with light pulses of different duration are provided. In particular, it is shown that both depolarizing and hyperpolarizing effects on the cell membrane can be achieved depending on the duration of the light stimulus. The reported

  12. Cationic Conjugated Polymers-Induced Quorum Sensing of Bacteria Cells.

    Science.gov (United States)

    Zhang, Pengbo; Lu, Huan; Chen, Hui; Zhang, Jiangyan; Liu, Libing; Lv, Fengting; Wang, Shu

    2016-03-15

    Bacteria quorum sensing (QS) has attracted significant interest for understanding cell-cell communication and regulating biological functions. In this work, we demonstrate that water-soluble cationic conjugated polymers (PFP-G2) can interact with bacteria to form aggregates through electrostatic interactions. With bacteria coated in the aggregate, PFP-G2 can induce the bacteria QS system and prolong the time duration of QS signal molecules (autoinducer-2 (AI-2)) production. The prolonged AI-2 can bind with specific protein and continuously regulate downstream gene expression. Consequently, the bacteria show a higher survival rate against antibiotics, resulting in decreased antimicrobial susceptibility. Also, AI-2 induced by PFP-G2 can stimulate 55.54 ± 12.03% more biofilm in E. coli. This method can be used to understand cell-cell communication and regulate biological functions, such as the production of signaling molecules, antibiotics, other microbial metabolites, and even virulence.

  13. SPECIFIC UPTAKE OF MONOCLONAL ANTIBODY-CONJUGATED METHOTREXATE BY HUMAN LYMPHOCYTIC LEUKEMIC B CELLS

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhenping; Yang Chunzheng; Tarunendu Ghose; Jaroslav Kralovec

    1998-01-01

    Objective: To analysis the uptake of free MTX and MTX conjugated to tumor specific monoclonal antibody by target and non-target cells. Methods: The folate antagonist methotrexate (MTX) was conjugated to two monoclonal antibodies (Mab) directed against human chronic lymphocytic leukemia (CLL), Dal B01 and Dal B02, by an active ester method. Both conjugates were more cytotoxic toward the target tumor cell line D10-1than to the non-target cell line MOLT-3, and Dal B02-MTX conjugate was more inhibitory to D10-1 cells than free MTX in a 6 h pulse exposure assay. Results: Drug uptake studies revealed that D10-1 cells took up much more Dal B01 and Dal B02-conjugated MTX than free MTX. The amounts of drug taken up by D10-1 cells incubated with Dal B01 and Dal B02-conjugated MTX were always 3 to 5-fold higher than that taken up by MOLT-3 cells, although the latter took up more drug when incubated with free MTX. Furthermore, tumor cells incubated with Dal B01 or Dal B02-conjugated MTX retained much larger amounts of drug for a prolonged period of time than those incubated with free MTX.Conclusion: The enhanced specific cytotoxicity of Dal B01 and Dal B02-MTX conjugates toward target tumor cells is therefore likely due to (Ⅰ) delivery of larger amounts of MTX to target cells when the drug is conjugated to Mab;(ii) longer retention of Mab-conjugated MTX by target cells; and (iii) slow, prolonged release of MTX from the surface-bound or endocytosed conjugates, rendering them into a sustained release dosage form.

  14. Targeted images of KB cells using folate-conjugated gold nanoparticles

    Science.gov (United States)

    Rathinaraj, Pierson; Lee, Kyubae; Park, Soo-Young; Kang, Inn-Kyu

    2015-01-01

    Mercaptosuccinic acid-coated gold (GM) nanoparticles were prepared and characterized by transmission electron microscopy and dynamic light scattering. Folic acid (F) was then conjugated to the GM to preferentially target oral squamous cancer (KB) cells with folate receptors expressed on their membranes and facilitate the transit of the nanoparticles across the cell membrane. Finally, a fluorescence dye (Atto) was conjugated to the nanoparticles to visualize their internalization into KB cells. After culture of the cells in a medium containing GM and folate-conjugated GM (GF), the interaction of surface-modified gold nanoparticles with KB cells was studied.

  15. Sequence-selective DNA binding with cell-permeable oligoguanidinium-peptide conjugates.

    Science.gov (United States)

    Mosquera, Jesús; Sánchez, Mateo I; Valero, Julián; de Mendoza, Javier; Vázquez, M Eugenio; Mascareñas, José L

    2015-03-21

    Conjugation of a short peptide fragment from a bZIP protein to an oligoguanidinium tail results in a DNA-binding miniprotein that selectively interacts with composite sequences containing the peptide-binding site next to an A/T-rich tract. In addition to stabilizing the complex with the target DNA, the oligoguanidinium unit also endows the conjugate with cell internalization properties.

  16. Humoral and cell-mediated immunity following vaccination with synthetic Candida cell wall mannan derived heptamannoside-protein conjugate: immunomodulatory properties of heptamannoside-BSA conjugate.

    Science.gov (United States)

    Paulovičová, Lucia; Paulovičová, Ema; Karelin, Alexander A; Tsvetkov, Yury E; Nifantiev, Nikolay E; Bystrický, Slavomír

    2012-10-01

    Chemically defined glycoprotein conjugate composed of synthetically prepared mannan-derived heptamannoside with terminal β-1,2-linked mannose residue attached to the α-1,3-linked mannose residues and BSA as carrier protein (M7-BSA conjugate) was analysed for the capacity to induce protective humoral immunity and appropriate alteration cellular immunity. To identify protective antigenic structure of Candida cell wall mannan M7-BSA conjugate was used for BALB/c mice immunization. The obtained results were compared with placebo group and with heat-inactivated C. albicans whole cells immunization. The administration route of M7-BSA conjugate secondary booster injection significantly affected the intensity of humoral immune response and the specificity of produced antibodies. All prepared sera were able to elevate candidacidal activity of polymorphonuclear leukocytes (PMN) in cooperation with complement. Moreover, polyclonal sera obtained after secondary subcutaneous (s.c.) booster injection of M7-BSA conjugate were able to induce candidacidal activity of PMN also in complement independent manner. M7-BSA conjugate immunization induced increases of phagocytic activity and respiratory burst of granulocytes, caused a raise of the proportion of CD3(+) T lymphocytes and increased the CD4(+)/CD8(+) T lymphocyte ratio. We observed also an increasing proportion of CD4(+)CD25(+) T cells compared to immunization with heat inactivated whole C. albicans cells, which in turn promoted an increase of the CD8(+)CD25(+) cell proportion. Immunization with M7-BSA conjugate induced Th1, Th2 and Th17 immune responses as indicated by the elevation of relevant cytokines levels. These data provide some insights on the immunomodulatory properties of oligomannosides and contribute to the development of synthetic oligosaccharide vaccines against fungal diseases.

  17. Catechins Variously Affect Activities of Conjugation Enzymes in Proliferating and Differentiated Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Kateřina Lněničková

    2016-09-01

    Full Text Available The knowledge of processes in intestinal cells is essential, as most xenobiotics come into contact with the small intestine first. Caco-2 cells are human colorectal adenocarcinoma that once differentiated, exhibit enterocyte-like characteristics. Our study compares activities and expressions of important conjugation enzymes and their modulation by green tea extract (GTE and epigallocatechin gallate (EGCG using both proliferating (P and differentiated (D caco-2 cells. The mRNA levels of the main conjugation enzymes were significantly elevated after the differentiation of Caco-2 cells. However, no increase in conjugation enzymes’ activities in differentiated cells was detected in comparison to proliferating ones. GTE/EGCG treatment did not affect the mRNA levels of any of the conjugation enzymes tested in either type of cells. Concerning conjugation enzymes activities, GTE/EGCG treatment elevated glutathione S-transferase (GST activity by approx. 30% and inhibited catechol-O-methyltransferase (COMT activity by approx. 20% in differentiated cells. On the other hand, GTE as well as EGCG treatment did not significantly affect the activities of conjugation enzymes in proliferating cells. Administration of GTE/EGCG mediated only mild changes of GST and COMT activities in enterocyte-like cells, indicating a low risk of GTE/EGCG interactions with concomitantly administered drugs. However, a considerable chemo-protective effect of GTE via the pronounced induction of detoxifying enzymes cannot be expected as well.

  18. DONOR-ACCEPTOR CONJUGATED COOLIGOMERS FOR SINGLE MOLECULE SOLAR CELLS

    Institute of Scientific and Technical Information of China (English)

    Jian-fei Qu; Jian Liu; Si-da Li; Zhi-yuan Xie; Yan-hou Geng

    2013-01-01

    Five novel donor-acceptor (D-A) conjugated cooligomers (F4B-hP,F5B-hP,F5B2[1,2]-hP,F5B2[1,3]-hP and F7B2[1,2]-hP) were synthesized.The absorption spectra of the cooligomers cover a wide range from 300 nm to 630 nm.The cooligomers could form films featured by alternating D-A lamellar nanostructures with the periods relative to the molecular lengths after thermal annealing or solvent vapor annealing.Single molecule solar cells were fabricated,and F5B-hP exhibited the best device performance.When the film of F5B-hP was thermally annealed,a power conversion efficiency (PCE) of 1.56% was realized.With solvent vapor annealing,the PCE could be further improved to 1.72% with a short-circuit current (Jsc) of 5.76 mA/cm2,an open-circuit voltage (VoC) of 0.87 V and a fill factor (FF) of 0.34.

  19. Novel curcumin diclofenac conjugate enhanced curcumin bioavailability and efficacy in streptococcal cell wall-induced arthritis

    Directory of Open Access Journals (Sweden)

    S K Jain

    2014-01-01

    Full Text Available Curcumin-diclofenac conjugate as been synthesized by esterification of phenolic group of curcumin with the acid moiety of diclofenac, and characterized by mass spectrometry, NMR, FTIR, DSC, thermogravimetric analysis and X-ray diffraction analysis. The relative solubility of curcumin-diclofenac conjugate, curcumin and diclofenac; stability of curcumin-diclofenac conjugate in intestinal extract; permeability study of curcumin-diclofenac conjugate using the everted rat intestinal sac method; stability of curcumin-diclofenac conjugate in gastrointestinal fluids and in vitro efficacy have been evaluated. In vivo bioavailability of curcumin-diclofenac conjugate and curcumin in Sprague-Dawley rats, and antiarthritic activity of curcumin-diclofenac conjugate, curcumin and diclofenac in modified streptococcal cell wall-induced arthritis model in Balb/c mice to mimic rheumatoid arthritis in humans have also been studied. In all of the above studies, curcumin-diclofenac conjugate exhibited enhanced stability as compared to curcumin; its activity was twice that of diclofenac in inhibiting thermal protein denaturation taken as a measure of in vitro antiinflammatory activity; it enhanced the bioavailability of curcumin by more than five folds, and significantly (P<0.01 alleviated the symptoms of arthritis in streptococcal cell wall-induced arthritis model as compared to both diclofenac and curcumin.

  20. Antibody-protein A conjugated quantum dots for multiplexed imaging of surface receptors in living cells.

    Science.gov (United States)

    Jin, Takashi; Tiwari, Dhermendra K; Tanaka, Shin-Ichi; Inouye, Yasushi; Yoshizawa, Keiko; Watanabe, Tomonobu M

    2010-11-01

    To use quantum dots (QDs) as fluorescent probes for receptor imaging, QD surface should be modified with biomolecules such as antibodies, peptides, carbohydrates, and small-molecule ligands for receptors. Among these QDs, antibody conjugated QDs are the most promising fluorescent probes. There are many kinds of coupling reactions that can be used for preparing antibody conjugated QDs. Most of the antibody coupling reactions, however, are non-selective and time-consuming. In this paper, we report a facile method for preparing antibody conjugated QDs for surface receptor imaging. We used ProteinA as an adaptor protein for binding of antibody to QDs. By using ProteinA conjugated QDs, various types of antibodies are easily attached to the surface of the QDs via non-covalent binding between the F(c) (fragment crystallization) region of antibody and ProteinA. To show the utility of ProteinA conjugated QDs, HER2 (anti-human epidermal growth factor receptor 2) in KPL-4 human breast cancer cells were stained by using anti-HER2 antibody conjugated ProteinA-QDs. In addition, multiplexed imaging of HER2 and CXCR4 (chemokine receptor) in the KPL-4 cells was performed. The result showed that CXCR4 receptors coexist with HER2 receptors in the membrane surface of KPL-4 cells. ProteinA mediated antibody conjugation to QDs is very useful to prepare fluorescent probes for multiplexed imaging of surface receptors in living cells.

  1. Linker-free conjugation and specific cell targeting of antibody functionalized iron-oxide nanoparticles

    Science.gov (United States)

    Xu, Yaolin; Baiu, Dana C.; Sherwood, Jennifer A.; McElreath, Meghan R.; Qin, Ying; Lackey, Kimberly H.; Otto, Mario; Bao, Yuping

    2015-01-01

    Specific targeting is a key step to realize the full potential of iron oxide nanoparticles in biomedical applications, especially tumor-associated diagnosis and therapy. Here, we developed anti-GD2 antibody conjugated iron oxide nanoparticles for highly efficient neuroblastoma cell targeting. The antibody conjugation was achieved through an easy, linker-free method based on catechol reactions. The targeting efficiency and specificity of the antibody-conjugated nanoparticles to GD2-positive neuroblastoma cells were confirmed by flow cytometry, fluorescence microscopy, Prussian blue staining and transmission electron microscopy. These detailed studies indicated that the receptor-recognition capability of the antibody was fully retained after conjugation and the conjugated nanoparticles quickly attached to GD2-positive cells within four hours. Interestingly, longer treatment (12 h) led the cell membrane-bound nanoparticles to be internalized into cytosol, either by directly penetrating the cell membrane or escaping from the endosomes. Last but importantly, the uniquely designed functional surfaces of the nanoparticles allow easy conjugation of other bioactive molecules. PMID:26660881

  2. The modulation of biodistribution of stem cells by anchoring lipid-conjugated heparin on the cell surface.

    Science.gov (United States)

    Kim, Jong Chul; Tae, Giyoong

    2015-11-10

    Heparin is a bioactive glycosaminoglycan that can interact with various extracellular matrix (ECM) proteins and growth factors. Lipid-conjugated heparin was synthesized, and was used to coat adipose-derived stem cells (ADSCs) by physical insertion on the cell membrane. Coating of lipid-conjugated heparin with two lipid moieties on ADSCs was stable for 24h in vitro. Biodistribution of heparin-coated ADSCs upon intravenous injection in mice was analyzed by In-Vivo Imaging System (IVIS), and showed enhanced accumulation in the liver and spleen while reduced entrapment in the lung. Thus, the coating of ADSCs with lipid-conjugated heparin could significantly modulate the biodistribution of cells.

  3. Uptake of Single-Walled Carbon Nanotubes Conjugated with DNA by Microvascular Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Joseph Harvey

    2012-01-01

    Full Text Available Single-walled carbon nanotubes (SWCNTs have been proposed to have great therapeutic potential. SWCNTs conjugated with drugs or genes travel in the systemic circulation to reach target cells or tissues following extravasation from microvessels although the interaction between SWCNT conjugates and the microvascular endothelial cells (ECs remains unknown. We hypothesized that SWCNT-DNA conjugates would be taken up by microvascular ECs and that this process would be facilitated by SWCNTs compared to facilitation by DNA alone. ECs were treated with various concentrations of SWCNT-DNA-FITC conjugates, and the uptake and intracellular distribution of these conjugates were determined by a confocal microscope imaging system followed by quantitative analysis of fluorescence intensity. The uptake of SWCNT-DNA-FITC conjugates (2 μg/mL by microvascular ECs was significantly greater than that of DNA-FITC (2 μg/mL, observed at 6 hrs after treatment. For the intracellular distribution, SWCNT-DNA-FITC conjugates were detected in the nucleus of ECs, while DNA-FITC was restricted to the cytoplasm. The fluorescence intensity and distribution of SWCNTs were concentration and time independent. The findings demonstrate that SWCNTs facilitate DNA delivery into microvascular ECs, thus suggesting that SWCNTs serving as drug and gene vehicles have therapeutic potential.

  4. Conjugation of the mycotoxins alternariol and alternariol monomethyl ether in tobacco suspension cells.

    Science.gov (United States)

    Hildebrand, Andreas A; Kohn, Beate N; Pfeiffer, Erika; Wefers, Daniel; Metzler, Manfred; Bunzel, Mirko

    2015-05-20

    The mycotoxins alternariol (AOH) and alternariol-9-O-methyl ether (AME) carry three and two phenolic hydroxyl groups, respectively, which makes them candidates for the formation of conjugated metabolites in plants. Such conjugates may escape routine methods of analysis and have therefore been termed masked or, more recently, modified mycotoxins. We report now that AOH and AME are extensively conjugated in suspension cultures of tobacco BY-2 cells. Five conjugates of AOH were identified by MS and NMR spectroscopy as β-D-glucopyranosides (attached in AOH 3- or 9-position) as well as their 6'-malonyl derivatives, and as a gentiobiose conjugate. For AME, conjugation resulted in the d-glucopyranoside (mostly attached in the AME 3-position) and its 6'- and 4'-malonyl derivatives. Pronounced differences were noted for the quantitative pattern of AOH and AME conjugates as well as for their phytotoxicity. Our in vitro study demonstrates for the first time that masked mycotoxins of AOH and AME can be formed in plant cells.

  5. Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Toshikazu; Kawai-Noma, Shigeko [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Pack, Chan-Gi [Cellular Informatics Laboratory, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Terajima, Hideki [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Yajima, Junichiro; Nishizaka, Takayuki [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan); Kinjo, Masataka [Laboratory of Molecular Cell Dynamics, Graduate School of Life Sciences, Hokkaido University, Sapporo 001-0021 (Japan); Taguchi, Hideki, E-mail: taguchi@bio.titech.ac.jp [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan)

    2011-02-25

    Research highlights: {yields} We develop a method to track a quantum dot-conjugated protein in yeast cells. {yields} We incorporate the conjugated quantum dot proteins into yeast spheroplasts. {yields} We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

  6. Cytotoxicity Effects of Different Surfactant Molecules Conjugated to Carbon Nanotubes on Human Astrocytoma Cells

    Science.gov (United States)

    Dong, Lifeng; Witkowski, Colette M.; Craig, Michael M.; Greenwade, Molly M.; Joseph, Katherine L.

    2009-12-01

    Phase contrast and epifluorescence microscopy were utilized to monitor morphological changes in human astrocytoma cells during a time-course exposure to single-walled carbon nanotube (SWCNT) conjugates with different surfactants and to investigate sub-cellular distribution of the nanotube conjugates, respectively. Experimental results demonstrate that cytotoxicity of the nanotube/surfactant conjugates is related to the toxicity of surfactant molecules attached on the nanotube surfaces. Both sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) are toxic to cells. Exposure to CNT/SDS conjugates (0.5 mg/mL) for less than 5 min caused changes in cell morphology resulting in a distinctly spherical shape compared to untreated cells. In contrast, sodium cholate (SC) and CNT/SC did not affect cell morphology, proliferation, or growth. These data indicate that SC is an environmentally friendly surfactant for the purification and dispersion of SWCNTs. Epifluorescence microscopy analysis of CNT/DNA conjugates revealed distribution in the cytoplasm of cells and did not show adverse effects on cell morphology, proliferation, or viability during a 72-h incubation. These observations suggest that the SWCNTs could be used as non-viral vectors for diagnostic and therapeutic molecules across the blood-brain barrier to the brain and the central nervous system.

  7. Cytotoxicity Effects of Different Surfactant Molecules Conjugated to Carbon Nanotubes on Human Astrocytoma Cells

    Directory of Open Access Journals (Sweden)

    Witkowski Colette

    2009-01-01

    Full Text Available Abstract Phase contrast and epifluorescence microscopy were utilized to monitor morphological changes in human astrocytoma cells during a time-course exposure to single-walled carbon nanotube (SWCNT conjugates with different surfactants and to investigate sub-cellular distribution of the nanotube conjugates, respectively. Experimental results demonstrate that cytotoxicity of the nanotube/surfactant conjugates is related to the toxicity of surfactant molecules attached on the nanotube surfaces. Both sodium dodecyl sulfate (SDS and sodium dodecylbenzene sulfonate (SDBS are toxic to cells. Exposure to CNT/SDS conjugates (0.5 mg/mL for less than 5 min caused changes in cell morphology resulting in a distinctly spherical shape compared to untreated cells. In contrast, sodium cholate (SC and CNT/SC did not affect cell morphology, proliferation, or growth. These data indicate that SC is an environmentally friendly surfactant for the purification and dispersion of SWCNTs. Epifluorescence microscopy analysis of CNT/DNA conjugates revealed distribution in the cytoplasm of cells and did not show adverse effects on cell morphology, proliferation, or viability during a 72-h incubation. These observations suggest that the SWCNTs could be used as non-viral vectors for diagnostic and therapeutic molecules across the blood–brain barrier to the brain and the central nervous system.

  8. DNA-templated antibody conjugation for targeted drug delivery to cancer cells

    DEFF Research Database (Denmark)

    Liu, Tianqiang

    2016-01-01

    -templated organic synthesis due to the wide existence of the 3-histidine cluster in most wild-type proteins. In this thesis, three projects that relate to targeted drug delivery to cancer cells based on the DTPC method is described. The first project was a delivery system which uses transferrin as the targeting...... ligand and saporin (ribosome inactivating protein) as the warhead to achieve enhanced cellular uptake and cytotoxicity of saporin to transferrin receptor overexpressed cancer cell line. The transferrin-saporin conjugate complex are formed by linking the site-selective DNA-transferrin conjugates with mono...... to cancer cells. The DNA duplex in the conjugates could be used for doxorubicin intercalation since it contains CGA repeats. Confocal microscopy and flow cytometry results showed a receptor-mediated targeting manner to EGFR+ cancer cell lines (KB and MDA-MB-231), and resulted in enhanced cell killing...

  9. Integrin Targeting and Toxicological Assessment of Peptide-Conjugated Liposome Delivery Systems to Activated Endothelial Cells

    DEFF Research Database (Denmark)

    Kermanizadeh, Ali; Villadsen, Klaus; Østrem, Ragnhild Garborg

    2017-01-01

    Utilisation of functionalized liposomes as the means of targeted delivery of therapeutics may enhance specific transport of biologically active drugs to target tissues, while avoiding or reducing undesired side effects. In the present investigation, peptide-conjugated cationic liposomes were cons....... Therefore, this study demonstrates the feasibility of constructing a peptide-conjugated cationic liposome, which displays targeting to activated endothelial cells at concentrations that are not cytotoxic or inflammogenic to the cells....... constructed with the aim of targeting integrins (i.e. vitronectin and/or fibronectin receptors) on activated endothelial cells. The peptide-conjugated liposomes induced only cytotoxicity at the highest concentration in non-activated or activated endothelial cells, as well as in co-culture of endothelial cells...

  10. R-phycoerythrin-conjugated antibodies are inappropriate for intracellular staining of murine plasma cells.

    Science.gov (United States)

    Kim, Myun Soo; Kim, Tae Sung

    2013-05-01

    Phycoerythrin (PE) is a type of phycobiliproteins found in cyanobacteria and red algae. PE-conjugated antibodies are broadly used for flow cytometry and immunofluorescence microscopy. Because nonspecific binding of antibodies results in decreased analytic accuracy, numerous efforts have been made to unveil cases and mechanisms of nonspecific bindings. However, nonspecific binding of specific cell types by a fluorescent dye-conjugated form of antibody has been rarely reported. In the present study, we discovered that PE-conjugated antibodies, but not FITC- or APC-antibodies, selectively stained lamina propria plasma cells (LP-PCs) from the murine small intestine after membrane permeabilization. We demonstrated that LP-PC-selective staining with PE-antibodies was not due to interactions of antibody-epitope or antibody-Fc receptor. This unexpected staining by PE-antibody was not dependent on the mouse strain of LP-PCs, experimental methods, or origin species of the antibody, but dependent on PE itself. This phenomenon was also observed in plasma cells isolated from bone marrow, spleen, and mesenteric lymph nodes. Furthermore, in vitro activated B cells and in vivo generated LP-PCs were also selectively stained by PE-conjugated antibodies. Taken together, these results show that PE-conjugated antibodies are inappropriate for intracellular staining of murine plasma cells.

  11. Herceptin conjugates linked by EDC boost direct tumor cell death via programmed tumor cell necrosis.

    Directory of Open Access Journals (Sweden)

    Jiemiao Hu

    Full Text Available Tumor-targeted antibody therapy is one of the safest biological therapeutics for cancer patients, but it is often ineffective at inducing direct tumor cell death and is ineffective against resistant tumor cells. Currently, the antitumor efficacy of antibody therapy is primarily achieved by inducing indirect tumor cell death, such as antibody-dependent cell cytotoxicity. Our study reveals that Herceptin conjugates, if generated via the crosslinker EDC (1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride, are capable of engendering human epidermal growth factor receptor 2 (Her2 positive tumor cells death. Using a high-performance liquid chromatography (HPLC system, three peaks with estimated molecular weights of antibody monomer, dimer, and trimer were isolated. Both Herceptin trimer and dimer separated by HPLC induced significant levels of necrotic tumor cell death, although the trimer was more effective than the dimer. Notably, the Herceptin trimer also induced Herceptin-resistant tumor cell death. Surprisingly different from the known cell death mechanism that often results from antibody treatment, the Herceptin trimer elicited effective and direct tumor cell death via a novel mechanism: programmed cell necrosis. In Her2-positive cells, inhibition of necrosis pathways significantly reversed Herceptin trimer-induced cell death. In summary, the Herceptin trimer reported herein harbors great potential for overcoming tumor cell resistance to Herceptin treatment.

  12. Characterization of large area flexible plastic solar cells based on conjugated polymer/fullerene composites

    NARCIS (Netherlands)

    Gebeyehu, Desta; Padinger, F.; Brabec, C.J.; Fromherz, T.; Hummelen, J.C.; Sariciftci, N.S.

    1999-01-01

    The development of solar cells based on composites of organic conjugated semi-conducting polymers with fullerene derivatives can provide a new method in the exploitation of solar energy. Organic solar cells must fulfill the criteria of stability, efficiency and reduction of production costs to find

  13. Stability issues of conjugated polymer/fullerene solar cells from a chemical viewpoint

    NARCIS (Netherlands)

    Hummelen, JC; Knol, J; Sanchez, L; Kafafi, ZH

    2000-01-01

    The efficiency of energy conversion and the stability or lifetime of 'plastic' photovoltaic cells, based on conjugated polymer/ fullerene blends, are the two main issues to be improved for this type of devices. The stability of these PV cells depends potentially on a large number of factors. A brief

  14. Role of multidrug resistance protein (MRP) in glutathione S-conjugate transport in mammalian cells

    NARCIS (Netherlands)

    Muller, M; deVries, EGE; Jansen, PLM

    1996-01-01

    The human multidrug resistance protein (MRP), a 190-kDa member of the ABC-protein superfamily, is an ATP-dependent glutathione S-conjugate carrier (GS-X pump) and is present in membranes of many, if not all, cells, Overexpression of MRP in tumor cells contributes to resistance to natural product dru

  15. Biotin-conjugated fusogenic liposomes for high-quality cell purification.

    Science.gov (United States)

    Hersch, Nils; Wolters, Benjamin; Ungvari, Zoltan; Gautam, Tripti; Deshpande, Dhruva; Merkel, Rudolf; Csiszar, Anna; Hoffmann, Bernd; Csiszár, Agnes

    2016-01-01

    Purification of defined cell populations from mixed primary cell sources is essential for many biomedical and biotechnological applications but often very difficult to accomplish due to missing specific surface markers. In this study, we developed a new approach for efficient cell population separation based on the specific membrane fusion characteristics of distinct cell types upon treatment with fusogenic liposomes. When such liposomes are conjugated with biotin, specific cell populations can be efficiently surface functionalized by biotin after liposomal treatment while other populations remain unlabeled. Due to the high affinity of biotin for avidin-like proteins, biotin functionalized cells are ideal targets for conjugation of e.g. avidin tagged magnetic beads, fluorophores or antibodies with bioanalytical relevance. Here, based on the differential biotinylation of distinct cell populations high quality separation of cardiac fibroblasts from myocytes, and cerebromicrovascular endothelial cells from fibroblasts was successfully established.

  16. Evaluation of chemical fluorescent dyes as a protein conjugation partner for live cell imaging.

    Directory of Open Access Journals (Sweden)

    Yoko Hayashi-Takanaka

    Full Text Available To optimize live cell fluorescence imaging, the choice of fluorescent substrate is a critical factor. Although genetically encoded fluorescent proteins have been used widely, chemical fluorescent dyes are still useful when conjugated to proteins or ligands. However, little information is available for the suitability of different fluorescent dyes for live imaging. We here systematically analyzed the property of a number of commercial fluorescent dyes when conjugated with antigen-binding (Fab fragments directed against specific histone modifications, in particular, phosphorylated H3S28 (H3S28ph and acetylated H3K9 (H3K9ac. These Fab fragments were conjugated with a fluorescent dye and loaded into living HeLa cells. H3S28ph-specific Fab fragments were expected to be enriched in condensed chromosomes, as H3S28 is phosphorylated during mitosis. However, the degree of Fab fragment enrichment on mitotic chromosomes varied depending on the conjugated dye. In general, green fluorescent dyes showed higher enrichment, compared to red and far-red fluorescent dyes, even when dye:protein conjugation ratios were similar. These differences are partly explained by an altered affinity of Fab fragment after dye-conjugation; some dyes have less effect on the affinity, while others can affect it more. Moreover, red and far-red fluorescent dyes tended to form aggregates in the cytoplasm. Similar results were observed when H3K9ac-specific Fab fragments were used, suggesting that the properties of each dye affect different Fab fragments similarly. According to our analysis, conjugation with green fluorescent dyes, like Alexa Fluor 488 and Dylight 488, has the least effect on Fab affinity and is the best for live cell imaging, although these dyes are less photostable than red fluorescent dyes. When multicolor imaging is required, we recommend the following dye combinations for optimal results: Alexa Fluor 488 (green, Cy3 (red, and Cy5 or CF640 (far-red.

  17. Mycobacterial cell-wall skeleton as a universal vaccine vehicle for antigen conjugation.

    Science.gov (United States)

    Paik, Tae-Hyun; Lee, Ji-Sook; Kim, Ki-Hye; Yang, Chul-Su; Jo, Eun-Kyeong; Song, Chang-Hwa

    2010-11-23

    Mycobacterial cell-wall skeleton (CWS) is an immunoactive and biodegradable particulate adjuvant and has been used for immunotherapy in patients with cancer. The CWS of Mycobacterium bovis bacillus Calmette-Guérin (BCG-CWS) was studied as a universal vaccine vehicle for antigen conjugation, to develop potentially effective and safe vaccines. Here, we describe experiments in which protein antigens, such as keyhole limpet haemocyanin (KLH), ovalbumin (OVA) and bovine serum albumin (BSA) were highly efficiently coupled to 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC/NHS)-activated carboxyl groups of BCG-CWS, and tested the immunogenicity of OVA-conjugated BCG-CWS vaccine. We found that a strong immune response was induced in mice immunised with OVA-conjugated BCG-CWS, which was similar to the enhancement of the immune responses in mice immunised with OVA and complete Freund's adjuvant. Covalent conjugation of OVA to BCG-CWS was essential for Th1-skewed immune responses, with prominent expression of IFN-γ. Furthermore, antigen-conjugated BCG-CWS vaccine is simple to manufacture, safe, and easy to use. Our results suggest that mycobacterial CWS as a universal vaccine vehicle for conjugation of a wide variety of antigens constitutes a breakthrough for development of the most promising vaccines for infections, allergic diseases, and cancer.

  18. Folate-conjugated immunoglobulin targets melanoma tumor cells for NK cell effector functions

    Science.gov (United States)

    Skinner, Cassandra C.; McMichael, Elizabeth L.; Jaime-Ramirez, Alena C.; Abrams, Zachary B.; Lee, Robert J.; Carson, William E.

    2016-01-01

    The folate receptor (FR) is over-expressed on the vascular side of cancerous cells including those of the breast, ovaries, testes, and cervix. We hypothesized that a folate-conjugated immunoglobulin (F-IgG) would bind to the FR that is over-expressed on melanoma tumor cells to target these cells for lysis by natural killer (NK) cells. Folate receptor expression was confirmed in the Mel-39 (human melanoma) cell line by flow cytometry and immunoblot analysis, using KB (human oral epithelial) and F01 (human melanoma) as a positive and negative control, respectively. FR-positive and negative cell lines were treated with F-IgG or control immunoglobulin G (C-IgG) in the presence or absence of cytokines in order to determine NK cell ability to lyse FR-positive cell lines. NK cell activation was significantly upregulated and lysis of Mel 39 tumor cells enhanced following treatment with F-IgG, as compared to C-IgG at all effector:target (E:T) ratios (p<0.01). This trend was further enhanced by NK cell stimulation with the activating cytokine interleukin-12 (IL-12). NK cell production of cytokines such as interferon-gamma (IFN-γ), macrophage inflammatory protein 1 alpha (MIP-1α), and regulated on activation normal T-cell expressed and secreted (RANTES) were also significantly increased in response to co-stimulation with IL-12 stimulation and F-IgG-coated Mel 39 target cells, as compared to controls (p<0.01). In contrast, F-IgG did not bind to the FR-negative cell line F01 and had no significant effect on NK cell lysis or cytokine production. This research indicates the potential use of F-IgG for its ability to induce an immune response from NK cells against FR-positive melanoma tumor cells which can be further enhanced by the addition of cytokines. PMID:27035691

  19. Drug resistance to chlorambucil in murine B-cell leukemic cells is overcome by its conjugation to a targeting peptide.

    Science.gov (United States)

    Gellerman, Gary; Baskin, Sophia; Galia, Luboshits; Gilad, Yosef; Firer, Michael A

    2013-02-01

    Targeting drugs through small-molecule carriers with a high affinity to receptors on cancer cells can overcome the lack of target cell specificity of most anticancer drugs. These targeted carrier-drug conjugates are also capable of reversing drug resistance in cancer cells. Although many targeted drug delivery approaches are being tested, the linkage of several and different drugs to a single carrier molecule might further enhance their therapeutic efficacy, particularly if the drugs are engineered for variable time release. This report shows that murine B-cell leukemic cells previously resistant to a chemotherapeutic drug can be made sensitive to that drug as long as it is conjugated to a targeting peptide and, in particular, when the conjugate contains multiple copies of the drug. Using a 13mer peptide (VHFFKNIVTPRTP) derived from the myelin basic protein (p-MBP), dendrimer-based peptide conjugates containing one, two, or four molecules of chlorambucil were synthesized. Although murine hybridomas expressing antibodies to either p-MBP (MBP cells) or a nonrelevant antigen (BCL-1 cells) were both resistant to free chlorambucil, exposure of the cells to the p-MBP-chlorambucil conjugate completely reversed the drug resistance in MBP, but not BCL-1 cells or normal spleen cells. Moreover, at equivalent drug doses, there was significant enhancement in the cytotoxic activity of multidrug versus single-drug copy conjugates. On the basis of these results, the use of multifunctional dendrone linkers bearing several covalently bound cytotoxic agents allows the development of more effective targeted drug systems and enhances the efficacy of currently approved drugs for B-cell leukemia.

  20. Cellular uptake of antisense oligonucleotides after complexing or conjugation with cell-penetrating model peptides.

    Science.gov (United States)

    Oehlke, J; Birth, P; Klauschenz, E; Wiesner, B; Beyermann, M; Oksche, A; Bienert, M

    2002-08-01

    The uptake by mammalian cells of phosphorothioate oligonucleotides was compared with that of their respective complexes or conjugates with cationic, cell-penetrating model peptides of varying helix-forming propensity and amphipathicity. An HPLC-based protocol for the synthesis and purification of disulfide bridged conjugates in the 10-100 nmol range was developed. Confocal laser scanning microscopy (CLSM) in combination with gel-capillary electrophoresis and laser induced fluorescence detection (GCE-LIF) revealed cytoplasmic and nuclear accumulationin all cases. The uptake differences between naked oligonucleotides and their respective peptide complexes or conjugates were generally confined to one order of magnitude. No significant influence of the structural properties of the peptide components upon cellular uptake was found. Our results question the common belief that the increased biological activity of oligonucleotides after derivatization with membrane permeable peptides may be primarily due to improved membrane translocation.

  1. Use of quantum dot-conjugated antibodies to study intracellular cancer biomarkers in living and fixed cells

    Science.gov (United States)

    Ling, Jian

    2008-02-01

    Quantum dots have unique properties for long-term immunofluorescence imaging of molecular activities inside living cells. The key is how to deliver the quantum dot-conjugated antibodies into cells and further allow the antibodies freely move inside cells to bind target molecules. This study investigated the feasibility of using Pep-1, a cell penetration protein, to facilitate the internalization of quantum dot-conjugated antibodies for the labeling of two intracellular cervical cancer biomarkers: p16 and Mcm5. Quantum dots were directly conjugated with the antibodies to p16 and Mcm5 and, they were able to stain fixed cells and to differentiate biomarker positive and negative cells. The non-covalent binding between the conjugates and Pep-1 peptides allows the quick internalization of the quantum dot-conjugated antibodies into living cells. The internalized conjugates were concentrated in the perinuclear regions of the biomarker-positive HeLa cells. In the biomarker negative Um-Uc-3 cells, however, the conjugates concentrated in juxtaneclear region. Cells bearing with quantum dots still go through the mitosis process. Although the study indicates many questions need to be answered and many problems need to be solved, the use of cell penetration peptide is a promising method for the intracellular labeling of living cell molecules using quantum dots.

  2. Human glutathione S-transferase-mediated glutathione conjugation of curcumin and efflux of these conjugates in caco-2 cells

    NARCIS (Netherlands)

    Usta, M.; Wortelboer, H.M.; Vervoort, J.; Boersma, M.G.; Rietjens, I.M.C.M.; Bladeren, P.J. van; Cnubben, N.H.P.

    2007-01-01

    Curcumin, an α,β-unsaturated carbonyl compound, reacts with glutathione, leading to the formation of two monoglutathionyl curcumin conjugates. In the present study, the structures of both glutathione conjugates of curcumin were identified by LC-MS and one- and two-dimensional 1H NMR analysis, and th

  3. Multiplexed detection of various breast cancer cells by perfluorocarbon/quantum dot nanoemulsions conjugated with antibodies

    Science.gov (United States)

    Bae, Pan Kee; Chung, Bong Hyun

    2014-07-01

    The effective targeting of cancer cell surface antigens is an attractive approach in cancer diagnosis and therapy. Multifunctional nanoprobes with cell-targeting specificity are likely to find important applications in bioanalysis, biomedicine, and clinical diagnosis. In this study, we have fabricated biocompatible perfluorocan/quantum dot nanoemulsions as bimodal imaging nanoprobes for the targeting of breast cancer cells. Perfluorocarbon/quantum dot nanoemulsions conjugated with monoclonal antibodies, as a type of bimodal imaging nanoprobe based on 19 F-MR and optical imaging, have been synthesized and applied for targeted imaging of three different breast cancer cells (SKBR3, MCF-7, MDA-MB 468), respectively. We have shown that the cancer-detection capabilities of antibody-conjugated PFC/QDs nanoemulsions could be successfully applied to target of various breast cancer cells. These modified PFC/QDs nanoemulsions were shown to target the cancer cell surface receptors specially. Conjugation of ligands to nanoemulsions targeting over-expressed cell surface receptors is a promising approach for targeted imaging to tumor cells. We further propose that the PFC/QDs nanoemulsions could be used in targeted imaging of breast cancer cells.

  4. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes.

    Science.gov (United States)

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-03-02

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application.

  5. Non-preconditioned conjugate gradient on cell and FPCA-based hybrid supercomputer nodes

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, David H [Los Alamos National Laboratory; Dubois, Andrew J [Los Alamos National Laboratory; Boorman, Thomas M [Los Alamos National Laboratory; Connor, Carolyn M [Los Alamos National Laboratory

    2009-03-10

    This work presents a detailed implementation of a double precision, Non-Preconditioned, Conjugate Gradient algorithm on a Roadrunner heterogeneous supercomputer node. These nodes utilize the Cell Broadband Engine Architecture{trademark} in conjunction with x86 Opteron{trademark} processors from AMD. We implement a common Conjugate Gradient algorithm, on a variety of systems, to compare and contrast performance. Implementation results are presented for the Roadrunner hybrid supercomputer, SRC Computers, Inc. MAPStation SRC-6 FPGA enhanced hybrid supercomputer, and AMD Opteron only. In all hybrid implementations wall clock time is measured, including all transfer overhead and compute timings.

  6. Non-preconditioned conjugate gradient on cell and FPGA based hybrid supercomputer nodes

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, David H [Los Alamos National Laboratory; Dubois, Andrew J [Los Alamos National Laboratory; Boorman, Thomas M [Los Alamos National Laboratory; Connor, Carolyn M [Los Alamos National Laboratory

    2009-01-01

    This work presents a detailed implementation of a double precision, non-preconditioned, Conjugate Gradient algorithm on a Roadrunner heterogeneous supercomputer node. These nodes utilize the Cell Broadband Engine Architecture{sup TM} in conjunction with x86 Opteron{sup TM} processors from AMD. We implement a common Conjugate Gradient algorithm, on a variety of systems, to compare and contrast performance. Implementation results are presented for the Roadrunner hybrid supercomputer, SRC Computers, Inc. MAPStation SRC-6 FPGA enhanced hybrid supercomputer, and AMD Opteron only. In all hybrid implementations wall clock time is measured, including all transfer overhead and compute timings.

  7. Inhibitory effect of gold nanoparticles conjugated with interferon gamma and methionine on breast cancer cell line

    Institute of Scientific and Technical Information of China (English)

    Nastaran Mohseni; Fatemeh Salehi Sarvestani; Mehdi Shafiee Ardestani; Fatemeh Kazemi-Lomedasht; Masoud Ghorbani

    2016-01-01

    Objective: To develop a gold nanoparticles complex conjugated with interferon-gamma(IFN-g) and methionine along with application of hyperthermia using near-infrared laser beams for the treatment of cancer cells.Methods: Gold nanorods(10 nm) were conjugated with IFN-g and methionine using carbodiimide family and characterized after purification by dialysis bags. Breast cancer cells were cultured and incubated with gold nanorods at different concentrations followed by irradiation with near-infrared laser beam. Samples were then evaluated for their viability in order to determine the effect of treatment and variables by MTT assy.Results: Zetasizer results confirmed the conjugation of gold nanorods with methionine and IFN-g. The median percentage of cell viability in 0.30 mg/m L concentration of gold nanorods was 82%. The cell viability reached to 85% at the same concentration of gold nanorods, which existed in the assayed complex. The results of MTT assay showed that the 0.60 mg/m L concentration of gold nanoparticles complex was toxic on tumor cells(P < 0.05). After exposure to hyperthermia, the viability of cells at 6 min decreased to77% in 0.30 mg/m L concentration of gold nanorods complex.Conclusions: The size and concentration of gold nanorods was not cytotoxic. However,their presence during irradiation near-infrared laser increased the number of dead cells during the treatment of cells.

  8. Nanostructured Conjugated Polymers for Energy-Related Applications beyond Solar Cells.

    Science.gov (United States)

    Xie, Jian; Zhao, Cui-E; Lin, Zong-Qiong; Gu, Pei-Yang; Zhang, Qichun

    2016-05-20

    To meet the ever-increasing requirements for the next generation of sustainable and versatile energy-related devices, conjugated polymers, which have potential advantages over small molecules and inorganic materials, are among the most promising types of green candidates. The properties of conjugated polymers can be tuned through modification of the structure and incorporation of different functional moieties. In addition, superior performances can be achieved as a result of the advantages of nanostructures, such as their large surface areas and the shortened pathways for charge transfer. Therefore, nanostructured conjugated polymers with different properties can be obtained to be applied in different energy-related organic devices. This review focuses on the application and performance of the recently reported nanostructured conjugated polymers for high-performance devices, including rechargeable lithium batteries, microbial fuel cells (MFCs), thermoelectric generators, and photocatalytic systems. The design strategies, reaction mechanisms, advantages, and limitations of nanostructured conjugated polymers are further discussed in each section. Finally, possible routes to improve the performances of the current systems are also included in the conclusion.

  9. A novel 2,6-diisopropylphenyl-docosahexaenoamide conjugate induces apoptosis in T cell acute lymphoblastic leukemia cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Altenburg, Jeffrey D.; Harvey, Kevin A.; McCray, Sharon; Xu, Zhidong [Cellular Biochemistry Laboratory, Methodist Research Institute, Indiana University Health, Indianapolis, IN (United States); Siddiqui, Rafat A., E-mail: rsiddiqu@iuhealth.org [Cellular Biochemistry Laboratory, Methodist Research Institute, Indiana University Health, Indianapolis, IN (United States); Department of Biology, Indiana University-Purdue University, Indianapolis, IN (United States); Department of Medicine, Indiana University School of Medicine, Indianapolis, IN (United States)

    2011-07-29

    Highlights: {yields} 2,6-Diisopropylphenyl-docosahexaenoamide conjugates (DIP-DHA) inhibits the proliferation of T-cell leukemic cell lines. {yields} DIP-DHA resulted in increased activation of caspase-3, and caspase-7. {yields} DIP-DHA significantly downregulated CXCR4 surface expression. -- Abstract: We have previously characterized the effects of 2,6-diisopropylphenyl-docosahexaenoamide (DIP-DHA) conjugates and their analogs on the proliferation and progression of breast cancer cell lines. For this study, we investigated the effects of the DIP-DHA conjugate on 2 representative T cell acute lymphoblastic leukemia (T-ALL) cell lines: CEM and Jurkat. Treatment of both cell lines with DIP-DHA resulted in significantly greater inhibition of proliferation and induction of apoptosis than that of parent compounds, 2,6-diisopropylphenol (DIP) or docosahexaenoate (DHA). Treatment of the cells with DIP-DHA resulted in increased activation of caspase-3, and caspase-7. Furthermore, induction of apoptosis in both cell lines was reversed in the presence of a caspase family inhibitor. Treatment with DIP-DHA reduced mitochondrial membrane potential. These observations suggest that the effects are driven by intrinsic apoptotic pathways. DIP-DHA treatment also downregulated surface CXCR4 expression, an important chemokine receptor involved in cancer metastasis that is highly expressed in both CEM and Jurkat cells. In conclusion, our data suggest that the DIP-DHA conjugate exhibits significantly more potent effects on CEM and Jurkat cells than that of DIP or DHA alone. These conjugates have potential use for treatment of patients with T cell acute lymphoblastic leukemia.

  10. Cell Penetrating Peptide Conjugated Chitosan for Enhanced Delivery of Nucleic Acid

    Directory of Open Access Journals (Sweden)

    Buddhadev Layek

    2015-12-01

    Full Text Available Gene therapy is an emerging therapeutic strategy for the cure or treatment of a spectrum of genetic disorders. Nevertheless, advances in gene therapy are immensely reliant upon design of an efficient gene carrier that can deliver genetic cargoes into the desired cell populations. Among various nonviral gene delivery systems, chitosan-based carriers have gained increasing attention because of their high cationic charge density, excellent biocompatibility, nearly nonexistent cytotoxicity, negligible immune response, and ideal ability to undergo chemical conjugation. However, a major shortcoming of chitosan-based carriers is their poor cellular uptake, leading to inadequate transfection efficiency. The intrinsic feature of cell penetrating peptides (CPPs for transporting diverse cargoes into multiple cell and tissue types in a safe manner suggests that they can be conjugated to chitosan for improving its transfection efficiency. In this review, we briefly discuss CPPs and their classification, and also the major mechanisms contributing to the cellular uptake of CPPs and cargo conjugates. We also discuss immense improvements for the delivery of nucleic acids using CPP-conjugated chitosan-based carriers with special emphasis on plasmid DNA and small interfering RNA.

  11. Atomic Force Microscopy-based Cell Nanostructure for Ligand-conjugated Quantum Dot Endocytosis

    Institute of Scientific and Technical Information of China (English)

    Yun-Long PAN; Ji-Ye CAI; Li QIN; Hao WANG

    2006-01-01

    While it has been well demonstrated that quantum dots (QDs) play an important role in biological labeling both in vitro and in vivo,there is no report describing the cellular nanostructure basis of receptor-mediated endocytosis. Here, nanostructure evolution responses to the endocytosis of transferrin force microscopy (AFM). AFM-based nanostructure analysis demonstrated that the Tf-conjugated QDs were specifically and tightly bound to the cell receptors rrelated with the cell membrane receptor-mediated transduction.Consistently, confocal microscopic and flow cytometry results have demonstrated the specificity and the internalization of Tf-QD is linearly related to time. Moreover, while the nanoparticles on the cell membrane increased, the endocytosis was still nanoparticles did not interfere sterically with the binding and function of receptors. Therefore, ligand-conjugated QDs are potentially useful in biological labeling of cells at a nanometer scale.

  12. A palmitoyl conjugate of insect pentapeptide Yamamarin arrests cell proliferation and respiration

    OpenAIRE

    2010-01-01

    A palmitoyl conjugate of an insect pentapeptide that occurs in diapausing insects causes a reversible cell-cycle arrest and suppresses mitochondrial respiration. This peptide compound also causes growth arrest in murine leukemic cell line expressing human gene Bcr/Abl and a farnesoyl peptide induces embryonic diapause in Bombyx mori. These results demonstrate that the insect peptide compounds can lead to the understanding of a common pathway in developmental arrest in animals and may provide ...

  13. Flow Cytometric Measurement of [Ca2+]i and pHi in Conjugated Natural Killer Cells and K562 Target Cells during the Cytotoxic Process1,2

    NARCIS (Netherlands)

    van Graft, Marja; van Graft, M.; Kraan, Yvonne M.; Segers-Nolten, Gezina M.J.; Radosevic, K.; Radosevic, Katarina; de Grooth, B.G.; Greve, Jan

    1993-01-01

    We describe a flow cytometric assay that enables one to follow conjugate formation between cytotoxic cells and their target cells during the cytotoxic process. In addition, the internal calcium concentration ([Ca2+]i) and internal pH (pHi) of the conjugated cells can be monitored and directly

  14. Cytotoxic activity of G3 PAMAM-NH₂ dendrimer-chlorambucil conjugate in human breast cancer cells.

    Science.gov (United States)

    Bielawski, Krzysztof; Bielawska, Anna; Muszyńska, Anna; Popławska, Bożena; Czarnomysy, Robert

    2011-11-01

    Evaluation of the cytotoxicity of a novel G3 PAMAM-NH(2) dendrimer-chlorambucil conjugate employing a MTT assay and inhibition of [(3)H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that the conjugate was more potent antiproliferative agent than chlorambucil. It was found that dendrimer-chlorambucil conjugate was more active inhibitor of collagen biosynthesis than chlorambucil. Our experiments carried out with flow cytometry assessment of annexin V binding and fluorescent microscopy assay revealed that PAMAM-CH conjugate inhibited the proliferation of MCF-7 and MDA-231 malignant cells by increasing the number of apoptotic and necrotic cells. The apoptotic effect of PAMAM-CH conjugate was found to be stronger than that caused by chlorambucil. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Parallel synthesis and splicing redirection activity of cell-penetrating peptide conjugate libraries of a PNA cargo

    NARCIS (Netherlands)

    Deuss, Peter J.; Arzumanov, Andrey A.; Williams, Donna L.; Gait, Michael J.

    2013-01-01

    A novel method for the parallel synthesis of peptide-biocargo conjugates was developed that utilizes affinity purification for fast isolation of the conjugates in order to avoid time consuming HPLC purification. The methodology was applied to create two libraries of cell-penetrating peptide (CPP)-PN

  16. Comparison of anti-EGFR-Fab’ conjugated immunoliposomes modified with two different conjugation linkers for siRNA delivery in SMMC-7721 cells

    Directory of Open Access Journals (Sweden)

    Deng L

    2013-08-01

    Full Text Available Li Deng,1,* Yingying Zhang,1,* Lulu Ma,1,5,* Xiaolong Jing,1,3 Xingfa Ke,1,3 Jianhao Lian,1,3 Qiang Zhao,1,3 Bo Yan,1,3 Jinfeng Zhang,4 Jianzhong Yao,2 Jianming Chen1 1Department of Pharmaceutical Science, 2Department of Medicinal Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, People’s Republic of China; 3Department of Pharmacy, Fujian University of Traditional Chinese Medicine, Fujian, People’s Republic of China; 4Shanghai TCM Integrated Hospital, Shanghai, People’s Republic of China; 5Department of Pharmacy, First Affiliated Hospital of Bengbu Medical College, Bengbu, People’s Republic of China *These authors contributed equally to this paper Background: Targeted liposome-polycation-DNA complex (LPD, mainly conjugated with antibodies using functionalized PEG derivatives, is an effective nanovector for systemic delivery of small interference RNA (siRNA. However, there are few studies reporting the effect of different conjugation linkers on LPD for gene silencing. To clarify the influence of antibody conjugation linkers on LPD, we prepared two different immunoliposomes to deliver siRNA in which DSPE-PEG-COOH and DSPE-PEG-MAL, the commonly used PEG derivative linkers, were used to conjugate anti-EGFR Fab’ with the liposome. Methods: First, 600 µg of anti-EGFR Fab’ was conjugated with 28.35 µL of a micelle solution containing DSPE-PEG-MAL or DSPE-PEG-COOH, and then post inserted into the prepared LPD. Various liposome parameters, including particle size, zeta potential, stability, and encapsulation efficiency were evaluated, and the targeting ability and gene silencing activity of TLPD-FPC (DSPE-PEG-COOH conjugated with Fab’ was compared with that of TLPD-FPM (DSPE-PEG-MAL conjugated with Fab’ in SMMC-7721 hepatocellular carcinoma cells. Results: There was no significant difference in particle size between the two TLPDs, but the zeta potential was significantly different. Further, although there was

  17. Synthesis and characterization of jacalin-gold nanoparticles conjugates as specific markers for cancer cells.

    Science.gov (United States)

    Marangoni, Valeria S; Paino, Ieda M; Zucolotto, Valtencir

    2013-12-01

    New nanobiocomposites that combine nanoparticles and biomolecules have been shown very relevant for medical applications. Recently, cancer diagnostics and treatment have benefited from the development of nanobiocomposites, in which metallic or magnetic nanoparticles are conjugated with specific biomolecules for selective cell uptake. Despite recent advances in this area, the biomedical applications of these materials are still limited by the low efficiency of functionalization, low stability, among other factors. In this study, we report the synthesis of jacalin-conjugated gold nanoparticles, a nanoconjugate with potential application in medical areas, especially for cancer diagnosis. Jacalin is a lectin protein and it was employed due to its ability to recognize the Galβ1-3GalNAc disaccharide, which is highly expressed in tumor cells. Gold nanoparticles (AuNPs) were synthesized in the presence of generation 4 polyamidoamine dendrimer (PAMAM G4) and conjugated with fluorescein isothiocyanate (FITC)-labeled jacalin. The AuNPs/jacalin nanoconjugates were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and vibrational spectroscopy (FTIR). We also performed an investigation using isothermal titration calorimetry (ITC) and fluorescence quenching measurements to understand the interactions occurring between the AuNPs and jacalin, which revealed that the nanoconjugate formation is driven by an entropic process with good affinity. Furthermore, in vitro tests revealed that the AuNPs/jacalin-FITC nanoconjugates exhibited higher affinity for leukemic K562 cells than for healthy mononuclear blood cells, which could be useful for biomedical applications, including cancer cells imaging.

  18. Targeting of follicle stimulating hormone peptide-conjugated dendrimers to ovarian cancer cells

    Science.gov (United States)

    Modi, Dimple A.; Sunoqrot, Suhair; Bugno, Jason; Lantvit, Daniel D.; Hong, Seungpyo; Burdette, Joanna E.

    2014-02-01

    Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side effects. To address these issues, we have designed poly(amidoamine) (PAMAM) dendrimers to selectively target the follicle stimulating hormone receptor (FSHR), which is overexpressed by tumorigenic ovarian cancer cells but not by immature primordial follicles and other non-tumorigenic cells. Fluorescein-labeled generation 5 (G5) PAMAM dendrimers were conjugated with the binding peptide domain of FSH (FSH33) that has a high affinity to FSHR. The targeted dendrimers exhibited high receptor selectivity to FSHR-expressing OVCAR-3 cells, resulting in significant uptake and downregulation of an anti-apoptotic protein survivin, while showing minimal interactions with SKOV-3 cells that do not express FSHR. The selectivity of the FSH33-targeted dendrimers was further validated in 3D organ cultures of normal mouse ovaries. Immunostaining of the conjugates revealed their selective binding and uptake by ovarian surface epithelium (OSE) cells that express FSHR, while sparing the immature primordial follicles. In addition, an in vivo study monitoring tissue accumulation following a single intraperitoneal (i.p.) injection of the conjugates showed significantly higher accumulation of FSH33-targeted dendrimers in the ovary and oviduct compared to the non-targeted conjugates. These proof-of-concept findings highlight the potential of these FSH33-targeted dendrimers to serve as a delivery platform for anti-ovarian cancer drugs, while reducing their systemic side effects by preventing nonspecific uptake by the primordial follicles.Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side

  19. Dual stimuli polysaccharide nanovesicles for conjugated and physically loaded doxorubicin delivery in breast cancer cells

    Science.gov (United States)

    Pramod, P. S.; Shah, Ruchira; Jayakannan, Manickam

    2015-04-01

    The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the administration of doxorubicin via physical loading and polymer-drug conjugation to breast cancer cells. Dextran was suitably modified with a renewable resource 3-pentadecyl phenol unit through imine and aliphatic ester chemical linkages that acted as pH and esterase enzyme stimuli, respectively. These dual responsive polysaccharide derivatives self-organized into 200 +/- 10 nm diameter nano-vesicles in water. The water soluble anticancer drug doxorubicin (DOX.HCl) was encapsulated in the hydrophilic pocket to produce core-loaded polysaccharide vesicles whereas chemical conjugation produced DOX anchored at the hydrophobic layer of the dextran nano-vesicles. In vitro studies revealed that about 70-80% of the drug was retained under circulatory conditions at pH = 7.4 and 37 °C. At a low pH of 6.0 to 5.0 and in the presence of esterase; both imine and ester linkages were cleaved instantaneously to release 100% of the loaded drugs. Cytotoxicity assays on Wild Type Mouse Embryonic Fibroblasts (WTMEFs) confirmed the non-toxicity of the newly developed dextran derivatives at up to 500 μg mL-1 in PBS. MTT assays on fibroblast cells revealed that DOX.HCl loaded nano-vesicles exhibited better killing abilities than DOX conjugated polymer nano-vesicles. Both DOX loaded and DOX conjugated nano-vesicles were found to show significant killing in breast cancer cells (MCF 7). Confocal microscopy images confirmed the uptake of DOX loaded (or conjugated) nano-vesicles by cells compared to free DOX. Thus, the newly developed pH and enzyme dual responsive polysaccharide vesicular assemblies are potential drug vectors for the administration of DOX in both loaded and chemically conjugated forms for the efficient killing of breast cancer cells.The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the

  20. Synthesis and evaluation of the biostability and cell compatibility of novel conjugates of nucleobase, peptidic epitope, and saccharide

    Directory of Open Access Journals (Sweden)

    Dan Yuan

    2015-08-01

    Full Text Available This article reports the synthesis of a new class of conjugates containing a nucleobase, a peptidic epitope, and a saccharide and the evalution of their gelation, biostability, and cell compatibility. We demonstrate a facile synthetic process, based on solid-phase peptide synthesis of nucleopeptides, to connect a saccharide with the nucleopeptides for producing the target conjugates. All the conjugates themselves (1–8 display excellent solubility in water without forming hydrogels. However, a mixture of 5 and 8 self-assembles to form nanofibers and results in a supramolecular hydrogel. The proteolytic stabilities of the conjugates depend on the functional peptidic epitopes. We found that TTPV is proteolytic resistant and LGFNI is susceptible to proteolysis. In addition, all the conjugates are compatible to the mammalian cells tested.

  1. Albumin binding ligands and albumin conjugate uptake by cancer cells

    Directory of Open Access Journals (Sweden)

    Frei Eva

    2011-06-01

    Full Text Available Abstract The scope of this short review is to summarise the knowledge gleaned from the fate of drugs transported by albumin upon contact with the target cancer cell or cells in inflamed tissues. The authors expertise covers covalently bound drugs and their cellular uptake and release from albumin. This review therefore aims to deduce what will happen to drugs such as insulin detemir which is considered to bind non-covalently to albumin and may have a fate similar to fatty acids transported by albumin.

  2. Bacterial conjugation in the cytoplasm of mouse cells.

    NARCIS (Netherlands)

    Lim, Y.M.; Groof, A.J.C. de; Bhattacharjee, M.K.; Figurski, D.H.; Schon, E.A.

    2008-01-01

    Intracellular pathogenic organisms such as salmonellae and shigellae are able to evade the effects of many antibiotics because the drugs are not able to penetrate the plasma membrane. In addition, these bacteria may be able to transfer genes within cells while protected from the action of drugs. The

  3. Photochemical Stability of π-Conjugated Polymers for Polymer Solar Cells: a Rule of Thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu

    2010-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. More than 20 samples were selected to cover a broad variety of polymer types (purely donor, donor / acceptor, thermo-cleavable) and chemical structures. Many of the m......A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. More than 20 samples were selected to cover a broad variety of polymer types (purely donor, donor / acceptor, thermo-cleavable) and chemical structures. Many....... Polymer durability was shown to cover a very broad range of values, from very few hours (e.g. MEH-PPV) to several thousands of hours (e.g. some thermo-cleaved samples). As all the experiments were conducted under the same conditions, comparison of the collected data was possible and the influence...

  4. Folic acid-CdTe quantum dot conjugates and their applications for cancer cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Suriamoorthy, Preethi; Zhang, Xing; Hao, Guiyang; Joly, Alan G.; Singh, S.; Hossu, Marius; Sun, Xiankai; Chen, Wei

    2010-12-01

    In this study, we report the preparation,luminescence, and targeting properties of folic acid- CdTe quantum dot conjugates. Water-soluble CdTe quantum dots were synthesized and conjugated with folic acid using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-N-hydroxysuccinimide chemistry. The in-fluence of folic acid on the luminescence properties of CdTe quantum dots was investigated, and no energy transfer between them was observed. To investigate the efficiency of folic acid-CdTe nanoconjugates for tumor targeting, pure CdTe quantum dots and folic acid-coated CdTe quantum dots were incubated with human naso- pharyngeal epidermal carcinoma cell line with positive expressing folic acid receptors (KB cells) and lung cancer cells without expression of folic acid receptors (A549 cells). For the cancer cells with positive folate receptors (KB cells), the uptake for CdTe quantum dots is very low, but for folic acid-CdTe nanoconjugates, the uptake is very high. For the lung cancer cells without folate receptors (A549 cells), the uptake for folic acid- CdTe nanoconjugates is also very low. The results indicate that folic acid is an effective targeting molecule for tumor cells with overexpressed folate receptors.

  5. Improved drug targeting of cancer cells by utilizing actively targetable folic acid-conjugated albumin nanospheres.

    Science.gov (United States)

    Shen, Zheyu; Li, Yan; Kohama, Kazuhiro; Oneill, Brian; Bi, Jingxiu

    2011-01-01

    Folic acid-conjugated albumin nanospheres (FA-AN) have been developed to provide an actively targetable drug delivery system for improved drug targeting of cancer cells with reduced side effects. The nanospheres were prepared by conjugating folic acid onto the surface of albumin nanospheres using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as a catalyst. To test the efficacy of these nanospheres as a potential delivery platform, doxorubicin-loaded albumin nanospheres (DOX-AN) and doxorubicin-loaded FA-AN (FA-DOX-AN) were prepared by entrapping DOX (an anthracycline, antibiotic drug widely used in cancer chemotherapy that works by intercalating DNA) into AN and FA-AN nanoparticles. Cell uptake of the DOX was then measured. The results show that FA-AN was incorporated into HeLa cells (tumor cells) only after 2.0h incubation, whereas HeLa cells failed to incorporate albumin nanospheres without conjugated folic acid after 4.0h incubation. When HeLa cells were treated with the DOX-AN, FA-DOX-AN nanoparticles or free DOX, cell viability decreased with increasing culture time (i.e. cell death increases with time) over a 70h period. Cell viability was always the lowest for free DOX followed by FA-DOX-AN4 and then DOX-AN. In a second set of experiments, HeLa cells washed to remove excess DOX after an initial incubation for 2h were incubated for 70h. The corresponding cell viability was slightly higher when the cells were treated with FA-DOX-AN or free DOX whilst cells treated with DOX-AN nanoparticles remained viable. The above experiments were repeated for non-cancerous, aortic smooth muscle cells (AoSMC). As expected, cell viability of the HeLa cells (with FA receptor alpha, FRα) and AoSMC cells (without FRα) decreased rapidly with time in the presence of free DOX, but treatment with FA-DOX-AN resulted in selective killing of the tumor cells. These results indicated that FA-AN may be used as a promising actively targetable drug delivery system to improve drug

  6. Synthesis, spectroscopic, and photophysical characterization and photosensitizing activity toward prokaryotic and eukaryotic cells of porphyrin-magainin and -buforin conjugates.

    Science.gov (United States)

    Dosselli, Ryan; Ruiz-González, Rubén; Moret, Francesca; Agnolon, Valentina; Compagnin, Chiara; Mognato, Maddalena; Sella, Valentina; Agut, Montserrat; Nonell, Santi; Gobbo, Marina; Reddi, Elena

    2014-02-27

    Cationic antimicrobial peptides (CAMPs) and photodynamic therapy (PDT) are attractive tools to combat infectious diseases and to stem further development of antibiotic resistance. In an attempt to increase the efficiency of bacteria inactivation, we conjugated a PDT photosensitizer, cationic or neutral porphyrin, to a CAMP, buforin or magainin. The neutral and hydrophobic porphyrin, which is not photoactive per se against Gram-negative bacteria, efficiently photoinactivated Escherichia coli after conjugation to either buforin or magainin. Conjugation to magainin resulted in the considerable strengthening of the cationic and hydrophilic porphyrin's interaction with the bacterial cells, as shown by the higher bacteria photoinactivation activity retained after washing the bacterial suspension. The porphyrin-peptide conjugates also exhibited strong interaction capability as well as photoactivity toward eukaryotic cells, namely, human fibroblasts. These findings suggest that these CAMPs have the potential to carry drugs and other types of cargo inside mammalian cells similar to cell-penetrating peptides.

  7. Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

    DEFF Research Database (Denmark)

    Toušek, J.; Toušková, J.; Remeš, Z.;

    2015-01-01

    Measurements of electrical conductivity, electron work function, carrier mobility ofholes and the diffusion length of excitons were performed on samples of conjugatedpolymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazolebased conjugated copolymer (PBDTTHD − DTBTff...

  8. Fluorescence and confocal imaging of mammalian cells using conjugated oligoelectrolytes with phenylenevinylene core

    Energy Technology Data Exchange (ETDEWEB)

    Milczarek, Justyna; Pawlowska, Roza; Zurawinski, Remigiusz; Lukasik, Beata; Garner, Logan E.; Chworos, Arkadiusz

    2017-05-01

    Over the last few years, considerable efforts are taken, in order to find a molecular fluorescent probe fulfilling their applicability requirements. Due to a good optical properties and affinity to biological structures conjugated oligoelectrolytes (COEs) can be considered as a promising dyes for application in fluorescence-based bioimaging. In this work, we synthetized COEs with phenylenevinylene core (PV-COEs) and applied as fluorescent membranous-specific probes. Cytotoxicity effects of each COE were probed on cancerous and non-cancerous cell types and little to no toxicity effects were observed at the high range of concentrations. The intensity of cell fluorescence following the COE staining was determined by the photoluminescence analysis and fluorescence activated cell sorting method (FACS). Intercalation of tested COEs into mammalian cell membranes was revealed by fluorescent and confocal microscopy colocalization with commercial dyes specific for cellular structures including mitochondria, Golgi apparatus and endoplasmic reticulum. The phenylenevinylene conjugated oligoelectrolytes have been found to be suitable for fluorescent bioimaging of mammalian cells and membrane-rich organelles. Due to their water solubility coupled with spontaneous intercalation into cells, favorable photophysical features, ease of cell staining, low cytotoxicity and selectivity for membranous structures, PV-COEs can be applied as markers for fluorescence imaging of a variety of cell types.

  9. Development of Viral Capsid DNA Aptamer Conjugates as Cell-Targeted Delivery Vehicles

    Science.gov (United States)

    Tong, Gary Jen-Wei

    The ability to generate semi-synthetic DNA-protein conjugates has become increasingly important in the fields of chemical biology and nanobiotechnology. As applications in these fields become more complex, there is also an increased need for methods of attaching synthetic DNA to protein substrates in a well-defined manner. This work outlines the development of new methods for site-specific DNA-protein bioconjugation, as well as the development of novel viral capsid DNA aptamer conjugates for cell-targeting purposes. In order to generate DNA-protein conjugates in a site-specific manner, chemistries orthogonal to native functional groups present on DNA and proteins were exploited. In one method, the attachment of DNA to proteins was achieved via oxime formation. This strategy involved the in situ deprotection of an allyloxycarbonyl-protected alkoxyamine-bearing DNA in the presence of a protein containing a single ketone group. The utility of this approach was demonstrated in the synthesis of a DNA-GFP conjugate. In addition to the oxime formation route, two oxidative coupling methods were also developed for DNA-protein bioconjugation. The first reaction coupled phenylenediamine-containing DNA to anilines, which had been site-specifically incorporated into proteins, in the presence of NaIO4. These reaction conditions were demonstrated on the proteins bacteriophage MS2 and GFP, and were mild enough for the components to retain both protein structure and DNA base-pairing capabilities. The second oxidative coupling reaction conjugated aniline-containing proteins to DNA bearing an o-aminophenol moiety. This reaction occurred under similarly mild conditions; however, higher coupling yields were achieved on MS2 at shorter reaction times by using this strategy. In all three of these methods, the generation of a singly-modified product was achieved. Using one of our oxidative coupling strategies, MS2-DNA aptamer conjugates were synthesized for the development of multivalent

  10. Donor-acceptor conjugated polymers based on multifused ladder-type arenes for organic solar cells.

    Science.gov (United States)

    Wu, Jhong-Sian; Cheng, Sheng-Wen; Cheng, Yen-Ju; Hsu, Chain-Shu

    2015-03-07

    Harvesting solar energy from sunlight to generate electricity is considered as one of the most important technologies to address the future sustainability of humans. Polymer solar cells (PSCs) have attracted tremendous interest and attention over the past two decades due to their potential advantage to be fabricated onto large area and light-weight flexible substrates by solution processing at a lower cost. PSCs based on the concept of bulk heterojunction (BHJ) configuration where an active layer comprises a composite of a p-type (donor) and an n-type (acceptor) material represents the most useful strategy to maximize the internal donor-acceptor interfacial area allowing for efficient charge separation. Fullerene derivatives such as [6,6]-phenyl-C61 or 71-butyric acid methyl ester (PCBM) are the ideal n-type materials ubiquitously used for BHJ solar cells. The major effort to develop photoactive materials is numerously focused on the p-type conjugated polymers which are generally synthesized by polymerization of electron-rich donor and electron-deficient acceptor monomers. Compared to the development of electron-deficient comonomers (acceptor segments), the development of electron-rich donor materials is considerably flourishing. Forced planarization by covalently fastening adjacent aromatic and heteroaromatic subunits leads to the formation of ladder-type conjugated structures which are capable of elongating effective conjugation, reducing the optical bandgap, promoting intermolecular π-π interactions and enhancing intrinsic charge mobility. In this review, we will summarize the recent progress on the development of various well-defined new ladder-type conjugated materials. These materials serve as the superb donor monomers to prepare a range of donor-acceptor semi-ladder copolymers with sufficient solution-processability for solar cell applications.

  11. PE-Cy5.5 conjugates bind to the cells expressing mouse DEC205/CD205

    Science.gov (United States)

    Park, Chae Gyu; Rodriguez, Anthony; Steinman, Ralph M.

    2012-01-01

    DEC205/CD205, an endocytic receptor of C-type multilectin, is expressed highly in dendritic cells (DCs). DEC205 was shown to efficiently deliver vaccine antigens in surrogate ligands to the antigen processing and presentation machinery of DCs, which resulted in the development of DC-targeted vaccines employing anti-DC monoclonal antibodies (mAbs). During our studies to characterize a variety of anti-DC mAbs including anti-DEC205 by flow cytometric analysis, we discovered that a secondary anti-immunoglobulin antibody conjugated with PE-Cy5.5 bound strongly to the cells expressing mouse DEC205 (mDEC205) without incubation of a primary anti-mDEC205 mAb. In the present study we demonstrate that various antibodies and streptavidin conjugated with PE-Cy5.5 bind to the mDEC205-expressing cells including CHO, KIT6, and HEK293 cells. The interaction between the PE-Cy5.5 conjugates and the cells expressing mDEC205 appears distinctive, since none of PE-Cy5.5 conjugates bind to the cells that express human DEC205 on surface. Besides, only PE-Cy5.5 conjugates bind strongly to mDEC205-expressing cells; PerCP-Cy5.5, APC-Cy5.5, and Cy5.5 conjugates bind weakly; PE, PE-Cy5, Cy5, FITC, or Alexa488 conjugates do not bind. Therefore the use of PE-Cy5.5 conjugates, widely utilized in multicolor flow cytometry, requires precaution against nonspecific binding to mDEC205-positive cells. PMID:22841832

  12. Use of Baicalin-Conjugated Gold Nanoparticles for Apoptotic Induction of Breast Cancer Cells

    Science.gov (United States)

    Lee, Donghyun; Ko, Wan-Kyu; Hwang, Deok-Sang; Heo, Dong Nyoung; Lee, Sang Jin; Heo, Min; Lee, Kook-Sun; Ahn, Ji-Yoon; Jo, Junyoung; Kwon, Il Keun

    2016-08-01

    Baicalin (BC) has been used for cancer therapy due to its multiple effects as an anti-cancer drug. However, the effective delivery of this molecule to targeted cells is difficult. Gold nanoparticles (AuNPs) conjugated with thiolated beta cyclodextrin (AuNP-S-β-CD) were used as a delivery vector in this study. Cell viability tests were evaluated by cell counting kit-8 (CCK) and live/dead cell assay. To demonstrate the proliferation inhibition effect on Michigan Cancer Foundation-7 (MCF-7) cells by BC, we analyzed using Hoechst 33342 staining assay and gel electrophoresis. The S-β-CD conjugated AuNPs were characterized by transmission electron microscopy (TEM), 1H nuclear magnetic resonance (1H NMR), and ultraviolet visible (UV-vis) spectroscopy. AuNP-S-β-CD with approximately 40 μM of BC loaded by inclusion complex showed an inhibition effect on MCF-7 cells by inducing apoptosis. Apoptosis test results were evaluated by analyzing the expression of typical apoptic markers such as cleaved caspase-3, full length caspase-3, and apaf-1 in western blot assay. These results demonstrated that AuNP-S-β-CD-BC inhibited the proliferation of cancerous MCF-7 cells by inducing apoptosis. These findings suggested that AuNP-S-β-CD-BC could be a promising agent for chemotherapeutic usage.

  13. Dengue virus-specific CD4+ and CD8+ T lymphocytes target NS1, NS3 and NS5 in infected Indian rhesus macaques.

    Science.gov (United States)

    Mladinich, Katherine M; Piaskowski, Shari M; Rudersdorf, Richard; Eernisse, Christopher M; Weisgrau, Kim L; Martins, Mauricio A; Furlott, Jessica R; Partidos, Charalambos D; Brewoo, Joseph N; Osorio, Jorge E; Wilson, Nancy A; Rakasz, Eva G; Watkins, David I

    2012-02-01

    Every year, Dengue virus (DENV) infects approximately 100 million people. There are currently several vaccines undergoing clinical studies, but most target the induction of neutralizing antibodies. Unfortunately, DENV infection can be enhanced by subneutralizing levels of antibodies that bind virions and deliver them to cells of the myeloid lineage, thereby increasing viral replication (termed antibody-dependent enhancement [ADE]). T lymphocyte-based vaccines may offer an alternative that avoids ADE. The goal of our study was to describe the cellular immune response generated after primary DENV infection in Indian rhesus macaques. We infected eight rhesus macaques with 10⁵ plaque-forming units (PFU) of DENV serotype 2 (DENV2) New Guinea C (NGC) strain, and monitored viral load and the cellular immune response to the virus. Viral replication peaked at day 4 post-infection and was resolved by day 10. DENV-specific CD4+ and CD8+ T lymphocytes targeted nonstructural (NS) 1, NS3 and NS5 proteins after resolution of peak viremia. DENV-specific CD4+ cells expressed interferon-gamma (IFN-γ) along with tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), and macrophage inflammatory protein-1 beta (MIP-1β). In comparison, DENV-specific CD8+ cells expressed IFN-γ in addition to MIP-1β and TNF-α and were positive for the degranulation marker CD107a. Interestingly, a fraction of the DENV-specific CD4+ cells also stained for CD107a, suggesting that they might be cytotoxic. Our results provide a more complete understanding of the cellular immune response during DENV infection in rhesus macaques and contribute to the development of rhesus macaques as an animal model for DENV vaccine and pathogenicity studies.

  14. Cell cycle-dependent SUMO-1 conjugation to nuclear mitotic apparatus protein (NuMA)

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jae Sung; Kim, Ha Na; Kim, Sun-Jick; Bang, Jiyoung; Kim, Eun-A; Sung, Ki Sa [Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Yoon, Hyun-Joo [TissueGene Inc. 9605 Medical Center Dr., Rockville, MD 20850 (United States); Yoo, Hae Yong [Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of); Choi, Cheol Yong, E-mail: choicy@skku.ac.kr [Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-01-03

    Highlights: •NuMA is modified by SUMO-1 in a cell cycle-dependent manner. •NuMA lysine 1766 is the primary target site for SUMOylation. •SUMOylation-deficient NuMA induces multiple spindle poles during mitosis. •SUMOylated NuMA induces microtubule bundling. -- Abstract: Covalent conjugation of proteins with small ubiquitin-like modifier 1 (SUMO-1) plays a critical role in a variety of cellular functions including cell cycle control, replication, and transcriptional regulation. Nuclear mitotic apparatus protein (NuMA) localizes to spindle poles during mitosis, and is an essential component in the formation and maintenance of mitotic spindle poles. Here we show that NuMA is a target for covalent conjugation to SUMO-1. We find that the lysine 1766 residue is the primary NuMA acceptor site for SUMO-1 conjugation. Interestingly, SUMO modification of endogenous NuMA occurs at the entry into mitosis and this modification is reversed after exiting from mitosis. Knockdown of Ubc9 or forced expression of SENP1 results in impairment of the localization of NuMA to mitotic spindle poles during mitosis. The SUMOylation-deficient NuMA mutant is defective in microtubule bundling, and multiple spindles are induced during mitosis. The mitosis-dependent dynamic SUMO-1 modification of NuMA might contribute to NuMA-mediated formation and maintenance of mitotic spindle poles during mitosis.

  15. Structure-property relationships of small bandgap conjugated polymers for solar cells.

    Science.gov (United States)

    Hellström, Stefan; Zhang, Fengling; Inganäs, Olle; Andersson, Mats R

    2009-12-01

    Conjugated polymers as electron donors in solar cells based on donor/acceptor combinations are of great interest, partly due to the possibility of converting solar light with a low materials budget. Six small bandgap polymers with optical bandgap ranging from 1.0-1.9 eV are presented in this paper. All polymers utilize an electron donor-acceptor-donor (DAD) segment in the polymer backbone, creating a partial charge-transfer, to decrease the bandgap. The design, synthesis and the optical characteristics as well as the solar cell characteristics of the polymers are discussed. The positions of the energy levels of the conjugated polymer relative to the electron acceptor are of significant importance and determine not only the driving force for exciton dissociation but also the maximum open-circuit voltage. This work also focuses on investigating the redox behavior of the described conjugated polymers and electron acceptors using square wave voltammetry. Comparing the electrochemical data gives important information of the structure-property relationships of the polymers.

  16. Tumor cell apoptosis induced by nanoparticle conjugate in combination with radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang Li; Yang Wensha; Read, Paul; Larner, James; Sheng Ke, E-mail: Ks2mc@virginia.edu [Department of Radiation Oncology, University of Virginia (United States)

    2010-11-26

    Semiconductor nanoparticles conjugated to photosensitizers have been shown to increase tumor cell death with ionizing radiation but the mechanism, particularly the role of photodynamic therapy in the process, was unknown. We used a molecular probe to measure production of {sup 1}O{sub 2} to quantify the component of photodynamic cell-killing in an in vitro system. The intracellular distribution of the nanoparticle conjugate (NC) was determined by the co-localization of nanoparticles and the lysotracker. Induction of apoptosis was measured by the TUNEL assay and western blot analysis of the cleaved caspase-3. As a result, dose-dependent {sup 1}O{sub 2} production was observed with 48 nm NC after irradiating with 6 MV x-rays. A high geometrical coincidence between the fluorescence emission of the nanoparticle and lysotracker was observed using confocal microscopy. Finally, apoptosis, as indicated by the TUNEL stain and cleavage of the caspase-3, was observed in cells treated by both the NC and 6 Gy of radiation but not in cells treated with radiation alone. In conclusion, the cell death induced by the NC in combination with radiation is consistent with a supra-additive effect to radiation-or NC-alone-killing and is mediated by an NC-induced photodynamic therapy mechanism, which is distinctly different from that for radiation-killing alone. By providing a second distinct cell-killing mechanism, this nanoparticle conjugate has great promise as a targeted physical radiosensitizer aimed at overcoming radioresistant tumor clonogens or/and reducing normal tissue toxicity by using a lower ionizing radiation dose.

  17. Methotrexate-conjugated quantum dots: synthesis, characterisation and cytotoxicity in drug resistant cancer cells.

    Science.gov (United States)

    Johari-Ahar, Mohammad; Barar, Jaleh; Alizadeh, Ali Mohammad; Davaran, Soodabeh; Omidi, Yadollah; Rashidi, Mohammad-Reza

    2016-01-01

    Methotrexate (MTX), a folic acid derivative, is a potent anticancer used for treatment of different malignancies, but possible initiation of drug resistance to MTX by cancer cells has limited its applications. Nanoconjugates (NCs) of MTX to quantum dots (QDs) may favour the cellular uptake via folate receptors (FRs)-mediated endocytosis that circumvents the efflux functions of cancer cells. We synthesised MTX-conjugated l-cysteine capped CdSe QDs (MTX-QD nanoconjugates) and evaluated their internalisation and cytotoxicity in the KB cells with/without resistancy to MTX. The NCs were fully characterised by high resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and optical spectroscopy. Upon conjugation with MTX, the photoluminescence (PL) properties of QDs altered, while an obvious quenching in PL of QDs was observed after physical mixing. The MTX-QD nanoconjugates efficiently internalised into the cancer cells, and induced markedly high cytotoxicity (IC50, 12.0 µg/mL) in the MTX-resistant KB cells as compared to the free MTX molecules (IC50,105.0 µg/mL), whereas, these values were respectively about 7.0 and 0.6 µg/mL in the MTX-sensitive KB cells. Based on these findings, the MTX-QD nanoconjugates are proposed for the targeted therapy of MTX-resistant cancers, which may provide an improved outcome in the relapsed FR-overexpressing cancers.

  18. Prednisolone succinate-glucosamine conjugate: Synthesis, characterization and in vitro cellular uptake by kidney cell lines

    Institute of Scientific and Technical Information of China (English)

    Yan Lin; Xun Sun; Tao Gong; Zhi Rong Zhang

    2012-01-01

    Prednisolone succinate-glucosamine (PSG) conjugate,a prodrug for prednisolone,was synthesized and confirmed by NMR and MS spectrum.The stabilities of the prodrug in PBS (pH 2.50,5.00,7.20,and 7.89) were studied.Cytotoxicity and uptake assay of the prodrug were perfomed on HK-2 and MDCK cell lines.The results showed that compared with prednisolone,the PSG not only did not increase the cytotoxicity but also improved the uptake to 2.2 times of prednisolone by the cells.Thus,it indicated that glucosamine might be a potential carrier for kidney-targeting delivery of prednisolone.

  19. A palmitoyl conjugate of insect pentapeptide Yamamarin arrests cell proliferation and respiration.

    Science.gov (United States)

    Sato, Yosinori; Yang, Ping; An, Ying; Matsukawa, Kazushige; Ito, Kikukatsu; Imanishi, Shigeo; Matsuda, Hirokazu; Uchiyama, Yusuke; Imai, Kunio; Ito, Shigeki; Ishida, Yoji; Suzuki, Koichi

    2010-05-01

    A palmitoyl conjugate of an insect pentapeptide that occurs in diapausing insects causes a reversible cell-cycle arrest and suppresses mitochondrial respiration. This peptide compound also causes growth arrest in murine leukemic cell line expressing human gene Bcr/Abl and a farnesoyl peptide induces embryonic diapause in Bombyx mori. These results demonstrate that the insect peptide compounds can lead to the understanding of a common pathway in developmental arrest in animals and may provide a new peptidominetic analog in the development of biopharmaceuticals and pest management.

  20. Role of isothiocyanate conjugate of pterostilbene on the inhibition of MCF-7 cell proliferation and tumor growth in Ehrlich ascitic cell induced tumor bearing mice

    Energy Technology Data Exchange (ETDEWEB)

    Nikhil, Kumar; Sharan, Shruti; Chakraborty, Ajanta [Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India); Bodipati, Naganjaneyulu; Krishna Peddinti, Rama [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India); Roy, Partha, E-mail: paroyfbs@iitr.ernet.in [Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India)

    2014-01-15

    Naturally occurring pterostilbene (PTER) and isothiocyanate (ITC) attract great attention due to their wide range of biological properties, including anti-cancer, anti-leukemic, anti-bacterial and anti-inflammatory activities. A novel class of hybrid compound synthesized by introducing an ITC moiety on PTER backbone was evaluated for its anti-cancer efficacy in hormone-dependent breast cancer cell line (MCF-7) in vitro and Ehrlich ascitic tumor bearing mice model in vivo. The novel hybrid molecule showed significant in vitro anti-cancer activity (IC{sub 50}=25±0.38) when compared to reference compound PTER (IC{sub 50}=65±0.42). The conjugate molecule induced both S and G2/M phase cell cycle arrest as indicated by flow cytometry analysis. In addition, the conjugate induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-9, release of cytochrome-c into cytosol and increased Bax: Bcl-2 ratio. The conjugate also suppressed the phosphorylation of Akt and ERK. The conjugate induced cell death was significantly increased in presence of A6730 (a potent Akt1/2 kinase inhibitor) and PD98059 (a specific ERK inhibitor). Moreover, the conjugated PTER inhibited tumor growth in Ehrlich ascitic cell induced tumor bearing mice as observed by reduction in tumor volume compared to untreated animals. Collectively, the pro-apoptotic effect of conjugate is mediated through the activation of caspases, and is correlated with the blockade of the Akt and ERK signaling pathways in MCF-7 cells. - Highlights: • Conjugate was prepared by appending isothiocyanate moiety on pterostilbene backbone. • Conjugate showed anticancer effects at comparatively lower dose than pterostilbene. • Conjugate caused blockage of the Akt and ERK signaling pathways in MCF-7 cells. • Conjugate significantly reduced solid tumor volume as compared to pterostilbene.

  1. Parallel synthesis of cell-penetrating peptide conjugates of PMO toward exon skipping enhancement in Duchenne muscular dystrophy.

    Science.gov (United States)

    O'Donovan, Liz; Okamoto, Itaru; Arzumanov, Andrey A; Williams, Donna L; Deuss, Peter; Gait, Michael J

    2015-02-01

    We describe two new methods of parallel chemical synthesis of libraries of peptide conjugates of phosphorodiamidate morpholino oligonucleotide (PMO) cargoes on a scale suitable for cell screening prior to in vivo analysis for therapeutic development. The methods represent an extension of the SELection of PEPtide CONjugates (SELPEPCON) approach previously developed for parallel peptide-peptide nucleic acid (PNA) synthesis. However, these new methods allow for the utilization of commercial PMO as cargo with both C- and N-termini unfunctionalized. The synthetic methods involve conjugation in solution phase, followed by rapid purification via biotin-streptavidin immobilization and subsequent reductive release into solution, avoiding the need for painstaking high-performance liquid chromatography purifications. The synthesis methods were applied for screening of PMO conjugates of a 16-member library of variants of a 10-residue ApoE peptide, which was suggested for blood-brain barrier crossing. In this work the conjugate library was tested in an exon skipping assay using skeletal mouse mdx cells, a model of Duchene's muscular dystrophy where higher activity peptide-PMO conjugates were identified compared with the starting peptide-PMO. The results demonstrate the power of the parallel synthesis methods for increasing the speed of optimization of peptide sequences in conjugates of PMO for therapeutic screening.

  2. A Conjugate Based on Anti-HER2 Diaffibody and Auristatin E Targets HER2-Positive Cancer Cells

    Science.gov (United States)

    Serwotka-Suszczak, Anna M.; Sochaj-Gregorczyk, Alicja M.; Pieczykolan, Jerzy; Krowarsch, Daniel; Jelen, Filip; Otlewski, Jacek

    2017-01-01

    Antibody-drug conjugates (ADCs) have recently emerged as efficient and selective cancer treatment therapeutics. Currently, alternative forms of drug carriers that can replace monoclonal antibodies are under intensive investigation. Here, a cytotoxic conjugate of an anti-HER2 (Human Epidermal Growth Factor Receptor 2) diaffibody with monomethyl-auristatin E (MMAE) is proposed as a potential anticancer therapeutic. The anti-HER2 diaffibody was based on the ZHER2:4 affibody amino acid sequence. The anti-HER2 diaffibody has been expressed as a His-tagged protein in E. coli and purified by Ni-nitrilotriacetyl (Ni-NTA) agarose chromatography. The molecule was properly folded, and the high affinity and specificity of its interaction with HER2 was confirmed by surface plasmon resonance (SPR) and flow cytometry, respectively. The (ZHER2:4)2DCS-MMAE conjugate was obtained by coupling the maleimide group linked with MMAE to cysteines, which were introduced in a drug conjugation sequence (DCS). Cytotoxicity of the conjugate was evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide MTT assay and the xCELLigence Real-Time Cell Analyzer. Our experiments demonstrated that the conjugate delivered auristatin E specifically to HER2-positive tumor cells, which finally led to their death. These results indicate that the cytotoxic diaffibody conjugate is a highly potent molecule for the treatment of various types of cancer overexpressing HER2 receptors. PMID:28216573

  3. PLGA-carbon nanotube conjugates for intercellular delivery of caspase-3 into osteosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Qingsu Cheng

    Full Text Available Cancer has arisen to be of the most prominent health care issues across the world in recent years. Doctors have used physiological intervention as well as chemical and radioactive therapeutics to treat cancer thus far. As an alternative to current methods, gene delivery systems with high efficiency, specificity, and safety that can reduce side effects such as necrosis of tissue are under development. Although viral vectors are highly efficient, concerns have arisen from the fact that viral vectors are sourced from lethal diseases. With this in mind, rod shaped nano-materials such as carbon nanotubes (CNTs have become an attractive option for drug delivery due to the enhanced permeability and retention effect in tumors as well as the ability to penetrate the cell membrane. Here, we successfully engineered poly (lactic-co-glycolic (PLGA functionalized CNTs to reduce toxicity concerns, provide attachment sites for pro-apoptotic protein caspase-3 (CP3, and tune the temporal release profile of CP3 within bone cancer cells. Our results showed that CP3 was able to attach to functionalized CNTs, forming CNT-PLGA-CP3 conjugates. We show this conjugate can efficiently transduce cells at dosages as low as 0.05 μg/ml and suppress cell proliferation up to a week with no further treatments. These results are essential to showing the capabilities of PLGA functionalized CNTs as a non-viral vector gene delivery technique to tune cell fate.

  4. Preparation of ubiquitin-conjugated proteins using an insect cell-free protein synthesis system.

    Science.gov (United States)

    Suzuki, Takashi; Ezure, Toru; Ando, Eiji; Nishimura, Osamu; Utsumi, Toshihiko; Tsunasawa, Susumu

    2010-01-01

    Ubiquitination is one of the most significant posttranslational modifications (PTMs). To evaluate the ability of an insect cell-free protein synthesis system to carry out ubiquitin (Ub) conjugation to in vitro translated proteins, poly-Ub chain formation was studied in an insect cell-free protein synthesis system. Poly-Ub was generated in the presence of Ub aldehyde (UA), a de-ubiquitinating enzyme inhibitor. In vitro ubiquitination of the p53 tumor suppressor protein was also analyzed, and p53 was poly-ubiquitinated when Ub, UA, and Mdm2, an E3 Ub ligase (E3) for p53, were added to the in vitro reaction mixture. These results suggest that the insect cell-free protein synthesis system contains enzymatic activities capable of carrying out ubiquitination. CBB-detectable ubiquitinated p53 was easily purified from the insect cell-free protein synthesis system, allowing analysis of the Ub-conjugated proteins by mass spectrometry (MS). Lys 305 of p53 was identified as one of the Ub acceptor sites using this strategy. Thus, we conclude that the insect cell-free protein synthesis system is a powerful tool for studying various PTMs of eukaryotic proteins including ubiqutination presented here.

  5. Nerve growth factor (NGF)-conjugated electrospun nanostructures with topographical cues for neuronal differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Cho, Young Il; Choi, Ji Suk; Jeong, Seo Young; Yoo, Hyuk Sang

    2010-12-01

    Mesenchymal stem cells (MSCs) were cultivated on the surface of nerve growth factor (NGF)-conjugated aligned nanofibrous meshes for neuronal differentiation. Amine-terminated poly(ethylene glycol) was conjugated to poly(ε-caprolactone) to prepare amine-functionalized block copolymers. The synthesized polymer was electrospun in a rotating drum to prepare aligned nanofibrous meshes. A nerve growth factor was chemically immobilized on the surface-exposed amine groups of the electrospun nanofibrous meshes in the aqueous phase. In vitro release profiles of the nerve growth factor were investigated for NGF-immobilized nanofibrous meshes. The conjugated nerve growth factor was not released for 7 days, while the growth factor physically adsorbed on the nanofibrous meshes showed an initial burst release. MSCs were cultivated on the NGF-conjugated nanofibrous meshes for 5 days, and total RNA was extracted from the cultivated cells. mRNA was extracted from cells for measuring expression levels of neuronal differentiation markers, including nestin, tubulin βIII and map2, in the cultivated stem cells. The conjugation of NGF significantly increased the expression levels of the marker proteins for neuron cells while physically adsorbed NGFs on nanofibrous meshes showed low expression of these marker genes. Furthermore, alignments of nanofibrous meshes clearly increased the expression levels of neuronal makers while the nanofibrous mesh without the topographical cue did not affect neuronal differentiation of the cultivated stem cells. Confocal microscopy revealed that the stem cells on the NGF-conjugated aligned nanofibrous meshes showed intense staining with antibodies against neuronal makers as well as elongated morphology compared to other groups. Thus, the NGF-conjugated nanofibrous meshes with topographical cues significantly increased the neuronal differentiation of mesenchymal stem cells in comparison to NGF-adsorbed nanofibrous meshes.

  6. In vitro photothermal destruction of neuroblastoma cells using carbon nanotubes conjugated with GD2 monoclonal antibody

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chung-Hao; Huang, Yao-Jhang; Chang, Chia-Wei; Peng, Ching-An [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Hsu, Wen-Ming, E-mail: cpeng@mtu.ed [Department of Surgery, National Taiwan University, Taipei, Taiwan (China)

    2009-08-05

    Despite aggressive multimodality therapy, most neuroblastoma-bearing patients relapse and survival rate remains poor. Exploration of alternative therapeutic modalities is needed. Carbon nanotubes (CNTs), revealing optical absorbance in the near-infrared region, warrant their merits in photothermal therapy. In order to specifically target disialoganglioside (GD2) overexpressed on the surface of neuroblastoma stNB-V1 cells, GD2 monoclonal antibody (anti-GD2) was conjugated to acidified CNTs. To examine the fate of anti-GD2 bound CNTs after incubation with stNB-V1 cells, rhodamine B was labeled on carboxylated CNTs functionalized with and without anti-GD2. Our results illustrated that anti-GD2-linked CNTs were extensively internalized by neuroblastoma cells via GD2-mediated endocytosis. In addition, we showed that anti-GD2 bound CNTs were not ingested by PC12 cells without GD2 expression. After anti-GD2 conjugated CNTs were incubated with neuroblastoma cells for 6 h and endocytosed by the cells, CNT-laden neuroblastoma cells were further irradiated with an 808 nm near-infrared (NIR) laser with intensity ramping from 0.6 to 6 W cm{sup -2} for 10 min which was then maintained at 6 W cm{sup -2} for an additional 5 min. Post-NIR laser exposure, and after being examined by calcein-AM dye, stNB-V1 cells were all found to undergo necrosis, while non-GD2 expressing PC12 cells all remained viable. Based on the in vitro study, CNTs bound with anti-GD2 have the potential to be utilized as a therapeutic thermal coupling agent that generates heat sufficient to selectively kill neuroblastoma cells under NIR laser light exposure.

  7. Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells

    Science.gov (United States)

    Choi, Hyosung; Mai, Cheng-Kang; Kim, Hak-Beom; Jeong, Jaeki; Song, Seyeong; Bazan, Guillermo C.; Kim, Jin Young; Heeger, Alan J.

    2015-06-01

    Organic-inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic PEDOT:PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to PEDOT:PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cells.

  8. Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide.

    Science.gov (United States)

    Brezden, Anna; Mohamed, Mohamed F; Nepal, Manish; Harwood, John S; Kuriakose, Jerrin; Seleem, Mohamed N; Chmielewski, Jean

    2016-08-31

    Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. For this significant problem to be addressed, a cleavable conjugate of the antibiotic kanamycin and a nonmembrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophages more potently than that of a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

  9. Hyaluronic acid-conjugated liposome nanoparticles for targeted delivery to CD44 overexpressing glioblastoma cells

    Science.gov (United States)

    Hayward, Stephen L.; Wilson, Christina L.; Kidambi, Srivatsan

    2016-01-01

    Glioblastoma Multiforme (GBM) is a highly prevalent and deadly brain malignancy characterized by poor prognosis and restricted disease management potential. Despite the success of nanocarrier systems to improve drug/gene therapy for cancer, active targeting specificity remains a major hurdle for GBM. Additionally, since the brain is a multi-cell type organ, there is a critical need to develop an approach to distinguish between GBM cells and healthy brain cells for safe and successful treatment. In this report, we have incorporated hyaluronic acid (HA) as an active targeting ligand for GBM. To do so, we employed HA conjugated liposomes (HALNPs) to study the uptake pathway in key cells in the brain including primary astrocytes, microglia, and human GBM cells. We observed that the HALNPs specifically target GBM cells over other brain cells due to higher expression of CD44 in tumor cells. Furthermore, CD44 driven HALNP uptake into GBM cells resulted in lysosomal evasion and increased efficacy of Doxorubicin, a model anti-neoplastic agent, while the astrocytes and microglia cells exhibited extensive HALNP-lysosome co-localization and decreased antineoplastic potency. In summary, novel CD44 targeted lipid based nanocarriers appear to be proficient in mediating site-specific delivery of drugs via CD44 receptors in GBM cells, with an improved therapeutic margin and safety. PMID:27120809

  10. Photochemical stability of π-conjugated polymers for polymer solar cells: a rule of thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu; Bundgaard, Eva; Carlé, Jon Eggert

    2011-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. The behavior of each material has been investigated under simulated sunlight (1 sun, 1000 W m−2, AM 1.5G) and ambient atmosphere. Degradation was monitored during age...... ageing combining UV-visible and infrared spectroscopies. From the comparison of the collected data, the influence of the polymer chemical structure on its stability has been discussed. General rules relative to the polymer structure–stability relationship are proposed....

  11. Conjugation with Cationic Cell-Penetrating Peptide Increases Pulmonary Absorption of Insulin

    OpenAIRE

    Patel, Leena N.; Wang, Jeffrey; Kim, Kwang-Jin; Borok, Zea; Crandall, Edward; Shen, Wei-Chiang

    2009-01-01

    In this study, we determined if cell-penetrating peptides (CPPs) can be used to enhance the absorption rate of insulin (INS) across the alveolar epithelial barrier. Using a heterobifuctional crosslinker, INS was conjugated to a series of cationic CPPs, including Tat peptide, oligoarginine (r9) or oligolysine (k9), via disulfide bridge to a D-isoform cysteine (c) present at the N-terminal of the peptide sequence, yielding INS-cTat, INS-cr9, and INS-ck9, respectively. SDS-PAGE and MALDI-TOF mas...

  12. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    KAUST Repository

    Dimitrov, Stoichko

    2016-01-13

    The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  13. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Stoichko D. Dimitrov

    2016-01-01

    Full Text Available The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  14. Interaction of sulfonylurea-conjugated polymer with insulinoma cell line of MIN6 and its effect on insulin secretion.

    Science.gov (United States)

    Park, K H; Kim, S W; Bae, Y H

    2001-04-01

    A carboxylated derivative of sulfonylurea (SU), an insulinotropic agent, was synthesized and grafted onto a water-soluble polymer as a biospecific and stimulating polymer for insulin secretion. To evaluate the effect of the SU-conjugated polymer on insulin secretion, its solution in dimethyl sulfoxide was added to the culture of insulinoma cell line of MIN6 cells to make 10 nM of SU units in the medium and incubated for 3 h at 37 degrees C. The culture medium was conditioned with glucose concentration of 3.3 or 25 mM. To verify the specific interaction between the SU (K+ channel closer)-conjugated polymer and MIN6 cells, the cells were pretreated with diazoxide, an agonist of adenosine triphosphate-sensitive K+ channel (K+ channel opener), before adding the SU-conjugated polymer to the cell culture medium. This treatment suppressed the action of SUs on MIN6 cells. Fluorescence-labeled polymer with rodamine-B isothiocyanate was used to visualize the interactions, and we found that the labeled polymer strongly absorbed to MIN6 cells, probably owing to its specific interaction mediated by SU receptors on the cell membrane. The fluorescence intensity on the cells significantly increased with an increase in incubation time and polymer concentration. A confocal laser microscopic study further confirmed this interaction. The results from this study provided evidence that SU-conjugated copolymer stimulates insulin secretion by specific interactions of SU moieties in the polymer with MIN6 cells.

  15. PREPARATION OF CHEMICAL AND PHYSICAL CONJUGATES OF SELF-ASSEMBLING NANOPARTICLES WITH CELL-PENETRATING PEPTIDE AND DOXORUBICIN

    Directory of Open Access Journals (Sweden)

    Zhadyra Sagykyzy Shagyrova

    2015-09-01

    Full Text Available Abstract: Nano-sized carriers can help to reduce toxicity and improve clinical efficacy of drugs. Virus-like particles (VLPs are biocompatible and biodegradable self-assembling nanoparticles, which show great promise as carriers for substances for targeted delivery and controlled release. Either chemical conjugation of physical incorporation without formation of covalent bonds is possible to load substances of interest into VLPs.Objectives: To produce VLPs from recombinant viral capsid protein (HBcAg and test feasibility of methods of formation of chemical and physical conjugates of VLPs with substances of pharmacological interest.Methods: Virus-like particles composed from recombinant hepatitis B core antigen (HBcAg were produced by recombinant expression in E.coli and purified by successive centrifugation through sucrose gradients. Peptide transportan 10 was synthesized and used for carbodiimide (EDC-mediated conjugation to VLPs. Doxorubicin (DOX was loaded into the nucleic acid-containing VLPs to form physical conjugate.Results: VLPs with chemically attached moieties of cell-penetrating peptide transportan 10 were produced. The conjugate was examined in SDS-PAGE to confirm presence of conjugation products. Conjugation efficiency (molar ration peptide/protein in the conjugate reaches 0.5:1 (i.e. 50% of protein chains have one attached peptide moiety. The nucleic acid-containing VLPs can be loaded with the DOX forming stable non-covalent physical conjugate.Conclusion: Recombinantly expressed VLPs allow easy attaching of small molecules making them a convenient platform to develop drug carriers.

  16. Dual targeting of a thermosensitive nanogel conjugated with transferrin and RGD-containing peptide for effective cell uptake and drug release

    Energy Technology Data Exchange (ETDEWEB)

    Quan Changyun; Chang Cong; Wei Hua; Chen Changsheng; Xu Xiaoding; Cheng Sixue; Zhang Xianzheng; Zhuo Renxi, E-mail: xz-zhang@whu.edu.c [Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2009-08-19

    In this paper, both arginine-glycine-aspartic acid (RGD)-containing peptide and transferrin (Tf) were conjugated to the thermosensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (poly(NIPAAm-co-PAAc)) nanogel to prepare a dual-targeting drug carrier. The obtained nanogel was characterized in terms of fluorescence spectroscopy, UV-vis spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). In order to track the dual-ligand conjugated nanogel, fluorescein isothiocyanate (FITC) was further conjugated to the nanogel. A cell internalization experiment showed that the dual-ligand conjugated nanogel exhibited obviously enhanced endocytosis by HeLa cells as compared with non-tumorous cells (COS-7 cells). The drug-loaded dual-ligand conjugated nanogel could be transported efficiently into the target tumor cells and the anti-tumor effect was enhanced significantly, suggesting that the dual-ligand conjugated nanogel has great potential as a tumor targeting drug carrier.

  17. Fluorophore-conjugated iron oxide nanoparticle labeling and analysis of engrafting human hematopoietic stem cells

    DEFF Research Database (Denmark)

    Maxwell, Dustin J; Bonde, Jesper; Hess, David A

    2008-01-01

    The use of nanometer-sized iron oxide particles combined with molecular imaging techniques enables dynamic studies of homing and trafficking of human hematopoietic stem cells (HSC). Identifying clinically applicable strategies for loading nanoparticles into primitive HSC requires strictly defined...... culture conditions to maintain viability without inducing terminal differentiation. In the current study, fluorescent molecules were covalently linked to dextran-coated iron oxide nanoparticles (Feridex) to characterize human HSC labeling to monitor the engraftment process. Conjugating fluorophores...... or in vivo. Transplantation of purified primary human cord blood lineage-depleted and CD34(+) cells into immunodeficient mice allowed detection of labeled human HSC in the recipient bones. Flow cytometry was used to precisely quantitate the cell populations that had sequestered the nanoparticles...

  18. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli, E-mail: tgl@hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhou, Lingyu [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory of Clean Energy, Dalian 116023 (China); Zhang, Jian, E-mail: jianzhang@guet.edu.cn [Department of Material Science and Engineering, Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004 (China)

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  19. Immunoglobulin and enzyme-conjugated dextran polymers enhance u-PAR staining intensity of carcinoma cells in peripheral blood smears

    DEFF Research Database (Denmark)

    Werther, K; Normark, M; Hansen, B F;

    1999-01-01

    phenotyping of disseminated carcinoma cells in bone marrow and peripheral blood smears. In the first step, the cells were incubated with antibodies against urokinase plasminogen activator receptor (u-PAR) and subsequently with secondary antibodies conjugated to peroxidase-labeled dextran polymers. A brown...... color reaction was developed with diaminobenzidine as chromogen. In the second step, the cells were incubated with alkaline phosphatase-conjugated murine monoclonal antibodies against a common cytokeratin epitope and a red color reaction was developed with new fuchsin as substrate. This method allows...

  20. Gold nanoparticle-lignan complexes inhibited MCF-7 cell proliferation in vitro: a novel conjugation for cancer therapy.

    Science.gov (United States)

    Bakar, Filiz; Caglayan, Mehmet G; Onur, Feyyaz; Nebioglu, Serpil; Palabiyik, Ismail M

    2015-01-01

    Nanoparticles, including gold nanoparticles (AuNP), have been used in imaging in cancer treatment and as therapeutic agents and drug delivery vehicles. Particularly lignans, also called phytoestrogens, have strong effects on the treatment of carcinomas due to their antiestrogenic, antiangiogenic and proapoptotic mechanism. The aim of this study is to investigate the antiproliferative effects of three lignans-AuNP conjugates, pinoresinol (PINO), lariciresinol (LARI) and secoisolariciresinol (SECO), on the MCF-7 cell lines. For this purpose, first, thiolated β-cyclodextrin (β-CD) was synthesized to achieve a surface modification of AuNP, and then the β-CD modified AuNP was characterized using the transmission electron microscopy (TEM), UV-Visible and Nuclear Magnetic Resonance (NMR) spectroscopy. Then, the selected lignans were conjugated to the β-CD-modified AuNP, and the antiproliferative effect of these conjugates was monitored. The results suggest that when compared to their non-conjugated forms, the AuNP-bound lignan conjugates prevented the proliferation of the MCF-7 cells significantly. Therefore, these AuNP-conjugated derivatives can be new candidate agents for breast cancer therapy.

  1. Intratumoral delivery of CpG-conjugated anti-MUC1 antibody enhances NK cell anti-tumor activity.

    Science.gov (United States)

    Schettini, Jorge; Kidiyoor, Amritha; Besmer, Dahlia M; Tinder, Teresa L; Roy, Lopamudra Das; Lustgarten, Joseph; Gendler, Sandra J; Mukherjee, Pinku

    2012-11-01

    Monoclonal antibodies (mAbs) against tumor-associated antigens are useful anticancer agents. Antibody-dependent cellular cytotoxicity (ADCC) is one of the major mechanisms responsible for initiating natural killer cell (NK)-mediated killing of tumors. However, the regulation of ADCC via NK cells is poorly understood. We have investigated the cytolytic activity of NK cells against pancreatic cancer cells that were coated with an antibody directed against the human tumor antigen, Mucin-1 designated HMFG-2, either alone or conjugated to CpG oligodeoxynucleotide (CpG ODN). Conjugated antibodies were tested for their ability to elicit ADCC in vitro and in vivo against pancreatic cancer cells. NK cells cultured in the presence of immobilized CpG ODN, HMFG-2 Ab, or CpG ODN-conjugated HMFG-2 Ab were able to up-regulate perforin similarly. Interestingly, a significant higher ADCC was observed when CpG ODN-conjugated HMFG-2-coated tumor cells were co-cultured with NK cells compared to unconjugated HMFG-2 Ab or CpG ODN alone. Moreover, MyD88-deficient NK cells can perform ADCC in vitro. Furthermore, intratumoral injections of CpG ODN-conjugated HMFG-2 induced a significant reduction in tumor burden in vivo in an established model of pancreatic tumor in nude mice compared to CpG ODN or the HMFG-2 alone. Depletion of macrophages or NK cells before treatment confirmed that both cells were required for the anti-tumor response in vivo. Results also suggest that CpG ODN and HMFG-2 Ab could be sensed by NK cells on the mAb-coated tumor cells triggering enhanced ADCC in vitro and in vivo.

  2. Aptamer-miRNA-212 Conjugate Sensitizes NSCLC Cells to TRAIL

    Directory of Open Access Journals (Sweden)

    Margherita Iaboni

    2016-01-01

    Full Text Available TNF-related apoptosis-inducing ligand (TRAIL is a promising antitumor agent for its remarkable ability to selectively induce apoptosis in cancer cells, without affecting the viability of healthy bystander cells. The TRAIL tumor suppressor pathway is deregulated in many human malignancies including lung cancer. In human non-small cell lung cancer (NSCLC cells, sensitization to TRAIL therapy can be restored by increasing the expression levels of the tumor suppressor microRNA-212 (miR-212 leading to inhibition of the anti-apoptotic protein PED/PEA-15 implicated in treatment resistance. In this study, we exploited a previously described RNA aptamer inhibitor of the tyrosine kinase receptor Axl (GL21.T expressed on lung cancer cells, as a means to deliver miR-212 into human NSCLC cells expressing Axl. We demonstrate efficient delivery of miR-212 following conjugation of the miR to GL21.T (GL21.T-miR212 chimera. We show that the chimera downregulates PED and restores TRAIL-mediate cytotoxicity in cancer cells. Importantly, treatment of Axl+ lung cancer cells with the chimera resulted in (i an increase in caspase activation and (ii a reduction of cell viability in combination with TRAIL therapy. In conclusion, we demonstrate that the GL21.T-miR212 chimera can be employed as an adjuvant to TRAIL therapy for the treatment of lung cancer.

  3. Quantitation of antibody-secreting cells in the blood after vaccination with Haemophilus influenzae type b conjugate vaccine

    DEFF Research Database (Denmark)

    Barington, T; Heilmann, C; Andersen, V

    1990-01-01

    The human B-lymphocyte response to protein-conjugated polysaccharide antigens has not previously been studied at the cellular level. In order to do so, we developed and evaluated haemolytic plaque-forming cell assays detecting Haemophilus influenzae type b (Hib) capsular polysaccharide-specific a......The human B-lymphocyte response to protein-conjugated polysaccharide antigens has not previously been studied at the cellular level. In order to do so, we developed and evaluated haemolytic plaque-forming cell assays detecting Haemophilus influenzae type b (Hib) capsular polysaccharide...... capsular polysaccharides from Hib and pneumococci. The predominance of IgA AbSC in response to both conjugate and pure polysaccharide vaccines is probably due to reactivation of the same clones of IgA-committed memory B cells originally primed at the mucosa by natural exposure to the polysaccharide...

  4. Realization of Large Area Flexible Fullerene - Conjugated Polymer Photocells : A Route to Plastic Solar Cells

    NARCIS (Netherlands)

    Brabec, C.J.; Padinger, F.; Hummelen, J.C.; Janssen, R.A.J.; Sariciftci, N.S.

    1999-01-01

    Bulk donor - acceptor heterojunctions between conjugated polymers and fullerenes have been utilized for photovoltaic devices with quantum efficiencies of around 1%. These devices are based on the photoinduced, ultrafast electron transfer between non degenerate ground state conjugated polymers and fu

  5. Biological evaluation of a novel Herceptin-platinum (II) conjugate for efficient and cancer cell specific delivery.

    Science.gov (United States)

    Huang, Rong; Sun, Yu; Zhang, Xiang-yang; Sun, Bai-wang; Wang, Qiu-cui; Zhu, Jin

    2015-07-01

    Platinum-based drugs have been widely used for the treatment of malignant tumors. However, their applications are limited by severe side effects for their lack of selectivity for cancer cells. The development of antibody drug conjugates (ADCs) have provided a platform to reduce drug toxicity and improve drug efficacy. Here we describe a nover conjugate comprising of Herceptin (an anti-HER2 antibody) and platinum drug via a cathepsin B cleavable dipetide for enhancing drug accumulation and HER2-positive cancer cell specific delivery. This conjugate is believed to be cleaved by cathepsin B, leading to a 1,6-elimination reaction and activation of drug release. Herceptin-Pt(II) is evaluated to have approximately loaded with 6.4 moles platinum drugs per mole of antibody. We demonstrate that Herceptin-Pt(II) retain high and selective binding affinity for HER2 protein and HER2-positive SK-BR-3 cancer cells. The in vitro cytotoxicity tests indicate that Herceptin-Pt(II) exhibits much higher cytotoxicity than oxaliplatin against SK-BR-3 cells. More importantly, Herceptin-Pt(II) shows no obvious inhibition against the growth of both MCF-7 and MDA-MB-231 cells, which express lower levels of HER2. Furthermore, compared with free oxaliplatin, Herceptin significantly improved the cellular uptake of platinum drugs in SK-BR-3 cells. In summary, Herceptin-platinum (II) conjugate is a remarkable and potent platform for efficient and cancer cell specific delivery.

  6. Conjugated oligoelectrolyte represses hydrogen oxidation by Geobacter sulfurreducens in microbial electrolysis cells

    KAUST Repository

    Liu, Jia

    2015-12-01

    © 2015 Elsevier B.V. A conjugated oligoelectrolyte (COE), which spontaneously aligns within cell membranes, was shown to completely inhibit H2 uptake by Geobacter sulfurreducens in microbial electrolysis cells. Coulombic efficiencies that were 490±95%, due to H2 recycling between the cathode and microorganisms on the anode, were reduced to 86±2% with COE addition. The use of the COE resulted in a 67-fold increase in H2 gas recovery, and a 4.4-fold increase in acetate removal. Current generation, H2 recovery and COD removals by Geobacter metallireducens, which cannot use H2, were unaffected by COE addition. These results show that this COE is an effective H2 uptake inhibitor, and that it can enable improved and sustained H2 gas recovery in this bioelectrochemical system.

  7. Conjugated oligoelectrolyte represses hydrogen oxidation by Geobacter sulfurreducens in microbial electrolysis cells.

    Science.gov (United States)

    Liu, Jia; Hou, Huijie; Chen, Xiaofen; Bazan, Guillermo C; Kashima, Hiroyuki; Logan, Bruce E

    2015-12-01

    A conjugated oligoelectrolyte (COE), which spontaneously aligns within cell membranes, was shown to completely inhibit H2 uptake by Geobacter sulfurreducens in microbial electrolysis cells. Coulombic efficiencies that were 490±95%, due to H2 recycling between the cathode and microorganisms on the anode, were reduced to 86±2% with COE addition. The use of the COE resulted in a 67-fold increase in H2 gas recovery, and a 4.4-fold increase in acetate removal. Current generation, H2 recovery and COD removals by Geobacter metallireducens, which cannot use H2, were unaffected by COE addition. These results show that this COE is an effective H2 uptake inhibitor, and that it can enable improved and sustained H2 gas recovery in this bioelectrochemical system.

  8. Anticancer Effects of Sinulariolide-Conjugated Hyaluronan Nanoparticles on Lung Adenocarcinoma Cells

    Directory of Open Access Journals (Sweden)

    Kuan Yin Hsiao

    2016-03-01

    Full Text Available Lung cancer is one of the most clinically challenging malignant diseases worldwide. Sinulariolide (SNL, extracted from the farmed coral species Sinularia flexibilis, has been used for suppressing malignant cells. For developing anticancer therapeutic agents, we aimed to find an alternative for non-small cell lung cancer treatment by using SNL as the target drug. We investigated the SNL bioactivity on A549 lung cancer cells by conjugating SNL with hyaluronan nanoparticles to form HA/SNL aggregates by using a high-voltage electrostatic field system. SNL was toxic on A549 cells with an IC50 of 75 µg/mL. The anticancer effects of HA/SNL aggregates were assessed through cell viability assay, apoptosis assays, cell cycle analyses, and western blotting. The size of HA/SNL aggregates was approximately 33–77 nm in diameter with a thin continuous layer after aggregating numerous HA nanoparticles. Flow cytometric analysis revealed that the HA/SNL aggregate-induced apoptosis was more effective at a lower SNL dose of 25 µg/mL than pure SNL. Western blotting indicated that caspases-3, -8, and -9 and Bcl-xL and Bax played crucial roles in the apoptotic signal transduction pathway. In summary, HA/SNL aggregates exerted stronger anticancer effects on A549 cells than did pure SNL via mitochondria-related pathways.

  9. Evaluation of the effects of chemically different linkers on hepatic accumulations, cell tropism and gene silencing ability of cholesterol-conjugated antisense oligonucleotides.

    Science.gov (United States)

    Wada, Shunsuke; Yasuhara, Hidenori; Wada, Fumito; Sawamura, Motoki; Waki, Reiko; Yamamoto, Tsuyoshi; Harada-Shiba, Mariko; Obika, Satoshi

    2016-03-28

    Cholesterol conjugation of oligonucleotides is an attractive way to deliver the oligonucleotides specifically to the liver. However cholesterol-conjugated antisense oligonucleotides (ASOs) mainly accumulate in non-parenchymal cells (NPCs) such as Kupffer cells. In this study, to increase the hepatic accumulation of cholesterol-conjugated ASOs, we prepared a variety of linkers for cholesterol conjugation to anti-Pcsk9 ASOs and examined their effects on pharmacological parameters. Hepatic accumulation of ASO was dramatically increased with cholesterol conjugation. The increase in hepatic accumulation depended largely on the linker chemistry of each cholesterol-conjugated ASO. In addition to hepatic accumulation, the cell tropism of each cholesterol-conjugated ASO tended to depend on their linker. Although a linker bearing a disulfide bond accumulated mainly in NPCs, hexamethylene succinimide linker accumulated mainly in hepatocytes. To estimate the benefits of releasing ASO from the conjugated cholesterol in hepatocyte, we designed another linker based on hexamethylene succinimide, which has a phosphodiester bond between the linker and the ASO. The cholesterol-conjugated ASO bearing such a phosphodiester bond showed a significantly improved Pcsk9 mRNA inhibitory effect compared to its counterpart, cholesterol-conjugated ASO with a phosphorothioate bond, while the hepatic accumulation of both cholesterol-conjugated ASOs was comparable, indicating the effectiveness of removing the conjugated cholesterol for ASO activity. In toxicity analysis, some of the linkers induced lethal toxicities when they were injected at high concentrations (>600μM). These toxicities were attributed to decreased platelet levels in the blood, suggesting an interaction between cholesterol-conjugated ASO and platelets. Our findings may provide a guideline for the design of molecule-conjugated ASOs. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Antigen-engaged B cells undergo chemotaxis toward the T zone and form motile conjugates with helper T cells.

    Directory of Open Access Journals (Sweden)

    Takaharu Okada

    2005-06-01

    Full Text Available Interactions between B and T cells are essential for most antibody responses, but the dynamics of these interactions are poorly understood. By two-photon microscopy of intact lymph nodes, we show that upon exposure to antigen, B cells migrate with directional preference toward the B-zone-T-zone boundary in a CCR7-dependent manner, through a region that exhibits a CCR7-ligand gradient. Initially the B cells show reduced motility, but after 1 d, motility is increased to approximately 9 microm/min. Antigen-engaged B cells pair with antigen-specific helper T cells for 10 to more than 60 min, whereas non-antigen-specific interactions last less than 10 min. B cell-T cell conjugates are highly dynamic and migrate extensively, being led by B cells. B cells occasionally contact more than one T cell, whereas T cells are strictly monogamous in their interactions. These findings provide evidence of lymphocyte chemotaxis in vivo, and they begin to define the spatiotemporal cellular dynamics associated with T cell-dependent antibody responses.

  11. A new strategy for specific imaging of neural cells based on peptide-conjugated gold nanoclusters

    Directory of Open Access Journals (Sweden)

    Zhang E

    2015-03-01

    Full Text Available Enqi Zhang, Ailing Fu School of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China Abstract: Despite the significant progress in molecular imaging technologies that has been made in recent years, the specific detection of neural cells still remains challenging. Here, we suggest the use of gold nanoclusters (AuNCs modified with a brain-targeting peptide as a potential imaging candidate for detecting neural cells in vitro and in mice. AuNCs of less than 10 nm (dynamic light scattering analysis were first prepared using the “green” synthetic approach, and then a targeting peptide, rabies virus glycoprotein derived peptide (RDP, was conjugated to the AuNCs for improving the efficiency and specificity of neural cell penetration. The conjugate’s mechanism of cellular attachment and entry into neural cells was suggested to be receptor-mediated endocytosis through clathrin-coated pits. Also, noninvasive imaging analysis and animal studies indicated that the RDP-modified nanoclusters could concentrate in the brain and locate in neural cells. This study suggests the feasibility of using targeting peptide-modified nanoclusters for noninvasive imaging brain cells in vivo. Keywords: RDP, targeted delivery, bioimaging, brain 

  12. Enhancing microparticle internalization by nonphagocytic cells through the use of noncovalently conjugated polyethyleneimine.

    Science.gov (United States)

    Patiño, Tania; Nogués, Carme; Ibáñez, Elena; Barrios, Leonardo

    2012-01-01

    Development of micro- and nanotechnology for the study of living cells, especially in the field of drug delivery, has gained interest in recent years. Although several studies have reported successful results in the internalization of micro- and nanoparticles in phagocytic cells, when nonphagocytic cells are used, the low internalization efficiency represents a limitation that needs to be overcome. It has been reported that covalent surface modification of micro- and nanoparticles increases their internalization rate. However, this surface modification represents an obstacle for their use as drug-delivery carriers. For this reason, the aim of the present study was to increase the capability for microparticle internalization of HeLa cells through the use of noncovalently bound transfection reagents: polyethyleneimine (PEI) Lipofectamine™ 2000 and FuGENE 6(®). Both confocal microscopy and flow cytometry techniques allowed us to precisely quantify the efficiency of microparticle internalization by HeLa cells, yielding similar results. In addition, intracellular location of microparticles was analyzed through transmission electron microscopy and confocal microscopy procedures. Our results showed that free PEI at a concentration of 0.05 mM significantly increased microparticle uptake by cells, with a low cytotoxic effect. As determined by transmission electron and confocal microscopy analyses, microparticles were engulfed by plasma-membrane projections during internalization, and 24 hours later they were trapped in a lysosomal compartment. These results show the potential use of noncovalently conjugated PEI in microparticle internalization assays.

  13. Chlorin e6 Conjugated Interleukin-6 Receptor Aptamers Selectively Kill Target Cells Upon Irradiation

    Directory of Open Access Journals (Sweden)

    Sven Kruspe

    2014-01-01

    Full Text Available Photodynamic therapy (PDT uses the therapeutic properties of light in combination with certain chemicals, called photosensitizers, to successfully treat brain, breast, prostate, and skin cancers. To improve PDT, current research focuses on the development of photosensitizers to specifically target cancer cells. In the past few years, aptamers have been developed to directly deliver cargo molecules into target cells. We conjugated the photosensitizer chlorin e6 (ce6 with a human interleukin-6 receptor (IL-6R binding RNA aptamer, AIR-3A yielding AIR-3A-ce6 for application in high efficient PDT. AIR-3A-ce6 was rapidly and specifically internalized by IL-6R presenting (IL-6R+ cells. Upon light irradiation, targeted cells were selectively killed, while free ce6 did not show any toxic effect. Cells lacking the IL-6R were also not affected by AIR-3A-ce6. With this approach, we improved the target specificity of ce6-mediated PDT. In the future, other tumor-specific aptamers might be used to selectively localize photosensitizers into cells of interest and improve the efficacy and specificity of PDT in cancer and other diseases.

  14. Milk fat conjugated linoleic acid (CLA) inhibits growth of human mammary MCF-7 cancer cells.

    Science.gov (United States)

    O'Shea, M; Devery, R; Lawless, F; Murphy, J; Stanton, C

    The relationship between growth and the antioxidant enzyme defence system in human MCF-7 (breast) cancer cells treated with bovine milk fat enriched with conjugated linoleic acid (CLA) was studied. Milk enriched in CLA was obtained from cows on pasture supplemented with full fat rapeseeds and full fat soyabeans (1). Cell number decreased up to 90% (p milk fat yielding CLA concentrations between 16.9 and 22.6 ppm. Growth suppression and prooxidant effects of milk fat CLA were independent of the variable composition of the milk fat samples, suggesting that CLA was the active ingredient in milk fat responsible for the cytotoxic effect. Mixtures containing isomers of CLA (c9, t11-, t10, c12-, c11, t13- and minor amounts of other isomers) and linoleic acid (LA) at similar concentrations to the milk fat samples were as effective at inhibiting growth and stimulating peroxidation of MCF-7 cells as the milk fatty acids. Incubation of the cells with the c9, t11 CLA isomer (20 ppm) or the mixture of CLA isomers (20 ppm) for 8 days resulted in a 60% decrease (p milk fat than the c9, t11 synthetic CLA isomer. Superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities were induced in MCF-7 cells exposed to milk fat (containing 16.9-22.6 ppm CLA) over 8 days. The data indicate that milk fat triglyceride-bound CLA, consisting primarily of the c9, t11 isomer, was cytotoxic towards MCF-7 cells.

  15. Synthesis of novel conjugates of a saccharide, amino acids, nucleobase and the evaluation of their cell compatibility

    Directory of Open Access Journals (Sweden)

    Dan Yuan

    2014-10-01

    Full Text Available This article reports the synthesis of a novel type of conjugate of three fundamental biological build blocks (i.e., saccharide, amino acids, and nucleobase and their cell compatibility. The facile synthesis starts with the synthesis of nucleobase and saccharide derivatives, then uses solid-phase peptide synthesis (SPPS to build the peptide segment (Phe-Arg-Gly-Asp or naphthAla-Phe-Arg-Gly-Asp with fully protected groups, and later, an amidation reaction in liquid phase connects these three parts together. The overall yield of these multiple step synthesis is about 34%. Besides exhibiting excellent solubility, these conjugates of saccharide–amino acids–nucleobase (SAN, like the previously reported conjugates of nucleobase–amino acids–saccharide (NAS and nucleobase–saccharide–amino acids (NSA, are mammalian cell compatible.

  16. π-Conjugated Donor-Acceptor Systems as Metal-Free Sensitizers for Dye-Sensitized Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Zakeeruddin S. M.

    2013-03-01

    Full Text Available High extinction coefficients and easily tunable spectral properties of π- conjugated donor-acceptor dyes are of superior advantage for the design of new metalfree organic sensitizers for applications in dye-sensitized solar cells. Ultrafast transient absorption spectroscopy on the femtosecond and nanosecond time scales provided deep insights into the dependence of charge carrier dynamics in fully organic dye/TiO2 systems on i the donor-acceptor distance, ii the π-conjugation length, and iii the coupling to TiO2 by different anchoring groups. Importantly, the observed differences in charge transfer dynamics justify the variations of photovoltaic performances of the dyes as applied in solar cell devices. This leads to the conclusion that the photoconversion efficiencies strongly depend on a delicate interplay between the dyes’ building blocks, i.e. the donor, the π-conjugated spacer and the anchor/acceptor moieties, and may easily be tuned by molecular design.

  17. The Curious Case of Fluorination of Conjugated Polymers for Solar Cells.

    Science.gov (United States)

    Zhang, Qianqian; Kelly, Mary Allison; Bauer, Nicole; You, Wei

    2017-09-19

    Organic solar cells (OSCs) have been a rising star in the field of renewable energy since the introduction of the bulk heterojunction (BHJ) in 1992. Recent advances have pushed the efficiencies of OSCs to over 13%, an impressive accomplishment via collaborative efforts in rational materials design and synthesis, careful device engineering, and fundamental understanding of device physics. Throughout these endeavors, several design principles for the conjugated donor polymers used in such solar cells have emerged, including optimizing the conjugated backbone with judicious selection of building blocks, side-chain engineering, and substituents. Among all of the substituents, fluorine is probably the most popular one; improved device characteristics with fluorination have frequently been reported for a wide range of conjugated polymers, in particular, donor-acceptor (D-A)-type polymers. Herein we examine the effect of fluorination on the device performance of solar cells as a function of the position of fluorination (on the acceptor unit or on the donor unit), aiming to outline a clear understanding of the benefits of this curious substituent. As fluorination of the acceptor unit is the most adopted strategy for D-A polymers, we first discuss the effect of fluorination of the acceptor units, highlighting the five most widely utilized acceptor units. While improved device efficiency has been widely observed with fluorinated acceptor units, the underlying reasons vary from case to case and highly depend on the chemical structure of the polymer. Second, the effect of fluorination of the donor unit is addressed. Here we focus on four donor units that have been most studied with fluorination. While device-performance-enhancing effects by fluorination of the donor units have also been observed, it is less clear that fluorine will always benefit the efficiency of the OSC, as there are several cases where the efficiency drops, in particular with "over-fluorination", i.e., when

  18. Sensitivity of gastric adenocarcinoma and normal cell lines against combined or conjugated antimetabolites.

    Science.gov (United States)

    Weinreich, Jürgen; Struller, Florian; Küper, Markus; Hack, Anita; Königsrainer, Alfred; Schott, Timm C

    2013-04-01

    The in-vitro growth inhibition of cancer and normal cell lines caused by mixed or covalently linked antimetabolites should clarify whether the conjugation of antimetabolites influences cell sensitivity and growth inhibition in a manner that differs from an equimolar mixture of the same antimetabolites or not. Growth inhibition of the human gastric adenocarcinoma cell lines 23132/87 and MKN-45 in comparison with normal gastric intestinal CCL-241 and the dermal fibroblast cell line NHDF was evaluated using CASY technology. The cell lines were incubated with an equimolar mixture of 5-fluoro-2'-deoxyuridine (5FdU)+3'-C-ethynylcytidine (ECyd) or the covalently linked duplex drug 5FdU(5'→5')ECyd. The drug and metabolites of the assays and medium were determined semiquantitatively using high-performance liquid chromatography. The sensitivity of cancer and nonmalignant cell lines was clearly different against the duplex drug. A measure of 0.65 µmol/l 5FdU(5'→5')ECyd, for example, reduced the growth of MKN-45 or 23132/87 gastric cancer cells from 100% on day 0 to about 50 or 20% on day 10, respectively. However, under the same conditions, the growth of the nonmalignant NHDF and CCL-241 cell lines was not markedly inhibited. The cytostatic activity of the duplex drug is based on the active metabolites in and outside the cell formed by the degradation of 5FdU(5'→5')ECyd. The sensitivity of cell lines against the duplex drug depended on its ability to metabolize the duplex drug. 5FdU(5'→5')ECyd should be more advantageous for specific and efficient polychemotherapy of gastric cancer than the corresponding equimolar mixture of 5FdU+ECyd or a standard combination regime of single drugs.

  19. A water soluble vitamin B12-ReI fluorescent conjugate for cell uptake screens: use in the confirmation of cubilin in the lung cancer line A549.

    Science.gov (United States)

    Vortherms, Anthony R; Kahkoska, Anna R; Rabideau, Amy E; Zubieta, Jon; Andersen, Louise Lund; Madsen, Mette; Doyle, Robert P

    2011-09-21

    A water soluble vitamin B(12)-rhenium conjugate was synthesized and used in concert with intrinsic factor to screen for cubilin receptor-mediated uptake in lung cancer cells. Internalization of the conjugate demonstrated that it could be used to rapidly screen for the cubilin receptor in living cells, subsequently confirmed with Western blotting and RT-PCR.

  20. Enhancement of intracellular concentration and biological activity of PNA after conjugation with a cell-penetrating synthetic model peptide.

    Science.gov (United States)

    Oehlke, Johannes; Wallukat, Gerd; Wolf, Yvonne; Ehrlich, Angelika; Wiesner, Burkhard; Berger, Hartmut; Bienert, Michael

    2004-07-01

    In order to evaluate the ability of the cell-penetrating alpha-helical amphipathic model peptide KLALKLALKALKAALKLA-NH(2) (MAP) to deliver peptide nucleic acids (PNAs) into mammalian cells, MAP was covalently linked to the 12-mer PNA 5'-GGAGCAGGAAAG-3' directed against the mRNA of the nociceptin/orphanin FQ receptor. The cellular uptake of both the naked PNA and its MAP-conjugate was studied by means of capillary electrophoresis combined with laser-induced fluorescence detection, confocal laser scanning microscopy and fluorescence-activated cell sorting. Incubation with the fluorescein-labelled PNA-peptide conjugate led to three- and eightfold higher intracellular concentrations in neonatal rat cardiomyocytes and CHO cells, respectively, than found after exposure of the cells to the naked PNA. Correspondingly, pretreatment of spontaneously-beating neonatal rat cardiomyocytes with the PNA-peptide conjugate and the naked PNA slowed down the positive chronotropic effect elicited by the neuropeptide nociceptin by 10- and twofold, respectively. The main reasons for the higher bioavailability of the PNA-peptide conjugate were found to be a more rapid cellular uptake in combination with a lowered re-export and resistance against influences of serum.

  1. Peptide Conjugation to a Polymer Coating via Native Chemical Ligation of Azlactones for Cell Culture.

    Science.gov (United States)

    Schmitt, Samantha K; Trebatoski, David J; Krutty, John D; Xie, Angela W; Rollins, Benjamin; Murphy, William L; Gopalan, Padma

    2016-03-14

    Conjugation of biomolecules for stable presentation is an essential step toward reliable chemically defined platforms for cell culture studies. In this work, we describe the formation of a stable and site-specific amide bond via the coupling of a cysteine terminated peptide at low concentration to an azlactone containing copolymer coating. A copolymer of polyethylene glycol methyl ether methacrylate-ran-vinyl azlactone-ran-glycidyl methacrylate P(PEGMEMA-r-VDM-r-GMA) was used to form a thin coating (20-30 nm) on silicon and polycarbonate substrates. The formation and stability of coating-peptide bonds for peptides containing free thiols and amines were quantified by X-ray photoelectron spectroscopy (XPS) after exposure to cell culture conditions. Peptides containing a thiol as the only nucleophile coupled via a thioester bond; however, the bond was labile under cell culture conditions and almost all the bound peptides were displaced from the surface over a period of 2 days. Coupling with N-terminal primary amine peptides resulted in the formation of an amide bond with low efficiency (chemical ligation. Through a combination of XPS and cell culture studies, we show that the cysteine terminated peptides undergo a native chemical ligation process at low peptide concentration in aqueous media, short reaction time, and at room temperature resulting in the stable presentation of peptides beyond 2 weeks for cell culture studies.

  2. Peptide-Conjugated Quantum Dots Act as the Target Marker for Human Pancreatic Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Shuang-ling Li

    2016-03-01

    Full Text Available Background/Aims: In the present study, we describe a novel and straightforward approach to produce a cyclic- arginine-glycine-aspartic (RGD-peptide-conjugated quantum dot (QD probe as an ideal target tumor biomarker. Due to its specific structure, the probe can be used for targeted imaging of pancreatic carcinoma cells. Methods: Pancreatic carcinoma cells were routinely cultured and marked with QD-RGD probe. The QD-RGD probe on the fluorescence-labeled cancer cell was observed by fluorescence microscopy and laser confocal microscopy. Cancer cell viability was detected by MTT assay after culturing with QD-RGD probe. Results: Fluorescence microscopy and laser confocal microscopy displayed that 10nmol/L QD-RGD probe was able to effectively mark pancreatic carcinoma cells. In comparison with organic dyes and fluorescent proteins, the quantum dot-RGD probe had unique optical and electronic properties. Conclusion: QD-RGD probe has a low cytotoxicity with an excellent optical property and biocompatibility. These findings support further evaluation of QD-RGD probes for the early detection of pancreatic cancer.

  3. Carbon nanotubes-liposomes conjugate as a platform for drug delivery into cells.

    Science.gov (United States)

    Karchemski, Faina; Zucker, Daniel; Barenholz, Yechezkel; Regev, Oren

    2012-06-10

    Carbon nanotubes (CNT) are widely explored as carriers for drug delivery due to their facile transport through cellular membranes. However, the amount of loaded drug on a CNT is rather small. Liposomes, on the other hand, are employed as a carrier of a large amount of drug. The aim of this research is to develop a new drug delivery system, in which drug-loaded liposomes are covalently attached to CNT to form a CNT-liposomes conjugate (CLC). The advantage of this novel approach is the large amount of drug that can be delivered into cells by the CLC system, thus preventing potential adverse systemic effects of CNT when administered at high doses. This system is expected to provide versatile and controlled means for enhanced delivery of one or more agents stably associated with the liposomes.

  4. Planar conjugated polymers containing 9,10-disubstituted phenanthrene units for efficient polymer solar cells.

    Science.gov (United States)

    Li, Guangwu; Kang, Chong; Li, Cuihong; Lu, Zhen; Zhang, Jicheng; Gong, Xue; Zhao, Guangyao; Dong, Huanli; Hu, Wenping; Bo, Zhishan

    2014-06-01

    Four novel conjugated polymers (P1-4) with 9,10-disubstituted phenanthrene (PhA) as the donor unit and 5,6-bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low-lying HOMO energy levels (below -5.3 eV), and high hole mobilities (in the range of 3.6 × 10(-3) to 0.02 cm(2) V(-1) s(-1) ). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1-4:PC71 BM blends as the active layer and an alcohol-soluble fullerene derivative (FN-C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10-disubstituted PhA are potential donor materials for high-efficiency BHJ PSCs.

  5. Reversible photoswitching conjugated polymer nanoparticles for cell and ex vivo tumor imaging

    Science.gov (United States)

    Feng, Guangxue; Ding, Dan; Li, Kai; Liu, Jie; Liu, Bin

    2014-03-01

    Fluorescent photoswitchable conjugated polymer nanoparticles (PCPNPs) bearing poly(9,9-dihexylfluorene-alt-2,1,3-benzoxadiazole) (PFBD) as the fluorescent host polymer and the photochromic diarylethene as toggle are synthesized via a modified nano-precipitation method using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG-NH2) as the encapsulation matrix. The PCPNPs are spherical in shape with diameters around 34 nm. The fluorescence switching processes upon UV and white light illumination are successfully demonstrated with high contrast up to 90-fold, recovery efficiency of 95%, and excellent repeatability in solution. The cationic PCPNPs can be easily internalized into cancer cells, and accumulate in tumor tissues, where the fluorescence photoswitching processes can be used to self-validate the imaging results.

  6. Steroid Probes Conjugated with Protein-Protected Gold Nanocluster: Specific and Rapid Fluorescence Imaging of Steroid Receptors in Target Cells.

    Science.gov (United States)

    Tsai, Chi-Yan; Li, Chun-Wei; Li, Jie-Ren; Jang, Bo-Han; Chen, Shu-Hui

    2016-07-01

    Steroid ligands can easily diffuse through the cell membrane and this property makes it feasible to be used for in-situ staining of the nuclear receptors. However, nonspecific binding of the internalized ligand probe with the cellular components has caused serious interferences for the detection of receptor-expressing cells. We report a novel gold nanocluster (AuNC)-conjugated estrogen probe that can eliminate nonspecific internalization and accelerate nuclear localization to achieve selective and rapid detection of estrogen receptors (ERs) in live cells. The AuNC, protected by bovine serum albumin (BSA), BSA-AuNCs, was prepared by the synthesis and confirmed to be 1.9 nm in core size and 18 nm in diameter. Ethinyl estradiol was used as the precursor of 17β-estradial (E2) to conjugate with BSA-protected AuNCs via polyethylene glycol linker (E2-PEG/BSA-AuNCs) or to conjugate with Cy3 dyes (E2-Cy3). The conjugated probe was determined to contain five E2 molecules per BSA-AuNC by mass spectrometry and exhibit an emission maximum of around 640 nm, which was not altered by E2 conjugation indicating that the structural integrity of BSA-AuNCs was conserved. E2-PEG/BSA-AuNCs probes were quickly internalized by MCF-7 (ER+) cells and localized to the nuclei in 2 h. Such internalization was sensitive to competition by free E2 and was rarely detected in the controls using either non-conjugated BSA-AuNCs in MCF-7 (ER+) cells or E2-PEG/BSA-AuNCs in MDA-MB-231 (ER-) cells. In contrast to the high specificity of E2-PEG/BSA-AuNCs probe, the uptake of E2-Cy3 probe could not differentiate between MCF-7(ER+) and MDA-MB-231(ER-) cells during the early phases of the treatment. Moreover, nuclear targeting by E2-Cy3 was three times slower than that by the E2-PEG/BSA-AuNC probe. Such accelerated nuclei targeting was consistent with the enhanced cell viability by conjugating E2 with BSA-AuNC. In conclusion, the E2-PEG/BSA-AuNC probes are promising candidates that can be used for the

  7. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    Science.gov (United States)

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm; Iversen, Frank; Liu, Zhuo; Thomsen, Karen; Pedersen, Michael; Skrydstrup, Troels; Nielsen, Niels Chr.; Ploug, Michael; Kjems, Jørgen

    2013-08-01

    Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific

  8. Asymmetric Diketopyrrolopyrrole Conjugated Polymers for Field-Effect Transistors and Polymer Solar Cells Processed from a Nonchlorinated Solvent.

    Science.gov (United States)

    Ji, Yunjing; Xiao, Chengyi; Wang, Qiang; Zhang, Jianqi; Li, Cheng; Wu, Yonggang; Wei, Zhixiang; Zhan, Xiaowei; Hu, Wenping; Wang, Zhaohui; Janssen, René A J; Li, Weiwei

    2016-02-01

    Newly designed asymmetric diketopyrrolopyrrole conjugated polymers with two different aromatic substituents possess a hole mobility of 12.5 cm(2) V(-1) s(-1) in field-effect transistors and a power conversion efficiency of 6.5% in polymer solar cells, when solution processed from a nonchlorinated toluene/diphenyl ether mixed solvent.

  9. Non-covalent conjugates of single-walled carbon nanotubes and folic acid for interaction with cells overexpressing folate receptors

    DEFF Research Database (Denmark)

    Castillo, John J.; Rindzevicius, Tomas; Novoa, Leidy V.

    2013-01-01

    We here present amethod to form a noncovalent conjugate of single-walled carbon nanotubes and folic acid aimed to interact with cells over-expressing folate receptors. The bonding was obtained without covalent chemical functionalization using a simple, rapid “one pot” synthesis method. The zeta p...

  10. Immunoglobulin and enzyme-conjugated dextran polymers enhance u-PAR staining intensity of carcinoma cells in peripheral blood smears

    DEFF Research Database (Denmark)

    Werther, K; Normark, M; Hansen, B F;

    1999-01-01

    color reaction was developed with diaminobenzidine as chromogen. In the second step, the cells were incubated with alkaline phosphatase-conjugated murine monoclonal antibodies against a common cytokeratin epitope and a red color reaction was developed with new fuchsin as substrate. This method allows...

  11. Parallel Synthesis of Cell-Penetrating Peptide Conjugates of PMO Toward Exon Skipping Enhancement in Duchenne Muscular Dystrophy

    NARCIS (Netherlands)

    O'Donovan, Liz; Okamoto, Itaru; Arzumanov, Andrey A.; Williams, Donna L.; Deuss, Peter; Gait, Michael J.

    2015-01-01

    We describe two new methods of parallel chemical synthesis of libraries of peptide conjugates of phosphorodiamidate morpholino oligonucleotide (PMO) cargoes on a scale suitable for cell screening prior to in vivo analysis for therapeutic development. The methods represent an extension of the

  12. New conjugated molecular scaffolds based on [2,2]paracyclophane as electron acceptors for organic photovoltaic cells.

    Science.gov (United States)

    Yang, Yang; Zhang, Guanxin; Yu, Chenmin; He, Chang; Wang, Jianguo; Chen, Xin; Yao, Jingjing; Liu, Zitong; Zhang, Deqing

    2014-09-07

    Two conjugated molecules with a [2,2]paracyclophane core were designed as non-fullerene electron acceptors for photovoltaic cells. Using as the donor, a high power conversion efficiency (2.69%) is achieved for the blending thin film of with , which is relatively high for solution-processed OPVs based on small molecular non-fullerene acceptors and as the electron donor.

  13. Parallel Synthesis of Cell-Penetrating Peptide Conjugates of PMO Toward Exon Skipping Enhancement in Duchenne Muscular Dystrophy

    NARCIS (Netherlands)

    O'Donovan, Liz; Okamoto, Itaru; Arzumanov, Andrey A.; Williams, Donna L.; Deuss, Peter; Gait, Michael J.

    2015-01-01

    We describe two new methods of parallel chemical synthesis of libraries of peptide conjugates of phosphorodiamidate morpholino oligonucleotide (PMO) cargoes on a scale suitable for cell screening prior to in vivo analysis for therapeutic development. The methods represent an extension of the SELecti

  14. Unsymmetrical triphenylamine-oligothiophene hybrid conjugated systems as donor materials for high-voltage solution-processed organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ripaud, Emilie; Rousseau, Theodulf; Leriche, Philippe; Roncali, Jean [Group Linear Conjugated Systems, CNRS Moltech-Anjou, University of Angers, 2Bd Lavoisier, 49045 Angers (France)

    2011-07-15

    The synthesis of unsymmetrical triphenylamine-oligothiophene hybrid conjugated systems bearing dicyanovinyl electron acceptor end-groups is presented. When used as molecular donor materials in solution-processed bulk heteroj-unction solar cells, these compounds lead to efficient devices with very high open-circuit voltages. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Directory of Open Access Journals (Sweden)

    Grégory Jubelin

    2010-09-01

    Full Text Available The cycle inhibiting factors (Cif, produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1 and p27(kip1. Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  16. Glucose-conjugated chitosan nanoparticles for targeted drug delivery and their specific interaction with tumor cells

    Science.gov (United States)

    Li, Jing; Ma, Fang-Kui; Dang, Qi-Feng; Liang, Xing-Guo; Chen, Xi-Guang

    2014-12-01

    A novel targeted drug delivery system, glucose-conjugated chitosan nanoparticles (GCNPs), was developed for specific recognition and interaction with glucose transporters (Gluts) over-expressed by tumor cells. GC was synthesized by using succinic acid as a linker between glucosamine and chitosan (CS), and successful synthesis was confirmed by NMR and elemental analysis. GCNPs were prepared by ionic crosslinking method, and characterized in terms of morphology, size, and zeta potential. The optimally prepared nanoparticles showed spherical shapes with an average particle size of (187.9 ± 3.8) nm and a zeta potential of (- 15.43 ± 0.31) mV. The GCNPs showed negligible cytotoxicity to mouse embryo fibroblast and 4T1 cells. Doxorubicin (DOX) could be efficiently entrapped into GCNPs, with a loading capacity and encapsulation efficiency of 20.11% and 64.81%, respectively. DOX-loaded nanoparticles exhibited sustained-release behavior in phosphate buffered saline (pH 7.4). In vitro cellular uptake studies showed that the GCNPs had better endocytosis ability than CSNPs, and the antitumor activity of DOX/GCNPs was 4-5 times effectiveness in 4T1 cell killing than that of DOX/CSNPs. All the results demonstrate that nanoparticles decorated with glucose have specific interactions with cancer cells via the recognition between glucose and Gluts. Therefore, Gluts-targeted GCNPs may be promising delivery agents in cancer therapies.

  17. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Science.gov (United States)

    Jubelin, Grégory; Taieb, Frédéric; Duda, David M; Hsu, Yun; Samba-Louaka, Ascel; Nobe, Rika; Penary, Marie; Watrin, Claude; Nougayrède, Jean-Philippe; Schulman, Brenda A; Stebbins, C Erec; Oswald, Eric

    2010-09-30

    The cycle inhibiting factors (Cif), produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs) through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  18. Intracellular ZnO Nanorods Conjugated with Protoporphyrin for Local Mediated Photochemistry and Efficient Treatment of Single Cancer Cell

    Directory of Open Access Journals (Sweden)

    Larsson Per-Olof

    2010-01-01

    Full Text Available Abstract ZnO nanorods (NRs with high surface area to volume ratio and biocompatibility is used as an efficient photosensitizer carrier system and at the same time providing intrinsic white light needed to achieve cancer cell necrosis. In this letter, ZnO nanorods used for the treatment of breast cancer cell (T47D are presented. To adjust the sample for intracellular experiments, we have grown the ZnO nanorods on the tip of borosilicate glass capillaries (0.5 μm diameter by aqueous chemical growth technique. The grown ZnO nanorods were conjugated using protoporphyrin dimethyl ester (PPDME, which absorbs the light emitted by the ZnO nanorods. Mechanism of cytotoxicity appears to involve the generation of singlet oxygen inside the cell. The novel findings of cell-localized toxicity indicate a potential application of PPDME-conjugated ZnO NRs in the necrosis of breast cancer cell within few minutes.

  19. Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

    Directory of Open Access Journals (Sweden)

    J. Toušek

    2015-12-01

    Full Text Available Measurements of electrical conductivity, electron work function, carrier mobility of holes and the diffusion length of excitons were performed on samples of conjugated polymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazole based conjugated copolymer (PBDTTHD − DTBTff was studied and benchmarked against the reference polymer poly-3-hexylthiophene (P3HT. We employed, respectively, four electrode conductivity measurements, Kelvin probe work function measurements, carrier mobility using charge extraction by linearly increasing voltage (CELIV measurements and diffusion length determinaton using surface photovoltage measurements.

  20. Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Toušek, J., E-mail: jiri.tousek@mff.cuni.cz; Toušková, J.; Chomutová, R. [Charles University in Prague, Faculty of Mathematics and Physics, V Holešovičkách 2, 182 00 Prague 8 (Czech Republic); Remeš, Z.; Čermák, J. [Institute of Physics of the Academy of Sciences, Cukrovarnická 10, 162 53 Prague 6 (Czech Republic); Helgesen, M.; Carlé, J. E.; Krebs, F. C. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

    2015-12-15

    Measurements of electrical conductivity, electron work function, carrier mobility of holes and the diffusion length of excitons were performed on samples of conjugated polymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazole based conjugated copolymer (PBDT{sub THD} − DTBTff) was studied and benchmarked against the reference polymer poly-3-hexylthiophene (P3HT). We employed, respectively, four electrode conductivity measurements, Kelvin probe work function measurements, carrier mobility using charge extraction by linearly increasing voltage (CELIV) measurements and diffusion length determinaton using surface photovoltage measurements.

  1. Interleukin-13 conjugated quantum dots for identification of glioma initiating cells and their extracellular vesicles.

    Science.gov (United States)

    Madhankumar, A B; Mrowczynski, Oliver D; Patel, Suhag R; Weston, Cody L; Zacharia, Brad E; Glantz, Michael J; Siedlecki, Christopher A; Xu, Li-Chong; Connor, James R

    2017-08-01

    Cadmium selenide (CdSe) based quantum dots modified with polyethylene glycol and chemically linked to interleukin-13 (IL13) were prepared with the aim of identifying the high affinity receptor (IL13Rα2) which is expressed in glioma stem cells and exosomes secreted by these cancer stem cells. IL13 conjugated quantum dots (IL13QD) were thoroughly characterized for their physicochemical properties including particle size and surface morphology. Furthermore, the specific binding of the IL13QD to glioma cells and to glioma stem cells (GSC) was verified using a competitive binding study. The exosomes were isolated from the GSC conditioned medium and the expression of IL13Rα2 in the GSC and exosomes was verified. The binding property of IL13QD to the tumor associated exosomes was initially confirmed by transmission electron microscopy. The force of attraction between the quantum dots and U251 glioma cells and the exosomes was investigated by atomic force microscopy, which indicated a higher force of binding interaction between the IL13QD and IL13Rα2 expressing glioma cells and exosomes secreted by glioma stem cells. Flow cytometry of the IL13QD and exosomes from the culture media and cerebrospinal fluid (CSF) of patients with glioma tumors indicated a distinctly populated complex pattern different from that of non-targeted quantum dots and bovine serum albumin (BSA) conjugated quantum dots confirming specific binding potential of the IL13QD to the tumor associated exosomes. The results of this study demonstrate that IL13QD can serve as an ex vivo marker for glioma stem cells and exosomes that can inform diagnosis and prognosis of patients harboring malignant disease. Functionalized quantum dots are flexible semiconductor nanomaterials which have an immense application in biomedical research. In particular, when they are functionalized with biomolecules like proteins or antibodies, they have the specialized ability to detect the expression of receptors and antigens in

  2. Indocyanine Green Derivative Covalently Conjugated with Gold Nanorods for Multimodal Phototherapy of Fibrosarcoma Cells.

    Science.gov (United States)

    Luo, Teng; Qian, Xiaoqing; Lu, Zhiyong; Shi, Yiwen; Yao, Zhirong; Chai, Xinyu; Ren, Qiushi

    2015-04-01

    A hydrophilic indocyanine green derivative (ICG-Der-02) was covalently doped into mesoporous silica-coated gold nanorods (AuNRs/mSiO2). The self-synthesized derivative offers one carboxyl functional group on a side chain, which enables ICG-Der-02 to be covalently linked to nanomaterials and reduces the probability of leakage/desorption of the dye. The detection of infrared luminescence around 1270 nm confirmed that 102 is efficiently generated by the nanocomposite (AuNRs/mSiO2-ICG-Der-02). Furthermore, a second layer of silica was coated onto the nanocomposite, which then was conjugated with the α(v) integrin-targeting cyclic peptide (RGD-4C). The cell tests showed that the resulting nanoconjugate (AuNRs/mSiO2-ICG-Der-02/RGD-4C) was able to bind preferentially to HT-1080 human fibrosarcoma cells. Due to the synergistic effect of the produced nanoconjugates, a dual-modality photothermal and photochemical therapy was successfully achieved by 808 nm irradiation. Compared to using photothermal or photochemical therapy alone, the dual-modality photothermal/photochemical therapeutic strategy proved to be more damaging to HT-1080 cells and enhanced the effectiveness of photodestruction. Our work presents a novel approach to the multimodal treatment of fibrosarcoma and shows promise for future use in cancer theranostics.

  3. Half-sandwich ruthenium(II) biotin conjugates as biological vectors to cancer cells.

    Science.gov (United States)

    Babak, Maria V; Plażuk, Damian; Meier, Samuel M; Arabshahi, Homayon John; Reynisson, Jóhannes; Rychlik, Błażej; Błauż, Andrzej; Szulc, Katarzyna; Hanif, Muhammad; Strobl, Sebastian; Roller, Alexander; Keppler, Bernhard K; Hartinger, Christian G

    2015-03-23

    Ruthenium(II)-arene complexes with biotin-containing ligands were prepared so that a novel drug delivery system based on tumor-specific vitamin-receptor mediated endocytosis could be developed. The complexes were characterized by spectroscopic methods and their in vitro anticancer activity in cancer cell lines with various levels of major biotin receptor (COLO205, HCT116 and SW620 cells) was tested in comparison with the ligands. In all cases, coordination of ruthenium resulted in significantly enhanced cytotoxicity. The affinity of Ru(II) -biotin complexes to avidin was investigated and was lower than that of unmodified biotin. Hill coefficients in the range 2.012-2.851 suggest strong positive cooperation between the complexes and avidin. To estimate the likelihood of binding to the biotin receptor/transporter, docking studies with avidin and streptavidin were conducted. These explain, to some extent, the in vitro anticancer activity results and support the conclusion that these novel half-sandwich ruthenium(II)-biotin conjugates may act as biological vectors to cancer cells, although no clear relationship between the cellular Ru content, the cytotoxicity, and the presence of the biotin moiety was observed.

  4. Anticancer activities of pterostilbene-isothiocyanate conjugate in breast cancer cells: involvement of PPARγ.

    Directory of Open Access Journals (Sweden)

    Kumar Nikhil

    Full Text Available Trans-3,5-dimethoxy-4'-hydroxystilbene (PTER, a natural dimethylated analog of resveratrol, preferentially induces certain cancer cells to undergo apoptosis and could thus have a role in cancer chemoprevention. Peroxisome proliferator-activated receptor γ (PPARγ, a member of the nuclear receptor superfamily, is a ligand-dependent transcription factor whose activation results in growth arrest and/or apoptosis in a variety of cancer cells. Here we investigated the potential of PTER-isothiocyanate (ITC conjugate, a novel class of hybrid compound (PTER-ITC synthesized by appending an ITC moiety to the PTER backbone, to induce apoptotic cell death in hormone-dependent (MCF-7 and -independent (MDA-MB-231 breast cancer cell lines and to elucidate PPARγ involvement in PTER-ITC action. Our results showed that when pre-treated with PPARγ antagonists or PPARγ siRNA, both breast cancer cell lines suppressed PTER-ITC-induced apoptosis, as determined by annexin V/propidium iodide staining and cleaved caspase-9 expression. Furthermore, PTER-ITC significantly increased PPARγ mRNA and protein levels in a dose-dependent manner and modulated expression of PPARγ-related genes in both breast cancer cell lines. This increase in PPARγ activity was prevented by a PPARγ-specific inhibitor, in support of our hypothesis that PTER-ITC can act as a PPARγ activator. PTER-ITC-mediated upregulation of PPARγ was counteracted by co-incubation with p38 MAPK or JNK inhibitors, suggesting involvement of these pathways in PTER-ITC action. Molecular docking analysis further suggested that PTER-ITC interacted with 5 polar and 8 non-polar residues within the PPARγ ligand-binding pocket, which are reported to be critical for its activity. Collectively, our observations suggest potential applications for PTER-ITC in breast cancer prevention and treatment through modulation of the PPARγ activation pathway.

  5. Enhanced toxicity and cellular uptake of methotrexate-conjugated nanoparticles in folate receptor-positive cancer cells by decorating with folic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate.

    Science.gov (United States)

    Junyaprasert, Varaporn Buraphacheep; Dhanahiranpruk, Sirithip; Suksiriworapong, Jiraphong; Sripha, Kittisak; Moongkarndi, Primchanien

    2015-12-01

    Folic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS-FOL) decorated methotrexate (MTX)-conjugated nanoparticles were developed for targeted delivery of MTX to folate receptor-expressed tumor cells. The synthesis of TPGS-FOL followed 3-step process. Firstly, the terminal hydroxyl group of TPGS was converted to sulfonyl chloride using mesyl chloride in comparison with nosyl and tosyl chlorides. The highest conversion efficiency and yield were obtained by mesyl chloride due to the formation of higher reactive intermediate in a presence of triethylamine. Secondly, the substitution of sulfonyl group by sodium azide produced considerably high yield with conversion efficiency of over 90%. Lastly, the coupling reaction of azido-substituted TPGS and propargyl folamide by click reaction resulted in 96% conjugation efficiency without polymer degradation. To fabricate the folate receptor-targeted nanoparticles, 10 and 20%mol MTX-conjugated PEGylated poly(ϵ-caprolactone) nanoparticles were decorated with TPGS-FOL. The size and size distribution of MTX-conjugated nanoparticles relatively increased with %MTX. The MTX release from the nanoparticles was accelerated in acidic medium with an increase of %MTX but retarded in physiological pH medium. The decoration of TPGS-FOL onto the nanoparticles slightly enlarged the size and size distribution of the nanoparticles; however, it did not affect the surface charge. The cytotoxicity and cellular uptake of MCF-7 cells demonstrated that 10% MTX-conjugated nanoparticles and FOL-decorated nanoparticles possessed higher toxicity and uptake efficiency than 20% MTX-conjugated nanoparticles and undecorated nanoparticles, respectively. The results indicated that FOL-10% MTX-conjugated nanoparticles exhibited potential targeted delivery of MTX to folate receptor-expressed cancer cells.

  6. Functional endothelial cells derived from embryonic stem cells labeled with HIV transactivator peptide-conjugated superparamagnetic nanoparticles

    Institute of Scientific and Technical Information of China (English)

    GAO Bin; FU Wei-guo; DONG Zhi-hui; FANG Zheng-dong; LIU Zhen-jie; SI Yi; ZHANG Xiang-man; WANG Yu-qi

    2011-01-01

    Background The development of regenerative therapies using derivatives of embryonic stem (ES) cells would be facilitated by a non-invasive method to monitor transplanted cells in vivo,for example,magnetic resonance imaging of cells labeled with superparamagnetic iron oxide (SPIO) nanoparticles.Although ES cells have been labeled with SPIO particles,the potential adverse effects of the label have not been fully examined.The objective of this study was to determine whether SPIO labeling affects murine ES cell viability,proliferation,or ability to differentiate into functional endothelial cells (ECs).Methods Cross-linked iron oxide (CLIO,an SPIO) was conjugated with human immunodeficiency virus transactivator of transcription (HIV-Tat) peptides,and murine ES cells were labeled with either CLiO-Tat,CLIO,or HIV-Tat.After labeling,ES cells were cultured for 4 days and FIk-1+ ES cells identified and sorted by immunocytochemistry and fluorescence activated cell sorting (FACS).FIk-1+ cells were raplated on fibronectin-coated dishes,and ECs were obtained by culturing these for 4 weeks in endothelial cell growth medium supplemented with vascular endothelial growth factor (VEGF).ES cell viability was determined using trypan blue exclusion,and the proportion of SPIO+ cells was evaluated using Prussian blue staining and transmission electron microscopy.After differentiation,the behavior and phenotype of ECs were analyzed by reverse transcription-polymerase chain reaction,flow cytometry,immunocytochemistry,Dil-labeled acetylated low-density lipoprotein (AcLDL) uptake,and Matrigel tube formation assay.Results CLIO-Tat was a highly effective label for ES cells,with >96% of cells incorporating the particles,and it did not alter the viability of the labeled cells.ECs derived from CLIO-Tat+ ES cells were very similar to murine aortic ECs in their morphology,expression of endothelial cell markers,ability to form vascular-like channels,and scavenging of AcLDL from the culture medium

  7. Conjugated linoleic acid or omega 3 fatty acids increase mitochondrial biosynthesis and metabolism in skeletal muscle cells

    OpenAIRE

    Vaughan Roger A; Garcia-Smith Randi; Bisoffi Marco; Conn Carole A; Trujillo Kristina A

    2012-01-01

    Abstract Background Polyunsaturated fatty acids are popular dietary supplements advertised to contribute to weight loss by increasing fat metabolism in liver, but the effects on overall muscle metabolism are less established. We evaluated the effects of conjugated linoleic acid (CLA) or combination omega 3 on metabolic characteristics in muscle cells. Methods Human rhabdomyosarcoma cells were treated with either DMSO control, or CLA or combination omega 3 for 24 or 48 hours. RNA was determine...

  8. Cyclic hexapeptide-conjugated nanoparticles enhance curcumin delivery to glioma tumor cells and tissue.

    Science.gov (United States)

    Zhang, Xuemei; Li, Xuejuan; Hua, Hongchen; Wang, Aiping; Liu, Wanhui; Li, Youxin; Fu, Fenghua; Shi, Yanan; Sun, Kaoxiang

    2017-01-01

    Glioma has one of the highest mortality rates among primary brain tumors. The clinical treatment for glioma is very difficult due to its infiltration and specific growth locations. To achieve improved drug delivery to a brain tumor, we report the preparation and in vitro and in vivo evaluation of curcumin nanoparticles (Cur-NPs). The cyclic hexapeptide c(RGDf(N-me) VK)-C (cHP) has increased affinity for cells that overexpress integrins and was designed to target Cur-NPs to tumors. Functional polyethyleneglycol-modified poly(d,l-lactide-co-glycolide) (PEG-PLGA) conjugated to cHP was synthesized, and targeted Cur-NPs were prepared using a self-assembly nanoprecipitation process. The physicochemical properties and the in vitro cytotoxicity, accuracy, and penetration capabilities of Cur-NPs targeting cells with high levels of integrin expression were investigated. The in vivo targeting and penetration capabilities of the NPs were also evaluated against glioma in rats using in vivo imaging equipment. The results showed that the in vitro cytotoxicity of the targeted cHP-modified curcumin nanoparticles (cHP/Cur-NPs) was higher than that of either free curcumin or non-targeted Cur-NPs due to the superior ability of the cHP/Cur-NPs to target tumor cells. The targeted cHP/Cur-NPs, c(RGDf(N-me)VK)-C-modified Cur-NPs, exhibited improved binding, uptake, and penetration abilities than non-targeting NPs for glioma cells, cell spheres, and glioma tissue. In conclusion, c(RGDf(N-me)VK)-C can serve as an effective targeting ligand, and cHP/Cur-NPs can be exploited as a potential drug delivery system for targeting gliomas.

  9. Ant 4,4, a polyamine-anthracene conjugate, induces cell death and recovery in human promyelogenous leukemia cells (HL-60).

    Science.gov (United States)

    Traquete, Rui; Ghani, Radiah A; Phanstiel, Otto; Wallace, Heather M

    2013-04-01

    One of the major problems in cancer therapy is the lack of specificity of chemotherapeutic agents towards cancer cells, resulting in adverse side effects. One means to counter this is to selectively deliver the drug to the cancer cell. Cancer cells accumulate increased concentrations of polyamines compared to normal cells, mainly through an increased uptake of preformed polyamines via the polyamine transport system (PTS). Furthermore, the non-stringent structural requirements of the PTS enable the transport of a range of polyamine-based molecules. Thus, the PTS can be used to transport compounds linked to polyamines selectively to cancer cells. In our laboratory, polyamine-anthracene conjugates have shown potent anti-tumour activity towards HL-60 cells. The aim of this study was to determine the cytotoxicity of Ant-4,4, a homospermidine-anthracene conjugate, and assess the long-term effects by determining whether cancer cells were able to recover from treatment. During exposure, Ant-4,4 was an effective growth-inhibitory agent in HL-60 cells decreasing viable cell number, protein and polyamine content. Evidence indicates concomitant cell-cycle arrest and increased apoptosis. Once the drug was removed, HL-60 cells recovered gradually over time. Increasing cell number, protein content and polyamine content, as well as diminished effects on cell-cycle and apoptotic stimuli were observed over time. These data suggest that, despite being an effective way of delivering anthracene, these polyamine conjugates do not exert long-lasting effects on HL-60 cells.

  10. The impact of B-cell perturbations on pneumococcal conjugate vaccine response in HIV-infected adults.

    Directory of Open Access Journals (Sweden)

    Thomas G Johannesson

    Full Text Available Untreated HIV infection results in severe perturbations of the B-cell population and hyporesponsiveness to vaccination. We studied associations between circulating B-cell subsets and antibody response to pneumococcal conjugate vaccine in treated and untreated HIV patients.Ninety-five HIV-infected adults were grouped according to antiretroviral therapy (ART and CD4+ cell count as follows: 20 ART-naïve (no prior ART, 62 ART-responders (received ART, and CD4 count >500 cells/µl, and 13 impaired responders (received ART for more than 3 years, and CD4 count <500 cells/µl. All subjects were immunized twice with double-dose 7-valent pneumococcal conjugate vaccine with or without 1 mg CPG 7909 (toll-like receptor 9 agonist at baseline and after three months. Pre-vaccination B-cell subpopulations were assessed by flow cytometry. Serum IgG concentrations for vaccine serotypes were quantified by ELISA at baseline and 3, 4, and 9 months post-vaccination. ART responders had more isotype-switched memory B cells and more marginal-zone (MZ-like B cells compared with impaired responders. Furthermore, ART-naïve patients had higher concentration of transitional B cells and plasmablasts compared with B cells of other patient groups. The concentration of MZ-like, isotype switched memory cells and plasmablasts correlated positively with post-vaccination IgG concentration at 3, 4, and 9 months. Low concentrations of isotype-switched memory B cells was the strongest independent predictor of poor pneumococcal conjugate vaccine responsiveness, emphasizing that B-cell subset disturbances are associated with poor vaccine response among HIV-infected patients.

  11. M-cell targeted delivery of recombinant hepatitis B surface antigen using cholera toxin B subunit conjugated bilosomes.

    Science.gov (United States)

    Shukla, Anshuman; Katare, O P; Singh, Bhupinder; Vyas, Suresh P

    2010-01-29

    The present study aims to improve upon our earlier findings with bilosomes as potential delivery vehicle through oral route for recombinant hepatitis B surface antigen (HBsAg). The work entails the conjugation of bilosomal system with cholera toxin B subunit (CTB) to increase transmucosal uptake via M-cell specific delivery approach. The study encompasses the development and characterization of HBsAg-loaded CTB-conjugated system for percent antigen entrapment, size, shape, and stability in SGF (USP, pH 1.2), SIF (USP, pH 7.5) and in bile salt solutions. Biological activity of CTB, subsequent to conjugation, was verified by hemagglutination test. Anti-HBsAg IgG response in serum and anti-HBsAg sIgA in various body secretions were estimated using ELISA, following oral immunization with 10 microg dose-loaded CTB-conjugated bilosomes (CTB2) and 20 microg dose-loaded CTB-conjugated bilosomes (CTB1) in BALB/c mice. The results showed that CTB1 produced anti-HBsAg IgG antibody titre response comparable to that of the intramuscular (i.m.) injection of 10 microg of alum-adsorbed HBsAg. Moreover, all the bilosomal preparations elicited measurable sIgA vis-à-vis negligible response with i.m. administered HBsAg. Thus, HBsAg-loaded CTB-conjugated bilosomes provide a promising potential for targeted oral immunization against hepatitis B. 2009 Elsevier B.V. All rights reserved.

  12. π-Conjugated Materials as the Hole-Transporting Layer in Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Alexandre Gheno

    2016-01-01

    Full Text Available Hybrid organometal halide perovskites have attracted much attention these past four years as the new active layer for photovoltaic applications. Researches are now intensively focused on the stability issues of these solar cells, the process of fabrication and the design of innovative materials to produce efficient perovskite devices. In this review, we highlight the recent progress demonstrated in 2015 in the design of new π-conjugated organic materials used as hole transporters in such solar cells. Indeed, several of these “synthetic metals” have been proposed to play this role during the last few years, in an attempt to replace the conventional 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino-9,9′-spirobifluorene (Spiro-OMeTAD reference. Organic compounds have the benefits of low production costs and the abundance of raw materials, but they are also crucial components in order to address some of the stability issues usually encountered by this type of technology. We especially point out the main design rules to reach high efficiencies.

  13. Investigation of the apoptotic pathway induced by benzimidazole-oxindole conjugates against human breast cancer cells MCF-7.

    Science.gov (United States)

    Lakshma Nayak, Vadithe; Nagaseshadri, Bobburi; Vishnuvardhan, M V P S; Kamal, Ahmed

    2016-07-15

    In our previous studies, benzimidazole-oxindole conjugates were synthesized and evaluated by National Cancer Institute (NCI) for their cytotoxic activity and the new molecules like 5c and 5p were considered as potential leads. These conjugates arrested the cell cycle at G2/M phase and inhibited tubulin polymerization. These observations prompted us to investigate the apoptotic mechanism induced by these lead molecules against human breast cancer cells (MCF-7). Studies like measurement of mitochondrial membrane potential (ΔΨm), generation of reactive oxygen species (ROS) and Annexin V-FITC assay revealed that these compounds induced mitochondrial mediated (intrinsic apoptotic pathway) apoptosis in human breast cancer cells. It was further confirmed by western blot analysis of pro apoptotic protein Bax, anti apoptotic protein Bcl-2, cytochrome c release, caspase-9 activity and cleavage of PARP.

  14. Arginine-glycine-aspartic acid-polyethylene glycol-polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture.

    Science.gov (United States)

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine-glycine-aspartic acid (RGD) peptide. Our studies demonstrate that RGD-polyethylene glycol (PEG)-PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT-MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system.

  15. Microparticulate β-glucan vaccine conjugates phagocytized by dendritic cells activate both naïve CD4 and CD8 T cells in vitro.

    Science.gov (United States)

    Berner, Vanessa K; duPre, Sally A; Redelman, Doug; Hunter, Kenneth W

    2015-01-01

    Microparticulate β-glucan (MG) conjugated to vaccine antigen has been shown to serve as an effective adjuvant in vivo. To further study antigen presentation by MG:vaccine conjugates, bone marrow-derived dendritic cells (BMDC) were treated with MG conjugated to ovalbumin (OVA), then interacted with splenocytes from DO11.10 transgenic mice expressing an OVA peptide-specific T cell receptor. BMDC treated with MG:OVA induced significantly higher numbers of activated (CD25+CD69+) OVA-specific CD4+ T cells than BMDC treated with OVA alone. BMDC treated with MG:OVA upregulated CD86 and CD40 expression as well as MG alone, indicating that conjugation of OVA does not alter the immunostimulatory capacity of MG. Activation of CD8+ OVA-specific OT-1 cells showed that MG:OVA is also capable of enhancing cross-presentation by BMDC to CD8+ cytotoxic T cells. These results show that MG acts as an adjuvant to enhance antigen presentation by dendritic cells to naïve, antigen-specific CD4 and CD8 T cells.

  16. Enzyme-triggered delivery of chlorambucil from conjugates based on the cell-penetrating peptide BP16.

    Science.gov (United States)

    Soler, Marta; González-Bártulos, Marta; Figueras, Eduard; Ribas, Xavi; Costas, Miquel; Massaguer, Anna; Planas, Marta; Feliu, Lidia

    2015-02-07

    The undecapeptide KKLFKKILKKL-NH2 (BP16) is a non-toxic cell-penetrating peptide (CPP) that is mainly internalized into cancer cells through a clathrin dependent endocytic mechanism and localizes in late endosomes. Moreover, this CPP is able to enhance the cellular uptake of chlorambucil (CLB) improving its cytotoxicity. In this work, we further explored the cell-penetrating properties of BP16 and those of its arginine analogue BP308. We investigated the influence on the cytotoxicity and on the cellular uptake of conjugating CLB at the N- or the C-terminal end of these undecapeptides. The effect of incorporating the cathepsin B-cleavable sequence Gly-Phe-Leu-Gly in CLB-BP16 and CLB-BP308 conjugates was also evaluated. The activity of CLB was significantly improved when conjugated at the N- or the C-terminus of BP16, or at the N-terminus of BP308. While CLB alone was not active (IC50 of 73.7 to >100 μM), the resulting conjugates displayed cytotoxic activity against CAPAN-1, MCF-7, PC-3, 1BR3G and SKMEL-28 cell lines with IC50 values ranging from 8.7 to 25.5 μM. These results were consistent with the internalization properties observed for the corresponding 5(6)-carboxyfluorescein-labeled conjugates. The presence of the tetrapeptide Gly-Phe-Leu-Gly at either the N- or the C-terminus of CLB-BP16 conjugates further increased the efficacy of CLB (IC50 of 3.6 to 16.2 μM), which could be attributed to its selective release in the lysosomal compartment. Enzymatic assays with cathepsin B showed the release of CLB-Gly-OH from these sequences within a short time. Therefore, the combination of BP16 with an enzymatic cleavable sequence can be used as a drug delivery system for the effective uptake and release of drugs in cancer cells.

  17. Atomic force microscopy recognition of protein A on Staphylococcus aureus cell surfaces by labelling with IgG–Au conjugates

    Directory of Open Access Journals (Sweden)

    Elena B. Tatlybaeva

    2013-11-01

    Full Text Available The labelling of functional molecules on the surface of bacterial cells is one way to recognize the bacteria. In this work, we have developed a method for the selective labelling of protein A on the cell surfaces of Staphylococcus aureus by using nanosized immunogold conjugates as cell-surface markers for atomic force microscopy (AFM. The use of 30-nm size Au nanoparticles conjugated with immunoglobulin G (IgG allowed the visualization, localization and distribution of protein A–IgG complexes on the surface of S. aureus. The selectivity of the labelling method was confirmed in mixtures of S. aureus with Bacillus licheniformis cells, which differed by size and shape and had no IgG receptors on the surface. A preferential binding of the IgG–Au conjugates to S. aureus was obtained. Thus, this novel approach allows the identification of protein A and other IgG receptor-bearing bacteria, which is useful for AFM indication of pathogenic microorganisms in poly-component associations.

  18. C2-streptavidin mediates the delivery of biotin-conjugated tumor suppressor protein p53 into tumor cells.

    Science.gov (United States)

    Fahrer, Jörg; Schweitzer, Brigitte; Fiedler, Katja; Langer, Torben; Gierschik, Peter; Barth, Holger

    2013-04-17

    We have previously generated a recombinant C2-streptavidin fusion protein for the delivery of biotin-labeled molecules of low molecular weight into the cytosol of mammalian cells. A nontoxic moiety of Clostridium botulinum C2 toxin mediates the cellular uptake, whereas the streptavidin unit serves as a binding platform for biotin-labeled cargo molecules. In the present study, we used the C2-streptavidin transporter to introduce biotin-conjugated p53 protein into various mammalian cell lines. The p53 tumor suppressor protein is inactivated in many human cancers by multiple mechanisms and therefore the restoration of its activity in tumor cells is of great therapeutic interest. Recombinant p53 was expressed in insect cells and biotin-labeled. Biotin-p53 retained its specific high-affinity DNA-binding as revealed by gel-shift analysis. Successful conjugation of biotin-p53 to the C2-streptavidin transporter was monitored by an overlay blot technique and confirmed by real-time surface plasmon resonance, providing a KD-value in the low nM range. C2-streptavidin significantly enhanced the uptake of biotin-p53 into African Green Monkey (Vero) epithelial cells as shown by flow cytometry. Using cell fractionation, the cytosolic translocation of biotin-p53 was detected in Vero cells as well as in HeLa cervix carcinoma cells. In line with this finding, confocal microscopy displayed cytoplasmic staining of biotin-p53 in HeLa and HL60 leukemia cells. Internalized biotin-p53 partially colocalized with early endosomes, as confirmed by confocal microscopy. In conclusion, our results demonstrate the successful conjugation of biotin-p53 to C2-streptavidin and its subsequent receptor-mediated endocytosis into different human tumor cell lines.

  19. Repression of hydrogen uptake using conjugated oligoelectrolytes in microbial electrolysis cells

    KAUST Repository

    Hou, Huijie

    2014-11-01

    Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. DSBN+, a conjugated oligoelectrolyte (COE), was added to microbial electrolysis cells (MECs) to improve hydrogen recovery. The volume of hydrogen gas recovered in a fedbatch cycle of mixed culture MECs increased by 126× compared to controls (no COE addition), mainly by preventing the loss of hydrogen to methane production. Performance in pure culture MECs fed with Geobacter sulfurreducens increased by factors of 10.5 in terms of energy yield, 2.1 in COD removal, and 11.8 in hydrogen yield. Hydrogen gas recycling was reduced, and the volume of hydrogen gas recovered increased by 6.5× compared to controls. Minimal methane production and a lack of hydrogen gas uptake by G. sulfurreducens suggested that the COEs increased hydrogen recoveries by interfering with hydrogen uptake by hydrogenotrophic methanogens but also by exoelectrogenic bacteria. COEs may therefore be useful for inhibiting the activities of certain hydrogenases, although the mechanism of inhibition needs further investigation.

  20. Antibody-antigen-adjuvant conjugates enable co-delivery of antigen and adjuvant to dendritic cells in cis but only have partial targeting specificity.

    Directory of Open Access Journals (Sweden)

    Martin Kreutz

    Full Text Available Antibody-antigen conjugates, which promote antigen-presentation by dendritic cells (DC by means of targeted delivery of antigen to particular DC subsets, represent a powerful vaccination approach. To ensure immunity rather than tolerance induction the co-administration of a suitable adjuvant is paramount. However, co-administration of unlinked adjuvant cannot ensure that all cells targeted by the antibody conjugates are appropriately activated. Furthermore, antigen-presenting cells (APC that do not present the desired antigen are equally strongly activated and could prime undesired responses against self-antigens. We, therefore, were interested in exploring targeted co-delivery of antigen and adjuvant in cis in form of antibody-antigen-adjuvant conjugates for the induction of anti-tumour immunity. In this study, we report on the assembly and characterization of conjugates consisting of DEC205-specific antibody, the model antigen ovalbumin (OVA and CpG oligodeoxynucleotides (ODN. We show that such conjugates are more potent at inducing cytotoxic T lymphocyte (CTL responses than control conjugates mixed with soluble CpG. However, our study also reveals that the nucleic acid moiety of such antibody-antigen-adjuvant conjugates alters their binding and uptake and allows delivery of the antigen and the adjuvant to cells partially independently of DEC205. Nevertheless, antibody-antigen-adjuvant conjugates are superior to antibody-free antigen-adjuvant conjugates in priming CTL responses and efficiently induce anti-tumour immunity in the murine B16 pseudo-metastasis model. A better understanding of the role of the antibody moiety is required to inform future conjugate vaccination strategies for efficient induction of anti-tumour responses.

  1. EFFECT OF CIS-9, TRANS-11-CONJUGATED LINOLEIC ACID ON CELL CYCLE OF MAMMARY ADENOCARCINOMA CELLS(MCF-7)

    Institute of Scientific and Technical Information of China (English)

    刘家仁; 陈炳卿; 韩晓辉; 杨艳梅; 郑玉梅; 刘瑞海

    2002-01-01

    Objective: To determine the effect of cis-9, trans-1 1-conjugated linoleic acid on the cell cycle of mammary cancer cells (MCF-7) and the possible mechanism of the inhibitory effect of c9,t11-CLA. Methods: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA , cyclin A, B1, D1, p16ink4a and p21cip/waf1 of MCF-7 cells at various c9,t11-CLA concentrations (25μM, 50μM, 100μM and 200μM), at 24h and 48h. 96% ethand was used as negative control. Results: The cell growth and DNA synthesis of MCF-7 cells were inhibited by c9,t11-CLA. After treatment with various doses of c9,t11-CLA mentioned above for 8 days, the inhibition frequency was 27.18%, 35.43%, 91.05%, and 92.86%, respectively. Inhibitory effect of c9,t11-CLA on DNA synthesis (except for 25μM, 24h) was demonstrated by significantly less incorporation of 3H-TdR than the negative control (P<0.05 and P<0.01). To further investigate the influence of the cell cycle progression, we found that c9,t11-CLA may arrest the cell cycle of MCF-7 cells. Immunocytochemical staining demonstrated that incubation with different concentration of c9,t11-CLA at various times significantly decreased the expression of PCNA, Cyclin A, B1, D1 in MCF-7 cells compared to the negative control (P<0.01), whereas the expression of p16ink4a and p21cip/waf1, cyclin-dependent kinases inhibitors (CDKI), were increased. Conclusions: The cell growth and proliferation of MCF-7 cells is inhibited by c9,t11-CLA via blocking cell cycle, accompanying reduced expression of cyclin A, B1, D1 and enhanced expression of CDKI (p16ink4a and p21cip/wafl).

  2. Effective in vitro gene delivery to murine cancerous brain cells using carbon nanotube-polyethylenimine conjugates

    Directory of Open Access Journals (Sweden)

    Azadeh Hashem Nia

    2015-04-01

    Conclusion: Conjugation of PEI with carbon nanotube les to new vectors with lowered cytotoxicity and higher transfection efficiency. The highest transfection efficiency was obtained with the lowest molecular weight PEI.

  3. A new daunomycin-peptide conjugate: synthesis, characterization and the effect on the protein expression profile of HL-60 cells in vitro.

    Science.gov (United States)

    Orbán, Erika; Manea, Marilena; Marquadt, Andreas; Bánóczi, Zoltán; Csík, Gabriella; Fellinger, Erzsébet; Bosze, Szilvia; Hudecz, Ferenc

    2011-10-19

    Daunomycin (Dau) is a DNA-binding antineoplastic agent in the treatment of various types of cancer, such as osteosarcomas and acute myeloid leukemia. One approach to improve its selectivity and to decrease the side effects is the conjugation of Dau with oligopeptide carriers, which might alter the drug uptake and intracellular fate. Here, we report on the synthesis, characterization, and in vitro biological properties of a novel conjugate in which Dau is attached, via an oxime bond, to one of the cancer specific small peptides (LTVSPWY) selected from a random phage peptide library. The in vitro cytostatic effect and cellular uptake of Dau═Aoa-LTVSPWY-NH(2) conjugate were studied on various human cancer cell lines expressing different levels of ErbB2 receptor which could be targeted by the peptide. We found that the new daunomycin-peptide conjugate is highly cytostatic and could be taken up efficiently by the human cancer cells studied. However, the conjugate was less effective than the free drug itself. RP-HPLC data indicate that the conjugate is stable at least for 24 h in the pH 2.5-7.0 range of buffers, as well as in cell culture medium. The conjugate in the presence of rat liver lysosomal homogenate, as indicated by LC-MS analysis, could be degraded. The smallest, Dau-containing metabolite (Dau═Aoa-Leu-OH) identified and prepared expresses DNA-binding ability. In order to get insight on the potential mechanism of action, we compared the protein expression profile of HL-60 human leukemia cells after treatment with the free and peptide conjugated daunomycin. Proteomic analysis suggests that the expression of several proteins has been altered. This includes three proteins, whose expression was lower (tubulin β chain) or markedly higher (proliferating cell nuclear antigen and protein kinase C inhibitor protein 1) after administration of cells with Dau-conjugate vs free drug.

  4. Conjugation of a cell-penetrating peptide to parathyroid hormone affects its structure, potency, and transepithelial permeation

    DEFF Research Database (Denmark)

    Kristensen, Mie; de Groot, Anne Marit; Berthelsen, Jens;

    2015-01-01

    hormone, i.e. PTH(1-34), and to evaluate the effect with regards to secondary structure, potency in Saos-2 cells, immunogenicity, safety as well as the transepithelial permeation across monolayers by using the Caco-2 cell culture model. Further, co-administration of CPP and PTH(1-34) as an alternative......Delivery of therapeutic peptides and proteins by the use of cell-penetrating peptides (CPPs) as carriers has been suggested as a feasible strategy. The aim of the present study was to investigate the effect of conjugating a series of well-known CPPs to the biologically active part of parathyroid...

  5. Lectin Conjugated Gold Nanoparticle-based Colorimetric Assay for Studying the Interactions of Antibiotic with Living Cell

    Institute of Scientific and Technical Information of China (English)

    WANG Jin-e; WANG Cheng-ke; LIU Dian-jun; WANG Zhen-xin

    2011-01-01

    The interactions of antibiotic with living cells were studied by iectin conjugated gold nanoparticles(GNPs)based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNPs are able to employ as indicators for monitoring the antibiotic induced changes of glycosyl complexes. The interactions of a well known antibiotic, tunicamycin, with two different cell lines, HeLa and SHG-44, were selected to establish this assay.In the presence of tunicamycin, the dose- and time-dependence on the decreasing of binding affinity of lectin conjugated GNPs with living cells were demonstrated by conventional microscopic and UV-Vis spectroscopic studies. The experimental result demonstrates that our approach can be used to identify antibiotic induced expression difference of glycosyl complexes on different cellular surfaces and determine drug activity quantitatively. For further confirming the capability of the GNP-based assay, the system was also studied by confocal laser scanning microscopy(CLSM)and classic flow cytometry(FCM) assay, and satisfactory results were obtained.

  6. Targeting Mast Cells and Basophils with Anti-FcεRIα Fab-Conjugated Celastrol-Loaded Micelles Suppresses Allergic Inflammation.

    Science.gov (United States)

    Peng, Xia; Wang, Juan; Li, Xianyang; Lin, Lihui; Xie, Guogang; Cui, Zelin; Li, Jia; Wang, Yuping; Li, Li

    2015-12-01

    Mast cells and basophils are effector cells in the pathophysiology of allergic diseases. Targeted elimination of these cells may be a promising strategy for the treatment of allergic disorders. Our present study aims at targeted delivery of anti-FcεRIα Fab-conjugated celastrol-loaded micelles toward FcεRIα receptors expressed on mast cells and basophils to have enhanced anti-allergic effect. To achieve this aim, we prepared celastrol-loaded (PEO-block-PPO-block-PEO, Pluronic) polymeric nanomicelles using thin-film hydration method. The anti-FcεRIα Fab Fragment was then conjugated to carboxyl groups on drug-loaded micelles via EDC amidation reaction. The anti-FcεRIα Fab-conjugated celastrol-loaded micelles revealed uniform particle size (93.43 ± 12.93 nm) with high loading percentage (21.2 ± 1.5% w/w). The image of micelles showed oval and rod like. The anti-FcεRIα Fab-conjugated micelles demonstrated enhanced cellular uptake and cytotoxity toward target KU812 cells than non-conjugated micelles in vitro. Furthermore, diffusion of the drug into the cells allowed an efficient induction of cell apoptosis. In mouse model of allergic asthma, treatment with anti-FcεRIα Fab-conjugated micelles increased lung accumulation of micelles, and significantly reduced OVA-sIgE, histamine and Th2 cytokines (IL-4, IL-5, TNF-α) levels, eosinophils infiltration and mucus production. In addition, in mouse model of passive cutaneous anaphylaxis, anti-FcεRIα Fab-conjugated celastrol-loaded micelles treatment significantly decreased extravasated evan's in the ear. These results indicate that anti-FcεRIα Fab-conjugated celastrol-loaded micelles can target and selectively kill mast cells and basophils which express FcεRIα, and may be efficient reagents for the treatment of allergic disorders and mast cell related diseases.

  7. Design of perylene diimides for organic solar cell: Effect of molecular steric hindrance and extended conjugation

    Energy Technology Data Exchange (ETDEWEB)

    Kozma, Erika, E-mail: erika.kozma@ismac.cnr.it [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Kotowski, Dariusz; Catellani, Marinella; Luzzati, Silvia [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Cavazzini, Marco; Bossi, Alberto; Orlandi, Simonetta [Istituto di Scienze e Tecnologie Molecolari, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Bertini, Fabio [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy)

    2015-08-01

    Core-substituted perylene diimides (PDI) are promising candidates as n-type semiconductor materials for organic photovoltaics. The chemical functionalization of perylene diimides in the bay positions is a versatile tool to obtain a series of electron acceptor materials with tunable electron affinity. These materials usually feature a donor-acceptor D-A structure in which the electron withdrawing PDI core is covalently linked with different electron donating chemical groups. The structural and electronic properties of the substituents define and modulate the optical/electrical properties of the semiconductor and the performance as photovoltaic material. In this work we designed two PDI molecules with D-A-D structure using spirobifluorene group as substituent directly linked to the perylene core (PDI-SF) and with insertion of a bithiophene moiety (PDI-BSF). In both molecules we found a reduced tendency to form aggregates in the solid state thanks to the cross-shaped rigid structure and strong steric hindrance of the spirobifluorene group. Additionally, in the case of PDI-BSF the presence of the bithiophene linker contributes significantly to extend the conjugation, resulting in a panchromatic absorption in the whole visible to NIR region. We present the synthesis of these materials and their characterisation in terms of absorption spectroscopy, cyclic voltammetry and computational calculations. Finally we show preliminary results of their use as active components in P3HT/PDIs bulk heterojunction solar cells. - Highlights: • New D-A-D n-type materials have been synthesized. • PDI-SF and PDI-BSF were used as acceptors in organic solar cells. • Performances of 1.32% were achieved in blend with P3HT in a BHJ conventional architecture.

  8. Small ubiquitin-like modifier 1-3 conjugation [corrected] is activated in human astrocytic brain tumors and is required for glioblastoma cell survival.

    Science.gov (United States)

    Yang, Wei; Wang, Liangli; Roehn, Gabriele; Pearlstein, Robert D; Ali-Osman, Francis; Pan, Hongjie; Goldbrunner, Roland; Krantz, Matthew; Harms, Christoph; Paschen, Wulf

    2013-01-01

    Small ubiquitin-like modifier (SUMO1-3) constitutes a group of proteins that conjugate to lysine residues of target proteins thereby modifying their activity, stability, and subcellular localization. A large number of SUMO target proteins are transcription factors and other nuclear proteins involved in gene expression. Furthermore, SUMO conjugation plays key roles in genome stability, quality control of newly synthesized proteins, proteasomal degradation of proteins, and DNA damage repair. Any marked increase in levels of SUMO-conjugated proteins is therefore expected to have a major impact on the fate of cells. We show here that SUMO conjugation is activated in human astrocytic brain tumors. Levels of both SUMO1- and SUMO2/3-conjugated proteins were markedly increased in tumor samples. The effect was least pronounced in low-grade astrocytoma (WHO Grade II) and most pronounced in glioblastoma multiforme (WHO Grade IV). We also found a marked rise in levels of Ubc9, the only SUMO conjugation enzyme identified so far. Blocking SUMO1-3 conjugation in glioblastoma cells by silencing their expression blocked DNA synthesis, cell growth, and clonogenic survival of cells. It also resulted in DNA-dependent protein kinase-induced phosphorylation of H2AX, indicative of DNA double-strand damage, and G(2) /M cell cycle arrest. Collectively, these findings highlight the pivotal role of SUMO conjugation in DNA damage repair processes and imply that the SUMO conjugation pathway could be a new target of therapeutic intervention aimed at increasing the sensitivity of glioblastomas to radiotherapy and chemotherapy.

  9. Synthesis and study of benzothiazole conjugates in the control of cell proliferation by modulating Ras/MEK/ERK-dependent pathway in MCF-7 cells.

    Science.gov (United States)

    Kamal, Ahmed; Faazil, Shaikh; Ramaiah, M Janaki; Ashraf, Md; Balakrishna, M; Pushpavalli, S N C V L; Patel, Nibedita; Pal-Bhadra, Manika

    2013-10-15

    By applying a methodology, a series of benzothiazole-pyrrole based conjugates (4a-r) were synthesized and evaluated for their antiproliferative activity. Compounds such as 4a, 4c, 4e, 4g-j, 4m, 4n, 4o and 4r exhibited significant cytotoxic effect in the MCF-7 cell line. Cell cycle effects were examined for these conjugates at 2 μM as well as 4 μM concentrations and FACS analysis show an increase of G2/M phase cells with concomitant decrease of G1 phase cells thereby indicating G2/M cell cycle arrest by them. Interestingly 4o and 4r are effective in causing apoptosis in MCF-7 cells. Moreover, 4o showed down regulation of oncogenic expression of Ras and its downstream effector molecules such as MEK1, ERK1/2, p38 MAPK and VEGF. The apoptotic aspect of this conjugate is further evidenced by increased expression of caspase-9 in MCF-7 cells. Hence these small molecules have the potential to control both the cell proliferation as well as the invasion process in the highly malignant breast cancers.

  10. Robust Nanoparticle-DNA Conjugates Based on Mussel-Inspired Polydopamine Coating for Cell Imaging and Tailored Self-Assembly.

    Science.gov (United States)

    Wang, Chenxu; Zhou, Jiajing; Wang, Peng; He, Wenshan; Duan, Hongwei

    2016-03-16

    We have demonstrated that mussel-inspired polydopamine can serve as an intermediate coating layer for covalently attaching oligonucleotides on nanostructures of diverse chemical nature, which are made possible by the universal adhesion and spontaneous reactivity of polydopamine. Our results have shown that polydopamine can strongly bond to representative nanoparticles (i.e., Au nanoparticles and magnetic polymer nanobeads) and form a thin layer of coating that allows for attachment of commercially available DNA with thiol or amine end functionality. The resulting DNA-nanoparticle conjugates not only show excellent chemical and thermal stability and high loading density of DNA, but the linked DNA also maintain their biological functions in directing cancer cell targeting and undergo DNA hybridization to form multifunctional magnetic core-plasmonic satellite assemblies. The generally applicable strategy opens new opportunities for easy adoption of DNA-nanoparticle conjugates for broad applications in biosensors and nanomedicine.

  11. Murid Gammaherpesvirus Latency-Associated Protein M2 Promotes the Formation of Conjugates between Transformed B Lymphoma Cells and T Helper Cells.

    Directory of Open Access Journals (Sweden)

    Diana Fontinha

    Full Text Available Establishment of persistent infection in memory B cells by murid herpesvirus-4 (MuHV-4 depends on the proliferation of latently infected germinal center B cells, for which T cell help is essential. Whether the virus is capable of modulating B-T helper cell interaction for its own benefit is still unknown. Here, we investigate if the MuHV-4 latency associated M2 protein, which assembles multiprotein complexes with B cell signaling proteins, plays a role. We observed that M2 led to the upregulation of adhesion and co-stimulatory molecules in transduced B cell lines. In an MHC-II restricted OVA peptide-specific system, M2 polarized to the B-T helper contact zone. Furthermore, it promoted B cell polarization, as demonstrated by the increased proximity of the B cell microtubule organizing center to the interface. Consistent with these data, M2 promoted the formation of B-T helper cell conjugates. In an in vitro competition assay, this translated into a competitive advantage, as T cells preferentially conjugated with M2-expressing B cells. However, expression of M2 alone in B cells was not sufficient to lead to T cell activation, as it only occurred in the presence of specific peptide. Taken together, these findings support that M2 promotes the formation of B-T helper cell conjugates. In an in vivo context this may confer a competitive advantage to the infected B cell in acquisition of T cell help and initiation of a germinal center reaction, hence host colonization.

  12. Peptide nucleic acid (PNA) cell penetrating peptide (CPP) conjugates as carriers for cellular delivery of antisense oligomers

    DEFF Research Database (Denmark)

    Shiraishi, Takehiko; Nielsen, Peter E

    2012-01-01

    We have explored the merits of a novel delivery strategy for the antisense oligomers based on cell penetrating peptide (CPP) conjugated to a carrier PNA with sequence complementary to part of the antisense oligomer. The effect of these carrier CPP-PNAs was evaluated by using antisense PNA targeting...... splicing correction of the mutated luciferase gene in the HeLa pLuc705 cell line, reporting cellular (nuclear) uptake of the antisense PNA via luciferase activity measurement. Carrier CPP-PNA constructs were studied in terms of construct modification (with octaarginine and/or decanoic acid) and carrier PNA...

  13. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria; Kesters, Jurgen; Defour, Maxime

    2016-01-01

    The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT) or thiazolo[5,4-d......, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same.The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime...

  14. lmmunofiuorescent Labeling of Human HepG2 Cells with CdTe Quantum Dot Probe Conjugated with Anti-pan CK MAb

    Institute of Scientific and Technical Information of China (English)

    SUI Yu-jie; ZHANG Gui-zhen; WANG Qian; WANG Ya-li; WU Mei; DU Zhen-wu; ZHANG Jie; JIANG Ri-hua

    2011-01-01

    A relatively sensitive, specific, and photostable method for the detection of cytokeratin of cancer cells via conjugation with cadmium telluride quantum dots(CdTe QDs) was described. Water soluble CdTe QDs were conjugated to anti-pan-cytokeratin(CK) monoclonal antibody(MAb) through coupling reagent [1-ethyi-3-(3-dimethylamino propyl)carbodiimide, EDC] and the conjugates were purified by dialysis. The expression of pan CK protein in HepG2 cells was observed by immunocytochemistry and direct immunofluorescence via QDs-Ab conjugates respectively. Fluorescence intensity and photostability of QDs were compared with those of FITC(fiuorescein isothiocyanate). The results show that the QDs-Ab conjugates recognized specifically pan CK protein in HepG2 cells. Compared with FITC, CdTe QDs had higher brightness and photostability without obvious photobleaching under continuous exciting light illumination for 30 min and after the placement at room temperature for 3 d. The results indicate that conjugates of CdTe quantum dot with anti-pan CK MAb can be used for labeling cancer cells derived from epithelial tissues, which provides the basis for the detection of circulating tumor cells(CTCs).

  15. The impact of B-cell perturbations on pneumococcal conjugate vaccine response in HIV-infected adults.

    Science.gov (United States)

    Johannesson, Thomas G; Søgaard, Ole S; Tolstrup, Martin; Petersen, Mikkel S; Bernth-Jensen, Jens M; Østergaard, Lars; Erikstrup, Christian

    2012-01-01

    Untreated HIV infection results in severe perturbations of the B-cell population and hyporesponsiveness to vaccination. We studied associations between circulating B-cell subsets and antibody response to pneumococcal conjugate vaccine in treated and untreated HIV patients.Ninety-five HIV-infected adults were grouped according to antiretroviral therapy (ART) and CD4+ cell count as follows: 20 ART-naïve (no prior ART), 62 ART-responders (received ART, and CD4 count >500 cells/µl), and 13 impaired responders (received ART for more than 3 years, and CD4 count CPG 7909 (toll-like receptor 9 agonist) at baseline and after three months. Pre-vaccination B-cell subpopulations were assessed by flow cytometry. Serum IgG concentrations for vaccine serotypes were quantified by ELISA at baseline and 3, 4, and 9 months post-vaccination. ART responders had more isotype-switched memory B cells and more marginal-zone (MZ)-like B cells compared with impaired responders. Furthermore, ART-naïve patients had higher concentration of transitional B cells and plasmablasts compared with B cells of other patient groups. The concentration of MZ-like, isotype switched memory cells and plasmablasts correlated positively with post-vaccination IgG concentration at 3, 4, and 9 months. Low concentrations of isotype-switched memory B cells was the strongest independent predictor of poor pneumococcal conjugate vaccine responsiveness, emphasizing that B-cell subset disturbances are associated with poor vaccine response among HIV-infected patients.

  16. N-Acetylgalactosamine-Targeted Delivery of Dendrimer-Doxorubicin Conjugates Influences Doxorubicin Cytotoxicity and Metabolic Profile in Hepatic Cancer Cells.

    Science.gov (United States)

    Kuruvilla, Sibu P; Tiruchinapally, Gopinath; ElAzzouny, Mahmoud; ElSayed, Mohamed E H

    2017-03-01

    This study describes the development of targeted, doxorubicin (DOX)-loaded generation 5 (G5) polyamidoamine dendrimers able to achieve cell-specific DOX delivery and release into the cytoplasm of hepatic cancer cells. G5 is functionalized with poly(ethylene glycol) (PEG) brushes displaying N-acetylgalactosamine (NAcGal) ligands to target hepatic cancer cells. DOX is attached to G5 through one of two aromatic azo-linkages, L3 or L4, achieving either P1 ((NAcGalβ -PEGc)16.6 -G5-(L3-DOX)11.6 ) or P2 ((NAcGalβ -PEGc)16.6 -G5-(L4-DOX)13.4 ) conjugates. After confirming the conjugates' biocompatibility, flow cytometry studies show P1/P2 achieve 100% uptake into hepatic cancer cells at 30-60 × 10(-9) m particle concentration. This internalization correlates with cytotoxicity against HepG2 cells with 50% inhibitory concentration (IC50 ) values of 24.8, 1414.0, and 237.8 × 10(-9) m for free DOX, P1, and P2, respectively. Differences in cytotoxicity prompted metabolomics analysis to identify the intracellular release behavior of DOX. Results show that P1/P2 release alternative DOX metabolites than free DOX. Stable isotope tracer studies show that the different metabolites induce different effects on metabolic cycles. Namely, free DOX reduces glycolysis and increases fatty acid oxidation, while P1/P2 increase glycolysis, likely as a response to high oxidative stress. Overall, P1/P2 conjugates offer a platform drug delivery technology for improving hepatic cancer therapy.

  17. Synthesis and photophysical characterization of conjugated molecules for potential solar cell uses

    Science.gov (United States)

    Chudomel, John Matthew

    Three new strategies were successfully pursued for the synthesis of defined length oligomers of p-phenylene-vinylene. These strategies are interchangeable and allow the fast and efficient synthesis of a wide variety of oligomers with a number of different substituents. An assortment of new molecules and oligomers were synthesized and characterized during this study to prove the effectiveness of each strategy. The new strategies were compared to previous methodology for making similar oligomers. A large, nonplanar, conjugated chromophore 9BrH was synthesized based on an adaptation of previous work. 9BrH and its synthetic precursor, pre9BrH, were characterized using X-Ray crystallography. The experimentally determined conformation and bond lengths of 9BrH were compared to previous theoretical studies and confirmed much of what was predicted. The 9BrH chromophore was stockpiled for use in additional studies. Three highly twisted triarylamines were synthesized and investigated for internal charge transfer behavior. Using a large chromophore as one aryl group forced the triarylamines into twisted, propeller-like conformations. The chromophore anthracene was utilized to induce the twist in the triarylamines 9DAAA and 910BAA. The previously synthesized 9BrH was utilized to induce a twisted conformation for the triarylamine 9DAAH. Theoretical predictions indicated that electron density should be delocalized in the ground state and localized on the large chromophore in the excited state, behavior consistent with molecular internal charge transfer. 9DAAA and 910BAA were characterized by X-Ray crystallography which confirmed the desired twisted conformation of the triarylamines in the solid state. UV-Vis absorption spectra for all three triarylamines had long wavelength, broad absorption peaks characteristic of internal charge transfer. Solution fluorescence of each triarylamine demonstrated a large dependence on the surrounding environment; when solvent polarity was

  18. Protective antitumor immunity induced by tumor cell lysates conjugated with diphtheria toxin and adjuvant epitope in mouse breast tumor models

    Institute of Scientific and Technical Information of China (English)

    Ze-Yu Wang; Rong-Yue Cao; Jie Wu; Tai-Ming LI; Jing-Jing Liu; Yun Xing; Bin Liu; Lei Lu; Xiao Huang; Chi-Yu Ge; Wen-Jun Yao; Mao-Lei Xu; Zhen-Qiu Gao

    2012-01-01

    Cancer cell vaccine-based immunotherapy has received increasing interest in many clinical trials involving patients with breast cancer.Combining with appropriate adjuvants can enhance the weak immunogenic properties of tumor cell lysates (TCL).In this study,diphtheria toxin (DT) and two tandem repeats of mycobacterial heat shock protein 70 (mHSP70) fragment 407-426 (M2) were conjugated to TCL with glutaraldehyde,and the constructed cancer cell vaccine was named DT-TCL-M2.Subcutaneous injection of DT-TCL-M2 in mice effectively elicited tumor-specific polyclonal immune responses,including humoral and cellular immune responses.High levels of antibodies against TCL were detected in the serum of immunized mice with ELISA and verified with Western blot analyses.The splenocytes from immunized mice showed potent cytotoxicity on Ehrlich ascites carcinoma cells.Moreover,the protective antitumor immunity induced by DT-TCL-M2 inhibited tumor growth in a mouse breast tumor model.DTTCL-M2 also attenuated tumor-induced angiogenesis and slowed tumor growth in a mouse intradermal tumor model.These findings demonstrate that TCL conjugated with appropriate adjuvants induced effective antitumor immunity in vivo.Improvements in potency could further make cancer cell vaccines a useful and safe method for preventing cancer recurrence after resection.

  19. Gene delivery to brain cells with apoprotein E derived peptide conjugated to polylysine (apoEdp-PLL).

    Science.gov (United States)

    Mousazadeh, Mohammad; Palizban, Abbasali; Salehi, Rasool; Salehi, Mansoor

    2007-04-01

    A promising strategy to carry genetic material to brain cells either in vitro or in vivo is using the LDL receptor (LDLr) on blood-brain barrier. LDLr naturally help to low density lipoproteins (LDL(S)) transporting across the BBB by endocytosis. Here we present the idea of using the LDLr-mediated pathway for transporting genetic material to brain cells. A tandem dimer Sequence of apoprotein-E (apoE) (141-150) conjugated to polylysine sequence was used as a novel DNA Delivery vector for transfecting of brain cells either in vitro or in vivo. DNA condensation occurs with this vector because electrostatic interaction between DNA and polylysine. The vector favors to protection of DNA from enzymatic degradation and also helps to DNA carrying in blood stream to reach BBB and transport it to brain cells and eventually help DNA expression in target cells. These results suggest a novel gene delivery vector for gene therapy of brain disease.

  20. The Role of the Conjugate Bridge in Electronic Structures and Related Properties of Tetrahydroquinoline for Dye Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    You-Zhi Wu

    2013-03-01

    Full Text Available To understand the role of the conjugate bridge in modifying the properties of organic dye sensitizers in solar cells, the computations of the geometries and electronic structures for 10 kinds of tetrahydroquinoline dyes were performed using density functional theory (DFT, and the electronic absorption and fluorescence properties were investigated via time dependent DFT. The population analysis, molecular orbital energies, radiative lifetimes, exciton binding energies (EBE, and light harvesting efficiencies (LHE, as well as the free energy changes of electron injection ( and dye regeneration ( were also addressed. The correlation of charge populations and experimental open-circuit voltage (Voc indicates that more charges populated in acceptor groups correspond to larger Voc. The elongating of conjugate bridge by thiophene units generates the larger oscillator strength, higher LHE, larger absolute value of , and longer relative radiative lifetime, but it induces the decreasing of EBE and . So the extending of conjugate bridge with thiopene units in organic dye is an effective way to increase the harvest of solar light, and it is also favorable for electron injection due to their larger . While the inversely correlated relationship between EBE and LHE implies that the dyes with lower EBE produce more efficient light harvesting.

  1. Synthesis of Hexagonal ZnO-PQ7 Nano Disks Conjugated with Folic Acid to Image MCF - 7 Cancer Cells.

    Science.gov (United States)

    Sureshkumar, S; Jothimani, B; Sridhar, T M; Santhosh, Arul; Venkatachalapathy, B

    2017-01-01

    Surface modified ZnO nanomaterial is widely used in the field of bioimaging worldwide due to its optical properties, electronic characteristics and biocompatibility. Fluorescent enhanced, Polyquaternium-7(PQ7) capped, ZnO hexagonal nano disks (ZnO-PQ7) were synthesised by simple wet chemical method. The structural and optical properties of ZnO-PQ7 hexagonal nano disks were characterized using XRD, UV-Visible, Fluorescence, HRTEM, EDAX and FTIR studies. The size of synthesised ZnO-PQ7 were around 30-45 nm as confirmed by HRTEM studies. Fluorescence emission intensity increased with increase in PQ7 concentration. ZnO-PQ7 was further conjugated with folic acid (FA) to target human breast cancer cell line (MCF-7) via EDC/NHS coupling chemistry. Conjugation of folic acid with ZnO-PQ7 was confirmed by FTIR studies. The cell viability study using Methyl thiazolyltetrazolium(MTT) assay has demonstrated that the ZnO-PQ7 conjugated FA composites (ZnO-PQ7-FA) exhibit low toxicity towards MCF-7 up to a concentration of 125 μg/mL. Confocal laser scanning microscopic images confirmed the uptake of ZnO-PQ7-FA nanoparticles by MCF-7 cells. This study reveals ZnO-PQ7-FA nano disks as a potential imaging agent for detection of cancer cells. The synthesis route reported in this article is simple and easy to follow for the synthesis of ZnO-PQ7-FA in bulk quantities with high purity.

  2. Conjugation of a Ru(II) arene complex to neomycin or to guanidinoneomycin leads to compounds with differential cytotoxicities and accumulation between cancer and normal cells.

    Science.gov (United States)

    Grau-Campistany, Ariadna; Massaguer, Anna; Carrion-Salip, Dolors; Barragán, Flavia; Artigas, Gerard; López-Senín, Paula; Moreno, Virtudes; Marchán, Vicente

    2013-05-01

    A straightforward methodology for the synthesis of conjugates between a cytotoxic organometallic ruthenium(II) complex and amino- and guanidinoglycosides, as potential RNA-targeted anticancer compounds, is described. Under microwave irradiation, the imidazole ligand incorporated on the aminoglycoside moiety (neamine or neomycin) was found to replace one triphenylphosphine ligand from the ruthenium precursor [(η(6)-p-cym)RuCl(PPh3)2](+), allowing the assembly of the target conjugates. The guanidinylated analogue was easily prepared from the neomycin-ruthenium conjugate by reaction with N,N'-di-Boc-N″-triflylguanidine, a powerful guanidinylating reagent that was compatible with the integrity of the metal complex. All conjugates were purified by semipreparative high-performance liquid chromatography (HPLC) and characterized by electrospray ionization (ESI) and matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and NMR spectroscopy. The cytotoxicity of the compounds was tested in MCF-7 (breast) and DU-145 (prostate) human cancer cells, as well as in the normal HEK293 (Human Embryonic Kidney) cell line, revealing a dependence on the nature of the glycoside moiety and the type of cell (cancer or healthy). Indeed, the neomycin-ruthenium conjugate (2) displayed moderate antiproliferative activity in both cancer cell lines (IC50 ≈ 80 μM), whereas the neamine conjugate (4) was inactive (IC50 ≈ 200 μM). However, the guanidinylated analogue of the neomycin-ruthenium conjugate (3) required much lower concentrations than the parent conjugate for equal effect (IC50 = 7.17 μM in DU-145 and IC50 = 11.33 μM in MCF-7). Although the same ranking in antiproliferative activity was found in the nontumorigenic cell line (3 ≫ 2 > 4), IC50 values indicate that aminoglycoside-containing conjugates are about 2-fold more cytotoxic in normal cells (e.g., IC50 = 49.4 μM for 2) than in cancer cells, whereas an opposite tendency was found

  3. Enhanced cellular delivery of cell-penetrating peptide-peptide nucleic acid conjugates by photochemical internalization

    DEFF Research Database (Denmark)

    Shiraishi, Takehiko; Nielsen, Peter E

    2011-01-01

    (antisense activity) is still limited by endocytotic entrapment. We have shown that this low bioavailability can be greatly improved by combining CPP-PNA conjugate administration with a photochemical internalization technique using photosensitizers such as aluminum phthalocyanine (AlPcS(2a...

  4. Multifunctional conjugated polymers with main-chain donors and side-chain acceptors for dye sensitized solar cells (DSSCs) and organic photovoltaic cells (OPVs).

    Science.gov (United States)

    Chang, Dong Wook; Ko, Seo-Jin; Kim, Jin Young; Park, Su-Moon; Lee, Hyo Joong; Dai, Liming; Baek, Jong-Beom

    2011-11-15

    A novel multifunctional conjugated polymer (RCP-1) composed of an electron-donating backbone (carbazole) and an electron-accepting side chain (cyanoacetic acid) connected through conjugated vinylene and terthiophene has been synthesized and tested as a photosensitizer in two major molecule-based solar cells, namely dye sensitized solar cells (DSSCs) and organic photovoltaic cells (OPVs). Promising initial results on overall power conversion efficiencies of 4.11% and 1.04% are obtained from the basic structure of DSSCs and OPVs based on RCP-1, respectively. The well-defined donor (D)-acceptor (A) structure of RCP-1 has made it possible, for the first time, to reach over 4% of power conversion efficiency in DSSCs with an organic polymer sensitizer and good operation stability.

  5. Conjugation in "Escherichia coli"

    Science.gov (United States)

    Phornphisutthimas, Somkiat; Thamchaipenet, Arinthip; Panijpan, Bhinyo

    2007-01-01

    Bacterial conjugation is a genetic transfer that involves cell-to-cell between donor and recipient cells. With the current method used to teach students in genetic courses at the undergraduate level, the transconjugants are identified using bacterial physiology and/or antibiotic resistance. Using physiology, however, is difficult for both…

  6. Do the Defects Make It Work? Defect Engineering in Pi-Conjugated Polymers and Their Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.; Reese, M.; Kopidakis N.; Gregg, B. A.

    2008-05-01

    The charged defect density in common pi-conjugated polymers such as poly(3-hexylthiophene), P3HT, is around 1018 cm-3. Despite, or perhaps because of, this huge defect density, bulk heterojunction solar cells made from these polymers and a C60 derivative such as PCBM exhibit some of the highest efficiencies (~5%) yet obtained in solid state organic photovoltaic cells. We discuss defects in molecular organic semiconductors and in pi-conjugated polymers. These defects can be grouped in two categories, covalent and noncovalent. Somewhat analogous to treating amorphous silicon with hydrogen, we introduce chemical methods to modify the density and charge of the covalent defects in P3HT by treating it with electrophiles such as dimethyl sulfate and nucleophiles such as sodium methoxide. The effects of these treatments on the electrical and photovoltaic properties and stability of organic PV cells is discussed in terms of the change in the number and chemical properties of the defects. Finally, we address the question of whether the efficiency of OPV cells requires the presence of these defects which function as adventitious p-type dopants. Their presence relieves the resistance limitations usually encountered in cleaner organic semiconductors and can create built-in electric fields at junctions.

  7. Use of N-terminal modified poly(L-lysine)-antibody conjugate as a carrier for targeted gene delivery in mouse lung endothelial cells.

    Science.gov (United States)

    Trubetskoy, V S; Torchilin, V P; Kennel, S J; Huang, L

    1992-01-01

    A DNA targeted delivery and expression system has been designed based on an N-terminal modified poly(L-lysine) (NPLL)-antibody conjugate, which readily forms a complex with plasmid DNA. Monoclonal antibodies against the cell-surface thrombomodulin conjugated with NPLL were used for targeted delivery of foreign plasmid DNA to an antigen-expressing mouse lung endothelial cell line in vitro and to mouse lungs in vivo. In both cases significant amounts of DNA can be specifically bound to the target cells or tissues. Specific gene expression was observed in the treated mouse lung endothelial cells.

  8. Conjugated linoleic acids influence fatty acid metabolism in ovine ruminal epithelial cells.

    Science.gov (United States)

    Masur, F; Benesch, F; Pfannkuche, H; Fuhrmann, H; Gäbel, G

    2016-04-01

    Conjugated linoleic acids (CLA), particularly cis-9,trans-11 (c9t11) and trans-10,cis-12 (t10c12), are used as feed additives to adapt to constantly increasing demands on the performance of lactating cows. Under these feeding conditions, the rumen wall, and the rumen epithelial cells (REC) in particular, are directly exposed to high amounts of CLA. This study determined the effect of CLA on the fatty acid (FA) metabolism of REC and expression of genes known to be modulated by FA. Cultured REC were incubated with c9t11, t10c12, and the structurally similar FA linoleic acid (LA), oleic acid (OA), and trans-vaccenic acid (TVA) for 48 h at a concentration of 100 µM. Cellular FA levels were determined by gas chromatography. Messenger RNA expression levels of stearoyl-CoA desaturase (SCD) and monocarboxylate transporter (MCT) 1 and 4 were quantified by reverse transcription-quantitative PCR. Fatty acid evaluation revealed significant effects of CLA, LA, OA, and TVA on the amount of FA metabolites of β-oxidation and elongation and of metabolites related to desaturation by SCD. The observed changes in FA content point (among others) to the ability of REC to synthesize c9t11 from TVA endogenously. The mRNA expression levels of SCD identified a decrease after CLA, LA, OA, or TVA treatment. In line with the changes in mRNA expression, we found reduced amounts of C16:1n-7 cis-9 and C18:1n-9 cis-9, the main products of SCD. The expression of MCT1 mRNA increased after c9t11 and t10c12 treatment, and CLA c9t11 induced an upregulation of MCT4. Application of peroxisome proliferator-activated receptor (PPAR) α antagonist suggested that activation of PPARα is involved in the changes of MCT1, MCT4, and SCD mRNA expression induced by c9t11. Participation of PPARγ in the changes of MCT1 and SCD mRNA expression was shown by the application of the respective antagonist. The study demonstrates that exposure to CLA affects both FA metabolism and regulatory pathways within REC.

  9. Decitabine immunosensitizes human gliomas to NY-ESO-1 specific T lymphocyte targeting through the Fas/Fas Ligand pathway

    Science.gov (United States)

    2011-01-01

    Background The lack of effective treatments for gliomas makes them a significant health problem and highlights the need for the development of novel and innovative treatment approaches. Immunotherapy is an appealing strategy because of the potential ability for immune cells to traffic to and destroy infiltrating tumor cells. However, the absence of well-characterized, highly immunogenic tumor-rejection antigens (TRA) in gliomas has limited the implementation of targeted immune-based therapies. Methods We hypothesized that treatment with the demethylating agent, decitabine, would upregulate the expression of TRA on tumor cells, thereby facilitating enhanced surveillance by TRA-specific T cells. Results and Discussion Treatment of human glioma cells with decitabine increased the expression of NY-ESO-1 and other well characterized cancer testes antigens. The upregulation of NY-ESO-1 made these tumors susceptible to NY-ESO-1-specific T-cell recognition and lysis. Interestingly, decitabine treatment of T98 glioma cells also sensitized them to Fas-dependent apoptosis with an agonistic antibody, while a Fas blocking antibody could largely prevent the enhanced functional recognition by NY-ESO-1 specific T cells. Thus, decitabine treatment transformed a non-immunogenic glioma cell into an immunogenic target that was efficiently recognized by NY-ESO-1--specific T cells. Conclusions Such data supports the hypothesis that agents which alter epigenetic cellular processes may "immunosensitize" tumor cells to tumor-specific T cell-mediated lysis. PMID:22060015

  10. Decitabine immunosensitizes human gliomas to NY-ESO-1 specific T lymphocyte targeting through the Fas/Fas Ligand pathway

    Directory of Open Access Journals (Sweden)

    Konkankit Veerauo V

    2011-11-01

    Full Text Available Abstract Background The lack of effective treatments for gliomas makes them a significant health problem and highlights the need for the development of novel and innovative treatment approaches. Immunotherapy is an appealing strategy because of the potential ability for immune cells to traffic to and destroy infiltrating tumor cells. However, the absence of well-characterized, highly immunogenic tumor-rejection antigens (TRA in gliomas has limited the implementation of targeted immune-based therapies. Methods We hypothesized that treatment with the demethylating agent, decitabine, would upregulate the expression of TRA on tumor cells, thereby facilitating enhanced surveillance by TRA-specific T cells. Results and Discussion Treatment of human glioma cells with decitabine increased the expression of NY-ESO-1 and other well characterized cancer testes antigens. The upregulation of NY-ESO-1 made these tumors susceptible to NY-ESO-1-specific T-cell recognition and lysis. Interestingly, decitabine treatment of T98 glioma cells also sensitized them to Fas-dependent apoptosis with an agonistic antibody, while a Fas blocking antibody could largely prevent the enhanced functional recognition by NY-ESO-1 specific T cells. Thus, decitabine treatment transformed a non-immunogenic glioma cell into an immunogenic target that was efficiently recognized by NY-ESO-1--specific T cells. Conclusions Such data supports the hypothesis that agents which alter epigenetic cellular processes may "immunosensitize" tumor cells to tumor-specific T cell-mediated lysis.

  11. Gold nanoparticles generated and stabilized by water soluble curcumin-polymer conjugate: blood compatibility evaluation and targeted drug delivery onto cancer cells.

    Science.gov (United States)

    Manju, S; Sreenivasan, K

    2012-02-15

    Curcumin (Cur) shows low anticancer activity in vivo due to its reduced systemic bioavailability stemmed from its poor aqueous solubility and instability. Suitably functionalized nanocarriers designed to empty the drug specifically at tumor sites can potentially enhance the antitumor activity of Cur. We devised a simple method for the fabrication of water soluble Cur conjugated gold nanoparticles to target various cancer cell lines. Cur was conjugated to hyaluronic acid (HA) to get a water soluble conjugate (HA-Cur). We generated gold nanoparticles (AuNPs) by reducing chloroauric acid using HA-Cur, which played the dual role of a reducing and stabilizing agent and subsequently anchored folate conjugated PEG. These entities were probed using different analytical techniques, assayed the blood compatibility and cytotoxicity. Their interaction with cancer cell lines (HeLa cells, glyoma cells and Caco 2 cells) was followed by flow cytometry and confocal microscopy. Blood-materials interactions studies showed that the nanoparticles are highly hemocompatible. Flow cytometry and confocal microscopy results showed significant cellular uptake and internalization of the particles by cells. HA-Cur@AuNPs exhibited more cytotoxicity comparing to free Cur. The strategy, we adopted here, resulted the formation blood compatible Cur conjugated AuNPs with enhanced targeting and improved efficacy. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Chromatin structure determines accessibility of a hairpin polyamide-chlorambucil conjugate at histone H4 genes in pancreatic cancer cells.

    Science.gov (United States)

    Jespersen, Christine; Soragni, Elisabetta; James Chou, C; Arora, Paramjit S; Dervan, Peter B; Gottesfeld, Joel M

    2012-06-15

    We have shown that a specific pyrrole-imidazole polyamide-DNA alkylator (chlorambucil) conjugate, 1R-Chl, alters the growth characteristics of various cancer cell lines in culture, and causes these cells to arrest in the G2/M stage of the cell cycle, without apparent cytotoxicity. This molecule has also shown efficacy in several mouse xenograft models, preventing tumor growth. Previous microarray studies have suggested that members of the histone H4 gene family, H4c and H4j/k, are the primary targets of this molecule, leading to reduced histone mRNA synthesis and growth arrest in cancer cells. In the present study, we examine the effects of 1R-Chl on transcription of other members of the H4 gene family, with the result that mRNA transcription of most genomic copies of H4 are down-regulated by 1R-Chl in a human pancreatic cancer cell line (MIA PaCa-2), but not in a cell line of non-cancerous origin (HEK293 cells). The basis for this differential effect is likely an open chromatin conformation within the H4 genes in cancer cells. Chromatin immunoprecipitation experiments show increased histone acetylation on the histone H4 genes in cancer cells, compared to HEK293 cells, explaining the differential activity of this molecule in cancer versus non-cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. IL-6 Antibody and RGD Peptide Conjugated Poly(amidoamine) Dendrimer for Targeted Drug Delivery of HeLa Cells.

    Science.gov (United States)

    Mekuria, Shewaye Lakew; Debele, Tilahun Ayane; Chou, Hsiao-Ying; Tsai, Hsieh-Chih

    2016-01-14

    In this study, PAMAM dendrimer (G4.5) was conjugated with two targeting moieties, IL-6 antibody and RGD peptide (G4.5-IL6 and G4.5-RGD conjugates). Doxorubicin anticancer drug was physically loaded onto G4.5-IL6 and G4.5-RGD with the encapsulation efficiency of 51.3 and 30.1% respectively. The cellular internalization and uptake efficiency of G4.5-IL6/DOX and G4.5-RGD/DOX complexes was observed and compared by confocal microscopy and flow cytometry using HeLa cells, respectively. The lower IC50 value of G4.5-IL6/DOX in comparison to G4.5-RGD/DOX is indication that higher drug loading and faster drug release rate corresponded with greater cytotoxicity. The cytotoxic effect was further verified by increment in late apoptotic/necrotic cells due to delivery of drug through receptor-mediated endocytosis. On the basis of these results, G4.5-IL6 is a better suited carrier for targeted drug delivery of DOX to cervical cancer cells.

  14. Difluorobenzothiadiazole based two-dimensional conjugated polymers with triphenylamine substituted moieties as pendants for bulk heterojunction solar cells

    Directory of Open Access Journals (Sweden)

    W. H. Lee

    2017-11-01

    Full Text Available Three donor/acceptor (D/A-type two-dimensional polythiophenes (PTs; PBTFA13, PBTFA12, PBTFA11 featuring difluorobenzothiadiazole (DFBT derivatives as the conjugated (acceptor units in the polymer backbone and tertbutyl–substituted triphenylamine (tTPA-containing moieties as (donor pendants have been synthesized and characterized. These PTs exhibited good thermal stabilities, broad absorption spectra, and narrow optical band gaps. The cutoff wavelength of the UV–Vis absorption band was red-shifted upon increasing the content of the DFBT units in the PTs. Bulk heterojunction solar cells having an active layer comprising blends of the PTs and fullerene derivatives [6,6] phenyl-C61/71-butyric acid methyl ester (PC61BM/PC71BM were fabricated; their photovoltaic performance was strongly dependent on the content of the DFBT derivative in the PT. Incorporating a suitable content of the DFBT derivative in the polymer backbone enhanced the solar absorption ability and conjugation length of the PTs. The photovoltaic properties of the PBTFA13-based solar cells were superior to those of the PBTFA11- and PBTFA12-based solar cells.

  15. Quantitative analysis of agonist-dependent parathyroid hormone receptor trafficking in whole cells using a functional green fluorescent protein conjugate.

    Science.gov (United States)

    Conway, B R; Minor, L K; Xu, J Z; D'Andrea, M R; Ghosh, R N; Demarest, K T

    2001-12-01

    Many G-protein coupled receptors (GPCRs) undergo ligand-dependent internalization upon activation. The parathyroid hormone (PTH) receptor undergoes endocytosis following prolonged exposure to ligand although the ultimate fate of the receptor following internalization is largely unknown. To investigate compartmentalization of the PTH receptor, we have established a stable cell line expressing a PTH receptor-green fluorescent protein (PTHR-GFP) conjugate and an algorithm to quantify PTH receptor internalization. HEK 293 cells expressing the PTHR-GFP were compared with cells expressing the wild-type PTH receptor in whole-cell binding and functional assays. 125I-PTH binding studies revealed similar Bmax and kD values in cells expressing either the PTHR-GFP or the wild-type PTH receptor. PTH-induced cAMP accumulation was similar in both cell lines suggesting that addition of the GFP to the cytoplasmic tail of the PTH receptor does not alter the ligand binding or G-protein coupling properties of the receptor. Using confocal fluorescence microscopy, we demonstrated that PTH treatment of cells expressing the PTHR-GFP conjugate produced a time-dependent redistribution of the receptor to the endosomal compartment which was blocked by pretreatment with PTH antagonist peptides. Treatment with hypertonic sucrose prevented PTH-induced receptor internalization, suggesting that the PTH receptor internalizes via a clathrin-dependent mechanism. Moreover, co-localization with internalized transferrin showed that PTHR-GFP trafficking utilized the endocytic recycling compartment. Experiments using cycloheximide to inhibit protein synthesis demonstrated that recycling of the PTHR-GFP back to the plasma membrane was complete within 1-2 h of ligand removal and was partially blocked by pretreatment with cytochalasin D, but not nocodazole. We also demonstrated that the PTH receptor, upon recycling to the plasma membrane, is capable of undergoing a second round of internalization, a finding

  16. Modification of Akt by SUMO conjugation regulates alternative splicing and cell cycle

    OpenAIRE

    Risso, Guillermo; Pelisch, Federico; Pozzi, Berta; Mammi, Pablo; Blaustein, Matías; Colman-Lerner, Alejandro; Srebrow, Anabella

    2013-01-01

    Akt/PKB is a key signaling molecule in higher eukaryotes and a crucial protein kinase in human health and disease. Phosphorylation, acetylation, and ubiquitylation have been reported as important regulatory post-translational modifications of this kinase. We describe here that Akt is modified by SUMO conjugation, and show that lysine residues 276 and 301 are the major SUMO attachment sites within this protein. We found that phosphorylation and SUMOylation of Akt appear as independent events. ...

  17. Effect of polymer aggregation on the open circuit voltage in organic photovoltaic cells: aggregation-induced conjugated polymer gel and its application for preventing open circuit voltage drop.

    Science.gov (United States)

    Kim, Bong-Gi; Jeong, Eun Jeong; Park, Hui Joon; Bilby, David; Guo, L Jay; Kim, Jinsang

    2011-03-01

    To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV-vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.

  18. Cu(II) complexes of glyco-imino-aromatic conjugates in DNA binding, plasmid cleavage and cell cytotoxicity

    Indian Academy of Sciences (India)

    Amit Kumar; Atanu Mitra; Amrendra Kumar Ajay; Manoj Kumar Bhat; Chebrolu P Rao

    2012-11-01

    Binding of metal complexes of C2-glucosyl conjugates with DNA has been established by absorption and fluorescence studies. Conformational changes occurred in DNA upon binding have been studied by circular dichroism. All these studies are suggestive that the metal complexes bind to DNA through intercalation. Binding of di-nuclear copper complex 5 was found to be stronger when compared to the other complexes studied. Copper complexes were found to cleave the plasmid DNA in the absence of oxidizing or reducing agent, whereas, zinc complexes do not cleave. Metal complexes have shown toxicity to the HeLa and MCF-7 cell lines.Morphological studies, western blot and FACS analysis are suggestive of apoptotic cell death induced by the metal complexes. Di-nuclear copper complexes were found to be better as compared to the mononuclear ones in binding, plasmid cleavage and also in causing more cell death.

  19. Synthesis and properties of vitamin E analog-conjugated neomycin for delivery of RNAi drugs to liver cells.

    Science.gov (United States)

    Iwata, Rintaro; Nakayama, Futoshi; Hirochi, Sakie; Sato, Kazuki; Piao, Wenying; Nishina, Kazutaka; Yokota, Takanori; Wada, Takeshi

    2015-02-15

    RNA interference (RNAi) is a promising tool to regulate gene expression by external double stranded RNAs (dsRNAs) such as siRNAs. As an efficient method to deliver siRNAs to liver cells, we propose a novel strategy using vitamin E (VE)-conjugated neomycin derivatives. With the aim of delivering RNAi-based drugs to liver cells, several tripod-type and prodrug-type neomycin derivatives were synthesized, all of which were thermodynamically stabilized RNA duplexes. The prodrug-type derivative 7 and the tripod-type derivative 10 were delivered to liver cancer cells and successfully induced RNAi activity. These results indicated the potential use of natural aminoglycosides as carriers of RNAi drugs.

  20. Synthesis of a conjugated pyrrolopyridazinedione–benzodithiophene (PPD–BDT) copolymer and its application in organic and hybrid solar cells

    KAUST Repository

    Knall, Astrid-Caroline

    2017-03-30

    Herein, we describe the synthesis and characterization of a conjugated donor–acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD–BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC70BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD–BDT/CuInS2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.Graphical abstract

  1. Preparation of epidermal growth factor (EGF) conjugated iron oxide nanoparticles and their internalization into colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Creixell, Mar [Department of Chemical Engineering, University of Puerto Rico, Mayagueez Campus, P.O. Box 9000, Mayagueez, PR 00681 (Puerto Rico); Department of Electronics, Faculty of Physics, University of Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain); Herrera, Adriana P.; Ayala, Vanessa; Latorre-Esteves, Magda [Department of Chemical Engineering, University of Puerto Rico, Mayagueez Campus, P.O. Box 9000, Mayagueez, PR 00681 (Puerto Rico); Perez-Torres, Marianela [Department of Pharmaceutical Sciences, University of Puerto Rico-Medical Sciences Campus, PO Box 365067, San Juan, PR 00936 (Puerto Rico); Torres-Lugo, Madeline [Department of Chemical Engineering, University of Puerto Rico, Mayagueez Campus, P.O. Box 9000, Mayagueez, PR 00681 (Puerto Rico); Rinaldi, Carlos, E-mail: carlos.rinaldi@upr.ed [Department of Chemical Engineering, University of Puerto Rico, Mayagueez Campus, P.O. Box 9000, Mayagueez, PR 00681 (Puerto Rico)

    2010-08-15

    Epidermal growth factor (EGF) was conjugated with carboxymethyldextran (CMDx) coated iron oxide magnetic nanoparticles using carbodiimide chemistry to obtain magnetic nanoparticles that target the epidermal growth factor receptor (EGFR). Epidermal growth factor modified magnetic nanoparticles were colloidally stable when suspended in biological buffers such as PBS and cell culture media. Both targeted and non-targeted nanoparticles were incubated with CaCo-2 cancer cells, known to overexpress EGFR. Nanoparticle localization within the cell was visualized by confocal laser scanning microscopy and light microscopy using Prussian blue stain. Results showed that targeted magnetic nanoparticles were rapidly accumulated in both flask-shaped small vesicles and large circular endocytic structures. Internalization patterns suggest that both clathrin-dependent and clathrin-independent receptors mediated endocytosis mechanisms are responsible for nanoparticle internalization.

  2. Preparation of epidermal growth factor (EGF) conjugated iron oxide nanoparticles and their internalization into colon cancer cells

    Science.gov (United States)

    Creixell, Mar; Herrera, Adriana P.; Ayala, Vanessa; Latorre-Esteves, Magda; Pérez-Torres, Marianela; Torres-Lugo, Madeline; Rinaldi, Carlos

    2010-08-01

    Epidermal growth factor (EGF) was conjugated with carboxymethyldextran (CMDx) coated iron oxide magnetic nanoparticles using carbodiimide chemistry to obtain magnetic nanoparticles that target the epidermal growth factor receptor (EGFR). Epidermal growth factor modified magnetic nanoparticles were colloidally stable when suspended in biological buffers such as PBS and cell culture media. Both targeted and non-targeted nanoparticles were incubated with CaCo-2 cancer cells, known to overexpress EGFR. Nanoparticle localization within the cell was visualized by confocal laser scanning microscopy and light microscopy using Prussian blue stain. Results showed that targeted magnetic nanoparticles were rapidly accumulated in both flask-shaped small vesicles and large circular endocytic structures. Internalization patterns suggest that both clathrin-dependent and clathrin-independent receptors mediated endocytosis mechanisms are responsible for nanoparticle internalization.

  3. Nuclear estrogen receptor targeted photodynamic therapy: selective uptake and killing of MCF-7 breast cancer cells by a C17alpha-alkynylestradiol-porphyrin conjugate.

    Science.gov (United States)

    Swamy, Narasimha; Purohit, Ajay; Fernandez-Gacio, Ana; Jones, Graham B; Ray, Rahul

    2006-10-15

    We hypothesized that over-expression of estrogen receptor (ER) in hormone-sensitive breast cancer could be harnessed synergistically with the tumor-migrating effect of porphyrins to selectively deliver estrogen-porphyrin conjugates into breast tumor cells, and preferentially kill the tumor cells upon exposure to red light. In the present work we synthesized four (4) conjugates of C17-alpha-alkynylestradiol and chlorin e6-dimethyl ester with varying tether lengths, and showed that all these conjugates specifically bound to recombinant ER alpha. In a cellular uptake assay with ER-positive MCF-7 and ER-negative MDA-MB 231 human breast cancer cell-lines, we observed that one such conjugate (E17-POR, XIV) was selectively taken up in a dose-dependent and saturable manner by MCF-7 cells, but not by MDA-MB 231 cells. Furthermore, MCF-7 cells, but not MDA-MB 231 cells, were selectively and efficiently killed by exposure to red light after incubation with E17-POR. Therefore, the combination approach, including drug and process modalities has the potential to be applied clinically for hormone-sensitive cancers in organs where ER is significantly expressed. This could potentially be carried out either as monotherapy involving a photo-induced selective destruction of tumor cells and/or adjuvant therapy in post-surgical treatment for the destruction of residual cancer cells in tissues surrounding the tumor.

  4. Bone marrow cells stained by azide-conjugated Alexa fluors in the absence of an alkyne label.

    Science.gov (United States)

    Lin, Guiting; Ning, Hongxiu; Banie, Lia; Qiu, Xuefeng; Zhang, Haiyang; Lue, Tom F; Lin, Ching-Shwun

    2012-09-01

    Thymidine analog 5-ethynyl-2'-deoxyuridine (EdU) has recently been introduced as an alternative to 5-bromo-2-deoxyuridine (BrdU) for cell labeling and tracking. Incorporation of EdU into replicating DNA can be detected by azide-conjugated fluors (eg, Alexa-azide) through a Cu(i)-catalyzed click reaction between EdU's alkyne moiety and azide. While this cell labeling method has proven to be valuable for tracking transplanted stem cells in various tissues, we have found that some bone marrow cells could be stained by Alexa-azide in the absence of EdU label. In intact rat femoral bone marrow, ~3% of nucleated cells were false-positively stained, and in isolated bone marrow cells, ~13%. In contrast to true-positive stains, which localize in the nucleus, the false-positive stains were cytoplasmic. Furthermore, while true-positive staining requires Cu(i), false-positive staining does not. Reducing the click reaction time or reducing the Alexa-azide concentration failed to improve the distinction between true- and false-positive staining. Hematopoietic and mesenchymal stem cell markers CD34 and Stro-1 did not co-localize with the false-positively stained cells, and these cells' identity remains unknown.

  5. Synthesis and decay of calmodulin-ubiquitin conjugates in cell-free extracts of various rabbit tissues.

    Science.gov (United States)

    Laub, M; Jennissen, H P

    1997-06-27

    of 30 min was followed in liver crude extracts by the addition of EGTA, which specifically inhibits ubiquityl-calmodulin synthesis, a half-life of calmodulin-conjugate decay of 15-20 min is observed. A similar conjugate half-life of ca. 30 min was observed after addition of EDTA excluding that conjugate decay is due to an ATP-dependent proteolytic process. Studying the decay of purified ubiquitin-125I-BH-calmodulin conjugates in cell-free reticulocyte extracts led to the discovery of an ATP-independent isopeptidase activity which splits ubiquitin-calmodulin conjugates without leading to detectable calmodulin fragments. The rapid decay of ubiquitin-calmodulin conjugates in tissue extracts can therefore be plausibly explained by a ubiquityl-calmodulin splitting isopeptidase activity.

  6. The antiproliferative effects of biologically active isomers of conjugated linoleic acid on human colorectal and prostatic cancer cells.

    Science.gov (United States)

    Palombo, John D; Ganguly, Aniruddha; Bistrian, Bruce R; Menard, Michael P

    2002-03-28

    The antiproliferative effects of two commercial preparations of conjugated linoleic acid (CLA) and their constituent isomers, cis-9, trans-11 (c9,t11)-CLA, c9,c11-CLA, and t10,c12-CLA, were determined in vitro using human colorectal (HT-29, MIP-101) and prostate (PC-3) carcinoma cells adapted to serum-free medium. The antiproliferative effects of the preparations were dependent upon the type and concentration of CLA isomer present. The t10,c12-CLA isomer exhibited the greatest potency against colorectal cancer proliferation, and the c9,t11 and t10,c12 isomers were moderately effective against prostate cancer. The t10,c12 isomer induced caspase-dependent apoptosis in MIP-101 and PC-3 cells. The results are the first to demonstrate that physiologic levels of two CLA preparations, their constituent isomers, and the c9,t11-CLA elongation product, c11,t13-conjugated eicosadienoic acid, induce dose-dependent inhibitory effects on cancer proliferation in vitro. Novel CLA preparations may prove effective as chemopreventive supplements for individuals at risk of or diagnosed with colorectal or prostate cancer.

  7. E-selectin binding peptide-polymer-drug conjugates and their selective cytotoxicity against vascular endothelial cells.

    Science.gov (United States)

    Shamay, Yosi; Paulin, Denise; Ashkenasy, Gonen; David, Ayelet

    2009-11-01

    The hypothesis that E-selectin on activated endothelial cells could be exploited to selectively target drug delivery systems to tumor vasculature was investigated. HPMA copolymer-doxorubicin (DOX) conjugates displaying the high affinity E-selectin binding peptide (Esbp, primary sequence DITWDQLWDLMK) as targeting ligand were synthesized and tested for their cytotoxicity and intracellular fate in human immortalized vascular endothelial cells (IVECs). The targeted copolymers displaying multiple copies of Esbp are bound to surface-associated E-selectin with affinity at the low nano-molar range, three orders of magnitude stronger than the free Esbp. In addition, the binding affinity of the HPMA-Esbp copolymers to E-selectin expressing IVECs was found to be 10-fold superior relative to non-targeted copolymers. Once bound, E-selectin facilitated rapid internalization and lysosomal trafficking of the copolymers. This lysosomotropism of HPMA-Esbp-bound DOX copolymers was then correlated with a 150-fold higher cytotoxicity relative to non-targeted HPMA-DOX conjugates. These findings strongly support the emerging role of E-selectin as a viable target for controlled drug delivery in cancer therapy.

  8. The effect of trans-10, cis-12 conjugated linoleic acid on gene expression profiles related to lipid metabolism in human intestinal-like Caco-2 cells

    NARCIS (Netherlands)

    Murphy, E.F.; Hooiveld, G.J.E.J.; Müller, M.R.; Calogero, R.A.; Cashman, K.D.

    2009-01-01

    We conducted an in-depth investigation of the effects of conjugated linoleic acid (CLA) on the expression of key metabolic genes and genes of known importance in intestinal lipid metabolism using the Caco-2 cell model. Cells were treated with 80 mu mol/L of linoleic acid (control), trans-10, cis-12

  9. Synthesis and characterization of Her2-NLP peptide conjugates targeting circulating breast cancer cells: cellular uptake and localization by fluorescent microscopic imaging.

    Science.gov (United States)

    Cai, Huawei; Singh, Ajay N; Sun, Xiankai; Peng, Fangyu

    2015-01-01

    To synthesize a fluorescent Her2-NLP peptide conjugate consisting of Her2/neu targeting peptide and nuclear localization sequence peptide (NLP) and assess its cellular uptake and intracellular localization for radionuclide cancer therapy targeting Her2/neu-positive circulating breast cancer cells (CBCC). Fluorescent Cy5.5 Her2-NLP peptide conjugate was synthesized by coupling a bivalent peptide sequence, which consisted of a Her2-binding peptide (NH2-GSGKCCYSL) and an NLP peptide (CGYGPKKKRKVGG) linked by a polyethylene glycol (PEG) chain with 6 repeating units, with an activated Cy5.5 ester. The conjugate was separated and purified by HPLC and then characterized by Maldi-MS. The intracellular localization of fluorescent Cy5.5 Her2-NLP peptide conjugate was assessed by fluorescent microscopic imaging using a confocal microscope after incubation of Cy5.5-Her2-NLP with Her2/neu positive breast cancer cells and Her2/neu negative control breast cancer cells, respectively. Fluorescent signals were detected in cytoplasm of Her2/neu positive breast cancer cells (SKBR-3 and BT474 cell lines), but not or little in cytoplasm of Her2/neu negative breast cancer cells (MDA-MB-231), after incubation of the breast cancer cells with Cy5.5-Her2-NLP conjugates in vitro. No fluorescent signals were detected within the nuclei of Her2/neu positive SKBR-3 and BT474 breast cancer cells, neither Her2/neu negative MDA-MB-231 cells, incubated with the Cy5.5-Her2-NLP peptide conjugates, suggesting poor nuclear localization of the Cy5.5-Her2-NLP conjugates localized within the cytoplasm after their cellular uptake and internalization by the Her2/neu positive breast cancer cells. Her2-binding peptide (KCCYSL) is a promising agent for radionuclide therapy of Her2/neu positive breast cancer using a β(-) or α emitting radionuclide, but poor nuclear localization of the Her2-NLP peptide conjugates may limit its use for eradication of Her2/neu-positive CBCC using I-125 or other Auger electron

  10. Specific Intracellular Uptake of Herceptin-Conjugated CdSe/ZnS Quantum Dots into Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Seung-Jin Han

    2014-01-01

    Full Text Available Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs to enhance their specific interactions with breast cancer cells (SK-BR3. The mean size of the core-shell quantum dots (28 nm, as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. The in vitro cell culture experiment showed that the keratin forming cancer cells (KB proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL, whereas most of the breast cancer cells (SK-BR3 had died. To clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined by confocal laser scanning microscopy. As a result, the QD-Her bound specifically to the membrane of SK-BR3, which became almost saturated after 6 hours incubation. This suggests that the growth signal of breast cancer cells is inhibited completely by the specific binding of herceptin to the Her-2 receptor of SK-BR3 membrane, resulting in cell death.

  11. Influencing Selectivity to Cancer Cells with Mixed Nanoparticles Prepared from Albumin-Polymer Conjugates and Block Copolymers.

    Science.gov (United States)

    Jiang, Yanyan; Wong, Sandy; Chen, Fan; Chang, Ted; Lu, Hongxu; Stenzel, Martina H

    2017-04-19

    Albumin-based nanoparticles are widely used to delivery anticancer drug because they promote the accumulation of drugs in tumor sites. Nanoparticles with surface immobilized albumin are widely described in literature, although mixed nanoparticles with systematically modified ratios between albumin and PEG-based material are less common. In this work, hybrid nanoparticles were prepared by coassembly of a PEG-based amphiphilic block copolymer together with a polymer-protein conjugate. Poly(oligo(ethylene glycol) methyl ether acrylate)-poly(ε-caprolactone) (POEGMEA-PCL) was prepared by a combination of ring-opening polymerization and reversible addition-fragmentation chain transfer (RAFT) polymerization, while the polymer-protein conjugate was obtained by reacting poly(ε-caprolactone) with bovine serum albumin (BSA-PCL). Co-assembly of both amphiphiles at different ratios, with and without curcumin as a drug, led to hybrid nanoparticles with various amount of albumin on the particle surface. The resulting hybrid nanoparticles were similar in size (100-120 nm), but increasing the amount of albumin on the surface led to a more-negative ζ potential. The cytotoxicity of the curcumin-loaded nanoparticles was examined on several cell lines. The curcumin-loaded nanoparticles with high amount of albumin led to high cytotoxicity against breast cancer cell lines (MDA-MB-231 and MCF-7), which coincided with high cellular uptake. However, the cytotoxicity of the curcumin-loaded nanoparticles against CHO cells and RAW264.7 cells was reduced, suggesting that albumin can facilitate selectivity toward cancer cells.

  12. Supramolecular assemblies of a conjugate of nucleobase, amino acids, and saccharide act as agonists for proliferation of embryonic stem cells and development of zygotes.

    Science.gov (United States)

    Du, Xuewen; Zhou, Jie; Guvench, Olgun; Sangiorgi, Frank O; Li, Xinming; Zhou, Ning; Xu, Bing

    2014-06-18

    The synthetic challenges in glycobiology and glycochemistry hamper the development of glycobiomaterials for biomedicine. Here we report the use of molecular self-assembly to sidestep the laborious synthesis of complex glycans for promoting the proliferation of murine embryonic stem (mES) cells. Our study shows that the supramolecular assemblies of a small molecule conjugate of nucleobase, amino acids, and saccharide, as a de novo glycoconjugate, promote the proliferation of mES cells and the development of zygotes into blastocysts of mouse. Molecular engineering confirms that each motif (i.e., adenine, Arg-Gly-Asp (RGD) domain, and glucosamine) is indispensable for the observed activity of the conjugate. As the first example of using assemblies of the molecular conjugates of multiple fundamental biological building blocks to control cell behaviors, this work illustrates an unprecedented approach to use supramolecular assemblies as multifunctional mimics of glycoconjugates.

  13. Phototodynamic activity of zinc monocarboxyphenoxy phthalocyane (ZnMCPPc) conjugated to gold silver (AuAg) nanoparticles in melanoma cancer cells

    Science.gov (United States)

    Manoto, Sello L.; Oluwole, David O.; Malabi, Rudzani; Maphanga, Charles; Ombinda-Lemboumba, Saturnin; Nyokong, Tebello; Mthunzi-Kufa, Patience

    2017-02-01

    Photodynamic therapy (PDT) is a minimally invasive therapeutic modality for the treatment of neoplastic and non-neoplastic diseases. In PDT of cancer, irradiation with light of a specific wavelength leads to activation of a photosensitizer which results in generation of reactive oxygen species (ROS) which induces cell death. Many phthalocyanine photosensitizers are hydrophobic and insoluble in water, which limits their therapeutic efficiency. Consequently, advanced delivery systems and strategies are needed to improve the effectiveness of these photosensitizers. Nanoparticles have shown promising results in increasing aqueous solubility, bioavailability, stability and delivery of photosensitizers to their target. This study investigated the photodynamic activity of zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc) conjugated to gold silver (AuAg) nanoparticles in melanoma cancer cells. The photodynamic activity of ZnMCPPc conjugated to AuAg nanoparticles were evaluated using cellular morphology, viability, proliferation and cytotoxicity. Untreated cells showed no changes in cellular morphology, proliferation and cytotoxicity. However, photoactivated ZnMCPPc conjugated to AuAg nanoparticles showed changes in cell morphology and a dose dependent decrease in cellular viability, proliferation and an increase in cell membrane damage. The ZnMCPPc conjugated to AuAg nanoparticles used in this study was highly effective in inducing cell death of melanoma cancer cells.

  14. Arginine–glycine–aspartic acid–polyethylene glycol–polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture

    Directory of Open Access Journals (Sweden)

    Chen Z

    2016-08-01

    Full Text Available Zhanfei Chen,1,* Fen Lian,1,* Xiaoqian Wang,1 Yanling Chen,1,2 Nanhong Tang1,2 1Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, 2Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The polyamidoamine (PAMAM dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine–glycine–aspartic acid (RGD peptide. Our studies demonstrate that RGD–polyethylene glycol (PEG–PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT–MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. Keywords: dendrimer, arginine–glycine–aspartic acid (RGD, liver cell, spheroid culture, ammonia metabolism

  15. In vitro detection of human breast cancer cells (SK-BR3) using herceptin-conjugated liquid crystal microdroplets as a sensing platform.

    Science.gov (United States)

    Ding, Wang; Gupta, Kailash Chandra; Park, Soo-Young; Kim, Young-Kyoo; Kang, Inn-Kyu

    2016-10-20

    The present study utilizes antibody-protein interactions to develop an LC microdroplet based biosensor for naked eye detection of SK-BR3 human breast cancer cells. The herceptin antibody-conjugated LC microdroplets were fabricated using 4-cyano-4'-pentyl biphenyl (5CB) as the liquid crystalline phase and sodium dodecyl sulfate (SDS) as the surfactant. The poly (styrene-b-acrylic acid) amphiphilic block copolymer (PS-b-PA) played a role as a modifier for the liquid crystalline interfaces. The 5CB molecules in the herceptin antibody-conjugated LC microdroplets have shown an orientation transition from radial to bipolar on selective interactions with targeted SK-BR3 breast cancer cells, which are over expressed by the human epidermal growth factor receptor 2-positive (HER2). The herceptin antibody-conjugated LC microdroplets are found to be highly selective in the detection of SK-BR3 cancer cells in the presence of control cells, such as KB cancer cells and fibroblast (FB), and also in the presence of 10% human blood plasma. The interaction forces of the SK-BR3 cancer cells were only effective in causing orientation transitions in 5CB molecules in the LC microdroplets, which clearly suggested that the herceptin antibody-conjugated LC microdroplets could be used as a selective biosensor for a real-time detection of SK-BR3 cancer cells in biological fluids.

  16. Quinoxaline-based π-conjugated donor polymer for highly efficient organic thin-film solar cells

    Science.gov (United States)

    Kitazawa, Daisuke; Watanabe, Nobuhiro; Yamamoto, Shuhei; Tsukamoto, Jun

    2009-08-01

    A quinoxaline-based π-conjugated donor polymer, poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(5',8'-di-2-thienyl-2',3'-diphenylquinoxaline)] (N-P7), was synthesized to achieve a high power conversion efficiency (PCE) of bulk heterojunction (BHJ)-based solar cells. The optical band-gap and highest occupied molecular orbital level of N-P7 were 1.95 and -5.37 eV, respectively. BHJ-based solar cells using N-P7 as a donor and phenyl C71 butyric acid methyl ester as an acceptor gave a PCE as high as 5.5% under AM 1.5G 100 mW/cm2 illumination. We also investigated the effects of substituent groups of quinoxaline-based polymers on the morphology of the BHJ layer.

  17. The efficient elimination of solid tumor cells by EGFR-specific and HER2-specific scFv-SNAP fusion proteins conjugated to benzylguanine-modified auristatin F.

    Science.gov (United States)

    Woitok, Mira; Klose, Diana; Niesen, Judith; Richter, Wolfgang; Abbas, Muhammad; Stein, Christoph; Fendel, Rolf; Bialon, Magdalena; Püttmann, Christiane; Fischer, Rainer; Barth, Stefan; Kolberg, Katharina

    2016-10-28

    Antibody-drug conjugates (ADCs) combine the potency of cytotoxic drugs with the specificity of monoclonal antibodies (mAbs). Most ADCs are currently generated by the nonspecific conjugation of drug-linker reagents to certain amino acid residues in mAbs, resulting in a heterogeneous product. To overcome this limitation and prepare ADCs with a defined stoichiometry, we use SNAP-tag technology as an alternative conjugation strategy. This allows the site-specific conjugation of O(6)-benzylguanine (BG)-modified small molecules to SNAP-tag fusion proteins. To demonstrate the suitability of this system for the preparation of novel recombinant ADCs, here we conjugated SNAP-tagged single chain antibody fragments (scFvs) to a BG-modified version of auristatin F (AURIF). We used two scFv-SNAP fusion proteins targeting members of the epidermal growth factor receptor (EGFR) family that are frequently overexpressed in breast cancer. The conjugation of BG-AURIF to EGFR-specific 425(scFv)-SNAP and HER2-specific αHER2(scFv)-SNAP resulted in two potent recombinant ADCs that specifically killed breast cancer cell lines by inducing apoptosis when applied at nanomolar concentrations. These data confirm that SNAP-tag technology is a promising tool for the generation of novel recombinant ADCs.

  18. Synthesis of ZnO nanoparticles using the cell extract of the cyanobacterium, Anabaena strain L31 and its conjugation with UV-B absorbing compound shinorine.

    Science.gov (United States)

    Singh, Garvita; Babele, Piyoosh K; Kumar, Ashok; Srivastava, Anup; Sinha, Rajeshwar P; Tyagi, Madhu B

    2014-09-01

    In the present work, we describe a cheap, unexplored and simple procedure for the synthesis of zinc oxide nanoparticles (ZnONPs) using the cell extract of the cyanobacterium, Anabaena strain L31. An attempt was also made to conjugate synthesized ZnONPs with a UV-absorbing water soluble compound shinorine. UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, transmission electron microscopy (TEM) and TEM-selected area electron diffraction (SAED) analyses were made to elucidate the formation and characterization of ZnONPs and ZnONPs-shinorine conjugate. The synthesized ZnONPs were characterized by a sharp peak at 370 nm in UV-vis spectrum. TEM images showed the formation of spherical shaped nanoparticles with an average size of 80 nm. Results of selective area electron diffraction (SAED) pattern showed a set of rings which suggested uniform shape with hexagonal structure of ZnONPs. XRD spectra confirmed the crystalline structure of particles. Conjugation of ZnONPs with shinorine was successfully achieved at pH 7.0 and 10mM concentration of shinorine. The conjugate showed a zeta potential value of -3.75 mV as compared to +30.25 mV of ZnONPs. The change in zeta potential value of ZnONPs-shinorine conjugate was attributed to the changes in the surface functionalities after conjugation. The generation of in vivo reactive oxygen species (ROS) by Anabaena strain L31 with treatment of ZnONPs-shinorine conjugate showed approximately 75% less ROS generation as compared to ZnONPs. Properties exhibited by the ZnONPs-shinorine conjugate suggest that it may be used as a potential agent in developing environmental-friendly sunscreen filters of biological origin.

  19. Cationic liposomes enhance targeted delivery and expression of exogenous DNA mediated by N-terminal modified poly(L-lysine)-antibody conjugate in mouse lung endothelial cells.

    Science.gov (United States)

    Trubetskoy, V S; Torchilin, V P; Kennel, S; Huang, L

    1992-07-15

    A new and improved system for targeted gene delivery and expression is described. Transfection efficiency of N-terminal modified poly(L-lysine) (NPLL) conjugated with anti-thrombomodulin antibody 34A can be improved by adding to the system a lipophilic component, cationic liposomes. DNA, antibody conjugate and cationic liposomes form a ternary electrostatic complex which preserves the ability to bind specifically to the target cells. At the same time the addition of liposomes enhance the specific transfection efficiency of antibody-polylysine/DNA binary complex by 10 to 20-fold in mouse lung endothelial cells in culture.

  20. A bifunctional poly(ethylene glycol) silane immobilized on metallic oxide-based nanoparticles for conjugation with cell targeting agents

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Nathan J.; Fryxell, Glen E.; Zhang, Miqin

    2004-06-16

    A trifluoroethylester-terminal poly (ethylene glycol) (PEG) silane was synthesized and self-assembled on iron oxide nanoparticles. The nanoparticle system thus prepared has the flexibility to conjugate with cell targeting agents having either carboxylic and amine terminal groups for a number of biomedical applications, including magnetic resonance imaging (MRI) and controlled drug delivery. The trifluoroethylester silane was synthesized by modifying a PEG diacid to form the corresponding bistrifluoroethylester (TFEE), followed by a reaction with 3-aminopropyltriethoxysilane (APS). The APS coupled with PEG chains confers the stability of PEG self-assembled monolayers (SAMs) and increases the PEG packing density on nanoparticles by establishing hydrogen bonding between the carbonyl and amine groups present within the monolayer structure. The success of the synthesis of the PEG TEFE silane was confirmed with 1H NMR and Fourier transform infrared spectroscopy (FTIR). The conjugating flexibility of the PEG TEFE was demonstrated with folic acid having carboxylic acid groups and amine terminal groups respectively and confirmed by FTIR. TEM analysis showed the dispersion of nanoparticles before and after they were coated with PEG and folic acid.

  1. Preparation of HIV monoclonal antibody-conjugated pulchellin in order to study its intracellular trafficking pathway in HIV-infected cells by confocal microscopy

    Science.gov (United States)

    Sadraeian, M.; Tsutae, F. M.; Moreira, H. H. T.; Araujo, A. P. U.; Guimarães, F. E. G.; Pincus, S. H.

    2015-06-01

    Pulchellin is a type 2 of ribosome-inactivating proteins isolated from some seeds significantly growing in Brazil. It is a potent agent to inhibit the protein synthesis in cancer cells and also HIV-infected cells. Pulchellin can be conjugated to HIV monoclonal antibodies to specifically target the HIV-infected cells. To analyze the protein synthesis inhibition by Pulchellin, the intracellular localization of the immunoconjugate should be compared to Pulchellin. In this case, the intracellular trafficking of this protein in cells can be determined by confocal microscopy. In our study, we utilized Pulchellin to construct HIV monoclonal antibody-conjugated Pulchellin A chain in order to target HIV-infected lymphocyte cells. Afterward the conjugation was labeled with the superior Alexa Fluor 488 dye. As a subsequent step, we are interested in studying the intracellular trafficking pathway of this novel conjugation in HIV-infected cells by confocal microscopy. Moreover, possible quantitative methods for fluorescent labeling of the immunoconjugate during confocal microscopy will be investigated.

  2. The targeted transduction of MMP-overexpressing tumor cells by ACPP-HPMA copolymer-coated adenovirus conjugates.

    Directory of Open Access Journals (Sweden)

    Shuhua Li

    Full Text Available We have designed and tested a new way to selectively deliver HPMA polymer-coated adenovirus type 5 (Ad5 particles into matrix metalloproteinase (MMP-overexpressing tumor cells. An activatable cell penetrating peptide (ACPP was designed and attached to the reactive 4-nitrophenoxy groups of HPMA polymers by the C-terminal amino acid (asparagine, N. ACPPs are activatable cell penetrating peptides (CPPs with a linker between polycationic and polyanionic domains, and MMP-mediated cleavage releases the CPP portion and its attached cargo to enable cell entry. Our data indicate that the transport of these HPMA polymer conjugates by a single ACPP molecule to the cytoplasm occurs via a nonendocytotic and concentration-independent process. The uptake was observed to finish within 20 minutes by inverted fluorescence microscopy. In contrast, HPMA polymer-coated Ad5 without ACPPs was internalized solely by endocytosis. The optimal formulation was not affected by the presence of Ad5 neutralizing antibodies during transduction, and ACPP/polymer-coated Ad5 also retained high targeting capability to several MMP-overexpressing tumor cell types. For the first time, ACPP-mediated cytoplasmic delivery of polymer-bound Ad5 to MMP-overexpressing tumor cells was demonstrated. These findings are significant, as they demonstrate the use of a polymer-based system for the targeted delivery into MMP-overexpressing solid tumors and highlight how to overcome major cellular obstacles to achieve intracellular macromolecular delivery.

  3. Development of a novel microbubble-liposome complex conjugated with peptide ligands targeting IL4R on brain tumor cells.

    Science.gov (United States)

    Park, See-Hyoung; Yoon, Young Ii; Moon, Hyoungwon; Lee, Ga-Hyun; Lee, Byung-Heon; Yoon, Tae-Jong; Lee, Hak Jong

    2016-07-01

    Gas (SF6)-filled microbubbles (MBs) were prepared by emulsion and solvent-evaporation method. The prepared MBs were further conjugated with doxorubicin (Dox)-loaded nano-sized liposome and peptide ligands to interleukin-4 receptor (IL4R) for targeting brain tumor cells. The final MB-liposome (Dox)-IL4R targeting peptide ligand [MB-Lipo (Dox)-IL4RTP] had a spherical structure with the mean size of 1,500 nm. The MB-Lipo (Dox)‑IL4RTP exhibited cellular uptake in U87MG brain tumor cells (a brain tumor cell line expressing strongly IL4R) with frequency ultrasound energy suggesting that MB-Lipo (Dox)‑IL4RTP provided effective targeting ability for brain tumor cells. In addition, WST-1 assay results showed that MB-Lipo (Dox)‑IL4RTP inhibited the proliferation of U87MG cells IL4R‑dependently. This was confirmed by western blotting of γH2AX, phospho (Ser15)-p53, p53 and p21 which are signal transduction proteins involved in DNA damage response and cell cycle arrest. Taken together, these results indicate that MB-Lipo (Dox)-IL4RTP represents a promising ultrasonic contrast agent for tumor-targeting ultrasonic imaging.

  4. Low-toxic Mn-doped ZnSe@ZnS quantum dots conjugated with nano-hydroxyapatite for cell imaging

    Science.gov (United States)

    Zhou, Ronghui; Li, Mei; Wang, Shanling; Wu, Peng; Wu, Lan; Hou, Xiandeng

    2014-11-01

    Fluorescent bio-imaging has received significant attention in a myriad of research disciplines, and QDs are playing an increasingly important role in these areas. Doped QDs, an important alternative to conventional heavy metal-containing QDs are employed for biomedical applications. However, since QDs are exogenous substances to the biological environment, the biocompatibility of QDs is expected to be challenging in some cases. Herein, nano fluorine-doped hydroxyapatite (FAp, a well-known biocompatible material) was introduced to endow biocompatibility to Cd-free Mn-doped ZnSe@ZnS QDs. Thus, a nano-FAp-QD conjugate was developed and the biocompatibility, as well as potential cell imaging application, was investigated. To construct the proposed conjugate, Cd-free highly luminescent Mn-doped ZnSe@ZnS QDs and monodispersed nano-FAp were first prepared in high-temperature organic media. For facilitating the conjugation, hydrophobic nano-FAp was made water soluble via o-phosphoethanolamine (PEA) coating, which further provides conjugating sites for QDs to anchor. Cytotoxicity studies indicated the developed conjugate indeed possesses good compatibility and low toxicity to cells. The nano-FAp-QDs conjugate was successfully employed for cancer cell staining for at least 24 h, demonstrating the potential usefulness of this material in future biomedical research.Fluorescent bio-imaging has received significant attention in a myriad of research disciplines, and QDs are playing an increasingly important role in these areas. Doped QDs, an important alternative to conventional heavy metal-containing QDs are employed for biomedical applications. However, since QDs are exogenous substances to the biological environment, the biocompatibility of QDs is expected to be challenging in some cases. Herein, nano fluorine-doped hydroxyapatite (FAp, a well-known biocompatible material) was introduced to endow biocompatibility to Cd-free Mn-doped ZnSe@ZnS QDs. Thus, a nano-FAp-QD conjugate

  5. A Novel Thiophene Derivative-based Conjugated Polymer for Polymer Solar Cells with High Open-circuit Voltage

    Institute of Scientific and Technical Information of China (English)

    谌烈; 沈星星; 陈义旺

    2012-01-01

    A novel D-A alternative conjugated polymer PBDTDMCT containing benzo[1,2-b:4,5-b']dithiophene (BDT) and dimethyl thiophene-3,4-dicarboxylate (DMCT), was designed and synthesized by Stille cross-coupling reaction. The copolymer exhibited excellent solubility and good thermal stability. The optical band gap determined from the onset of absorption of the polymer film was 2.10 eV. By incorporation of the ester groups into the polymer side chain, the HOMO level of polymer PBDTDMT was tuned to be deep-lying (--5.65 eV). Open-circuit voltage of polymer solar cells constructed based on PBDTDMT and [6,6]-phenyl-CTwbutyric acid methyl ester (PCTIBM) can be tuned to achieve values as high as ca. 1.0 V.

  6. Comparison of selenophene and thienothiophene incorporation into pentacyclic lactam-based conjugated polymers for organic solar cells

    KAUST Repository

    Kroon, Renee

    2015-09-08

    In this work, we compare the effect of incorporating selenophene versus thienothiophene spacers into pentacyclic lactam-based conjugated polymers for organic solar cells. The two cyclic lactam-based copolymers were obtained via a new synthetic method for the lactam moiety. Selenophene incorporation results in a broader and red-shifted optical absorption while retaining a deep highest occupied molecular orbital level, whereas thienothienophene incorporation results in a blue-shifted optical absorption. Additionally, grazing-incidence wide angle X-ray scattering data indicates edge- and face-on solid state order for the selenophene-based polymer as compared to the thienothiophene-based polymer, which orders predominantly edge-on with respect to the substrate. In polymer:PCBM bulk heterojunction solar cells both materials show a similar open-circuit voltage of ∼0.80-0.84 V, however the selenophene-based polymer displays a higher fill factor of ∼0.70 vs. ∼0.65. This is due to the partial face-on backbone orientation of the selenophene-based polymer, leading to a higher hole mobility, as confirmed by single-carrier diode measurements, and a concomitantly higher fill factor. Combined with improved spectral coverage of the selenophene-based polymer, as confirmed by quantum efficiency experiments, it offers a larger short-circuit current density of ∼12 mA cm. Despite the relatively low molecular weight of both materials, a very robust power conversion efficiency ∼7% is achieved for the selenophene-based polymer, while the thienothiophene-based polymer demonstrates only a moderate maximum PCE of ∼5.5%. Hence, the favorable effects of selenophene incorporation on the photovoltaic performance of pentacyclic lactam-based conjugated polymers are clearly demonstrated.

  7. Photochemical stability of conjugated polymers, electron acceptors and blends for polymer solar cells resolved in terms of film thickness and absorbance

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Vesterager Madsen, Morten; Carlé, Jon Eggert

    2012-01-01

    acceptors poses a challenge to solar cell encapsulation if these materials are to be of commercial interest. The presented method is generally applicable to all types of organic materials to assess photochemical stabilities. The presented results of conjugated polymers demonstrate that this is a powerful...

  8. Antibody-antigen-adjuvant conjugates enable co-delivery of antigen and adjuvant to dendritic cells in cis but only have partial targeting specificity

    NARCIS (Netherlands)

    Kreutz, M.; Giquel, B.; Hu, Q.; Abuknesha, R.; Uematsu, S.; Akira, S.; Nestle, F.O.; Diebold, S.S.

    2012-01-01

    Antibody-antigen conjugates, which promote antigen-presentation by dendritic cells (DC) by means of targeted delivery of antigen to particular DC subsets, represent a powerful vaccination approach. To ensure immunity rather than tolerance induction the co-administration of a suitable adjuvant is par

  9. Thiophene in Conducting Polymers: Synthesis of Poly(thiophene)s and Other Conjugated Polymers Containing Thiophenes, for Application in Polymer Solar Cells

    DEFF Research Database (Denmark)

    Livi, Francesco; Carlé, Jon Eggert; Bundgaard, Eva

    2015-01-01

    Conducting polymers based on thiophene are described. The polymers include poly(thiophene) with and without side-chains and other conjugated polymers in general, based on thiophene. The synthesis and characteristics of the polymers are described along with the application of these as light......-absorbing materials in polymer solar cells....

  10. Toward High-Performance Organic-Inorganic Hybrid Solar Cells: Bringing Conjugated Polymers and Inorganic Nanocrystals in Close Contact.

    Science.gov (United States)

    He, Ming; Qiu, Feng; Lin, Zhiqun

    2013-06-06

    Organic-inorganic hybrid solar cells composed of conjugated polymers (CPs) and inorganic nanocrystal (NC) semiconductors have garnered considerable attention as a potential alternative to traditional silicon solar cells due to the capacity of producing high-efficiency solar energy in a cost-effective manner. The combination of advantageous characteristics of CPs and NCs enables the construction of nanostructured high-performance, lightweight, flexible, large-area, and low-cost hybrid solar cells. However, it remains a grand challenge to control the film morphology and interfacial structure of such organic/inorganic semiconductor blends on the nanoscale. In this Perspective, we highlight the strategies of implementing close contact between CPs and NCs by tailoring the colloidal synthesis, the coordination reaction, and the chemical modification of CPs. As such, they offer promising opportunities for rationally controlling the phase separation between electron-donating CPs and electron-accepting NCs, increasing the interfacial areas between them, enhancing their electronic interaction, and thus substantially promoting the photovoltaic performance of the resulting organic-inorganic hybrid solar cells.

  11. Altered membrane dynamics of quantum dot-conjugated integrins during osteogenic differentiation of human bone marrow derived progenitor cells.

    Science.gov (United States)

    Chen, Hongfeng; Titushkin, Igor; Stroscio, Michael; Cho, Michael

    2007-02-15

    Functionalized quantum dots offer several advantages for tracking the motion of individual molecules on the cell surface, including selective binding, precise optical identification of cell surface molecules, and detailed examination of the molecular motion without photobleaching. We have used quantum dots conjugated with integrin antibodies and performed studies to quantitatively demonstrate changes in the integrin dynamics during osteogenic differentiation of human bone marrow derived progenitor cells (BMPCs). Consistent with the unusually strong BMPC adhesion previously observed, integrins on the surface of undifferentiated BMPC were found in clusters and the lateral diffusion was slow (e.g., approximately 10(-11) cm2/s). At times as early as those after a 3-day incubation in the osteogenic differentiation media, the integrin diffusion coefficients increased by an order of magnitude, and the integrin dynamics became indistinguishable from that measured on the surface of terminally differentiated human osteoblasts. Furthermore, microfilaments in BMPCs consisted of atypically thick bundles of stress fibers that were responsible for restricting the integrin lateral mobility. Studies using laser optical tweezers showed that, unlike fully differentiated osteoblasts, the BMPC cytoskeleton is weakly associated with its cell membrane. Based on these findings, it appears likely that the altered integrin dynamics is correlated with BMPC differentiation and that the integrin lateral mobility is restricted by direct links to microfilaments.

  12. Simple dopant-free hole-transporting materials with p-π conjugated structure for stable perovskite solar cells

    Science.gov (United States)

    Sun, Mengna; Liu, Xueyuan; Zhang, Fei; Liu, Hongli; Liu, Xicheng; Wang, Shirong; Xiao, Yin; Li, Dongmei; Meng, Qingbo; Li, Xianggao

    2017-09-01

    Two simple hole-transporting materials, Me-QTPA and Me-BPZTPA, which consist of p-π conjugated structure, have been synthesized and studied in solid-state perovskite solar cells. Me-QTPA and Me-BPZTPA show outstanding thermal stabilities and appropriate HOMO levels; in addition, these two materials show wide band gaps, thus they can block the electron transport and hence suppress the carrier recombination. The solution-processed CH3NH3PbI3-based device using dopant-free Me-QTPA and Me-BPZTPA can achieve a power conversion efficiency of 9.07% and 8.16%, respectively. The perovskite solar cells with dopant-free Me-QTPA show better performance than the cells with dopant-free spiro-OMeTAD, especially in long-term stability. The power conversion efficiency for the perovskite solar cells with dopant-free Me-QTPA remains almost constant after 600 h. The dopant-free Me-QTPA layer shows strong hydrophobicity with a contact angle of 101.6° to water, which indicates that Me-QTPA has a promising long-term stability at room temperature.

  13. Cell-penetrating peptide-doxorubicin conjugate loaded NGR-modified nanobubbles for ultrasound triggered drug delivery.

    Science.gov (United States)

    Lin, Wen; Xie, Xiangyang; Deng, Jianping; Liu, Hui; Chen, Ying; Fu, Xudong; Liu, Hong; Yang, Yang

    2016-01-01

    A new drug-targeting system for CD13(+) tumors has been developed, based on ultrasound-sensitive nanobubbles (NBs) and cell-permeable peptides (CPPs). Here, the CPP-doxorubicin conjugate (CPP-DOX) was entrapped in the asparagine-glycine-arginine (NGR) peptide modified NB (CPP-DOX/NGR-NB) and the penetration of CPP-DOX was temporally masked; local ultrasound stimulation could trigger the CPP-DOX release from NB and activate its penetration. The CPP-DOX/NGR-NBs had particle sizes of about 200 nm and drug entrapment efficiency larger than 90%. In vitro release results showed that over 85% of the encapsulated DOX or CPP-DOX would release from NBs in the presence of ultrasound, while less than 1.5% of that (30 min) without ultrasound. Cell experiments showed the higher cellular CPP-DOX uptake of CPP-DOX/NGR-NB among the various NB formulations in Human fibrosarcoma cells (HT-1080, CD13(+)). The CPP-DOX/NGR-NB with ultrasound treatment exhibited an increased cytotoxic activity than the one without ultrasound. In nude mice xenograft of HT-1080 cells, CPP-DOX/NGR-NB with ultrasound showed a higher tumor inhibition effect (3.1% of T/C%, day 24), longer median survival time (50 days) and excellent body safety compared with the normal DOX injection group. These results indicate that the constructed vesicle would be a promising drug delivery system for specific cancer treatment.

  14. Bacteriophytochromes control conjugation in Agrobacterium fabrum.

    Science.gov (United States)

    Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

    2016-08-01

    Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation.

  15. Ultrafast dynamics of charge carrier photogeneration and geminate recombination in conjugated polymer:fullerene solar cells

    Science.gov (United States)

    Müller, J. G.; Lupton, J. M.; Feldmann, J.; Lemmer, U.; Scharber, M. C.; Sariciftci, N. S.; Brabec, C. J.; Scherf, U.

    2005-11-01

    We investigate the nature of ultrafast exciton dissociation and carrier generation in acceptor-doped conjugated polymers. Using a combination of two-pulse femtosecond spectroscopy with photocurrent detection, we compare the exciton dissociation and geminate charge recombination dynamics in blends of two conjugated polymers, MeLPPP [methyl-substituted ladder-type poly( p -phenylene)] and MDMO-PPV [poly(2-methoxy,5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene], with the electron accepting fullerene derivative PCBM [1-(3-methoxycarbonyl)-propyl-1-phenyl- (6,6)C61 ]. This technique allows us to distinguish between free charge carriers and Coulombically bound polaron pairs. Our results highlight the importance of geminate pair recombination in photovoltaic devices, which limits the device performance. The comparison of different materials allows us to address the dependence of geminate recombination on the film morphology directly at the polymer:fullerene interface. We find that in the MeLPPP:PCBM blend exciton dissociation generates Coulombically bound geminate polaron pairs with a high probability for recombination, which explains the low photocurrent yield found in these samples. In contrast, in the highly efficient MDMO-PPV:PCBM blend the electron transfer leads to the formation of free carriers. The anisotropy dynamics of electronic transitions from neutral and charged states indicate that polarons in MDMO-PPV relax to delocalized states in ordered domains within 500fs . The results suggest that this relaxation enlarges the distance of carrier separation within the geminate pair, lowering its binding energy and favoring full dissociation. The difference in geminate pair recombination concurs with distinct dissociation dynamics. The electron transfer is preceded by exciton migration towards the PCBM sites. In MeLPPP:PCBM the exciton migration time decays smoothly with increasing PCBM concentration, indicating a trap-free exciton hopping. In MDMO-PPV:PCBM, however

  16. Synthesis of a new conjugated polymer composed of pyrene and bithiophene units for organic solar cells.

    Science.gov (United States)

    Lee, Sun-Young; Jung, Choong-Hwa; Kang, Jun; Kim, Hee-Joon; Shin, Won Suk; Yoon, Sung Cheol; Moon, Sang-Jin; Lee, Changjin; Hwang, Do-Hoon

    2011-05-01

    An alternating conjugated copolymer composed of pyrene and bithiophene units, poly(DHBT-alt-PYR) has been synthesized. The synthesized polymer was found to exhibit good solution processibility and thermal stability, losing less than 5% of their weight on heating to approximately 370 degrees C. The synthesized polymer showed its maximum absorption and peak PL emission at 401 and 548 nm, respectively. The optical band gap energy of the polymer was determined by absorption onset to be 2.64 eV. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polymer was determined to be -5.48 and -2.84 eV by cyclic voltametry (CV) and the optical band gap. The polymer photovoltaic devices were fabricated with a typical sandwich structure of ITO/PEDOT:PSS/active layer/LiF/Al using poly(DHBT-alt-PYR) as an electron donor and C60-PCBM or C70-PCBM as electron acceptors. The open circuit voltage, short circuit current and fill factor of the device using C70-PCBM as an acceptor were 0.75 V, 3.80 mA/cm2 and 0.28, respectively, and the maximum power conversion efficiency of the device was 0.80%.

  17. Renal cysteine conjugate C-S lyase mediated toxicity of halogenated alkenes in primary cultures of human and rat proximal tubular cells.

    Science.gov (United States)

    McGoldrick, Trevor A; Lock, Edward A; Rodilla, Vicente; Hawksworth, Gabrielle M

    2003-07-01

    Proximal tubular cells from human (HPT) and rat (RPT) kidneys were isolated, grown to confluence and incubated with S-(1,2-dichlorovinyl)- l-cysteine (DCVC), S-(1,2,2-trichlorovinyl)- l-cysteine (TCVC), S-(1,1,2,2-tetrafluoroethyl)- l-cysteine (TFEC) and S-(2-chloro-1,1-difluorethyl)- l-cysteine (CDFEC), the cysteine conjugates of nephrotoxicants. The cultures were exposed to the conjugates for 12, 24 and 48 h and the toxicity determined using the MTT assay. All four conjugates caused dose-dependent toxicity to RPT cells over the range 50-1,000 microM, the order of toxicity being DCVC>TCVC>TFEC=CDFEC. The inclusion of aminooxyacetic acid (AOAA; 250 microM), an inhibitor of pyridoxal phosphate-dependent enzymes such as C-S lyase, afforded protection, indicating that C-S lyase has a role in the bioactivation of these conjugates. In HPT cultures only DCVC caused significant time- and dose-dependent toxicity. Exposure to DCVC (500 microM) for 48 h decreased cell viability to 7% of control cell values, whereas co-incubation of DCVC (500 microM) with AOAA (250 microM) resulted in cell viability of 71%. Human cultures were also exposed to S-(1,2-dichlorovinyl)-glutathione (DCVG). DCVG was toxic to HPT cells, but the onset of toxicity was delayed compared with the corresponding cysteine conjugate. AOAA afforded almost complete protection from DCVG toxicity. Acivicin (250 microM), an inhibitor of gamma-glutamyl transferase (gamma-GT), partially protected against DCVG (500 microM)-induced toxicity at 48 h (5% viability and 53% viability in the absence and presence of acivicin, respectively). These results suggest that DCVG requires processing by gamma-GT prior to bioactivation by C-S lyase in HPT cells. The activity of C-S lyase, using TFEC as a substrate, and glutamine transaminase K (GTK) was measured in rat and human cells with time in culture. C-S lyase activity in RPT and HPT cells decreased to approximately 30% of fresh cell values by the time the cells reached

  18. Inhibitory effect of gold nanoparticles conjugated with interferon gamma and methionine on breast cancer cell line

    Directory of Open Access Journals (Sweden)

    Nastaran Mohseni

    2016-02-01

    Conclusions: The size and concentration of gold nanorods was not cytotoxic. However, their presence during irradiation near-infrared laser increased the number of dead cells during the treatment of cells.

  19. Growth arrest of BCR-ABL positive cells with a sequence-specific polyamide-chlorambucil conjugate.

    Directory of Open Access Journals (Sweden)

    C James Chou

    Full Text Available Chronic myeloid leukemia (CML is characterized by the presence of a constitutively active Abl kinase, which is the product of a chimeric BCR-ABL gene, caused by the genetic translocation known as the Philadelphia chromosome. Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML. However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML. Although alternative Bcr-Abl tyrosine kinase inhibitors have been developed to overcome drug resistance, a cocktail therapy of different kinase inhibitors and additional chemotherapeutics may be needed for complete remission of CML in some cases. Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease. Here we report that a DNA sequence-specific pyrrole-imidazole polyamide-chlorambucil conjugate, 1R-Chl, causes growth arrest of cells harboring both unmutated BCR-ABL and three imatinib resistant strains. 1R-Chl also displays selective toxicities against activated lymphocytes and a high dose tolerance in a murine model.

  20. Growth Arrest of BCR-ABL Positive Cells with a Sequence-Specific Polyamide-Chlorambucil Conjugate

    Science.gov (United States)

    Chou, C. James; O'Hare, Thomas; Lefebvre, Sophie; Alvarez, David; Tyner, Jeffrey W.; Eide, Christopher A.; Druker, Brian J.; Gottesfeld, Joel M.

    2008-01-01

    Chronic myeloid leukemia (CML) is characterized by the presence of a constitutively active Abl kinase, which is the product of a chimeric BCR-ABL gene, caused by the genetic translocation known as the Philadelphia chromosome. Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML. However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML. Although alternative Bcr-Abl tyrosine kinase inhibitors have been developed to overcome drug resistance, a cocktail therapy of different kinase inhibitors and additional chemotherapeutics may be needed for complete remission of CML in some cases. Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease. Here we report that a DNA sequence-specific pyrrole-imidazole polyamide-chlorambucil conjugate, 1R-Chl, causes growth arrest of cells harboring both unmutated BCR-ABL and three imatinib resistant strains. 1R-Chl also displays selective toxicities against activated lymphocytes and a high dose tolerance in a murine model. PMID:18974832

  1. New π-Conjugated Materials Based on Furylenevinylene Candidate for Organic Solar Cells Application: A DFT Study

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    El Alamy Aziz

    2015-12-01

    Full Text Available The specific properties of organic-conjugated molecules and polymers are of great importance since they have become the most promising materials for the optoelectronic device technology such as solar cells. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the parameters of these materials is a research issue of ongoing interest. In this work, a quantum chemical investigation was performed to explore the optical and electronic properties of a series of different compounds based on furylenevinylene. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO energy levels of the components is basic in studying organic solar cells; so the HOMO, LUMO, Gap energy and open circuit voltage (Voc of the studied compounds have been calculated and reported. These properties suggest that these materials behave as good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v7i4.763 

  2. [Bioconversion of conjugated linoleic acid by resting cells of Lactobacillus plantarum ZS2058 in potassium phosphate buffer system].

    Science.gov (United States)

    Niu, Xiao-yan; Chen, Wei; Tian, Feng-wei; Zhao, Jian-xin; Zhang, Hao

    2007-04-01

    Lactobacillus plantarum ZS2058, which was screened from the Chinese traditional fermented vegetable, has the capacity to convert the linoleic acid (LA) into conjugated linoleic acid (CLA). Some specific isomers of CLA with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from free linoleic acid by washed cells of Lactobacillus plantarum ZS2058 under aerobic conditions. The produced CLA isomers are identified as the mixture of cis-9, trans-ll-octadecadienoic acid (CLA1) trans-10, cis-12-octadecadienoic acid (CLA2), 96.4% of which is CLA1. The washed cells of Lactobacillus plantarum ZS2058 producing high levels of c9, t11-CLA were obtained by cultivated in MRS media containing 0.5 mg/mL linoleic acid, indicating that the enzyme system for CLA production is induced by linoleic acid. After a 24-hour bioconversion at 37 degrees C with shaking (120 r/min), 312.4 microg/mL c9, t11-CLA is produced. And after a 36-hour bioconversion, the content of c9, t11-CLA decreases while hydroxy-octadecaenoic acid increases. In addition, the c9, t11-CLA isomer can be transformed to hydroxy- octadecaenoic acid when the mixed CLA (c9, t11-CLA and t10, c12-CLA) were used as the substrate, which suggests that c9, t11-CLA is one of the intermediates of the bioconversion products from free LA by washed cells of Lactobacillus plantarum ZS2058.

  3. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    Science.gov (United States)

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-05

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  4. Metabolic and growth inhibitory effects of conjugated fatty acids in the cell line HT-29 with special regard to the conversion of t11,t13-CLA.

    Science.gov (United States)

    Degen, Christian; Ecker, Josef; Piegholdt, Stefanie; Liebisch, Gerhard; Schmitz, Gerd; Jahreis, Gerhard

    2011-12-01

    Conjugated fatty acids (CFAs) exhibit growth inhibitory effects on colon cancer in vitro and in vivo. To investigate whether the anticancerogenic potency depends on number or configuration of the conjugated double bonds, the effect of conjugated linoleic acid (CLA; C18:2) isomers and conjugated linolenic acid (CLnA; C18:3) isomers on viability and growth of HT-29 cells were compared. Low concentrations of CLnAs (t11,t13-CLA≥t9,t11-CLA>c9,t11-CLA. The mRNA expression analysis of important genes associated with fatty acid metabolism showed an absence of ∆5-/∆6-desaturases and elongases in HT-29 cells, which was confirmed by fatty acid analysis. Using time- and dose-dependent stimulation experiments several metabolites were determined. Low concentrations of all trans-CFAs (5-20μM) led to dose-dependent increase of conjugated t/t-C16:2 formed by β-oxidation of C18 CFAs, ranging from 1-5% of total FAME. Importantly, it was found that CLnA is converted to CLA and that CLA is inter-converted (t11,t13-CLA is metabolized to c9,t11-CLA) by HT-29 cells. In summary, our study shows that growth inhibition of human cancer cells is associated with a specific cellular transcriptomic and metabolic profile of fatty acid metabolism, which might contribute to the diversified ability of CFAs as anti-cancer compounds.

  5. Design, synthesis, and in vitro and in vivo biological studies of a 3'-deoxythymidine conjugate that potentially kills cancer cells selectively.

    Directory of Open Access Journals (Sweden)

    Qiong Wei

    Full Text Available Thymidine kinases (TKs have been considered one of the potential targets for anticancer therapeutic because of their elevated expressions in cancer cells. However, nucleobase analogs targeting TKs have shown poor selective cytotoxicity in cancer cells despite effective antiviral activity. 3'-Deoxythymidine phenylquinoxaline conjugate (dT-QX was designed as a novel nucleobase analog to target TKs in cancer cells and block cell replication via conjugated DNA intercalating quinoxaline moiety. In vitro cell screening showed that dT-QX selectively kills a variety of cancer cells including liver carcinoma, breast adenocarcinoma and brain glioma cells; whereas it had a low cytotoxicity in normal cells such as normal human liver cells. The anticancer activity of dT-QX was attributed to its selective inhibition of DNA synthesis resulting in extensive mitochondrial superoxide stress in cancer cells. We demonstrate that covalent linkage with 3'-deoxythymidine uniquely directed cytotoxic phenylquinoxaline moiety more toward cancer cells than normal cells. Preliminary mouse study with subcutaneous liver tumor model showed that dT-QX effectively inhibited the growth of tumors. dT-QX is the first molecule of its kind with highly amendable constituents that exhibits this selective cytotoxicity in cancer cells.

  6. Bulk Heterojunction Solar Cells Based on Blends of Conjugated Polymers with II–VI and IV–VI Inorganic Semiconductor Quantum Dots

    Directory of Open Access Journals (Sweden)

    Ryan Kisslinger

    2017-01-01

    Full Text Available Bulk heterojunction solar cells based on blends of quantum dots and conjugated polymers are a promising configuration for obtaining high-efficiency, cheaply fabricated solution-processed photovoltaic devices. Such devices are of significant interest as they have the potential to leverage the advantages of both types of materials, such as the high mobility, band gap tunability and possibility of multiple exciton generation in quantum dots together with the high mechanical flexibility and large molar extinction coefficient of conjugated polymers. Despite these advantages, the power conversion efficiency (PCE of these hybrid devices has remained relatively low at around 6%, well behind that of all-organic or all-inorganic solar cells. This is attributed to major challenges that still need to be overcome before conjugated polymer–quantum dot blends can be considered viable for commercial application, such as controlling the film morphology and interfacial structure to ensure efficient charge transfer and charge transport. In this work, we present our findings with respect to the recent development of bulk heterojunctions made from conjugated polymer–quantum dot blends, list the ongoing strategies being attempted to improve performance, and highlight the key areas of research that need to be pursued to further develop this technology.

  7. Phytosynthesis of gold nanoparticles using Mappia foetida leaves extract and their conjugation with folic acid for delivery of doxorubicin to cancer cells.

    Science.gov (United States)

    Yallappa, S; Manjanna, J; Dhananjaya, B L; Vishwanatha, U; Ravishankar, B; Gururaj, H

    2015-09-01

    Mappia foetida leaves extract is used as bioreductant for the synthesis of gold nanoparticles and their application in the efficient delivery of doxorubicin to human cancer cells is reported here. The formation of gold nanoparticles is evident from their characteristic optical absorption at ~560 nm. X-ray diffraction pattern of gold nanoparticles confirmed their fcc structure. Fourier transform infrared spectroscopy shows the bioactive molecules from plant extract capped on the surface of gold nanoparticles and conjugation of doxorubicin along with activated folic acid as navigational molecules for targeted drug delivery. Such a conjugation of gold nanoparticles is characterized by their weight loss, ~35-40 %, due to thermal degradation of plant biomass and conjugated drug along with receptor, as observed in thermogravimetric analysis. The spherical shaped gold nanoparticles (Φ 10-20 nm) are observed by field emission scanning electron microscopy and transmission electron microscopy images and the expected elemental composition by energy dispersive X-ray spectroscopy. Gold nanoparticles conjugated with activated folic acid and doxorubicin complex is found to be toxic for human cancer cells viz., MDA-MB-231, HeLa, SiHa and Hep-G2. Furthermore, the amount of drug released was maximum at pH 5.3 (an ambient condition for intravenous cancer drugs) followed by pH 7.2 and pH 6.8.

  8. Understanding the Light Soaking Effects in Inverted Organic Solar Cells Functionalized with Conjugated Macroelectrolyte Electron-Collecting Interlayers.

    Science.gov (United States)

    Xu, Weidong; Xia, Ruidong; Ye, Tengling; Zhao, Li; Kan, Zhipeng; Mei, Yang; Yan, Congfei; Zhang, Xin-Wen; Lai, Wen-Yong; Keivanidis, Panagiotis E; Huang, Wei

    2016-02-01

    Three kinds of charged star-shaped conjugated macroelectrolytes, named as PhNBr, TPANBr, and TrNBr, are synthesized as electron-collecting interlayers for inverted polymer solar cells (i-PSCs). Based on these well-defined structured interlayer materials, the light soaking (LS) effect observed in i-PSCs was studied systematically and accurately. The general character of the LS effect is further verified by studying additional i-PSC devices functionalized with other common interlayers. The key-role of UV photons was confirmed by electrochemical impedance spectroscopy and electron-only devices. In addition, the ultraviolet photoelectron spectroscopy measurements indicate that the work function of the indium tin oxide (ITO)/interlayer cathode is significantly reduced after UV treatment. In these i-PSC devices the LS effect originates from the adsorbed oxygen on the ITO substrates when oxygen plasma is used; however, even a small amount of oxygen from the ambient is also enough for triggering the LS effect, albeit with a weaker intensity. Our results suggest that the effect of adsorbed oxygen on ITO needs to be considered with attention while preparing i-PSCs. This is an important finding that can aid the large-scale manufacturing of organic solar cells via printing technologies, which do not always ensure the full protection of the device electrode substrates from oxygen.

  9. Prostate stem cell antigen antibody-conjugated multiwalled carbon nanotubes for targeted ultrasound imaging and drug delivery.

    Science.gov (United States)

    Wu, Huixia; Shi, Haili; Zhang, Hao; Wang, Xue; Yang, Yan; Yu, Chao; Hao, Caiqin; Du, Jing; Hu, He; Yang, Shiping

    2014-07-01

    Multiwalled carbon nanotubes (MWCNTs) are cut short and grafted with polyethylenimine (PEI) for further covalent conjugation to fluorescein isothiocyanate (FITC) and prostate stem cell antigen (PSCA) monoclonal antibody (mAb). The in vitro and in vivo toxicity data reveal that the as-prepared CNT-PEI(FITC)-mAb has good biocompatibility. Combined flow cytometry and confocal luminescence imaging experiments confirm that the CNT-PEI(FITC)-mAb can specifically target the cancer cells which overexpress PSCA. The results of in vitro and in vivo ultrasound (US) imaging indicate that CNT-PEI(FITC)-mAb has great potential to be used as a targeted US contrast agent. The in vivo anti-cancer efficacy testing using PC-3 tumor-bearing mice as animal models demonstrates that CNT-PEI(FITC)-mAb can targetedly deliver drug to the tumors and suppress tumor growth. Findings from this study suggest that the CNT-PEI(FITC)-mAb could be used as a multifunctional platform for simultaneous US imaging and drug delivery applications.

  10. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Ilona M. Heckler

    2016-03-01

    Full Text Available The stability of polymer solar cells (PSCs can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyldialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT or thiazolo[5,4-d]thiazole (TzTz acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10% of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs’ lifetime.

  11. Anthracene-containing wide-band-gap conjugated polymers for high-open-circuit-voltage polymer solar cells.

    Science.gov (United States)

    Gong, Xue; Li, Cuihong; Lu, Zhen; Li, Guangwu; Mei, Qiang; Fang, Tao; Bo, Zhishan

    2013-07-25

    The synthesis, characterization, and photophysical and photovoltaic properties of two anthracene-containing wide-band-gap donor and acceptor (D-A) alternating conjugated polymers (P1 and P2) are described. These two polymers absorb in the range of 300-600 nm with a band gap of about 2.12 eV. Polymer solar cells with P1:PC71 BM as the active layer demonstrate a power conversion efficiency (PCE) of 2.23% with a high Voc of 0.96 V, a Jsc of 4.4 mA cm(-2) , and a comparable fill factor (FF) of 0.53 under simulated solar illumination of AM 1.5 G (100 mW cm(-2) ). In addition, P2:PC71 BM blend-based solar cells exhibit a PCE of 1.42% with a comparable Voc of 0.89 V, a Jsc of 3.0 mA cm(-2) , and an FF of 0.53. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Crafting semiconductor organic-inorganic nanocomposites via placing conjugated polymers in intimate contact with nanocrystals for hybrid solar cells.

    Science.gov (United States)

    Zhao, Lei; Lin, Zhiqun

    2012-08-22

    Semiconductor organic-inorganic hybrid solar cells incorporating conjugated polymers (CPs) and nanocrystals (NCs) offer the potential to deliver efficient energy conversion with low-cost fabrication. The CP-based photovoltaic devices are complimented by an extensive set of advantageous characteristics from CPs and NCs, such as lightweight, flexibility, and solution-processability of CPs, combined with high electron mobility and size-dependent optical properties of NCs. Recent research has witnessed rapid advances in an emerging field of directly tethering CPs on the NC surface to yield an intimately contacted CP-NC nanocomposite possessing a well-defined interface that markedly promotes the dispersion of NCs within the CP matrix, facilitates the photoinduced charge transfer between these two semiconductor components, and provides an effective platform for studying the interfacial charge separation and transport. In this Review, we aim to highlight the recent developments in CP-NC nanocomposite materials, critically examine the viable preparative strategies geared to craft intimate CP-NC nanocomposites and their photovoltaic performance in hybrid solar cells, and finally provide an outlook for future directions of this extraordinarily rich field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Aptamer-conjugated live human immune cell based biosensors for the accurate detection of C-reactive protein

    Science.gov (United States)

    Hwang, Jangsun; Seo, Youngmin; Jo, Yeonho; Son, Jaewoo; Choi, Jonghoon

    2016-10-01

    C-reactive protein (CRP) is a pentameric protein that is present in the bloodstream during inflammatory events, e.g., liver failure, leukemia, and/or bacterial infection. The level of CRP indicates the progress and prognosis of certain diseases; it is therefore necessary to measure CRP levels in the blood accurately. The normal concentration of CRP is reported to be 1-3 mg/L. Inflammatory events increase the level of CRP by up to 500 times; accordingly, CRP is a biomarker of acute inflammatory disease. In this study, we demonstrated the preparation of DNA aptamer-conjugated peripheral blood mononuclear cells (Apt-PBMCs) that specifically capture human CRP. Live PBMCs functionalized with aptamers could detect different levels of human CRP by producing immune complexes with reporter antibody. The binding behavior of Apt-PBMCs toward highly concentrated CRP sites was also investigated. The immune responses of Apt-PBMCs were evaluated by measuring TNF-alpha secretion after stimulating the PBMCs with lipopolysaccharides. In summary, engineered Apt-PBMCs have potential applications as live cell based biosensors and for in vitro tracing of CRP secretion sites.

  14. Fluorescence Ratiometric Assay Strategy for Chemical Transmitter of Living Cells Using H2O2-Sensitive Conjugated Polymers.

    Science.gov (United States)

    Wang, Yunxia; Li, Shengliang; Feng, Liheng; Nie, Chenyao; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-11-01

    A new water-soluble conjugated poly(fluorene-co-phenylene) derivative (PFP-FB) modified with boronate-protected fluorescein (peroxyfluor-1) via PEG linker has been designed and synthesized. In the presence of H2O2, the peroxyfluor-1 group can transform into green fluorescent fluorescein by deprotecting the boronate protecting groups. In this case, upon selective excitation of PFP-FB backbone at 380 nm, efficient fluorescence resonance energy transfer (FRET) from PFP-FB backbone to fluorescein occurs, and accordingly, the fluorescence color of PFP-FB changes from blue to green. Furthermore, the emission color of PFP-FB and the FRET ratio change in a concentration-dependent manner. By taking advantage of PFP-FB, ratiometric detection of choline and acetylcholine (ACh) through cascade enzymatic reactions and further dynamic monitoring of the choline consumption process of cancer cells have been successfully realized. Thus, this new polymer probe promotes the development of enzymatic biosensors and provides a simpler and more effective way for detecting the chemical transmitter of living cells.

  15. Hemocompatible pullulan-polyethyleneimine conjugates for liver cell gene delivery: In vitro evaluation of cellular uptake, intracellular trafficking and transfection efficiency.

    Science.gov (United States)

    Rekha, M R; Sharma, Chandra P

    2011-01-01

    Polyethyleneimine (PEI; 25 kDa)-conjugated pullulans (PPE1, PPE2 and PPE3) were developed and investigated for possible use in gene delivery applications. The cytotoxicity, blood component interactions such as red blood cell/white blood cell aggregation, platelet and complement activation, and protein interaction of the pullulan-conjugated PEI was drastically reduced in comparison to PEI-based nanocomplexes. Based on the blood compatibility studies, PPE1 was selected for further study. The buffering capacity of this derivative was similar to that of PEI, which plays an important role in efficient gene transfection. The particle size, zeta potential, stability in the presence of plasma and resistance to nuclease degradation were evaluated. In addition, cellular uptake and localization of plasmid, as well as transgene expression, were evaluated following in vitro transfection of HepG2 cells. Endocytosis inhibitors, confocal laser scanning microscopy and fluorescent labeling techniques were used to visualize the nanoplex uptake mechanism, cellular distribution and nuclear localization. The results from inhibitor experiments in the presence of asialofetuin indicated that the asialoglycoprotein receptor is involved in transfection of hepatocytes with pullulan-PEI complexes. The conjugation of pullulan with PEI did not hinder the plasmid nuclear localization ability of PEI. The transfection efficiency of pullulan conjugate was similar to PEI, with the added advantage of hemocompatibility and non-cytotoxicity. The transfection efficiency of PEI and PPE1 was 1.6- and 2-fold more, respectively, in the presence of serum than in the absence of serum. Therefore, the pullulan-PEI conjugate seems to be a promising gene delivery vector with good hemocompatibility and low toxicity but without compromising the transfection efficacy of PEI.

  16. HIV-1 efficient entry in inner foreskin is mediated by elevated CCL5/RANTES that recruits T cells and fuels conjugate formation with Langerhans cells.

    Directory of Open Access Journals (Sweden)

    Zhicheng Zhou

    2011-06-01

    Full Text Available Male circumcision reduces acquisition of HIV-1 by 60%. Hence, the foreskin is an HIV-1 entry portal during sexual transmission. We recently reported that efficient HIV-1 transmission occurs following 1 h of polarized exposure of the inner, but not outer, foreskin to HIV-1-infected cells, but not to cell-free virus. At this early time point, Langerhans cells (LCs and T-cells within the inner foreskin epidermis are the first cells targeted by the virus. To gain in-depth insight into the molecular mechanisms governing inner foreskin HIV-1 entry, foreskin explants were inoculated with HIV-1-infeceted cells for 4 h. The chemokine/cytokine milieu secreted by the foreskin tissue, and resulting modifications in density and spatial distribution of T-cells and LCs, were then investigated. Our studies show that in the inner foreskin, inoculation with HIV-1-infected cells induces increased CCL5/RANTES (1.63-fold and decreased CCL20/MIP-3-alpha (0.62-fold secretion. Elevated CCL5/RANTES mediates recruitment of T-cells from the dermis into the epidermis, which is blocked by a neutralizing CCL5/RANTES Ab. In parallel, HIV-1-infected cells mediate a bi-phasic modification in the spatial distribution of epidermal LCs: attraction to the apical surface at 1 h, followed by migration back towards the basement membrane later on at 4 h, in correlation with reduced CCL20/MIP-3-alpha at this time point. T-cell recruitment fuels the continuous formation of LC-T-cell conjugates, permitting the transfer of HIV-1 captured by LCs. Together, these results reveal that HIV-1 induces a dynamic process of immune cells relocation in the inner foreskin that is associated with specific chemokines secretion, which favors efficient HIV-1 entry at this site.

  17. Comparison between conjugated linoleic acid and essential fatty acids in preventing oxidative stress in bovine mammary epithelial cells.

    Science.gov (United States)

    Basiricò, L; Morera, P; Dipasquale, D; Tröscher, A; Bernabucci, U

    2017-03-01

    Some in vitro and in vivo studies have demonstrated protective effects of conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation. However, only a few and conflicting studies have been conducted showing the antioxidant potential of essential fatty acids. The objectives of the study were to compare the effects of CLA to other essential fatty acids on the thiol redox status of bovine mammary epithelia cells (BME-UV1) and their protective role against oxidative damage on the mammary gland by an in vitro study. The BME-UV1 cells were treated with complete medium containing 50 μM of cis-9,trans-11 CLA, trans-10,cis-12 CLA, α-linolenic acid, γ-linolenic acid, and linoleic acid. To assess the cellular antioxidant response, glutathione, NADPH, and γ-glutamyl-cysteine ligase activity were measured 48 h after addition of fatty acids (FA). Intracellular reactive oxygen species and malondialdehyde production were also assessed in cells supplemented with FA. Reactive oxygen species production after 3 h of H2O2 exposure was assessed to evaluate and to compare the potential protection of different FA against H2O2-induced oxidative stress. All FA treatments induced an intracellular GSH increase, matched by high concentrations of NADPH and an increase of γ-glutamyl-cysteine ligase activity. Cells supplemented with FA showed a reduction in intracellular malondialdehyde levels. In particular, CLA isomers and linoleic acid supplementation showed a better antioxidant cellular response against oxidative damage induced by H2O2 compared with other FA. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  18. Preparation of conjugated polymer-based composite thin film for application in solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang-Yen, E-mail: yyyu@mail.mcut.edu.tw [Department of Materials Engineering, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Battery Research Center of Green Energy, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Center for Thin Film Technologies and Applications, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Chien, Wen-Chen [Department of Chemical Engineering, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Battery Research Center of Green Energy, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Ko, Yu-Hsin [Department of Materials Engineering, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Chen, Chih-Ping [Department of Materials Engineering, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Battery Research Center of Green Energy, Ming Chi University of Technology, 84 Gunjuan Road, Taishan, New Taipei City 243, Taiwan (China); Chang, Chao-Ching [Department of Chemical and Materials Engineering, Tamkang University, 151, Yingzhuan Rd., Tamsui Dist., New Taipei City 25137, Taiwan (China)

    2015-06-01

    This paper reports on the enhanced cell efficiency of structures and properties of regioregular poly(3-hexylthiophene) (P3HT)/multiwalled carbon nanotube (MWNT) hybrid materials. The prepared hybrid materials were characterized using ultraviolet–visible absorption spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Different concentrations of these MWNTs were suspended in polymer solutions and spin-cast onto indium tin oxide (ITO) glass. Solar cells with a device structure of ITO/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) /P3HT:MWNTs/aluminum were then produced using evaporated aluminum as the back contact. The results showed that the ratio of P3HT to MWNTs considerably influenced the performance of the fabricated solar cells. The efficiency of the solar cells increased with the ratio of carbon nanotubes. Monochromatic incident photon-to-electron conversion efficiency analysis was performed and the results indicated that at the optimal P3HT/MWNTs ratio (= 1/1), the solar cells demonstrated a high-quality conversion of 2.16% with a fill factor of 42.22%, an open circuit voltage of 0.56 V, and a short circuit current of 9.12 mA/cm{sup 2}. - Highlights: • Solar cells ITO/PEDOT:PSS(DMSO)/P3HT:MWNT/Al were fabricated. • Optimal ratio of P3HT to MWNT was investigated. • Solar cell with 2.16% efficiency was obtained.

  19. Comparison of a mouse and a novel human scFv-SNAP-auristatin F drug conjugate with potent activity against EGFR-overexpressing human solid tumor cells

    Directory of Open Access Journals (Sweden)

    Woitok M

    2017-07-01

    Full Text Available Mira Woitok,1,2 Diana Klose,1 Stefano Di Fiore,1 Wolfgang Richter,3 Christoph Stein,1 Gerrit Gresch,1 Elena Grieger,1 Stefan Barth,1 Rainer Fischer,1,2 Katharina Kolberg,1,* Judith Niesen1,* 1Fraunhofer Institute for Molecular Biology and Applied Ecology (IME, Aachen, Germany; 2Institute of Molecular Biotechnology (Biology VII, RWTH Aachen University, Aachen, Germany; 3Tube Pharmaceuticals GmbH, Vienna, Austria *These authors contributed equally to this work Abstract: Antibody–drug conjugates (ADCs can deliver toxins to specific targets such as tumor cells. They have shown promise in preclinical/clinical development but feature stoichiometrically undefined chemical linkages, and those based on full-size antibodies achieve only limited tumor penetration. SNAP-tag technology can overcome these challenges by conjugating benzylguanine-modified toxins to single-chain fragment variables (scFvs with 1:1 stoichio­metry while preserving antigen binding. Two (human and mouse scFv-SNAP fusion proteins recognizing the epidermal growth factor receptor (EGFR were expressed in HEK 293T cells. The purified fusion proteins were conjugated to auristatin F (AURIF. Binding activity was confirmed by flow cytometry/immunohistochemistry, and cytotoxic activity was confirmed by cell viability/apoptosis and cell cycle arrest assays, and a novel microtubule dynamics disassembly assay was performed. Both ADCs bound specifically to their target cells in vitro and ex vivo, indicating that the binding activity of the scFv-SNAP fusions was unaffected by conjugation to AURIF. Cytotoxic assays confirmed that the ADCs induced apoptosis and cell cycle arrest at nanomolar concentrations and microtubule disassembly. The SNAP-tag technology provides a platform for the development of novel ADCs with defined conjugation sites and stoichiometry. We achieved the stable and efficient linkage of AURIF to human or murine scFvs using the SNAP-tag technology, offering a strategy to

  20. Preparation, characterization and targeting of micronized 10-hydroxycamptothecin-loaded folate-conjugated human serum albumin nanoparticles to cancer cells

    Directory of Open Access Journals (Sweden)

    et al

    2011-02-01

    Full Text Available Qingyong Li, Chen Liu, Xiuhua Zhao, Yuangang Zu, Ying Wang, Baoyou Zhang, Dongmei Zhao, Qi Zhao, Lin Su, Yang Gao, Baihe SunKey Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, Heilongjiang, People's Republic of ChinaBackground: The purpose of this study was to develop a method for targeted delivery of 10-hydroxycamptothecin (HCPT-loaded nanoparticles (NPs to cancer cells.Methods: We first used a supercritical antisolvent process to prepare micronized HCPT (nHCPT, and then folate-conjugated human serum albumin (HSA nHCPT-loaded NPs (FA-HSA-nHCPT-NPs were prepared using a NP-coated method combined with a desolvation technique. The amount of folate conjugation was 16 µg · mg-1 HSA.Results: The particle size of the spherical nHCPT microparticles obtained was 118.5 ± 6.6 nm. The particle size and zeta potential of the FA-HSA-nHCPT-NPs were 233.9 ± 1.2 nm and -25.23 ± 2.98 mV, respectively. The FA-HSA-nHCPT-NPs exhibited a smooth surface and a distinct spherical shape, and the results of differential scanning calorimetry and X-ray diffraction indicated that the FA-HSA-nHCPT-NPs presented in a nanostructured amorphous state. The FA-HSA-nHCPT-NPs showed sustained-release characteristics for 120 hours in vitro, with a drug-loading content of 7.3% and an encapsulating efficiency of 79.1%.Conclusion: The FA-NPs were effective delivery systems for uptake by SGC7901 cells compared with folate-free NPs. These results suggest that a NP-coated method combined with a desolvation technique is effective for preparing NPs with drugs having poor solubility in water and most organic solvents, using albumin as the wall material. FA-HSA-NPs are a stable delivery system and have the potential for targeted delivery of anticancer drugs.Keywords: nanoparticle-coated, desolvation technique, 10-hydroxycamptothecin, human serum albumin, folate, targeted delivery 

  1. Enhanced immunogenicity of a tricomponent mannan tetanus toxoid conjugate vaccine targeted to dendritic cells via Dectin-1 by incorporating β-glucan.

    Science.gov (United States)

    Lipinski, Tomasz; Fitieh, Amira; St Pierre, Joëlle; Ostergaard, Hanne L; Bundle, David R; Touret, Nicolas

    2013-04-15

    In a previous attempt to generate a protective vaccine against Candida albicans, a β-mannan tetanus toxoid conjugate showed poor immunogenicity in mice. To improve the specific activation toward the fungal pathogen, we aimed to target Dectin-1, a pattern-recognition receptor expressed on monocytes, macrophages, and dendritic cells. Laminarin, a β-glucan ligand of Dectin-1, was incorporated into the original β-mannan tetanus toxoid conjugate providing a tricomponent conjugate vaccine. A macrophage cell line expressing Dectin-1 was employed to show binding and activation of Dectin-1 signal transduction pathway by the β-glucan-containing vaccine. Ligand binding to Dectin-1 resulted in the following: 1) activation of Src family kinases and Syk revealed by their recruitment and phosphorylation in the vicinity of bound conjugate and 2) translocation of NF-κB to the nucleus. Treatment of immature bone marrow-derived dendritic cells (BMDCs) with tricomponent or control vaccine confirmed that the β-glucan-containing vaccine exerted its enhanced activity by virtue of dendritic cell targeting and uptake. Immature primary cells stimulated by the tricomponent vaccine, but not the β-mannan tetanus toxoid vaccine, showed activation of BMDCs. Moreover, treated BMDCs secreted increased levels of several cytokines, including TGF-β and IL-6, which are known activators of Th17 cells. Immunization of mice with the novel type of vaccine resulted in improved immune response manifested by high titers of Ab recognizing C. albicans β-mannan Ag. Vaccine containing laminarin also affected distribution of IgG subclasses, showing that vaccine targeting to Dectin-1 receptor can benefit from augmentation and immunomodulation of the immune response.

  2. Cell Adhesion Induced Using Surface Modification with Cell-Penetrating Peptide-Conjugated Poly(ethylene glycol)-Lipid: A New Cell Glue for 3D Cell-Based Structures.

    Science.gov (United States)

    Teramura, Yuji; Asif, Sana; Ekdahl, Kristina N; Gustafson, Elisabet; Nilsson, Bo

    2017-01-11

    We synthesized a novel material, cell-penetrating peptide-conjugated poly(ethylene glycol)-lipid (CPP-PEG-lipid), that can induce the adhesion of floating cells. Firm cell adhesion with spreading could be induced by cell surface modification with the CPP-PEG-lipids. Cell adhesion was induced by CPPs but not by any other cationic short peptides we tested. Here, we demonstrated adherence using the floating cell line CCRF-CEM as well as primary human T cells, B cells, erythrocytes, and hepatocytes. As compared to cells grown in suspension, adherent cells were more rapidly induced to attach to substrates with the cell-surface modification. The critical factor for attachment was localization of CPPs at the cell membrane by PEG-lipids with PEG > 20 kDa. These cationic CPPs on PEG chains were able to interact with substrate surfaces such as polystyrene (PS) surfaces, glass surfaces, and PS microfibers that are negatively charged, inducing firm cell adhesion and cell spreading. Also, as opposed to normal cationic peptides that interact strongly with cell membranes, CPPs were less interactive with the cell surfaces because of their cell-penetrating property, making them more available for adhering cells to the substrate surface. No effects on cell viability or cell proliferation were observed after the induction of cell adhesion. With this technique, cells could be easily immobilized onto PS microfibers, an important step in fabricating 3D cell-based structures. Cells immobilized onto 3D PS microfibers were alive, and human hepatocytes showed normal production of urea and albumin on the microfibers. This method is novel in inducing firm cell adhesion via a one-step treatment.

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

    Science.gov (United States)

    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 viareduction 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 μg 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.

  4. Hydroxycinnamate Conjugates as Potential Monolignol Replacements: In vitro Lignification and Cell Wall Studies with Rosmarinic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Yuki, Tobimatsu; Sasikumar, Elumalai; Grabber, John H.; Davidson, Christy L.; Xuejun, Pan; John, Ralph

    2012-04-01

    The plasticity of lignin biosynthesis should permit the inclusion of new compatible phenolic monomers, such as rosmarinic acid (RA) and analogous catechol derivatives, into cell-wall lignins that are consequently less recalcitrant to biomass processing. In vitro lignin polymerization experiments revealed that RA readily underwent peroxidase-catalyzed copolymerization with monolignols and lignin oligomers to form polymers with new benzodioxane inter-unit linkages. Incorporation of RA permitted extensive depolymerization of synthetic lignins by mild alkaline hydrolysis, presumably by cleavage of ester intra-unit linkages within RA. Copolymerization of RA with monolignols into maize cell walls by in situ peroxidases significantly enhanced alkaline lignin extractability and promoted subsequent cell wall saccharification by fungal enzymes. Incorporating RA also improved cell wall saccharification by fungal enzymes and by rumen microflora even without alkaline pretreatments, possibly by modulating lignin hydrophobicity and/or limiting cell wall cross-linking. Consequently, we anticipate that bioengineering approaches for partial monolignol substitution with RA and analogous plant hydroxycinnamates would permit more efficient utilization of plant fiber for biofuels or livestock production.

  5. Enhanced drug loading on magnetic nanoparticles by layer-by-layer assembly using drug conjugates: blood compatibility evaluation and targeted drug delivery in cancer cells.

    Science.gov (United States)

    Manju, S; Sreenivasan, K

    2011-12-06

    Drug targeting using magnetic nanoparticles (MNPs) under the action of an external magnetic field constitutes an important mode of drug delivery. Low cargo capacity, particularly in hydrophobic drugs, is one limitation shown by MNPs. This article describes a simple strategy to enhance the drug-loading capacity of MNPs. The approach was to use polymer-drug conjugates to modify MNPs by layer-by-layer assembly (LbL). Curcumin (CUR) has shown remarkably high cytotoxicity toward various cancer cell lines. However, the drug shows low anticancer activity in vivo because of its reduced systemic bioavailability acquired from its poor aqueous solubility and instability. To address this issue, we synthesized cationic and anionic CUR conjugates by anchoring CUR onto poly(vinylpyrroidone) (PVP-Cur) and onto hyaluronic acid (HA-Cur). We used these oppositely charged conjugates to modify MNPs by layer-by-layer (LbL) assembly. Six double layers of curcumin conjugates were constructed on positively charged amino-terminated magnetic nanoparticles, TMSPEDA@MNPs. Finally, HA was coated onto the outer surface to form HA (HA-Cur/PVP-Cur)(6)@MNPs. Cellular viability studies showed the dose-dependent antiproliferative effect of HA (HA-Cur/PVP-Cur)(6)@MNPs in two cancer cell lines (glioma cells and Caco-2 cells). HA (HA-Cur/PVP-Cur)(6)@MNPs exhibited more cytotoxicity than did free curcumin, which was attributed to the enhanced solubility along with better absorption via hyaluronic acid receptor-mediated endocytosis. Flow cytometry showed enhanced intake of the modified MNPs by cells. Confocal microscope images also confirmed the uptake of HA (HA-Cur/PVP-Cur)(6)@MNPs with greater efficacy. Thus, the strategy that we adopted here appears to have substantial potential in carrying enhanced payloads of hydrophobic drugs to specified targets. © 2011 American Chemical Society

  6. RGD-conjugated gold nanorods induce radiosensitization in melanoma cancer cells by downregulating αvβ3 expression

    Directory of Open Access Journals (Sweden)

    Pang B

    2012-02-01

    Full Text Available Wencai Xu1, Teng Luo2, Ping Li1, Chuanqing Zhou2, Daxiang Cui3, Bo Pang4, Qiushi Ren4, Shen Fu11Department of Radiation Oncology, Shanghai Sixth People's Hospital, 2School of Biomedical Engineering, and 3National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Institute of Micro-Nano Science and Technology, Shanghai Jiao Tong University, Shanghai, 4Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, People's Republic of ChinaBackground: Melanoma is known to be radioresistant and traditional treatments have been intractable. Therefore, novel approaches are required to improve the therapeutic efficacy of melanoma treatment. In our study, gold nanorods conjugated with Arg-Gly-Asp peptides (RGD-GNRs were used as a sensitizer to enhance the response of melanoma cells to 6 mV radiation.Methods and materials: A375 melanoma cells were treated by gold nanorods or RGD-GNRs with or without irradiation. The antiproliferative impact of the treatments was measured by MTT assay. Radiosensitizing effects were determined by colony formation assay. Apoptosis and cell cycle data were measured by flow cytometry. Integrin αvβ3expression was also investigated by flow cytometry.Results: Addition of RGD-GNRs enhanced the radiosensitivity of A375 cells with a dose-modifying factor of 1.35, and enhanced radiation-induced apoptosis. DNA flow cytometric analysis indicated that RGD-GNRs plus irradiation induced significant G2/M phase arrest in A375 cells. Both spontaneous and radiation-induced expressions of integrin αvβ3 were downregulated by RGD-GNRs.Conclusion: Our study indicated that RGD-GNRs could sensitize melanoma A375 cells to irradiation. It was hypothesized that this was mainly through downregulation of radiation-induced αvβ3, in addition to induction of a higher proportion of cells within the G2/M phase. The combination of RGD-GNRs and

  7. "Spider"-shaped porphyrins with conjugated pyridyl anchoring groups as efficient sensitizers for dye-sensitized solar cells.

    Science.gov (United States)

    Stangel, Christina; Bagaki, Anthi; Angaridis, Panagiotis A; Charalambidis, Georgios; Sharma, Ganesh D; Coutsolelos, Athanasios G

    2014-11-17

    Two novel "spider-shaped" porphyrins, meso-tetraaryl-substituted 1PV-Por and zinc-metalated 1PV-Zn-Por, bearing four oligo(p-phenylenevinylene) (oPPV) pyridyl groups with long dodecyloxy chains on the phenyl groups, have been synthesized. The presence of four pyridyl groups in both porphyrins, which allow them to act as anchoring groups upon coordination to various Lewis acid sites, the conjugated oPPV bridges, which offer the possibility of electronic communication between the porphyrin core and the pyridyl groups, and the dodecyloxy groups, which offer the advantage of high solubility in a variety of organic solvents of different polarities and could prevent porphyrin aggregation, renders porphyrins 1PV-Por and 1PV-Zn-Por very promising sensitizers for dye-sensitized solar cells (DSSCs). Photophysical measurements, together with electrochemistry experiments and density functional theory calculations, suggest that both porphyrins have frontier molecular orbital energy levels that favor electron injection and dye regeneration in DSSCs. Solar cells sensitized by 1PV-Por and 1PV-Zn-Por were fabricated, and it was found that they show power conversion efficiencies (PCEs) of 3.28 and 5.12%, respectively. Photovoltaic measurements (J-V curves) together with incident photon-to-electron conversion efficiency spectra of the two cells reveal that the higher PCE value of the DSSC based on 1PV-Zn-Por is ascribed to higher short-circuit current (Jsc), open-circuit voltage (Voc), and dye loading values. Emission spectra and electrochemistry experiments suggest a greater driving force for injection of the photogenerated electrons into the TiO2 conduction band for 1PV-Zn-Por rather than its free-base analogue. Furthermore, electrochemical impedance spectroscopy measurements prove that the utilization of 1PV-Zn-Por as a sensitizer offers a high charge recombination resistance and, therefore, leads to a longer electron lifetime.

  8. Gadolinium texaphyrin (Gd-Tex)-malonato-platinum conjugates: synthesis and comparison with carboplatin in normal and Pt-resistant cell lines.

    Science.gov (United States)

    Arambula, Jonathan F; Sessler, Jonathan L; Fountain, Mark E; Wei, Wen-hao; Magda, Darren; Siddik, Zahid H

    2009-12-28

    The synthesis of a new PEG-solubilized gadolinium texaphyrin (Gd-Tex) conjugate containing a malonate-Pt(NH(3))(2) moiety is described. The effect of the tumor localizing Gd-Tex macrocycle on platinum activity was evaluated in cell culture. The malonate moiety, analogous to that present in carboplatin, is expected to release an aquated Pt(NH(3))(2) species under physiological conditions. The half-life in phosphate-buffered saline was found to be ca. 3 days at room temperature, and the hydrolytic product released from the conjugate was collected and confirmed as Pt-based by flameless atomic absorption spectrophotometry. Anti-proliferative activity was tested using A549 human lung cancer and A2780 human ovarian cancer cell lines. In both cell lines, the activity of the Gd-Tex conjugate was found to be similar to that of carboplatin. Efficacy against a Pt-resistant ovarian cell line greater than that displayed by carboplatin was also observed.

  9. Photovoltaic Cells with TiO2 Nanocrystals and Conjugated Polymer Composites

    Institute of Scientific and Technical Information of China (English)

    YU Huang-Zhong; LIU Jin-Cheng; PENG Jun-Biao

    2008-01-01

    @@ Various compositional photovoltaic cells based on the blend of poly(3-hexylthiophene) (P3HT) as donors and TiO2 nanoerystals as acceptors are fabricated and investigated. It is demonstrated that the blend ratio of P3HT and TiO2 nanocrystals could greatly influence the performance of the photovoltaic cells. The maximum of 0.411% in power conversion efficiency under AM 1.5, 100mW//cm2, and 44.4% of fill factor are obtained in the solar cell with the blend weight ratio 1:1 of P3HT and TiO2 nanocrystals. The function of nanocrystal composition is discussed in terms of the results of photoluminescence spectroscopy, atomic force microscopy, transmission electron microscopy, and charge transport Ⅰ-Ⅴ curve.

  10. Dye-sensitized solar cells based on porous conjugated polymer counter electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Torabi, Naeimeh; Behjat, Abbas, E-mail: abehjat@yazd.ac.ir; Jafari, Fatemeh

    2014-12-31

    In this paper, we report platinum-free dye-sensitized solar cells that were fabricated using a grown porous poly-3-methyl-thiophene (P3MT) counter electrode. The growing of the porous P3MT was performed by an electrochemical deposition method. This method is easy and affordable unlike the common expensive deposition methods. The morphology of P3MT films was studied by scanning electron microscopy images. It was observed that polymer layers grown with a current density of 2 mA/cm{sup 2} have a clear porous and rough structure as compared to layers grown with a lower current density. To understand the reaction kinetics and the catalytic activities of the counter electrodes with P3MT for 3I{sup −}/I{sub 3}{sup −} redox reaction, cyclic voltammetry (CV) was performed. Based on the analysis of CV, it was shown that this layer can be used as a counter electrode for dye-sensitized solar cells. The electro deposition conditions during the growth of polymer layers such as current density, the morphology of polymer films and the duration of polymerization have a significant role in the current–voltage characterization of the fabricated solar cells. The performance of the fabricated solar cells was improved by optimization of these parameters. The highest efficiency of 2.76% was obtained by using porous P3MT in the counter electrode. - Highlights: • Poly-3-methyl-thiophene (P3MT) layers were grown using electrochemical deposition method. • By controlling the growth conditions, porous P3MT can be produced. • Grown P3MT layers can be used as counter electrodes in dye-sensitized solar cells. • The growth rate of P3MT layers plays an essential role in the cell performance.

  11. Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and nuclear targeting in living cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fanqing; Gerion, Daniele

    2004-06-14

    One of the biggest challenges in cell biology is the imaging of living cells. For this purpose, the most commonly used visualization tool is fluorescent markers. However, conventional labels, such as organic fluorescent dyes or green fluorescent proteins (GFP), lack the photostability to allow the tracking of cellular events that happen over minutes to days. In addition, they are either toxic to cells (dyes), or difficult to construct and manipulate (GFP). We report here the use of a new class of fluorescent labels, silanized CdSe/ZnS nanocrystal-peptide conjugates, for imaging the nuclei of living cells. CdSe/ZnS nanocrystals, or so called quantum dots (qdots), are extremely photostable, and have been used extensively in cellular imaging of fixed cells. However, most of the studies about living cells so far have been concerned only with particle entry into the cytoplasm or the localization of receptors on the cell membrane. Specific targeting of qdots to the nucleus of living cells ha s not been reported in previous studies, due to the lack of a targeting mechanism and proper particle size. Here we demonstrate for the first time the construction of a CdSe/ZnS nanocrystal-peptide conjugate that carries the SV40 large T antigen nuclear localization signal (NLS), and the transfection of the complex into living cells. By a novel adaptation of commonly used cell transfection techniques for qdots, we were able to introduce and retain the NLS-qdots conjugate in living cells for up to a week without detectable negative cellular effects. Moreover, we can visualize the movement of the CdSe/ZnS nanocrystal-peptide conjugates from cytoplasm to the nucleus, and the accumulation of the complex in the cell nucleus, over a long observation time period. This report opens the door for using qdots to visualize long-term biological events that happen in the cell nucleus, and provides a new nontoxic, long-term imaging platform for cell nuclear processes.

  12. Fluorescent CdSe/ZnS Nanocrystal-Peptide Conjugates for Long-term, Nontoxic Imaging and Nuclear Targeting in Living Cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F; Gerion, D

    2004-06-08

    One of the biggest challenges in cell biology is the imaging of living cells. For this purpose, the most commonly used visualization tool is fluorescent markers. However, conventional labels, such as organic fluorescent dyes or green fluorescent proteins (GFP), lack the photostability to allow the tracking of cellular events that happen over minutes to days. In addition, they are either toxic to cells (dyes), or difficult to construct and manipulate (GFP). We report here the use of a new class of fluorescent labels, silanized CdSe/ZnS nanocrystal-peptide conjugates, for imaging the nuclei of living cells. CdSe/ZnS nanocrystals, or so called quantum dots (qdots), are extremely photostable, and have been used extensively in cellular imaging of fixed cells. Most of the studies about living cells so far have been concerned only with particle entry into the cytoplasm or the localization of receptors on the cell membrane. Specific targeting of qdots to the nucleus of living cells has not been reported in previous studies, due to the lack of a targeting mechanism and proper particle size. Here we demonstrate for the first time the construction of a CdSe/ZnS nanocrystal-peptide conjugate that carries the SV40 large T antigen nuclear localization signal (NLS), and the transfection of the complex into living cells. By a novel adaptation of a commonly used cell transfection technique for qdots, we were able to introduce and retain the NLS-qdot conjugates in living cells for up to a week without detectable negative cellular effects. Moreover, we can visualize the movement of the CdSe/ZnS qdot-peptide conjugates from cytoplasm to the nucleus, and the accumulation of the complex in the cell nucleus, over a long observation time period. This report opens the door for using qdots to visualize long-term biological events that happen in the cell nucleus, and provides a new nontoxic, long-term imaging platform for nuclear trafficking mechanisms and cell nuclear processes.

  13. Synthesis of antifungal vaccines by conjugation of β-1,2 trimannosides with T-cell peptides and covalent anchoring of neoglycopeptide to tetanus toxoid.

    Science.gov (United States)

    Cartmell, Jonathan; Paszkiewicz, Eugenia; Dziadek, Sebastian; Tam, Pui-Hang; Luu, Thanh; Sarkar, Susmita; Lipinski, Tomasz; Bundle, David R

    2015-02-11

    Selective strategies for the construction of novel three component glycoconjugate vaccines presenting Candida albicans cell wall glycan (β-1,2 mannoside) and polypeptide fragments on a tetanus toxoid carrier are described. The first of two conjugation strategies employed peptides bearing an N-terminal thiopropionyl residue for conjugation to a trisaccharide equipped with an acrylate linker and a C-terminal S-acetyl thioglycolyl moiety for subsequent linking of neoglycopeptide to bromoacetylated tetanus toxoid. Michael addition of acrylate trisaccharides to peptide thiol under mildly basic conditions gave a mixture of N- and C- terminal glyco-peptide thioethers. An adaptation of this strategy coordinated S-acyl protection with anticipated thioester exchange equilibria. This furnished a single chemically defined fully synthetic neoglycopeptide conjugate that could be anchored to a tetanus toxoid carrier and avoids the introduction of exogenous antigenic groups. The second strategy retained the N-terminal thiopropionyl residue but replaced the C-terminal S-acetate functionality with an azido group that allowed efficient, selective formation of neoglycopeptide thioethers and subsequent conjugation of these with propargylated tetanus toxoid, but introduced potentially antigenic triazole linkages.

  14. Nature of the Binding Interactions between Conjugated Polymer Chains and Fullerenes in Bulk Heterojunction Organic Solar Cells

    KAUST Repository

    Ravva, Mahesh Kumar

    2016-10-24

    Blends of π-conjugated polymers and fullerene derivatives are ubiquitous as the active layers of organic solar cells. However, a detailed understanding of the weak noncovalent interactions at the molecular level between the polymer chains and fullerenes is still lacking and could help in the design of more efficient photoactive layers. Here, using a combination of long-range corrected density functional theory calculations and molecular dynamic simulations, we report a thorough characterization of the nature of binding between fullerenes (C60 and PC61BM) and poly(benzo[1,2-b:4,5-b′]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) chains. We illustrate the variations in binding strength when the fullerenes dock on the electron-rich vs electron-poor units of the polymer as well as the importance of the role played by the polymer and fullerene side chains and the orientations of the PC61BM molecules with respect to the polymer backbones.

  15. Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells.

    Science.gov (United States)

    Chen, Weichao; Xiao, Manjun; Han, Liangliang; Zhang, Jidong; Jiang, Huanxiang; Gu, Chuantao; Shen, Wenfei; Yang, Renqiang

    2016-08-03

    Unsubstituted benzo[1,2-b:4,5-b']dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (-5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm(2) V(-1) s(-1). Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC71BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm(-2)) and high fill factor (0.751) without any process additives or thermal annealing.

  16. Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Biancardo, M.

    2006-01-01

    and the complex was adsorbed onto the surface before evaporation of gold electrodes. Alternative devices were obtained by spincoating of the polymer solution onto PEDOT:PSS covered indium-doped tin oxide substrates. PEC solar cells gave the best results and the main finding was that the polymer chain served...

  17. Synthesis and biological evaluation of salicylic acid conjugated isoxazoline analogues on immune cell proliferation and angiogenesis.

    Science.gov (United States)

    Puttaswamy, Naveen; Pavan Kumar, G S; Al-Ghorbani, Mohammed; Vigneshwaran, V; Prabhakar, B T; Khanum, Shaukath Ara

    2016-05-23

    Mitogenicity is the ability of the natural or synthetic compounds to induce cell division or proliferation. A series of salicylic acid derivatives containing isoxazoline moiety (8a-j) were synthesized and their immunopharmacological activities targeting lymphocyte proliferation and angiogenesis were evaluated. The compounds 8a-j mitogenicity were investigated on immunological cells that include human peripheral blood lymphocytes and murine splenocytes in-vitro. The results implicate that among the series of 8a-j, compound 8e showed a potent proliferative response on both human and murine lymphocytes. The proliferative index of the compound 8e was comparable to the reference mitogen Con A and mitogenecity is due to increased secretion IL-2. In -vivo CAM and rat corneal angiogenesis assays were performed to assess the compound's effect on endothelial cell migration and proliferation which inferred that 8e also induces the proliferation of endothelial cells. The study reports the synthetic immunostimulatory and pro-angiogenic activity of novel mitogen 8e which could be translated into new drug in future.

  18. Thermo-cleavable solvents for printing conjugated polymers: Application in polymer solar cells

    DEFF Research Database (Denmark)

    Jørgensen, Mikkel; Hagemann, Ole; Alstrup, Jan

    2009-01-01

    The synthesis and characterization of a number of so-called thermo-cleavable solvents are described with their application in all-air, all-solution and all-screen-printed polymer solar cells. These solvents were developed to meet some requirements for printing techniques such as long “open time...

  19. Diethylentriaminepenta acetic acid glucose conjugates as a cell permeable iron chelator

    Directory of Open Access Journals (Sweden)

    Mona Mosayebnia

    2014-01-01

    Full Text Available Objective: To find out whether DTPA-DG complex can enhance clearance of intracellular free iron. Materials and Methods: Diethylenetriaminepentaacetic acid-D-deoxy-glucosamine (DTPA-DG was synthesized and examined for its activity as a cell-permeable iron chelator in human hepatocellular carcinoma (HEPG2 cell line exposed to high concentration of iron sulfate and compared with deferoxamine (DFO, a prototype iron chelator. The effect of DTPA-DG on cell viability was monitored using the 3-(4,5-dimethythiazol-2-yl-2,5-diphenyl tetrazolium bromide MTT assay as well. Results: There was a significant increase of iron level after iron overload induction in HEPG2 cell culture. DTPA-DG presented a remarkable capacity to iron burden reducing with estimated 50% inhibitory concentration value of 65.77 nM. In fact, glycosyl moiety was gained access of DTPA to intracellular iron deposits through glucose transporter systems. Conclusion: DTPA-DG, more potent than DFO to sequester deposits of free iron with no profound toxic effect. The results suggest the potential of DTPA-DG in chelating iron and permitting its excretion from primary organ storage.

  20. Stability and photodegradation mechanisms of conjugated polymer/fullerene plastic solar cells

    NARCIS (Netherlands)

    Neugebauer, H.; Brabec, C.; Hummelen, J.C.; Sariciftci, N.S.

    2000-01-01

    Degradation studies of poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene-vinylene) (MDMO-PPV), fullerenes ((6,6)-phenyl C-61-butyric acid methyl ester (PCBM) and C-60), and mixtures, which are the photoactive components in plastic solar cells, are shown. The degradation processes of the indivi

  1. The Presence of Conjugative Plasmid pLS20 Affects Global Transcription of Its Bacillus subtilis Host and Confers Beneficial Stress Resistance to Cells

    Science.gov (United States)

    Rösch, Thomas C.; Golman, Wladislaw; Hucklesby, Laura; Gonzalez-Pastor, Jose E.

    2014-01-01

    Conjugation activity of plasmid pLS20 from Bacillus subtilis subsp. natto is induced when cells are diluted into fresh medium and diminishes as cells enter into stationary-phase growth. Transcriptional profiling shows that during mid-exponential growth, more than 5% of the host genes are affected in the presence of the plasmid, in contrast to the minor changes seen in freshly diluted and stationary-phase cells. Changes occurred in many metabolic pathways, although pLS20 does not confer any detectable burden on its host cell, as well as in membrane and cell wall-associated processes, in the large motility operon, and in several other cellular processes. In agreement with these changes, we found considerable alterations in motility and enzyme activity and increased resistance against several different forms of stress in cells containing the plasmid, revealing that the presence of pLS20 has a broad impact on the physiology of its host cell and increases its stress resistance in multiple aspects. Additionally, we found that the lack of chromosomal gene yueB, known to encode a phage receptor protein, which is upregulated in cells containing pLS20, strongly reduced conjugation efficiency, revealing that pLS20 not only increases fitness of its host but also employs host proteins for efficient transfer into a new cell. PMID:24334659

  2. Enhanced delivery of Paclitaxel using electrostatically-conjugated Herceptin-bearing PEI/PLGA nanoparticles against HER-positive breast cancer cells.

    Science.gov (United States)

    Yu, Kongtong; Zhao, Jinlong; Zhang, Zunkai; Gao, Yin; Zhou, Yulin; Teng, Lesheng; Li, Youxin

    2016-01-30

    We have developed a novel nanoparticle delivery system fabricated from polyethylenimine (PEI) and poly(d,l-lactide-co-glycolide) (PLGA), which were able to deliver the chemotherapeutic agent Paclitaxel, while the biomacromolecule Herceptin acted as a targeting ligand that was conjugated onto the surfaces of the nanoparticles via electrostatic interactions. In this study, these electrostatically-conjugated Herceptin-bearing PEI/PLGA nanoparticles (eHER-PPNs) were optimized and employed as vectors to target HER2-positive breast cancer cells. The eHER-PPNs had an average diameter of ∼ 280 nm and a neutral surface charge (1.00 ± 0.73 mV), which remained stable under physiological conditions. The anticancer effects of eHER-PPNs were investigated in HER2-positive BT474 cells and HER2-negative MCF7 cells. The eHER-PPNs showed enhanced cytotoxicity that was dependent on the receptor expression levels and the incubation time. These conjugated nanoparticles deliver Paclitaxel more efficiently (pHerceptin and the combined effects of these two monotherapies. Furthermore, the chemically-conjugated Herceptin-bearing PEI/PLGA nanoparticles (cHER-PPNs) were fabricated as a comparison. The eHER-PPNs exhibited lower cell viability (46.7%) than that of cHER-PPNs (65.1%). The targeting ability of eHER-PPNs was demonstrated through confocal microscopy images and flow cytometry, which showed that eHER-PPNs displayed higher cellular uptake efficiency (p<0.001) in comparison with cHER-PPNs. Therefore, eHER-PPNs could provide promising platforms for the delivery of therapeutic drugs against HER2-positive breast cancers.

  3. Fluoridated hydroxyapatite: Eu3+ nanorods-loaded folate-conjugated D-α-tocopheryl polyethylene glycol succinate (vitamin E TPGS) micelles for targeted imaging of cancer cells

    Science.gov (United States)

    Wan, Dong; Liu, Weijiao; Wang, Lei; Wang, Hao; Pan, Jie

    2016-03-01

    In this study, fluoridated hydroxyapatite: Eu3+ nanorod-loaded folate-conjugated TPGS micelles were prepared by thin-film hydration. The findings in this study demonstrate that micelles show improved dispersion, high stability, and excellent fluorescent property in aqueous solutions, suitable for targeted imaging of cancer cells with over-expressing folate receptors on their surface. The micelles designed in this study will be a promising tool for early detection of cancer.

  4. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    DEFF Research Database (Denmark)

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm

    2013-01-01

    Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted...... towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor...... to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient...

  5. Polyimidazole conjugated oligonucleotides reach the nucleus of HeLa cells.

    Science.gov (United States)

    Morvan, F; Castex, C; Vivès, E; Imbach, J L

    2001-01-01

    Oligonucleotide models bearing 6, 12 or 18 histamine residues were synthesized on solid support and labeled with fluorescein. Only the oligo with 6 histamine residues showed a high uptake in HeLa cells with a nuclear localization. Experiment a 4 degrees C or with bafilomicyn A1 suggest that uptake proceeded by an endocytosis mechanism followed by a destabilization of the membrane. Once in the cytoplasm the oligo reached rapidly the nucleus.

  6. Ultrafast optical measurements of charge generation and transfer mechanisms of pi-conjugated polymers for solar cell applications

    Science.gov (United States)

    Holt, Joshua Michael

    Current developments in organic solar cells based on donor-acceptor blends require understanding and control of photoinduced charge transfer and electronic state dynamics. In this work the ultrafast dynamics of photoexcitations in pi-conjugated organic semiconductors were studied using a low-intensity, high-repetition rate laser system in the broad mid- to near-infrared (IR) spectral range from 0.25 to 1.1 eV, and a high-intensity, low-repetition rate laser system in the spectral range from 1.2 to 2.5 eV, in the time domain up to 1 ns with 150 fs resolution. We also applied CW photomodulation spectroscopy along with excitation spectrum, modulation frequency sweeps, photoluminescence and electroabsorption to study the excited states of pi-conjugated polymers and acceptor-donor blends. One current drawback to organic solar cell efficiency is negligible absorption in the near infrared spectral range of the solar spectrum. We provide and compare evidence that poly(2-methoxy-5(2'-ethyl)hexoxy-phenylenevinylene) (MEH-PPV) [electron donor] blended with 2,4,7-trinitrofluorenone (TNF) [strong electron acceptor] form a below-gap charge transfer complex (CTC) state that can extend absorption into the near infrared. The transient PA measurements also show that significant charge species are initially photogenerated, a majority of which geminately recombine within 8-10 ps, but the few that escape geminate recombination are subsequently captured in long-lived traps. In addition polarons could be also photogenerated with high efficiency at near-IR excitation, with similar fate. This demonstrates that a CTC state exists below the MEH-PPV polymer optical gap, but with low dissociation efficiency. We compare our results to those in blends of MEH-PPV/C60 where apparently a charge transport pathway to the electrodes is formed and the obtained CTC state has higher dissociation efficiency. The most efficient all-organic photovoltaic (OPV) cells to date (˜6% power conversion efficiency

  7. Potent inhibitory effect of trans9, trans11 isomer of conjugated linoleic acid on the growth of human colon cancer cells

    OpenAIRE

    Beppu, Fumiaki; Hosokawa, Masashi; Tanaka, Leo; Kohno, Hiroyuki; Tanaka, Takuji; Miyashita, Kazuo

    2006-01-01

    This study compared the growth inhibitory effects of pure conjugated linoleic acid (CLA) isomers [cis(c)9,c11-CLA, c9,trans(t)11-CLA, t9,t11-CLA, and t10,c12-CLA] on human colon cancer cell lines (Caco-2, HT-29 and DLD-1). When Caco-2 cells were incubated up to 72 h with 200 μM, each isomer, even in the presence of 10% fetal bovine serum (FBS), cell proliferation was inhibited by all CLA isomers in a time-dependent manner. The strongest inhibitory effect was shown by t9,t11-CLA, followed by t...

  8. Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying, E-mail: caoying1130@sina.com [Henan Normal University, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Chemical Engineering (China)

    2013-11-15

    Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

  9. Folate-conjugated polymer micelles for active targeting to cancer cells: preparation, in vitro evaluation of targeting ability and cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    You Jian [College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058 (China); Li Xin [College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058 (China); Cui Fude [College of Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016 (China); Du Yongzhong [College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058 (China); Yuan Hong [College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058 (China); Hu Fuqiang [College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058 (China)

    2008-01-30

    To obtain an active-targeting carrier to cancer cells, folate-conjugated stearic acid grafted chitosan oligosaccharide (Fa-CSOSA) was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The substitution degree is 22.1%. The critical micelle concentrations (CMCs) of Fa-CSOSA were 0.017 and 0.0074 mg ml{sup -1} in distilled water and PBS (pH 7.4), respectively. The average volume size range of Fa-CSOSA micelles was 60-120 nm. The targeting ability of Fa-CSOSA micelles was investigated against two kinds of cell lines (A549 and Hela), which have different amounts of folate receptors in their surface. The results indicated that Fa-CSOSA micelles presented a targeting ability to the cells (Hela) with a higher expression of folate receptor during a short-time incubation (<6 h). As incubation proceeded, the special spatial structure of the micelles gradually plays a main role in cellular internalization of the micelles. Good internalization of the micelles into both Hela and A549 cells was shown. Then, paclitaxel (PTX) was encapsulated into the micelles, and the content of PTX in the micelles was about 4.8% (w/w). The average volume size range of PTX-loaded micelles was 150-340 nm. Furthermore, the anti-tumor efficacy in vitro was investigated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) method. The IC{sub 50} of Taxol (a clinical formulation containing PTX) on A549 and Hela cells was 7.0 and 11.0 {mu}g ml{sup -1}, respectively. The cytotoxicity of PTX-loaded micelles was improved sharply (IC{sub 50} on A549: 0.32 {mu}g ml{sup -1}; IC{sub 50} on Hela: 0.268 {mu}g ml{sup -1}). This is attributed to the increased intracellular delivery of the drug. The Fa-CSOSA micelles that are presented may be a promising active-targeting carrier candidate via folate mediation.

  10. A three-dimensional tetrahedral-shaped conjugated small molecule for organic solar cells

    Directory of Open Access Journals (Sweden)

    QIN Yang

    2014-04-01

    Full Text Available We report the synthesis of a novel three-dimensional tetrahedral-shaped small molecule,SO,containing a tetraphenylsilane core and cyanoester functionalized terthiophene arms.A deep lying HOMO energy level of -5.3 eV and a narrow bandgap of 1.9 eV were obtained from cyclic voltammetry measurements.Absorption,X-ray scattering and differential scanning calorimetry experiments all indicate high crystallinity of this compound.Solar cells employing SO were fabricated and evaluated.The relatively low performance was mainly ascribed to lack of appreciable phase separation,which is confirmed by optical microscopy.

  11. Tellurium-Containing Conjugated Materials for Solar Cells: From Sulfur to Tellurium

    Energy Technology Data Exchange (ETDEWEB)

    Park Y. S.; Kale, T.; Wu, Q.; Ocko, B.M.; Black, C.T., Grubbs, R.B.

    2013-04-03

    A series of diketopyrrolopyrrole(DPP)-based small molecules have been synthesized by palladium-catalyzed coupling reactions. Electron-donating moieties (benzothiophene, benzoselenophene, and benzotellurophene) are bridged by an electron-withdrawing DPP unit to generate donor-acceptor-donor (D-A-D) type molecules. We observe red-shifts in absorption spectra of these compounds by varying heteroatoms from sulfur to tellurium. In bulk heterojunction solar cells with [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) as acceptor, we obtain power conversion efficiencies of 2.4% (benzothiophene), 4.1% (benzoselenophene), and 3.0% (benzotellurophene), respectively.

  12. Synthesis of AS1411-aptamer-conjugated CdTe quantum dots with high fluorescence strength for probe labeling tumor cells.

    Science.gov (United States)

    Alibolandi, Mona; Abnous, Khalil; Ramezani, Mohammad; Hosseinkhani, Hossein; Hadizadeh, Farzin

    2014-09-01

    In this paper, we report microwave-assisted, one-stage synthesis of high-quality functionalized water-soluble cadmium telluride (CdTe) quantum dots (QDs). By selecting sodium tellurite as the Te source, cadmium chloride as the Cd source, mercaptosuccinic acid (MSA) as the capping agent, and a borate-acetic acid buffer solution with a pH range of 5-8, CdTe nanocrystals with four colors (blue to orange) were conveniently prepared at 100 °C under microwave irradiation in less than one hour (reaction time: 10-60 min). The influence of parameters such as the pH, Cd:Te molar ratio, and reaction time on the emission range and quantum yield percentage (QY%) was investigated. The structures and compositions of the prepared CdTe QDs were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and X-ray powder diffraction experiments. The formation mechanism of the QDs is discussed in this paper. Furthermore, AS1141-aptamer-conjugated CdTe QDs in the U87MG glioblastoma cell line were assessed with a fluorescence microscope. The obtained results showed that the best conditions for obtaining a high QY of approximately 87% are a pH of 6, a Cd:Te molar ratio of 5:1, and a 30-min reaction time at 100 °C under microwave irradiation. The results showed that AS1141-aptamer-conjugated CdTe QDs could enter tumor cells efficiently. It could be concluded that a facile high-fluorescence-strength QD conjugated with a DNA aptamer, AS1411, which can recognize the extracellular matrix protein nucleolin, can specifically target U87MG human glioblastoma cells. The qualified AS1411-aptamer-conjugated QDs prepared in this study showed excellent capabilities as nanoprobes for cancer targeting and molecular imaging.

  13. Optical properties of a conjugated-polymer-sensitised solar cell: the effect of interfacial structure.

    Science.gov (United States)

    Drumm, Daniel W; Bilic, A; Tachibana, Y; Miller, A; Russo, S P

    2015-06-14

    Dye-sensitised solar cells (DSSCs) have sparked considerable interest over two decades. Recently, a method of polymer-wire sensitisation was demonstrated; the polymer is suggested to form a hole transport pathway (wire) following initial charge separation. We predict the optical properties of this polymer in various interfacial configurations, including the effects of chain length and attachment to {100} or {101} TiO2 facets. Contrary to most DSSCs, the {100} facet model best describes the experimental spectrum, predicting a relative thickness of 5.7 ± 0.2 μm, although {101} attachment, if implemented, may improve collection efficiency. Long chains are optimal, and stable attachment sites show minimal differences to absorbance in the major solar emission (visible) band. Combinations of {100}, {101}, and pseudo-bulk TiO2 models in three-parameter fits to experiment confirm the relative importance of the {100} facet.

  14. Energy change in the formation of conjugated bilirubin: A possible responsive mechanism for liver cell pathology Cambio energético durante la conjugación de la bilirrubina: un posible mecanismo de lesión hepatocelular

    Directory of Open Access Journals (Sweden)

    V. Wiwanitkit

    2007-02-01

    Full Text Available Bilirubin is formed when red blood cells die and their hemoglobin is broken down within the macrophages into heme and globins. In the liver, bilirubin is conjugated with UDP-glucuronate, making it water-soluble diglucuronide. Concerning this conjugation, a molecule of bilirubin reacts with two molecules of glucoronic acid. However, the nature of this energy-consuming reaction in the formation of conjugated bilirubin has never been reported, and this can be important for its potential implication in hyperbilirubinemia. In this work, the author calculated the energy required by conjugated-bilirubin formation per molecule. The energy required for complex formation is -22 kCal/mol. The nature of this energy-producing reaction can be a good explanation. Increased energy delivery in conjugated hyperbilirubinemia in liver disease might be a responsive mechanism to hepatic damage.

  15. Elimination of Tumor Cells Using Folate Receptor Targeting by Antibody-Conjugated, Gold-Coated Magnetite Nanoparticles in a Murine Breast Cancer Model

    Directory of Open Access Journals (Sweden)

    Evan S. Krystofiak

    2012-01-01

    Full Text Available Background. The chemotherapeutic treatment of cancer suffers from poor specificity for targeting the tumor cells and often results in adverse effects such as systemic toxicity, damage to nontarget tissues, and development of drug-resistant tumors in patients. Increasingly, drug nanocarriers have been explored as a way of lessening or overcoming these problems. In this study, antibody-conjugated Au-coated magnetite nanoparticles, in conjunction with inductive heating produced by exposure to an oscillating magnetic field (OMF, were evaluated for their effects on the viability of tumor cells in a murine model of breast cancer. Treatment effects were evaluated by light microscopy and SEM. Results. 4T1 mammary epithelial carcinoma cells overexpressing the folate receptor were targeted with an anti-folate receptor primary antibody, followed by labeling with secondary antibody-conjugated Au-coated magnetite nanoparticles. In the absence of OMF exposure, nanoparticle labeling had no effect on 4T1 cell viability. However, following OMF treatment, many of the labeled 4T1 cells showed extensive membrane damage by SEM analysis, and dramatically reduced viability as assessed using a live/dead staining assay. Conclusions. These results demonstrate that Au-coated magnetite targeted to tumor cells through binding to an overexpressed surface receptor, in the presence of an OMF, can lead to tumor cell death.

  16. The sentrin-conjugating enzyme mUbc9 interacts with GLUT4 and GLUT1 glucose transporters and regulates transporter levels in skeletal muscle cells

    Science.gov (United States)

    Giorgino, Francesco; de Robertis, Ottilia; Laviola, Luigi; Montrone, Carmela; Perrini, Sebastio; McCowen, Karen C.; Smith, Robert J.

    2000-01-01

    Glucose transport in insulin-regulated tissues is mediated by the GLUT4 and GLUT1 transporters. Using the yeast two-hybrid system, we have cloned the sentrin-conjugating enzyme mUbc9 as a protein that interacts with the GLUT4 COOH-terminal intracellular domain. The mUbc9 enzyme was found to bind directly to GLUT4 and GLUT1 through an 11-aa sequence common to the two transporters and to modify both transporters covalently by conjugation with the mUbc9 substrate, sentrin. Overexpression of mUbc9 in L6 skeletal muscle cells decreased GLUT1 transporter abundance 65%, resulting in decreased basal glucose transport. By contrast, mUbc9 overexpression increased GLUT4 abundance 8-fold, leading to enhanced transport stimulation by insulin. A dominant-negative mUbc9 mutant lacking catalytic activity had effects opposite to those of wild-type mUbc9. The regulation of GLUT4 and GLUT1 was specific, as evidenced by an absence of mUbc9 interaction with or regulation of the GLUT3 transporter isoform in L6 skeletal muscle cells. The mUbc9 sentrin-conjugating enzyme represents a novel regulator of GLUT1 and GLUT4 protein levels with potential importance as a determinant of basal and insulin-stimulated glucose uptake in normal and pathophysiological states. PMID:10655495

  17. Cancer Cell Targeting Using Folic Acid/Anti-HER2 Antibody Conjugated Fluorescent CdSe/CdS/ZnS-MPA and CdTe-MSA Quantum Dots.

    Science.gov (United States)

    Singh, Gurpal; Kumar, Manoj; Soni, Udit; Arora, Vikas; Bansal, Vivek; Gupta, Dikshi; Bhat, Madhusudan; Dinda, Amit K; Sapra, Sameer; Singh, Harpal

    2015-12-01

    CdSe/CdS/ZnS and CdTe quantum dots (QDs) were synthesized by successive ion layer adsorption and reaction (SILAR) technique and direct aqueous synthesis respectively using thiol stabilizers. Synthesized CdSe/CdS/ZnS and CdTe QDs stabilized with 3-mercaptopropionic acid (MPA) and mercaptosuccinic acid (MSA) were used as fluorescent labels after conjugation with folic acid (FA) and anti-HER2 antibodies. Photoluminescence quantum yield of folated CdSe/CdS/ZnS-MPA and CdTe-MSA QDs was 59% and 77% than that of non-folated hydrophilic QDs. The folate receptor-mediated delivery of folic acid-conjugated CdTe-MSA and CdSe/CdS/ZnS-MPA QDs showed higher cellular internalization as observed by confocal laser scanning microscopic studies. Folated and non-folated CdTe-MSA QDs were highly toxic and exhibited only 10% cell viability as compared to > 80% cell viability with CdSe/CdS/ZnS-MPA QDs over the concentration ranging from 3.38 to 50 pmoles. Immunohistochemistry (IHC) results of human breast cancer tissue samples showed positive results with anti-HER2 antibody conjugated CdSe/CdS/ZnS-MPA QDs with better sensitivity and specificity as compared to conventional IHC analysis using diaminobenzedene staining.

  18. Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells.

    Science.gov (United States)

    Komiyama, Hideaki; Adachi, Chihaya; Yasuda, Takuma

    2016-01-01

    Solution-processable star-shaped and linear π-conjugated oligomers consisting of an electron-donating tetrathienoanthracene (TTA) core and electron-accepting diketopyrrolopyrrole (DPP) arms, namely, TTA-DPP4 and TTA-DPP2, were designed and synthesized. Based on density functional theory calculations, the star-shaped TTA-DPP4 has a larger oscillator strength than the linear TTA-DPP2, and consequently, better photoabsorption property over a wide range of visible wavelengths. The photovoltaic properties of organic solar cells based on TTA-DPP4 and TTA-DPP2 with a fullerene derivative were evaluated by varying the thickness of the bulk heterojunction active layer. As a result of the enhanced visible absorption properties of the star-shaped π-conjugated structure, better photovoltaic performances were obtained with relatively thin active layers (40-60 nm).

  19. Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

    Science.gov (United States)

    Adachi, Chihaya

    2016-01-01

    Summary Solution-processable star-shaped and linear π-conjugated oligomers consisting of an electron-donating tetrathienoanthracene (TTA) core and electron-accepting diketopyrrolopyrrole (DPP) arms, namely, TTA-DPP4 and TTA-DPP2, were designed and synthesized. Based on density functional theory calculations, the star-shaped TTA-DPP4 has a larger oscillator strength than the linear TTA-DPP2, and consequently, better photoabsorption property over a wide range of visible wavelengths. The photovoltaic properties of organic solar cells based on TTA-DPP4 and TTA-DPP2 with a fullerene derivative were evaluated by varying the thickness of the bulk heterojunction active layer. As a result of the enhanced visible absorption properties of the star-shaped π-conjugated structure, better photovoltaic performances were obtained with relatively thin active layers (40–60 nm). PMID:27559398

  20. CdTe/CdS-MPA quantum dots as fluorescent probes to label yeast cells: synthesis, characterization and conjugation with Concanavalin A

    Science.gov (United States)

    Kato, Ilka T.; Santos, Camila C.; Benetti, Endi; Tenório, Denise P. L. A.; Cabral Filho, Paulo E.; Sabino, Caetano P.; Fontes, Adriana; Santos, Beate S.; Prates, Renato A.; Ribeiro, Martha S.

    2012-03-01

    Candida albicans is the most frequent human opportunistic pathogenic fungus and one of the most important causes of nosocomial infections. In fact, diagnosis of invasive candidiasis presents unique problems. The aim of this work was to evaluate, by fluorescence image analysis, cellular labeling of C. albicans with CdTe/CdS quantum dots conjugated or not to concanavalin A (ConA). Yeast cells were incubated with CdTe/CdS quantum dots (QD) stabilized with mercaptopropionic acid (MPA) (emission peak at 530 nm) for 1 hour. In the overall study we observed no morphological alterations. The fluorescence microscopic analysis of the yeast cells showed that the non-functionalized QDs do not label C. albicans cells, while for the QD conjugated to ConA the cells showed a fluorescence profile indicating that the membrane was preferentially marked. This profile was expected since Concanavalin A is a protein that binds specifically to terminal carbohydrate residues at the membrane cell surface. The results suggest that the QD-labeled Candida cells represent a promising tool to open new possibilities for a precise evaluation of fungal infections in pathological conditions.

  1. Melphalan, alone or conjugated to an FSH-β peptide, kills murine testicular cells in vitro and transiently suppresses murine spermatogenesis in vivo.

    Science.gov (United States)

    Amory, John K; Hong, SungWoo; Yu, Xiaozhong; Muller, Charles H; Faustman, Elaine; Goldstein, Alex

    2014-07-01

    New approaches to sterilizing male animals are needed to control captive and wild animal populations. We sought to develop a nonsurgical method of permanent sterilization for male animals by administering the gonadotoxicant melphalan conjugated to peptides derived from the β-chain of FSHβ. We hypothesized that conjugating melphalan to FSHβ peptides would magnify the gonadotoxic effects of melphalan while minimizing systemic toxicity. The ability of conjugates of melphalan and FSHβ peptides to kill murine testicular cells was first tested in vitro in a three-dimensional testicular cell coculture system. In this system, melphalan caused considerable cell death as measured both by increases in lactate dehydrogenase concentrations in the culture supernatant and direct visualization of the cultures. Of the conjugates tested, melphalan conjugated to a 20-amino acid peptide derived from human FSHβ consisting of amino acids 33 to 53 (FSHβ (33-53)-melphalan) was very potent, with cell cytotoxicity and lactate dehydrogenase release roughly one-half that of melphalan. The effects of melphalan and FSHβ (33-53)-melphalan on spermatogenesis were then tested in vivo in mature C56Bl/6 male mice. Four weeks after intraperitoneal injection, all mice treated with either FSHβ (33-53)-melphalan or melphalan had approximately 75% reductions in testicular spermatid counts compared with control animals. Testicular histology revealed significant reduction in mature spermatids and spermatocytes in most tubules. However, 12 weeks after the injection, testicular spermatid counts and histology were similar to controls, except in one animal receiving FSHβ (33-53)-melphalan that had no apparent spermatogenesis. We conclude that melphalan and FSHβ (33-53)-melphalan are potent gonadotoxicants in male mice resulting in marked suppression of spermatogenesis 4 weeks after a single intraperitoneal injection. However, this effect is transient in most mice as spermatogenesis is similar to

  2. Selective uptake of cylindrical poly(2-oxazoline) brush-antiDEC205 antibody-OVA antigen conjugates into DEC-positive dendritic cells and subsequent T-cell activation.

    Science.gov (United States)

    Bühler, Jasmin; Gietzen, Sabine; Reuter, Anika; Kappel, Cinja; Fischer, Karl; Decker, Sandra; Schäffel, David; Koynov, Kaloian; Bros, Matthias; Tubbe, Ingrid; Grabbe, Stephan; Schmidt, Manfred

    2014-09-22

    To achieve specific cell targeting by various receptors for oligosaccharides or antibodies, a carrier must not be taken up by any of the very many different cells and needs functional groups prone to clean conjugation chemistry to derive well-defined structures with a high biological specificity. A polymeric nanocarrier is presented that consists of a cylindrical brush polymer with poly-2-oxazoline side chains carrying an azide functional group on each of the many side chain ends. After click conjugation of dye and an anti-DEC205 antibody to the periphery of the cylindrical brush polymer, antibody-mediated specific binding and uptake into DEC205(+) -positive mouse bone marrow-derived dendritic cells (BMDC) was observed, whereas binding and uptake by DEC205(-) negative BMDC and non-DC was essentially absent. Additional conjugation of an antigen peptide yielded a multifunctional polymer structure with a much stronger antigen-specific T-cell stimulatory capacity of pretreated BMDC than application of antigen or polymer-antigen conjugate.

  3. Hybrid solar cells of conjugated polymers metal-oxide nanocrystals blends; state of the art and future research challenges in Indonesia

    Science.gov (United States)

    Bahtiar, Ayi

    2013-09-01

    Ever-increasing world energy demand, depleting non-renewable energy resources and disruptive climate change due to greenhouse gases has aroused much interest in alternative renewable energy sources. Solar energy is one of the best available alternatives, for it is both abundant and clean. Solar cell is an effective device for converting solar energy into electricity. Indonesia is located on the equator where the sunlight is always available in abundance throughout the year; therefore solar cell would become the main source of electrical energy in Indonesia. However, the high cost of inorganic solar cells in spite of their high power conversion efficiency (PCE) has been a major constrain for their mass utilization in Indonesia. The only way to reduce the cost of production and installation is to find other materials which offer low-cost and easy processing into solar cells. Polymer solar cells have been intensively investigated for high performance and low-cost solar cells. Today, 9-11% power conversion efficiency (PCE) of small area polymer solar cells and 2-4% PCE of large area or module solar cells are already achieved. However, for practical application and mass production, 10% or higher PCE of module solar cells is highly required. The main strategic issue for improving the PCE is to use blend of conjugated polymer-metal oxide nanocrystals as active materials for hybrid solar cells, due to the good combination of the versatile solution processability of conjugated polymers and high charge carrier mobility of metal-oxide nanocrystals. In this paper, current development of hybrid solar cells worldwide and future research challenges in Indonesia will be discussed.

  4. Differential neuroprotective potential of CRMP2 peptide aptamers conjugated to cationic, hydrophobic, and amphipathic cell penetrating peptides

    Directory of Open Access Journals (Sweden)

    Aubin eMoutal

    2015-01-01

    Full Text Available The microtubule-associated axonal specification collapsin response mediator protein 2 (CRMP2 is a novel target for neuroprotection. A CRMP2 peptide (TAT-CBD3 conjugated to the HIV transactivator of transcription (TAT protein’s cationic cell penetrating peptide motif (CPP protected neurons in the face of toxic levels of Ca2+ influx leaked in via N-methyl-D-aspartate receptor (NMDAR hyperactivation. Here we tested whether replacing the hydrophilic TAT motif with alternative cationic (nona-arginine (R9, hydrophobic (membrane transport sequence (MTS of k-fibroblast growth factor or amphipathic (model amphipathic peptide (MAP CPPs could be superior to the neuroprotection bestowed by TAT-CBD3. In giant plasma membrane vesicles (GPMVs derived from cortical neurons, the peptides translocated across plasma membranes with similar efficiencies. Cortical neurons, acutely treated with peptides prior to a toxic glutamate challenge, demonstrated enhanced efflux of R9-CBD3 compared to others. R9-CBD3 inhibited N-methyl-D-aspartate (NMDA-evoked Ca2+ influx to a similar extent as TAT-CBD3 while MTS-CBD3 was ineffective which correlated with the ability of R9- and TAT-CBD3, but not MTS-CBD3, to block NMDAR interaction with CRMP2. Unrestricted Ca2+ influx through NMDARs leading to delayed calcium dysregulation and neuronal cell death was blocked by all peptides but MAP-CBD3. When applied acutely for 10 minutes, R9-CBD3 was more effective than TAT-CBD3 at neuroprotection while MTS- and MAP-CBD3 were ineffective. In contrast, long-term (> 24 hours treatment with MTS-CBD3 conferred neuroprotection where TAT-CBD3 failed. Neither peptide altered surface trafficking of NMDARs. Neuroprotection conferred by MTS-CBD3 peptide is likely due to its increased uptake coupled with decreased efflux when compared to TAT-CBD3. Overall, our results demonstrate that altering CPPs can bestow differential neuroprotective potential onto the CBD3 cargo.

  5. Evaluation of anti-HER2 scFv-conjugated PLGA-PEG nanoparticles on 3D tumor spheroids of BT474 and HCT116 cancer cells

    Science.gov (United States)

    Thuy Duong Le, Thi; Pham, Thu Hong; Nghia Nguyen, Trong; Giang Ngo, Thi Hong; Nhung Hoang, Thi My; Huan Le, Quang

    2016-06-01

    Three-dimensional culture cells (spheroids) are one of the multicellular culture models that can be applied to anticancer chemotherapeutic development. Multicellular spheroids more closely mimic in vivo tumor-like patterns of physiologic environment and morphology. In previous research, we designed docetaxel-loaded pegylated poly(D, L-lactide-co-glycolide) nanoparticles conjugated with anti-HER2 single chain antibodies (scFv-Doc-PLGA-PEG) and evaluated them in 2D cell culture. In this study, we continuously evaluate the cellular uptake and cytotoxic effect of scFv-Doc-PLGA-PEG on a 3D tumor spheroid model of BT474 (HER2-overexpressing) and HCT116 (HER2-underexpressing) cancer cells. The results showed that the nanoparticle formulation conjugated with scFv had a significant internalization effect on the spheroids of HER2-overexpressing cancer cells as compared to the spheroids of HER2-underexpressing cancer cells. Therefore, cytotoxic effects of targeted nanoparticles decreased the size and increased necrotic score of HER2-overexpressing tumor spheroids. Thus, these scFv-Doc-PLGA-PEG nanoparticles have potential for active targeting for HER2-overexpressing cancer therapy. In addition, BT474 and HCT116 spheroids can be used as a tumor model for evaluation of targeting therapies.

  6. Persistence Mechanisms of Conjugative Plasmids

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Hansen, Lars H.; Sørensen, Søren Johannes

    2009-01-01

    Are plasmids selfish parasitic DNA molecules or an integrated part of the bacterial genome? This chapter reviews the current understanding of the persistence mechanisms of conjugative plasmids harbored by bacterial cells and populations. The diversity and intricacy of mechanisms affecting...... the successful propagation and long-term continued existence of these extra-chromosomal elements is extensive. Apart from the accessory genetic elements that may provide plasmid-harboring cells a selective advantage, special focus is placed on the mechanisms conjugative plasmids employ to ensure their stable...... maintenance in the host cell. These importantly include the ability to self-mobilize in a process termed conjugative transfer, which may occur across species barriers. Other plasmid stabilizing mechanisms include the multimer resolution system, active partitioning, and post-segregational-killing of plasmid...

  7. To determine the cytotoxicity of chlorambucil and one of its nitro-derivatives, conjugated to prasterone and pregnenolone, towards eight human cancer cell-lines.

    Science.gov (United States)

    Shervington, Leroy A; Smith, Nigel; Norman, Emma; Ward, Timothy; Phillips, Roger; Shervington, Amal

    2009-07-01

    Four ester prodrugs derived from the bifunctional alkylating agent chlorambucil, and one of its nitro-derivatives, 3-nitrochlorambucil conjugated to prasterone and pregnenolone, were synthesized and tested for their cytotoxic activity against eight human cell lines, using the standard MTT assay. A comparison between the esters and the controls, namely chlorambucil and 3-nitrochlorambucil would suggest that all four esters possess to varying degrees, specificity towards the breast adenocarcinoma cell line (MDA-mb468) than the other seven cells' lines tested. The overall findings are encouraging since it infers that these lipophilic esters not only have the ability to traverse specific cell membranes but also exhibit cytotoxicity towards most of the cell lines tested.

  8. Nasal immunization with M cell-targeting ligand-conjugated ApxIIA toxin fragment induces protective immunity against Actinobacillus pleuropneumoniae infection in a murine model.

    Science.gov (United States)

    Park, Jisang; Seo, Ki-Weon; Kim, Sae-Hae; Lee, Ha-Yan; Kim, Bumseok; Lim, Chae Woong; Kim, Jin-Hee; Yoo, Han Sang; Jang, Yong-Suk

    2015-05-15

    Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia and severe economic loss in the swine industry has been caused by the infection. Therefore, the development of an effective vaccine against the bacteria is necessary. ApxII toxin, among several virulence factors expressed by the bacteria, is considered to be a promising vaccine candidate because ApxII toxin not only accompanies cytotoxic and hemolytic activities, but is also expressed in all 15 serotypes of bacteria except serotypes 10 and 14. In this study, we identified the peptide ligand capable of targeting the ligand-conjugated ApxIIA #5 fragment antigen to nasopharynx-associated lymphoid tissue. It was found that nasal immunization with ligand-conjugated ApxIIA #5 induced efficient mucosal and systemic immune responses measured at the levels of antigen-specific antibodies, cytokine-secreting cells after antigen exposure, and antigen-specific lymphocyte proliferation. More importantly, the nasal immunization induced protective immunity against nasal challenge infection of the bacteria, which was confirmed by histopathological studies and bacterial clearance after challenge infection. Collectively, we confirmed that the ligand capable of targeting the ligand-conjugated antigen to nasopharynx-associated lymphoid tissue can be used as an effective nasal vaccine adjuvant to induce protective immunity against A. pleuropneumoniae infection. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. 10-valent pneumococcal non-typeable Haemophilus influenzae protein-D conjugate vaccine (PHiD-CV) induces memory B cell responses in healthy Kenyan toddlers.

    Science.gov (United States)

    Muema, D M; Nduati, E W; Uyoga, M; Bashraheil, M; Scott, J A G; Hammitt, L L; Urban, B C

    2015-08-01

    Memory B cells are long-lived and could contribute to persistence of humoral immunity by maintaining the plasma-cell pool or making recall responses upon re-exposure to an antigen. We determined the ability of a pneumococcal conjugate vaccine to induce anti-pneumococcal memory B cells. Frequencies of memory B cells against pneumococcal capsular polysaccharides from serotypes 1, 6B, 14, 19F and 23F were determined by cultured B cell enzyme-linked immunospot (ELISPOT) in 35 children aged 12-23 months who received pneumococcal non-typeable Haemophilus influenzae protein-D conjugate vaccine (PHiD-CV). The relationships between plasma antibodies and memory B cell frequencies were also assessed. After two doses of PHiD-CV, the proportion of subjects with detectable memory B cells against pneumococcal capsular polysaccharides increased significantly for serotypes 1 (3-45%; P < 0·01), 19F (21-66%; P < 0·01) and 23F (13-36%; P = 0·02), but not serotypes 6B (24-42%; P = 0·24) and 14 (21-40%; P = 0·06). Correlations between antibodies and memory B cells were weak. Carriage of serotype 19F at enrolment was associated with poor memory B cell responses against this serotype at subsequent time-points (day 30: non-carriers, 82% versus carriers, 0%, P < 0·01; day 210: non-carriers, 72% versus carriers, 33%, P = 0·07). PHiD-CV is capable of inducing memory B cells against some of the component pneumococcal capsular polysaccharides.

  10. Cytotoxicity of folic acid conjugated hollow silica nanoparticles toward Caco2 and 3T3 cells, with and without encapsulated DOX.

    Science.gov (United States)

    Patel, Kunal; Sundara Raj, Behin; Chen, Yan; Lou, Xia

    2016-04-01

    Hollow silica nanoparticles of two sizes with and without a folic acid targeting ligand were synthesized. Fickian diffusion of the antitumor drug doxorubicin hydrochloride (DOX) was demonstrated by the produced nanoparticles, achieving a cumulative release of 73% and 45% for 215 nm and 430 nm particles respectively over a period of 500 h. The hollow silica nanoparticles presented a time and dose dependent toxicity, selective to human epithelial colorectal adenocarcinoma (Caco2) cells, over mouse embryonic fibroblast (3T3) cells. At 24h Caco2 cell viability was reduced to 66% using pure hollow silica at a concentration of 50 μg mL(-1), while that of 3T3 cells remained at 94% under the same conditions. The selective cytotoxicity of hollow silica nanoparticles was further enhanced by conjugation of folic acid and incorporation of DOX: at 24h and an equivalent DOX concentration of 0.5 μg mL(-1), viable Caco2 cells were reduced to 45% while 3T3 cells were reduced to 83%. Interestingly the equivalent dose of free DOX was more toxic to 3T3 than to Caco2 cells, reducing the 3T3 viability to 72% and the Caco2 viability to 80%, which is likely due to the presence of the p-glycoprotein pumps in Caco2 cells. Folic acid conjugation served to enhance the viability of both cell lines in this work. Careful optimization of the folate content should further improve the cell specificity of the hollow silica nanoparticles, thus providing a viable targeting platform for cancer therapy.

  11. Synthesis and Characterization of Anti-HER2 Antibody Conjugated CdSe/CdZnS Quantum Dots for Fluorescence Imaging of Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Takashi Jin

    2009-11-01

    Full Text Available The early detection of HER2 (human epidermal growth factor receptor 2 status in breast cancer patients is very important for the effective implementation of anti-HER2 antibody therapy. Recently, HER2 detections using antibody conjugated quantum dots (QDs have attracted much attention. QDs are a new class of fluorescent materials that have superior properties such as high brightness, high resistance to photo-bleaching, and multi-colored emission by a single-light source excitation. In this study, we synthesized three types of anti-HER2 antibody conjugated QDs (HER2Ab-QDs using different coupling agents (EDC/sulfo-NHS, iminothiolane/sulfo-SMCC, and sulfo-SMCC. As water-soluble QDs for the conjugation of antibody, we used glutathione coated CdSe/CdZnS QDs (GSH-QDs with fluorescence quantum yields of 0.23~0.39 in aqueous solution. Dispersibility, hydrodynamic size, and apparent molecular weights of the GSH-QDs and HER2Ab-QDs were characterized by using dynamic light scattering, fluorescence correlation spectroscopy, atomic force microscope, and size-exclusion HPLC. Fluorescence imaging of HER2 overexpressing cells (KPL-4 human breast cancer cell line was performed by using HER2Ab-QDs as fluorescent probes. We found that the HER2Ab-QD prepared by using SMCC coupling with partially reduced antibody is a most effective probe for the detection of HER2 expression in KPL-4 cells. We have also studied the size dependency of HER2Ab-QDs (with green, orange, and red emission on the fluorescence image of KPL-4 cells.

  12. Growth inhibition of human melanoma tumor cells by the combination of sodium phenylacetate (NaPA) and substituted dextrans and one NaPA-dextran conjugate.

    Science.gov (United States)

    Gervelas, C; Avramoglou, T; Crépin, M; Jozefonvicz, J

    2002-01-01

    We have studied the cytostatic effects of sodium phenylacetate (NaPA) in association with several substituted dextrans on human tumor melanoma 1205LU cells. We show that NaPA alone inhibits the growth of these cells (IC50 = 3.9 mM) while a weak inhibitory effect appears at a concentration of 37 microM (10 microg/ml) for a dextran methyl carboxylate benzylamide (LS17-DMCB). The precursors of LS17-DMCB [T40 Dextran and carboxymethyl dextran (LS17-DMC)] did not affect the growth of 1205LU cells. To potentiate the inhibitory activity of NaPA at low concentrations (below 5.6 mM), we have tested NaPA and LS17-DMCB in physical mixture (association) or linked together covalently (this conjugate is termed 'LS17-NaPaC'). We have observed an increase of the 1205LU cell growth inhibition effect with NaPA in association (IC50 1.8 mM). For a concentration of 5 mM of NaPA (free in the case of association or linked in the case of conjugate), the association with dextran derivative exhibits a 4.6-fold higher efficacy than with NaPA alone (9 versus 41% surviving fraction), while the conjugate is 1.3-fold smaller (52% growth inhibition). By performing isobologram analysis of the IC50 data, we have shown a synergistic effect for a particular molar ratio of NaPA and LS17-DMCB (NaPA:LS17-DMCB = 0.35).

  13. Conjugation of cell-penetrating peptides with poly(lactic-co-glycolic acid)-polyethylene glycol nanoparticles improves ocular drug delivery

    Science.gov (United States)

    Vasconcelos, Aimee; Vega, Estefania; Pérez, Yolanda; Gómara, María J; García, María Luisa; Haro, Isabel

    2015-01-01

    In this work, a peptide for ocular delivery (POD) and human immunodeficiency virus transactivator were conjugated with biodegradable poly(lactic-co-glycolic acid) (PGLA)–polyethylene glycol (PEG)-nanoparticles (NPs) in an attempt to improve ocular drug bioavailability. The NPs were prepared by the solvent displacement method following two different pathways. One involved preparation of PLGA NPs followed by PEG and peptide conjugation (PLGA-NPs-PEG-peptide); the other involved self-assembly of PLGA-PEG and the PLGA-PEG-peptide copolymer followed by NP formulation. The conjugation of the PEG and the peptide was confirmed by a colorimetric test and proton nuclear magnetic resonance spectroscopy. Flurbiprofen was used as an example of an anti-inflammatory drug. The physicochemical properties of the resulting NPs (morphology, in vitro release, cell viability, and ocular tolerance) were studied. In vivo anti-inflammatory efficacy was assessed in rabbit eyes after topical instillation of sodium arachidonate. Of the formulations developed, the PLGA-PEG-POD NPs were the smaller particles and exhibited greater entrapment efficiency and more sustained release. The positive charge on the surface of these NPs, due to the conjugation with the positively charged peptide, facilitated penetration into the corneal epithelium, resulting in more effective prevention of ocular inflammation. The in vitro toxicity of the NPs developed was very low; no ocular irritation in vitro (hen’s egg test–chorioallantoic membrane assay) or in vivo (Draize test) was detected. Taken together, these data demonstrate that PLGA-PEG-POD NPs are promising vehicles for ocular drug delivery. PMID:25670897

  14. Targeting urokinase and the transferrin receptor with novel, anti-mitotic N-alkylisatin cytotoxin conjugates causes selective cancer cell death and reduces tumor growth.

    Science.gov (United States)

    Vine, K L; Indira Chandran, V; Locke, J M; Matesic, L; Lee, J; Skropeta, D; Bremner, J B; Ranson, M

    2012-01-01

    Tumor-specific delivery of ligand-directed prodrugs can increase the therapeutic window of chemotherapeutics by maintaining efficacy whilst decreasing toxic side effects. We have previously described a series of synthetic N-alkylated isatin cytotoxins that destabilize microtubules and induce apoptosis with 10-fold greater potency than conventional anti-mitotics in vitro. Here, we report the characterization, in vitro cytotoxicity and in vivo efficacy of a lead compound, 5,7-dibromo-N-(p-hydroxymethylbenzyl)isatin (N-AI) conjugated via an esterase-labile linker (N-AIE) to two proven targeting ligands, transferrin (Tf) and plasminogen activator inhibitor type 2 (PAI-2/serpinB2). N-AI was released from N-AIE and the targeting ligands Tf/PAI-2 in an esterase-dependent manner at 37 C and both Tf- and PAI-2-N-AIE conjugates were stable at physiological pH. Human cancer cell lines which vary in their expression levels of Tf receptor (TfR/CD71) and PAI-2 target, receptor bound urokinase (uPA) selectively internalized the conjugates. Tf-N-AIE was up to 24 times more active than the free drug and showed clear selectivity patterns based on TfR levels. PAI-2-N-AIE showed equivalent activity compared to the parent drug and strong selectivity patterns for uPA levels. In preliminary in vivo experiments, the PAI-2- and Tf-N-AIE conjugates were efficacious at 1/20(th) and 1/10(th) of the dose of the free N-AI, respectively, in a metastatic, orthotopic human breast tumor xenograft mouse model. Thus, this strategy specifically delivers and concentrates a novel class of isatin-based, tubulin destabilizing agents to tumors in vivo and warrants further detailed preclinical investigation.

  15. n-Type Water/Alcohol-Soluble Naphthalene Diimide-Based Conjugated Polymers for High-Performance Polymer Solar Cells.

    Science.gov (United States)

    Wu, Zhihong; Sun, Chen; Dong, Sheng; Jiang, Xiao-Fang; Wu, Siping; Wu, Hongbin; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2016-02-17

    With the demonstration of small-area, single-junction polymer solar cells (PSCs) with power conversion efficiencies (PCEs) over the 10% performance milestone, the manufacturing of high-performance large-area PSC modules is becoming the most critical issue for commercial applications. However, materials and processes that are optimized for fabricating small-area devices may not be applicable for the production of high-performance large-area PSC modules. One of the challenges is to develop new conductive interfacial materials that can be easily processed with a wide range of thicknesses without significantly affecting the performance of the PSCs. Toward this goal, we report two novel naphthalene diimide-based, self-doped, n-type water/alcohol-soluble conjugated polymers (WSCPs) that can be processed with a broad thickness range of 5 to 100 nm as efficient electron transporting layers (ETLs) for high-performance PSCs. Space charge limited current and electron spin resonance spectroscopy studies confirm that the presence of amine or ammonium bromide groups on the side chains of the WSCP can n-dope PC71BM at the bulk heterojunction (BHJ)/ETL interface, which improves the electron extraction properties at the cathode. In addition, both amino functional groups can induce self-doping to the WSCPs, although by different doping mechanisms, which leads to highly conductive ETLs with reduced ohmic loss for electron transport and extraction. Ultimately, PSCs based on the self-doped WSCP ETLs exhibit significantly improved device performance, yielding PCEs as high as 9.7% and 10.11% for PTB7-Th/PC71BM and PffBT4T-2OD/PC71BM systems, respectively. More importantly, with PffBT4T-2OD/PC71BM BHJ as an active layer, a prominent PCE of over 8% was achieved even when a thick ETL of 100 nm was used. To the best of our knowledge, this is the highest efficiency demonstrated for PSCs with a thick interlayer and light-harvesting layer, which are important criteria for eventually making

  16. A stilbene that binds selectively to transthyretin in cells and remains dark until it undergoes a chemoselective reaction to create a bright blue fluorescent conjugate.

    Science.gov (United States)

    Choi, Sungwook; Ong, Derrick Sek Tong; Kelly, Jeffery W

    2010-11-17

    We describe a non-fluorescent, second generation stilbene that very selectively binds to transthyretin in complex biological environments and remains dark until it chemoselectively reacts with the pK(a)-perturbed Lys-15 ε-amino group of transthyretin to form a bright blue fluorescent conjugate. Stilbene A2 is mechanistically unusual in that it remains non-fluorescent in cell lysates lacking transthyretin, even though there is likely some proteome binding. Thus, it is especially useful for cellular imaging, as background fluorescence is undetectable until A2 reacts with transthyretin. The mechanistic basis for the effective lack of environment-sensitive fluorescence of A2 when bound to, but before reacting with, transthyretin is reported. Stilbene A2 exhibits sufficiently rapid transthyretin conjugation kinetics at 37 °C to enable pulse-chase experiments to be performed, in this case demonstrating that transthyretin is secreted from HeLa cells. As the chase compound, we employed C1, a cell-permeable, highly selective, non-covalent, transthyretin-binding dihydrostilbene that cannot become fluorescent. The progress reported is viewed as a first and necessary step toward our long-term goal of creating a one-chain, one-binding-site transthyretin tag, whose fluorescence can be regulated by adding A2 or an analogous molecule. Fusing proteins of interest to a one-chain, one-binding-site transthyretin tag regulated by A2 should be useful for studying folding, trafficking, and degradation in the cellular secretory pathway, utilizing pulse-chase experiments. Immediate applications of A2 include utilizing its conjugate fluorescence to quantify transthyretin concentration in human plasma, reflecting nutritional status, and determining the binding stoichiometry of kinetic stabilizer drugs to transthyretin in plasma.

  17. Cyclopentenone prostaglandin, 15-deoxy-Delta12,14-PGJ2, is metabolized by HepG2 cells via conjugation with glutathione.

    Science.gov (United States)

    Brunoldi, Enrico M; Zanoni, Giuseppe; Vidari, Giovanni; Sasi, Soumya; Freeman, Michael L; Milne, Ginger L; Morrow, Jason D

    2007-10-01

    15-deoxy-Delta12,14-prostaglandin J2 (15-d-PGJ2) is a dehydration product of PGD2. This compound possesses a highly reactive polyunsaturated carbonyl moiety that is a substrate for Michael addition with thiol-containing biomolecules such as glutathione and cysteine residues on proteins. By reacting with glutathione and proteins, 15-d-PGJ2 is believed to exert potent biological activity. Despite the large number of publications that have ascribed bioactivity to this molecule, it is not known to what extent 15-d-PGJ2 is formed in vivo. Levels of free 15-d-PGJ2 measured in human biological fluids such as urine are low, and the biological importance of this compound has thus been questioned. Because of its reactivity, we hypothesized that 15-d-PGJ2 is present in vivo primarily as a Michael conjugate. Therefore, we undertook a detailed study of the metabolism of this compound in HepG2 cells that are known to metabolize other cyclopentenone eicosanoids. We report that HepG2 cells primarily convert 15-d-PGJ2 to a glutathione conjugate in which the carbonyl at C-11 is reduced to a hydroxyl. Subsequently, the glutathione portion of the molecule is hydrolyzed with loss of glutamic acid and glycine resulting in a cysteine conjugate. These findings confirm a general route for the metabolism of cyclopentenone eicosanoids in HepG2 cells and may pave the way for new insights regarding the formation of 15-d-PGJ2 in vivo.

  18. Conjugates of folic acids with BSA-coated quantum dots for cancer cell targeting and imaging by single-photon and two-photon excitation.

    Science.gov (United States)

    Meng, He; Chen, Ji-Yao; Mi, Lan; Wang, Pei-Nan; Ge, Mei-Ying; Yue, Yang; Dai, Ning

    2011-01-01

    Bovine serum albumin (BSA)-coated CdTe/ZnS quantum dots (BSA-QDs) were selected to conjugate with folic acid (FA), forming FA-BSA-QDs. This study aims to develop these small FA-BSA-QDs (less than 10 nm) for the diagnosis of cancers in which the FA receptor (FR) is overexpressed. The enhancement of cellular uptake in FR-positive human nasopharyngeal carcinoma cells (KB cells) for FA-BSA-QDs was found by means of confocal fluorescence microscopy under single-photon and two-photon excitation. The uptake enhancement for FA-BSA-QDs was further evaluated by flow-cytometric analysis in 10(4) KB cells, and was about 3 times higher than for BSA-QDs on average. The uptake enhancement was suppressed when KB cells had been pretreated with excess FA, reflecting that the enhancement was mediated by the association of FR at cell membranes with FA-BSA-QDs. When human embryonic kidney cells (293T) (FR-negative cells) and KB cells, respectively, were incubated with FA-BSA-QDs (1 μM) for 40 min, the FA-BSA-QD uptake by 293T cells was much weaker than that by KB cells, demonstrating that FA-BSA-QDs could undergo preferential binding on FR-positive cancer cells. These characteristics suggest that FA-BSA-QDs are potential candidates for cancer diagnosis.

  19. Characterization of the paclitaxel loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer targeting HER-2 overexpressing breast cancer cells

    Science.gov (United States)

    Thach Nguyen, Kim; Nguyen, Thu Ha; Do, Dinh Ho; Huan Le, Quang

    2017-03-01

    In this work we report the isolation of DNA aptamer that is specifically bound to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. Paclitaxel (PTX) loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer was synthesized and its structure was confirmed by TEM image. This binary mixed system consisting of DNA aptamer modified Pluronic F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Morphology images confirmed the existence of PTX micelles, with an average size of approximately 86.22 ± 1.45 nm diameters. Drug release profile showed that the PTX conjugate maintained a sustained PTX release. From in vitro cell experiment it was shown that 89%–93%, 50%–58%, 55%–62%, 24%–28% and 2%–7% of the SK-BR-3, NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31, respectively, were dead after 6–48 h. These results demonstrated a novel DNA aptamer-micelle assembly for efficient detection and a system for the delivery of PTX targeting specific HER-2 overexpressing. We have also successfully cultivated cancer tissues of explants from Vietnamese patients on a type I collagen substrate. The NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31cell lines were used as cellular model sources for the study of chemotherapy drug in cancer.

  20. Self-assembled all-conjugated block copolymer as an effective hole conductor for solid-state dye-sensitized solar cells.

    Science.gov (United States)

    Chen, Wei-Chih; Lee, Yi-Huan; Chen, Chia-Yuan; Kau, Kuo-Chang; Lin, Lu-Yin; Dai, Chi-An; Wu, Chun-Guey; Ho, Kuo-Chuan; Wang, Juen-Kai; Wang, Leeyih

    2014-02-25

    An all-conjugated diblock copolymer, poly(2,5-dihexyloxy-p-phenylene)-b-poly(3-hexylthiophene) (PPP-b-P3HT), was synthesized and applied as a hole transport material (HTM) for the fabrication of solid-state dye-sensitized solar cells (ss-DSCs). This copolymer is characterized by an enhanced crystallinity, enabling its P3HT component to self-organize into interpenetrated and long-range-ordered crystalline fibrils upon spin-drying and ultimately endowing itself to have a faster hole mobility than that of the parent P3HT homopolymer. Transient photovoltage measurements indicate that the photovoltaic cell based on PPP-b-P3HT as the HTM has a longer electron lifetime than that of the reference device based on P3HT homopolymer. Moreover, comparing the two ss-DSCs in terms of the electrochemical impedance spectra reveals that the electron density in the TiO2 conduction band is substantially higher in the PPP-b-P3HT device than in the P3HT cell. Above observations suggest that the PPP block facilitates an intimate contact between the copolymer and dye molecules absorbed on the nanoporous TiO2 layer, which significantly enhances the performance of the resulting device. Consequently, the PPP-b-P3HT ss-DSC exhibits a promising power conversion efficiency of 4.65%. This study demonstrates that conjugated block copolymers can function as superior HTMs of highly efficient ss-DSCs.

  1. Conjugated agent insulin-antisense-c-myb-PS-ODN enhances the inhibitory effect on proliferation of rat aortic artery smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM:Vascular smooth muscle cell (SMC) proliferation and migration from the arterial wall media into the intima are believed to play a critical role in the pathogenesis of restenosis. Several studies have demonstrated that phosphothioate (PS) oligodeoxynucleotides targeted against genes involved in SMC proliferation inhibits in vitro SMC proliferation and migration. However, the therapeutic effect of antisense ODN on the individual who receives the treatment of delivery of the agent depends on the efficacy of this agent in great degree. We investigated the inhibition effect of a novel agent, insulin-antisense-c-myb-PS-ODN on SMC proliferation in vitro. METHODS:The rat aortic artery SMCs were cultured in Dulbecco's modified Eagel's medium. The passage 8 to 13 were used as the experiment. Cell surface receptor binding assay was quantified through counting gamma particles emitted from 125    I labeled insulin. SMC rapid proliferation was brought by stimulation of high concentration of fetal bovine serum (FBS). The novel agent of insulin conjugated to the antisense-c-myb-PS-ODN was obtained via incubation of both in condition of certain reagents, pH, temperature, and ion concentration. The characterization and purification of the agent was performed through HPLC. Inhibition of SMC proliferation was reflected by incorporation rate of trillium labeled thymidine deoxyribonucleotide.RESULTS:The binding efficacy of insulin to the receptor was remarkably increased in SMC cultured in supplement of 20% FBS. The inhibition effect of conjugator insulin-c-myb-antisense-PS-ODN was stronger than that of the simple c-myb-antisense-PS-ODN. The inhibition rate of conjugator and simple form on SMC proliferation were 48.34% and 29.54%, respectively. CONCLUSION:The binding efficacy and specificity of c-myb-antisense-PS-ODN to SMC may be enhanced by the insulin receptor mediation through the insulin-insulin receptor interaction. The insulin-receptor targeted method may be a

  2. Conjugate spacer effect on molecular structures and absorption spectra of triphenylamine dyes for sensitized solar cells: density functional theory calculations.

    Science.gov (United States)

    Xu, Jie; Wang, Lei; Liang, Guijie; Bai, Zikui; Wang, Luoxin; Xu, Weilin; Shen, Xiaolin

    2011-01-01

    The molecular structures and absorption spectra of triphenylamine dyes containing variable thiophene units as the spacers (TPA1-TPA3) were investigated by density functional theory (DFT) and time-dependent DFT. The calculated results indicate that the strong conjugation is formed in the dyes and the length of conjugate bridge increases gradually with the increased thiophene spacers. The interfacial charge transfer between the TiO2 electrode and TPA1-TPA3 are electron injection processes from the excited dyes to the semiconductor conduction band. The simulated absorption bands are assigned to π→π* transitions, which exhibit appreciable red-shift with respect to the experimental bands due to the lack of direct solute-solvent interaction and the inherent approximations in TD-DFT. The effect of thiophene spacers on the molecular structures, absorption spectra and photovoltaic performance were comparatively discussed and points out that the choice of appropriate conjugate bridge is very important for the design of new dyes with improved performance.

  3. Photodynamic effects induced by meso-tris(pentafluorophenyl)corrole and its cyclodextrin conjugates on cytoskeletal components of HeLa cells.

    Science.gov (United States)

    Barata, Joana F B; Zamarrón, Alicia; Neves, M Graça P M S; Faustino, M Amparo F; Tomé, Augusto C; Cavaleiro, José A S; Röder, Beate; Juarranz, Ángeles; Sanz-Rodríguez, Francisco

    2015-03-06

    The aim of this work was to synthesize new corrole β-cyclodextrin conjugates βCD1 (with one β-cyclodextrin moiety) and βCD2 (with two β-cyclodextrin moieties) from 5,10,15-tris(pentafluorophenyl)corrole (TPFC) and to test in vitro the efficacy of these compounds towards tumoral HeLa cells. No dark cytotoxicity was observed for TPFC and βCD1 at the concentration used for PDT cell treatment, even during long incubation periods (24 h). Fluorescence microscopy showed that TPFC and βCD1 accumulate in HeLa cells at lysosomes and in the Golgi apparatus, respectively. The cell survival after the PDT treatment with visible light was dependent on light exposure level and compound concentration. βCD1 was able to penetrate efficiently in the cytoplasm of the HeLa cells. In particular, we have analyzed the photodynamic effect of the corrole derivatives on the microtubules of HeLa cells and the morphological alterations on the mitotic spindle. TPFC and βCD1 caused photocytotoxicity in tumoral HeLa cells and induced a rapid metaphase blockage of cells that also showed clearly altered configurations of the mitotic spindle. The results showed that TPFC has the highest photosensitizing efficiency on tumoral cells.

  4. Oral Gavage Delivery of PR8 Antigen with β-Glucan-Conjugated GRGDS Carrier to Enhance M-Cell Targeting Ability and Induce Immunity.

    Science.gov (United States)

    Lee, Dong-Yi; Nurunnabi, Md; Kang, Sung Hun; Nafiujjaman, Md; Huh, Kang Moo; Lee, Yong-Kyu; Kim, Yeu-Chun

    2017-04-10

    Oral gavage is known as one of most convenient routes for therapeutic administration in comparison with other available routes such as intravenous, intra muscular, suppository, etc. An oral vaccine delivery system has additional potential as it may provide a convenient way to prevent infectious diseases by introducing optimum immunization in mucus. Although oral vaccine delivery has attracted tremendous interest in vaccine delivery research, various limitations have prevented its rate of progress up to the level that was initially expected. However, the major problems of oral vaccine delivery are vaccine instability and lack of absorbability, resulting from degradation of the sophisticated antigens in the acidic medium in the stomach. In order to obtain adequate microfold-cell (M-cell) targeting and uptake, the therapeutic material is required to pass through the stomach and reach the small intestine without degradation. In this project, we have introduced a conjugate of β-glucan and Glycine-Arginine-Glycine-Aspartic acid-Serine (GRGDS) that is effective for simultaneous protection of the antigen (PR8) and M-cell targeting. According to the experimental results, the cationic β-glucan-GRGDS conjugate can encapsulate a certain amount of anionic PR8 through electrostatic interaction, which forms nanoparticles with a range of diameter of 200-250 nm. Also, the PR8 incorporated nanoparticles showed high cell viability and stability in diverse environments. Finally, excellent M-cell targeting ability was verified in an in vitro M-cell model. Most importantly, the in vivo test obviously demonstrated the superiority of this system, which significantly increases antibody concentration in serum, intestine, and mucus as measured 21 days after immunization.

  5. Hydrophilic Conjugated Polymers with Large Bandgaps and Deep-Lying HOMO Levels as an Efficient Cathode Interlayer in Inverted Polymer Solar Cells.

    Science.gov (United States)

    Kan, Yuanyuan; Zhu, Yongxiang; Liu, Zhulin; Zhang, Lianjie; Chen, Junwu; Cao, Yong

    2015-08-01

    Two hydrophilic conjugated polymers, PmP-NOH and PmP36F-NOH, with polar diethanol-amine on the side chains and main chain structures of poly(meta-phenylene) and poly(meta-phenylene-alt-3,6-fluorene), respectively, are successfully synthesized. The films of PmP-NOH and PmP36F-NOH show absorption edges at 340 and 343 nm, respectively. The calculated optical bandgaps of the two polymers are 3.65 and 3.62 eV, respectively, the largest ones so far reported for hydrophilic conjugated polymers. PmP-NOH and PmP36F-NOH also possess deep-lying highest occupied molecular orbital levels of -6.19 and -6.15 eV, respectively. Inserting PmP-NOH and PmP36F-NOH as a cathode interlayer in inverted polymer solar cells with a PTB7/PC71 BM blend as the active layer, high power conversion efficiencies of 8.58% and 8.33%, respectively, are achieved, demonstrating that the two hydrophilic polymers are excellent interlayers for efficient inverted polymer solar cells.

  6. Computational study on the effects of substituent and heteroatom on physical properties and solar cell performance in donor-acceptor conjugated polymers based on benzodithiophene.

    Science.gov (United States)

    Zhang, Lvyong; Shen, Wei; He, Rongxing; Liu, Xiaorui; Fu, Zhiyong; Li, Ming

    2014-11-01

    Computationally driven material design has attracted increasing interest to accelerate the search for optimal conjugated donor materials in bulk heterojunction organic solar cells. A series of novel copolymers containing benzo[1,2-b:4,5-b']dithiophene (BDT) and thieno[3,4-c]pyrrole-4,6-dione (TPD) derivatives were simulated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). We performed a systematic study on the influences on molecular geometry parameters, electronic properties, optical properties, photovoltaic performances, and intermolecular stacking as well as hole mobility when different chalcogenophenes in TPD derivatives were used and functional groups with different electron-withdrawing abilities such as alkyl, fluorine, sufonyl, and cyano were introduced to the nitrogen positions in electron-deficient units. The substitution position of electron-withdrawing groups may cause little steric hindrance to the neighboring donor units, especially fluorine and cyano group. It was found that the incorporation of these new electron-deficient substituents and sulfur-selenium exchange can be applicable to further modify and optimize existing molecular structures. Our findings will provide valuable guidance and chemical methodologies for a judicious material design of conjugated polymers for solar cell applications with desirable photovoltaic characteristics.

  7. Anti-PDGF receptor β antibody-conjugated squarticles loaded with minoxidil for alopecia treatment by targeting hair follicles and dermal papilla cells.

    Science.gov (United States)

    Aljuffali, Ibrahim A; Pan, Tai-Long; Sung, Calvin T; Chang, Shu-Hao; Fang, Jia-You

    2015-08-01

    This study developed lipid nanocarriers, called squarticles, conjugated with anti-platelet-derived growth factor (PDGF)-receptor β antibody to determine whether targeted Minoxidil (MXD) delivery to the follicles and dermal papilla cells (DPCs) could be achieved. Squalene and hexadecyl palmitate (HP) were used as the matrix of the squarticles. The PDGF-squarticles showed a mean diameter and zeta potential of 195 nm and -46 mV, respectively. Nanoparticle encapsulation enhanced MXD porcine skin deposition from 0.11 to 0.23 μg/mg. The antibody-conjugated nanoparticles ameliorated follicular uptake of MXD by 3-fold compared to that of the control solution in the in vivo mouse model. Both vertical and horizontal skin sections exhibited a wide distribution of nanoparticles in the follicles, epidermis, and deeper skin strata. The encapsulated MXD moderately elicited proliferation of DPCs and vascular endothelial growth factor (VEGF) expression. The active targeting of PDGF-squarticles may be advantageous to improving the limited success of alopecia therapy. Topical use of minoxidil is only one of the very few treatment options for alopecia. Nonetheless, the current delivery method is far from ideal. In this article, the authors developed lipid nanocarriers with anti-platelet-derived growth factor receptor ? antibody to target dermal papilla cells, and showed enhanced uptake of minoxidil. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Astatine-211 conjugated to an anti-CD20 monoclonal antibody eradicates disseminated B-cell lymphoma in a mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Green, Damian J.; Shadman, Mazyar; Jones, Jon C.; Frayo, Shani; Kenoyer, Aimee L.; Hylarides, Mark; Hamlin, Donald K.; Wilbur, D. Scott; Balkan, Ethan R.; Lin, Yukang; Miller, Brian W.; Frost, Sophia; Gopal, Ajay K.; Orozco, Johnnie J.; Gooley, Ted; Laird, Kelley L.; Till, B. G.; Back, Tom; Sandmaier, B. M.; Pagel, John M.; Press, Oliver W.

    2015-03-26

    Alpha emitting radionuclides release a large amount of energy within a few cell diameters and may be particularly effective for radioimmunotherapy targeting minimal residual disease (MRD) conditions in which micrometastatic disease satellites are broadly distributed. To evaluate this hypothesis, 211At conjugated 1F5 mAb (anti-CD20) was studied in both bulky lymphoma tumor xenograft and MRD animal models. Superior treatment responses to 211At conjugated 1F5 mAb were evident in the MRD setting. Lymphoma xenograft tumor bearing animals treated with doses of up to 48µCi of anti-CD20 211At-decaborate [211At-B10-1F5] experienced modest responses (0% cures but 2-3-fold prolongation of survival compared to negative controls). In contrast, 70% of animals in the MRD lymphoma model demonstrated complete eradication of disease when treated with 211At-B10-1F5 at a radiation dose that was less than one-third (15 µCi) of the highest dose given to xenograft animals. Tumor progression among untreated control animals in both models was uniformly lethal. After 130 days, no significant renal or hepatic toxicity is observed in the cured animals receiving 15 µCi of 211At-B10-1F5. These findings suggest that in a MRD lymphoma model, where isolated cells and tumor microclusters prevail, α-emitters may be uniquely efficacious.

  9. Long-term tumor regression induced by an antibody-drug conjugate that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells.

    Science.gov (United States)

    Sapra, Puja; Damelin, Marc; Dijoseph, John; Marquette, Kimberly; Geles, Kenneth G; Golas, Jonathon; Dougher, Maureen; Narayanan, Bitha; Giannakou, Andreas; Khandke, Kiran; Dushin, Russell; Ernstoff, Elana; Lucas, Judy; Leal, Mauricio; Hu, George; O'Donnell, Christopher J; Tchistiakova, Lioudmila; Abraham, Robert T; Gerber, Hans-Peter

    2013-01-01

    Antibody-drug conjugates (ADC) represent a promising therapeutic modality for the clinical management of cancer. We sought to develop a novel ADC that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells (TIC), which comprise the most aggressive cell population in the tumor. We optimized an anti-5T4 ADC (A1mcMMAF) by sulfydryl-based conjugation of the humanized A1 antibody to the tubulin inhibitor monomethylauristatin F (MMAF) via a maleimidocaproyl linker. A1mcMMAF exhibited potent in vivo antitumor activity in a variety of tumor models and induced long-term regressions for up to 100 days after the last dose. Strikingly, animals showed pathologic complete response in each model with doses as low as 3 mg antibody/kg dosed every 4 days. In a non-small cell lung cancer patient-derived xenograft model, in which 5T4 is preferentially expressed on the less differentiated tumor cells, A1mcMMAF treatment resulted in sustained tumor regressions and reduced TIC frequency. These results highlight the potential of ADCs that target the most aggressive cell populations within tumors, such as TICs. In exploratory safety studies, A1mcMMAF exhibited no overt toxicities when administered to cynomolgus monkeys at doses up to 10 mg antibody/kg/cycle × 2 and displayed a half-life of 5 days. The preclinical efficacy and safety data established a promising therapeutic index that supports clinical testing of A1mcMMAF.

  10. Fabrication of a biofuel cell improved by the π-conjugated electron pathway effect induced from a new enzyme catalyst employing terephthalaldehyde

    Science.gov (United States)

    Chung, Yongjin; Hyun, Kyu Hwan; Kwon, Yongchai

    2015-12-01

    A model explaining the π-conjugated electron pathway effect induced by a novel cross-linker adopted enzyme catalyst is suggested and the performance and stability of an enzymatic biofuel cell (EBC) adopting the new catalyst are evaluated. For this purpose, new terephthalaldehyde (TPA) and conventional glutaraldehyde (GA) cross-linkers are adopted on a glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT)(GOx/PEI/CNT) structure. GOx/PEI/CNT cross-linked by TPA (TPA/[GOx/PEI/CNT]) results in a superior EBC performance and stability to other catalysts. It is attributed to the π bonds conjugated between the aldehyde of TPA and amine of the GOx/PEI molecules. By π conjugation, electrons bonded with carbon and nitrogen are delocalized, promoting the electron transfer and catalytic activity with an excellent EBC performance. The maximum power density (MPD) of an EBC adopting TPA/[GOx/PEI/CNT] (0.66 mW cm-2) is far better than that of the other EBCs (the MPD of EBC adopting GOx/PEI/CNT is 0.40 mW cm-2). Regarding stability, the covalent bonding formed between TPA and GOx/PEI plays a critical role in preventing the denaturation of GOx molecules, leading to an excellent stability. By repeated measurements of the catalytic activity, TPA/[GOx/PEI/CNT] maintains its activity to 92% of its initial value even after five weeks.A model explaining the π-conjugated electron pathway effect induced by a novel cross-linker adopted enzyme catalyst is suggested and the performance and stability of an enzymatic biofuel cell (EBC) adopting the new catalyst are evaluated. For this purpose, new terephthalaldehyde (TPA) and conventional glutaraldehyde (GA) cross-linkers are adopted on a glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT)(GOx/PEI/CNT) structure. GOx/PEI/CNT cross-linked by TPA (TPA/[GOx/PEI/CNT]) results in a superior EBC performance and stability to other catalysts. It is attributed to the π bonds conjugated between the aldehyde of

  11. Non-Fullerene Polymer Solar Cells Based on Alkylthio and Fluorine Substituted 2D-Conjugated Polymers Reach 9.5% Efficiency.

    Science.gov (United States)

    Bin, Haijun; Zhang, Zhi-Guo; Gao, Liang; Chen, Shanshan; Zhong, Lian; Xue, Lingwei; Yang, Changduk; Li, Yongfang

    2016-04-06

    Non-fullerene polymer solar cells (PSCs) with solution-processable n-type organic semiconductor (n-OS) as acceptor have seen rapid progress recently owing to the synthesis of new low bandgap n-OS, such as ITIC. To further increase power conversion efficiency (PCE) of the devices, it is of a great challenge to develop suitable polymer donor material that matches well with the low bandgap n-OS acceptors thus providing complementary absorption and nanoscaled blend morphology, as well as suppressed recombination and minimized energy loss. To address this challenge, we synthesized three medium bandgap 2D-conjugated bithienyl-benzodithiophene-alt-fluorobenzotriazole copolymers J52, J60, and J61 for the application as donor in the PSCs with low bandgap n-OS ITIC as acceptor. The three polymers were designed with branched alkyl (J52), branched alkylthio (J60), and linear alkylthio (J61) substituent on the thiophene conjugated side chain of the benzodithiophene (BDT) units for studying effect of the substituents on the photovoltaic performance of the polymers. The alkylthio side chain, red-shifted absorption down-shifted the highest occupied molecular orbital (HOMO) level and improved crystallinity of the 2D conjugated polymers. With linear alkylthio side chain, the tailored polymer J61 exhibits an enhanced JSC of 17.43 mA/cm(2), a high VOC of 0.89 V, and a PCE of 9.53% in the best non-fullerene PSCs with the polymer as donor and ITIC as acceptor. To the best of our knowledge, the PCE of 9.53% is one of the highest values reported in literature to date for the non-fullerene PSCs. The results indicate that J61 is a promising medium bandgap polymer donor in non-fullerene PSCs.

  12. Hyperthermia-triggered intracellular delivery of anticancer agent to HER2(+) cells by HER2-specific affibody (ZHER2-GS-Cys)-conjugated thermosensitive liposomes (HER2(+) affisomes).

    Science.gov (United States)

    Smith, Brandon; Lyakhov, Ilya; Loomis, Kristin; Needle, Danielle; Baxa, Ulrich; Yavlovich, Amichai; Capala, Jacek; Blumenthal, Robert; Puri, Anu

    2011-07-30

    We previously reported the formulation and physical properties of HER2 (human epidermal growth factor receptor 2)-specific affibody (ZHER2:342-Cys) conjugated thermosensitive liposomes (HER2(+)affisomes). Here we examined localized delivery potential of these affisomes by monitoring cellular interactions, intracellular uptake, and hyperthermia-induced effects on drug delivery. We modified ZHER2:342-Cys by introducing a glycine-serine spacer before the C-terminus cysteine (called ZHER2-GS-Cys) to achieve accessibility to cell surface expressed HER2. This modification did not affect HER2-specific binding and ZHER2-GS-Cys retained its ability to conjugate to the liposomes containing dipalmitoyl phosphatidyl choline: DSPE-PEG2000-Malemide, 96:04 mole ratios (HER2(+)affisomes). HER2(+)affisomes were either (i) fluorescently labeled with rhodamine-PE and calcein or (ii) loaded with an anticancer drug doxorubicin (DOX). Fluorescently labeled HER2(+) affisomes showed at least 10-fold increase in binding to HER2(+) cells (SK-BR-3) when compared to HER2(-) cells (MDA-MB-468) at 37°C. A competition experiment using free ZHER2-GS-Cys blocked HER2(+) affisome-SK-BR-3 cell associations. Imaging with confocal microscopy showed that HER2(+) affisomes accumulated in the cytosol of SK-BR-3 cells at 37°C. Hyperthermia-induced intracellular release experiments showed that the treatment of HER2(+) affisome/SK-BR-3 cell complexes with a 45°C (±1°C) pre-equilibrated buffer resulted in cytosolic delivery of calcein. Substantial calcein release was observed within 20min at 45°C, with no effect on cell viability under these conditions. Similarly, DOX-loaded HER2(+)affisomes showed at least 2- to 3-fold higher accumulation of DOX in SK-BR-3 cells as compared to control liposomes. DOX-mediated cytotoxicity was more pronounced in SK-BR-3 cells especially at lower doses of HER2(+)affisomes. Brief exposure of liposome-cell complexes at 45°C prior to the onset of incubations for cell

  13. Recent advances in polymer solar cells: realization of high device performance by incorporating water/alcohol-soluble conjugated polymers as electrode buffer layer.

    Science.gov (United States)

    He, Zhicai; Wu, Hongbin; Cao, Yong

    2014-02-01

    This Progress Report highlights recent advances in polymer solar cells with special attention focused on the recent rapid-growing progress in methods that use a thin layer of alcohol/water-soluble conjugated polymers as key component to obtain optimized device performance, but also discusses novel materials and device architectures made by major prestigious institutions in this field. We anticipate that due to drastic improvements in efficiency and easy utilization, this method opens up new opportunities for PSCs from various material systems to improve towards 10% efficiency, and many novel device structures will emerge as suitable architectures for developing the ideal roll-to-roll type processing of polymer-based solar cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Antiproliferative Action of Conjugated Linoleic Acid on Human MCF-7 Breast Cancer Cells Mediated by Enhancement of Gap Junctional Intercellular Communication through Inactivation of NF-κB

    Directory of Open Access Journals (Sweden)

    Md. Abdur Rakib

    2013-01-01

    Full Text Available The major conjugated linoleic acid (CLA isomers, c9,t11-CLA and t10,c12-CLA, have anticancer effects; however, the exact mechanisms underlying these effects are unknown. Evidence suggests that reversal of reduced gap junctional intercellular communication (GJIC in cancer cells inhibits cell growth and induces cell death. Hence, we determined that CLA isomers enhance GJIC in human MCF-7 breast cancer cells and investigated the underlying molecular mechanisms. The CLA isomers significantly enhanced GJIC of MCF-7 cells at 40 μM concentration, whereas CLA inhibited cell growth and induced caspase-dependent apoptosis. CLA increased connexin43 (Cx43 expression both at the transcriptional and translational levels. CLA inhibited nuclear factor-κB (NF-κB activity and enhanced reactive oxygen species (ROS generation. No significant difference was observed in the efficacy of c9,t11-CLA and t10,c12-CLA. These results suggest that the anticancer effect of CLA is associated with upregulation of GJIC mediated by enhanced Cx43 expression through inactivation of NF-κB and generation of ROS in MCF-7 cells.

  15. Modulation of oxidative stress by γ-glutamylcysteine (GGC) and conjugated linoleic acid (CLA) isomer mixture in human umbilical vein endothelial cells.

    Science.gov (United States)

    Nakamura, Yukiko K; Dubick, Michael A; Omaye, Stanley T

    2012-06-01

    Individually, γ-glutamylcysteine (GGC), a dipeptide and precursor of glutathione (GSH), and conjugated linoleic acid (CLA), a trans-fatty acid, exhibit antioxidant properties. The objective of this study was to compare effects of co-administration of GGC and CLA to treatment with GGC alone on oxidative stress and GSH synthesis in human endothelial cells. Changes in levels of 8-epi-PGF2α, thiobarbituric acid reactive substances (TBARS), GSH, total antioxidants, GSH synthetase (GSS) expression, and transcription factor DNA binding were assessed in human umbilical vein endothelial cells (HUVEC) treated with GGC alone (100 μmol/L) or combined with CLA isomer mixture (10, 50, 100 μmol/L) for 24h. Significantly higher levels of TBARS, 8-epi-PGF2α, GSH, and GSS protein were found in cells treated with GGC and 10 μmol/L CLA, compared to cells treated with GGC alone, indicative of prooxidant effects of CLA. Approximately 40% cell death was microscopically observed in cells incubated with GGC and 100 μmol/L CLA. Despite lower levels of GSH, treatment with GGC and 50 μmol/L CLA appeared to be protective from oxidative stress similar to treatment with GGC alone, as indicated by lower levels of TBARS, compared to control cells not treated with GGC and CLA.

  16. Potent antigen-specific immune response induced by infusion of spleen cells coupled with succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) conjugated antigens.

    Science.gov (United States)

    Guo, Yixian; Werbel, Tyler; Wan, Suigui; Wu, Haitao; Li, Yaohua; Clare-Salzler, Michael; Xia, Chang-Qing

    2016-02-01

    In the present study, we report our recently developed new approach to inducing antigen-specific immune response. We use two nucleophilic substitution "click" chemistry processes to successfully couple protein antigens or peptides to mouse spleen cells or T cells by a heterobifunctional crosslinker, succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) or sulfo-SMCC. SMCC and its water-soluble analog sulfo-SMCC contain N-hydroxysuccinimide (NHS) ester and maleimide groups, which allow stable covalent conjugation of amine- and sulfhydryl-containing molecules in trans. Protein coupling to cells relies on the free sulfhydryls (thiols) on cell surfaces and the free amines on protein antigens. Although the amount of protein coupled to cells is limited due to the limited number of cell surface thiols, the injection of spleen cells coupled with antigenic proteins, such as keyhole limpet hemocyanin (KLH) or ovalbumin (OVA), induces a potent antigen-specific immune response in vivo, which is even stronger than that induced by the injection of a large dose of protein plus adjuvants. In addition, short peptides coupled to purified splenic T cells also potently elicit peptide-specific T cell proliferation in vivo after injection. Further studies show that antigen-coupled spleen cell treatment leads to augmented IFN-γ-producing T cells. Our study provides a unique antigen delivery method that efficiently distributes antigen to the entire immune system, subsequently eliciting a potent antigen-specific immune response with enhanced IFN-γ production. The findings in the present study suggest that this antigen-cell coupling strategy could be employed in immunotherapy for cancers, infectious diseases as well as immune-mediated disorders.

  17. Measuring mitochondrial and cytoplasmic Ca2+ in EGFP expressing cells with a low-affinity calcium Ruby and its dextran conjugate.

    Science.gov (United States)

    Luccardini, Camilla; Yakovlev, Aleksey V; Pasche, Mathias; Gaillard, Stéphane; Li, Dongdong; Rousseau, France; Ly, Romain; Becherer, Ute; Mallet, Jean-Maurice; Feltz, Anne; Oheim, Martin

    2009-03-01

    The limited choice and poor performance of red-emitting calcium (Ca(2+)) indicators have hampered microfluorometric measurements of the intracellular free Ca(2+) concentration in cells expressing yellow- or green-fluorescent protein constructs. A long-wavelength Ca(2+) indicator would also permit a better discrimination against cellular autofluorescence than the commonly used fluorescein-based probes. Here, we report an improved synthesis and characterization of Calcium Ruby, a red-emitting probe consisting of an extended rhodamine chromophore (578/602 nm peak excitation/emission) conjugated to BAPTA and having an additional NH(2) linker arm. The low-affinity variant (K(D,Ca) approximately 30 microM) with a chloride in meta position that was specifically designed for the detection of large and rapid Ca(2+) transients. While Calcium Ruby is a mitochondrial Ca(2+)probe, its conjugation, via the NH(2) tail, to a 10,000 MW dextran abolishes the sub-cellular compartmentalization and generates a cytosolic Ca(2+) probe with an affinity matched to microdomain Ca(2+) signals. As an example, we show depolarization-evoked Ca(2+) signals triggering the exocytosis of individual chromaffin granules. Calcium Ruby should be of use in a wide range of applications involving dual- or triple labeling schemes or targeted sub-cellular Ca(2+) measurements.

  18. High Performance Small-Molecule Cathode Interlayer Materials with D-A-D Conjugated Central Skeletons and Side Flexible Alcohol/Water-Soluble Groups for Polymer Solar Cells.

    Science.gov (United States)

    Han, Jianxiong; Chen, Youchun; Chen, Weiping; Yu, Chengzhuo; Song, Xiaoxian; Li, Fenghong; Wang, Yue

    2016-12-07

    A new class of organic cathode interfacial layer (CIL) materials based on isoindigo derivatives (IID) substituted with pyridinium or sulfonate zwitterion groups were designed, synthesized, and applied in polymer solar cells (PSCs) with PTB7:PC71BM (PTB7: polythieno[3,4-b]-thiophene-co-benzodithiophene and PC71BM: [6,6]-phenyl C71-butyric acidmethyl ester) as an active layer. Compared with the control device, PSCs with an IID-based CIL show simultaneous enhancement of open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF). Systematic optimizations of the central conjugated core and side flexible alcohol-soluble groups demonstrated that isoindigo-based CIL material with thiophene and sulfonate zwitterion substituent groups can efficiently enhance the PSC performance. The highest power conversion efficiency (PCE) of 9.12%, which is 1.75 times that of the control device without CIL, was achieved for the PSC having an isoindigo-based CIL. For the PSCs with an isoindigo-based CIL, the molecule-dependent performance property studies revealed that the central conjugated core with D-A-D characteristics and the side chains with sulfonate zwitterions groups represents an efficient strategy for constructing high performance CILs. Our study results may open a new avenue toward high performance PSCs.

  19. 2-Amino-2-deoxy-glucose conjugated cobalt ferrite magnetic nanoparticle (2DG-MNP) as a targeting agent for breast cancer cells.

    Science.gov (United States)

    Aşık, Elif; Aslan, Tuğba Nur; Volkan, Mürvet; Güray, N Tülin

    2016-01-01

    In this study, 2-amino-2-deoxy-glucose (2DG) was conjugated to COOH modified cobalt ferrite magnetic nanoparticles (COOH-MNPs), which were designed to target tumor cells as a potential targetable drug/gene delivery agent for cancer treatment. According to our results, it is apparent that, 2DG labeled MNPs were internalized more efficiently than COOH-MNPs under the same conditions in all cell types (MDA-MB-231 and MCF-7 cancer and MCF-10A normal breast cells) (p<0.001). Moreover, the highest amount of uptake was observed in MDA-MB-231, followed by MCF-7 and normal MCF-10A cells for both MNPs. The apoptotic effects of 2DG-MNPs were further evaluated, and it was found that apoptosis was not induced at low concentrations of 2DG-MNPs in all cell types, whereas dramatic cell death was observed at higher concentrations. In addition, the gene expression levels of four drug-metabolizing enzymes, two Phase I (CYP1A1, CYP1B1) and two Phase II (GSTM3, GSTZ1) were also increased with the high concentrations of 2DG-MNPs. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Specific targeting of nasopharyngeal carcinoma cell line CNE1 by C225-conjugated ultrasmall superparamagnetic iron oxide particles with magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Dongbo Lin; Chunli Chen; Guangyuaa Hu; Qi Mei; Hong Qiu; Guoxian Long; Guoqing Hu

    2011-01-01

    An accurate definition of clinical target volume (CTV) is essential for the application of radiotherapy in nasopharvngeai carcinoma (NPC) treatment. A novel epidermal growth factor receptor (EGFR)-targeting contrast agent (C225-USPIO) was designed by conjugating ultrasmail superparamagnetic iron oxide (USPIO) nanoparticles with cetuximab (C225), to non-invasively define the CTV of tumor. The immunobinding activity of C225-USPIO to NPC cell line CNEI was confirmed by flow cytometry and immunofluorescence. The time-dependent accumulation of C225-USPIO in CNE1 cells was evaluated using Prussian blue staining. Targeted internalization and subcellular localization of C225-USPIO was confirmed by transmission electron microscope. The results indicated that C225-USPIO specifically bound to EGFR on the surface of CNEI cells and was taken up into the cell. The uptake of C225-USPIO by CNE1 cells increased significantly with time, when compared with human IgG-USPIO. In addition, 4.7 T magnetic resonance imaging (MRI) revealed that C225-USPIO had a capacity to accumulate in the CNE1 cells, with a resultant marked decrease in MRI T2-weighted signal intensity over time. These findings imply that C225-USPIO has the potential as an MRI contrast agent and can be employed to non-invasively detect early-stage NPC with EGFR overexpression. This provides sufficient theoretical basis for commencing in vivo experiments with the compound.

  1. Revisiting conjugate schedules.

    Science.gov (United States)

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed.

  2. A pyrene-benzthiazolium conjugate portraying aggregation induced emission, a ratiometric detection and live cell visualization of HSO{sub 3}{sup −}

    Energy Technology Data Exchange (ETDEWEB)

    Diwan, Uzra; Kumar, Virendra [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India); Mishra, Rakesh K. [Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR–National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019 (India); Rana, Nishant Kumar; Koch, Biplob; Singh, Manish Kumar [Department of Zoology (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Upadhyay, K.K., E-mail: drkaushalbhu@yahoo.co.in [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India)

    2016-07-27

    The present study deals with the photophysical property of a pyrene-benzthiazolium conjugate R1, as a strong intramolecular charge transfer (ICT) probe exhibiting long wavelength emission in the red region. Unlike traditional planar polyaromatic hydrocarbons whose aggregation generally quenches the light emission, the pyrene based R1 was found to display aggregation-induced emission (AIE) property along with simultaneous increase in its quantum yield upon increasing the water content of the medium. The R1 exhibits high specificity towards HSO{sub 3}{sup −}/SO{sub 3}{sup 2−} by interrupting its own ICT producing there upon a large ratiometric blue shift of ∼220 nm in its emission spectrum. The lowest detection limit for the above measurement was found to be 8.90 × 10{sup −8} M. The fluorescent detection of HSO{sub 3}{sup −} was also demonstrated excellently by test paper strip and silica coated TLC plate incorporating R1. The live cell imaging of HSO{sub 3}{sup −} through R1 in HeLa cells was studied using fluorescence microscopic studies. The particle size and morphological features of R1 and R1-HSO{sub 3}{sup −} aggregates in aqueous solution were characterized by DLS along with SEM analysis.- Highlights: • A pyrene-benzthiazolium conjugate probe (R1) itself showed interesting phenomenon of an aggregation-induced emission (AIE). • R1 emits in the red channel and effectively utilized as a colorimetric and ratiometric fluorescent sensor for HSO{sub 3}{sup −}. • The nano-dimensional spherical particles of R1 got enlarged upon its interaction with the HSO{sub 3}{sup −}. • R1 can efficiently stain HSO{sub 3}{sup −} in live cells and can be used for the on-spot detection of the same.

  3. Poly(lactic-co-glycolic acid nanoparticles conjugated with CD133 aptamers for targeted salinomycin delivery to CD133+ osteosarcoma cancer stem cells

    Directory of Open Access Journals (Sweden)

    Ni MZ

    2015-03-01

    Full Text Available Miaozhong Ni,1,* Min Xiong,1,* Xinchao Zhang,1,* Guoping Cai,1 Huaiwen Chen,2 Qingmin Zeng,1 Zuochong Yu1 1Department of Orthopedics, Jinshan Hospital, Fudan University, 2International Joint Cancer Institute, the Second Military Medical University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cancer stem cells (CSCs possess the characteristics associated with normal stem cells and are responsible for cancer initiation, recurrence, and metastasis. CD133 is regarded as a CSCs marker of osteosarcoma, which is the most common primary bone malignancy in childhood and adolescence. Salinomycin, a polyether ionophore antibiotic, has been shown to kill various CSCs, including osteosarcoma CSCs. However, salinomycin displayed poor aqueous solubility that hinders its clinical application. The objective of this study was to develop salinomycin-loaded nanoparticles to eliminate CD133+ osteosarcoma CSCs.Methods: The salinomycin-loaded PEGylated poly(lactic-co-glycolic acid nanoparticles (SAL-NP conjugated with CD133 aptamers (Ap-SAL-NP were developed by an emulsion/solvent evaporation method, and the targeting and cytotoxicity of Ap-SAL-NP to CD133+ osteosarcoma CSCs were evaluated.Results: The nanoparticles are of desired particle size (~150 nm, drug encapsulation efficiency (~50%, and drug release profile. After 48 hours treatment of the Saos-2 CD133+ osteosarcoma cells with drugs formulated in Ap-SAL-NP, SAL-NP, and salinomycin, the concentrations needed to kill 50% of the incubated cells were found to be 2.18, 10.72, and 5.07 µg/mL, respectively, suggesting that Ap-SAL-NP could be 4.92 or 2.33 fold more effective than SAL-NP or salinomycin, respectively. In contrast, Ap-SAL-NP was as effective as SAL-NP, and less effective than salinomycin in Saos-2 CD133- cells, suggesting that Ap-SAL-NP possess specific cytotoxicity toward Saos-2 CD133+ cells. Ap-SAL-NP showed the best therapeutic effect in Saos-2

  4. Detection of Cancer Cell Death Mediated by a Synthetic Granzyme B-like Peptide Fluorescent Conjugate and the same Peptide Binding in Bacteria.

    Science.gov (United States)

    Lo, Wai Chun Jennifer; Luther, Donald Gene

    2014-03-01

    Granzyme-mediated apoptosis, supported by pore-forming perforin, plays an important role in CD8+ T lymphocytes (CTL)-dependent cellular immunity protection against both cancer and viral infection. Quantitative and qualitative problems with CTL are potential contributing factors to disease progression. The feasibility of developing CTL-independent cellular immunity is desired but must first overcome the barrier of CTL-independent target cell recognition. Granzyme B with its strong pro-apoptotic activity in many different target cells is investigated for use in the CTL-independent cellular immunity approach, and granzyme B or its bioactive peptides without the enzymatic activity are more desirable for use. Native granzyme B with enzymatic activity is usually investigated in cancer cells for its mediation of apoptosis by detection of DNA fragmentation. Detection of cell death mediated by such peptides in cancer cells is needed to demonstrate the potential therapeutic purposes. We show with never-before-seen microscopic images using fluorescence microscopy that a synthetic granzyme B-like peptide fluorescent conjugate (GP1R) can: 1) mediate cell death of different cancer cells via membrane extrusion, 2) bind to constitutively expressed binding targets in different cancer cells and bacteria, and 3) promote bacterial phagocytosis. The putative binding targets may serve as a universal pathologic biomarker detectable by GP1R. Our data taken together demonstrate the potential applications of GP1R for use in CTL-independent target cell recognition and target cell death induction. It may lead to development of rapid targeted detection and new treatment of cancer, viral and bacterial infections. The new treatment may show mutual benefits for two or more diseases.

  5. Depicting Binding-Mediated Translocation of HIV-1 Tat Peptides in Living Cells with Nanoscale Pens of Tat-Conjugated Quantum Dots

    Science.gov (United States)

    Lin, Chien Y.; Huang, Jung Y.; Lo, Leu-Wei

    2017-01-01

    Cell-penetrating peptides (CPPs) can translocate across cell membranes, and thus have great potential for the cellular delivery of macromolecular cargoes. However, the mechanism of this cellular uptake process is not yet fully understood. In this study, a time-lapse single-particle light-sheet microscopy technique was implemented to obtain a parallel visualization of the translocating process of individual human immunodeficiency virus 1 (HIV-1) transactivator of transcription (Tat) peptide conjugated quantum dots (TatP-QDs) in complex cellular terrains. Here, TatP-QDs served as nanoscale dynamic pens, which depict remarkable trajectory aggregates of TatP-QDs on the cell surface. Spectral-embedding analysis of the trajectory aggregates revealed a manifold formed by isotropic diffusion and a fraction of directed movement, possibly caused by interaction between the Tat peptides and heparan sulfate groups on the plasma membrane. Further analysis indicated that the membrane deformation induced by Tat-peptide attachment increased with the disruption of the actin framework in cytochalasin D (cyto D)-treated cells, yielding higher interactions on the TatP-QDs. In native cells, the Tat peptides can remodel the actin framework to reduce their interaction with the local membrane environment. Characteristic hot spots for interaction were detected on the membrane, suggesting that a funnel passage may have formed for the Tat-coated particles. This finding offers valuable insight into the cellular delivery of nanoscale cargo, suggesting an avenue for direct therapeutic delivery. PMID:28208588

  6. DFT theoretical investigations of π-conjugated molecules based on thienopyrazine and different acceptor moieties for organic photovoltaic cells

    Directory of Open Access Journals (Sweden)

    Mohammed Bourass

    2016-09-01

    Full Text Available In this work, theoretical study by using the DFT method on eleven conjugated compounds based on thienopyrazine is reported. Different electron side groups were introduced to investigate their effects on the electronic structure; The HOMO, LUMO and Gap energy of these compounds have been calculated and reported in this paper. A systematic theoretical study of such compound has not been reported as we know. Thus, our aim is first, to explore their electronic and spectroscopic properties on the basis of the DFT quantum chemical calculations. Second, we are interested to elucidate the parameters that influence the photovoltaic efficiency toward better understanding of the structure–property relationships. The study of structural, electronic and optical properties for these compounds could help to design more efficient functional photovoltaic organic materials.

  7. Design, synthesis and application of a π-conjugated, non-spiro molecular alternative as hole-transport material for highly efficient dye-sensitized solar cells and perovskite solar cells

    Science.gov (United States)

    Liu, Peng; Xu, Bo; Hua, Yong; Cheng, Ming; Aitola, Kerttu; Sveinbjörnsson, Kári; Zhang, Jinbao; Boschloo, Gerrit; Sun, Licheng; Kloo, Lars

    2017-03-01

    Two low-cost, easily synthesized π-conjugated molecules have been applied as hole-transport materials (HTMs) for solid state dye-sensitized solar cells (ssDSSCs) and perovskite solar cells (PSCs). For X1-based devices, high power conversion efficiencies (PCEs) of 5.8% and 14.4% in ssDSSCs and PSCs has been demonstrated. For X14-based devices, PCEs were improved to 6.1% and 16.4% in ssDSCs and PSCs, respectively.

  8. A smart tumor targeting peptide-drug conjugate, pHLIP-SS-DOX: synthesis and cellular uptake on MCF-7 and MCF-7/Adr cells.

    Science.gov (United States)

    Song, Qin; Chuan, Xingxing; Chen, Binlong; He, Bing; Zhang, Hua; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang

    2016-06-01

    Doxorubicin (DOX) is a potent anticancer drug for the treatment of tumors, but the poor specificity and multi-drug resistance (MDR) on tumor cells have restricted its application. Here, a pH and reduction-responsive peptide-drug conjugate (PDC), pHLIP-SS-DOX, was synthesized to overcome these drawbacks. pH low insertion peptide (pHLIP) is a cell penetrating peptide (CPP) with pH-dependent transmembrane ability. And because of the unique cell membrane insertion pattern, it might reverse the MDR. The cellular uptake study showed that on both drug-sensitive MCF-7 and drug-resistant MCF-7/Adr cells, pHLIP-SS-DOX obviously facilitated the uptake of DOX at pH 6.0 and the uptake level on MCF-7/Adr cells was similar with that on MCF-7 cells, indicating that pHLIP-SS-DOX had the ability to target acidic tumor cells and reverse MDR. In vitro cytotoxicity study mediated by GSH-OEt demonstrated that the cytotoxic effect of pHLIP-SS-DOX was reduction responsive, with obvious cytotoxicity at pH 6.0; while it had poor cytotoxicity at pH 7.4, no matter with or without GSH-OEt pretreatment. This illustrated that pHLIP could deliver DOX into tumor cells with acidic microenvironment specifically and could not deliver drugs into normal cells with neutral microenvironment. In summary, pHLIP-SS-DOX is a promising strategy to target drugs to tumors and provides a possibility to overcome MDR.

  9. Potentiation of mitochondrial dysfunction in tumor cells by conjugates of metabolic modulator dichloroacetate with a Pt(IV) derivative of oxaliplatin.

    Science.gov (United States)

    Zajac, Juraj; Kostrhunova, Hana; Novohradsky, Vojtech; Vrana, Oldrich; Raveendran, Raji; Gibson, Dan; Kasparkova, Jana; Brabec, Viktor

    2016-03-01

    The molecular and cellular mechanisms of enhanced toxic effects in tumor cells of the Pt(IV) derivatives of antitumor oxaliplatin containing axial dichloroacetate (DCA) ligands were investigated. DCA ligands were chosen because DCA has shown great potential as an apoptosis sensitizer and anticancer agent reverting the Wartburg effect. In addition, DCA reverses mitochondrial changes in a wide range of cancers, promoting tumor cell apoptosis in a mitochondrial-dependent pathway. We demonstrate that (i) the transformation of oxaliplatin to its Pt(IV) derivatives containing axial DCA ligands markedly enhances toxicity in cancer cells and helps overcome inherent and acquired resistance to cisplatin and oxaliplatin; (ii) a significant fraction of the intact molecules of DCA conjugates with Pt(IV) derivative of oxaliplatin accumulates in cancer cells where it releases free DCA; (iii) mechanism of biological action of the Pt(IV) derivatives of oxaliplatin containing DCA ligands is connected with the effects of DCA released in cancer cells from the Pt(IV) prodrugs on mitochondria and metabolism of glucose; (iv) treatments with the Pt(IV) derivatives of oxaliplatin containing DCA ligands activate an autophagic response in human colorectal cancer cells; (v) the toxic effects in cancer cells of the Pt(IV) derivatives of oxaliplatin containing DCA ligands can be potentiated if cells are treated with these prodrugs in combination with 5-fluorouracil. These properties of the Pt(IV) derivatives of oxaliplatin containing DCA ligands provide opportunities for further development of new platinum-based agents with the capability of killing cancer cells resistant to conventional antitumor platinum drugs used in the clinic.

  10. Involvement of PPAR gamma and E-cadherin/beta-catenin pathway in the antiproliferative effect of conjugated linoleic acid in MCF-7 cells.

    Science.gov (United States)

    Bocca, Claudia; Bozzo, Francesca; Francica, Simona; Colombatto, Sebastiano; Miglietta, Antonella

    2007-07-15

    Conjugated linoleic acid (CLA) is a naturally occurring fatty acid, which has been shown to exert beneficial effects against breast carcinogenesis. It has been reported that CLA could modulate cellular proliferation and differentiation through the activation of peroxisome proliferator-activated receptors (PPARs). Among different PPAR isotypes, PPAR gamma is involved in growth inhibition of transformed cells. Ligands of PPAR gamma are considered as potential anticancer drugs, so CLA was tested for its ability to induce PPAR gamma expression in MCF-7 breast cancer cells. The effects of CLA and of a specific synthetic PPAR gamma antagonist were evaluated on cell growth as well as on parameters responsible for cell growth regulation. We demonstrated here that CLA stimulated the expression of PPAR gamma to levels up to control and caused PPAR gamma translocation into the nucleus. Furthermore, the overexpression of PPAR gamma positively correlates with the inhibition of cell proliferation and with the modulation of ERK signaling induced by CLA; in all cases the administration of the antagonist reverted CLA effects. The PPAR-signaling pathway is connected with the beta-catenin/E-cadherin pathway, thus we evaluated CLA effects on the expression and cellular distribution of these proteins, which are involved in cell adhesion and responsible for invasive behavior. The treatment with CLA determined the up-regulation and the redistribution of beta-catenin and E-cadherin and the antagonist reverted only the effect on beta-catenin. These studies indicate that CLA regulates PPAR gamma expression by selectively acting as an agonist and may influence cell-cell adhesion and invasiveness of MCF-7 cells. (c) 2007 Wiley-Liss, Inc.

  11. Novel Two-Dimensional Conjugated Polymer Containing Fluorinated Bithiophene as Donor and Benzoselenodiazole as Acceptor Units with Vinyl-Terthiophene Pendants for Polymer Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Rathinam Raja

    2017-07-01

    Full Text Available Novel two-dimensional conjugated copolymer, abbreviated as PDTBSeVTT-2TF, containing electron-deficient 4,7-di(thiophen-2-ylbenzo[c][1,2,5]selenodiazole (DTBSe unit, conjugated vinyl-terthiophene (VTT side chain and 3,3′-difluoro-2,2′-bithiophene (2TF was designed and synthesized using microwave-assisted Stille cross-coupling polymerization. UV–visible absorption and cyclic voltammetry studies revealed that this copolymer possesses a strong and broad absorption in the range of 300–800 nm and a narrow optical bandgap (Eg of 1.57 eV with low-lying HOMO and LUMO energy levels. Further, the bulk heterojunction polymer solar cells (PSCs were fabricated using PDTBSeVTT-2TF as donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM as acceptor with an inverted device structure of ITO/ZnO/PDTBSeVTT-2TF:PC71BM/V2O5/Ag. The processing temperature of blend solution for preparing PDTBSeVTT-2TF:PC71BM active layer showed obvious impact on the photovoltaic performance of solar devices. The cell fabricated from the blend solution at 65 °C exhibited enhanced power conversion efficiencies (PCE of 5.11% with a Jsc of 10.99 mA/cm−2 compared with the one at 50 °C, which had a PCE of 4.69% with a Jsc of 10.10 mA/cm−2. This enhancement is due to the dissolution of PDTBSeVTT-2TF clusters into single molecules and small aggregates, improving the miscibility between the polymer and PC71BM and thus increasing the donor/acceptor interface.

  12. The influence of the push-pull effect and a π-conjugated system in conversion efficiency of bis-chalcone compounds in a dye sensitized solar cell

    Science.gov (United States)

    Teo, Kien Yung; Tiong, Mee Hing; Wee, Hung Yee; Jasin, Nornadia; Liu, Zhi-Qiang; Shiu, Ming Yang; Tang, Jyun Yang; Tsai, Jenn-Kai; Rahamathullah, Rafizah; Khairul, Wan M.; Tay, Meng Guan

    2017-09-01

    Chalcone and its related compounds are known to be π-conjugated compounds, which can be potentially used in different electronic areas include dye sensitized solar cell (DSSC). A total of six bis-chalcone compounds (1-6) have been synthesized using a Claisen-Schmidt condensation method under basic conditions. The compounds were used as the dye in DSSC to test their solar conversion efficiency. In the process of solar cell fabrication, titanium(II) oxide (TiO2) coated glass was used as the working electrode, whereas the mixture of iodine (I2), lithium iodide (LiI), 4-tertbutylpyridine (4-TBP) and 1,2-dimethyl-3-propylimidazolium (DMPII) in 3-methoxypropionitrile were used as the electrolyte. The DSSC was fabricated by immersing the TiO2 glass into the respective bis-chalcone compound solution and dried into the oven at 45 °C for 120 min. Lastly, the working electrode and counter electrode were sealed using surlyn of 60 μm thickness. The efficiency test was conducted under AM 1.5G illumination with the incident light intensity of 100 mW/cm2. Among the six bis-chalcone derivatives, compound 2, namely 1,4-bis-2-hydroxychalcone, was recorded with the highest efficiency (0.054%) compared to the others (0.022-0.035%). The presence of a π-conjugated system and the push-pull effect in the molecule were found to enhance the conversion efficiency of DSSC. Details of the results are discussed in the present paper.

  13. Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer-based Solar Cells. Time-Resolved Microwave Conductivity and Theory

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Jordan C. [Univ. of California, Los Angeles, CA (United States); Arntsen, Christopher D. [Univ. of California, Los Angeles, CA (United States); Hernandez, Samuel [Univ. of California, Los Angeles, CA (United States); Huber, Rachel [Univ. of California, Los Angeles, CA (United States); Nardes, Alexandre M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Halim, Merissa [Univ. of California, Los Angeles, CA (United States); Kilbride, Daniel [Univ. of California, Los Angeles, CA (United States); Rubin, Yves [Univ. of California, Los Angeles, CA (United States); Tolbert, Sarah H. [Univ. of California, Los Angeles, CA (United States); Kopidakis, Nikos [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schwartz, Benjamin J. [Univ. of California, Los Angeles, CA (United States); Neuhauser, Daniel [Univ. of California, Los Angeles, CA (United States)

    2013-09-23

    The efficiency of bulk heterojunction (BHJ) organic photovoltaics is sensitive to the morphology of the fullerene network that transports electrons through the device. This sensitivity makes it difficult to distinguish the contrasting roles of local electron mobility (how easily electrons can transfer between neighboring fullerene molecules) and macroscopic electron mobility (how well-connected is the fullerene network on device length scales) in solar cell performance. In this work, a combination of density functional theory (DFT) calculations, flash-photolysis time-resolved microwave conductivity (TRMC) experiments, and space-charge-limit current (SCLC) mobility estimates are used to examine the roles of local and macroscopic electron mobility in conjugated polymer/fullerene BHJ photovoltaics. The local mobility of different pentaaryl fullerene derivatives (so-called ‘shuttlecock’ molecules) is similar, so that differences in solar cell efficiency and SCLC mobilities result directly from the different propensities of these molecules to self-assemble on macroscopic length scales. These experiments and calculations also demonstrate that the local mobility of phenyl-C60 butyl methyl ester (PCBM) is an order of magnitude higher than that of other fullerene derivatives, explaining why PCBM has been the acceptor of choice for conjugated polymer BHJ devices even though it does not form an optimal macroscopic network. The DFT calculations indicate that PCBM's superior local mobility comes from the near-spherical nature of its molecular orbitals, which allow strong electronic coupling between adjacent molecules. In combination, DFT and TRMC techniques provide a tool for screening new fullerene derivatives for good local mobility when designing new molecules that can improve on the macroscopic electron mobility offered by PCBM.

  14. MRP2, a human conjugate export pump, is present and transports fluo 3 into apical vacuoles of Hep G2 cells.

    Science.gov (United States)

    Cantz, T; Nies, A T; Brom, M; Hofmann, A F; Keppler, D

    2000-04-01

    The multidrug resistance protein 2 (MRP2, symbol ABCC2) transports anionic conjugates and certain amphiphilic anions across the apical membrane of polarized cells. Human hepatoma Hep G2 cells retain hepatic polarity and form apical vacuoles into which cholephilic substances are secreted. Immunofluorescence microscopy showed that human MRP2 was expressed in the apical vacuole membrane of polarized Hep G2 cells, whereas the isoform MRP3 was localized to the lateral membrane. Expression of both MRP2 and MRP3 was confirmed by immunoblotting and reverse transcription PCR. Fluo 3 secretion into the apical vacuoles was inhibited by cyclosporin A but not by selective inhibitors of multidrug resistance 1 P-glycoprotein. In addition, carboxyfluorescein, rhodamine 123, and the fluorescent bile salt derivatives ursodeoxycholyl-(Nepsilon-nitrobenzoxadiazolyl)-lysine and cholylglycylamido-fluorescein were secreted into the apical vacuoles; the latter two probably via the bile salt export pump. We conclude that MRP2 mediates fluo 3 secretion into the apical vacuoles of polarized Hep G2 cells. Thus the function of human MRP2 and the action of inhibitors can be analyzed by the secretion of fluorescent anions such as fluo 3.

  15. Design and synthesis of new benzimidazole-carbazole conjugates for the stabilization of human telomeric DNA, telomerase inhibition, and their selective action on cancer cells.

    Science.gov (United States)

    Maji, Basudeb; Kumar, Krishan; Kaulage, Mangesh; Muniyappa, K; Bhattacharya, Santanu

    2014-08-28

    Cell-permeable small molecules that enhance the stability of the G-quadruplex (G4) DNA structures are currently among the most intensively pursued ligands for inhibition of the telomerase activity. Herein we report the design and syntheses of four novel benzimidazole-carbazole conjugates and demonstrate their high binding affinity to G4 DNA. S1 nuclease assay confirmed the ligand mediated G-quadruplex DNA protection. Additional evidence from Telomeric Repeat Amplification Protocol (TRAP-LIG) assay demonstrated efficient telomerase inhibition activity by the ligands. Two of the ligands showed IC50 values in the sub-micromolar range in the TRAP-LIG assay, which are the best among the benzimidazole derivatives reported so far. The ligands also exhibited cancer cell selective nuclear internalization, nuclear condensation, fragmentation, and eventually antiproliferative activity in long-term cell viability assays. Annexin V-FITC/PI staining assays confirm that the cell death induced by the ligands follows an apoptotic pathway. An insight into the mode of ligand binding was obtained from the molecular dynamics simulations.

  16. Bare and protein-conjugated Fe3O4 ferromagnetic nanoparticles for utilization in magnetically assisted hemodialysis: biocompatibility with human blood cells

    Science.gov (United States)

    Stamopoulos, D.; Manios, E.; Gogola, V.; Benaki, D.; Bouziotis, P.; Niarchos, D.; Pissas, M.

    2008-12-01

    Magnetically assisted hemodialysis is a development of conventional hemodialysis and is based on the circulation of ferromagnetic nanoparticle-targeted binding substance conjugates (FN-TBS Cs) in the bloodstream of the patient and their eventual removal by means of a 'magnetic dialyzer'. Presented here is an in vitro investigation on the biocompatibility of bare Fe3O4 FNs and Fe3O4-bovine serum albumin Cs with blood cells, namely red blood cells (RBCs), white blood cells (WBCs) and platelets (Plts). Atomic force microscopy (AFM) and optical microscopy (OM) enabled the examination of blood cells at the nanometer and micrometer level, respectively. The observations made on FN- and C-maturated blood samples are contrasted to those obtained on FN- and C-free reference blood samples subjected to exactly the same maturation procedure. Qualitatively, both AFM and OM revealed no changes in the overall shape of RBCs, WBCs and Plts. Incidents where bare FNs or Cs were bound onto the surface of RBCs or internalized by WBCs were very rare. Detailed examination by means of OM proved that impaired coagulation of Plts is not initiated/promoted either by FNs or Cs. Quantitatively, the statistical analysis of the obtained AFM images from RBC surfaces clearly revealed that the mean surface roughness of RBCs maturated with bare FNs or Cs was identical to the one of reference RBCs.

  17. Melphalan Alone or Conjugated to a Follicle Stimulating Hormone-β Peptide Kills Murine Testicular Cells in vitro and Transiently Suppresses Murine Spermatogenesis in vivo

    OpenAIRE

    Amory, John K.; Hong, Sungwoo; Yu, Xiaozhong; Muller, Charles H; Faustman, Elaine; Goldstein, Alex

    2014-01-01

    New approaches to sterilizing male animals are needed to control captive and wild animal populations. We sought to develop a non-surgical method of permanent sterilization for male animals by administering the gonadotoxicant melphalan conjugated to peptides derived from the β-chain of follicle stimulating hormone (FSHβ). We hypothesized that conjugating melphalan to FSHβ peptides would magnify the gonadotoxic effects of melphalan while minimizing systemic toxicity. The ability of conjugates o...

  18. Inhibition of proliferation and survival of diffuse large B-cell lymphoma cells by a small-molecule inhibitor of the ubiquitin-conjugating enzyme Ubc13-Uev1A.

    Science.gov (United States)

    Pulvino, Mary; Liang, Yue; Oleksyn, David; DeRan, Michael; Van Pelt, Elise; Shapiro, Joel; Sanz, Ignacio; Chen, Luojing; Zhao, Jiyong

    2012-08-23

    Diffuse large B-cell lymphoma (DLBCL), the most common type of non-Hodgkin lymphoma, remains a partially curable disease. Genetic alterations affecting components of NF-κB signaling pathways occur frequently in DLBCL. Almost all activated B cell-like (ABC) DLBCL, which is the least curable group among the 3 major subtypes of this malignancy, and a substantial fraction of germinal center B cell-like (GCB) DLBCL exhibit constitutive NF-κB pathway activity. It has been demonstrated that ABC-DLBCL cells require such activity for proliferation and survival. Therefore, inhibition of NF-κB activation in DLBCL may provide an efficient and targeted therapy. In screening for small-molecule compounds that may inhibit NF-κB activation in DLBCL cells, we identified a compound, NSC697923, which inhibits the activity of the ubiquitin-conjugating (E2) enzyme Ubc13-Uev1A. NSC697923 impedes the formation of the Ubc13 and ubiquitin thioester conjugate and suppresses constitutive NF-κB activity in ABC-DLBCL cells. Importantly, NSC697923 inhibits the proliferation and survival of ABC-DLBCL cells and GCB-DLBCL cells, suggesting the Ubc13-Uev1A may be crucial for DLBCL growth. Consistently, knockdown of Ubc13 expression also inhibited DLBCL cell survival. The results of the present study indicate that Ubc13-Uev1A may represent a potential therapeutic target in DLBCL. In addition, compound NSC697923 may be exploited for the development of DLBCL therapeutic agents.

  19. Hybrid electronics and electrochemistry with conjugated polymers.

    Science.gov (United States)

    Inganäs, Olle

    2010-07-01

    In this critical review, we discuss the history and development of polymer devices wherein manipulation of the electronic conductivity by electrochemical redox processes in a conjugated polymer is used to form new functions. The devices employed are an electrochemical transistor, an electrolyte-gated field-effect transistor and light-emitting electrochemical cells, all of which combine doping/undoping of a conjugated polymer with modification of electronic transport (130 references).

  20. D-π-A-π-A Strategy to Design Benzothiadiazole-carbazole-based Conjugated Polymer with High Solar Cell Voltage and Enhanced Photocurrent.

    Science.gov (United States)

    Zhou, Manxi; Wang, Min; Zhu, Lei; Yang, Zhenqing; Jiang, Chao; Cao, Dapeng; Li, Qifang

    2015-12-01

    The theoretical calculations are used to find that D-π-A-π-A style conjugated polymer PC-TBTBT is more efficient for solar cells application than the D-π-A analog PC-TBT because the D-π-A-π-A structure has a narrower band gap and higher molar absorption coefficient and redshift spectrum. Motivated by the theoretical prediction, 5,6-bis(octyloxy)-2,1,3-benzothiadiazole and 2,7-carbazole are adopted to synthesize the D-π-A-π-A style PC-TBTBT (M(w) = 31.1 kDa) and D-π-A analog PC-TBT (M(w) = 87.5 kDa) by Suzuki coupling reaction. Experimental results confirm that D-π-A-π-A PC-TBTBT-based solar cell shows a power conversion efficiency (PCE) of 4.74% with high V(OC) of 0.99 V and enhanced J(SC) of 9.70 mA cm(-2). The PCE and J(SC) achieve improvements of 17% and 26%, respectively, compared to the D-π-A PC-TBT-based solar cell.

  1. Synthesis of tumor-targeted folate conjugated fluorescent magnetic albumin nanoparticles for enhanced intracellular dual-modal imaging into human brain tumor cells.

    Science.gov (United States)

    Wang, Xueqin; Tu, Miaomiao; Tian, Baoming; Yi, Yanjie; Wei, ZhenZhen; Wei, Fang

    2016-11-01

    Superparamagnetic iron oxide nanoparticles (SPIO NPs), utilized as carriers are attractive materials widely applied in biomedical fields, but target-specific SPIO NPs with lower toxicity and excellent biocompatibility are still lacking for intracellular visualization in human brain tumor diagnosis and therapy. Herein, bovine serum albumin (BSA) coated superparamagnetic iron oxide, i.e. γ-Fe2O3 nanoparticles (BSA-SPIO NPs), are synthesized. Tumor-specific ligand folic acid (FA) is then conjugated onto BSA-SPIO NPs to fabricate tumor-targeted NPs, FA-BSA-SPIO NPs as a contrast agent for MRI imaging. The FA-BSA-SPIO NPs are also labeled with fluorescein isothiocyanate (FITC) for intracellular visualization after cellular uptake and internalization by glioma U251 cells. The biological effects of the FA-BSA-SPIO NPs are investigated in human brain tumor U251 cells in detail. These results show that the prepared FA-BSA-SPIO NPs display undetectable cytotoxicity, excellent biocompatibility, and potent cellular uptake. Moreover, the study shows that the made FA-BSA-SPIO NPs are effectively internalized for MRI imaging and intracellular visualization after FITC labeling in the targeted U251 cells. Therefore, the present study demonstrates that the fabricated FITC-FA-BSA-SPIO NPs hold promising perspectives by providing a dual-modal imaging as non-toxic and target-specific vehicles in human brain tumor treatment in future.

  2. Antigen processing of glycoconjugate vaccines; the polysaccharide portion of the pneumococcal CRM(197) conjugate vaccine co-localizes with MHC II on the antigen processing cell surface.

    Science.gov (United States)

    Lai, Zengzu; Schreiber, John R

    2009-05-21

    Pneumococcal (Pn) polysaccharides (PS) are T-independent (TI) antigens and do not induce immunological memory or antibodies in infants. Conjugation of PnPS to the carrier protein CRM(197) induces PS-specific antibody in infants, and memory similar to T-dependent (Td) antigens. Conjugates have improved immunogenicity via antigen processing and presentation of carrier protein with MHC II and recruitment of T cell help, but the fate of the PS attached to the carrier is unknown. To determine the location of the PS component of PnPS-CRM(197) in the APC, we separately labeled PS and protein and tracked their location. The PS of types 14-CRM(197) and 19F-CRM(197) was specifically labeled by Alexa Fluor 594 hydrazide (red). The CRM(197) was separately labeled red in a reaction that did not label PS. Labeled antigens were incubated with APC which were fixed, permeabilized and incubated with anti-MHC II antibody labeled green by Alexa Fluor 488, followed by confocal microscopy. Labeled CRM(197) was presented on APC surface and co-localized with MHC II (yellow). Labeled unconjugated 14 or 19F PS did not go to the APC surface, but PS labeled 14-CRM(197) and 19F-CRM(197) was internalized and co-localized with MHC II. Monoclonal antibody to type 14 PS bound to intracellular type 14 PS and PS-CRM(197). Brefeldin A and chloroquine blocked both CRM(197) and PS labeled 14-CRM(197) and 19F-CRM(197) from co-localizing with MHC II. These data suggest that the PS component of the CRM(197) glycoconjugate enters the endosome, travels with CRM(197) peptides to the APC surface and co-localizes with MHC II.

  3. π-Conjugated Organometallic Isoindigo Oligomer and Polymer Chromophores: Singlet and Triplet Excited State Dynamics and Application in Polymer Solar Cells.

    Science.gov (United States)

    Goswami, Subhadip; Gish, Melissa K; Wang, Jiliang; Winkel, Russell W; Papanikolas, John M; Schanze, Kirk S

    2015-12-01

    An isoindigo based π-conjugated oligomer and polymer that contain cyclometalated platinum(II) "auxochrome" units were subjected to photophysical characterization, and application of the polymer in bulk heterojunction polymer solar cells with PCBM acceptor was examined. The objective of the study was to explore the effect of the heavy metal centers on the excited state properties, in particular, intersystem crossing to a triplet (exciton) state, and further how this would influence the performance of the organometallic polymer in solar cells. The materials were characterized by electrochemistry, ground state absorption, emission, and picosecond-nanosecond transient absorption spectroscopy. Electrochemical measurements indicate that the cyclometalated units have a significant impact on the HOMO energy level of the chromophores, but little effect on the LUMO, which is consistent with localization of the LUMO on the isoindigo acceptor unit. Picosecond-nanosecond transient absorption spectroscopy reveals a transient with ∼100 ns lifetime that is assigned to a triplet excited state that is produced by intersystem crossing from a singlet state on a time scale of ∼130 ps. This is the first time that a triplet state has been observed for isoindigo π-conjugated chromophores. The performance of the polymer in bulk heterojunction solar cells was explored with PC61BM as an acceptor. The performance of the cells was optimum at a relatively high PCBM loading (1:6, polymer:PCBM), but the overall efficiency was relatively low with power conversion efficiency (PCE) of 0.22%. Atomic force microscopy of blend films reveals that the length scale of the phase separation decreases with increasing PCBM content, suggesting a reason for the increase in PCE with acceptor loading. Energetic considerations show that the triplet state in the polymer is too low in energy to undergo charge separation with PCBM. Further, due to the relatively low LUMO energy of the polymer, charge transfer

  4. The synergistic radiosensitizing effect of tirapazamine-conjugated gold nanoparticles on human hepatoma HepG2 cells under X-ray irradiation

    Directory of Open Access Journals (Sweden)

    Liu X

    2016-07-01

    Full Text Available Xi Liu,1–4 Yan Liu,1–4 Pengcheng Zhang,1–4 Xiaodong Jin,1–3 Xiaogang Zheng,1–4 Fei Ye,1–4 Weiqiang Chen,1–3 Qiang Li1–3 1Institute of Modern Physics, 2Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, 3Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou, 4School of Life Science, University of Chinese Academy of Sciences, Beijing, People’s Republic of China Abstract: Reductive drug-functionalized gold nanoparticles (AuNPs have been proposed to enhance the damage of X-rays to cells through improving hydroxyl radical production by secondary electrons. In this work, polyethylene glycol-capped AuNPs were conjugated with tirapazamine (TPZ moiety, and then thioctyl TPZ (TPZs-modified AuNPs (TPZs-AuNPs were synthesized. The TPZs-AuNPs were characterized by transmission electron microscopy, ultraviolet-visible spectra, dynamic light scattering, and inductively coupled plasma mass spectrometry to have a size of 16.6±2.1 nm in diameter and a TPZs/AuNPs ratio of ~700:1. In contrast with PEGylated AuNPs, the as-synthesized TPZs-AuNPs exhibited 20% increment in hydroxyl radical production in water at 2.0 Gy, and 19% increase in sensitizer enhancement ratio at 10% survival fraction for human hepatoma HepG2 cells under X-ray irradiation. The production of reactive oxygen species in HepG2 cells exposed to X-rays in vitro demonstrated a synergistic radiosensitizing effect of AuNPs and TPZ moiety. Thus, the reductive drug-conjugated TPZs-AuNPs as a kind of AuNP radiosensitizer with low gold loading provide a new strategy for enhancing the efficacy of radiation therapy. Keywords: AuNPs, radiation enhancement, synergistic effect, human hepatoma cells, hydroxyl radical production

  5. The Chemical Basis of Thiol Addition to Nitro-conjugated Linoleic Acid, a Protective Cell-signaling Lipid*♦

    Science.gov (United States)

    Turell, Lucía; Vitturi, Darío A.; Coitiño, E. Laura; Lebrato, Lourdes; Möller, Matías N.; Sagasti, Camila; Salvatore, Sonia R.; Woodcock, Steven R.; Alvarez, Beatriz; Schopfer, Francisco J.

    2017-01-01

    Nitroalkene fatty acids are formed in vivo and exert protective and anti-inflammatory effects via reversible Michael addition to thiol-containing proteins in key signaling pathways. Nitro-conjugated linoleic acid (NO2-CLA) is preferentially formed, constitutes the most abundant nitrated fatty acid in humans, and contains two carbons that could potentially react with thiols, modulating signaling actions and levels. In this work, we examined the reactions of NO2-CLA with low molecular weight thiols (glutathione, cysteine, homocysteine, cysteinylglycine, and β-mercaptoethanol) and human serum albumin. Reactions followed reversible biphasic kinetics, consistent with the presence of two electrophilic centers in NO2-CLA located on the β- and δ-carbons with respect to the nitro group. The differential reactivity was confirmed by computational modeling of the electronic structure. The rates (kon and koff) and equilibrium constants for both reactions were determined for different thiols. LC-UV-Visible and LC-MS analyses showed that the fast reaction corresponds to β-adduct formation (the kinetic product), while the slow reaction corresponds to the formation of the δ-adduct (the thermodynamic product). The pH dependence of the rate constants, the correlation between intrinsic reactivity and thiol pKa, and the absence of deuterium solvent kinetic isotope effects suggested stepwise mechanisms with thiolate attack on NO2-CLA as rate-controlling step. Computational modeling supported the mechanism and revealed additional features of the transition states, anionic intermediates, and final neutral products. Importantly, the detection of cysteine-δ-adducts in human urine provided evidence for the biological relevance of this reaction. Finally, human serum albumin was found to bind NO2-CLA both non-covalently and to form covalent adducts at Cys-34, suggesting potential modes for systemic distribution. These results provide new insights into the chemical basis of NO2-CLA

  6. Trans-10, cis-12 conjugated linoleic acid and the PPAR-γ agonist rosiglitazone attenuate lipopolysaccharide-induced TNF-α production by bovine immune cells.

    Science.gov (United States)

    Perdomo, M C; Santos, J E; Badinga, L

    2011-10-01

    Lipopolysaccharide (LPS) modulates innate immunity through alteration of cytokine production by immune cells. The objective of this study was to examine the effect of exogenous conjugated linoleic acid (CLA) and PPAR-γ agonist, rosiglitazone, on LPS-induced tumor necrosis factor α (TNF-α) production by cultured whole blood from prepubertal Holstein heifers (mean age, 5.5 mo). Compared with unstimulated cells, addition of LPS (10 μg/mL) to the culture medium increased (PTNF-α concentration in cultured whole blood in a dose- and time-dependent manner. The greatest TNF-α stimulation occurred after 12 h of exposure to 1 μg/mL LPS. Coincubation with trans-10, cis-12 CLA isomer (100 μM) or rosiglitazone (10 μM), a PPAR-γ agonist, decreased (PTNF-α production by 13% and 29%, respectively. Linoleic acid and cis-9, trans-11 CLA isomer had no detectable effects on LPS-induced TNF-α production in cultured bovine blood. The PPAR-γ agonist-induced TNF-α attenuation was reversed when blood was treated with both rosiglitazone and GW9662, a selective PPAR-γ antagonist. Addition of rosiglitazone to the culture medium tended to reduce nuclear factor-κ Bp65 concentration in nuclear and cytosolic extracts isolated from cultured peripheral blood mononuclear cells. Results show that LPS is a potent inducer of TNF-α production in bovine blood cells and that trans-10, cis-12 CLA and PPAR-γ agonists may attenuate the pro-inflammatory response induced by LPS in growing dairy heifers. Additional studies are needed to fully characterize the involvement of nuclear factor-κ B in LPS signaling in bovine blood cells.

  7. Galactose conjugated platinum(II) complex targeting the Warburg effect for treatment of non-small cell lung cancer and colon cancer.

    Science.gov (United States)

    Wu, Meng; Li, Hong; Liu, Ran; Gao, Xiangqian; Zhang, Menghua; Liu, Pengxing; Fu, Zheng; Yang, Jinna; Zhang-Negrerie, Daisy; Gao, Qingzhi

    2016-03-03

    Malignant neoplasms exhibit a higher rate of glycolysis than normal cells; this is known as the Warburg effect. To target it, a galactose-conjugated (trans-R,R-cyclohexane-1,2-diamine)-2-chloromalonato-platinum(II) complex (Gal-Pt) was designed, synthesized, and evaluated in five human cancer cell lines and against two different xenograft tumour models. Gal-Pt exhibits much higher aqueous solubility (over 25 times) and improved cytotoxicity than oxaliplatin, especially in human colon (HT29) and lung (H460) cancer cell lines. The safety profile of Gal-Pt was investigated in vivo by exploring the maximum tolerated dose (MTD) and animal mortality rate. The ratios of the animal lethal dosage values to the cytotoxicity in HT29 (LD50/IC50) showed that Gal-Pt was associated with an increased therapeutic index by over 30-fold compared to cisplatin and oxaliplatin. We evaluated in vivo antitumor activity by single agent intravenous treatment comparison studies of Gal-Pt (50 mg/kg as 65% MTD) and cisplatin (3 mg/kg, as 80% MTD) in a H460 lung cancer xenograft model, and with oxaliplatin (7 mg/kg, as 90% MTD) in a HT29 colon cancer xenograft model. The results show that Gal-Pt was more efficacious against H460 than cisplatin, and had superior potency in HT29 cells compared to oxaliplatin under nontoxic dosage conditions. The dependency between cytotoxicity of Gal-Pt and glucose transporters (GLUTs) was investigated by using quercetin as an inhibitor of GLUTs in HT29 cells. The cytotoxic potency of Gal-Pt was highly reduced by the inhibitor, suggesting that the uptake of Gal-Pt was regulated by glucose transporters. The GLUT mediated transportability and cellular uptake of Gal-Pt was also demonstrated using a fluorescent glucose bioprobe in HT29 competition assay.

  8. Enhancement of cellular uptake and cytotoxicity of curcumin-loaded PLGA nanoparticles by conjugation with anti-P-glycoprotein in drug resistance cancer cells

    Institute of Scientific and Technical Information of China (English)

    Wanisa PUNFA; Supachai YODKEEREE; Pornsiri PITCHAKARN; Chadarat AMPASAVATE; Pornngarm LIMTRAKUL

    2012-01-01

    Aim:To compare the anti-cancer activity and cellular uptake of curcumin (Cur) delivered by targeted and non-targeted drug delivery systems in multidrug-resistant cervical cancer cells.Methods:Cur was entrapped into poly (DL-lactide-co-glycolide) (PLGA) nanoparticles (Cur-NPs) in the presence of modified-pluronic F127 stabilizer using nano-precipitation technique.On the surface of Cur-NPs,the carboxy-terminal of modified pluronic F127 was conjugated to the amino-terminal of anti-P-glycoprotein (P-gp) (Cur-NPs-APgp).The physical properties of the Cur-NPs,including particle size,zeta potential,particle morphology and Cur release kinetics,were investigated.Cellular uptake and specificity of the Cur-NPs and Cur-NPs-APgp were detected in cervical cancer cell lines KB-V1 (higher expression of P-gp) and KB-3-1 (lower expression of P-gp) using fluorescence microscope and flow cytometry,respectively.Cytotoxicity of the Cur-NPs and Cur-NPs-APgp was determined using MTT assay.Results:The particle size of Cur-NPs and Cur-NPs-APgp was 127 and 132 nm,respectively.The entrapment efficiency and actual loading of Cur-NPs-APgp (60% and 5μg Cur/mg NP) were lower than those of Cur-NPs (99% and 7 μg Cur/mg NP).The specific binding of Cur-NPs-APgp to KB-V1 cells was significantly higher than that to KB-3-1 cells.Cellular uptake of Cur-NPs-APgp into KB-V1 cells was higher,as compared to KB-3-1 cells.However,the cellular uptake of Cur-NPs and Cur-NPs-lgG did not differ between the two types of cells.Besides,the cytotoxicity of Cur-NPs-APgp in KB-V1 cells was higher than those of Cur and Cur-NPs.Conclusion:The results demonstrate that Cur-NPs-APgp targeted to P-gp on the cell surface membrane of KB-V1 cells,thus enhancing the cellular uptake and cytotoxicity of Cur.

  9. Lysosomal pH Decrease in Inflammatory Cells Used To Enable Activatable Imaging of Inflammation with a Sialic Acid Conjugated Profluorophore.

    Science.gov (United States)

    Yu, Mingzhu; Wu, Xuanjun; Lin, Bijuan; Han, Jiahuai; Yang, Liu; Han, Shoufa

    2015-07-07

    Inflammation causes significant morbidity and mortality, necessitating effective in vivo imaging of inflammation. Prior approaches often rely on combination of optical agents with entities specific for proteinaceous biomarkers overexpressed in inflammatory tissues. We herein report a fundamentally new approach to image inflammation by targeting lysosomes undergoing acidification in inflammatory cells with a sialic acid (Sia) conjugated near-infrared profluorophore (pNIR). Sia-pNIR contains a sialic acid domain for in vivo targeting of inflamed tissues and a pNIR domain which isomerizes into fluorescent and optoacoustic species in acidic lysosomes. Sia-pNIR displays high inflammation-to-healthy tissue signal contrasts in mice treated with Escherichia coli, Staphylococcus aureus, or lipopolysaccharide. In addition, inflammation-associated fluorescence is switched off upon antibiotics treatment in mice. This report shows the potentials of Sia-pNIR for activatable dual-modality inflammation imaging, and particularly the use of lysosomes of inflamed cells as a previously unappreciated biomarker for inflammation imaging.

  10. B-cell epitope of beta toxin of Clostridium perfringens genetically conjugated to a carrier protein: expression, purification and characterization of the chimeric protein.

    Science.gov (United States)

    Bhatia, Bharti; Solanki, Amit Kumar; Kaushik, Himani; Dixit, Aparna; Garg, Lalit C

    2014-10-01

    Beta toxin (btx) is the prime virulence factor for the pathogenesis of Clostridium perfringens type C strain, known to cause necrotic enteritis and enterotoxaemia in mammalian species. The existing vaccines targeting btx are formaldehyde inactivated culture filtrates of Clostridium. These filtrates raise antigenic load in the host leading to nonspecific and poor responses. The present study aimed to overcome these drawbacks and generate a chimeric protein carrying in silico identified B-cell epitope of btx fused with a carrier protein as a vaccine candidate. Using bioinformatic tools, three stretches of amino acids were predicted as putative B-cell epitopes. One of the epitopes spanning 140-156 amino acid residues was genetically conjugated with B-subunit of heat labile enterotoxin (LTB) of Escherichia coli and expressed as a translational fusion in Vibrio cholerae secretory expression system. High level expression of the recombinant fusion protein rLTB-Btx140-156 was obtained and the protein was successfully purified. The recombinant protein retained the native LTB property to pentamerize and bind to GM1 ganglioside receptor of LTB. The antigenicity of both the epitope and the carrier protein was maintained in fusion protein as indicated by immunoblotting against anti-LTB and anti-btx antibody. The rLTB-Btx140-156 fusion protein therefore can be evaluated as a potential vaccine candidate against C. perfringens.

  11. Temozolomide-perillyl alcohol conjugate induced reactive oxygen species accumulation contributes to its cytotoxicity against non-small cell lung cancer

    Science.gov (United States)

    Song, Xingguo; Xie, Li; Wang, Xingwu; Zeng, Qian; Chen, Thomas C.; Wang, Weijun; Song, Xianrang

    2016-01-01

    Temozolomide-perillyl alcohol conjugate (TMZ − POH), a novel temozolomide analog, was reported to play a cytotoxic role in triple-negative breast cancer and TMZ-resistant gliomas. In a current study we had demonstrated how TMZ − POH also exhibited its cytotoxicity against non-small cell lung cancer (NSCLC), the most common type of lung cancer, as evidence from cell/tumor proliferation inhibition, G2/M arrest, DNA damage and mitochondrial apoptosis. Importantly, TMZ − POH’s cytotoxicity is closely related to reactive oxygen species (ROS) accumulation because it can be reversed by two ROS scavengers, catalase (CAT) and N-acetyl-L-cysteine (NAC). TMZ − POH induces mitochondrial transmembrane potential (MTP) decrease and ROS accumulation, in turn activates mitogen-activated protein kinase (MAPKs) signaling and mitochondrial apoptosis, and then exerts its cytotoxicity, thus proposing TMZ − POH as a potential therapeutic candidate for NSCLC. PMID:26949038

  12. Conjugated Bilirubin Differentially Regulates CD4+ T Effector Cells and T Regulatory Cell Function through Outside-In and Inside-Out Mechanisms: The Effects of HAV Cell Surface Receptor and Intracellular Signaling

    Science.gov (United States)

    Corral-Jara, Karla F.; Gómez-Leyva, Juan F.; Rosenstein, Yvonne; Jose-Abrego, Alexis; Roman, Sonia

    2016-01-01

    We recently reported an immune-modulatory role of conjugated bilirubin (CB) in hepatitis A virus (HAV) infection. During this infection the immune response relies on CD4+ T lymphocytes (TLs) and it may be affected by the interaction of HAV with its cellular receptor (HAVCR1/TIM-1) on T cell surface. How CB might affect T cell function during HAV infection remains to be elucidated. Herein, in vitro stimulation of CD4+ TLs from healthy donors with CB resulted in a decrease in the degree of intracellular tyrosine phosphorylation and an increase in the activity of T regulatory cells (Tregs) expressing HAVCR1/TIM-1. A comparison between CD4+ TLs from healthy donors and HAV-infected patients revealed changes in the TCR signaling pathway relative to changes in CB levels. The proportion of CD4+CD25+ TLs increased in patients with low CB serum levels and an increase in the percentage of Tregs expressing HAVCR1/TIM-1 was found in HAV-infected patients relative to controls. A low frequency of 157insMTTTVP insertion in the viral receptor gene HAVCR1/TIM-1 was found in patients and controls. Our data revealed that, during HAV infection, CB differentially regulates CD4+ TLs and Tregs functions by modulating intracellular pathways and by inducing changes in the proportion of Tregs expressing HAVCR1/TIM-1. PMID:27578921

  13. Conjugated Polymers for Energy Production

    DEFF Research Database (Denmark)

    Livi, Francesco

    arylation (DAr) and direct arylation polymerization (DArP) have been applied to the preparation of PPDTBT, making this polymer readily available in only 4 synthetic steps and thus easily transferable to a large scale-production setup. DArP avoids organometallic species and therefore is an appealing......This dissertation is aimed at developing materials for flexible, large area, ITO-free polymer solar cells (PSCs) fully printed under ambient conditions. A large screening of conjugated polymers, both novel and well-known materials, has been carried out in order to find suitable candidates...... for scalable PSCs fully printed under ambient conditions [Adv. Energy Mater. 2015, 5, 1402186]. PPDTBT resulted to be the conjugated polymer with the best photovoltaic performance within the 104 synthesized macromolecules. Therefore, further studies have been done on such material. The impact of side chain...

  14. Deciphering conjugative plasmid permissiveness in wastewater microbiomes

    DEFF Research Database (Denmark)

    Jacquiod, Samuel Jehan Auguste; Brejnrod, Asker Daniel; Milani, Stefan Morberg

    2017-01-01

    Wastewater treatment plants (WWTPs) are designed to robustly treat polluted water. They are characterized by ceaseless flows of organic, chemical and microbial matter, followed by treatment steps before environmental release. WWTPs are hotspots of horizontal gene transfer between bacteria via...... still remains largely uncharted. Furthermore, current in vitro methods used to assess conjugation in complex microbiomes do not include in situ behaviours of recipient cells, resulting in partial understanding of transfers. We investigated the in vitro conjugation capacities of WWTP microbiomes from...... diversity of recipient bacterial phyla for the plasmid was observed, especially in WWTP outlets. We also identified permissive bacteria potentially able to cross WWTPs and engage in conjugation before and after water treatment. Bacterial activity and lifestyle seem to influence conjugation extent...

  15. The Chemistry and Biology of Oligonucleotide Conjugates

    Science.gov (United States)

    Juliano, R.L.; Ming, Xin; Nakagawa, Osamu

    2012-01-01

    CONSPECTUS Short DNA or RNA oligonucleotides have tremendous potential as therapeutic agents. Because of their ability to engage in Watson-Crick base pairing they can interact with messenger mRNA or pre-mRNA targets with high selectivity and thus offer the possibility of precise manipulation of gene expression. This possibility has engendered extensive efforts to develop oligonucleotides as drugs, with many candidates already in clinical trials. However, a major impediment to the maturation of oligonucleotide-based therapeutics is the fact that these relatively large and usually highly charged molecules have great difficulty crossing cellular membranes and thus in penetrating to their sites of action in the cytosol or nucleus. In this Account we first summarize some basic aspects of the biology of antisense and siRNA oligonucleotides and then discuss chemical conjugation as an approach to improving the intracellular delivery and therapeutic potential of these agents. Our emphasis will be on the pharmacological ramifications of oligonucleotide conjugates rather than the details of conjugation chemistry. One important approach has been conjugation with ligands designed to bind to particular receptors and thus provide specificity to the interaction of cells with oligonucleotides. Another approach has been to couple antisense or siRNA with agents such as cell penetrating peptides that are designed to provoke escape of the conjugate from intracellular vesicular compartments. Both of these approaches have enjoyed some success. However, there remains much to be learned before oligonucleotide conjugates can find an important place in human therapeutics. PMID:22353142

  16. RGD-conjugated rod-like viral nanoparticles on 2D scaffold improved bone differentiation of mesenchymal stem cells

    Science.gov (United States)

    Wang, Qian; Pongkwan, Sitasuwan; Lee, L.; Li, Kai; Nguyen, Huong

    2014-05-01

    Viral nanoparticles have uniform and well-defined nano-structures and can be produced in large quantities. Several plant viral nanoparticles have been tested in biomedical applications due to the lack of mammalian cell infectivity. We are particularly interested in using Tobacco mosaic virus (TMV), which has been demonstrated to enhance bone tissue regeneration, as a tuneable nanoscale building block for biomaterials development. Unmodified TMV particles have been shown to accelerate osteogenic differentiation of adult stem cells by synergistically upregulating BMP2 and IBSP expression with dexamethasone. However, the lack of affinity to mammalian cell surface resulted in low initial cell adhesion. In this study, to increase cell binding capacity of TMV based material the chemical functionalization of TMV with arginine-glycine-aspartic acid (RGD) peptide was explored. An azide-derivatized RGD peptide was “clicked” to tyrosine residues on TMV outer surface via an efficient copper(I) catalysed azide-alkyne cycloaddition reaction. The ligand spacing is calculated to be 2-4 nm, which could offer a polyvalent ligand clustering effect for enhanced cell receptor signalling, further promoting the proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells.

  17. RGD-conjugated rod-like viral nanoparticles on 2D scaffold improved bone differentiation of mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Qian eWang

    2014-05-01

    Full Text Available Viral nanoparticles have uniform and well-defined nano-structures and can be produced in large quantities. Several plant viral nanoparticles have been tested in biomedical applications due to the lack of mammalian cell infectivity. We are particularly interested in using Tobacco mosaic virus (TMV, which has been demonstrated to enhance bone tissue regeneration, as a tuneable nanoscale building block for biomaterials development. Unmodified TMV particles have been shown to accelerate osteogenic differentiation of adult stem cells by synergistically upregulating BMP2 and IBSP expression with dexamethasone. However, the lack of affinity to mammalian cell surface resulted in low initial cell adhesion. In this study, to increase cell binding capacity of TMV based material the chemical functionalization of TMV with arginine-glycine-aspartic acid (RGD peptide was explored. An azide-derivatized RGD peptide was clicked to tyrosine residues on TMV outer surface via an efficient copper(I catalysed azide-alkyne cycloaddition reaction. The ligand spacing is calculated to be 2-4 nm, which could offer a polyvalent ligand clustering effect for enhanced cell receptor signalling, further promoting the proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells.

  18. RGD-conjugated rod-like viral nanoparticles on 2D scaffold improve bone differentiation of mesenchymal stem cells

    Science.gov (United States)

    Sitasuwan, Pongkwan; Lee, L. Andrew; Li, Kai; Nguyen, Huong Giang; Wang, Qian

    2014-01-01

    Viral nanoparticles have uniform and well-defined nano-structures and can be produced in large quantities. Several plant viral nanoparticles have been tested in biomedical applications due to the lack of mammalian cell infectivity. We are particularly interested in using Tobacco mosaic virus (TMV), which has been demonstrated to enhance bone tissue regeneration, as a tunable nanoscale building block for biomaterials development. Unmodified TMV particles have been shown to accelerate osteogenic differentiation of adult stem cells by synergistically upregulating bone morphogenetic protein 2 (BMP2) and integrin-binding bone sialoprotein (IBSP) expression with dexamethasone. However, their lack of affinity to mammalian cell surface resulted in low initial cell adhesion. In this study, to increase cell binding capacity of TMV based material the chemical functionalization of TMV with arginine-glycine-aspartic acid (RGD) peptide was explored. An azide-derivatized RGD peptide was “clicked” to tyrosine residues on TMV outer surface via an efficient copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The ligand spacing is calculated to be 2–4 nm, which could offer a polyvalent ligand clustering effect for enhanced cell receptor signaling, further promoting the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). PMID:24904922

  19. Radiosensitizing and Hyperthermic Properties of Hyaluronan Conjugated, Dextran-Coated Ferric Oxide Nanoparticles: Implications for Cancer Stem Cell Therapy

    Directory of Open Access Journals (Sweden)

    Ranjeeta Thapa

    2015-01-01

    Full Text Available Cytotoxicity, radiosensitivity, and hyperthermia sensitivity of hyaluronan-mediated dextran-coated super paramagnetic iron oxide nanoparticles (HA-DESPIONs were assessed in CD44-expressing head and neck squamous cell carcinoma (HNSCC cell lines at clinically relevant radiation dose and temperatures. Low-passage HNSCC cells were exposed to HA-DESPIONs and cytotoxicity was assessed using MTT assay. Radiosensitizing properties of graded doses of HA-DESPIONs were assessed in both unsorted and CD44-sorted cells using clonogenic assay in combination with 2 Gy exposure to X-rays. Hyperthermia-induced toxicity was measured at 40°C, 41°C, and 42°C using clonogenic assay. Cell death was assessed 24 hours after treatment using a flow cytometry-based apoptosis analysis. Results showed that HA-DESPIONs were nontoxic at moderate concentrations and did not directly radiosensitize the cell lines. Further, there was no significant difference in the radiosensitivity of CD44high and CD44low cells. However, HA-DESPIONs enhanced the effect of hyperthermia which resulted in reduced cell survival that appeared to be mediated through apoptosis. We demonstrated that HA-DESPIONs are nontoxic and although they do not enhance radiation sensitivity, they did increase the effect of local hyperthermia. These results support further development of drug-attached HA-DESPIONs in combination with radiation for targeting cancer stem cells (CSCs and the development of an alternating magnetic field approach to activate the HA-DESPIONs attached to CSCs.

  20. t10c12 conjugated linoleic acid suppresses HER2 protein and enhances apoptosis in SKBr3 breast cancer cells: possible role of COX2.

    Directory of Open Access Journals (Sweden)

    Margaret Flowers

    Full Text Available BACKGROUND: HER2-targeted therapy with the monoclonal antibody trastuzumab (Herceptin has improved disease-free survival for women diagnosed with HER2-positive breast cancers; however, treatment resistance and disease progression are not uncommon. Current data suggest that resistance to treatment in HER2 cancers may be a consequence of NF-kappaB overexpression and increased COX2-derived prostaglandin E2 (PGE(2. Conjugated linoleic acid (CLA has been shown to have anti-tumor properties and to inhibit NF-kappaB activity and COX2. METHODS: In this study, HER2-overexpressing SKBr3 breast cancer cells were treated with t10c12 CLA. Protein expression of the HER2 receptor, nuclear NF-kappaB p65, and total and phosphorylated IkappaB were examined by western blot and immunofluorescence. PGE(2 levels were determined by ELISA. Proliferation was measured by metabolism of 3-(4, 5-Dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT, and apoptosis was measured by FITC-conjugated Annexin V staining and flow cytometry. RESULTS/CONCLUSIONS: We observed a significant decrease in HER2 protein expression on western blot following treatment with 40 and 80 microM t10c12 CLA (p<0.01 and 0.001, respectively and loss of HER2 protein in cells using immunoflourescence that was most pronounced at 80 microM. Protein levels of nuclear NF-kappaB p65 were also significantly reduced at the 80 microM dose. This was accompanied by a significant decrease in PGE(2 levels (p = 0.05. Pretreatment with t10c12 CLA significantly enhanced TNFalpha-induced apoptosis and the anti-proliferative action of trastuzumab (p = 0.05 and 0.001, respectively. These data add to previous reports of an anti-tumor effect of t10c12 CLA and suggest an effect on the HER2 oncogene that may be through CLA mediated downregulation of COX2-derived PGE(2.

  1. Carrier priming effect of CRM197 is related to an enhanced B and T cell activation in meningococcal serogroup A conjugate vaccination. Immunological comparison between CRM197 and diphtheria toxoid.

    Science.gov (United States)

    Pecetta, S; Tontini, M; Faenzi, E; Cioncada, R; Proietti, D; Seubert, A; Nuti, S; Berti, F; Romano, M R

    2016-04-29

    Glycoconjugate vaccines are composed of capsular polysaccharides (CPSs) of a pathogenic bacteria covalently linked to carrier proteins. Pre-exposure to the carrier is known to influence the efficacy of the glycoconjugate, by inducing enhanced or suppressed anti-CPS response. Following our previous work on the immunogenicity of diphtheria toxin mutant CRM197 and formaldehyde-treated diphtheria toxoid (DT) as carriers for meningococcal A (MenA) conjugates in mouse model, we further investigated the role of the carrier on the immunological response to glycoconjugate vaccines. We previously showed that high dosage DT priming could result in carrier-induced epitopic suppression (CIES), an event that did not occur for CRM197 priming, and we observed that anti-DT IgGs could cross-react with DT based conjugates in vitro. Here, we confirmed the cross-reactivity of anti-carrier IgGs with DT conjugates in vivo. Furthermore, we analyzed the splenocytes of animals primed with the carrier and subsequently immunized with the MenA conjugate. Pre-exposure to the carrier protein, both CRM197 and DT, resulted in increased carrier-specific plasma and memory B cell response. However, only for CRM197 priming an enhanced carbohydrate-specific plasma cell response was observed. Analysis of circulating IgGs confirmed these observations. Memory to the CPS resulted to be non-influenced by carrier priming. Analysis of T helper response showed an enhancement effect for CRM197 priming, while DT priming resulted in constrained T cell activation. Stimulation with CRM197, which does not require formaldehyde detoxification, of splenocytes from animal immunized with DT suggested that the formaldehyde treatment used to produce DT might be the cause of limited presentation of the antigen to the T cells. We concluded that the dominant carrier-specific B cell response in case of limited T cell recruitment might explain the previously observed CIES phenomenon in case of DT priming.

  2. Effect of a weak electric field on the distribution of con-A positive glyco-conjugates on the cell surface of normal limb bud cells in tissue culture

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, K.

    1988-01-01

    The purpose of this study was to investigate the role of cell- surface glyco-conjugates (CS-GC) when cells are exposed to a weak electromagnetic field (EMF). Primary cell cultures of limb bud from 6 day old chick embryos were established on thermanox and then exposed to a 1000 mv/mm EMF. It was observed that cells oriented their long axis perpendicular to the EMF and migrated to the cathode. It was hypothesized that a CS-GC us electrophoresed to the cathode-facing cell-surface and causes the changes in cell behavior. To test this hypothesis concanavalin-A labelled with fluorescence isothiocyanate was used to detect CS-GC. Epifluorescence studies show a localization CS-GC on the cathode- facing cell- surface after two hours, that the degree of this localization is dependent upon field strength; and that it is reversible in living limb bud cells. The authors conclude that CS-GC's are localized at the cathode face and may play a role in observed cellular behavior when cells are exposed to an EMF.

  3. Aesthetically Pleasing Conjugated Polymer: Fullerene Blends for Blue-Green Solar Cells Via Roll-to-Roll Processing

    DEFF Research Database (Denmark)

    Amb, Chad M.; Craig, Michael R.; Koldemir, Unsal

    2012-01-01

    as a thin-film deposition technique due its convenience. We report on the significant differences between the spin-coating of laboratory solar cells and slot-die coating of a blue-green colored, low bandgap polymer (PGREEN). This is one of the first demonstrations of slot-die-coated polymer solar cells OPVs...... not utilizing poly(3-hexylthiophene):(6,6)-phenyl-C61-butyric acid methyl ester (PCBM) blends as a light absorbing layer. Through synthetic optimization, we show that strict protocols are necessary to yield polymers which achieve consistent photovoltaic behavior. We fabricated spin-coated laboratory scale OPV......The practical application of organic photovoltaic (OPV) cells requires high throughput printing techniques in order to attain cells with an area large enough to provide useful amounts of power. However, in the laboratory screening of new materials for OPVs, spin-coating is used almost exclusively...

  4. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    G Padmanaban; S Ramakrishnan

    2003-08-01

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying excitation energies. The latter feature, especially when the chromophores are fluorescent, like in MEHPPV, makes these systems particularly interesting from the photophysics point of view. Segmented MEHPPV- samples, where x represents the mole fraction of conjugated segments, were prepared by a novel approach that utilizes a suitable precursor wherein selective elimination of one of the two eliminatable groups is affected; the uneliminated units serve as conjugation truncations. Control of the composition x of the precursor therefore permits one to prepare segmented MEHPPV- samples with varying levels of conjugation (elimination). Using fluorescence spectroscopy, we have seen that even in single isolated polymer chains, energy migration from the shorter (higher energy) chromophores to longer (lower energy) ones occurs – the extent of which depends on the level of conjugation. Further, by varying the solvent composition, it is seen that the extent of energy transfer and the formation of poorly emissive inter-chromophore excitons are greatly enhanced with increasing amounts of non-solvent. A typical S-shaped curve represents the variation of emission yields as a function of composition suggestive of a cooperative collapse of the polymer coil, reminiscent of conformational transitions seen in biological macromolecules.

  5. Aesthetically pleasing conjugated polymer:fullerene blends for blue-green solar cells via roll-to-roll processing.

    Science.gov (United States)

    Amb, Chad M; Craig, Michael R; Koldemir, Unsal; Subbiah, Jegadesan; Choudhury, Kaushik Roy; Gevorgyan, Suren A; Jørgensen, Mikkel; Krebs, Frederik C; So, Franky; Reynolds, John R

    2012-03-01

    The practical application of organic photovoltaic (OPV) cells requires high throughput printing techniques in order to attain cells with an area large enough to provide useful amounts of power. However, in the laboratory screening of new materials for OPVs, spin-coating is used almost exclusively as a thin-film deposition technique due its convenience. We report on the significant differences between the spin-coating of laboratory solar cells and slot-die coating of a blue-green colored, low bandgap polymer (PGREEN). This is one of the first demonstrations of slot-die-coated polymer solar cells OPVs not utilizing poly(3-hexylthiophene):(6,6)-phenyl-C(61)-butyric acid methyl ester (PCBM) blends as a light absorbing layer. Through synthetic optimization, we show that strict protocols are necessary to yield polymers which achieve consistent photovoltaic behavior. We fabricated spin-coated laboratory scale OPV devices with PGREEN: PCBM blends as active light absorbing layers, and compare performance to slot die-coated individual solar cells, and slot-die-coated solar modules consisting of many cells connected in series. We find that the optimum ratio of polymer to PCBM varies significantly when changing from spin-coating of thinner active layer films to slot-die coating, which requires somewhat thicker films. We also demonstrate the detrimental impacts on power conversion efficiency of high series resistance imparted by large electrodes, illustrating the need for higher conductivity contacts, transparent electrodes, and high mobility active layer materials for large-area solar cell modules.

  6. Platinum (IV)-fatty acid conjugates overcome inherently and acquired Cisplatin resistant cancer cell lines: an in-vitro study.

    Science.gov (United States)

    Ratzon, Einav; Najajreh, Yousef; Salem, Rami; Khamaisie, Hazem; Ruthardt, Martin; Mahajna, Jamal

    2016-02-23

    Platinum-based drugs are used as cancer chemotherapeutics for the last 40 years. However, drug resistance and nephrotoxicity are the major limitations of the use of platinum-based compounds in cancer therapy. Platinum (IV) complexes are believed to act as platinum prodrugs and are able to overcome some of platinum (II) limitations. A number of previously sensitized platinum (IV) complexes were evaluated for their anti-cancer activity by monitoring ability to affect proliferation, clonigenicity and apoptosis induction of Cisplatin sensitive and resistant cancer cells. In addition, the uptake of Cisplatin and the platinum (IV) derivatives to Cisplatin sensitive and resistant cancer cells was monitored. The bis-octanoatoplatinum (IV) complex (RJY13), a Cisplatin derivative with octanoate as axial ligand, exhibited strong anti-proliferative effect on the Cisplatin resistant and sensitive ovarian cells, A2780cisR and A2780, respectively. Moreover, RJY13 exhibited good activity in inhibiting clonigenicity of both cells. Anti-proliferative activity of RJY13 was mediated by induction of apoptosis. Interestingly, a bis-lauratopaltinum (IV) complex (RJY6) was highly potent in inhibiting clonigenicity of both Cisplatin sensitive and Cisplatin resistant cells, however, exhibited reduced activity in assays that utilize cells growing in two dimensional (2D) conditions. The uptake of Cisplatin was reduced by 30% in A2780 in which the copper transporter-1 (Ctr1) was silenced. Moreover, uptake of RJY6 was marginally dependent on Ctr1, while uptake of RJY13 was Ctr1-independent. Our data demonstrated the potential of platinum (IV) prodrugs in overcoming acquired and inherited drug resistance in cancer cell lines. Moreover, our data demonstrated that the uptake of Cisplatin is partially dependent on Ctr1 transporter, while uptake of RJY6 is marginally dependent on Ctr1 and RJY13 is Ctr1-independent. In addition, our data illustrated the therapeutic potential of platinum (IV) prodrugs

  7. Conjugated linoleic acids (CLAs) decrease prostate cancer cell proliferation: different molecular mechanisms for cis-9, trans-11 and trans-10, cis-12 isomers.

    Science.gov (United States)

    Ochoa, Julio J; Farquharson, Andrew J; Grant, Ian; Moffat, L E; Heys, Steven D; Wahle, Klaus W J

    2004-07-01

    The aims of this study were to examine the anti-proliferative effects of different concentrations of a commercial preparation of conjugated linoleic acids (CLA) mixture of isomers [cis-9, trans-11 CLA (c9,t11 CLA): trans-10, cis-12 CLA (50:50)] and their constituent isomers on PC-3, a human prostatic carcinoma cell line, and to study their effects on gene expression (mRNA and protein levels) of different enzymes and oncoproteins involved in oncogenesis and progression of prostate cancer. This includes pathways for arachidonic acid metabolism [cyclooxygenase 1 (COX-1), 2 (COX-2) and 5-lipoxygenase (5-LOX)], apoptosis (bcl-2) and cell cycle control (p21(WAF/Cip1)). Our results indicate a significant decrease in PC-3 proliferation elicited by CLA, although with high variability between isomers. The trans-10, cis-12 CLA was the most effective isomer (55% inhibition). This isomer was also able to decrease bcl-2 gene expression and to increase p21(WAF1/Cip1) mRNA levels (60% increase at highest concentration). In contrast, cis-9, trans-11 had no effect on these proteins but had a clear effect on 5-LOX expression and to a lesser degree on COX-2 protein level isomers. In conclusion, the anti-proliferative effects on PC-3 of CLA mixture and their constituent isomers are not equivalent, due to the different pathways involved for individual isomers. Trans-10, cis-12 seems to work preferentially through modulation of apoptosis and cell cycle control, while c9,t11 CLA isomer affects arachidonic acid metabolism.

  8. On the dynamics of StemBells: Microbubble-conjugated stem cells for ultrasound-controlled delivery

    Science.gov (United States)

    Kokhuis, Tom J. A.; Naaijkens, Benno A.; Juffermans, Lynda J. M.; Kamp, Otto; van der Steen, Antonius F. W.; Versluis, Michel; de Jong, Nico

    2017-07-01

    The use of stem cells for regenerative tissue repair is promising but hampered by the low number of cells delivered to the site of injury. To increase the delivery, we propose a technique in which stem cells are linked to functionalized microbubbles, creating echogenic complex dubbed StemBells. StemBells are highly susceptible to acoustic radiation force which can be employed after injection to push the StemBells locally to the treatment site. To optimally benefit from the delivery technique, a thorough characterization of the dynamics of StemBells during ultrasound exposure is needed. Using high-speed optical imaging, we study the dynamics of StemBells as a function of the applied frequency from which resonance curves were constructed. A theoretical model, based on a modified Rayleigh-Plesset type equation, captured the experimental resonance characteristics and radial dynamics in detail.

  9. Using cyclopenta[2,1-b:3,4-c']dithiophene-4-one as a building block for low-bandgap conjugated copolymers applied in solar cells.

    Science.gov (United States)

    Zhang, Wei; Cao, Jiamin; Liu, Ying; Xiao, Zuo; Zhu, Weiguo; Zuo, Qiqun; Ding, Liming

    2012-09-26

    A novel electron-accepting unit cyclopenta[2,1-b:3,4-c']dithiophene-4-one (CPDTO-c'), which is an isomer of CPDTO-b' was developed. CPDTO-c' can be incorporated into the D-A backbone through 5, 7 positions. The 2 position of CPDTO-c' can be easily functionalized with an electron-withdrawing chain. By copolymerizing CPDTO-c' with four different donor units: benzo[1,2-b:4,5-b']dithiophene (BDT), dithieno[3,2-b:2',3'-d]silole (DTS), carbazole, and fluorene, four new conjugated copolymers P1-P4 were obtained. All these polymers have good solubility and low-lying HOMO energy levels (-5.41 ∼ -5.92 eV). Among them, P1 and P2 exhibit broad absorption and narrow optical bandgaps of 1.91 and 1.72 eV, respectively. Solar cells based on P1/PC(71) BM afforded a PCE up to 2.72% and a high V(oc) up to ∼0.9 V.

  10. Characterization of Asia 1 sdAb from camels bactrianus (C. bactrianus and conjugation with quantum dots for imaging FMDV in BHK-21 cells.

    Directory of Open Access Journals (Sweden)

    Shuanghui Yin

    Full Text Available Foot-and-mouth disease (FMD, caused by FMD virus (FMDV, is a highly contagious viral disease affecting cloven-hoofed animals. Camelids have a unique immunoglobulin profile, with the smallest functional heavy-chain antibodies (sdAb or VHH naturally devoid of light chains with antigen-binding capacity. We screened and characterized five sdAbs against FMDV by immunized library from C. bactrianus with Asia 1 virus-like particles (VLPs. Three of five recombinant sdAbs were stably expressed in E.coli, remained highly soluble, and were serotype-specific for VP1 protein of FMDV Asia 1 by ELISA. These failed to completely neutralize the Asia 1 virus. According to the KD value of binding affinity to three sdAbs, which ranged from 0.44 to 0.71 nm by SPR, sdAb-C6 was selected and conjugated with Zn/CdSe quantum dots (QDs to form a QDs-C6 probe, which was used to trace and image the subcellular location of FMDV in BHK-21 cells. The results show that FMD virions were observed from 3 h.p.i., and most of virions were distributed on one side of the nucleus in the cytoplasm. We demonstrate the utility of sdAbs as functionalized QDs are powerful tools for FMDV research.

  11. 6H-Indolo[2,3-b]quinoxaline-based organic dyes containing different electron-rich conjugated linkers for highly efficient dye-sensitized solar cells

    Science.gov (United States)

    Qian, Xing; Gao, Huan-Huan; Zhu, Yi-Zhou; Lu, Lin; Zheng, Jian-Yu

    2015-04-01

    A new class of organic dyes based on 6H-indolo[2,3-b]quinoxaline are synthesized and applied as photosensitizers for dye-sensitized solar cells. Different electron-rich π-conjugated bridges such as oligothiophene, thienyl carbazole, and furyl carbazole are introduced to cooperate with 6H-indolo[2,3-b]quinoxaline and cyanoacrylic acid anchoring group to give the dyes JY01, JY02, and JY03, respectively. Their photophysical, electrochemical, and photovoltaic properties are further investigated. All three dyes show good performances as photosensitizers. In particular, DSSC based on JY01 shows the best photovoltaic performance with a short-circuit photocurrent density of 16.0 mA cm-2, an open-circuit photovoltage of 708 mV and a fill factor of 0.67, corresponding to an overall power conversion efficiency of 7.62% under AM 1.5 irradiation (100 mW cm-2).

  12. Highly Efficient p-i-n Perovskite Solar Cells Utilizing Novel Low-Temperature Solution-Processed Hole Transport Materials with Linear π-Conjugated Structure.

    Science.gov (United States)

    Li, Yang; Xu, Zheng; Zhao, Suling; Qiao, Bo; Huang, Di; Zhao, Ling; Zhao, Jiao; Wang, Peng; Zhu, Youqin; Li, Xianggao; Liu, Xicheng; Xu, Xurong

    2016-09-01

    Alternative low-temperature solution-processed hole-transporting materials (HTMs) without dopant are critical for highly efficient perovskite solar cells (PSCs). Here, two novel small molecule HTMs with linear π-conjugated structure, 4,4'-bis(4-(di-p-toyl)aminostyryl)biphenyl (TPASBP) and 1,4'-bis(4-(di-p-toyl)aminostyryl)benzene (TPASB), are applied as hole-transporting layer (HTL) by low-temperature (sub-100 °C) solution-processed method in p-i-n PSCs. Compared with standard poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT:PSS) HTL, both TPASBP and TPASB HTLs can promote the growth of perovskite (CH3 NH3 PbI3 ) film consisting of large grains and less grain boundaries. Furthermore, the hole extraction at HTL/CH3 NH3 PbI3 interface and the hole transport in HTL are also more efficient under the conditions of using TPASBP or TPASB as HTL. Hence, the photovoltaic performance of the PSCs is dramatically enhanced, leading to the high efficiencies of 17.4% and 17.6% for the PSCs using TPASBP and TPASB as HTL, respectively, which are ≈40% higher than that of the standard PSC using PEDOT:PSS HTL.

  13. Water-Soluble 8-Hydroxyquinoline Conjugate of Amino-Glucose As Receptor for La(3+) in HEPES Buffer, on Whatman Cellulose Paper and in Living Cells.

    Science.gov (United States)

    Areti, Sivaiah; Bandaru, Sateesh; Teotia, Rohit; Rao, Chebrolu P

    2015-12-15

    A water-soluble glucopyranosyl conjugate, L, has been synthesized and characterized by different analytical and spectral techniques. The L has been demonstrated to have switch-on fluorescence enhancement of ∼75 fold in the presence of La(3+) among the nine lanthanide ions studied in the HEPES buffer at pH 7.4. A minimum detection limit of 140 nM (16 ± 2 ppb) was shown by L for La(3+) in the buffer at physiological pH. The utility of L has been demonstrated by showing its sensitivity toward La(3+) on Whatman filter paper strips. The reversible and reusable action of L has been demonstrated by monitoring the fluorescence changes as a function of the addition of La(3+) followed by F(-) and HPO4(2-) ions. The complexation of L by La(3+) was shown by absorption spectra wherein isosbestic behavior was observed. The Job's plot suggests a 2:1 complex between L and La(3+), and the same was supported by ESI-MS. The control molecular study revealed the necessity of hydroxy quinoline and the amine group for La(3+) ion binding and the glyco-moiety to bring water solubility and biocompatibility. The structural features of the [2L+La(3+)] complex were established by DFT computational calculations. The chemo-ensemble, [2L+La(3+)], is shown responsible for providing intracellular fluorescence imaging in HepG2 cells.

  14. Bis(thienothiophenyl) diketopyrrolopyrrole-based conjugated polymers with various branched alkyl side chains and their applications in thin-film transistors and polymer solar cells.

    Science.gov (United States)

    Shin, Jicheol; Park, Gi Eun; Lee, Dae Hee; Um, Hyun Ah; Lee, Tae Wan; Cho, Min Ju; Choi, Dong Hoon

    2015-02-11

    New thienothiophene-flanked diketopyrrolopyrrole and thiophene-containing π-extended conjugated polymers with various branched alkyl side-chains were successfully synthesized. 2-Octyldodecyl, 2-decyltetradecyl, 2-tetradecylhexadecyl, 2-hexadecyloctadecyl, and 2-octadecyldocosyl groups were selected as the side-chain moieties and were anchored to the N-positions of the thienothiophene-flanked diketopyrrolopyrrole unit. All five polymers were found to be soluble owing to the bulkiness of the side chains. The thin-film transistor based on the 2-tetradecylhexadecyl-substituted polymer showed the highest hole mobility of 1.92 cm2 V(-1) s(-1) due to it having the smallest π-π stacking distance between the polymer chains, which was determined by grazing incidence X-ray diffraction. Bulk heterojunction polymer solar cells incorporating [6,6]-phenyl-C71-butyric acid methyl ester as the n-type molecule and the additive 1,8-diiodooctane (1 vol %) were also constructed from the synthesized polymers without thermal annealing; the device containing the 2-octyldodecyl-substituted polymer exhibited the highest power conversion efficiency of 5.8%. Although all the polymers showed similar physical properties, their device performance was clearly influenced by the sizes of the branched alkyl side-chain groups.

  15. Novel pH-sensitive charge-reversal cell penetrating peptide conjugated PEG-PLA micelles for docetaxel delivery: in vitro study.

    Science.gov (United States)

    Ouahab, Ammar; Cheraga, Nihad; Onoja, Vitus; Shen, Yan; Tu, Jiasheng

    2014-05-15

    In order to create a pH-sensitive charge-reversal system for cell penetrating peptides (CPP) to prevent non-specific internalization of the drug; and concomitantly enhance the physical stability and tumor targetability of poly(ethylene glycol)-poly(d,l-lactide) (PEG-PLA) micelles, two sets of novel PEG-PLA micelles were developed. Cell penetrating decapeptide arginine-glycine (RG)5 and a pH-sensitive masking decapeptide histidine-glutamic acid (HE)5 were conjugated at the PEG free end to produce pH sensitive with peptides outside micelles (PHPO), while the pH sensitive with peptides inside micelles (PHPI) are the micelles obtained with the two peptides conjugated to the free end of the PLA block. The polymers were successfully synthesized and characterized by (1)H NMR and GPC. The mixed micelles were prepared and characterized for their loading efficiency, particle size and zeta potential. The surface charge of PHPO was greatly affected by the pH of the solution and (RG)5:(HE)5 ratio at the surface. The pH value of the solution at which the surface charge of PHPO reversed could be manipulated by the feed ratio of (RG)5-PEG-PLA (RGO) and (HE)5-PEG-PLA (HEO), hence, HEO:RGO molar ratio of 45:55 was selected for tumor targeting. Docetaxel (DTX) was sufficiently solubilized by DTX-PHPO with a loading efficiency of 90.18 ± 1.65%. At pH 7.4, DTX loaded mPEG-PLA (DTX-PM) (41.2 ± 0.3 nm), DTX-PHPO (195.3 ± 1.9 nm) and DTX-PHPI (190.9 ± 4.5 nm) showed sustained DTX release of less than 55% within 48 h. However, at pH 6.8 DTX-PHPI released 87.29 ± 0.24%, while DTX-PHPO released 70.49 ± 0.39% of the initial DTX amount within 48 h. Moreover, the physical stability of DTX-PHPO was increased due to the electrostatic interaction of the two peptides. The cellular uptake of DTX-PHPO in SGC-7901 cells and the cell killing effect tested on MCF-7 cells were enhanced by 2 folds at pH 6.8 compared to pH 7.4. Hence, DTX-PHPO is highly pH-sensitive in mildly acidic pH and exhibited

  16. New heparin–indomethacin conjugate with an ester linkage: Synthesis, self aggregation and drug delivery behavior

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nan-Nan; Zheng, Bing-Na [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Lin, Jian-Tao [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Guangdong Medical College, Dongguan 523808 (China); Zhang, Li-Ming, E-mail: ceszhlm@mail.sysu.edu.cn [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2014-01-01

    New heparin–indomethacin conjugate with an ester linkage was prepared by the carbodiimide-mediated condensation reaction, and then characterized by FTIR and {sup 1}HNMR analyses. Due to its amphiphilic character, such a conjugate could self-aggregate into spherical nanoparticles in aqueous system, as confirmed by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. By the in vitro drug release tests, the resultant conjugate nanoparticles were found to have a sustained and esterase-sensitive release behavior for conjugated indomethacin. In addition, the uptake of these conjugate nanoparticles into human nasopharyngeal carcinoma CNE1 cells was confirmed by fluorescence microscopy. - Highlights: • New heparin–indomethacin conjugate with an ester linkage was prepared. • Such a conjugate could self-aggregate into spherical nanoparticles in aqueous system. • The resultant conjugate nanoparticles exhibited an esterase-sensitive drug release behavior. • The resultant conjugate nanoparticles showed the cellular uptake ability in CNE1 cells.

  17. Subnanomolar antisense activity of phosphonate-peptide nucleic acid (PNA) conjugates delivered by cationic lipids to HeLa cells

    DEFF Research Database (Denmark)

    Shiraishi, Takehiko; Hamzavi, Ramin; Nielsen, Peter E

    2008-01-01

    oligomer. This modification of the PNA does not interfere with the nucleic acid target binding affinity based on thermal stability of the PNA/RNA duplexes. When delivered to cultured HeLa pLuc705 cells by Lipofectamine, the PNAs showed dose-dependent nuclear antisense activity in the nanomolar range...

  18. Blood compatibility of surfaces with immobilized albumin-heparin conjugate and effect of endothelial cell seeding on platelet adhesion

    NARCIS (Netherlands)

    Bos, G.W.; Bos, Gert W.; Scharenborg, Nicole M.; Poot, Andreas A.; Engbers, G.H.M.; Beugeling, T.; Beugeling, Tom; van Aken, W.G.; Feijen, Jan

    1999-01-01

    Endothelial cell (EC) seeding significantly improves the blood compatibility of artificial surfaces. Although a coating consisting of albumin and heparin (alb-hep) is a suitable substrate for seeded ECs, binding of ECs to the substrate further improves when small amounts of fibronectin are present

  19. Effect of a Fusion Peptide by Covalent Conjugation of a Mitochondrial Cell-Penetrating Peptide and a Glutathione Analog Peptide

    Directory of Open Access Journals (Sweden)

    Carmine Pasquale Cerrato

    2017-06-01

    Full Text Available Previously, we designed and synthesized a library of mitochondrial antioxidative cell-penetrating peptides (mtCPPs superior to the parent peptide, SS31, to protect mitochondria from oxidative damage. A library of antioxidative glutathione analogs called glutathione peptides (UPFs, exceptional in hydroxyl radical elimination compared with glutathione, were also designed and synthesized. Here, a follow-up study is described, investigating the effects of the most promising members from both libraries on reactive oxidative species scavenging ability. None of the peptides influenced cell viability at the concentrations used. Fluorescence microscopy studies showed that the fluorescein-mtCPP1-UPF25 (mtgCPP internalized into cells, and spectrofluorometric analysis determined the presence and extent of peptide into different cell compartments. mtgCPP has superior antioxidative activity compared with mtCPP1 and UPF25 against H2O2 insult, preventing ROS formation by 2- and 3-fold, respectively. Moreover, we neither observed effects on mitochondrial membrane potential nor production of ATP. These data indicate that mtgCPP is targeting mitochondria, protecting them from oxidative damage, while also being present in the cytosol. Our hypothesis is based on a synergistic effect resulting from the fused peptide. The mitochondrial peptide segment is targeting mitochondria, whereas the glutathione analog peptide segment is active in the cytosol, resulting in increased scavenging ability.

  20. Proliferation of endothelial cells on surface-immobilized albumin-heparin conjugate loaded with basic fibroblast growth factor

    NARCIS (Netherlands)

    Bos, Gert W.; Scharenborg, Nicole M.; Poot, André A.; Engbers, Gerard H.M.; Beugeling, Tom; Aken, van Willem G.; Feijen, Jan

    1999-01-01

    Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prostheses. Immobilization of basic fibroblast growth factor (bFGF) to substrates used to coat or fill porous prostheses may enhance the formation of a conflu

  1. Qualidade conjugal: mapeando conceitos

    Directory of Open Access Journals (Sweden)

    Clarisse Mosmann

    2006-12-01

    Full Text Available Apesar da ampla utilização do conceito de qualidade conjugal, identifica-se falta de clareza conceitual acerca das variáveis que o compõem. Esse artigo apresenta revisão da literatura na área com o objetivo de mapear o conceito de qualidade conjugal. Foram analisadas sete principais teorias sobre o tema: Troca Social, Comportamental, Apego, Teoria da Crise, Interacionismo Simbólico. Pelos postulados propostos nas diferentes teorias, podem-se identificar três grupos de variáveis fundamentais na definição da qualidade conjugal: recursos pessoais dos cônjuges, contexto de inserção do casal e processos adaptativos. Neste sentido, a qualidade conjugal é resultado do processo dinâmico e interativo do casal, razão deste caráter multidimensional.

  2. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  3. High-Performance Long-Term-Stable Dopant-Free Perovskite Solar Cells and Additive-Free Organic Solar Cells by Employing Newly Designed Multirole π-Conjugated Polymers.

    Science.gov (United States)

    Kranthiraja, Kakaraparthi; Gunasekar, Kumarasamy; Kim, Hyunji; Cho, An-Na; Park, Nam-Gyu; Kim, Seonha; Kim, Bumjoon J; Nishikubo, Ryosuke; Saeki, Akinori; Song, Myungkwan; Jin, Sung-Ho

    2017-06-01

    Perovskite solar cells (PSCs) and organic solar cells (OSCs) are promising renewable light-harvesting technologies with high performance, but the utilization of hazardous dopants and high boiling additives is harmful to all forms of life and the environment. Herein, new multirole π-conjugated polymers (P1-P3) are developed via a rational design approach through theoretical hindsight, further successfully subjecting them into dopant-free PSCs as hole-transporting materials and additive-free OSCs as photoactive donors, respectively. Especially, P3-based PSCs and OSCs not only show high power conversion efficiencies of 17.28% and 8.26%, but also display an excellent ambient stability up to 30 d (for PSCs only), owing to their inherent superior optoelectronic properties in their pristine form. Overall, the rational approach promises to support the development of environmentally and economically sustainable PSCs and OSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Inflammation Modulates RLIP76/RALBP1 Electrophile-Glutathione Conjugate Transporter and Housekeeping Genes in Human Blood-Brain Barrier Endothelial Cells.

    Directory of Open Access Journals (Sweden)

    Barbara Bennani-Baiti

    Full Text Available Endothelial cells are often present at inflammation sites. This is the case of endothelial cells of the blood-brain barrier (BBB of patients afflicted with neurodegenerative disorders such as Alzheimer's, Parkinson's, or multiple sclerosis, as well as in cases of bacterial meningitis, trauma, or tumor-associated ischemia. Inflammation is a known modulator of gene expression through the activation of transcription factors, mostly NF-κB. RLIP76 (a.k.a. RALBP1, an ATP-dependent transporter of electrophile-glutathione conjugates, modulates BBB permeability through the regulation of tight junction function, cell adhesion, and exocytosis. Genes and pathways regulated by RLIP76 are transcriptional targets of tumor necrosis factor alpha (TNF-α pro-inflammatory molecule, suggesting that RLIP76 may also be an inflammation target. To assess the effects of TNF-α on RLIP76, we faced the problem of choosing reference genes impervious to TNF-α. Since such genes were not known in human BBB endothelial cells, we subjected these to TNF-α, and measured by quantitative RT-PCR the expression of housekeeping genes commonly used as reference genes. We find most to be modulated, and analysis of several inflammation datasets as well as a metaanalysis of more than 5000 human tissue samples encompassing more than 300 cell types and diseases show that no single housekeeping gene may be used as a reference gene. Using three different algorithms, however, we uncovered a reference geneset impervious to TNF-α, and show for the first time that RLIP76 expression is induced by TNF-α and follows the induction kinetics of inflammation markers, suggesting that inflammation can influence RLIP76 expression at the BBB. We also show that MRP1 (a.k.a. ABCC1, another electrophile-glutathione transporter, is not modulated in the same cells and conditions, indicating that RLIP76 regulation by TNF-α is not a general property of glutathione transporters. The reference geneset

  5. Inflammation Modulates RLIP76/RALBP1 Electrophile-Glutathione Conjugate Transporter and Housekeeping Genes in Human Blood-Brain Barrier Endothelial Cells.

    Science.gov (United States)

    Bennani-Baiti, Barbara; Toegel, Stefan; Viernstein, Helmut; Urban, Ernst; Noe, Christian R; Bennani-Baiti, Idriss M

    2015-01-01

    Endothelial cells are often present at inflammation sites. This is the case of endothelial cells of the blood-brain barrier (BBB) of patients afflicted with neurodegenerative disorders such as Alzheimer's, Parkinson's, or multiple sclerosis, as well as in cases of bacterial meningitis, trauma, or tumor-associated ischemia. Inflammation is a known modulator of gene expression through the activation of transcription factors, mostly NF-κB. RLIP76 (a.k.a. RALBP1), an ATP-dependent transporter of electrophile-glutathione conjugates, modulates BBB permeability through the regulation of tight junction function, cell adhesion, and exocytosis. Genes and pathways regulated by RLIP76 are transcriptional targets of tumor necrosis factor alpha (TNF-α) pro-inflammatory molecule, suggesting that RLIP76 may also be an inflammation target. To assess the effects of TNF-α on RLIP76, we faced the problem of choosing reference genes impervious to TNF-α. Since such genes were not known in human BBB endothelial cells, we subjected these to TNF-α, and measured by quantitative RT-PCR the expression of housekeeping genes commonly used as reference genes. We find most to be modulated, and analysis of several inflammation datasets as well as a metaanalysis of more than 5000 human tissue samples encompassing more than 300 cell types and diseases show that no single housekeeping gene may be used as a reference gene. Using three different algorithms, however, we uncovered a reference geneset impervious to TNF-α, and show for the first time that RLIP76 expression is induced by TNF-α and follows the induction kinetics of inflammation markers, suggesting that inflammation can influence RLIP76 expression at the BBB. We also show that MRP1 (a.k.a. ABCC1), another electrophile-glutathione transporter, is not modulated in the same cells and conditions, indicating that RLIP76 regulation by TNF-α is not a general property of glutathione transporters. The reference geneset uncovered herein should

  6. Dual Functional Nanocarrier for Cellular Imaging and Drug Delivery in Cancer Cells Based on π-Conjugated Core and Biodegradable Polymer Arms.

    Science.gov (United States)

    Kulkarni, Bhagyashree; Surnar, Bapurao; Jayakannan, Manickam

    2016-03-14

    Multipurpose polymer nanoscaffolds for cellular imaging and delivery of anticancer drug are urgently required for the cancer therapy. The present investigation reports a new polymer drug delivery concept based on biodegradable polycaprolactone (PCL) and highly luminescent π-conjugated fluorophore as dual functional nanocarrier for cellular imaging and delivery vehicles for anticancer drug to cancer cells. To accomplish this goal, a new substituted caprolactone monomer was designed, and it was subjected to ring opening polymerization using a blue luminescent bishydroxyloligo-phenylenevinylene (OPV) fluorophore as an initiator. A series of A-B-A triblock copolymer building blocks with a fixed OPV π-core and variable chain biodegradable PCL arm length were tailor-made. These triblocks self-assembled in organic solvents to produce well-defined helical nanofibers, whereas in water they produced spherical nanoparticles (size ∼150 nm) with blue luminescence. The hydrophobic pocket of the polymer nanoparticle was found to be an efficient host for loading water insoluble anticancer drug such as doxorubicin (DOX). The photophysical studies revealed that there was no cross-talking between the OPV and DOX chromophores, and their optical purity was retained in the nanoparticle assembly for cellular imaging. In vitro studies revealed that the biodegradable PCL arm was susceptible to enzymatic cleavage at the intracellular lysosomal esterase under physiological conditions to release the loaded drugs. The nascent nanoparticles were found to be nontoxic to cancer cells, whereas the DOX-loaded nanoparticles accomplished more than 80% killing in HeLa cells. Confocal microscopic analysis confirmed the cell penetrating ability of the blue luminescent polymer nanoparticles and their accumulation preferably in the cytoplasm. The DOX loaded red luminescent polymer nanoparticles were also taken up by the cells, and the drug was found to be accumulated at the perinuclear environment

  7. Cell-penetrating peptides, novel synthetic nucleic acids, and regulation of gene function : Reconnaissance for designing functional conjugates

    OpenAIRE

    Guterstam, Peter

    2008-01-01

    Our genome operates by sending instructions, conveyed by mRNA, for the manufacture of proteins from chromosomal DNA in the nucleus of the cell to the protein synthesizing machinery in the cytoplasm. Alternative splicing is a natural process in which a single gene can encode multiple related proteins. During RNA splicing, introns are selectively removed resulting in alternatively spliced gene products. Alternatively spliced protein products can have very different biological effects, such that...

  8. Association between activation of phase 2 enzymes and down-regulation of dendritic cell maturation by c9,t11-conjugated linoleic acid.

    Science.gov (United States)

    Bergamo, Paolo; Maurano, Francesco; D'Arienzo, Rossana; David, Chella; Rossi, Mauro

    2008-05-15

    Antioxidant and cytoprotective enzymes (phase 2) exert protective activity against reactive oxygen species (ROS)-induced injury. We have recently shown how the beneficial effects of conjugated linoleic acid (CLA) in a mouse model of an autoimmune disease are parallel with the activation of phase 2 enzymes. In the present study we found that c9,t11-CLA isomer activates cytoprotective enzymes and down-regulates LPS- or gliadin-induced maturation in dendritic cells (DCs) obtained from a murine model of celiac disease. As expected, the enhancement of LPS-induced maturation (increased NFkappaB p65 nuclear translocation, CD86 expression and decreased CD11c+ cell number) was exacerbated by specific glutathione (GSH) inhibitor (buthionine sulphoximine; BSO). Conversely, the down-regulation of DC maturation by antioxidant N-acetylcysteine (NAC) was associated with the marked increase of intracellular thiol concentration. c9,t11-CLA activation of phase 2 enzymes in mouse DCs was observed first. Next, we found that the significant reduction of LPS- and gliadin-induced DC maturation in cultures pre-treated with c9,t11-CLA improved cellular redox status (decreased ROS and higher antioxidant defenses). Finally, the process of DC maturation triggered by gliadin, in contrast with that exhibited by LPS, was not associated with enhanced NFkappaB nuclear translocation and pro-inflammatory cytokines synthesis. These results demonstrate that c9,t11-CLA renders DCs more resistant to gliadin- or LPS-induced maturation, thus indicating that a cytoprotective mechanism elicited by c9,t11-CLA may modulate DC responsiveness.

  9. New application of a subcellular fractionation method to kidney and testis for the determination of conjugated linoleic acid in selected cell organelles of healthy and cancerous human tissues.

    Science.gov (United States)

    Hoffmann, Kristina; Blaudszun, Jörg; Brunken, Claus; Höpker, Wilhelm-Wolfgang; Tauber, Roland; Steinhart, Hans

    2005-03-01

    To clarify the mechanism of the anticarcinogenic effect of conjugated linoleic acid (CLA), its intracellular distribution needs to be determined. Subcellular fractionation using centrifugation techniques is a method that is frequently used for isolation of cell organelles from different tissues. But as the size and density of the organelles differ, the method needs to be optimised for every type of tissue. The novelty of this study is the application of a subcellular fractionation method to human healthy and cancerous renal and testicular tissue. Separation of total tissue homogenate into nuclei, cytosol, and a mixture of mitochondria and plasma membranes was achieved by differential centrifugation. As mitochondria and plasma membranes seemed to be too similar in size and weight to be separated by differential centrifugation, discontinuous density-gradient centrifugation was carried out successfully. The purity of the subcellular fractions was checked by measuring the activity of marker enzymes. All fractions were highly enriched in their corresponding marker enzyme. However, the nuclear fractions of kidney and renal cell carcinoma were slightly contaminated with mitochondria and plasma membrane fractions of all tissues with lysosomes. The fraction designated the cytosolic fraction contained not only cytosol, but also microsomes and lysosomes. The CLA contents of the subcellular fractions were in the range 0.13-0.37% of total fatty acids and were lowest in the plasma membrane fractions of all types of tissue studied. C16:0, C18:0, C18:1 c9, C18:2 n-6, and C20:4 n-6 were found to be the major fatty acids in all the subcellular fractions studied. However, marked variations in fatty acid content between subcellular fractions and between types of tissue were detectable. Because of these differences between tissues, no general statement on characteristic fatty acid profiles of single subcellular fractions is possible.

  10. A Novel Polysaccharide Conjugate from Bullacta exarata Induces G1-Phase Arrest and Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells.

    Science.gov (United States)

    Liao, Ningbo; Sun, Liang; Chen, Jiang; Zhong, Jianjun; Zhang, Yanjun; Zhang, Ronghua

    2017-03-01

    Bullacta exarata has been consumed in Asia, not only as a part of the normal diet, but also as a traditional Chinese medicine with liver- and kidney-benefitting functions. Several scientific investigations involving extraction of biomolecules from this mollusk and pharmacological studies on their biological activities have been carried out. However, little is known regarding the antitumor properties of polysaccharides from B. exarata, hence the polysaccharides from B. exarata have been investigated here. One polysaccharide conjugate BEPS-IA was isolated and purified from B. exarata. It mainly consisted of mannose and glucose in a molar ratio of 1:2, with an average molecular weight of 127 kDa. Thirteen general amino acids were identified to be components of the protein-bound polysaccharide. Methylation and NMR studies revealed that BEPS-IA is a heteropolysaccharide consisting of 1,4-linked-α-d-Glc, 1,6-linked-α-d-Man, 1,3,6-linked-α-d-Man, and 1-linked-α-d-Man residue, in a molar ratio of 6:1:1:1. In order to test the antitumor activity of BEPS-IA, we investigated its effect against the growth of human hepatocellular carcinoma cells HepG2 in vitro. The result showed that BEPS-IA dose-dependently exhibited an effective HepG2 cells growth inhibition with an IC50 of 112.4 μg/mL. Flow cytometry analysis showed that BEPS-IA increased the populations of both apoptotic sub-G1 and G1 phase. The result obtained from TUNEL assay corroborated apoptosis which was shown in flow cytometry. Western blot analysis suggested that BEPS-IA induced apoptosis and growth inhibition were associated with up-regulation of p53, p21 and Bax, down-regulation of Bcl-2. These findings suggest that BEPS-IA may serve as a potential novel dietary agent for hepatocellular carcinoma.

  11. Photoconductive properties of conjugated polymers

    CERN Document Server

    Halls, J J M

    1997-01-01

    The research described in my dissertation has involved the fabrication and characterisation of photovoltaic cells based on conjugated polymers, including the widely studied polymer poly(p-phenylenevinylene). These materials have semiconducting properties which arise from the delocalisation of electrons along the pi-electron systems of the polymer chains. Research into these materials is motivated both by their novel electronic properties, and also their potential for use in a wide range of applications including light-emitting diodes (LEDs), thin-film transistors, and photovoltaic cells (solar cells and light detectors). Light absorbed in a photovoltaic cell generates opposite charges which are collected at two different electrodes, giving rise to an electric current

  12. Prospective Preliminary In Vitro Investigation of a Magnetic Iron Oxide Nanoparticle Conjugated with Ligand CD80 and VEGF Antibody As a Targeted Drug Delivery System for the Induction of Cell Death in Rodent Osteosarcoma Cells.

    Science.gov (United States)

    Kovach, AnneMarie Kay; Gambino, Jen M; Nguyen, Vina; Nelson, Zach; Szasz, Taylor; Liao, Jun; Williams, Lakiesha; Bulla, Sandra; Prabhu, Raj

    2016-01-01

    Target drug deliveries using nanotechnology are a novel consideration in the treatment of cancer. We present herein an in vitro mouse model for the preliminary investigation of the efficacy of an iron oxide nanoparticle complex conjugated to vascular endothelial growth factor (VEGF) antibody and ligand cluster of differentiation 80 (CD80) for the purpose of eventual translational applications in the treatment of human osteosarcoma (OSA). The 35 nm diameter iron oxide magnetic nanoparticles are functionalized with an n-hydroxysuccinimide biocompatible coating and are conjugated on the surface to proteins VEGF antibody and ligand CD80. Combined, these proteins have the ability to target OSA cells and induce apoptosis. The proposed system was tested on a cancerous rodent osteoblast cell line (ATCCTM(NPO) CRL-2836) at four different concentrations (0.1, 1.0, 10.0, and 100.0 μg/mL) of ligand CD80 alone, VEGF antibody alone, and a combination thereof (CD80+VEGF). Systems were implemented every 24 h over different sequential treatment timelines: 24, 48, and 72 h, to find the optimal protein concentration required for a reduction in cell proliferation. Results demonstrated that a combination of ligand CD80 and VEGF antibody was consistently most effective at reducing aberrant osteoblastic proliferation for both the 24- and 72-h timelines. At 48 h, however, an increase in cell proliferation was documented for the 0.1 and 1 μg/mL groups. For the 24- and 72-h tests, concentrations of 1.0 μg/mL of CD80+VEGF and 0.1 μg/mL of VEGF antibody were most effective. Concentrations of 10.0 and 100.0 μg/mL of CD80+VEGF reduced cell proliferation, but not as remarkably as the 1.0 μg/mL concentration. In addition, cell proliferation data showed that multiple treatments (72-h test) induced cell death in the osteoblasts better than a single treatment. Future targeted drug delivery system research includes trials in OSA cell lines from greater phylum species having

  13. Prospective Preliminary In Vitro Investigation of a Magnetic Iron Oxide Nanoparticle Conjugated with Ligand CD80 and VEGF Antibody As a Targeted Drug Delivery System for the Induction of Cell Death in Rodent Osteosarcoma Cells

    Directory of Open Access Journals (Sweden)

    Anne Marie Kay Kovach

    2016-10-01

    Full Text Available Target drug deliveries using nanotechnology are a novel consideration in the treatment of cancer. We present herein an in vitro mouse model for the preliminary investigation of the efficacy of an iron oxide nanoparticle complex conjugated to vascular endothelial growth factor (VEGF antibody and ligand cluster of differentiation 80 (CD80 for the purpose of eventual translational applications in the treatment of human osteosarcoma (OSA. The 35 nm diameter iron oxide magnetic nanoparticles are functionalized with an n-hydroxysuccinimide biocompatible coating and are conjugated on the surface to proteins VEGF antibody and ligand CD80. Combined, these proteins have the ability to target OSA cells and induce apoptosis. The proposed system was tested on a cancerous rodent osteoblast cell line (ATCCTMNPO CRL-2836 at four different concentrations (0.1, 1.0, 10.0, and 100.0 μg/mL of ligand CD80 alone, VEGF antibody alone, and a combination thereof (CD80+VEGF. Systems were implemented every 24 h over different sequential treatment timelines: 24, 48, and 72 h, to find the optimal protein concentration required for a reduction in cell proliferation. Results demonstrated that a combination of ligand CD80 and VEGF antibody was consistently most effective at reducing aberrant osteoblastic proliferation for both the 24- and 72-h timelines. At 48 h, however, an increase in cell proliferation was documented for the 0.1 and 1 μg/mL groups. For the 24- and 72-h tests, concentrations of 1.0 μg/mL of CD80+VEGF and 0.1 μg/mL of VEGF antibody were most effective. Concentrations of 10.0 and 100.0 μg/mL of CD80+VEGF reduced cell proliferation, but not as remarkably as the 1.0 μg/mL concentration. In addition, cell proliferation data showed that multiple treatments (72-h test induced cell death in the osteoblasts better than a single treatment. Future targeted drug delivery system research includes trials in OSA cell lines from greater phylum

  14. Electroporation-based delivery of cell-penetrating peptide conjugates of peptide nucleic acids for antisense inhibition of intracellular bacteria.

    Science.gov (United States)

    Ma, Sai; Schroeder, Betsy; Sun, Chen; Loufakis, Despina Nelie; Cao, Zhenning; Sriranganathan, Nammalwar; Lu, Chang

    2014-10-01

    Cell penetrating peptides (CPPs) have been used for a myriad of cellular delivery applications and were recently explored for delivery of antisense agents such as peptide nucleic acids (PNAs) for bacterial inhibition. Although these molecular systems (i.e. CPP-PNAs) have shown ability to inhibit growth of bacterial cultures in vitro, they show limited effectiveness in killing encapsulated intracellular bacteria in mammalian cells such as macrophages, presumably due to difficulty involved in the endosomal escape of the reagents. In this report, we show that electroporation delivery dramatically increases the bioavailability of CPP-PNAs to kill Salmonella enterica serovar Typhimurium LT2 inside macrophages. Electroporation delivers the molecules without involving endocytosis and greatly increases the antisense effect. The decrease in the average number of Salmonella per macrophage under a 1200 V cm(-1) and 5 ms pulse was a factor of 9 higher than that without electroporation (in an experiment with a multiplicity of infection of 2 : 1). Our results suggest that electroporation is an effective approach for a wide range of applications involving CPP-based delivery. The microfluidic format will allow convenient functional screening and testing of PNA-based reagents for antisense applications.

  15. Synthesis, characterization and biological activity of Rhein-cyclodextrin conjugate

    Science.gov (United States)

    Liu, Manshuo; Lv, Pin; Liao, Rongqiang; Zhao, Yulin; Yang, Bo

    2017-01-01

    Cyclodextrin conjugate complexation is a useful method to enhance the solubility and absorption of poorly soluble drugs. A series of new Rhein-β-cyclodextrin conjugates (Rh-CD conjugates) have been synthesized and examined. Rhein is covalently linked with the β-CD by amido linkage in a 1:1 molar ratio. The conjugates were characterized by 1H NMR, 13C NMR, HRMS, powder X-ray diffraction (powder XRD) as well as thermogravimetric analysis (TGA). The results reveal that incorporation of β-CD could improve the aqueous solubility of Rhein and the cytotoxicity against hepatocellular carcinoma (HepG2) cell line as well as antibacterial activity against three organisms. The improved biological activity and the satisfactory water solubility of the conjugates will be potentially useful for developing novel drug-cyclodextrin conjugates, such as herbal medicine.

  16. Theoretical study of conjugated porphyrin polymers

    DEFF Research Database (Denmark)

    Pedersen, T.G.; Lynge, T.B.; Kristensen, P.K.

    2005-01-01

    The optical gap of conjugated triply linked porphyrin chains is exceptionally low (similar to 0.5 eV). Hence, such chains are candidates for organic infrared detectors and solar cells harvesting the infrared part of the solar spectrum. However, a low exciton binding energy is required for these a......The optical gap of conjugated triply linked porphyrin chains is exceptionally low (similar to 0.5 eV). Hence, such chains are candidates for organic infrared detectors and solar cells harvesting the infrared part of the solar spectrum. However, a low exciton binding energy is required...... for these applications. From a theoretical analysis of excitons in long metalloporphyrin chains, we demonstrate that the binding energy is much lower than in usual conjugated polymers. Our calculated absorption spectra are in good agreement with measurements. (c) 2004 Elsevier B.V. All rights reserved....

  17. Methotrexate and epirubicin conjugates as potential antitumor drugs

    Directory of Open Access Journals (Sweden)

    Szymon Wojciech Kmiecik

    2017-07-01

    Full Text Available Introduction: The use of hybrid molecules has become one of the most significant approaches in new cytotoxic drug design. This study describes synthesis and characterization of conjugates consisting of two well-known and characterized chemotherapeutic agents: methotrexate (MTX and epirubicin (EPR. The synthesized conjugates combine two significant anticancer strategies: combinatory therapy and targeted therapy. These two drugs were chosen because they have different mechanisms of action, which can increase the anticancer effect of the obtained conjugates. MTX, which is a folic acid analog, has high cytotoxic properties and can serve as a targeting moiety that can reach folate receptors (FRs overexpresing tumor cells. Combination of nonselective drugs such as EPR with MTX can increase the selectivity of the obtained conjugates, while maintaining the high cytotoxic properties.Materials and methods: Conjugates were purified by RP-HPLC and the structure was investigated by MS and MS/MS methods. The effect of the conjugates on proliferation of LoVo, LoVo/Dx, MCF-7 and MV-4-11 human cancer cell lines was determined by SRB or MTT assay.Results: The conjugation reaction results in the formation of monosubstituted (α, γ and disubstituted MTX derivatives. In vitro proliferation data demonstrate that the conjugates synthesized in our study show lower cytotoxic properties than both chemotherapeutics used alone.Discussion: Epirubicin cytotoxicity was not observed in obtained conjugates. Effective drugs release after internalization needs further investigation.

  18. Studies in Multifunctional Drug Development: Preparation and Evaluation of 11beta-Substituted Estradiol-Drug Conjugates, Cell Membrane Targeting Imaging Agents, and Target Multifunctional Nanoparticles

    Science.gov (United States)

    Dao, KinhLuan Lenny D.

    Cancer is the second leading cause of death after cardiovascular disease in the United State. Despite extensive research in development of antitumor drugs, most of these therapeutic entities often possess nonspecific toxicity, thus they can only be used to treat tumors in higher doses or more frequently. Because of the cytotoxicity and severe side effects, the drug therapeutic window normally is limited. Beside the toxicity issue, antitumor drug are also not selectively taken up by tumor cells, thus the necessitating concentrations that would eradicate the tumor can often not be used. In addition, tumor cells tend to develop resistance against the anticancer drugs after prolonged treatment. Therefore, alleviating the systemic cytotoxicity and side effects, improving in tumor selectivity, high potency, and therapeutic efficacy are still major obstacles in the area of anticancer drug development. A more promising approach for developing a selective agent for cancer is to conjugate a potent therapeutic drug, or an imaging agent with a targeting group, such as antibody or a high binding-specificity small molecule, that selectively recognize the overexpressed antigens or proteins on tumor cells. My research combines several approaches to describe this strategy via using different targeting molecules to different diseases, as well as different potent cytotoxic drugs for different therapies. Three studies related to the preparation and biological evaluation of new therapeutic agents, such as estradiol-drug hybrids, cell membrane targeted molecular imaging agents, and multifunctional NPs will be discussed. The preliminary results of these studies indicated that our new reagents achieved their initial objectives and can be further improved for optimized synthesis and in vivo experiments. The first study describes the method in which we employed a modular assembly approach to synthesize a novel 11beta-substituted steroidal anti-estrogen. The key intermediate was synthesized

  19. Quantitative profiling of 4'-geranyloxyferulic acid and its conjugate with l-nitroarginine methyl ester in mononuclear cells by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Taddeo, Vito Alessandro; Genovese, Salvatore; Carlucci, Giuseppe; Ferrone, Vincenzo; Patruno, Antonia; Ferrone, Alessio; de Medina, Philippe; Fiorito, Serena; Epifano, Francesco

    2017-01-30

    Oxyprenylated natural products were shown to exert in vitro and in vivo remarkable anti-cancer and anti-inflammatory effects. This paper describes a rapid, selective, and sensitive HPLC method with fluorescence detection for determination of 4'-geranyloxyferulic acid (GOFA) and its conjugate with l-nitroarginine methyl ester (GOFA-L-NAME) in mononuclear cells. Analytes were extracted from cells using methanol and eluted on a GraceSmart RP18 analytical column (250×4.6mm i.d., 5μm particle size) kept at 25°C. A mixture of formic acid 1% in water (A) and methanol (B) were used as mobile phase, at a flow-rate of 1.2mL/min in gradient elution. A fluorescence detector (excitation/emission wavelength of 319/398nm for GOFA and GOFA-L-NAME), was used for the two analytes. Calibration curves of GOFA and GOFA-L-NAME were linear over the concentration range of 1.0-50μg/mL, with correlation coefficients (r(2))≥0.9995. Intra- and inter-assay precision do not exceed 6.8%. The accuracy was from 94% to 105% for quality control samples (2.0, 25.0 and 40μg/mL). The mean (RSD%) extraction recoveries (n=5) for GOFA and GOFA-L-NAME from spiked cells at 2.0, 25.0 and 40.0μg/mL were 92.4±1.5%, 94.7±0.9% and 93.8±1.1%, for GOFA and 95.3±1.2%, 94.8±1.0% and 93.9±1.3%, for GOFA-L-NAME. The limits of detection and quantification were 0.3μg/mL and 1.0μg/mL for GOFA and GOFA-L-NAME. This method was successfully applied to measure GOFA and GOFA-L-NAME concentrations in a mononuclear cells.

  20. Synthesis and Characterization of Carbazole-Benzothiadiazole-Based Conjugated Polymers for Organic Photovoltaic Cells with Triazole in the Main Chain

    Directory of Open Access Journals (Sweden)

    Eunhee Lim

    2013-01-01

    Full Text Available We have synthesized a series of carbazole-benzothiadiazole-triazole based copolymers, poly[(N-9′-heptadecanyl-2,7-carbazole-co-(5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole-co-((4-(4-butylphenyl-3,5-diphenyl-4H-1,2,4]triazole] (PCz3TBTz by Suzuki coupling polymerization. The optical and electrochemical properties of the copolymers could be tuned by changing the comonomer unit of triazole from 0% to 80%. Organic photovoltaic (OPV cells were fabricated by blending the synthesized polymers as a donor and PCBM as an acceptor. The material solubility and film morphology were improved by introducing the triazole unit in the main chain. Improved OPV device performance of 1.74% was achieved in the presence of an optimal amount of triazole moieties.

  1. A stability study of polymer solar cells using conjugated polymers with different donor or acceptor side chain patterns

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria; Kesters, Jurgen; Defour, Maxime

    2016-01-01

    Improvement of the power conversion efficiency and long term stability remains to be of crucial importance for the further development of polymer solar cells (PSCs). Herein, a donor-acceptor copolymer based on 4,8-di(thiophene-2′-yl)benzo[1,2-b:4,5-b′]dithiophene (DTBDT) and 4,7-di(thiophene-2′-y...... in an improved photochemical stability of the polymer film and a higher efficiency of 5.6% for the spin-coated PSC. The stability of roll-coated devices also slightly increases with the incorporation of 10% of either the 2-hydroxyethyl or 2-phenylethyl side chain....

  2. Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores

    KAUST Repository

    Zhang, Siyuan

    2017-09-05

    Two intermediate-sized donor molecules, BBTz-X and BDT-X, have been synthesized by the Stille coupling between 4-(4,4-bis(2-ethylhexyl)-6-(trimethylstannyl)-4H-silolo[3,2-b:4,5-b′]dithiophen-2-yl)-7-(5′-hexyl-[2,2′-bithiophen]-5-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine and either 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diiodobenzo[1,2-d:4,5-d′]bis(thiazole) or 2,6-dibromo-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene, respectively. Both oxidation and reduction potentials for BBTz-X are anodically shifted relative to those for BDT-X, but the oxidation potential is more sensitive to the identity of the core; this is consistent with what is seen for DFT-calculated HOMO and LUMO energies and with a slightly blue-shifted absorption maximum for BBTz-X. Although DFT calculations, along with crystal structures of related compounds, suggest more planar molecular structures for BBTz-X than for BDT-X, film structures and the effects of various annealing processes on these films, as revealed by GIWAXS, are similar. The performance of BDT-X:PC61BM bulk-heterojunction solar cells is more sensitive to annealing conditions than that of BBTz-X:PC61BM cells, but under appropriate conditions, both yield power conversion efficiencies of >7%.

  3. Evolution of conjugation and type IV secretion systems.

    Science.gov (United States)

    Guglielmini, Julien; de la Cruz, Fernando; Rocha, Eduardo P C

    2013-02-01

    Genetic exchange by conjugation is responsible for the spread of resistance, virulence, and social traits among prokaryotes. Recent works unraveled the functioning of the underlying type IV secretion systems (T4SS) and its distribution and recruitment for other biological processes (exaptation), notably pathogenesis. We analyzed the phylogeny of key conjugation proteins to infer the evolutionary history of conjugation and T4SS. We show that single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) conjugation, while both based on a key AAA(+) ATPase, diverged before the last common ancestor of bacteria. The two key ATPases of ssDNA conjugation are monophyletic, having diverged at an early stage from dsDNA translocases. Our data suggest that ssDNA conjugation arose first in diderm bacteria, possibly Proteobacteria, and then spread to other bacterial phyla, including bacterial monoderms and Archaea. Identifiable T4SS fall within the eight monophyletic groups, determined by both taxonomy and structure of the cell envelope. Transfer to monoderms might have occurred only once, but followed diverse adaptive paths. Remarkably, some Firmicutes developed a new conjugation system based on an atypical relaxase and an ATPase derived from a dsDNA translocase. The observed evolutionary rates and patterns of presence/absence of specific T4SS proteins show that conjugation systems are often and independently exapted for other functions. This work brings a natural basis for the classification of all kinds of conjugative systems, thus tackling a problem that is growing as fast as genomic databases. Our analysis provides the first global picture of the evolution of conjugation and shows how a self-transferrable complex multiprotein system has adapted to different taxa and often been recruited by the host. As conjugation systems became specific to certain clades and cell envelopes, they may have biased the rate and direction of gene transfer by conjugation within prokaryotes.

  4. Phase conjugation of high energy lasers.

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, David E; Valley, Michael T.; Atherton, Briggs W.; Bigman, Verle Howard; Boye, Lydia Ann; Broyles, Robin Scott; Kimmel, Mark W.; Law, Ryan J.; Yoder, James R.

    2013-01-01

    In this report we explore claims that phase conjugation of high energy lasers by stimulated Brillouin scattering (SBS) can compensate optical aberrations associated with severely distorted laser amplifier media and aberrations induced by the atmosphere. The SBS media tested was a gas cell pressurized up to 300 psi with SF6 or Xe or both. The laser was a 10 Hz, 3J, Q-switched Nd:YAG with 25 ns wide pulses. Atmospheric aberrations were created with space heaters, helium jets and phase plates designed with a Kolmogorov turbulence spectrum characterized by a Fried parameter, ro , ranging from 0.6 6.0 mm. Phase conjugate tests in the laboratory were conducted without amplification. For the strongest aberrations, D/ro ~ 20, created by combining the space heaters with the phase plate, the Strehl ratio was degraded by a factor of ~50. Phase conjugation in SF6 restored the peak focusable intensity to about 30% of the original laser. Phase conjugate tests at the outdoor laser range were conducted with laser amplifiers providing gain in combination with the SBS cell. A large 600,000 BTU kerosene space heater was used to create turbulence along the beam path. An atmospheric structure factor of Cn2 = 5x10-13 m2/3 caused the illumination beam to expand to a diameter 250mm and overfill the receiver. The phase conjugate amplified return could successfully be targeted back onto glints 5mm in diameter. Use of a lenslet arrays to lower the peak focusable intensity in the SBS cell failed to produce a useful phase conjugate beam; The Strehl ratio was degraded with multiple random lobes instead of a single focus. I will review literature results which show how multiple beams can be coherently combined by SBS when a confocal reflecting geometry is used to focus the laser in the SBS cell.

  5. Interplay of alternative conjugated pathways and steric interactions on the electronic and optical properties of donor-acceptor conjugated polymers

    KAUST Repository

    Lima, Igo T.

    2014-01-01

    Donor-acceptor π-conjugated copolymers are of interest for a wide range of electronic applications, including field-effect transistors and solar cells. Here, we present a density functional theory (DFT) study of the impact of varying the conjugation pathway on the geometric, electronic, and optical properties of donor-acceptor systems. We consider both linear ("in series"), traditional conjugation among the donor-acceptor moieties versus structures where the acceptor units are appended orthogonally to the linear, donor-only conjugated backbone. Long-range-corrected hybrid functionals are used in the investigation with the values of the tuned long-range separation parameters providing an estimate of the extent of conjugation as a function of the oligomer architecture. Considerable differences in the electronic and optical properties are determined as a function of the nature of the conjugation pathway, features that should be taken into account in the design of donor-acceptor copolymers.

  6. Hybrid thin-film solar cells comprising mesoporous titanium dioxide and conjugated polymers; Hybride Duennschicht-Solarzellen aus mesoporoesem Titandioxid und konjugierten Polymeren

    Energy Technology Data Exchange (ETDEWEB)

    Schattauer, Sylvia

    2010-12-01

    The main objective of this thesis is to study the active components and their interactions in so called organic hybrid solar cells. These consist of a thin inorganic titanium dioxide layer, combined with a polymer layer. In general, the efficiency of these hybrid solar cells is determined by the light absorption in the donor polymer, the dissociation of excitons at the heterojunction between TiO{sub 2} and polymer, as well as the generation and extraction of free charge carriers. To optimize the solar cells, the physical interactions between the materials are modified and the influences of various preparation parameters are systematically investigated. Among others, important findings regarding the optimal use of materials and preparation conditions as well as detailed investigations of fundamental factors such as film morphology and polymer infiltration are presented in more detail. First, a variety of titanium dioxide layer were produced, from which a selection for use in hybrid solar cells was made. The obtained films show differences in surface structure, film morphology and crystallinity, depending on the way how the TiO{sub 2} layer has been prepared. All these properties of the TiO{sub 2} films may strongly affect the performance of the hybrid solar cells, by influencing e.g. the exciton diffusion length, the efficiency of exciton dissociation at the hybrid interface, and the carrier transport properties. Detailed investigations were made for mesoporous TiO{sub 2} layer following a new nanoparticle synthesis route, which allows to produce crystalline particles during the synthesis. As donor component, conjugated polymers, either derivatives of cyclohexylamino-poly(p-phenylene vinylene) (PPV) or a thiophene are used. The preparation routine also includes a thermal treatment of the TiO{sub 2} layers, revealing a temperature-dependent change in morphology, but not of the crystal structure. The effects on the solar cell properties have been documented and

  7. N-(2-Hydroxypropyl)methacrylamide-based polymer conjugates with pH-controlled activation of doxorubicin for cell-specific or passive tumour targeting. Synthesis by RAFT polymerisation and physicochemical characterisation.

    Science.gov (United States)

    Chytil, Petr; Etrych, Tomáš; Kříž, Jaroslav; Subr, Vladimír; Ulbrich, Karel

    2010-11-20

    Controlled radical reversible addition-fragmentation chain transfer (RAFT) polymerisation was used to prepare water-soluble polymer-drug carriers based on copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) with a hydrazide group-containing monomer, showing well-defined structure with narrow molecular weight distribution (approx. 1.1-1.2). The anticancer therapeutic doxorubicin was bound to the polymeric carrier by a hydrazone bond, enabling pH-controlled release under mildly acid conditions that mimics the environment in endosomes/lysosomes of tumour cells. RAFT polymerisation facilitated the synthesis of semitelechelic copolymers, which were used in the synthesis of monoclonal anti-CD20 antibody-polymer-drug conjugate designed for cell-specific tumour targeting. They were also used for producing a biodegradable high-molecular-weight graft polymer-drug conjugate that degrade in the presence of glutathione, which is designed for passive targeting to solid tumours. The conjugates exhibited well-defined structures with narrow molecular weight distributions of approx. 1.3 and pH-controlled drug release.

  8. Cancer Cell Targeting Using Folic Acid/Anti-HER2 Antibody Conjugated Fluorescent CdSe/CdS/ZnS-Mercaptopropionic Acid and CdTe-Mercaptosuccinic Acid Quantum Dots.

    Science.gov (United States)

    Singh, Gurpal; Kumar, Manoj; Soni, Udit; Arora, Vikas; Bansal, Vivek; Gupta, Dikshi; Bhat, Madhusudan; Dinda, Amit K; Sapra, Sameer; Singh, Harpal

    2016-01-01

    CdSe/CdS/ZnS and CdTe quantum dots (QDs) were synthesized by successive ion layer adsorption and reaction (SILAR) technique and direct aqueous synthesis respectively using thiol stabilizers. Synthesized CdSe/CdS/ZnS and CdTe QDs stabilized with 3-mercaptopropionic acid (MPA) and mercaptosuccinic acid (MSA) were used as fluorescent labels after conjugation with folic acid (FA) and anti-HER2 antibodies. Photoluminescence quantum yield of folated CdSe/CdS/ZnS-MPA and CdTe-MSA QDs was 59% and 77% than that of non-folated hydrophilic QDs. The folate receptor-mediated delivery of folic acid-conjugated CdTe-MSA and CdSe/CdS/ZnS-MPA QDs showed higher cellular internalization as observed by confocal laser scanning microscopic studies. Folated and non-folated CdTe-MSA QDs were highly toxic and exhibited only 10% cell viability as compared to > 80% cell viability with CdSe/CdS/ZnS-MPA QDs over the concentration ranging from 3.38 to 50 pmoles. Immunohistochemistry (IHC) results of human breast cancer tissue samples showed positive results with anti-HER2 antibody conjugated CdSe/CdS/ZnS-MPA QDs with better sensitivity and specificity as compared to conventional IHC analysis using diaminobenzedene staining.

  9. Screening π-conjugated bridges of organic dyes for dye-sensitized solar cells with panchromatic visible light harvesting

    Science.gov (United States)

    Yang, Zhenqing; Liu, Chunmeng; Shao, Changjin; Zeng, Xiaofei; Cao, Dapeng

    2016-07-01

    Developing highly efficient organic dyes with panchromatic visible light harvesting for dye-sensitized solar cells (DSSCs) is still one of the most important scientific challenges. Here, we design a series of phenothiazine derivative organic dyes with donor-π-acceptor (D-π-A) structure using density functional theory (DFT) and time-dependent DFT (TDDFT) based on experimentally synthesized typical SH-6 organic dyes. Results indicate that the newly designed BUCT13 - BUCT30 dyes show smaller HOMO-LUMO energy gaps, higher molar extinction coefficients and obvious redshifts compared to the SH-6 dye, and the maximum absorption peaks of eight dyes are greater than 650 nm among the newly designed dyes. In particular, BUCT27 exhibits a 234 nm redshift and the maximum molar extinction coefficient with an increment of about 80% compared to the SH-6 dye. BUCT19 exhibits not only a 269 nm redshift and higher molar extinction coefficient with an increment of about 50% compared to the SH-6 dye, but the extremely broad absorption spectrum covering the entire visible range up to the near-IR region of 1200 nm. It is expected that this work can provide a new strategy and guidance for the investigation of these dye-sensitized devices.

  10. Characterization of local electrochemical doping of high performance conjugated polymer for photovoltaics using scanning droplet cell microscopy.

    Science.gov (United States)

    Gasiorowski, Jacek; Mardare, Andrei Ionut; Sariciftci, Niyazi Serdar; Hassel, Achim Walter

    2013-12-15

    The electrochemical oxidation of a next generation low bandgap high performance photovoltaic material namely poly[4,8-bis-substituted-benzo[1,2-b:4,5-b0]dithiophene-2,6-diyl-alt-4-substituted-thieno[3,4-b] thiophene-2,6-diyl] (PBDTTT-c) thin film was investigated using a scanning droplet cell microscope. Cyclic voltammetry was used for the basic characterization of the oxidation/doping of PBDTTT-c. Application of the different final potentials during the electrochemical study provides a close look to the oxidation kinetics. The electrical properties of both doped and undoped PBDTTT-c were analyzed in situ by electrochemical impedance spectroscopy giving the possibility to correlate the changes in the doping level with the subsequent changes in the resistance and capacitance. As a result one oxidation peak was found during the cyclic voltammetry and in potentiostatic measurements. From Mott-Schottky analysis a donor concentration of 2.3 × 10(20) cm(-3) and a flat band potential of 1.00 V vs. SHE were found. The oxidation process resulted in an increase of the conductivity by two orders of magnitude reaching a maximum for the oxidized form of 1.4 S cm(-1).

  11. Characterization of local electrochemical doping of high performance conjugated polymer for photovoltaics using scanning droplet cell microscopy☆

    Science.gov (United States)

    Gasiorowski, Jacek; Mardare, Andrei Ionut; Sariciftci, Niyazi Serdar; Hassel, Achim Walter

    2013-01-01

    The electrochemical oxidation of a next generation low bandgap high performance photovoltaic material namely poly[4,8-bis-substituted-benzo[1,2-b:4,5-b0]dithiophene-2,6-diyl-alt-4-substituted-thieno[3,4-b] thiophene-2,6-diyl] (PBDTTT-c) thin film was investigated using a scanning droplet cell microscope. Cyclic voltammetry was used for the basic characterization of the oxidation/doping of PBDTTT-c. Application of the different final potentials during the electrochemical study provides a close look to the oxidation kinetics. The electrical properties of both doped and undoped PBDTTT-c were analyzed in situ by electrochemical impedance spectroscopy giving the possibility to correlate the changes in the doping level with the subsequent changes in the resistance and capacitance. As a result one oxidation peak was found during the cyclic voltammetry and in potentiostatic measurements. From Mott–Schottky analysis a donor concentration of 2.3 × 1020 cm−3 and a flat band potential of 1.00 V vs. SHE were found. The oxidation process resulted in an increase of the conductivity by two orders of magnitude reaching a maximum for the oxidized form of 1.4 S cm−1. PMID:25843970

  12. Interaction of hesperetin glucuronide conjugates with human BCRP, MRP2 and MRP3 as detected in membrane vesicles of overexpressing baculovirus-infected Sf9 cells.

    Science.gov (United States)

    Brand, Walter; Oosterhuis, Berend; Krajcsi, Peter; Barron, Denis; Dionisi, Fabiola; van Bladeren, Peter J; Rietjens, Ivonne M C M; Williamson, Gary

    2011-12-01

    The citrus flavonoid hesperetin (4'-methoxy-3',5,7-trihydroxyflavanone) is the aglycone of hesperidin, the major flavonoid present in sweet oranges. Hesperetin 7-O-glucuronide (H7G) and hesperetin 3'-O-glucuronide (H3'G) are the two most abundant metabolites of hesperetin in vivo. In this study, their interaction with specific ABC transporters, believed to play a role in the disposition and bioavailability of hesperetin, was studied using Sf9 membranes from cells overexpressing human BCRP (ABCG2), MRP2 (ABCC2) and MRP3 (ABCC3). Both H7G and H3'G were tested for their potential to activate and inhibit ATPase activity, and to inhibit vesicular transport by these transporters. Both H7G and H3'G demonstrated interaction with all tested ABC transporters, especially with BCRP and MRP3. An interesting difference between H7G and H3'G was seen with respect to the interaction with BCRP: H7G stimulated the ATPase activity of BCRP up to 76% of the maximal effect generated by the reference activator sulfasalazine, with an EC(50) of 0.45 µM, suggesting that H7G is a high affinity substrate of BCRP, whereas H3'G did not stimulate BCRP ATPase activity. Only moderate inhibition of BCRP ATPase activity at high H3'G concentrations was observed. This study provides information on the potential of hesperetin glucuronide conjugates to act as specific ABC transporter substrates or inhibitors and indicates that regio-specific glucuronidation could affect the disposition of hesperetin.

  13. Polysaccharide-specific memory B cells generated by conjugate vaccines in humans conform to the CD27+IgG+ isotype-switched memory B Cell phenotype and require contact-dependent signals from bystander T cells activated by bacterial proteins to differentiate into plasma cells.

    Science.gov (United States)

    Clarke, Edward T; Williams, Neil A; Findlow, Jamie; Borrow, Ray; Heyderman, Robert S; Finn, Adam

    2013-12-15

    The polysaccharides (PS) surrounding encapsulated bacteria are generally unable to activate T cells and hence do not induce B cell memory (BMEM). PS conjugate vaccines recruit CD4(+) T cells via a carrier protein, such as tetanus toxoid (TT), resulting in the induction of PS-specific BMEM. However, the requirement for T cells in the subsequent activation of the BMEM at the time of bacterial encounter is poorly understood, despite having critical implications for protection. We demonstrate that the PS-specific BMEM induced in humans by a meningococcal serogroup C PS (Men C)-TT conjugate vaccine conform to the isotype-switched (IgG(+)CD27(+)) rather than the IgM memory (IgM(+)CD27(+)) phenotype. Both Men C and TT-specific BMEM require CD4(+) T cells to differentiate into plasma cells. However, noncognate bystander T cells provide such signals to PS-specific BMEM with comparable effect to the cognate T cells available to TT-specific BMEM. The interaction between the two populations is contact-dependent and is mediated in part through CD40. Meningococci drive the differentiation of the Men C-specific BMEM through the activation of bystander T cells by bacterial proteins, although these signals are enhanced by T cell-independent innate signals. An effect of the TT-specific T cells activated by the vaccine on unrelated BMEM in vivo is also demonstrated. These data highlight that any protection conferred by PS-specific BMEM at the time of bacterial encounter will depend on the effectiveness with which bacterial proteins are able to activate bystander T cells. Priming for T cell memory against bacterial proteins through their inclusion in vaccine preparations must continue to be pursued.

  14. Synthesis and biological evaluation of benzimidazole-oxindole conjugates as microtubule-targeting agents.

    Science.gov (United States)

    Kamal, Ahmed; Nagaseshadri, B; Nayak, V Lakshma; Srinivasulu, Vunnam; Sathish, Manda; Kapure, Jeevak Sopanrao; Suresh Reddy, C

    2015-12-01

    A series of benzimidazole-oxindole conjugates were synthesized and evaluated for their cytotoxic activity. The cytotoxicity assay results suggest that conjugates 5c and 5p exhibit promising cytotoxicity against human breast cancer cell line (MCF-7). The Cell cycle analysis revealed that these conjugates induced cell cycle arrest at G2/M phase in MCF-7 cells. The tubulin polymerization assay results suggested that these conjugates inhibit tubulin polymerization with IC50 values 1.12 and 1.59μM respectively. Immunofluorescence analysis also suggested that these conjugates effectively inhibited the microtubule assembly in MCF-7 cells. Further, molecular docking studies indicated that these conjugates 5c and 5p interact and binds efficiently with the tubulin protein. By and large, the results demonstrated that these benzimidazole-oxindole conjugates possess cytotoxic property by inhibiting the tubulin polymerization.

  15. Trastuzumab labeled to high specific activity with ¹¹¹In by conjugation to G4 PAMAM dendrimers derivatized with multiple DTPA chelators exhibits increased cytotoxic potency on HER2-positive breast cancer cells.

    Science.gov (United States)

    Chan, Conrad; Cai, Zhongli; Reilly, Raymond M

    2013-08-01

    To conjugate trastuzumab with/without NLS peptides to G4 PAMAM dendrimers derivatized with DTPA and determine the specific radioactivity (SA) for (111)In labeling, HER2 immunoreactivity and cytotoxicity on breast cancer (BC) cells. G4 dendrimers were reacted with DTPA then conjugated through a thiol to maleimide-derivatized trastuzumab. The SA achievable was determined by incubating 2 to 20 μg with 60 MBq of (111)In. HER2 immunoreactivity, internalization and nuclear importation were measured. The effect of (111)In-DTPA-G4-trastuzumab (5.9 MBq/μg) on the clonogenic survival (CS) of SK-Br-3 or MDA-MB-231 cells with high or low HER2 density, respectively was compared to (111)In-DTPA-NLS-trastuzumab (0.5 MBq/μg). DNA double-strand breaks (DSBs) were measured. DTPA-G4-trastuzumab was labeled with (111)In to a SA (23.6 MBq/μg) which was 100-fold higher than (111)In-DTPA-NLS-trastuzumab. (111)In-DTPA-G4-trastuzumab and (111)In-DTPA-G4-NLS-trastuzumab retained HER2 immunoreactivity and were internalized and imported into the nucleus of BC cells. G4-radioimmunoconjugates were 2-4 fold and 9-fold more cytotoxic to SK-Br-3 and MDA-MB-231 cells, respectively than (111)In-DTPA-NLS-trastuzumab which was associated with an increase in DNA DSBs. Conjugation of trastuzumab to G4 PAMAM dendrimers modified with 30 DTPA permitted high SA (111)In labeling which increased their cytotoxic potency for BC cells with high or low HER2 density.

  16. Functionalized conjugated polyelectrolytes design and biomedical applications

    CERN Document Server

    Wang, Shu

    2014-01-01

    Functionalized Conjugated Polyelectrolytes presents a comprehensive review of these polyelectrolytes and their biomedical applications. Basic aspects like molecular design and optoelectronic properties are covered in the first chapter. Emphasis is placed on the various applications including sensing (chemical and biological), disease diagnosis, cell imaging, drug/gene delivery and disease treatment. This book explores a multi-disciplinary topic of interest to researchers working in the fields of chemistry, materials, biology and medicine. It also offers an integrated perspective on both basic research and application issues. Functionalized conjugated polyelectrolyte materials, which have already drawn considerable interest, will become a major new direction for biomedicine development.

  17. Sources and Bioactive Properties of Conjugated Dietary Fatty Acids.

    Science.gov (United States)

    Hennessy, Alan A; Ross, Paul R; Fitzgerald, Gerald F; Stanton, Catherine

    2016-04-01

    The group of conjugated fatty acids known as conjugated linoleic acid (CLA) isomers have been extensively studied with regard to their bioactive potential in treating some of the most prominent human health malignancies. However, CLA isomers are not the only group of potentially bioactive conjugated fatty acids currently undergoing study. In this regard, isomers of conjugated α-linolenic acid, conjugated nonadecadienoic acid and conjugated eicosapentaenoic acid, to name but a few, have undergone experimental assessment. These studies have indicated many of these conjugated fatty acid isomers commonly possess anti-carcinogenic, anti-adipogenic, anti-inflammatory and immune modulating properties, a number of which will be discussed in this review. The mechanisms through which these bioactivities are mediated have not yet been fully elucidated. However, existing evidence indicates that these fatty acids may play a role in modulating the expression of several oncogenes, cell cycle regulators, and genes associated with energy metabolism. Despite such bioactive potential, interest in these conjugated fatty acids has remained low relative to the CLA isomers. This may be partly attributed to the relatively recent emergence of these fatty acids as bioactives, but also due to a lack of awareness regarding sources from which they can be produced. In this review, we will also highlight the common sources of these conjugated fatty acids, including plants, algae, microbes and chemosynthesis.

  18. Synthesis and Cytotoxicity of Derivatives of Fluorouracil Conjugated with Three-membered Ring

    Institute of Scientific and Technical Information of China (English)

    WANG, Le; ZHANG, Yunxiao; TAO, Jingchao

    2009-01-01

    A novel series of 3-membered ring fluorouracil conjugates including cyclopropylmethyl fluorouracil and (2,3- epoxypropyl) fluorouracil conjugates were synthesized via selective protection, and their structures were confirmed by IR, 1H NMR and HRMS. Cytotoxicities in vitro of these conjugates were evaluated. Compounds 7, 8, 12 and 13 have shown cytotoxicities against Ec9706 cells in different degrees.

  19. A Novel Polysaccharide Conjugate from Bullacta exarata Induces G1-Phase Arrest and Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells

    Directory of Open Access Journals (Sweden)

    Ningbo Liao

    2017-03-01

    Full Text Available Bullacta exarata has been consumed in Asia, not only as a part of the normal diet, but also as a traditional Chinese medicine with liver- and kidney-benefitting functions. Several scientific investigations involving extraction of biomolecules from this mollusk and pharmacological studies on their biological activities have been carried out. However, little is known regarding the antitumor properties of polysaccharides from B. exarata, hence the polysaccharides from B. exarata have been investigated here. One polysaccharide conjugate BEPS-IA was isolated and purified from B. exarata. It mainly consisted of mannose and glucose in a molar ratio of 1:2, with an average molecular weight of 127 kDa. Thirteen general amino acids were identified to be components of the protein-bound polysaccharide. Methylation and NMR studies revealed that BEPS-IA is a heteropolysaccharide consisting of 1,4-linked-α-d-Glc, 1,6-linked-α-d-Man, 1,3,6-linked-α-d-Man, and 1-linked-α-d-Man residue, in a molar ratio of 6:1:1:1. In order to test the antitumor activity of BEPS-IA, we investigated its effect against the growth of human hepatocellular carcinoma cells HepG2 in vitro. The result showed that BEPS-IA dose-dependently exhibited an effective HepG2 cells growth inhibition with an IC50 of 112.4 μg/mL. Flow cytometry analysis showed that BEPS-IA increased the populations of both apoptotic sub-G1 and G1 phase. The result obtained from TUNEL assay corroborated apoptosis which was shown in flow cytometry. Western blot analysis suggested that BEPS-IA induced apoptosis and growth inhibition were associated with up-regulation of p53, p21 and Bax, down-regulation of Bcl-2. These findings suggest that BEPS-IA may serve as a potential novel dietary agent for hepatocellular carcinoma.

  20. Optical imaging of head and neck squamous cell carcinoma in vivo using arginine-glycine- aspartic acid peptide conjugated near-infrared quantum dots

    Directory of Open Access Journals (Sweden)

    Huang H

    2013-12-01

    Full Text Available Hao Huang, Yun-Long Bai, Kai Yang, Hong Tang, You-Wei WangDepartment of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of ChinaAbstract: Molecular imaging plays a key role in personalized medicine and tumor diagnosis. Quantum dots with near-infrared emission spectra demonstrate excellent tissue penetration and photostability, and have recently emerged as important tools for in vivo tumor imaging. Integrin αvβ3 has been shown to be highly and specifically expressed in endothelial cells of tumor angiogenic vessels in almost all types of tumors, and specifically binds to the peptide containing arginine-glycine-aspartic acid (RGD. In this study, we conjugated RGD with quantum dots with emission wavelength of 800 nm (QD800 to generate QD800-RGD, and used it via intravenous injection as a probe to image tumors in nude mice bearing head and neck squamous cell carcinoma (HNSCC. Twelve hours after the injection, the mice were still alive and were sacrificed to isolate tumors and ten major organs for ex vivo analysis to localize the probe in these tissues. The results showed that QD800-RGD was specifically targeted to integrin αvβ3 in vitro and in vivo, producing clear tumor fluorescence images after the intravenous injection. The tumor-to-background ratio and size of tumor image were highest within 6 hours of the injection and declined significantly at 9 hours after the injection, but there was still a clearly visible tumor image at 12 hours. The greatest amount of QD800-RGD was found in liver and spleen, followed by tumor and lung, and a weak fluorescence signal was seen in tibia. No detectable signal of QD800-RGD was found in brain, heart, kidney, testis, stomach, or intestine. Our study demonstrated that using integrin αvβ3 as target, it is possible to use intravenously injected QD800-RGD to generate high quality images of HNSCC, and the technique offers great potential

  1. The first dose of a Haemophilus influenzae type b conjugate vaccine reactivates memory B cells: evidence for extensive clonal selection, intraclonal affinity maturation, and multiple isotype switches to IgA2

    DEFF Research Database (Denmark)

    Hougs, L; Juul, L; Ditzel, H J

    1999-01-01

    The Ab response of a healthy adult to the first dose of a Haemophilus influenzae type b capsular polysaccharide (HibCP) conjugate vaccine was studied at the level of Ig gene usage by circulating Ab-secreting cells. Forty-one IgA and 17 IgG mRNA sequences were obtained. The major part of the respo......The Ab response of a healthy adult to the first dose of a Haemophilus influenzae type b capsular polysaccharide (HibCP) conjugate vaccine was studied at the level of Ig gene usage by circulating Ab-secreting cells. Forty-one IgA and 17 IgG mRNA sequences were obtained. The major part...... selected, and expanded population of cells existing before vaccination, i.e., memory B cells. The dominating heavy and light chains of the response were combined in a Fab that bound HibCP. It was shown that the shared heavy and light chain mutations increased the affinity for HibCP considerably, indicating...... that the clonal selection had been driven by affinity. Pre-existing memory cells in unvaccinated adults may explain several features of Ab responses to polysaccharide vaccines and may play a role in acquiring the ability to respond to pure polysaccharides during infancy....

  2. Chlorambucil gemcitabine conjugate nanomedicine for cancer therapy.

    Science.gov (United States)

    Fan, Mingliang; Liang, Xiaofei; Li, Zonghai; Wang, Hongyang; Yang, Danbo; Shi, Bizhi

    2015-11-15

    Self-assembly of anticancer small molecules into nanostructures may represent an attractive approach to improve the treatment of experimental solid tumors. As a proof of concept, we designed and synthesized the conjugate prodrug of hydrophilic gemcitabine by its covalent coupling to hydrophobic chlorambucil via a hydrolyzable ester linkage. The resulting amphiphilic conjugates self-assembled into nanoparticles in water and exhibited significant anticancer activity in vitro against a variety of human cancer cells. In vivo anticancer activity of these nanoparticles has been tested on subcutaneous grafted SMMC-7721 hepatocellular carcinoma model. Such chlorambucil gemcitabine conjugate nanomedicine should have potential applications in cancer therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Tight-binding treatment of conjugated polymers

    DEFF Research Database (Denmark)

    Lynge, Thomas Bastholm

    This PhD thesis concerns conjugated polymers which constitute a constantly growing research area. Today, among other things, conjugated polymers play a role in plastic based solar cells, photodetectors and light emitting diodes, and even today such plastic-based components constitute an alternative...... of tomorrow. This thesis specifically treats the three conjugated polymers trans-polyacetylene (tPA), poly(para-phenylene) (PPP) and poly(para-phe\\-nylene vinylene) (PPV). The present results, which are derived within the tight-binding model, are divided into two parts. In one part, analytic results...... are derived for the optical properties of the polymers expressed in terms of the optical susceptibility both in the presence and in the absence of a static electric field. In the other part, the cumputationally efficient Density Functional-based Tight-Binding (DFTB) model is applied to the description...

  4. Synthesis and Antiproliferative Activity of Silybin Conjugates with Salinomycin and Monensin.

    Science.gov (United States)

    Antoszczak, Michał; Klejborowska, Greta; Kruszyk, Monika; Maj, Ewa; Wietrzyk, Joanna; Huczyński, Adam

    2015-12-01

    Aiming at development of multitarget drugs for the anticancer treatment, new silybin (SIL) conjugates with salinomycin (SAL) and monensin (MON) were synthesized, in mild esterification conditions, and their antiproliferative activity was studied. The conjugates obtained exhibit anticancer activity against HepG2, LoVo and LoVo/DX cancer cell lines. Moreover, MON-SIL conjugate exhibits higher anticancer potential and better selectivity than the corresponding SAL-SIL conjugate.

  5. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  6. Comparison of metabolism-mediated effects of pyrrolizidine alkaloids in a HepG2/C3A cell-S9 co-incubation system and quantification of their glutathione conjugates.

    Science.gov (United States)

    Tamta, Hemlata; Pawar, Rahul S; Wamer, Wayne G; Grundel, Erich; Krynitsky, Alexander J; Rader, Jeanne I

    2012-10-01

    1. Toxicity of pyrrolizidine alkaloids (PAs) largely depends on their metabolic activation by hepatic enzymes, including cytochrome P450s, to become chemically reactive pyrrolic derivatives. These then spontaneously release the esterifying acids to generate carbonium ions that form covalent adducts with cellular nucleophiles to exhibit toxicity. 2. In our investigation, metabolism-mediated toxicity of monocrotaline, retrorsine, lycopsamine, echimidine (retronecine-type PAs), heliotrine (a heliotridine-type PA) and senkirkine (an otonecine-type PA) was studied using an in vitro co-incubation assay. 3. Human hepatocarcinoma (HepG2/C3A) cells were incubated with PAs in the presence and absence of rat liver S9 fraction and the toxicity was assessed as lowered mitochondrial activity. 4. Bioactivation potential was measured by incubating PAs with rat liver S9 fraction, NADPH and GSH in a cell free system. Pyrrolic metabolites generated were entrapped as glutathione conjugates (7-GSH-DHP and 7,9-di-GSHDHP) which were quantified using LC-MS-MS analysis. 5. Our results indicated that PAs were metabolized by rat liver S9 fraction into reactive pyrrolic derivatives which were toxic to HepG2/C3A cells. This approach can be used to determine and compare bioactivation potential and metabolism-mediated toxicity of various PAs.

  7. Interaction of a dinuclear fluorescent Cd(II) complex of calix[4]arene conjugate with phosphates and its applicability in cell imaging.

    Science.gov (United States)

    Sreenivasu Mummidivarapu, V V; Hinge, Vijaya Kumar; Rao, Chebrolu Pulla

    2015-01-21

    A triazole-linked hydroxyethylimino conjugate of calix[4]arene () and its cadmium complex have been synthesized and characterized, and their structures have been established. In the complex, both the Cd(2+) centers are bound by an N2O4 core, and one of it is a distorted octahedral, whereas the other is a trigonal anti-prism. The fluorescence intensity of the di-nuclear Cd(ii) complex is quenched only in the presence of phosphates and not with other anions studied owing to their binding affinities and the nature of the interaction of the phosphates with Cd(2+). These are evident even from their absorption spectra. Different phosphates exhibit changes in both their fluorescence as well as absorption spectra to varying extents, suggesting their differential interactions. Among the six phosphates, H2PO4(-) has higher fluorescence quenching even at low equivalents of this ion, whereas P2O7(4-) shows only 50% quenching even at 10 equivalents. The fluorescence quenching is considerable even at 20 ppb (0.2 μM) of H2PO4(-), whereas all other phosphates require a concentration of 50-580 ppb to exhibit the same effect on fluorescence spectra. Thus, the interaction of H2PO4(-) is more effective by ∼30 fold as compared to that of P2O7(4-). Fluorescence quenching by phosphate is due to the release of from its original cadmium complex via the formation of a ternary species followed by the capture of Cd(2+) by the phosphate, as delineated based on the combination of spectral techniques, such as absorption, emission, (1)H NMR and ESI MS. The relative interactive abilities of the six phosphates differ from each other. The removal of Cd(2+) is demonstrated to be reversible by the repeated addition of the phosphate followed by Cd(2+). The characteristics of the ternary species formed in each of these six phosphates have been computationally modeled using molecular mechanics. The computational study revealed that the coordination between cadmium and -CH2-CH2-OH breaks and new

  8. Genetic Drift Suppresses Bacterial Conjugation in Spatially Structured Populations

    Science.gov (United States)

    Freese, Peter D.; Korolev, Kirill S.; Jiménez, José I.; Chen, Irene A.

    2014-02-01

    Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid agar, and we develop a quantitative understanding by spatial extension of traditional mass-action models. We found that spatial structure suppresses conjugation in surface-associated growth because strong genetic drift leads to spatial isolation of donor and recipient cells, restricting conjugation to rare boundaries between donor and recipient strains. These results suggest that ecological strategies, such as enforcement of spatial structure and enhancement of genetic drift, could complement molecular strategies in slowing the spread of antibiotic resistance genes.

  9. Synthesis and in Vitro Cytotoxicity of a Novel Conjugate of Polyamide and Phospholipid

    Institute of Scientific and Technical Information of China (English)

    Yi LIU; Yu Lin DENG; Rong ZHENG; Pei Long ZHANG; Hui ZHAI; Ke Zhong LIU; Chang Jin ZHU

    2006-01-01

    In order to increase the cell penetration and decrease the cytotoxicity of the synthetic molecule, we designed and synthesized a DNA-binding ligand, which was a conjugate of polyamide and phospholipid. We examined the differences in the effect on cytotoxicity between the conjugate and the native polyamide. As expected that the in vitro cytotoxicity of the conjugate was obviously lower than that of the native polyamide either in HeLa cells or SH-SY5Y neuroblastoma cells.

  10. Discrete modelling of bacterial conjugation dynamics

    CERN Document Server

    Goni-Moreno, Angel

    2012-01-01

    In bacterial populations, cells are able to cooperate in order to yield complex collective functionalities. Interest in population-level cellular behaviour is increasing, due to both our expanding knowledge of the underlying biological principles, and the growing range of possible applications for engineered microbial consortia. Researchers in the field of synthetic biology - the application of engineering principles to living systems - have, for example, recently shown how useful decision-making circuits may be distributed across a bacterial population. The ability of cells to interact through small signalling molecules (a mechanism known as it quorum sensing) is the basis for the majority of existing engineered systems. However, horizontal gene transfer (or conjugation) offers the possibility of cells exchanging messages (using DNA) that are much more information-rich. The potential of engineering this conjugation mechanism to suit specific goals will guide future developments in this area. Motivated by a l...

  11. Theory of Digitized Conjugate Surface and Solution to Conjugate Surface

    Institute of Scientific and Technical Information of China (English)

    Xiao Lai-yuan; Liao Dao-xun; Yi Chuan-yun

    2004-01-01

    In order to meet the needs of designing and processing digitized surfaces, the method to spreading digitized surface has been proposed. The key technique is to solve the problem of digitized conjugate surface. In the paper, the digitized conjugate surface was theoretically investigated, and the solution of conjugate surface based on digitized surface was also studied. The digitized conjugate surface theory was then proposed, and applied to build the model of solving conjugate surface based on digitized surface. A corresponding algorithm was developed. This paper applies the software Conjugater-1.0 that is developed by ourselves to compute the digitized conjugate surfaces of the drum-tooth surface. This study provides theoretical and technical bases for analyzing engagement of digitized surface, simulation and numerical processing technique.

  12. HER2 specific delivery of methotrexate by dendrimer conjugated anti-HER2 mAb

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Rameshwer; Thomas, Thommey P; Desai, Ankur M; Kotlyar, Alina; Park, Steve J; Baker, James R Jr [Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, 9220 MSRB III, Box 0648, Ann Arbor, MI 48109 (United States)], E-mail: rameshwe@umich.edu, E-mail: jbakerjr@med.umich.edu

    2008-07-23

    Herceptin, a humanized monoclonal antibody that binds to human growth factor receptor-2 (HER2), was covalently attached to a fifth-generation (G5) polyamidoamine dendrimer containing the cytotoxic drug methotrexate. The specific binding and internalization of this conjugate labeled with FITC was clearly demonstrated in cell lines overexpressing HER2 by flow cytometry as well as confocal microscopic analysis. In addition, binding and uptake of antibody conjugated dendrimers was completely blocked by excess non-conjugated herceptin. The dendrimer conjugate was also shown to inhibit the dihydrofolate reductase with similar activity to methotrexate. Co-localization experiments with lysotracker red indicate that antibody conjugate, although internalized efficiently into cells, has an unusually long residence time in the lysosome. Somewhat lower cytotoxicity of the conjugate in comparison to free methotrexate was attributed to the slow release of methotrexate from the conjugate and its long retention in the lysosomal pocket.

  13. Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis.

    Science.gov (United States)

    Topuzogullari, Murat; Cakir Koc, Rabia; Dincer Isoglu, Sevil; Bagirova, Melahat; Akdeste, Zeynep; Elcicek, Serhat; Oztel, Olga N; Yesilkir Baydar, Serap; Canim Ates, Sezen; Allahverdiyev, Adil M

    2013-06-03

    Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential.

  14. Multicellular computing using conjugation for wiring.

    Science.gov (United States)

    Goñi-Moreno, Angel; Amos, Martyn; de la Cruz, Fernando

    2013-01-01

    Recent efforts in synthetic biology have focussed on the implementation of logical functions within living cells. One aim is to facilitate both internal "re-programming" and external control of cells, with potential applications in a wide range of domains. However, fundamental limitations on the degree to which single cells may be re-engineered have led to a growth of interest in multicellular systems, in which a "computation" is distributed over a number of different cell types, in a manner analogous to modern computer networks. Within this model, individual cell type perform specific sub-tasks, the results of which are then communicated to other cell types for further processing. The manner in which outputs are communicated is therefore of great significance to the overall success of such a scheme. Previous experiments in distributed cellular computation have used global communication schemes, such as quorum sensing (QS), to implement the "wiring" between cell types. While useful, this method lacks specificity, and limits the amount of information that may be transferred at any one time. We propose an alternative scheme, based on specific cell-cell conjugation. This mechanism allows for the direct transfer of genetic information between bacteria, via circular DNA strands known as plasmids. We design a multi-cellular population that is able to compute, in a distributed fashion, a Boolean XOR function. Through this, we describe a general scheme for distributed logic that works by mixing different strains in a single population; this constitutes an important advantage of our novel approach. Importantly, the amount of genetic information exchanged through conjugation is significantly higher than the amount possible through QS-based communication. We provide full computational modelling and simulation results, using deterministic, stochastic and spatially-explicit methods. These simulations explore the behaviour of one possible conjugation-wired cellular computing

  15. Expression of the Saccharomyces cerevisiae DNA repair gene RAD6 that encodes a ubiquitin conjugating enzyme, increases in response to DNA damage and in meiosis but remains constant during the mitotic cell cycle.

    Science.gov (United States)

    Madura, K; Prakash, S; Prakash, L

    1990-02-25

    The RAD6 gene of Saccharomyces cerevisiae encodes a ubiquitin-conjugating (E2) enzyme and is required for the repair of damaged DNA, mutagenesis, and sporulation. Here, we report our studies on the regulation of RAD6 gene expression after UV damage, during the mitotic cell cycle, in meiosis, and following heat shock and starvation. RAD6 mRNA levels became elevated in cells exposed to UV light, and at all UV doses the increase in mRNA levels was rapid and occurred within 30 min after exposure to UV. RAD6 mRNA levels also increased in sporulating MATa/MAT alpha cells, and the period of maximal accumulation of RAD6 mRNA during meiosis is coincident with the time during which recombination occurs. However, RAD6 mRNA levels showed no periodic fluctuation in the mitotic cell cycle, were not elevated upon heat shock, and fell in cells in the stationary phase of growth. These observations suggest that RAD6 activity is required throughout the cell cycle rather than being restricted to a specific stage, and that during meiosis, high levels of RAD6 activity may be needed at a stage coincident with genetic recombination. The observation that RAD6 transcription is not induced by heat and starvation, treatments that activate stress responses, suggests that the primary role of RAD6 is in the repair of damaged DNA rather than in adapting cells to stress situations.

  16. Synthesis of arylpyrazole linked benzimidazole conjugates as potential microtubule disruptors.

    Science.gov (United States)

    Kamal, Ahmed; Shaik, Anver Basha; Polepalli, Sowjanya; Kumar, G Bharath; Reddy, Vangala Santhosh; Mahesh, Rasala; Garimella, Srujana; Jain, Nishant

    2015-03-01

    In an attempt to develop potent and selective anticancer agents, a series of twenty arylpyrazole linked benzimidazole conjugates (10a-t) were designed and synthesized as microtubule destabilizing agents. The joining of arylpyrazole to the benzimidazole moiety resulted in a four ring (A, B, C and D) molecular scaffold that comprises of polar heterocyclic rings in the middle associated with rotatable single bonds and substituted aryl rings placed in the opposite directions. These conjugates were evaluated for their ability to inhibit the growth of sixty cancer cell line panel of the NCI. Among these some conjugates like 10a, 10b, 10d, 10e, 10p and 10r exhibited significant growth inhibitory activity against most of the cell lines ranging from 0.3 to 13μM. Interestingly, the conjugate 10b with methoxy group on D-ring expressed appreciable cytotoxic potential. A549 cells treated with some of the potent conjugates like 10a, 10b and 10d arrested cells at G2/M phase apart from activating cyclin-B1 protein levels and disrupting microtubule network. Moreover, these conjugates effectively inhibited tubulin polymerization with IC50 values of 1.3-3.8μM. Whereas, the caspase assay revealed that they activate the casepase-3 leading to apoptosis. Particularly 10b having methoxy substituent induced activity almost 3 folds higher than CA-4. Furthermore, a competitive colchicine binding assay and molecular modeling analysis suggests that these conjugates bind to the tubulin successfully at the colchicine binding site. These investigations reveal that such conjugates having pyrazole and benzimidazole moieties have the potential in the development of newer chemotherapeutic agents.

  17. Polymer decorated gold nanoparticles in nanomedicine conjugates.

    Science.gov (United States)

    Capek, Ignác

    2017-02-15

    Noble metal, especially gold nanoparticles and their conjugates with biopolymers have immense potential for disease diagnosis and therapy on account of their surface plasmon resonance (SPR) enhanced light scattering and absorption. Conjugation of noble metal nanoparticles to ligands specifically targeted to biomarkers on diseased cells allows molecular-specific imaging and detection of disease. The development of smart gold nanoparticles (AuNPs) that can deliver therapeutics at a sustained rate directly to cancer cells may provide better efficacy and lower toxicity for treating cancer tumors. We highlight some of the promising classes of targeting systems that are under development for the delivery of gold nanoparticles. Nanoparticles designed for biomedical applications are often coated with polymers containing reactive functional groups to conjugate targeting ligands, cell receptors or drugs. Using targeted nanoparticles to deliver chemotherapeutic agents in cancer therapy offers many advantages to improve drug/gene delivery and to overcome many problems associated with conventional radiotherapy and chemotherapy. The targeted nanoparticles were found to be effective in killing cancer cells which were studied using various anticancer assays. Cell morphological analysis shows the changes occurred in cancer cells during the treatment with AuNPs. The results determine the influence of particle size and concentration of AuNPs on their absorption, accumulation, and cytotoxicity in model normal and cancer cells. As the mean particle diameter of the AuNPs decreased, their rate of absorption by the intestinal epithelium cells increased. These results provide important insights into the relationship between the dimensions of AuNPs and their gastrointestinal uptake and potential cytotoxicity. Furthermore gold nanoparticles efficiently convert the absorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. We also review

  18. In Vivo Study of Ligament-Bone Healing after Anterior Cruciate Ligament Reconstruction Using Autologous Tendons with Mesenchymal Stem Cells Affinity Peptide Conjugated Electrospun Nanofibrous Scaffold

    Directory of Open Access Journals (Sweden)

    Jingxian Zhu

    2013-01-01

    Full Text Available Electrospinning nanofibrous scaffold was commonly used in tissue regeneration recently. Nanofibers with specific topological characteristics were reported to be able to induce osteogenic differentiation of MSCs. In this in vivo study, autologous tendon grafts with lattice-like nanofibrous scaffold wrapping at two ends of autologous tendon were used to promote early stage of ligament-bone healing after rabbit ACL reconstruction. To utilize native MSCs from bone marrow, an MSCs specific affinity peptide E7 was conjugated to nanofibrous meshes. After 3 months, H-E assessment and specific staining of collagen type I, II, and III showed direct ligament-bone insertion with typical four zones (bone, calcified fibrocartilage, fibrocartilage, and ligament in bioactive scaffold reconstruction group. Diameters of bone tunnel were smaller in nanofibrous scaffold conjugated E7 peptide group than those in control group. The failure load of substitution complex also indicated a stronger ligament-bone insertion healing using bioactive scaffold. In conclusion, lattice-like nanofibrous scaffold with specific MSCs affinity peptide has great potential in promoting early stage of ligament-bone healing after ACL reconstruction.