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Синтез и исследования карбоксилановых дендримеров

Журнальные статьи

Abkenar, Samera Salimpour; Malek, Reza Mohammad Ali Preparation, characterization, and antimicrobial property of cotton cellulose fabric grafted with poly (propylene imine) dendrimer // CELLULOSE. 2012. Т. 19. №5. С. 1701-1714.

Two generations of poly (propylene imine) dendrimer with amino terminated groups (G2- and G5-PPI-NH2) were grafted on cotton cellulose fabric using cross linking agents (citric or glutaric acids). Fourier transform infrared (FTIR) spectroscopy identified ester groups which were formed between hydroxyl groups of the cotton fabric and carboxylic groups of the cross linking agents. Also, attenuated total reflectance-FTIR (ATR-FTIR) analysis confirmed formation of amide groups between the carboxylic groups of the cross linking agents and the amino end groups of the dendrimers. Nitrogen content (N-content) analysis revealed the presence of the dendrimers on the cotton fabric even after 5 washing cycles. In order to study the dispersion of the PPI dendrimers on the surface of the cotton fabric, field emission scanning electron microscopy (FE-SEM) was performed. The particle size distribution of the G2- and G5-PPI-NH2 aqueous solutions was also determined by dynamic light scattering (DLS) analysis. Antimicrobial activity of the PPI dendrimer aqueous solutions and the cotton cellulose fabric grafted with the dendrimers was evaluated both quantitatively and qualitatively against Gram-positive bacterium (Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and fungus (Candida albicans). The dendrimer grafted cotton cellulose fabric exhibited a 99 % reduction in bacterial counts against S. aureus, E. coli and C. albicans. The antimicrobial activities of the grafted cotton cellulose fabric with the PPI dendrimers were maintained even after 5 washing cycles.

Algarra, M.; Campos, B. B.; Miranda, M. S.; et al.Cd Se quantum dots capped PAMAM dendrimer nanocomposites for sensing nitroaromatic compounds //TALANTA. 2011. Т. 83. №5. С. 1335-1340.

The detection of nitroaromatic compounds, best known as raw materials in explosives preparations, is important in many fields including environmental science, public security and forensics. CdSe quantum dots capped with PAMAM-G(4) dendrimer were synthetized in water and used for the detection of trace amounts of three nitroaromatic compounds: 4-methoxy-2-nitrophenol (MNP), 2-amine-5chloro-1,3-dinitrobenzene (ACNB) and 3-methoxy-4-nitrobenzoic acid (MNB). To increase the apparent water solubility of these compounds alpha-cyclodextrin (alpha-CD) was used to promote the formation of inclusion complexes. The studied nitroaromatic compounds (plus alpha-CD) significantly quenched the fluorescence intensity of the nanocomposite with linear Stern-Volmer plots. The Stern-Volmer constants (standard deviation in parenthesis) were: MNB, K(SV) = 65(5) x 10(4) M(-1); ACNB, K(SV) = 19(2) x 10(4) M(-1); and, MNP, K(SV) =33(1) x 10(2) M(-1). These constants suggest the formation of a ground state complex between the nitroaromatric compounds and the sensor which confers a relatively high analytical sensitivity. The detection sensibilities are about 0.01 mg L(-1) for MNB and ACNB and about 0.1 mg L(-1) for MNP. No interferences or small interferences are observed for trinitrotoluene [K(SV) =10(2) x 10(2) x M(-1)], 2,4-dinitrotoluene [K(SV) = 20(3) x 10 M(-1)], 2,6-dinitrotoluene [K(SV) = 11(4) x 10 M(-1)] and nitrobenzene [K(SV) = 2(1) x 10(3) x M(-1)]. (C) 2010 Elsevier B.V. All rights reserved.

Bernechea, Maria; Garcia-Rodriguez, Sergio; Terreros, Pilar; et al. Synthesis of Core-Shell PtRu Dendrimer-Encapsulated Nanoparticles. Relevance as Electrocatalysts for CO Oxidation // JOURNAL OF PHYSICAL CHEMISTRY C. 2011. Т. 115. №4. С. 1287-1294.

Synthesis of PtRu nanoparticles has been accomplished by using the dendrimer-encapsulated nanoparticle (DEN) approach. We report that the surface distribution of the particles can be tuned by suitable control of the reaction pathway. The present study focuses on the synthesis and characterization of Pt and PtRu nanoparticles and the evaluation of their performance as CO(ad) electro-oxidation catalysts. Bimetallic Pt/Ru particles displaying Ru-core Pt-shell (Ru@Pt) and Pt-core Ru-shell (Pt@Ru) structures, in which Ru or Pt are preferentially located on the outermost layer of the nanoparticles, have been synthesized. Characterization data confirm the formation of the bimetallic particles with the desired atomic distribution. The importance of the actual nature of the bimetallic samples in the CO(ad) electro-oxidation reaction has been discussed.

Boateng, Jonas; Peek, Joel; Zahorchak, Robert; et al. Dendron-modified surfaces provide an ideal environment for stem-loop DNA probes//ANALYTICAL BIOCHEMISTRY. 2012. Т. 430. №1. С. 39-44.

Specificity and sensitivity are important factors affecting DNA microarrays. Stem-loop DNA probes (SLPs) can be more specific in their recognition of target sequences than linear DNA probes, but unless they are carefully designed, surface interactions can disrupt the native stem-loop structure. In this study, we show how dendron-modified surfaces with well-defined, uniform spacing of aldehyde chemical functionalities offer an ideal substrate to immobilize SLPs and use them to detect nucleic acid targets. The mesospacing provided by the dendron-modified surfaces produces a solution-like environment that allows the SLPs to detect target nucleic acids at concentrations as low as 1 pM in concentration.

Cardoso, F. P.; Aquino Neto, S.; Fenga, P. G.; et al. Electrochemical characterization of methanol/O-2 biofuel cell: Use of laccase biocathode immobilized with polypyrrole film and PAMAM dendrimers //ELECTROCHIMICA ACTA. 2013. Т. 90. №-. С. 90-94.


Chang, Yulei; Meng, Xinlei; Zhao, Yili; et al. Novel water-soluble and pH-responsive anticancer drug nanocarriers: Doxorubicin-PAMAM dendrimer conjugates attached to superparamagnetic iron oxide nanoparticles (IONPs) //JOURNAL OF COLLOID AND INTERFACE SCIENCE. 2011. Т. 363. №1. С. 403-409.

PH-responsive drug release system based on the conjugates of PAMAM dendrimers-doxorubicin (PAMAM-DOX) and superparamagnetic iron oxide (Fe(3)O(4)) nanoparticles (IONPs) has been constructed and characterized. The IONPs were stabilized by mPEG-G2.5 PAMAM dendrimers. The anticancer drug DOX was conjugated to the dendrimer segments of amino-stabilized IONPs using hydrazine as the linker via hydrazone bonds, which is acid cleavable and can be used as an ideal pH-responsive drug release system. The drug release profiles of DOX-PAMAM dendrimer conjugates were studied at pH 5.0 and 7.4. The results showed that the hydrolytic release profile can be obtained only at the condition of lysosomal pH (pH = 5.0), and IONPs participated in carrying DOX to the tumor by the Enhanced Permeability and Retention (EPR) effect. These novel DOX-conjugated IONPs have the potential to enhance the effect of MRI contrast and cancer therapy in the course of delivering anticancer drugs to their target sites. Although the dendrimer-DOX-coated IONPs do not have any targeting ligands attached on their surface, they are potentially useful for cancer diagnosis in vivo. (C) 2011 Elsevier Inc. All rights reserved.

Cheng Z., Thorek D.L.J., Tsourkas A. GADOLINIUM-CONJUGATED DENDRIMER NANOCLUSTERS AS A TUMOR-TARGETED T 1 MAGNETIC RESONANCE IMAGING CONTRAST AGENT//Angewandte Chemie - International Edition. 2010. Т. 49. № 2. С. 346-350.

"Chemical Equation Presented" Light heavyweight champion: Chemically cross-linked dendrimer nanoclusters (DNCs) have been developed as a platform for preparing targeted magnetic resonance contrast agents. The extremely high gadolinium payload causes the DNCs to show a significant improvement in tumor contrast compared with pre-contrast images (see picture).

Ciolkowski, Michal; Rozanek, Monika; Szewczyk, Michal; et al. The influence of PAMAM-OH dendrimers on the activity of human erythrocytes ATPases//BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES. 2011. Т. 1808. №11. С. 2714-2723.

Dendrimers are a relatively new and still not fully examined group of polybranched polymers. In this study polyamidoamine dendrimers with hydroxyl surface groups (PAMAM-OH) of third, fourth and fifth generation (G3, G4 and G5) were examined for their ability to influence the activity of human erythrocyte plasma membrane adenosinetriphosphatases (ATPases). Plasma membrane ATPases are a group of enzymes related, among others, to the maintenance of ionic balance inside the cell. An inhibition of their activity may result in a disturbance of cell functioning. Two of examined dendrimers (G4 and G5) were found to inhibit the activity of Na(+)/K(+) ATPase and Ca(2+) ATPase by 20-30%. The observed effect was diminished when higher concentrations of dendrimers were used. The experiment with the use of pyrene as fluorescent probe sensitive to the changes in microenvironment's polarity revealed that it was an effect of dendrimers' self-aggregation. Additional studies showed that PAMAM-OH dendrimers were able to decrease the fluidity of human erythrocytes plasma membrane. Obtained results suggest that change in plasma membrane fluidity was not caused by the dendrimer-lipid interaction, but dendrimer-protein interaction. Different pattern of influence of dendrimers on ATPases activity and erythrocyte membrane fluidity suggests that observed change in ATPases activity is not a result of dendrimer-lipid interaction, but may be related to direct interaction between dendrimers and ATPases.

Dang, Gaofei; Shi, Yan; Fu, Zhifeng Polymer particles with dendrimer@SiO2-Ag hierarchical shell and their application in catalytic column //JOURNAL OF COLLOID AND INTERFACE SCIENCE. 2012. Т. 369. №-. С. 170-178.

Polymer particles with dendrimer@SiO2-Ag hierarchical shell were prepared, and their application in the catalytic column for the reduction of 4-nitrophenol (4-NP) was also investigated. The PS microspheres with the carboxyl group were used as the supports for the immobilization of dendrimer@SiO2-Ag shell. The polyamidoamine (PAMAM) dendrimer was grafted on the surface of PS microsphere through repetitive Michael addition reaction of methyl acrylate (MA) and amidation of the obtained esters with a large excess of ethylenediamine (EDA) successively. The silver nanoparticles formed inside the PAMAM shell. Then, the silver nanoparticles, which were used as center of nucleation, were coated with SiO2 shell through improved Stober method. Moreover, the more silver nanoparticles were dispersed on the surface of SiO2 shell. The contents of silver element were measured using inductively coupled plasma (ICP-MS). The obtained PS@PAMAM@SiO2-Ag nanoparticles were packed in stainless steel column, which has been used effectively for the catalytic reduction of 4-NP. Under column pressures, the rigid SiO2 shell plays a better role in immobilization of silver nanoparticles than the soft PAMAM shell. This technique for packing catalytic nanoparticles in column improves the efficiency of application with metal catalysts as well as reduces the tedious separation processes in catalytic reaction. (C) 2011 Elsevier Inc. All rights reserved.

Dietrich, Sascha; Chandra, Sudeshna; Georgi, Colin; et Design, characterization and magnetic properties of Fe3O4-nanoparticle arrays coated with PEGylated-dendrimers // MATERIALS CHEMISTRY AND PHYSICS. 2012. Т. 132. №2. С. 292-299.

Drzewinska, Joanna; Appelhans, Dietmar; Voit, Brigitte; et al. Poly(propylene imine) dendrimers modified with maltose or maltotriose protect phosphorothioate oligodeoxynucleotides against nuclease activity//BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. 2012. Т. 427. №1. С.197-201.

The antisense oligonucleotides are promising agents for application in anti-HIV therapies. The antiretroviral nucleoside analogues administrated into circulatory system are vulnerable to nuclease degradation and require a vehicle which would not only facilitate therapeutic nucleotides into host cells, but would also provide protection against enzymatic degradation. Such potential is exhibited by poly(propylene imine) dendrimers - the branched cationic polymers easily interacting with oligonucleotides to form complexes called "dendriplexes". The aim of the present study was to evaluate the abilities of the fourth generation poly(propylene imine) dendrimers partially modified with maltose (PPI-Mal G4) or maltotriose (PPI-Mal-III G4) to protect anti-HIV antisense oligonucleotides (ODNs) from nucleolytic degradation. The ODNs (AT, GEM91, SREV) were complexed with dendrimers and subjected to cleavage by serum nucleases or endonuclease Si. The results showed that all examined dendrimers protected ODNs against nucleases contained in FBS. Both PPI-Mal G4 and PPI-Mal-III G4 dendrimers completely prevented ODNs digestion by nuclease Si at neutral pH. The protective capabilities of investigated dendrimers were significantly weaker in acidic environment. The time stability assay showed that the dendriplexes formed by AT, GEM91, SREV and carbohydrate-modified PPI G4 dendrimers still existed after 12 h incubation both in low and at neutral pH buffers. The conformational change of dendriplexes in acidic environment was proposed as possible phenomenon leading to exposition of ODNs to nuclease attack and significantly diminishing dendriplexes' resistance to nucleolitic digestion.

Dumitrescu, Ioana; Crooks, Richard M. E fect of mass transfer on the oxygen reduction reaction catalyzed by platinum dendrimer encapsulated nanoparticles //PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. 2012. Т. 109. №29. С. 11493-11497.

Here we report on the effect of the mass transfer rate (k(t)) on the oxygen reduction reaction (ORR) catalyzed by Pt dendrimer-encapsulated nanoparticles (DENs) comprised of 147 and 55 atoms (Pt-147 and Pt-55). The experiments were carried out using a dual-electrode microelectrochemical device, which enables the study of the ORR under high k(t) conditions with simultaneous detection of H2O2. At low k(t) (0.02 to 0.12 cm s(-1)) the effective number of electrons involved in ORR, n(eff), is 3.7 for Pt-147 and 3.4 for Pt-55. As k(t) is increased, the mass-transfer-limited current for the ORR becomes significantly lower than the value predicted by the Levich equation for a 4-electron process regardless of catalyst size. However, the percentage of H2O2 detected remains constant, such that n(eff) barely changes over the entire k(t) range explored (0.02 cm s(-1)). This suggests that mass transfer does not affect n(eff), which has implications for the mechanism of the ORR on Pt nanoparticles. Interestingly, there is a significant difference in n(eff) for the two sizes of Pt DENs (n(eff) 3.7 and 3.5 for Pt-147 and Pt-55, respectively) that cannot be assigned to mass transfer effects and that we therefore attribute to a particle size effect.

Franckevicius, M.; Vaisnoras, R.; Marcos, M.; et al. Tautomeric forms of PPI dendrimers functionalized with 4-(4 '-ethoxybenzoyloxy)salicylaldehyde chromophores //CHEMICAL PHYSICS. 2012. Т. 404. №-. С. 2-8.

Bonding of the promesogenic unit derived from 4-(4'-ethoxybenzoyloxy)salicylaldehyde to the amino terminated PPI dendrimer chains results in formation of the salicylidenimine chromophore groups. Absorption and fluorescence investigations of the dendrimer solutions supported by the quantum chemistry calculations revealed that the chromophore groups may exist in enol and keto tautomeric forms with relative concentrations depending on the dendrimer generation and solvent. The dendrimer fluorescence is attributed to n pi* states of keto tautomers which may also be formed from excited enol tautomers. (C) 2012 Elsevier B.V. All rights reserved.

Giannetto, Marco; Umilta, Eleonora; Careri, Maria New competitive dendrimer-based and highly selective immunosensor for determination of atrazine in environmental, feed and food samples: The importance of antibody selectivity for discrimination among related triazinic metabolites//ANALYTICA CHIMICA ACTA. 2010. Т.806. №-. С. 197-203.

A new voltammetric competitive immunosensor selective for atrazine, based on the immobilization of a conjugate atrazine-bovine serum albumine on a nanostructured gold substrate previously functionalized with poliamidoaminic dendrimers, was realized, characterized, and validated in different real samples of environmental and food concern. Response of the sensor was reliable, highly selective and suitable for the detection and quantification of atrazine at trace levels in complex matrices such as territorial waters, corn-cultivated soils, corn-containing poultry and bovine feeds and corn flakes for human use. Selectivity studies were focused on desethylatrazine, the principal metabolite generated by long-term microbiological degradation of atrazine, terbutylazine-2-hydroxy and simazine as potential interferents. The response of the developed immunosensor for atrazine was explored over the 10(-2)-10(3) ng mL(-1) range. Good sensitivity was proved, as limit of detection and limit of quantitation of 1.2 and 5 ng mL(-1), respectively, were estimated for atrazine. RSD values <5% over the entire explored range attested a good precision of the device.

Hart-Smith, Gene A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry//ANALYTICA CHIMICA ACTA. 2014. Т. 808. №-. С. 44-55.

Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community. (C) 2013 Elsevier B. V. All rights reserved.

Hatakeyama, Tomomitsu; Karino, Ryota; Terai, Yasuaki; et al. An Assay for Carbohydrate-Binding Activity of Lectins Using Polyamidoamine Dendrimer Conjugated with Carbohydrates //BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY. 2012. Т.76. №10. С. 1999-2001.

The carbohydrate-binding activity of lectins was examined using polyamidoamine dendrimer conjugated with carbohydrates (sugar-PD). When a C-type lectin, CEL-IV, was mixed with melibiose-PD, large complexes with a diameter of about 1 mu m were formed. Changes in the amount of CEL-IV/melibiose-PD complex as an indication of lectin activity were measured sensitively by Rayleigh scattering. The carbohydrate specificity of the lectin was determined on the basis of inhibition of complex-formation by individual carbohydrates. It is suggested that various lectins can also be measured using sugar-PDs to which different carbohydrates are attached.

Hosseini, Hadi; Mahyari, Mojtaba; Bagheri, Akbar; et al. Pd and PdCo alloy nanoparticles supported on polypropylenimine dendrimer-grafted graphene: A highly efficient anodic catalyst for direct formic acid fuel cells // JOURNAL OF POWER SOURCES. 2014. Т. 247. №-. С. 70-77.

For the first time, Pd and PdCo alloy nanoparticles supported on polypropylenimine dendrimer-grafted graphene (Pd and PdCo/PPI-g-G) are prepared and characterized with Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The electrocatalytic activity of Pd and PdCo/PPI-g-G are investigated in terms of formic acid electrooxidation in H2SO4 aqueous solution. The PdCo/PPI-g-G shows much higher formic acid oxidation activities in comparison with Pd/PPI-g-G, and it is more resistant to the surface poisoning. This improved electrocatalytic performance may be due to the fine dispersion of PdCo alloy nanoparticles and bifunctional effect. The kinetic parameters such as charge transfer coefficient and the diffusion coefficient of formic acid are estimated under the quasi steady-state conditions. (C) 2013 Elsevier B.V. All rights reserved.

Ionov, Maksim; Garaiova, Zuzana; Waczulikova, Iveta; et al. siRNA carriers based on carbosilane dendrimers affect zeta potential and size of phospholipid vesicles//BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES. 2012. Т. 1818. №9. С. 2209-2216.

One of the major limitations in gene therapy is an inability of naked siRNA to passively diffuse through negatively charged cell membranes. Therefore, the siRNA transport into a cell requires efficient carriers. In this work we analyzed the charge-dependent interaction of the complexes of cationic carbosilane dendrimers (CBD) and anti-HIV siRNA (dendriplexes) with the model membranes large unilamellar vesicles (LUV). We used the second generation of branched with CBD carbon-silicon bonds (CBD-CS) which are water-stable and that of oxygen-silicon bonds (COD-OS) which are slowly hydrolyzed in aqueous solutions. The. LUVs were composed of zwitterionic dimyristoylphosphatidylcholine (DMPC), negatively charged dipalmitoylphosphatidylglycerol (DPPG) and their mixture (DMPC/DPPG, molar ratio 7:3). The interaction of dendriplexes with LUVs affected both zeta potential and size of the vesicles. The changes of these values were larger for the negatively charged LUV. COD-CS resulted in the decrease of zeta potential values to more negative ones, whereas an opposite effect took place for CBD-OS suggesting a different kind of interaction between LUVs and the dendriplexes. The results indicate that both CBD-CS and CBD-OS can be used for transport of siRNA into the cells. However. CBD-CS are preferred due to a better stability in water and improved bioavailability of siRNA on their surface.

Jose Jr. R.S., Zucolotto V., Oliveira Jr. O.N., Werner C.F., Poghossian A., Schoning M.J., Maki R.M., Paulovich F.V., De Oliveira M.C.F. USE OF INFORMATION VISUALIZATION METHODS ELIMINATING CROSS TALK IN MULTIPLE SENSING UNITS INVESTIGATED FOR A LIGHT-ADDRESSABLE POTENTIOMETRIC SENSOR//Analytical Chemistry. 2010. Т. 82. № 1. С. 61-65.

The integration of nanostructured films containing biomolecules and silicon-based technologies is a promising direction for reaching miniaturized biosensors that exhibit high sensitivity and selectivity. A challenge, however, is to avoid cross talk among sensing units in an array with multiple sensors located on a small area. In this letter, we describe an array of 16 sensing units of a light-addressable potentiometric sensor (LAPS), which was made with layer-by-layer (LbL) films of a poly(amidomine) dendrimer (PAMAM) and single-walled carbon nanotubes (SWNTs), coated with a layer of the enzyme penicillinase. A visual inspection of the data from constant-current measurements with liquid samples containing distinct concentrations of penicillin, glucose, or a buffer indicated a possible cross talk between units that contained penicillinase and those that did not With the use of multidimensional data projection techniques, normally employed in information visualization methods, we managed to distinguish the results from the modified LAPS, even in cases where the units were adjacent to each other. Furthermore, the plots generated with the interactive document map (IDMAP) projection technique enabled the distinction of the different concentrations of penicillin, from 5 mmol L-1 down to 0.5 mmol L-1. Data visualization also confirmed the enhanced performance of the sensing units containing carbon nanotubes, consistent with the analysis of results for LAPS sensors. The use of visual analytics, as with projection methods, may be essential to handle a large amount of data generated in multiple sensor arrays to achieve high performance in miniaturized systems

Kataoka, Kayoko; Arai, Tatsuo Photochemical Characteristics of Amphiphilic Stilbene Dendrimers Induced by Aggregate Formation at Very Low Concentration //CHEMISTRY LETTERS. 2013. Т. 42. №5. С. 535-537.

An amphiphilic stilbene dendrimer exists as monomer in organic solvent, but forms molecular assemblies in neutral water exhibiting excimer fluorescence and undergoes cycloaddition even in highly diluted solution of 10(-6) M.

Kavas, H.; Durmus, Z.; Tanriverdi, E.; et al. Fabrication and characterization of dendrimer-encapsulated monometallic Co nanoparticles //JOURNAL OF ALLOYS AND COMPOUNDS. 2011. Т. 509. №17. С. 5341-5348.

A series of cobalt (Co) nanoparticles were synthesized by employing PAMAM dendrimers with different generations (G 0.0-3.0) as templates and sodium borohydride as a reducing agent. Extensive characterizations of the products were done using TEM, FT-IR, VSM, TGA, and XPS. The magnetization curves have superparamagnetic non hysteric characteristic at lower fields and with nonsaturation characteristic at high fields. All XRD patterns indicate that amorphous structure of all products. The shake-up satellites are observed at higher energies of the XPS peaks. (C) 2011 Elsevier B. V. All rights reserved.

Kim, Younghoon; Kim, Sung Hoon; Tanyeri, Melikhan; et al. Dendrimer Probes for Enhanced Photostability and Localization in Fluorescence Imaging//BIOPHYSICAL JOURNAL. 2013. Т.104. №7. С. 1566-1575.

Recent advances in fluorescence microscopy have enabled high-resolution imaging and tracking of single proteins and biomolecules in cells. To achieve high spatial resolutions in the nanometer range, bright and photostable fluorescent probes are critically required. From this view, there is a strong need for development of advanced fluorescent probes with molecular-scale dimensions for fluorescence imaging. Polymer-based dendrimer nanoconjugates hold strong potential to serve as versatile fluorescent probes due to an intrinsic capacity for tailored spectral properties such as brightness and emission wavelength. In this work, we report a new, to our knowledge, class of molecular probes based on dye-conjugated dendrimers for fluorescence imaging and single-molecule fluorescence microscopy. We engineered fluorescent dendritic nanoprobes (FDNs) to contain multiple organic dyes and reactive groups for target-specific biomolecule labeling. The photophysical properties of dye-conjugated FDNs (Cy5-FDNs and Cy3-FDNs) were characterized using single-molecule fluorescence microscopy, which revealed greatly enhanced photostability, increased probe brightness, and improved localization precision in high-resolution fluorescence imaging compared to single organic dyes. As proof-of-principle demonstration, Cy5-FDNs were used to assay single-molecule nucleic acid hybridization and for immunofluorescence imaging of microtubules in cytoskeletal networks. In addition, Cy5-FDNs were used as reporter probes in a single-molecule protein pull-down assay to characterize antibody binding and target protein capture. In all cases, the photophysical properties of FDNs resulted in enhanced fluorescence imaging via improved brightness and/or photostability.


Photoinduced electron transfer (ET) and energy transfer (EnT) of a snowflake-shaped Zn-porphyrin dendrimer with anthraquinone terminals (dendrimer-1), which has four rigid ethynylene-phenylene conjugated chains covered by soft benzyl ether (BE) branches, is investigated by means of steady-state and time-resolved fluorescence measurements. Dendrimer-2 without anthraquinone terminals undergoes a nearly quantitative EnT from the excited singlet states of BE branches to the Zn-porphyrin core, where the conjugated chain plays an important role as a mediator of EnT within this antenna type dendrimer (the dendrimer effect on EnT). A comparison of the rates of charge separation via the singlet excited state of Zn-porphyrin to the anthraquinone terminals through oligo(ethynylenephenylene)s in a series of model compounds reveals considerable acceleration of the rate constants by the dendrimer architecture (the dendrimer effect on ET). This acceleration is attributed to hydrophobic interactions between the flexible BE chains within dendrimer-1, resulting in a significant conformational change into coplanar forms between the Zn-porphyrin plane and the ethynylenephenylene-anthraquinone plane.

Leshchiner, Ignaty; Boiko, Natalia; Kumar, Jayant; et al Synthesis and physical behavior of amphiphilic dendrimers with layered organization of hydrophilic and hydrophobic blocks // COLLOID AND POLYMER SCIENCE. 2013. Т. 291. №4. С. 927-936.

Amphiphilic carbosilane dendrimers with novel architectural layout have been synthesized. These dendrimers contain peripheral groups consisting of covalently bound promesogenic fragments and hydrophilic (oligoethyleneglycolic) linkages which are connected to a carbosilane core in two distinct ways: as spacer or as tail arrangement. Such molecules have a block structure where the hydrophilic and hydrophobic blocks are distributed within the dendrimer forming layers of different polarity. The hydrophilic layer is either enclosed between two hydrophobic parts of the molecule or is situated on the periphery. The synthetic strategy for achieving these structures is described. The interfacial properties of the dendrimers were studied and the influence of the dendritic structure's organization on the Langmuir film formation process is assessed.

Li, Rui; Xie, Anjian; Pang, Wenmin; et al. Host-guest interaction and nano-microstructure of spherical poly(amidoamine) dendrimer/gold hybrid colloids under gamma-ray irradiation //MATERIALS LETTERS. 2012. Т. 67. №1. С. 103-106.

This investigation shows that in absence of the chemical reductant and the other protective reagents, the host-guest interaction and the molar ratio of dendrimers/Au(3+) other than size and shape of the templates play an important role for the preparation of stable gold hybrid colloids by (60)Co gamma-ray irradiation using spherical PAMAM-G5 as nonlinear polymeric template. The hybrid colloid resultants comprised of the ordered nano-crystal and the random non-crystal part, which has been confirmed by HRTEM, display spherical structure and the polydispersity of the size distribution in the range of nanometer scale. The dendrimer/gold hybrid colloids are formed by the intramolecular and intermolecular adsorption action between PAMAM-G5 template and gold nanoparticles, respectively. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Maeno, Zen; Mitsudome, Takato; Mizugaki, Tomoo; et al. Novel Catalysis in the Internal Nanocavity of Polyamine Dendrimer for Intramolecular Michael Reaction //CHEMISTRY LETTERS. 2012. Т. 41. №8. С. 801-803.

Poly(propyleneimine) (PPI) dendrimers functionalized with C-16 alkyl chains acted as efficient tertiary amine catalysts for an intramolecular Michael reaction. The substrate was accommodated in a reactive conformation within a sterically confined nanocavity consisting of regularly arranged tertiary amino groups of the PPI dendrimers.

Merhi, Areej; Drouet, Samuel; Kerisit, Nicolas; et al. A family of fluorenyl dendrons for porphyrin dendrimers synthesis //TETRAHEDRON. 2012. Т. 68. №38. С. 7901-7910.

A series of dendrons bearing various number of fluorenyl donor groups have been synthesized. First, the reference compound 2-(bromomethyl)-9H-fluorene (8) with one fluorenyl unit, then dendron 10, with two fluorenyl arms, and finally new generation dendrons, 11 and 12, bearing four peripheral fluorenyl arms were synthesized and characterized. A series of different generations of porphyrin dendrimers, obtained from these dendrons are also presented. Preliminary results on higher generation dendrimers are reported as well. Under mild basic conditions, surprisingly, a new compound 1 incorporating a fluorenyl unit in the cycle and three pendant fluorenyl arms was obtained by an intramolecular reaction of brominated tetrapod dendron 12. (C) 2012 Elsevier Ltd. All rights reserved.

Mizugaki, Tomoo; Kibata, Takayuki; Mitsudome, Takato; et al. Size Selective Synthesis of Subnano Pd Clusters Using Core [Poly(propylene imine)]-Shell [Poly(benzyl ether)] Hybrid Dendrimers //CHEMISTRY LETTERS. 2013. Т. 42. №3. С. 313-315.


Nandy, Bidisha; Maiti, Prahal K. DNA Compaction by a Dendrimer //JOURNAL OF PHYSICAL CHEMISTRY B. 2011. Т. 115. №2. С. 217-230.

At physiological pH, a PAMAM dendrimer is positively charged and can effectively bind negatively charged DNA. Currently, there has been great interest in understanding this complexation reaction both for fundamental (as a model for complex biological reactions) as well as for practical (as a gene delivery material and probe for sensing DNA sequence) reasons. Here, we have studied the complexation between double-stranded DNA (dsDNA) and various generations of PAMAM dendrimers (G3-05) through atomistic molecular dynamics simulations in the presence of water and ions. We report the compaction of DNA on a nanosecond time scale. This is remarkable, given the fact that such a short DNA duplex with a length close to 13 nm is otherwise thought to be a rigid rod. Using several nanoseconds long MD simulations, we have observed various binding modes of dsDNA and dendrimers for various generations of PAMAM dendrimers at varying charge ratios, and it confirms some of the binding modes proposed earlier. The binding is driven by the electrostatic interaction, and the larger the dendrimer charge, the stronger the binding affinity. As DNA wraps/binds to the dendrimer, counterions originally condensed onto DNA (Na+) and the dendrimer (Cl(-)) get released. We calculate the entropy of counterions and show that there is gain in entropy due to counterion release during the complexation. MD simulations demonstrate that, when the charge ratio is greater than 1 (as in the case of the G5 dendrimer), the optimal wrapping of DNA is observed. Calculated binding energies of the complexation follow the trend G5 > 04 > 03, in accordance with the experimental data. For a lower-generation dendrimer, such as G3, and, to some extent, for G4 also, we see considerable deformation in the dendrimer structure due to their flexible nature. We have also calculated the various helicoidal parameters of DNA to study the effect of dendrimer binding on the structure of DNA. The B form of the DNA is well preserved in the complex, as is evident from various helical parameters, justifying the use of the PAMAM dendrimer as a suitable delivery vehicle.

Nemanashi, Mulisa; Meijboom, Reino Synthesis and characterization of Cu, Ag and Au dendrimer-encapsulated nanoparticles and their application in the reduction of 4-nitrophenol to 4-aminophenol// JOURNAL OF COLLOID AND INTERFACE SCIENCE. 2013. Т. 389. №-. С. 260-267.

Here, we report on the synthesis, characterization and catalytic evaluation of Cu, Ag and Au dendrimer encapsulated nanoparticles (DENs). Generations 4-6 of PAMAM-OH and PAMAM-NH2 were used as templating agents for the synthesis of Cu and Ag-DENS respectively. Generation 4 PAMAM-NH2 dendrimers were used for the synthesis of Au-DENs. These prepared DENs were characterized using UV visible (UV-vis) spectroscopy as well as a high resolution transmission electron microscopy (HRTEM). The catalytic activity of these DENs was evaluated on the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AMP) by sodium borohydride (NaBH4). The reaction was monitored by UV-vis spectroscopy at lambda 400 nm. These prepared DENs were found to exhibit good activity for this reduction reaction. (C) 2012 Elsevier Inc. All rights reserved.

Opitz, Armin W.; Czymmek, Kirk J.; Wickstrom, Eric; et al. Uptake, efflux, and mass transfer coefficient of fluorescent PAMAM dendrimers into pancreatic cancer cells//BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES. 2013. Т. 1828. №2. С.294-301.

Targeted delivery of imaging agents to cells can be optimized with the understanding of uptake and efflux rates. Cellular uptake of macromolecules is studied frequently with fluorescent probes. We hypothesized that the internalization and efflux of fluorescently labeled macromolecules into and out of mammalian cells could be quantified by confocal microscopy to determine the rate of uptake and efflux, from which the mass transfer coefficient is calculated. The cellular influx and efflux of a third generation poly(amido amine) (PAMAM) dendrimer labeled with an Alexa Fluor 555 dye was measured in Capan-1 pancreatic cancer cells using confocal fluorescence microscopy. The Capan-1 cells were also labeled with 5-chloromethylfluorescein diacetate (CMFDA) green cell tracker dye to delineate cellular boundaries. A dilution curve of the fluorescently labeled PAMAM dendrimer enabled quantification of the concentration of dendrimer in the cell. A simple mass transfer model described the uptake and efflux behavior of the PAMAM dendrimer. The effective mass transfer coefficient was found to be 0.054+/-0.043 mu m/min, which corresponds to a rate constant of 0.035+/-0.023 min(-1) for uptake of the PAMAM dendrimer into the Capan-1 cells. The effective mass transfer coefficient was shown to predict the efflux behavior of the PAMAM dendrimer from the cell if the fraction of labeled dendrimer undergoing non-specific binding is accounted for. This work introduces a novel method to quantify the mass transfer behavior of fluorescently labeled macromolecules into mammalian cells.

Pu, Yu-Ji; Yuan, Hui; Yang, Ming; et al. Synthesis of peptide dendrimers with polyhedral oligomeric silsesquioxane cores via click chemistry //CHINESE CHEMICAL LETTERS. 2013. Т. 24. №10. С. 917-920.

Inorganic polyhedral oligomeric silsesquioxane (PUSS) was used as the core for the synthesis of poly(L-lysine) peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, H-1 NMR, FTIR, GPC and DLS. (C) 2013 Zhong-Wei Gu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Raeder, Hans Joachim; Thi-Thanh-Tam Nguyen; Muellen, Klaus ALDI-TOF Mass Spectrometry of Polyphenylene Dendrimers up to the Megadalton Range. Elucidating Structural Integrity of Macromolecules at Unrivaled High Molecular Weights //MACROMOLECULES. 2014. Т. 47. №4. С. 1240-1248.

A complete homologous series of polyphenylene dendrimers up to the ninth generation (G9) corresponding to a theoretical molecular weight of 1.9 MDa was characterized by MALDI-TOF mass spectrometry. Mass spectrometry of synthetic polymers at extreme high masses is still uncommon to date and the underlying probable reasons are discussed. The measurements provided insight into the structural integrity, especially for the highest generations which could not be obtained by standard analytical tools for polymer characterization, such as gel permeation chromatography. The degree of structural integrity was elucidated by comparison of the measured molecular weights with theoretical molecular weights, calculated for the perfect structures. As a result, the dendrimers own structural perfection up to G4 and show increasing deviations with each higher generation starting at G5. The deviations could be partially attributed to a systematic error of the measurements but mainly to an increasing number of missing branches inside the dendrimers. The detected changes within the homologues series were discussed with respect to polymer-chemical aspects of the divergent route of dendrimer synthesis. Overall the whole dendrimer series shows very narrow polydispersity values below 1.005 which confirm the high structural integrity of these giant molecules up to a diameter of 33 nm, which can be considered as molecularly defined nanosized particles.

Salamonczyk, Grzegorz M. New water-soluble polyanionic dendrimers-phosphoric and 1,3,5-benzenetricarboxylic acid derivatives //TETRAHEDRON. 2012. Т. 68. №49. С. 10209-10217.

Simple, very efficient, and having some aspects of generality, synthesis of water-soluble, polyanionic dendrimeric polyesters with different size, polarity, and flexibility is described. These macromolecular compounds consisting of phosphate or thiophosphate ester units and 1,3,5-benzenetricarboxylic acid building blocks may find potential applications as pharmaceutical agents. Synthesized the title polyanionic dendrimers possess charged carboxyl functional groups on the surface and were obtained, in high yields, from previously prepared series of new phosphorus-based dendrimeric polyols. The key monomers applied in this project were 1,3,5-benzenetricarboxylic acid dibenzyl ester and 1,3,5-benzenetricarboxylic acid bis(4-methoxybenzyl) ester. Both worked as the essential precursors of the dendrimer polyanionic surface. (C) 2012 Elsevier Ltd. All rights reserved.

Sezginturk, Mustafa Kemal; Uygun, Zihni Onur An impedimetric vascular endothelial growth factor biosensor-based PAMAM/cysteamine-modified gold electrode for monitoring of tumor growth//ANALYTICAL BIOCHEMISTRY. 2012. Т. 423. №2. С. 277-285.

In the present work, we have developed a new biosensor based on fourth-generation (G4) PAMAM dendrimers for the analysis of vascular endothelial growth factor (VEGF). First, the PAMAM dendrimers were covalently attached to a cysteamine-modified Au electrode by glutaraldehyde. With the help of the amino groups located on its surface, vascular endothelial growth factor receptor-1 (VEGF-R1) was immobilized via glutaraldehyde cross-linking. VEGF-R1 loading was investigated to identify the optimal VEGF-R1 immobilization conditions for the best sensitivity of the new biosensor. In addition, Kramers-Kronig transforms were also analyzed for immobilization and measurement processes. The biosensor had a linear range of 5 to 125 pg/mL VEGF. The fabricated biosensor had good repeatability and reproducibility. Finally, the results for artificial serum samples measured by the present biosensor showed a good recovery for VEGF detection.

Siyad, M. A.; Kumar, G. S. Vinod Synthetic evaluation of disulphide-bonded sarafotoxin on a poly(oxy ether) grafted dendrimeric poly(alkyl amine) support for polymer assisted organic synthesis //ORGANIC & BIOMOLECULAR CHEMISTRY. 2013. Т. 11. №29. С. 4860-4870.

The present paper describes the synthesis, characterization and assessment of a novel class of insoluble polymeric polystyrene supports which combines polar poly(ethylene glycol)dimethacrylate as a cross-linker and poly(ethylene glycol) grafted poly(N,N-bisethylamine) as a dendritic template. Poly(N,N-bisethylamine) dendrimers were generated by a series of reactions such as Schiff base integration, acidolysis, diazotization and thionyl chloride treatment. The same successive sequences of reactions have been followed for second generation dendrimers also and subjected to PEGylation (PEG 600) to achieve the desirable physico-chemical properties. The applicability of the novel PEGylated dendrimer support was demonstrated by synthesizing linear as well as disulfide bonded peptides in high yields and purities.

Takizawa, Tsutomu; Arai, Tatsuo Control of Photoisomerization in Water-soluble Stilbene Dendrimers by Conformation of Dendrons: How Water-soluble Dendrimer Molecules Are Dissolved in Water //CHEMISTRY LETTERS. 2012. Т. 41. №4. С. 415-417.



Body image: Self-activating Huisgen 1,3-dipolar cycloaddition and 6? azaelectrocyclization of lysine-based dendrimers (see picture) enable the in vivo dynamics and organ-specific accumulation of N-glycans to be visualized. The sugar structure and glycosyl bond linkages of N-glycans control the whole-body trafficking of the clusters in nude mice and a cancer model.

Tiriveedhi V., Kitchens K.M., Nevels K.J., Butko P., Ghandehari H. KINETIC ANALYSIS OF THE INTERACTION BETWEEN POLY(AMIDOAMINE) DENDRIMERS AND MODEL LIPID MEMBRANES//Biochimica et Biophysica Acta (BBA) - Biomembranes. 2011. Т. 1808. № 1. С. 209-218.

We used fluorescence spectroscopy and surface tensiometry to study the interaction between low-generation (G1 and G4) poly(amidoamine) (PAMAM) dendrimers, potential vehicles for intracellular drug delivery, and model lipid bilayers. Membrane association of fluorescently labeled dendrimers, measured by fluorescence anisotropy, increased with increasing size of the dendrimer and with increasing negative charge density in the membrane, indicating the electrostatic nature of the interaction. When the membrane was doped with pyrene-labeled phosphatidyl glycerol (pyrene-PG), pyrene excimer fluorescence demonstrated a dendrimer-induced selective aggregation of negatively charged lipids when the membrane was in the liquid crystalline state. A nonlinear Stern-Volmer quenching of dendrimer fluorescence with cobalt bromide suggested a dendrimer-induced aggregation of lipid vesicles, which increased with the dendrimer's generation number. Surface tensiometry measurements showed that dendrimers penetrated into the lipid monolayer only at subphysiologic surface pressures (< 30 mN/m). We conclude that the low-generation PAMAM dendrimers associate with lipid membranes predominantly electrostatically, without significantly compromising the bilayer integrity. They bind stronger to membranes with higher fluidity and lower surface pressure, which are characteristic of rapidly dividing cells.

Toita, Riki; Mori, Takeshi; Naritomi, Yuki; et al. Fluorometric detection of protein kinase C alpha activity based on phosphorylation-induced dissociation of a polyion complex//ANALYTICAL BIOCHEMISTRY. 2012. Т. 424. №2. С. 130-136.

Here, we report the fluorometric detection of protein kinase C alpha (PKC alpha) activity in a cancerous cell lysate using a polyion complex (PIC) composed of a quencher (BHQ3)-modified chondroitin sulfate [CS(X)] and a dendrimer modified with a cationic peptide substrate (FKKQGSFAKKK-NH2) and a near infrared (NIR) fluorophore (Cy5.5) (polymer 1). When polymer 1 formed the PIC with CS(X) through electrostatic interactions, the NIR fluorescence was quenched effectively via Forster resonance energy transfer (FRET) between Cy5.5 and BHQ3. However, this quenched fluorescence was recovered when the pendant peptides in polymer 1 were phosphorylated with PKC alpha due to the dissociation of the PIC. When PKC alpha was added to the PIC dispersion, a significant increase in fluorescence intensity was observed, whereas its fluorescence increase was inhibited with a PKC alpha inhibitor in a concentration-dependent manner. Furthermore, our PIC was robust enough to measure PKC alpha activity in a cancerous cellular lysate without purification. The PKC alpha-responsive PIC offers a simple, rapid, sensitive, and robust approach to detect PKC alpha activity in crude cellular lysates that would be suitable for drug screening formats and cancer diagnosis using crude cellular lysates.

Wu, Huixia; Liu, Miaomiao; Wei, Chenyang; et al. Carbon-nanotube-supported Ag and Cu2O nanoparticles: Dendrimer-mediated synthesis and their broadband optical limiting properties //MATERIALS CHEMISTRY AND PHYSICS. 2012. Т. 134. №1. С. 183-189.

Multiwalled carbon nanotubes (MWCNTs) were covalently functionalized with fourth-generation poly(amido amine) (PAMAM) dendrimers with a trimesyl core (DT4), and the as-synthesized MWCNT-DT4 was used as the template for in situ growth of Ag and Cu2O nanoparticles on MWCNTs. Extensive characterizations of the resultant hybrids have been performed using X-ray diffraction, transmission electron microscopy (TEM), high resolution TEM, energy dispersive X-ray spectroscopy, selected area electron diffraction, thermal gravimetric analysis, and X-ray photoelectron spectroscopy. The side-wall of the nanotubes was uniformly coated with the nanoparticles with mean sizes of 7-8 nm. The optical limiting property measurements of the nanoparticle-modified MWCNTs were carried out by the open-aperture z-scan technique. The results demonstrate that the samples suspended in water show broadband CL performance, and their CL behavior is better than that of MWCNT-DT4 in water due to the presence of Ag and Cu2O nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.

Wu, Wenbo; Qin, Jingui; Li, Zh New design strategies for second-order nonlinear optical polymers and dendrimers //POLYMER. 2013. Т. 54. №17. С. 4351-4382.

The development of organic/polymeric materials with second-order nonlinear optical (NLO) performance became more and more important, due to the increasing potential for the applications in photonic devices and many advantages over conventional inorganic crystalline materials in the last few decades, especially after 1980s. So far, the NLO polymers have developed from the initial guest-host systems, to side-chain polymers, cross-linked systems, dendrimers and dendronized polymers, and then to hyperbranched polymers and even self-assembly systems. As a result, the NLO coefficients have been improved from lower than 10 pm/V to above 300 pm/V. In this article, we would like to review the development of NLO polymers, especially some recently reported design strategies, such as "site-isolation principle", the concept of "suitable isolation group", the special effect of "isolation chromophore", Ar-Ar-F self-assembly effect, etc. (c) 2013 Elsevier Ltd. All rights reserved.

Xu XiangHui; Li CaiXia; Li HaiPing; et al. Polypeptide dendrimers: Self-assembly and drug delivery //SCIENCE CHINA-CHEMISTRY. 2011. Т. 54. №2. С. 326-333.

Amphiphilic dendritic poly(glutamic acid)-b-polyphenylalanine copolymers were synthesized using generation 3 dendritic poly(glutamic acid) as the macroinitiator in the ring-opening polymerization of NCA-Phe. The block copolymers self-assembled micelles with polyphenylalanine segments as core and dendritic poly(glutamic acid) segments as shell. The biocompatibility of the micelles was studied. The release of the anticancer drug doxorubicin from the micelles was investigated in vitro. The results showed that the sustaining release of the drug could last for 60 h. The micellar drug release system was efficient in inhibiting the proliferation of HepG2 liver cancer cells, 75% cancer cells were killed under appropriate in vitro incubation.

Zhang, Jian; Zhou, Xichun Novel 3-dimensional dendrimer platform for glycolipid microarray//BIOSENSORS & BIOELECTRONICS. 2011. Т. 28. №1. С. 355-361.

Glycolipids are important biological molecules that modulate cellular recognitions and pathogen adhesions. In this paper, we report a sensitive glycolipid microarray for non-covalently immobilizing glycolipids on a microarray substrate and we perform a set of immunoassays to explore glycolipid-protein interactions. This substrate utilizes a three-dimensional hydrazide-functionalized dendrimer monolayer attached onto a microscopic glass surface, which possesses the characteristics to adsorb glycoliplids non-covalently and facilitates multivalent attributes on the substrate surface. In the proof-of-concept experiments, gangliosides such as GM1, FucGM1, GM3, GD1b, GT1b, and GQ1b, and a lipoarabinomannan were tested on the substrate and interrogated with toxins and antibodies. The resulting glycolipid microarrays exhibited hypersensitivity and specificity for detection of glycolipid-protein interactions. In particular, a robust and specific binding of a pentameric cholera toxin B subunit to the GM1 glycolipid spotted on the array has demonstrated its superiority in sensitivity and specificity. In addition, this glycolipid microarray substrate was used to detect lipoarabinomannan in buffer within a limit-of-detection of 125 ng/mL Furthermore, Mycobacterium tuberculosis (Mtb) Lipoarabinomannan was tested in human urine specimens on this platform, which can effectively identify urine samples either infected or not infected with Mtb. The results of this work suggest the possibility of using this glycolipid microarray platform to fabricate glycoconjugate microarrays, which includes free glycans and glycolipids and potential application in detection of pathogen and toxin. (C) 2011 Elsevier B.V. All rights reserved.

Zhang, YR; Pang, L; Ma, C; Tu, Q; Zhang, R ; Saeed, E; Mahmoud, A; Wang, JY Small Molecule-Initiated Light-Activated Semiconducting Polymer Dots: An Integrated Nanoplatform for Targeted Photodynamic Therapy and Imaging of Cancer Cells//ANALYTICAL CHEMISTRY. 2014. Т. 86. №6. С. 3092-3099.

Photodynamic therapy (PDT) is a noninvasive and light-activated method for cancer treatment. Two of the vital parameters that govern the efficiency of PDT are the light irradiation to the photosensitizer and visual detection of the selective accumulation of the photosensitizer in malignant cells. Herein, we prepared an integrated nanoplatform for targeted PDT and imaging of cancer cells using folic acid and horseradish peroxidase (HRP)-bifunctionalized semiconducting polymer dots (FH-Pdots). In the FH-Pdots, meta-tetra(hydroxyphenyl)-chlorin (m-THPC) was used as photosensitizer to produce cytotoxic reactive oxygen species (ROS); fluorescent semiconducting polymer poly[2-methoxy-5((2-ethylhexyl)oxy)-p-phenylenevinylene] was used as light antenna and hydrophobic matrix for incorporating m-THPC, and amphiphilic Janus dendrimer was used as a surface functionalization agent to conjugate HRP and aminated folk acid onto the surface of FH-Pdots. Results indicated that the doped m-THPC can be simultaneously excited by the on-site luminol-H2O2-HRP chemiluminescence system through two paths. One is directly through chemiluminescence resonance energy transfer (CRET), and the other is through CRET and subsequent fluorescence resonance energy transfer. In vitro PDT and specificity studies of FH-Pdots using a standard transcriptional and translational assay against MCF-7 breast cancer cells, C6 glioma cells, and NIH 3T3 fibroblast cells demonstrated that cell viability decreased with increasing concentration of FH-Pdots. At the same concentration of FH-Pdots, the decrease in cell viability was positively relevant with increasing folate receptor expression. Results from in vitro fluorescence imaging exhibited that more FH-Pdots were internalized by cancerous MCF-7 and C6 cells than by noncancerous NIH 3T3 cells. All the results demonstrate.

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