Nanostructured graphene/Fe₃O₄ incorporated polyaniline as a high performance shield against electromagnetic pollution.

PubMed

Singh, Kuldeep; Ohlan, Anil; Pham, Viet Hung; R, Balasubramaniyan; Varshney, Swati; Jang, Jinhee; Hur, Seung Hyun; Choi, Won Mook; Kumar, Mukesh; Dhawan, S K; Kong, Byung-Seon; Chung, Jin Suk

2013-03-21

The development of high-performance shielding materials against electromagnetic pollution requires mobile charge carriers and magnetic dipoles. Herein, we meet the challenge by building a three-dimensional (3D) nanostructure consisting of chemically modified graphene/Fe3O4(GF) incorporated polyaniline. Intercalated GF was synthesized by the in situ generation of Fe3O4 nanoparticles in a graphene oxide suspension followed by hydrazine reduction, and further in situ polymerization with aniline to form a polyaniline composite. Spectroscopic analysis demonstrates that the presence of GF hybrid structures facilitates strong polarization due to the formation of a solid-state charge-transfer complex between graphene and polyaniline. This provides proper impedance matching and higher dipole interaction, which leads to the high microwave absorption properties. The higher dielectric loss (ε'' = 30) and magnetic loss (μ'' = 0.2) contribute to the microwave absorption value of 26 dB (>99.7% attenuation), which was found to depend on the concentration of GF in the polyaniline matrix. Moreover, the interactions between Fe3O4, graphene and polyaniline are responsible for superior material characteristics, such as excellent environmental (chemical and thermal) degradation stability and good electric conductivity (as high as 260 S m(-1)).

Polyaniline nanofibers: a unique polymer nanostructure for versatile applications.

PubMed

Li, Dan; Huang, Jiaxing; Kaner, Richard B

2009-01-20

Known for more than 150 years, polyaniline is the oldest and potentially one of the most useful conducting polymers because of its facile synthesis, environmental stability, and simple acid/base doping/dedoping chemistry. Because a nanoform of this polymer could offer new properties or enhanced performance, nanostructured polyaniline has attracted a great deal of interest during the past few years. This Account summarizes our recent research on the syntheses, processing, properties, and applications of polyaniline nanofibers. By monitoring the nucleation behavior of polyaniline, we demonstrate that high-quality nanofibers can be readily produced in bulk quantity using the conventional chemical oxidative polymerization of aniline. The polyaniline nanostructures formed using this simple method have led to a number of exciting discoveries. For example, we can readily prepare aqueous polyaniline colloids by purifying polyaniline nanofibers and controlling the pH. The colloids formed are self-stabilized via electrostatic repulsions without the need for any chemical modification or steric stabilizer, thus providing a simple and environmentally friendly way to process this polymer. An unusual nanoscale photothermal effect called "flash welding", which we discovered with polyaniline nanofibers, has led to the development of new techniques for making asymmetric polymer membranes and patterned nanofiber films and creating polymer-based nanocomposites. We also demonstrate the use of flash-welded polyaniline films for monolithic actuators. Taking advantage of the unique reduction/oxidation chemistry of polyaniline, we can decorate polyaniline nanofibers with metal nanoparticles through in situ reduction of selected metal salts. The resulting polyaniline/metal nanoparticle composites show promise for use in ultrafast nonvolatile memory devices and for chemical catalysis. In addition, the use of polyaniline nanofibers or their composites can significantly enhance the sensitivity

EPR investigations of silicon carbide nanoparticles functionalized by acid doped polyaniline

NASA Astrophysics Data System (ADS)

Karray, Fekri; Kassiba, Abdelhadi

2012-06-01

Nanocomposites (SiC-PANI) based on silicon carbide nanoparticles (SiC) encapsulated in conducting polyaniline (PANI) are synthesized by direct polymerization of PANI on the nanoparticle surfaces. The conductivity of PANI and the nanocomposites was modulated by several doping levels of camphor sulfonic acid (CSA). Electron paramagnetic resonance (EPR) investigations were carried out on representative SiC-PANI samples over the temperature range [100-300 K]. The features of the EPR spectra were analyzed taking into account the paramagnetic species such as polarons with spin S=1/2 involved in two main environments realized in the composites as well as their thermal activation. A critical temperature range 200-225 K was revealed through crossover changes in the thermal behavior of the EPR spectral parameters. Insights on the electronic transport properties and their thermal evolutions were inferred from polarons species probed by EPR and the electrical conductivity in doped nanocomposites.

Polyaniline-polypyrrole composites with enhanced hydrogen storage capacities.

PubMed

Attia, Nour F; Geckeler, Kurt E

2013-06-13

A facile method for the synthesis of polyaniline-polypyrrole composite materials with network morphology is developed based on polyaniline nanofibers covered by a thin layer of polypyrrole via vapor phase polymerization. The hydrogen storage capacity of the composites is evaluated at room temperature exhibits a twofold increase in hydrogen storage capacity. The HCl-doped polyaniline nanofibers exhibit a storage capacity of 0.46 wt%, whereas the polyaniline-polypyrrole composites could store 0.91 wt% of hydrogen gas. In addition, the effect of the dopant type, counteranion size, and the doping with palladium nanoparticles on the storage properties are also investigated. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermoelectric properties of conducting polyaniline/BaTiO3 nanoparticle composite films

NASA Astrophysics Data System (ADS)

Anno, H.; Yamaguchi, K.; Nakabayashi, T.; Kurokawa, H.; Akagi, F.; Hojo, M.; Toshima, N.

2011-05-01

Conducting polyaniline (PANI)/BaTiO3 nanoparticle composite films with different molar ratio values R=1, 5, 10, and 100 have been prepared on a quartz substrate by casting the m-cresol solution of PANI, (±)-10-camphorsulfonic acid (CSA) and BaTiO3 nanoparticle with an average diameter of about 20 nm. The CSA-doped PANI/BaTiO3 composite films were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and UV-Vis transmission spectroscopy. The Seebeck coefficient and the electrical conductivity of the films with different R values, together with CSA-doped PANI films, were measured in the temperature range from room temperature to ~400 K. The relation between the Seebeck coefficient and the electrical conductivity in the composite films are discussed from a comparison of them with those of CSA-doped PANI films and other PANI composite films.

Thermally conductive of nanofluid from surfactant doped polyaniline nanoparticle and deep eutectic ionic liquid

NASA Astrophysics Data System (ADS)

Siong, Chew Tze; Daik, Rusli; Hamid, Muhammad Azmi Abdul

2014-09-01

Nanofluid is a colloidal suspension of nano-size particles in a fluid. Spherical shape dodecylbenzenesulfonic acid doped polyaniline (DBSA-PANI) nanoparticles were synthesized via reverse micellar polymerization in isooctane with average size of 50 nm- 60 nm. The aim of study is to explore the possibility of using deep eutectic ionic liquid (DES) as a new base fluid in heat transfer application. DES was prepared by heating up choline chloride and urea with stirring. DES based nanofluids containing DBSA-PANI nanoparticles were prepared using two-step method. Thermal conductivity of nanofluids was measured using KD2 Pro Thermal Properties Analyzer. When incorporated with DBSA-PANI nanoparticles, DES with water was found to exhibit a bigger increase in thermal conductivity compared to that of the pure DES. The thermal conductivity of DES with water was increased by 4.67% when incorporated with 0.2 wt% of DBSA-PANI nanoparticles at 50°C. The enhancement in thermal conductivity of DES based nanofluids is possibly related to Brownian motion of nanoparticles as well as micro-convection of base fluids and also interaction between dopants and DES ions.

Facile synthesis of palladium nanoparticle doped polyaniline nanowires in soft templates for catalytic applications

NASA Astrophysics Data System (ADS)

Kshirasagar, Krushna J.; Markad, Uddhav S.; Saha, Abhijit; Sharma, Kiran Kumar K.; Sharma, Geeta K.

2017-02-01

Palladium nanoparticles doped polyaniline (Pd-PANI) nanocomposite (NCs) is synthesized in surfactant based liquid crystalline mesophase by chemical oxidation followed by radiolysis. The confinement of the liquid crystalline mesophase facilitates polymerization of aniline monomers and their 1D growth into polyaniline (PANI) nanowires by using ammonium persulfate. The PANI nanowires have an average diameter of 30-40 nm. The in situ radiolytic reduction of palladium ions ensures uniform size distribution of the palladium (Pd) nanoparticles on the surface of the PANI nanowires. The synthesized Pd-PANI nanocomposites show wire like structures of PANI (diameter ~30-40 nm) on which Pd nanoparticles of the size 10 nm are decorated. The identical average diameter of the PANI nanowires before and post gamma irradiation suggest high stability of the PANI nanowires in liquid crystalline mesophase. Surface characterization of the NCs were carried out using BET and XPS. The catalytic activity of Pd-PANI NCs are investigated in the reduction of methylene blue (MB) and 4-nitro phenol (4-NP) by sodium borohydride (NaBH4). The kinetics of the Pd-PANI NCs catalysed reactions are analysed using the Langmuir-Hinshelwood model. The apparent rate constant (k app) for the MB and 4-NP reduction reactions is 29  ×  10-3 s-1 and 20  ×  10-3 s-1 respectively with an actual Pd catalyst loading of 2.665  ×  10-4 ppm. Further, the recyclability of the Pd-PANI NCs catalyst in both the reduction reactions shows the stability of the catalyst up to four reaction cycles tested in this investigation and the multifunctional nature of the catalyst. The study provides a new approach for the directional synthesis of conducting polymer-metal nanocomposites and their possible application as a nanocatalyst in environmental remediation.

Synthesis and electrorheological characteristics of polyaniline/organoclay nanoparticles via Pickering emulsion polymerization

NASA Astrophysics Data System (ADS)

Fang, F. F.; Liu, Y. D.; Choi, H. J.

2010-12-01

Conducting polymer/inorganic composite particles have been regarded as a potential candidate material for electrorheological (ER) fluids when dispersed in non-conducting oils due to their synergistic physical properties such as enhanced thermal stability and high dielectric properties. In this study, we fabricated polyaniline (PANI)/clay nanoparticles with unique core-shell structure via Pickering emulsion in the phase of toluene by adopting exfoliated clay as a stabilizer. Successfully synthesized PANI nanospheres which were initialized by oil-soluble benzoyl peroxide possess a polydispersed size distribution of particles ranging from 200 nm to 1 µm. Surface morphology was revealed by SEM images in which some clay sheets were found to wrap the PANI nanoparticles compactly. TEM images explicitly confirm the position of exfoliated clay layers around the nanospheres. In addition, some nano-scaled particles showed an irregular shape because clay plates are difficult to bend while wrapping the very tiny PANI nanoparticles, so the x-ray diffraction (XRD) pattern did not indicate any obvious sharp peak, demonstrating the nearly completely exfoliated clay layers. Besides these, thermal gravimetric analysis (TGA) data also gave additional information on thermal stability and composition. Finally, the ER fluid was prepared by dispersing PANI/clay nanoparticles in silicone oil and the ER performance was investigated via a rotational rheometer under an applied electric field.

New nanocomposites of polystyrene with polyaniline doped with lauryl sulfuric acid

NASA Astrophysics Data System (ADS)

Pud, A. A.; Nikolayeva, O. A.; Vretik, L. O.; Noskov, Yu. V.; Ogurtsov, N. A.; Kruglyak, O. S.; Fedorenko, E. A.

2017-08-01

This work is concentrated on synthesis and investigation of new core-shell nanocomposites of polystyrene (PS) with doped polyaniline (PANI). The latex containing PS nanoparticles with sizes of 15-30 nm was prepared by microemulsion polymerization of styrene in water media. The PS/PANI nanocomposites were synthesized by chemical oxidative polymerization of aniline in the PS latex media in a presence of lauryl sulfuric acid (LSA), which served as both dopant and plasticizer. The real content of PANI in the synthesized nanocomposites was determined by UV-Vis spectroscopy method. The composition of the nanocomposites and oxidation state of the doped polyaniline were characterized by FTIR spectroscopy. The core-shell morphology of the nanocomposite nanoparticles was proved by transmission and scanning electron microscopy. It was found that conductivity and thermal behavior in air of these nanocomposites not only nonlinearly depended on the doped polyaniline content but also were strongly effected both by plasticizing properties of the acid-dopant and presence of the polyaniline shell. A possibility of application of these nanocomposites as sensor materials has been demonstrated.

Nanoparticles modified with multiple organic acids

DOEpatents

Cook, Ronald Lee [Lakewood, CO; Luebben, Silvia DeVito [Golden, CO; Myers, Andrew William [Arvada, CO; Smith, Bryan Matthew [Boulder, CO; Elliott, Brian John [Superior, CO; Kreutzer, Cory [Brighton, CO; Wilson, Carolina [Arvada, CO; Meiser, Manfred [Aurora, CO

2007-07-17

Surface-modified nanoparticles of boehmite, and methods for preparing the same. Aluminum oxyhydroxide nanoparticles are surface modified by reaction with selected amounts of organic acids. In particular, the nanoparticle surface is modified by reactions with two or more different carboxylic acids, at least one of which is an organic carboxylic acid. The product is a surface modified boehmite nanoparticle that has an inorganic aluminum oxyhydroxide core, or part aluminum oxyhydroxide core and a surface-bonded organic shell. Organic carboxylic acids of this invention contain at least one carboxylic acid group and one carbon-hydrogen bond. One embodiment of this invention provides boehmite nanoparticles that have been surface modified with two or more acids one of which additional carries at least one reactive functional group. Another embodiment of this invention provides boehmite nanoparticles that have been surface modified with multiple acids one of which has molecular weight or average molecular weight greater than or equal to 500 Daltons. Yet, another embodiment of this invention provides boehmite nanoparticles that are surface modified with two or more acids one of which is hydrophobic in nature and has solubility in water of less than 15 by weight. The products of the methods of this invention have specific useful properties when used in mixture with liquids, as filler in solids, or as stand-alone entities.

Nanoparticles modified with multiple organic acids

NASA Technical Reports Server (NTRS)

Luebben, Silvia DeVito (Inventor); Cook, Ronald Lee (Inventor); Wilson, Carolina (Inventor); Meiser, Manfred (Inventor); Myers, Andrew William (Inventor); Smith, Bryan Matthew (Inventor); Elliott, Brian John (Inventor); Kreutzer, Cory (Inventor)

2007-01-01

Surface-modified nanoparticles of boehmite, and methods for preparing the same. Aluminum oxyhydroxide nanoparticles are surface modified by reaction with selected amounts of organic acids. In particular, the nanoparticle surface is modified by reactions with two or more different carboxylic acids, at least one of which is an organic carboxylic acid. The product is a surface modified boehmite nanoparticle that has an inorganic aluminum oxyhydroxide core, or part aluminum oxyhydroxide core and a surface-bonded organic shell. Organic carboxylic acids of this invention contain at least one carboxylic acid group and one carbon-hydrogen bond. One embodiment of this invention provides boehmite nanoparticles that have been surface modified with two or more acids one of which additional carries at least one reactive functional group. Another embodiment of this invention provides boehmite nanoparticles that have been surface modified with multiple acids one of which has molecular weight or average molecular weight greater than or equal to 500 Daltons. Yet, another embodiment of this invention provides boehmite nanoparticles that are surface modified with two or more acids one of which is hydrophobic in nature and has solubility in water of less than 15 by weight. The products of the methods of this invention have specific useful properties when used in mixture with liquids, as filler in solids, or as stand-alone entities.

Fabrication of polyaniline-HCl cladding modified fiber optic intrinsic biosensor for glucose detection

NASA Astrophysics Data System (ADS)

Pahurkar, Vikas; Tamgadge, Yuoraj; Muley, Gajanan

2016-05-01

In the present study, we have fabricated and studied response of cladding modified fiber optic intrinsic glucose biosensor (FOIGB). The optical fiber was used as a light transforming waveguide and sensing element fabricated over it by applying a thin layer of polymer. The cladding of the sensor was modified with the polyaniline-hydrochloric acid (PANI-HCl) polymer matrix. The PANI-HCl matrix provides an amorphous morphology useful to immobilize glucose oxidase (GOx) biomolecules through cross-linking technique via glutaraldehyde. The present sensor was used to detect the glucose analyte in the solution. In the sensing response study of FOIGB toward glucose, novel modal power distribution (MPD) technique was used. The reaction between GOx and glucose changes the optical properties of prepared FOIGB and hence modify MPD at output as a function of glucose concentration. The nature and surface morphology of PANI-HCl matrix has been studied.

Synthesis, characterization and low temperature electrical conductivity of Polyaniline/NiFe2O4 nanocomposites

NASA Astrophysics Data System (ADS)

Prasanna, G. D.; Prasad, V. B.; Jayanna, H. S.

2015-02-01

Conducting polymer/ferrite nanocomposites with an organized structure provide a new functional hybrid between organic and inorganic materials. The most popular among the conductive polymers is the polyaniline (PANI) due to its wide application in different fields. In the present work nickel ferrite (NiFe2O4) nanoparticles were prepared by sol-gel citrate-nitrate method with an average size of 21.6nm. PANI/NiFe2O4 nanoparticles were synthesized by a simple general and inexpensive in-situ polymerization in the presence of NiFe2O4 nanoparticles. The effects of NiFe2O4 nanoparticles on the dc-electrical properties of polyaniline were investigated. The structural components in the nanocomposites were identified from Fourier Transform Infrared (FTIR) spectroscopy. The crystalline phase of nanocomposites was characterized by X-Ray Diffraction (XRD). The Scanning Electron Micrograph (SEM) reveals that there was some interaction between the NiFe2O4 particles and polyaniline and the nanocomposites are composed of polycrystalline ferrite nanoparticles and PANI. The dc conductivity of polyaniline/NiFe2O4 nanocomposites have been measured as a function of temperature in the range of 80K to 300K. It is observed that the room temperature conductivity cRT decreases with increase in the relative content of NiFe2O4. The experimental data reveals that the resistivity increases for all composites with decrease of temperature exhibiting semiconductor behaviour.

Assessment of polyaniline nanoparticles toxicity and teratogenicity in aquatic environment using Rhinella arenarum model.

PubMed

Ibarra, Luis E; Tarres, Lucrecia; Bongiovanni, Silvestre; Barbero, César A; Kogan, Marcelo J; Rivarola, Viviana A; Bertuzzi, Mabel L; Yslas, Edith I

2015-04-01

With the rapid growth of nanotechnology and the applications of nanoparticles, environmental exposure to these particles is increasing. However, their impact in human and environmental health is not well studied. Anurans, with life stage comprising embryos, tadpoles and adults, have an extremely permeable skin which makes them excellent indicators of environmental health. This study evaluated the acute toxicity effects of polyaniline nanoparticles (PANI-Np) in different dispersant on embryos and larvae of Rhinella arenarum. The results showed that LC50 of PANI-Np dispersed in polyvinylpyrrolidone (PVP) were 1,500 mg/L, while LC50 by PANI-Np dispersed in PVP+PNIPAM (polyN-isopropylacrilamide) showed a highest toxicity (1,170 mg/L). The embryo teratogenicity increased with increasing exposure concentration in both kinds of PANI-Np although in PANI-Np1, there is an increased teratogenic effect associated with the polymer stabilizer PVP. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis and characterization of conducting polyaniline-copper composites.

PubMed

Liu, Aijie; Bac, Luong Huu; Kim, Ji-Soon; Kim, Byoung-Kee; Kim, Jin-Chun

2013-11-01

Conducting polymer composites have many interesting physical properties and important application potentials. Suitable combinations of metal nanoparticles with conductive polymers can result in composite materials having unique physical and chemical properties that can have wide application potential in diverse areas. In this work, copper nanoparticles were fabricated by electrical explosion of wire (EEW) in solution of polyacrylic acid (PAA) and ethanol. Conductive polyaniline-copper (PANI-Cu) composites have been synthesized by in-situ polymerization of aniline in the fabricated copper suspension. Optical absorption in the UV-visible region of these suspensions was measured in the range of 200-900 nm. Morphology and structure of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR). Pure copper nanoparticles were uniformly dispersed into the polymer matrix. Thermal stability of the composites was characterized by thermogravimetric analysis (TGA). Electrical conductivity measurements indicated that the conductivity of the composites was higher than that of pure polyaniline and increased with increasing content of copper.

Immobilization of biomolecules on cysteamine-modified polyaniline film for highly sensitive biosensing.

PubMed

Cai, Qi; Xu, Baojian; Ye, Lin; Di, Zengfeng; Zhang, Jishen; Jin, Qinghui; Zhao, Jianlong; Xue, Jian; Chen, Xianfeng

2014-03-01

We present a new cysteamine (CS)-modified polyaniline (PANI) film for highly efficient immobilization of biomolecules in biosensing technology. This electrochemical deposited PANI film treated with CS and glutaraldehyde could be employed as an excellent substrate for biomolecules immobilization. The parameters of PANI growth were optimized to obtain suitable surface morphology of films for biomolecules combination with the help of electron and atomic force microscopy. Cyclic voltammetry (CV) was utilized to illustrate the different electrochemical activities of each modified electrode. Due to the existence of sulfydryl group and amino group in CS, surface modification with CS was proven to reduce oxidized units on PANI film remarkably, as evidenced by both ATR-FTIR and Raman spectroscopy characterizations. Furthermore, bovine serum albumin (BSA) was used as the model protein to investigate the immobilization efficiency of biomolecules on the PANI film, comparative study using quartz crystal microbalance (QCM) showed that BSA immobilized on CS-modified PANI could be increased by at least 20% than that without CS-modified PANI in BSA solution with the concentration of 0.1-1mg/mL. The CS-modified PANI film would be significant for the immobilization and detection of biomolecules and especially promising in the application of immunosensor for ultrasensitive detection. © 2013 Published by Elsevier B.V.

Magnetoconductive maghemite core/polyaniline shell nanoparticles: Physico-chemical and biological assessment.

PubMed

Anna, Zasońska Beata; Patrycja, Bober; Petr, Jošt; Petrovský, Eduard; Pavel, Boštík; Daniel, Horák

2016-05-01

Nanoparticles of various compositions are increasingly being used in many areas of medicine. The aim of this study was to develop nanoparticles, which would possess both magnetic and conductive properties and, thus improve their suitability for a wider range of biomedical applications. Namely, it would enable both the particle manipulation and imaging using their magnetic properties and simultaneous stimulation of electro-sensitive cell types using their magnetic properties, which can be used in tissue therapy, engineering and as biosensors. Maghemite (γ-Fe2O3) particles were prepared by the co-precipitation of Fe(2+) and Fe(3+) salts with ammonium hydroxide, followed by the controlled oxidation with NaOCl. The polyaniline (PANI) shell on the γ-Fe2O3 nanoparticles was obtained by the polymerization of aniline hydrochloride with ammonium peroxydisulfate in an aqueous solution of poly(N-vinylpyrrolidone) at two reaction temperatures (0 and 25 °C). The resulting γ-Fe2O3&PANI particles were characterized by both the light and transmission electron microscopies, dynamic light scattering, magnetic measurements, UV-vis and energy dispersive X-ray (EDAX) spectroscopy. The size of the starting γ-Fe2O3 particles was 11 nm, that increased to 25 nm after the modification with PANI. The incubation of both the γ-Fe2O3 and γ-Fe2O3&PANI nanoparticles with the human neuroblastoma derived SH-SY5Y cells for 8 days showed neither significant decrease in the cell viability, nor detectable changes in the cell morphology. This indicates, that the particles have no detectable cytotoxicity in cell culture and represent a promising tool for further use in biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel H(2)O(2) amperometric biosensor based on gold nanoparticles/self-doped polyaniline nanofibers.

PubMed

Chen, Xiaojun; Chen, Zixuan; Zhu, Jinwei; Xu, Chenbin; Yan, Wei; Yao, Cheng

2011-10-01

A new kind of gold nanoparticles/self-doped polyaniline nanofibers (Au/SPAN) with grooves has been prepared for the immobilization of horseradish peroxidase (HRP) on the surface of glassy carbon electrode (GCE). The ratio of gold in the composite nanofibers was up to 64%, which could promote the conductivity and biocompatibility of SPAN and increase the immobilized amount of HRP molecules greatly. The electrode exhibits enhanced electrocatalytic activity in the reduction of H(2)O(2) in the presence of the mediator hydroquinone (HQ). The effects of concentration of HQ, solution pH and the working potential on the current response of the modified electrode toward H(2)O(2) were optimized to obtain the maximal sensitivity. The proposed biosensor exhibited a good linear response in the range from 10 to 2000 μM with a detection limit of 1.6 μM (S/N=3) under the optimum conditions. The response showed Michaelis-Menten behavior at larger H(2)O(2) concentrations, and the apparent Michaelis-Menten constant K(m) was estimated to be 2.21 mM. The detection of H(2)O(2) concentration in real sample showed acceptable accuracy with the traditional potassium permanganate titration. Copyright © 2011 Elsevier B.V. All rights reserved.

An impedimetric biosensor for detection of dengue serotype at picomolar concentration based on gold nanoparticles-polyaniline hybrid composites.

PubMed

Nascimento, Helena P O; Oliveira, Maria D L; de Melo, Celso P; Silva, Gilcelia J L; Cordeiro, Marli T; Andrade, Cesar A S

2011-09-01

In this work, we describe the preparation and characterization of a novel gold nanoparticles-polyaniline hybrid composite (AuNpPANI) with SH-terminal groups that, due to its ability of immobilizing dengue serotype-specific primers 1, 2 and 3 (ST1, ST2 and ST3), can be used for the development of biosensors. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were performed. CV and EIS results demonstrated that the AuNpPANI can immobilize ST1, ST2 and ST3, forming AuNpPANI-ST complexes. Well-defined cyclic voltammograms characteristic of a diffusion-limited redox process were observed both for the bare gold electrode and after these electrodes have been modified by the adsorption of AuNpPANI or AuNpPANI-ST. The AuNpPANI-ST(1-3) systems were able to recognize the dengue serotype of different patients at picomolar concentrations. Even when small volumes and low concentrations of the analyte were used, the CV and EIS results showed unequivocal evidence of an existing interaction between dengue serotype-specific primers and their complementary genomic DNA targets. Copyright © 2011 Elsevier B.V. All rights reserved.

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Siloxane modified silica nanoparticles... Specific Chemical Substances § 721.10119 Siloxane modified silica nanoparticles (generic). (a) Chemical... as siloxane modified silica nanoparticles (PMN P-05-673) is subject to reporting under this section...

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Siloxane modified silica nanoparticles... Specific Chemical Substances § 721.10119 Siloxane modified silica nanoparticles (generic). (a) Chemical... as siloxane modified silica nanoparticles (PMN P-05-673) is subject to reporting under this section...

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Siloxane modified silica nanoparticles... Specific Chemical Substances § 721.10119 Siloxane modified silica nanoparticles (generic). (a) Chemical... as siloxane modified silica nanoparticles (PMN P-05-673) is subject to reporting under this section...

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Siloxane modified silica nanoparticles... Specific Chemical Substances § 721.10119 Siloxane modified silica nanoparticles (generic). (a) Chemical... as siloxane modified silica nanoparticles (PMN P-05-673) is subject to reporting under this section...

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Siloxane modified silica nanoparticles... Specific Chemical Substances § 721.10119 Siloxane modified silica nanoparticles (generic). (a) Chemical... as siloxane modified silica nanoparticles (PMN P-05-673) is subject to reporting under this section...

Accelerating the design of molecularly imprinted nanocomposite membranes modified by Au@polyaniline for selective enrichment and separation of ibuprofen

NASA Astrophysics Data System (ADS)

Wu, Xiuling; Wu, Yilin; Dong, Hongjun; Zhao, Juan; Wang, Chen; Zhou, Shi; Lu, Jian; Yan, Yongsheng; Li, He

2018-01-01

A novel system for harvesting molecularly imprinted nanocomposite membranes (MINcMs) with Au-modified polyaniline (Au@polyaniline) nanocomposite structure was developed for selective enrichment and separation of ibuprofen. This unique nanocomposite structure obviously enhanced the adsorption capacity, perm-selectivity performance, and regeneration ability of MINcMs. The as-prepared MINcMs showed outstanding adsorption capacity (22.02 mg g-1) of ibuprofen, which was four times higher than that of non-imprinted nanocomposite membranes (NINcMs). Furthermore, the selectivity factor of MINcMs for ibuprofen reached up to 4.67 and the perm-selectivity factor β was about 8.74, which indicated MINcMs had a good selective separation performance of ibuprofen. We envision that this novel synthesis method will open a new direction to manipulation of molecularly imprinted membrane materials and provide a simple yet convenient way to selective separation of ibuprofen.

Nanocomposites of natural rubber and polyaniline-modified cellulose nanofibrils

USDA-ARS?s Scientific Manuscript database

Cellulose nanofibrils (CNF) were isolated from cotton microfibrils (CM) by acid hydrolysis and coated with polyaniline (PANI) by in situ polymerization of aniline onto CNF in the presence of hydrochloride acid and ammonium peroxydisulfate to produce CNF/PANI. Nanocomposites of natural rubber (NR) re...

Spectral imaging method for studying Physarum polycephalum growth on polyaniline surface.

PubMed

Dimonte, A; Fermi, F; Berzina, T; Erokhin, V

2015-08-01

The features of spectrophotometric scanner, generally exploited in the artwork field, are here considered in a non-conventional context to characterize the networks created by Physarum polycephalum slime mold during its motion on glass substrates covered with polyaniline: a polymer that varies its color and conductive properties according to the redox state. The used technique allowed the investigation of the effects coming out from the interaction between P. polycephalum and polyaniline. Thus, the contactless method of the analysis of polyaniline conductivity state resulted from the slime mold metabolism was suggested. Indeed, it is here demonstrated that P. polycephalum can modify properties of polyaniline due to its internal activity in contact zones. Copyright © 2015. Published by Elsevier B.V.

A Facile Synthesis of a Palladium-Doped Polyaniline-Modified Carbon Nanotube Composites for Supercapacitors

NASA Astrophysics Data System (ADS)

Giri, Soumen; Ghosh, Debasis; Malas, Asish; Das, Chapal Kumar

2013-08-01

Supercapacitors have evolved as the premier choice of the era for storing huge amounts of charge in the field of energy storage devices, but it is still necessary to enhance their performance to meet the increasing requirements of future systems. This could be achieved either through advancing the interfaces of the material at the nanoscale or by using novel material compositions. We report a high-performance material composition prepared by combining a transition metal (palladium)-doped conductive polymer with multiwalled carbon nanotubes (MWCNTs). MWCNTs/palladium-doped polyaniline (MWCNTs/Pd/PANI) composites and multiwalled carbon nanotube/polyaniline (MWCNTs/PANI) composites (for comparison) were prepared via in situ oxidative polymerization of aniline monomer. The reported composites were characterized by Fourier-transform infrared (FTIR), x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) studies. FESEM and TEM studies indicated the narrow size distribution of the π-conjugated polymer-protected palladium nanoparticles on the surface of the carbon nanotubes. All the electrochemical characterizations were executed using a three-electrode system in 1 M H2SO4 electrolyte. Cyclic voltammetry (CV) analysis was performed to observe the capacitive performance and redox behavior of the composites. The ion transfer behavior and cyclic stability of the composites were investigated by electrochemical impedance spectroscopy (EIS) analysis and cyclic charge-discharge (CCD) testing, respectively. The MWCNTs/Pd/PANI composite was found to exhibit an especially high specific capacitance value of 920 F/g at scan rate of 2 mV/s.

Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

NASA Astrophysics Data System (ADS)

V, Mini; Kamath, Archana; S, Raghu; Chapi, Sharanappa; H, Devendrappa

2015-06-01

A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott's parameters show 3D -VRH Type conduction in it.

Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

PubMed

He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

2017-12-09

Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

Optical band gap tuning and electrical properties of polyaniline and its nanocomposites for hybrid solar cell application

NASA Astrophysics Data System (ADS)

Singh, R.; Choudhary, R. B.; Kandulna, R.

2018-05-01

Hcl doped conducting polyaniline-CdS nanocomposite has been prepared via In-situ polymerization in which cadmium nitrate was used as a source for cadmium. The structural morphology was investigated using FESEM and the presence of fibrous polyaniline and CdS nanoparticles. The synthesis of CdS and polyaniline was confirmed using the XRD analysis. I-V characteristic was used to explore the electrical behavior of PANI and its nanocoposites. Optical properties were studied and minimum band gap with highest band absorbance was found for synergistic concentration PANI-CdS (10%) for solar cells application.

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this section...

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this section...

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this section...

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this section...

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this section...

Large enhanced dielectric permittivity in polyaniline passivated core-shell nano magnetic iron oxide by plasma polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joy, Lija K.; Sooraj, V.; Sethulakshmi, N.

2014-03-24

Commercial samples of Magnetite with size ranging from 25–30 nm were coated with polyaniline by using radio frequency plasma polymerization to achieve a core shell structure of magnetic nanoparticle (core)–Polyaniline (shell). High resolution transmission electron microscopy images confirm the core shell architecture of polyaniline coated iron oxide. The dielectric properties of the material were studied before and after plasma treatment. The polymer coated magnetite particles exhibited a large dielectric permittivity with respect to uncoated samples. The dielectric behavior was modeled using a Maxwell–Wagner capacitor model. A plausible mechanism for the enhancement of dielectric permittivity is proposed.

Synthesis and characterization of structural and magnetic properties of polyaniline-cobalt ferrite (PA-CoFe) nanocomposites

NASA Astrophysics Data System (ADS)

Thakur, Sonika; Kaur, Parminder; Singh, Lakhwant

2018-05-01

The growing interest in the investigation of the properties of modified conducting polymers stems from their potential applications in various fields such as in sensing and catalytic devices. The present work reports the modification of conducting polymer polyaniline with cobalt ferrite (CoFe) nanoparticles, where CoFe nanoparticles are added in different successive weight percents. The composite samples were synthesized by in-situ chemical oxidative polymerization technique. The density of the samples has been found to increase with an increase in the CoFe content. Structural analysis of the synthesized sample has been done using X-ray diffraction studies. Perusal of the hysteresis curves of the prepared samples depicts that the introduction of CoFe into the polymer matrix leads to enhancement in the ferromagnetic behavior of the synthesized samples, suggesting that these nanocomposites have excellent microwave absorbing capacity.

Polyaniline-Modified Oriented Graphene Hydrogel Film as the Free-Standing Electrode for Flexible Solid-State Supercapacitors.

PubMed

Du, Pengcheng; Liu, Huckleberry C; Yi, Chao; Wang, Kai; Gong, Xiong

2015-11-04

In this study, we report polyaniline (PANI)-modified oriented graphene hydrogel (OGH) films as the free-standing electrode for flexible solid-state supercapacitors (SCs). The OGH films are prepared by a facile filtration method using chemically converted graphene sheets and then introduced to PANI on the surface of OGH films by in situ chemical polymerization. The PANI-modified OGH films possess high flexibility, high electrical conductivity, and mechanical robustness. The flexible solid-state SCs based on the PANI-modified OGH films exhibit a specific capacitance of 530 F/g, keeping 80% of its original value up to 10 000 charge-discharge cycles at the current density of 10 A/g. Remarkably, the flexible solid-state SCs maintain ∼100% capacitance retention bent at 180° for 250 cycles. Moreover, the flexible solid-state SCs are further demonstrated to be able to light up a red-light-emitting diode. These results indicate that the flexible solid-state SCs based on PANI-modified OGH films as the free-standing electrode have potential applications as energy-storage devices.

Synthesis of Fe nanoparticles on polyaniline covered carbon nanotubes for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Hu, Tian-Hang; Yin, Zhong-Shu; Guo, Jian-Wei; Wang, Cheng

2014-12-01

Fe nanoparticles immobilized on polyaniline-covered carbon nanotube (CNT) surfaces (Fe NPs-PANI/CNT) are prepared by reducing FeCl3 in the mixing solution of aniline and CNT. Significantly, the structure of such composites can be effectively optimized by pretreating FeCl3 with sodium citrate (CA). In the absence of CNTs, we found these two routes have large differences in reduction behaviors and different PANI states with varied conductivities. Therefore, the self-assembly mechanism in the preparation is proposed and the controlled self-assembly manner in the pretreating route is disclosed. Under acid condition, both catalysts demonstrate high oxygen reduction reaction (ORR) activity with four-electron pathway, and high electrochemical durability, revealing a promising application in the proton exchange membrane fuel cells. However, the high Tafel slopes relating to the surface red-ox couple and porous conductivity are still the main obstacles to improve their ORR dynamic, and more efforts on these aspects are needed to drive non-noble catalyst application in future.

Composite nanofibers prepared from metallic iron nanoparticles and polyaniline: high performance for water treatment applications.

PubMed

Bhaumik, Madhumita; Choi, Hyoung J; McCrindle, Rob I; Maity, Arjun

2014-07-01

Presented here is a simple preparation of metallic iron nanoparticles, supported on polyaniline nanofibers at room temperature. The preparation is based on polymerization of interconnected nanofibers by rapid mixing of the aniline monomer with Fe(III) chloride as the oxidant, followed by reductive deposition of Fe(0) nanoparticles, using the polymerization by-products as the Fe precursor. The morphology and other physico-chemical properties of the resulting composite were characterized by scanning and transmission electron microscopy, Brunauer-Emmett-Teller method, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and vibrating-sample magnetometry. The composite fibers were 80-150 nm in diameter and exhibited the expected ferromagnetic behavior. The composite rapidly and efficiently removed As(V), Cr(VI), and also Congo red dye, from aqueous solutions suggesting their usefulness for removal of toxic materials from wastewater. The composite fibers have high capacity for toxin removal: 42.37 mg/g of As(V), 434.78 mg/g of Cr(VI), and 243.9 mg/g of Congo red. The fibers are easily recovered from fluids by exploiting their ferromagnetic properties. Copyright © 2014 Elsevier Inc. All rights reserved.

Combination of cathodic reduction with adsorption for accelerated removal of Cr(VI) through reticulated vitreous carbon electrodes modified with sulfuric acid-glycine co-doped polyaniline.

PubMed

Mo, Xi; Yang, Zhao-hui; Xu, Hai-yin; Zeng, Guang-ming; Huang, Jing; Yang, Xia; Song, Pei-pei; Wang, Li-ke

2015-04-09

Improving the reduction kinetics is crucial in the electroreduction process of Cr(VI). In this study, we developed a novel adsorption-electroreduction system for accelerated removal of Cr(VI) by employing reticulated vitreous carbon electrode modified with sulfuric acid-glycine co-doped polyaniline (RVC/PANI-SA-GLY). Firstly, response surface methodology confirmed the optimum polymerization condition of co-doped polyaniline for modifying electrodes (Aniline, sulfuric acid and glycine, respectively, of 0.2 mol/L, 0.85 mol/L, 0.93 mol/L) when untraditional dopant glycine was added. Subsequently, RVC/PANI-SA-GLY showed higher Cr(VI) removal percentages in electroreduction experiments over RVC electrode modified with sulfuric acid doped polyaniline (RVC/PANI-SA) and bare RVC electrode. In contrast to RVC/PANI-SA, the improvement by RVC/PANI-SA-GLY was more significant and especially obvious at more negative potential, lower initial Cr(VI) concentration, relatively less acidic solution and higher current densities, best achieving 7.84% higher removal efficiency with entire Cr(VI) eliminated after 900 s. Current efficiencies were likewise enhanced by RVC/PANI-SA-GLY under quite negative potentials. Fourier transform infrared (FTIR) and energy dispersive spectrometer (EDS) analysis revealed a possible adsorption-reduction mechanism of RVC/PANI-SA-GLY, which greatly contributed to the faster reduction kinetics and was probably relative to the absorption between protonated amine groups of glycine and HCrO4(-). Eventually, the stability of RVC/PANI-SA-GLY was proven relatively satisfactory. Copyright © 2015 Elsevier B.V. All rights reserved.

Gelatin modified lipid nanoparticles for anti- viral drug delivery.

PubMed

K S, Joshy; S, Snigdha; Kalarikkal, Nandakumar; Pothen, Laly A; Thomas, Sabu

2017-10-01

The major challenges to clinical application of zidovudine are its moderate aqueous solubility and relative short half-life and serious side effects due to frequent administrations. We investigated the preparation of zidovudine-loaded nanoparticles based on lipids which were further modified with the polymer gelatin. Formulation and stability of the modified nanoparticles were analysed from the physico-chemical characterizations. The interactions of nanoparticles with blood components were tested by haemolysis and aggregation studies. The drug content and entrapment efficiencies were assessed by UV analysis. The effect of nanoparticles on protein adsorption was assessed by native polyacrylamide gel electrophoresis (PAGE). In vitro release studies showed a sustained release profile of zidovudine. In vitro cytotoxicity and cellular uptake of the zidovudine-loaded nanoparticles were performed in MCF-7 and neuro 2a brain cells. The enhanced cellular internalization of drug loaded modified nanoparticles in both the cell lines were revealed by fluorescence microscopy. Hence the present study focuses on the feasibility of zidovudine-loaded polymer modified lipid nanoparticles as carriers for safe and efficient HIV/AIDS therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Tollen’s reagent assisted synthesis of hollow polyaniline microsphere/Ag nanocomposite and its applications in sugar sensing and electromagnetic shielding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panigrahi, R.; Srivastava, S.K., E-mail: sunit@chem.iitkgp.ernet.in

Graphical abstract: Probable scheme to demonstrate the mechanism of PnHMAg showing enhanced EMI shielding compared to PnHM. - Highlights: • Hollow polyaniline microsphere (PnHM) exhibits superior properties due to its enhanced surface to volume ratio. • PnHMAg has been used in developing efficient sensor for the detection of sugar. • Presence of Ag nanoparticles enhances the electrical conductivity of PnHMAg resulting in the improvement of electromagnetic interference shielding in both X- and S-band regions. • Such properties could be harnessed effectively for development of devices for commercial as well as national purposes. - Abstract: The present study is focused onmore » synthesis of polyaniline hollow microspheres (PnHM) nanocomposites of silver (Ag) i.e., PnHMAg by emulsion polymerization of aniline and Tollen’s reagent as a source for Ag nanoparticles. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis of PnHMAg indicated presence of silver nanoparticles dispersed on polyaniline surface. The electrical conductivity of PnHMAg is increased by ∼6 times compared to PnHM. Cyclic voltammogram of PnHM in sugar sensing exhibits characteristics redox peaks at ∼0.09 (sugar) and ∼0.53 V (polyaniline). Interestingly, PnHMAg showed a single peak at ∼−0.18 V with increased intensity (∼5 times) indicating its high sugar sensing ability. PnHMAg also exhibits high shielding efficiency of 19.5 dB (11.2 GHz) due to the presence of highly conducting Ag nanoparticles. TEM studies confirmed that Ag nanoparticles are well distributed on PnHM. As a result, a continuous electronic path is developed due to enhanced interconnectivity of PnHM.« less

In situ polymerization of polyaniline in wood veneers.

PubMed

Trey, Stacy; Jafarzadeh, Shadi; Johansson, Mats

2012-03-01

The present study describes the possibility to polymerize aniline within wood veneers to obtain a semi-conducting material with solid wood acting as the base template. It was determined that it is possible to synthesize the intrinsically conductive polymer (ICP) polyaniline in situ within the wood structure of Southern yellow pine veneers, combining the strength of the natural wood structure with the conductivity of the impregnated polymer. It was found that polyaniline is uniformly dispersed within the wood structure by light microscopy and FT-IR imaging. A weight percent gain in the range of 3-12 wt % was obtained with a preferential formation in the wood structure and cell wall, rather than in the lumen. The modified wood was found to be less hydrophilic with the addition of phosphate doped polyaniline as observed by equilibrium water swelling studies. While wood itself is insulating, the modified veneers had conductivities of 1 × 10(-4) to 1 × 10(-9) S cm(-1), demonstrating the ability to tune the conductivity and allowing for materials with a wide range of applications, from anti-static to charge-dispersing materials. Furthermore, the modified veneers had lower total and peak heat releases, as determined by cone calorimetry, because of the char properties of the ICP. This is of interest if these materials are to be used in building and furniture applications where flame retardance is of importance. © 2012 American Chemical Society

Oxidation and sensing of ascorbic acid and dopamine on self-assembled gold nanoparticles incorporated within polyaniline film

NASA Astrophysics Data System (ADS)

Chu, Wenya; Zhou, Qun; Li, Shuangshuang; Zhao, Wei; Li, Na; Zheng, Junwei

2015-10-01

Electrochemical biosensors based on conducting polymers incorporated with metallic nanoparticles can greatly enhance sensitivity and selectivity. Herein, we report a facile fabrication approach for polyaniline (PAN) incorporated with a gold nanoparticle (AuNP) composite electrode by electrodeposition of PAN on a self-assembled AuNP layer on the surface of an indium tin oxide electrode. The resulting AuNP/PAN composite electrode exhibits a remarkable synergistic effect on the electrocatalytic oxidation of ascorbic acid (AA) and dopamine (DA). It is demonstrated that the oxidation reaction of AA mainly occurs at AuNPs inside the PAN film as the ascorbate anions are doped into the polymer during the oxidation of the PAN film. Conversely, the oxidation of positively charged DA may only take place at the PAN/solution interface. The different mechanisms of the electrode reactions result in the oxidation of AA and DA occurring at different potentials. As a result, the AuNP/PAN composite electrode can be employed to simultaneously detect AA and DA with a good linear range, high sensitivity, and low detection limit.

Ammonia gas sensing behavior of tanninsulfonic acid doped polyaniline-TiO₂ composite.

PubMed

Bairi, Venu Gopal; Bourdo, Shawn E; Sacre, Nicolas; Nair, Dev; Berry, Brian C; Biris, Alexandru S; Viswanathan, Tito

2015-10-16

A highly active tannin doped polyaniline-TiO₂ composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO₂ in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO₂. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO₂ and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO₂ composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

Enhanced structural and optical properties of the polyaniline-calcium tungstate (PANI-CaWO4 nanocomposite for electronics applications

NASA Astrophysics Data System (ADS)

Sabu, N. Aloysius; Francis, Xavier; Anjaly, Jose; Sankararaman, S.; Varghese, Thomas

2017-06-01

In this article, we report the synthesis and characterization of polyaniline-calcium tungstate nanocomposite, a novel material for potential applications. The PANI-CaWO4 nanocomposite was prepared by in situ oxidative polymerization of aniline in the presence of CaWO4 nanoparticles dispersed in ethanol. Investigations using X-ray diffraction, Fourier-transformed infrared spectroscopy, UV-visible, photoluminescence and Raman spectroscopy confirmed the formation of the nanocomposite of PANI with CaWO4 nanoparticles. Scanning electron microscopy revealed almost uniform distribution of CaWO4 nanoparticles in the polyaniline matrix. These studies also confirmed electronic structure modification as a result of incorporating CaWO4 nanoparticles in PANI. Composite formation resulted in large decrease in the optical band gap and enhanced photoluminescence. The augmented structural, optical and photoluminescence properties of the PANI-CaWO4 nanocomposite can be used to explore potential applications in micro- and optoelectronics. This is the first report presenting synthesis and characterization of the PANI-CaWO4 nanocomposite.

Prevention of corrosion with polyaniline

NASA Technical Reports Server (NTRS)

Ahmad, Naseer (Inventor); MacDiarmid, Alan G. (Inventor)

1997-01-01

Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating.

Oral Delivery of DMAB-Modified Docetaxel-Loaded PLGA-TPGS Nanoparticles for Cancer Chemotherapy

NASA Astrophysics Data System (ADS)

Chen, Hongbo; Zheng, Yi; Tian, Ge; Tian, Yan; Zeng, Xiaowei; Liu, Gan; Liu, Kexin; Li, Lei; Li, Zhen; Mei, Lin; Huang, Laiqiang

2011-12-01

Three types of nanoparticle formulation from biodegradable PLGA-TPGS random copolymer were developed in this research for oral administration of anticancer drugs, which include DMAB-modified PLGA nanoparticles, unmodified PLGA-TPGS nanoparticles and DMAB-modified PLGA-TPGS nanoparticles. Firstly, the PLGA-TPGS random copolymer was synthesized and characterized. DMAB was used to increase retention time at the cell surface, thus increasing the chances of particle uptake and improving oral drug bioavailability. Nanoparticles were found to be of spherical shape with an average particle diameter of around 250 nm. The surface charge of PLGA-TPGS nanoparticles was changed to positive after DMAB modification. The results also showed that the DMAB-modified PLGA-TPGS nanoparticles have significantly higher level of the cellular uptake than that of DMAB-modified PLGA nanoparticles and unmodified PLGA-TPGS nanoparticles. In vitro, cytotoxicity experiment showed advantages of the DMAB-modified PLGA-TPGS nanoparticle formulation over commercial Taxotere® in terms of cytotoxicity against MCF-7 cells. In conclusion, oral chemotherapy by DMAB-modified PLGA-TPGS nanoparticle formulation is an attractive and promising treatment option for patients.

Facile synthesis of polyaniline-modified CuS with enhanced adsorbtion and photocatalytic activity

NASA Astrophysics Data System (ADS)

Wang, Xiufang; Chen, Shaohua; Shuai, Ying

2016-10-01

Novel hierarchical polyaniline-modified CuS (PANI-CuS) has been synthesized by simple assembling PANI on the surface of flower-like CuS spheres. The PANI modification enhances the adsorption properties of flower-like CuS. The prepared PANI-CuS composites exhibit higher visible-light-driven photocatalytic activities in degradation of rhodamine B (RhB) than that of neat CuS. The unusual photocatalytic activity could be attributed to the great adsorptivity of dyes, the extended photoresponse range, and the high migration efficiency of photoinduced electrons, which may effectively suppress the charge recombination. This work not only provides a simple strategy for fabricating highly efficient and stable CuS-based composites, but also proves that these unique structures are excellent platforms for significantly improving their visible- light-driven photoactivities, holding great promise for their applications in the field of purifying polluted water resources.

Development of amperometric lysine biosensors based on Au nanoparticles/multiwalled carbon nanotubes/polymers modified Au electrodes.

PubMed

Chauhan, Nidhi; Singh, Anamika; Narang, Jagriti; Dahiya, Swati; Pundir, C S

2012-11-07

The construction of two amperometric l-lysine biosensors is described in this study. The construction comprises the covalent immobilization of lysine oxidase (LOx) onto nanocomposite composed of gold nanoparticles (AuNPs) and carboxylated multiwalled carbon nanotubes (c-MWCNT), decorated on (i) polyaniline (PANI) and (ii) poly 1,2 diaminobenzene (DAB), electrodeposited on Au electrodes. The biosensors were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and electrochemical impedance spectroscopy (EIS) studies. The optimum response (current) was observed within 2 s at pH 7.0 and 25 °C for LOx/AuNPs/c-MWCNT/PANI/Au, and 4 s at pH 7.0 and 30 °C for LOx/AuNPs/c-MWCNT/DAB/Au electrodes. There was a linear relationship between current and lysine concentration ranging from 5.0 to 600 μM for LOx/AuNPs/c-MWCNT/PANI/Au with a detection limit of 5.0 μM, and 20 to 600 μM for the LOx/AuNPs/c-MWCNT/DAB/Au electrode with a detection limit of 20 μM. The PANI modified electrode was in good agreement with the standard HPLC method, with a better correlation (r = 0.992) compared to the DAB modified electrode (r = 0.986). These observations revealed that the PANI modified Au electrode was better than the DAB modified electrode, and hence it was employed for the determination of lysine in milk, pharmaceutical tablets and sera. The PANI modified electrode showed a half life of 120 days, compared to that of 90 days for the DAB modified electrode, after their 100 uses, when stored at 4 °C.

Investigation of follicular and non-follicular pathways for polyarginine and oleic acid modified nanoparticles

PubMed Central

Hayden, Patrick; Singh, Mandip

2013-01-01

Purpose The aim of the current study was to investigate the percutaneous permeation pathways of cell penetrating peptide modified lipid nanoparticles and oleic acid modified polymeric nanoparticles. Methods Confocal microscopy was performed on skin cultures (EpiDermFT™) for modified and un-modified nanoparticles. Differential stripping was performed following in vitro skin permeation of Ibuprofen (Ibu) encapsulated nanoparticles to estimate Ibu levels in different skin layers and receiver compartment. The hair follicles (HF) were blocked and in vitro skin permeation of nanoparticles was then compared with unblocked HF. The surface modified nanoparticles were investigated for response on allergic contact dermatitis (ACD). Results Surface modified nanoparticles showed a significant higher (p < 0.05) in fluorescence in EpiDermFT™ cultures compared to controls. The HF play less than 5% role in total nanoparticle permeation into the skin. The Ibu levels were significantly high (p<0.05) for surface modified nanoparticles compared to controls. The Ibu levels in skin and receiver compartment were not significantly different when HF were open or closed. Modified nanoparticles showed significant improvement in treatment of ACD compared to solution. Conclusions Our studies demonstrate that increased skin permeation of surface modified nanoparticles is not only dependent on a follicular pathway but also occur through non-follicular pathway(s). PMID:23187866

Polyaniline (PANI) modified bentonite by plasma technique for U(VI) removal from aqueous solution

NASA Astrophysics Data System (ADS)

Liu, Xinghao; Cheng, Cheng; Xiao, Chengjian; Shao, Dadong; Xu, Zimu; Wang, Jiaquan; Hu, Shuheng; Li, Xiaolong; Wang, Weijuan

2017-07-01

Polyaniline (PANI) modified bentonite (PANI/bentonie) was synthesized by plasma induced polymerization of aniline on bentonite surface, and applied to uptake of uranium(VI) ions from aqueous solution. The as-synthesized PANI/bentonie was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Batch adsorption technique was utilized to investigate the adsorption of U(VI) on bentonite and PANI/bentonite. The adsorption of U(VI) (10 mg/L) on PANI/bentonite surface is fairly depend on solution pH, ionic strength, and temperature in solution. The modified PANI on PANI/bentonite surface significantly enhances its adsorption capability for U(VI). The presence of humic acid (HA) can sound enhance U(VI) adsorption on PANI/bentonite at pH < 6.5 because of the strong complexation, and inhibits U(VI) adsorption at pH > 6.5. According to the thermodynamic parameters, the adsorption of U(VI) on PANI/bentonite surface is a spontaneous and endothermic process. The results highlight the application of PANI/bentonite composites as candidate material for the uptake of trace U(VI) from aqueous solution.

Interfacial characterization and supercapacitive properties of polyaniline-Gum arabic nanocomposite/graphene oxide LbL modified electrodes

NASA Astrophysics Data System (ADS)

Oliveira, Rafaela D.; Santos, Cleverson S.; Ferreira, Rodolfo T.; Marciniuk, Gustavo; Marchesi, Luís F.; Garcia, Jarem R.; Vidotti, Marcio; Pessoa, Christiana A.

2017-12-01

In this manuscript, we describe the synthesis and electrochemical characterization of polyaniline-gum arabic nanocomposites and graphene oxide (PANI-GA/GO) modified electrodes with a detailed study concerning their supercapacitive properties. The electrode modification was carried out by using the Layer-by-Layer technique (LbL), where the PANI-GA nanocomposite dispersion was used as polycation and the GO colloidal dispersion as polyanion. The bilayer growth was followed by both UV-vis spectroscopy and cyclic voltammetry, and an increase in the characteristic PANI absorption and in the electrochemical signal was verified, confirming the electrode build up. Galvanostatic charge-discharge curves (GCDC) were performed to evaluate the supercapacitive properties of the modified electrodes, these results showed the dependence of the specific capacitance with the number of bilayers, where values of CS around 15 mF cm-2 (i = 0.1 mA cm-2) were found. Electrochemical impedance spectroscopy confirmed the pseudocapacitive properties of the modified electrodes, showing an increase in the low-frequency capacitance with the number of bilayers. Hereby the (PANI-GA/GO)-LbL electrodes were shown to be good candidates for active materials in supercapacitors.

Ammonia Gas Sensing Behavior of Tanninsulfonic Acid Doped Polyaniline-TiO2 Composite

PubMed Central

Bairi, Venu Gopal; Bourdo, Shawn E.; Sacre, Nicolas; Nair, Dev; Berry, Brian C.; Biris, Alexandru S.; Viswanathan, Tito

2015-01-01

A highly active tannin doped polyaniline-TiO2 composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO2 in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO2. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO2 and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO2 composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported. PMID:26501291

Stabilization of polyaniline solutions through additives

DOEpatents

Wrobleski, D.A.; Benicewicz, B.C.

1996-12-10

A stabilized non-conductive polyaniline solution comprising from about 1 to about 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution. 4 figs.

Stabilization of polyaniline solutions through additives

DOEpatents

Wrobleski, Debra A.; Benicewicz, Brian C.

1996-01-01

A stabilized non-conductive polyaniline solution comprising from about 1 to bout 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution.

Template-free electrochemical nanofabrication of polyaniline nanobrush and hybrid polyaniline with carbon nanohorns for supercapacitors.

PubMed

Wei, Di; Wang, Haolan; Hiralal, Pritesh; Andrew, Piers; Ryhänen, Tapani; Hayashi, Yasuhiko; Amaratunga, Gehan A J

2010-10-29

Polyaniline (PANI) nanobrushes were synthesized by template-free electrochemical galvanostatic methods. When the same method was applied to the carbon nanohorn (CNH) solution containing aniline monomers, a hybrid nanostructure containing PANI and CNHs was enabled after electropolymerization. This is the first report on the template-free method to make PANI nanobrushes and homogeneous hybrid soft matter (PANI) with carbon nanoparticles. Raman spectroscopy was used to analyze the interaction between CNH and PANI. Electrochemical nanofabrication offers simplicity and good control when used to make electronic devices. Both of these materials were applied in supercapacitors and an improvement capacitive current by using the hybrid material was observed.

Template-free electrochemical nanofabrication of polyaniline nanobrush and hybrid polyaniline with carbon nanohorns for supercapacitors

NASA Astrophysics Data System (ADS)

Wei, Di; Wang, Haolan; Hiralal, Pritesh; Andrew, Piers; Ryhänen, Tapani; Hayashi, Yasuhiko; Amaratunga, Gehan A. J.

2010-10-01

Polyaniline (PANI) nanobrushes were synthesized by template-free electrochemical galvanostatic methods. When the same method was applied to the carbon nanohorn (CNH) solution containing aniline monomers, a hybrid nanostructure containing PANI and CNHs was enabled after electropolymerization. This is the first report on the template-free method to make PANI nanobrushes and homogeneous hybrid soft matter (PANI) with carbon nanoparticles. Raman spectroscopy was used to analyze the interaction between CNH and PANI. Electrochemical nanofabrication offers simplicity and good control when used to make electronic devices. Both of these materials were applied in supercapacitors and an improvement capacitive current by using the hybrid material was observed.

Structure and properties of polyaniline nanocomposite coatings containing gold nanoparticles formed by low-energy electron beam deposition

NASA Astrophysics Data System (ADS)

Wang, Surui; Rogachev, A. A.; Yarmolenko, M. A.; Rogachev, A. V.; Xiaohong, Jiang; Gaur, M. S.; Luchnikov, P. A.; Galtseva, O. V.; Chizhik, S. A.

2018-01-01

Highly ordered conductive polyaniline (PANI) coatings containing gold nanoparticles were prepared by low-energy electron beam deposition method, with emeraldine base and chloroauric acid used as target materials. The molecular and chemical structure of the layers was studied by Fourier transform infrared, Raman, UV-vis and X-ray photoelectron spectroscopy. The morphology of the coatings was investigated by atomic force and transmission electron microscopy. Conductive properties were obtained by impedance spectroscopy method and scanning spreading resistance microscopy mode at the micro- and nanoscale. It was found that the emeraldine base layers formed from the products of electron-beam dispersion have extended, non-conductive polymer chains with partially reduced structure, with the ratio of imine and amine groups equal to 0.54. In case of electron-beam dispersion of the emeraldine base and chloroauric acid, a protoemeraldine structure is formed with conductivity 0.1 S/cm. The doping of this structure was carried out due to hydrochloric acid vapor and gold nanoparticles formed by decomposition of chloroauric acid, which have a narrow size distribution, with the most probable diameter about 40 nm. These gold nanoparticles improve the conductivity of the thin layers of PANI + Au composite, promoting intra- and intermolecular charge transfer of the PANI macromolecules aligned along the coating surface both at direct and alternating voltage. The proposed deposition method of highly oriented, conductive nanocomposite PANI-based coatings may be used in the direct formation of functional layers on conductive and non-conductive substrates.

Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

NASA Astrophysics Data System (ADS)

West, R. M.; Semancik, S.

2016-11-01

Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

Modifying sulfomethylated alkali lignin by horseradish peroxidase to improve the dispersibility and conductivity of polyaniline

NASA Astrophysics Data System (ADS)

Yang, Dongjie; Huang, Wenjing; Qiu, Xueqing; Lou, Hongming; Qian, Yong

2017-12-01

Pine and wheat straw alkali lignin (PAL and WAL) were sulfomethylated to improve water solubility, polymerized with horseradish peroxidase (HRP) to improve the molecular weight (Mw) and applied to dope and disperse polyaniline (PANI). The structural effect of lignin from different origins on the reactivities of sulfomethylation and HRP polymerization was investigated. The results show that WAL with less methoxyl groups and lower Mw have higher reactivity in sulfomethylation (SWAL). More phenolic hydroxyl groups and lower Mw benefit the HRP polymerization of sulfomethylated PAL (SPAL). Due to the natural three-dimensional aromatic structure and introduced sulfonic groups, SPAL and SWAL could effectively dope and disperse PANI in water by π-π stacking and electrostatic interaction. HRP modified SPAL (HRP-SPAL) with much higher sulfonation degree and larger Mw significantly increased the conductivity and dispersibility of lignin/PANI composites.

Photothermal and biodegradable polyaniline/porous silicon hybrid nanocomposites as drug carriers for combined chemo-photothermal therapy of cancer.

PubMed

Xia, Bing; Wang, Bin; Shi, Jisen; Zhang, Yu; Zhang, Qi; Chen, Zhenyu; Li, Jiachen

2017-03-15

To develop photothermal and biodegradable nanocarriers for combined chemo-photothermal therapy of cancer, polyaniline/porous silicon hybrid nanocomposites had been successfully fabricated via surface initiated polymerization of aniline onto porous silicon nanoparticles in our experiments. As-prepared polyaniline/porous silicon nanocomposites could be well dispersed in aqueous solution without any extra hydrophilic surface coatings, and showed a robust photothermal effect under near-infrared (NIR) laser irradiation. Especially, after an intravenous injection into mice, these biodegradable porous silicon-based nanocomposites as non-toxic agents could be completely cleared in body. Moreover, these polyaniline/porous silicon nanocomposites as drug carriers also exhibited an efficient loading and dual pH/NIR light-triggered release of doxorubicin hydrochloride (DOX, a model anticancer drug). Most importantly, assisted with NIR laser irradiation, polyaniline/PSiNPs nanocomposites with loading DOX showed a remarkable synergistic anticancer effect combining chemotherapy with photothermal therapy, whether in vitro or in vivo. Therefore, based on biodegradable PSiNPs-based nanocomposites, this combination approach of chemo-photothermal therapy would have enormous potential on clinical cancer treatments in the future. Considering the non-biodegradable nature and potential long-term toxicity concerns of photothermal nanoagents, it is of great interest and importance to develop biodegradable and photothermal nanoparticles with an excellent biocompatibility for their future clinical applications. In our experiments, we fabricated porous silicon-based hybrid nanocomposites via surface initiated polymerization of aniline, which showed an excellent photothermal effect, aqueous dispersibility, biodegradability and biocompatibility. Furthermore, after an efficient loading of DOX molecules, polyaniline/porous silicon nanocomposites exhibited the remarkable synergistic anticancer

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

NASA Astrophysics Data System (ADS)

Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

2013-02-01

Oral chemotherapy is a key step towards `chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

PubMed Central

2013-01-01

Oral chemotherapy is a key step towards ‘chemotherapy at home’, a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer. PMID:23394588

Study the structural and optical behaviour of polyaniline/ZrO2 nanocomposites

NASA Astrophysics Data System (ADS)

Sidhu, Gaganpreet Kaur; Kumar, Naresh; Kumar, Rajesh

2018-05-01

In nanoscience, hybrid material based on polymer and nanoparticles are of great interest because of much improved properties of components. Polymers are of enormous interest because of their various properties like flexibility, low weight and easy processing. Here, we studied the influence of ZrO2 nanoparticles on the structural and optical properties of Polyaniline (PANI). ZrO2 mixed with PANI, improve its structural and optical properties. XRD studies reveal that ZrO2 nanoparticles exist in the tetragonal phase in ZrO2/PANI nanocomposites. UV-Vis spectroscopic studies have been carried out to understand the presence of various energy levels and their involvement in absorbance of light. In PANI nanocomposites, aniline monomer attach with ZrO2 nanoparticles through p-p stacking interaction, Vander waal force and hydrogen bonding interaction.

Gold Nanoparticles Deposited Polyaniline-TiO2 Nanotube for Surface Plasmon Resonance Enhanced Photoelectrochemical Biosensing.

PubMed

Zhu, Jie; Huo, Xiaohe; Liu, Xiaoqiang; Ju, Huangxian

2016-01-13

A novel ternary composite composed of TiO2 nanotubes (TiONTs), polyaniline (PANI), and gold nanoparticles (GNPs) was prepared for photoelectrochemical (PEC) biosensing. PANI was initially coated on TiONTs with an oxidative polymerization method, and 12-phosphotungstic acid was then used as a highly localized photoactive reducing agent to deposit GNPs on TiONT-PANI. The morphology and composition of the composite were characterized by various spectroscopic and microscopic methods. Electrochemical impedance spectroscopy was also conducted to demonstrate the excellent electrical conductivity of the composite. A PEC biosensor was fabricated by immobilizing a mixture of lactate dehydrogenase and the composite onto ITO electrodes, which regenerated nicotinamide adenine dinucleotide (NAD(+)) to complete the enzymatic cycle and led to an improved method for PEC detection of lactate. Because of the surface plasmon resonance enhanced effect of GNPs, the electrochromic performance of PANI, and excellent conductivity and biocompatibility of the composite, this method showed a dynamic range of 0.5-210 μM, sensitivity of 0.0401 μA μM(-1), and a detection limit of 0.15 μM.

Efficient in situ synthetic routes of polyaniline/poly(vinyl alcohol)/TiO2 nanocomposites using gamma irradiation

NASA Astrophysics Data System (ADS)

Afify, T. A.; Ghazy, O. A.; Saleh, H. H.; Ali, Z. I.

2018-02-01

Gamma radiation was used to prepare nanocomposites based on polyaniline/titanium dioxide (PANI/TiO2) or polyaniline/poly (vinyl alcohol)/titanium dioxide (PANI/PVA/TiO2). It was found that PANI/TiO2 in the form of nanocomposite as shown by the UV/vis spectroscopy. This was through the appearance and shift of two absorption peaks at 340 and 598 nm. The SEM micrographs of the PANI/TiO2 nanocomposites showed a fibrous morphology before the treatment with HCl. The TiO2 nanoparticles are clearly seen to be precipitated on the PANI fibers and the morphology changed towards the sheets shape with highly distribution on PANI surface. The transmission electron microscopy (TEM) image confirms the fibrous shape of the PANI and spherical shape of TiO2 nanoparticles. The XRD study showed a several diffraction patterns of TiO2 nanoparticles confirming the PANI/TiO2 and PANI/PVA/TiO2 nanocomposites. The FT-IR analysis indicated that there is an interfacial interaction existed between the PANI and its inorganic counterpart of TiO2 nanoparticles. The dielectric constant of the PANI/PVA showed the lowest values and was increased by either doping with TiO2 or increasing irradiation dose.

Characterization of MWCNT/Nanoclay Binary Nanoparticles Modified Composites and Fatigue Performance Evaluation of Nanoclay Modified Fiber Reinforced Composites

DTIC Science & Technology

2014-04-21

modified with binary nanoparticles consist of multi-walled carbon nanotubes (MWCNTs) and nanoclays together. First, epoxy SC-15 resin was reinforced...modified with binary nanoparticles consist of multi-walled carbon nanotubes (MWCNTs) and nanoclays together. First, epoxy SC-15 resin was reinforced with...7 2.2.1 Carbon Nanotube

Fabrication, characterisation and voltammetric studies of gold amalgam nanoparticle modified electrodes.

PubMed

Welch, Christine M; Nekrassova, Olga; Dai, Xuan; Hyde, Michael E; Compton, Richard G

2004-09-20

The tabrication, characterisation, and electroanalytical application of gold and gold amalgam nanoparticles on glassy carbon electrodes is examined. Once the deposition parameters for gold nanoparticle electrodes were optimised, the analytical utility of the electrodes was examined in CrIII electroanalysis. It was found that gold nanoparticle modified (Au-NM) electrodes possess higher sensitivity than gold macroelectrodes. In addition, gold amalgam nanoparticle modified (AuHg-NM) electrodes were fabricated and characterised. The response of those electrodes was recorded in the presence of important environmental analytes (heavy metal cations). It was found AuHg-NM electrodes demonstrate a unique voltammetric behaviour and can be applied for electroanalysis when enhanced sensitivity is crucial.

Anthelmintic activity of silver-extract nanoparticles synthesized from the combination of silver nanoparticles and M. charantia fruit extract.

PubMed

Rashid, Md Mamun Or; Ferdous, Jannatul; Banik, Sujan; Islam, Md Rabiul; Uddin, A H M Mazbah; Robel, Fataha Nur

2016-07-26

Present study has been conducted to know the anthelmintic activity of polyaniline coated silver nanoparticles (AgNPs) synthesized from Momordica charantia fruit extract. By reduction of AgNO3 in presence of NaBH4, silver nanoparticles were prepared. After mixing silver nanoparticles and extracts, coating was given on nanoparticles using polyaniline. Prepared nanoparticles were characterized by Visual, UV, FTIR spectroscopy, SEM techniques, and TEM analysis. The FTIR results implied that AgNPs were successfully synthesized and capped with bio-compounds present in the extract. The result showed that death times of worm were 35.12 ± 0.5 and 59.3 ± 0.3 minutes for M. charantia extract and Ag-nanoparticles individually. But when these two combined together, paralysis and death time fall drastically which were only 6.16 ± 0.6 and 9.1 ± 0.4 minutes respectively. Albendazole tablet was used as standard, which made worms death in 3.66 ± 0.1 minutes. Ag-Extract NPs showed strong anthelmintic activity against worm. This study has paved the way for further research to design new anthelmintic drug from the combination of M. charantia and AgNPs.

High dielectric hyperbranched polyaniline materials.

PubMed

Yan, X Z; Goodson, T

2006-08-03

New organic materials for the purpose of high speed capacitor applications are discussed. The effect of the microcrystalline size dependence of different polyaniline polymeric systems on the dielectric constant is investigated. Two different methods are described for the preparation of the polyaniline dielectric materials. By sonication polymerization, the prepared polyaniline with a suggested hyperbranched structure showed much larger microcrystalline domains in comparison to the conventional linear polyaniline. Investigations of the dielectric constant and capacitance at a relatively high frequency (>100 kHz) suggested that the system with the larger microcrystalline domains (hyperbranched) gives rise to a larger dielectric constant. The mechanism of the increased dielectric response at higher frequencies is investigated by EPR spectroscopy, and these results suggest that delocalized polarons may provide a way to enhance the dielectric response at high frequency.

Preparation and characterization of polyaniline-copper composites by electrical explosion of wire.

PubMed

Liu, Aijie; Bac, Luong Huu; Kim, Jin-Chun; Liu, Lizhu

2012-07-01

Polyaniline-copper composites with a polyacrylic acid (PAA) were synthesized by electrical explosion of wire. Polyaniline (PANI) and PAA were put into the explosion medium, deionized water (DIW) and ethanol, stirred for 24 hrs and sonicated for 2 hrs. These solutions were used as base liquids for explosion process to fabricate Cu nanoparticle. Optical absorption in the UV-visible region of PANI and PANI/PAA-Cu composites was measured in a range of 200-900 nm. X-ray diffraction was used to analyze the phase of the composites. XRD pattern showed the PANI was amorphous and copper was polycrystalline. Two phases of Cu and Cu2O were formed in aqueous solution while single Cu phase was obtained in ethanol solution. Field emission scanning electron microscope was used to observe the microstructure of the composites. The synthesized composites were extensively characterized by Fourier Transform Infrared (FTIR) spectroscopy and electrical measurements.

Structure of Hydrophobically Modified Phytoglycogen Nanoparticles

NASA Astrophysics Data System (ADS)

Atkinson, John; Nickels, Jonathan; Dutcher, John; Katsaras, John

Phytoglycogen is a highly branched, polysaccharide nanoparticle produced by some varieties of plants including sweet corn. These particles are attractive candidates for cosmetic, industrial and biomedical applications. Many of these applications result from phytoglycogen's unique interaction with water: (1) high solubility; (2) low viscosity and high stability in aqueous dispersions; and (3) a remarkable capacity to sequester and retain water. Neutron scattering measurements of native phytoglycogen revealed that the particles have uniform size, uniform radial particle density, and a high level of hydration. Hydrophobically modifying the outer surface of the hydrophilic nanoparticles opens up new applications in food and biomedicine, such as solubilizing and stabilizing bioactive compounds. One such modification is octenyl succinate anhydride (OSA), where the hydrophobicity can be tuned by adjusting the degree of substitution. I will present the results of small angle neutron scattering (SANS) measurements of aqueous dispersions of OSA-modified phytoglycogen with two different degrees of modification. Contrast series SANS measurements have yielded information about the radial density profile, providing insight into the nature of the chemical modification of the particles.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

NASA Astrophysics Data System (ADS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

An improved amperometric L-lactate biosensor based on covalent immobilization of microbial lactate oxidase onto carboxylated multiwalled carbon nanotubes/copper nanoparticles/polyaniline modified pencil graphite electrode.

PubMed

Dagar, Kusum; Pundir, C S

2017-01-01

An improved amperometric l-lactate biosensor was constructed based on covalent immobilization of lactate oxidase (LOx) from Pediococcus species onto carboxylated multiwalled carbon nanotubes (cMWCNT)/copper nanoparticles (CuNPs)/polyaniline (PANI) hybrid film electrodeposited on the surface of a pencil graphite electrode (PGE). The enzyme electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS), while CuNPs synthesized by chemical reduction method, were characterized by transmission electron microscopy (TEM), UV spectrascopy and X-ray diffraction (XRD). The biosensor showed maximum response within 5s at pH 8.0 in 0.05M sodium phosphate buffer and 37°C, when operated at 20mVs -1 . The biosensor had a detection limit of 0.25μM with a wide working range between 1μM-2500μM. The biosensor was employed for measurement of l-lactic acid level in plasma of apparently healthy and diseased persons. Analytical recovery of added lactic acid in plasma was 95.5%. Within- and between-batch coefficients of variations were 6.24% and 4.19% respectively. There was a good correlation (R 2 =0.97) between plasma lactate values as measured by standard enzymatic spectrophotometric method and the present biosensor. The working enzyme electrode was used 180 times over a period of 140 days, when stored at 4°C. Copyright © 2016. Published by Elsevier Inc.

AC conductivity, magnetic and shielding effectiveness studies on polyaniline embedded Co0.5Mn0.5Fe2O4 nanoparticles for electromagnetic interference suppression

NASA Astrophysics Data System (ADS)

Gurusiddesh, M.; Madhu, B. J.; Shankaramurthy, G. J.

2018-05-01

Electrically conducting Polyaniline (PANI)/Co0.5Mn0.5Fe2O4 nanocomposites are synthesized by in situ polymerization of aniline monomer in the presence of Co0.5Mn0.5Fe2O4 nanoparticles. Structural studies on the synthesized samples have been carried out using X-ray diffraction technique, Field emission scanning electron microscopy and Energy dispersive X-ray spectroscopy. Frequency dependent ac conductivity studies on the prepared samples revealed that conductivity of the composite is high compared to Co0.5Mn0.5Fe2O4 nanoparticles. Further, both the samples exhibited hysteresis behavior under the applied magnetic field. Electromagnetic interference (EMI) shielding effectiveness of both the samples decreases with increase in the applied frequency in the studied frequency range. Maximum shielding effectiveness (SE) of 31.49 dB and 62.84 dB were obtained for Co0.5Mn0.5Fe2O4 nanoparticles and PANI/Co0.5Mn0.5Fe2O4 nanocomposites respectively in the studied frequency range. Observed higher EMI shielding in the composites was attributed to its high electrical conductivity.

Fluorescence imaging of the nanoparticles modified with indocyanine green

NASA Astrophysics Data System (ADS)

Gareev, K. G.; Babikova, K. Y.; Postnov, V. N.; Naumisheva, E. B.; Korolev, D. V.

2017-11-01

The comparative research of silica, the magnetite and magnetite-silica nanoparticles modified with fluorescent dyes using gas-phase and liquid-phase methods was conducted. At the content of fluorescent dye comparable in size a particular spectrophotometric method, nanoparticles with fluorescein have up to 1000 times larger overall luminous efficiency. It is revealed that magnetic nanoparticles are characterized by a smaller light efficiency in comparison with silica particles, at the same time particles of a magnetite are most effective at modification with fluorescein, and magnetite-silica particles - at modification with indocyanine green.

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

PubMed Central

Park, Choon-Sang; Kim, Dong Ha; Shin, Bhum Jae; Tae, Heung-Sik

2016-01-01

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique. PMID:28787838

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique.

PubMed

Park, Choon-Sang; Kim, Dong Ha; Shin, Bhum Jae; Tae, Heung-Sik

2016-01-11

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight ( M w ), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

One-step synthesis and characterization of polyaniline nanofiber/silver nanoparticle composite networks as antibacterial agents.

PubMed

Poyraz, Selcuk; Cerkez, Idris; Huang, Tung Shi; Liu, Zhen; Kang, Litao; Luo, Jujie; Zhang, Xinyu

2014-11-26

Through a facile and effective seeding polymerization reaction via a one-step redox/complexation process, which took place in aqueous medium at ambient temperature, silver nanoparticles (Ag NPs) embedded polyaniline nanofiber (PANI NF) networks were synthesized as antibacterial agents. During the reaction, not only NF morphology formation of the resulting conducting polymers (CPs) but also amplification of the aqueous silver nitrate (AgNO3) solutions' oxidative potentials were managed by vanadium pentoxide (V2O5) sol-gel nanofibers, which acted as well-known nanofibrous seeding agents and the auxiliary oxidative agent at the same time. The PANI/Ag nanocomposites were proven to exhibit excellent antibacterial property against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Antibacterial property performance and average life span of the nanocomposite network were optimized through the homogeneous distribution/embedment of Ag NPs within one-dimensional (1-D) PANI NF matrix. The antibacterial efficacy tests and nanocomposite material characterization results further indicated that the sole components of PANI/Ag have a synergistic effect to each other in terms of antibacterial property. Thus, this well-known catalytic seeding approach via a one-step oxidative polymerization reaction can be considered as a general methodology and a substantial fabrication tool to synthesize Ag NP decorated nanofibrillar PANI networks as advanced antibacterial agents.

Fabrication of a novel aptasensor based on three-dimensional reduced graphene oxide/polyaniline/gold nanoparticle composite as a novel platform for high sensitive and specific cocaine detection.

PubMed

Hashemi, Pegah; Bagheri, Hasan; Afkhami, Abbas; Ardakani, Yalda Hosseinzadeh; Madrakian, Tayyebeh

2017-12-15

In the present research, we have developed a novel label free aptasensor based on screen printed carbon electrode (SPCE) modified with three-dimensional magnetic reduced graphene oxide(3D-MRGO)/polyaniline(PA)/gold nanoparticle(AuNP) nanocomposite for impedimetric determination of cocaine. To achieve this goal, a specific thiolated cocaine aptamer was immobilized onto the surface of synthesized nanocomposite. The signaling mechanism of the proposed aptasensor was based on increase in the [Fe(CN) 6 ] 3-/4- charge transfer resistance (R CT ) as an electrochemical probe in the presence of target analyte. In order to collect of 3D-MRGO/PA/AuNP/aptamer on the surface of working electrode easily, a new electrochemical cell was fabricated. The advantages of the new electrochemical cell configuration can be counted as reusing SPCE for several times, obtaining repeatable responses, reducing required volume of electrolyte and probe solution and making proposed method more user-friendly. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of synthesized nanocomposite and modified electrode surface. Under optimized condition, cocaine was determined in a linear concentration range from 0.09 to 85 nM with a detection limit of 0.029 nM by EIS. Also, in order to test applicability of the proposed aptasensor, it was applied to determine cocaine in urine and serum samples and satisfactory results were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

Conducting Polyaniline Nanowire and Its Applications in Chemiresistive Sensing

PubMed Central

Song, Edward; Choi, Jin-Woo

2013-01-01

One dimensional polyaniline nanowire is an electrically conducting polymer that can be used as an active layer for sensors whose conductivity change can be used to detect chemical or biological species. In this review, the basic properties of polyaniline nanowires including chemical structures, redox chemistry, and method of synthesis are discussed. A comprehensive literature survey on chemiresistive/conductometric sensors based on polyaniline nanowires is presented and recent developments in polyaniline nanowire-based sensors are summarized. Finally, the current limitations and the future prospect of polyaniline nanowires are discussed. PMID:28348347

Electrochemical comparison of nickel and nickel hydroxide nanoparticles composited with reduced graphene oxide and polyaniline for their supercapacitor application

NASA Astrophysics Data System (ADS)

Viswanthan, Aranganathan; Shetty, Adka Nityananda

2018-04-01

The reduced graphene oxide/polyaniline/Ni(OH)2 (GP-Ni(OH)2) and reduced graphene oxide/polyaniline/Ni (GP-Ni) nanocomposites were synthesized by facile in situ single step chemical method. The constituents were confirmed by powder-XRD, and the electrochemical characterizations were carried out using cyclic voltammetry(CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The electrochemical contribution of Ni(OH)2 and Ni to their supercapacitance along with reduced graphene oxide and polyaniline was compared. The GP-Ni nanocomposite exhibited a specific capacitance of 266.66 F g-1, energy density of 53.33 W h kg-1 and power density of 1385 W kg-1 at a current density of 0.25 A g-1 and the results were enhanced to 21% and more promising than that of nanocomposite GP-Ni(OH)2.

Gold nanoparticles and polyethylene glycols functionalized conducting polyaniline nanowires for ultrasensitive and low fouling immunosensing of alpha-fetoprotein.

PubMed

Hui, Ni; Sun, Xiaotian; Song, Zhiling; Niu, Shuyan; Luo, Xiliang

2016-12-15

An ultrasensitive biosensor for alpha-fetoprotein was developed based on electrochemically synthesized polyaniline (PANI) nanowires, which were functionalized with gold nanoparticles (AuNPs) and polyethylene glycols (PEG). The prepared PEG/AuNPs/PANI composite, combining the electrical conductivity of the AuNPs/PANI with the robust antifouling ability of PEG, offered an ideal substrate for the development of low fouling electrochemical biosensors. Alpha-fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker, was used as a model analyte, and its antibody was immobilized on the PEG/AuNPs/PANI for the construction of the AFP immunosensor. Using the redox current of PANI as the sensing signal, in addition to the good biocompatibility of PEG/AuNPs and the anti-biofouling property of PEG, the developed immunosensor showed improved biosensing performances, such as wide linear range and ultralow detection limit (0.007pgmL(-1)). More importantly, it is label-free, reagentless and low fouling, making it capable of assaying AFP in real serum samples without suffering from significant interference or biofouling. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensitizing of pyrene fluorescence by β-cyclodextrin-modified TiO2 nanoparticles.

PubMed

Shown, Indrajit; Ujihara, Masaki; Imae, Toyoko

2010-12-15

TiO(2) nanoparticles were synthesized by hydrolysis of tetraisopropyl orthotitanate in an aqueous solution of cyclodextrin. The β-cyclodextrin-modified spherical TiO(2) nanoparticles were water-dispersible and had an average particle diameter of 4.4 ± 1 nm. Pyrene fluorescence was enhanced by increasing the concentration of β-cyclodextrin-modified TiO(2) nanoparticle and the sensitization effect was triply stronger than the case of the β-cyclodextrin only. The increase in a concentration of host (β-cyclodextrin) changes its microenvironment for guest (pyrene), that is, the interaction of pyrene with apolar cavity of β-cyclodextrin increases, resulting in enhancement of fluorescence. The sensitization behavior of pyrene fluorescence in the presence of TiO(2) nanoparticles occurs from the increase in the extinction coefficient of pyrene, demonstrating the charge transfer between pyrene and metal oxide nanoparticle. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

Modification of conductive polyaniline with carbon nanomaterials

NASA Astrophysics Data System (ADS)

Sedaghat, Sajjad; Alavijeh, Mahdi Soleimani

2014-08-01

The synthesis of polyaniline/single-wall nanotube, polyaniline/multi-wall nanotube and polyaniline/single-wall nanotube/graphen nanosheets nanocomposites by in situ polymerization are reported in this study. The substrates were treated with a mixture of concentrated sulfuric acid and concentrated nitric acid before usage to functionalize with carboxylic and hydroxyl groups. Aniline monomers are adsorbed and polymerized on the surface of these fillers. Structural analysis using scanning electron microscopy showed that nanomaterials dispersed into polymer matrix and made tubular structures with diameters several tens to hundreds nanometers depending on the polyaniline content. These nanocomposites can be used for production of excellent electrode materials applications in high-performance supercapacitors.

An all-solid-state lithium/polyaniline rechargeable cell

NASA Astrophysics Data System (ADS)

Li, Changzhi; Peng, Xinsheng; Zhang, Borong; Wang, Baochen

1992-07-01

The performance of an all-solid-state cell having a lithium negative electrode, a modified polyethylene oxide (PEO)-epoxy resin (ER) electrolyte, and a polyaniline (PAn) positive electrode has been studied using cyclic voltammetry, charge/discharge cycling, and polarization curves at various temperatures. The redox reaction of the PAn electrode at the PAn/modified PEO-ER interface exhibits good reversibility. At 50-80 C, the Li/PEO-ER-LiClO4/PAn cell shows more than 40 charge/discharge cycles, 90 percent charge/discharge efficiency, and 54 W h kg discharge energy density (on PAn weight basis) at 50 micro-A between 2 and 4 V. The polarization performance of the battery improves steadily with increase in temperature.

Insight into capacitive performance of polyaniline/graphene oxide composites with ecofriendly binder

NASA Astrophysics Data System (ADS)

Bilal, Salma; Fahim, Muhammad; Firdous, Irum; Ali Shah, Anwar-ul-Haq

2018-03-01

The behaviour of gold electrode modified with polyaniline/graphene oxide composites (PGO) was studied for electrochemical and charge storage properties in aqueous acidic media. The surface of gold electrode was modified with aqueous slurry of PGO by using Carboxymethyl cellulose (CMC) as binder. The intercalation of polyaniline in the GO layers, synthesized by in situ polymerization was confirmed by scanning electron microscopy (SEM). The electrochemical behaviour and charge storing properties were investigated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS). A high specific capacitance of 1721 F g-1 was obtained for PGO with 69.8% retention of capacitance even after 1000 voltammetric cycles in the potential range of 0-0.9 V at 20 mV s-1. EIS indicated low charge transfer resistance (Rct) and solution resistance (Rs) values of 0.51 Ω and 0.07 Ω, respectively. This good performance of PGO coated electrode is attributed to the use of CMC binder which generate a high electrode/ electrolyte contact area and short path lengths for electronic transport and electrolyte ion.

Polyaniline modified flexible conducting paper for cancer detection

NASA Astrophysics Data System (ADS)

Kumar, Saurabh; Sen, Anindita; Kumar, Suveen; Augustine, Shine; Yadav, Birendra K.; Mishra, Sandeep; Malhotra, Bansi D.

2016-05-01

We report results of studies relating to the fabrication of a flexible, disposable, and label free biosensing platform for detection of the cancer biomarker (carcinoembryonic antigen, CEA). Polyaniline (PANI) has been electrochemically deposited over gold sputtered paper (Au@paper) for covalent immobilization of monoclonal carcinoembryonic antibodies (anti-CEA). The bovine serum albumin (BSA) has been used for blocking nonspecific binding sites at the anti-CEA conjugated PANI/Au@Paper. The PANI/Au@Paper, anti-CEA/PANI/Au@Paper, and BSA/anti-CEA/PANI/Au@Paper platforms have been characterized using scanning electron microscopy, X-ray diffraction, Fourier transmission infrared spectroscopy, chronoamperometry, and electrochemical impedance techniques. The results of the electrochemical response studies indicate that this BSA/anti-CEA/PANI/Au@paper electrode has sensitivity of 13.9 μA ng-1 ml cm2, shelf life of 22 days, and can be used to estimate CEA in the range of 2-20 ng ml-1. This paper sensor has been validated by detection of CEA in serum samples of cancer patients via immunoassay technique.

Flexible diode of polyaniline/ITO heterojunction on PET substrate

NASA Astrophysics Data System (ADS)

Bera, A.; Deb, K.; Kathirvel, V.; Bera, T.; Thapa, R.; Saha, B.

2017-10-01

Hybrid organic-inorganic heterojunction between polyaniline and ITO film coated on flexible polyethylene terephthalate (PET) substrate has been prepared through vapor phase polymerization process. Polaron and bipolaron like defect states induced hole transport and exceptional mobility makes polyaniline a noble hole transport layer. Thus a p-n junction has been obtained between the hole transport layer of polyaniline and highly conductive n-type layer of ITO film. The synthesis process was carried out using FeCl3 as polymerizing agent in the oxidative chemical polymerization process. The prepared polyaniline has been found to be crystalline on characterization through X-ray diffraction measurement. X-ray photoelectron spectroscopic measurements were done for compositional analysis of the prepared film. The UV-vis-NIR absorbance spectra obtained for polyaniline shows the characteristics absorbance as observed for highly conductive polyaniline and confirms the occurrence of partially oxidized emeraldine form of polyaniline. The energy band gap of the polyaniline has been obtained as 2.52 eV, by analyzing the optical transmittance spectra. A rectifying behavior has been observed in the electrical J-V plot, which is of great significance in designing polymer based flexible electronic devices.

Thermochromic effect in synthetic opal/polyaniline composite structures

NASA Astrophysics Data System (ADS)

Rahman, F.; Khokhar, A. Z.

2009-02-01

The design and construction of a novel storage/indicator bilayer system is described where ammonia gas stored in a porous material can be used to dope a colour-changing polyaniline film. Both reversible and irreversible colour change effects are possible. A thin synthetic opal film is coupled to a polyaniline film in a parallel plate glass cell with ammonia gas adsorbed on the silica balls that form the opal structure. When heated and cooled, ammonia reversibly exchanges between the opal and polyaniline films causing a very distinct change in the colour of the polyaniline film. This thermochromic effect is also electrically detectable because of the large concomitant change in the resistivity of the polyaniline film that accompanies its colour change.

Sustained release and permeation of timolol from surface-modified solid lipid nanoparticles through bioengineered human cornea.

PubMed

Attama, A A; Reichl, S; Müller-Goymann, C C

2009-08-01

The aim of the study was to formulate and evaluate surface-modified solid lipid nanoparticles sustained delivery system of timolol hydrogen maleate, a prototype ocular drug using a human cornea construct. Surface-modified solid lipid nanoparticles containing timolol with and without phospholipid were formulated by melt emulsification with high-pressure homogenization and characterized by particle size, wide-angle X-ray diffraction, encapsulation efficiency, and in vitro drug release. Drug transport studies through cornea bioengineered from human donor cornea cells were carried out using a modified Franz diffusion cell and drug concentration analyzed by high-performance liquid chromatography. Results show that surface-modified solid lipid nanoparticles possessed very small particles (42.9 +/- 0.3 nm, 47.2 +/- 0.3 nm, 42.7 +/- 0.7 nm, and 37.7 +/- 0.3 nm, respectively for SM-SLN 1, SM-SLN 2, SM-SLN 3, and SM-SLN 4) with low polydispersity indices, increased encapsulation efficiency (> 44%), and sustained in vitro release compared with unmodified lipid nanoparticles whose particles were greater than 160 nm. Permeation of timolol hydrogen maleate from the surface-modified lipid nanoparticles across the cornea construct was sustained compared with timolol hydrogen maleate solution in distilled water. Surface-modified solid lipid nanoparticles could provide an efficient way of improving ocular bioavailability of timolol hydrogen maleate.

Perspectives on State-of-the-Art Carbon Nanotube/Polyaniline and Graphene/Polyaniline Composites for Hybrid Supercapacitor Electrodes.

PubMed

Srikanth, Vadali V S S; Ramana, Gedela Venkata; Kumar, Puttapati Sampath

2016-03-01

Supercapacitors are attractive alternative energy storage sources. They offer high energy/power density with other characteristics like fast discharge/charge time, long operation stability, safety etc. In a supercapacitor, working electrode material is the principal constituent. At present there are numerous electrode materials (with properties) suitable for their use in hybrid type supercapacitors. Carbon/polyaniline (PANi) composites are one class of such electrode materials. Here, perspectives on state-of-the-art carbon/PANi composites namely carbon nanotube/polyaniline and graphene/polyaniline composites expedient as hybrid type supercapacitor electrode materials will be presented.

Patterned polyaniline encapsulated in titania nanotubes for electrochromism.

PubMed

Lv, Haiming; Wang, Yi; Pan, Lei; Zhang, Leipeng; Zhang, Hangchuan; Shang, Lei; Qu, Huiying; Li, Na; Zhao, Jiupeng; Li, Yao

2018-02-21

In this article, we report the preparation of a TiO 2 nanotube array (TNA) film used as a transparent electrochromic material and a TNA/polyaniline patterned hybrid electrochromic film utilized as an information display material. The TNA film was fabricated by an anodizing process, and a surface patterned TNA with extreme wettability contrast (hydrophilic/hydrophobic) on a TNA surface through self-assembly (SAM) and photocatalytic lithography is fabricated. Then the TNA/polyaniline hybrid film was prepared by electrodeposition of aniline in an aqueous solution. Finally, the electrochromic properties of the TNA film and the TNA/polyaniline hybrid film were investigated. Compared with neat TNA film and polyaniline (PANI) films, the hybrid film shows a much higher optical contrast in the near infrared range. The TNA/polyaniline hybrid film shows higher coloration efficiencies of 24.4 cm 2 C -1 at a wavelength of 700 nm and 17.1 cm 2 C -1 at a wavelength of 1050 nm compared to the TNA coloration efficiency. The color switching time (20.9 s or 22.9 s) of TNA/polyaniline is faster than TNA.

Surface modified PLGA nanoparticles for brain targeting of Bacoside-A.

PubMed

Jose, S; Sowmya, S; Cinu, T A; Aleykutty, N A; Thomas, S; Souto, E B

2014-10-15

The present paper focuses on the development and in vitro/in vivo characterization of nanoparticles composed of poly-(D,L)-Lactide-co-Glycolide (PLGA) loading Bacoside-A, as a new approach for the brain delivery of the neuroprotective drug for the treatment of neurodegenerative disorders (e.g. Alzheimer Disease). Bacoside-A-loaded PLGA nanoparticles were prepared via o/w emulsion solvent evaporation technique. Surface of the nanoparticles were modified by coating with polysorbate 80 to facilitate the crossing of the blood brain barrier (BBB), and the processing parameters (i.e. sonication time, the concentration of polymer (PLGA) and surfactant (polysorbate 80), and drug-polymer ratio) were optimized with the aim to achieve a high production yield. Brain targeting potential of the nanoparticles was evaluated by in vivo studies using Wistar albino rats. The nanoparticles produced by optimal formulation were within the nanosized range (70-200 nm) with relatively low polydispersity index (0.391 ± 1.2). The encapsulation efficiency of Bacoside-A in PLGA nanoparticles was 57.11 ± 7.11%, with a drug loading capacity of 20.5 ± 1.98%. SEM images showed the spherical shape of the PLGA nanoparticles, whereas their low crystallinity was demonstrated by X-ray studies, which also confirmed no chemical interactions between the drug and polymer molecules. The in vitro release of Bacoside-A from the PLGA nanoparticles followed a sustained release pattern with a maximum release of up to 83.04 ± 2.55% in 48 h. When compared to pure drug solution (2.56 ± 1.23 μg/g tissue), in vivo study demonstrated higher brain concentration of Bacoside-A (23.94 ± 1.74 μg/g tissue) suggesting a significant role of surface coated nanoparticles on brain targeting. The results indicate the potential of surface modified PLGA nanoparticles for the delivery of Bacoside-A to the brain. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and characterization of polyaniline-cadmium sulfide nanocomposite for gas sensor application

NASA Astrophysics Data System (ADS)

Al-Jawad, Selma M. H.; Rafic, Sewench N.; Muhsen, Mustafa M.

2017-09-01

Polyaniline (PANI) was prepared by chemical oxidative polymerization of aniline monomers as emeraldine salt form. By the same method, polyaniline-cadmium sulfide nanocomposites were synthesized in the presence of different percentages (10-50 wt.%) of cadmium sulfide (CdS) which was prepared by using sol-gel method. The optical band gap was decrease with increasing of CdS concentration, that is obtained from UV-VIS measurements. From SEM and AFM, there is uniform distribution for cadmium sulfide nanoparticles in the PANI matrix. The electrical measurements of nanocomposites exhibit the effect of crystallite size and the high resistivity of CdS on the resistivity of nanocomposites. Emeraldine salt PANI, CdS and PANI-CdS nanocomposites were investigated as gas sensors. From this investigation, the sensitivity of PANI-CdS for NO2 gas increase with the increasing of operation temperature and the optimum sensitivity was obtained at 200∘C. The sensitivity of nanocomposites at best temperature (200∘C) was increased and faster response time with the increasing of CdS contents.

Surface-modified silk hydrogel containing hydroxyapatite nanoparticle with hyaluronic acid-dopamine conjugate.

PubMed

Kim, Hyung Hwan; Park, Jong Bo; Kang, Min Ji; Park, Young Hwan

2014-09-01

Silk fibroin/hydroxyapatite (SF/HAp) composite hydrogels were fabricated in this study, having different HAp contents (0-33 wt%) in SF matrix hydrogel. Surface modification of HAp nanoparticle with hyaluronic acid (HA)-dopamine (DA) conjugate improved a dispersibility of HAp in aqueous SF solution due to its negatively charged surface and therefore, fabrication of the SF composite hydrogel having HAp nanoparticles inside could be possible. Zeta potential of surface-modified HAP was examined by ELS. It demonstrates that surface of HAp was well modified to a negative charge with HA-DA. Morphological structure of SF hydrogel containing surface-modified HAp was examined by FE-SEM for analyzing pore structure of hydrogel and deposition of HAp nanoparticle in SF hydrogel. It was found that HAp nanoparticles were uniformly deposited on the pore wall of SF hydrogel. Structural characteristics of SF/HAp composite hydrogel was performed using X-ray diffraction and FT-IR analysis. It was found that β-sheet crystal conformation of SF was significantly influenced by the HAp content during gelation of a mixture of SF and HAp. As a result of MTT assay, the SF/HAp composite hydrogel showed excellent cell proliferation ability. Therefore, it is expected that SF hydrogel containing HAp nanoparticles has a high potential as bone regeneration scaffold. Copyright © 2014 Elsevier B.V. All rights reserved.

Spontaneous synthesis of gold nanoparticles on gum arabic-modified iron oxide nanoparticles as a magnetically recoverable nanocatalyst.

PubMed

Wu, Chien-Chen; Chen, Dong-Hwang

2012-06-19

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles.

Spontaneous synthesis of gold nanoparticles on gum arabic-modified iron oxide nanoparticles as a magnetically recoverable nanocatalyst

PubMed Central

2012-01-01

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles. PMID:22713480

Nano-particle modified stationary phases for high-performance liquid chromatography.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Connolly, Damian; He, Xiaoyun; Floris, Patrick; Duffy, Emer; Paull, Brett

2013-08-07

This review covers the latest developments and applications of nano-materials in stationary phase development for various modes of high-performance liquid chromatography. Specific attention is placed upon the development of new composite phases, including the synthetic and immobilisation strategies used, to produce either encapsulated nano-particles, or surface attached nano-particles, layers, coatings and other structures. The resultant chromatographic applications, where applicable, are discussed with comment upon enhanced selectivity and/or efficiency of the nano-particle modified phases, where such effects have been identified. In the main this review covers developments over the past five years and is structured according to the nature of the nano-particles themselves, including carbonaceous, metallic, inorganic, and organopolymer based materials.

Polyaniline modified flexible conducting paper for cancer detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Saurabh; Sen, Anindita; Kumar, Suveen

We report results of studies relating to the fabrication of a flexible, disposable, and label free biosensing platform for detection of the cancer biomarker (carcinoembryonic antigen, CEA). Polyaniline (PANI) has been electrochemically deposited over gold sputtered paper (Au@paper) for covalent immobilization of monoclonal carcinoembryonic antibodies (anti-CEA). The bovine serum albumin (BSA) has been used for blocking nonspecific binding sites at the anti-CEA conjugated PANI/Au@Paper. The PANI/Au@Paper, anti-CEA/PANI/Au@Paper, and BSA/anti-CEA/PANI/Au@Paper platforms have been characterized using scanning electron microscopy, X-ray diffraction, Fourier transmission infrared spectroscopy, chronoamperometry, and electrochemical impedance techniques. The results of the electrochemical response studies indicate that this BSA/anti-CEA/PANI/Au@paper electrodemore » has sensitivity of 13.9 μA ng{sup −1} ml cm{sup 2}, shelf life of 22 days, and can be used to estimate CEA in the range of 2–20 ng ml{sup −1}. This paper sensor has been validated by detection of CEA in serum samples of cancer patients via immunoassay technique.« less

Investigations on silver/polyaniline electrodes for electrochemical supercapacitors.

PubMed

Patil, Dipali S; Shaikh, J S; Pawar, S A; Devan, R S; Ma, Y R; Moholkar, A V; Kim, J H; Kalubarme, R S; Park, C J; Patil, P S

2012-09-14

Polyaniline (PANI) and silver doped polyaniline (Ag/PANI) thin films were deposited on stainless steel substrates by a dip coating technique. To study the effect of doping concentration of Ag on the specific capacitance of PANI the concentration of Ag was varied from 0.3 to 1.2 weight percent. Fourier transform-infrared and Fourier transform-Raman spectroscopy, and energy dispersion X-ray techniques were used for the phase identification and determination of the doping content in the PANI films, respectively. The surface morphology of the films was examined by Field Emission Scanning Electron Microscopy, which revealed a nanofiber like structure for PANI and nanofibers with bright spots of Ag particles for the Ag/PANI films. There was decrease in the room temperature electrical resistivity of the Ag/PANI films of the order of 10(2) with increasing Ag concentration. The supercapacitive behavior of the electrodes was tested in a three electrode system using 1.0 M H(2)SO(4) electrolyte. The specific capacitance increased from 285 F g(-1) (for PANI) to 512 F g(-1) for Ag/PANI at 0.9 weight percent doping of Ag, owing to the synergic effect of PANI and silver nanoparticles. This work demonstrates a simple strategy of improving the specific capacitance of polymer electrodes and may also be easily adopted for other dopants.

Surface-modified nanoparticles as anti-biofilm filler for dental polymers

PubMed Central

Zaltsman, Nathan; Ionescu, Andrei C.; Weiss, Ervin I.; Brambilla, Eugenio; Beyth, Shaul

2017-01-01

The objective of the study was to synthesis silica nanoparticles modified with (i) a tertiary amine bearing two t-cinnamaldehyde substituents or (ii) dimethyl-octyl ammonium, alongside the well-studied quaternary ammonium polyethyleneimine nanoparticles. These were to be evaluated for their chemical and mechanical properties, as well for antibacterial and antibiofilm activity. Samples were incorporated in commercial dental resin material and the degree of monomer conversion, mechanical strength, and water contact angle were tested to characterize the effect of the nanoparticles on resin material. Antibacterial activity was evaluated with the direct contact test and the biofilm inhibition test against Streptococcus mutans. Addition of cinnamaldehyde-modified particles preserved the degree of conversion and compressive strength of the base material and increased surface hydrophobicity. Quaternary ammonium functional groups led to a decrease in the degree of conversion and to low compressive strength, without altering the hydrophilic nature of the base material. In the direct contact test and the anti-biofilm test, the polyethyleneimine particles exhibited the strongest antibacterial effect. The cinnamaldehyde-modified particles displayed antibiofilm activity, silica particles with quaternary ammonium were ineffective. Immobilization of t-cinnamaldehyde onto a solid surface via amine linkers provided a better alternative to the well-known quaternary ammonium bactericides. PMID:29244848

Stable, concentrated solutions of polyaniline using amines as gel inhibitors

DOEpatents

Wang, Hsing-Lin; Mattes, Benjamin R.

2002-01-01

Stable, concentrated solutions of high-molecular weight polyaniline using amines as gel inhibitors. Certain amine compounds (gel inhibitors) are used to form highly concentrated, stable solutions of the emeraldine base form of polyaniline in numerous organic solvents from which coatings, films and fibers are readily prepared without problems associated with rapid gelation which occurs when concentrated solutions are attempted without the use of the gel inhibitors of the present invention. Tertiary amines are used to solubilize low-molecular weight fractions (M.sub.w <120,000, M.sub.n <30,000) of the pernigraniline, emeraldine, and leucoemeraldine oxidation states of polyaniline as concentrated (>20 wt. %) polyaniline solutions, while primary and secondary amines are used to produce solutions having 15-40 wt % of high-molecular weight polyaniline [M.sub.w.gtoreq.120,000, M.sub.n.gtoreq.30,000]. Concentrated solutions of polyaniline co-polymers or ring and/or nitrogen-substituted polyanilines may also be prepared.

A Silver Nanoparticle-Modified Evanescent Field Optical Fiber Sensor for Methylene Blue Detection

PubMed Central

Luo, Ji; Yao, Jun; Lu, Yonggang; Ma, Wenying; Zhuang, Xuye

2013-01-01

A silver nanoparticle-modified evanescent field optical fiber sensor based on a MEMS microchannel chip has been successfully fabricated. Experimental results show that the sensor response decreases linearly with increasing concentration of analyte. Over a range of methylene blue concentrations from 0 to 0.4 μmol/mL, the sensor response is linear (R = 0.9496). A concentration variation of 0.1 μmol/mL can cause an absorbance change of 0.402 dB. Moreover, the optical responses of the same sensing fiber without decoration and modified with silver nanoparticles have also been compared. It can be observed that the output intensity of the Ag nanoparticle-modified sensor is enhanced and the sensitivity is higher. Meanwhile, the absorbance spectra are found to be more sensitive to concentration changes compared to the spectra of the peak wavelength. PMID:23519353

The Polyanilines: A Novel Class of Conducting Polymers

DTIC Science & Technology

1992-06-19

yield pos~ive and negative solitons. Other conducting polymers are briefly discussed. The polyanilines , a large class of versatile conducting polymers...Speia TEC-9NTlCAL REPORT NO.: 1992-35 - "THE POLYANILINES : A NOVEL CLASS OF CONDUCTING POLYMERS" by A.G. MacDiarmid Accepted for Publication in...34The Polyanilines : A Novel Class of Conducting Polymers," Proceed. Nobel Symposium 81, in Cpniuaated Polymers and Related Materials: The Interconnection

Fabrication and evaluation of evanescent wave absorption based polyaniline-cladding modified fiber optic urea biosensor

NASA Astrophysics Data System (ADS)

Botewad, S. N.; Pahurkar, V. G.; Muley, G. G.

2018-01-01

The fabrication and study of cladding modified intrinsic fiber optic urea biosensor has been reported in the present investigation. A simple cladding modification technique was used to construct the sensor by uncladding the small portion from optical fiber. Further bare core was decorated by supportive porous, chemically and optically sensitive matrix material polyaniline (PANI) as an active cladding for enzyme residency. Enzyme-urease (Urs) was cross-linked on the active cladding region via glutaraldehyde solution. Confirmation of the prepared PANI in proper form determined by ultraviolet-visible and Fourier transform infrared spectroscopic techniques. X-ray diffraction technique was employed for nature and compatibility examination of PANI. Sensor parameters such as sensitivity, selectivity, stability and lower detection limit have been analyzed by absorption variation study in evanescent wave field. The response of prepared sensor was studied towards urea in the wide concentration range 100 nM-100 mM and confirmed its lowest detection limit as 100 nM. The stability of sensor was found 28 days with little variation in response. The fabricated sensor has not shown any response towards interference species like glucose, ascorbic acid, L-alanine, L-arginine and their combination with urea solution and hence found selective for urea solution only.

Enhancement of Thermal Damage to Adenocarcinoma Cells by Iron Nanoparticles Modified with MUC1 Aptamer.

PubMed

Guo, Fangqin; Hu, Yan; Yu, Lianyuan; Deng, Xiaoyuan; Meng, Jie; Wang, Chen; Yang, Xian-Da

2016-03-01

Hyperthermia cancer treatment is an adjunctive therapy that aims at killing the tumor cells with excessive heat that is usually generated by metal contrasts exposed to alternating magnetic field. The efficacy of hyperthermia is often limited by the heat damage to normal tissue due to indiscriminate distribution of the metal contrasts within the body. Tumor-targeting metal contrasts may reduce the toxicity of hyperthermia and improve the efficacy of thermotherapy against cancer. MUC1 is a glycoprotein over expressed in most adenocarcinomas, and represents an attractive therapeutic target. In this study, a MUC1 aptamer is conjugated with iron nanoparticles to construct adenocarcinoma-targeting metal contrasts. DNA hybridization studies confirmed that the aptamers were conjugated to the iron nanoparticles. Importantly, more aptamer-modified nanoparticles attached to the MUC1-positive cancer cells compared with the unmodified nanoparticles. Moreover, aptamer-modified nanoparticles significantly enhanced the targeted hyperthermia damage to MUC1-positive cancer cells in vitro (p < 0.05). The results suggest that MUC1 aptamer-modified metal particles may have potential in development of targeted hyperthermia therapy against adenocarcinomas.

Electrically Conducting Polyaniline Microtube Blends

DTIC Science & Technology

2004-08-01

SMC-TR-05-01 AEROSPACE REPORT NO. TR-2004(8565)-4 Electrically Conducting Polyaniline Microtube Blends 1 August 2004 Prepared by A. R. HOPKINS, R. A...It is published only for the exchange and stimulation of ideas. Michael Zambrana SMC/AXE Form Approved REPORT DOCUMENTATION PAGE OMB No. 0704-0188...0001 Electrically Conducting Polyaniline Microtube Blends 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER A. R. Hopkins, R

Microspherical polyaniline/graphene nanocomposites for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Cao, Hailiang; Zhou, Xufeng; Zhang, Yiming; Chen, Liang; Liu, Zhaoping

2013-12-01

Polyaniline/graphene nanocomposites with microspherical morphology and porous structure are prepared as electrode materials for supercapacitors. Using few-layer graphene obtained by liquid phase exfoliation of graphite as the raw material, porous graphene microspheres are produced by spray drying, and are then employed as the substrates for the growth of polyaniline nanowire arrays by in situ polymerization. In the composite, interconnected graphene sheets with few structural defects constitute a high-efficient conductive network to improve the electrical conductivity of polyaniline. Furthermore, the microspherical architecture prevents restacking of polyaniline/graphene composite nanosheets, thus facilitates fast diffusion of electrolytes. Consequently, the nanocomposite exhibits excellent electrochemical performance. A specific capacitance of 338 F g-1 is reached in 1 M H2SO4 at a scan rate of 20 mV s-1, and a high capacity retention rate of 87.4% after 10,000 cycles at a current density of 3 A g-1 can be achieved, which suggests that the polyaniline/graphene composite with such kind of 3D architecture is a promising electrode material for high-performance supercapacitors.

Synthesis of highly conductive cotton fiber/nanostructured silver/polyaniline composite membranes for water sterilization application

NASA Astrophysics Data System (ADS)

Abu-Thabit, Nedal Y.; Basheer, Rafil A.

2014-09-01

Electrically conductive composite membranes (ECCMs) composed of cotton fibers, conductive polyaniline and silver nanostructures were prepared and utilized as electrifying filter membranes for water sterilization. Silver metal and polyaniline were formed in situ during the oxidative polymerization of aniline monomers in the presence of silver nitrate as weak oxidizing agent. The reaction was characterized by long induction period and the morphology of the obtained ECCMs contained silver nanoparticles and silver flakes of 500-1000 nm size giving a membrane electrical resistance in the range of 10-30 Ohm sq-1. However, when dimethylformamide (DMF) was employed as an auxiliary reducing agent to trigger and speed up the polymerization reaction, silver nanostructures such as wires, ribbons, plates were formed and were found to be embedded between polyaniline coating and cotton fibers. These ECCMs exhibited a slightly lower resistance in the range of 2-10 Ohm sq.-1 and, therefore, were utilized for the fabrication of a bacteria inactivation device. When water samples containing 107-108 CFU mL-1 E. coli bacteria were passed through the prepared ECCMs by gravity force, with a filtration rate of 0.8 L h-1 and at an electric potential of 20 V, the fabricated device showed 92% bacterial inactivation efficiency. When the treated solution was passed through the membrane for a second time under the same conditions, no E. coli bacteria was detected.

Chitosan nanoparticles as a modified diclofenac drug release system

NASA Astrophysics Data System (ADS)

Duarte Junior, Anivaldo Pereira; Tavares, Eraldo José Madureira; Alves, Taís Vanessa Gabbay; de Moura, Márcia Regina; da Costa, Carlos Emmerson Ferreira; Silva Júnior, José Otávio Carréra; Ribeiro Costa, Roseane Maria

2017-08-01

This study evaluated a modified nanostructured release system employing diclofenac as a drug model. Biodegradable chitosan nanoparticles were prepared with chitosan concentrations between 0.5 and 0.8% ( w/ v) by template polymerization method using methacrylic acid in aqueous solution. Chitosan-poly(methacrylic acid) (CS-PMAA) nanoparticles showed uniform size around 50-100 nm, homogeneous morphology, and spherical shape. Raw material and chitosan nanoparticles were characterized by thermal analysis, Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM), confirming the interaction between chitosan and methacrylic acid during nanoparticles preparation. Diclofenac sorption on the chitosan nanoparticles surface was achieved by incubation in water/ethanol (1:1) drug solution in concentrations of 0.5 and 0.8 mg/mL. The diclofenac amount sorbed per gram of CS-PMAA nanoparticles, when in a 0.5 mg/mL sodium diclofenac solution, was as follows: 12.93, 15, 20.87, and 29.63 mg/g for CS-PMAA nanoparticles 0.5, 0.6, 0.7, and 0.8% ( w/ v), respectively. When a 0.8 mg/mL sodium diclofenac solution was used, higher sorption efficiencies were obtained: For CS-PMAA nanoparticles with chitosan concentrations of 0.5, 0.6, 0.7, and 0.8% ( w/ v), the sorption efficiencies were 33.39, 49.58, 55.23, and 67.2 mg/g, respectively. Diclofenac sorption kinetics followed a second-order kinetics. Drug release from nanoparticles occurred in a period of up to 48 h and obeyed Korsmeyer-Peppas model, which was characterized mainly by Fickian diffusion transport. [Figure not available: see fulltext.

Adsorption of environmental pollutants using magnetic hybrid nanoparticles modified with β-cyclodextrin

NASA Astrophysics Data System (ADS)

Wang, Niejun; Zhou, Lilin; Guo, Jun; Ye, Qiquan; Lin, Jin-Ming; Yuan, Jinying

2014-06-01

Graft through strategy was utilized to coat magnetic Fe3O4 nanoparticles with poly(glycidyl methacrylate) using ordinary radical polymerization and then β-cyclodextrin was linked onto the surface of nanoparticles. With these nanoparticles modified with cyclodextrin groups, adsorption of two model environmental pollutants, bisphenol A and copper ions, was studied. Host-guest interactions between cyclodextrin and aromatic molecules had a great contribution to the adsorption of bisphenol A, while multiple hydroxyls of cyclodextrin also helped the adsorption of copper ions. These magnetic nanoparticles could be applied in the elimination, enrichment and detection of some environmental pollutants.

Electrical and optical properties of nickel ferrite/polyaniline nanocomposite.

PubMed

Khairy, M; Gouda, M E

2015-07-01

Polyaniline-NiFe2O4 nanocomposites (PANI-NiFe2O4) with different contents of NiFe2O4 (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol-gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI-NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg  = 1.0 for PANI-NiFe2O4 nanocomposite.

Sustained magnetization oscillations in polyaniline-Fe{sub 3}O{sub 4} nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Araújo, A. C. V. de; Rodrigues, A. R., E-mail: ricalde@df.ufpe.br; Machado, F. L. A.

2015-09-28

We report experiments with polyaniline-Fe{sub 3}O{sub 4} (PANI-Fe{sub 3}O{sub 4}) nanocomposites synthesized under several different conditions. With a reaction carried out at room temperature and assisted by intense ultra-violet (UV) irradiation, we observe sustained oscillations in the magnetization with a period of about 25 min. The oscillations are interpreted as the result of an oscillatory chemical reaction in which part of the Fe{sup +2} ions of magnetite, Fe{sub 3}O{sub 4}, are oxidized by the UV irradiation to form Fe{sup +3} so that a fraction of the magnetite content transforms into maghemite, γ-Fe{sub 2}O{sub 3}. Then, Fe{sup +3} ions at themore » nanoparticle surfaces are reduced and transformed back into Fe{sup +2}, when acting as an oxidizing agent for polyaniline in the polymerization process. Since maghemite has smaller magnetization than magnetite, the oscillating chemical reaction results in the oscillatory magnetization. The observations are interpreted with the Lotka-Volterra nonlinear coupled equations with parameters that can be adjusted to fit very well the experimental data.« less

Polyaniline-encapsulated silicon on three-dimensional carbon nanotubes foam with enhanced electrochemical performance for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhou, Xiaoming; Liu, Yang; Du, Chunyu; Ren, Yang; Mu, Tiansheng; Zuo, Pengjian; Yin, Geping; Ma, Yulin; Cheng, Xinqun; Gao, Yunzhi

2018-03-01

Seeking free volume around nanostructures for silicon-based anodes has been a crucial strategy to improve cycling and rate performance in the next generation Li-ion batteries. Herein, through a simple pyrolysis and in-situ polymerization approach, the low cost commercially available melamine foam as a soft template converts carbon nanotubes into highly dispersed and three-dimensionally interconnected framework with encapsulated silicon/polyaniline hierarchical nanoarchitecture. This unique core-sheath structure based on carbon nanotubes foam integrates a large number of mesoporous, thus providing well-accessible space for electrolyte wetting, whereas the carbon nanotubes matrix serves as conductive thoroughfares for electron transport. Meanwhile, the outer polyaniline coated on silicon nanoparticles provides effective space for volume expansion of silicon, further inhibiting the active material escape from the current collector. As expected, the PANI-Si@CNTs foam exhibits a high initial specific capacity of 1954 mAh g-1 and retains 727 mAh g-1 after 100 cycles at 100 mA g-1, which can be attributed to highly electrical conductivity of carbon nanotubes and protective layer of polyaniline sheath, together with three-dimensionally interconnected porous skeleton. This facile structure can pave a way for large scale synthesis of high durable silicon-based anodes or other electrode materials with huge volume expansion.

Manufacturing conductive polyaniline/graphite nanocomposites with spent battery powder (SBP) for energy storage: A potential approach for sustainable waste management.

PubMed

Duan, Xiaojuan; Deng, Jinxing; Wang, Xue; Guo, Jinshan; Liu, Peng

2016-07-15

A potential approach for sustainable waste management of the spent battery material (SBM) is established for manufacturing conductive polyaniline (PANI) nanocomposites as electrode materials for supercapacitors, following the principle of "What comes from the power should be used for the power". The ternary nanocomposites (G/MnO2/PANI) containing PANI, graphite powder (G) and remanent MnO2 nanoparticles and the binary nanocomposites of polyaniline and graphite powder (G/PANI) are synthesized by the chemical oxidative polymerization of aniline in hydrochloric aqueous solution with the MnO2 nanoparticles in the spent battery powder (SBP) as oxidant. The G/PANI sample, which was prepared with MnO2/aniline mole ratio of 1:1 with 1.0mL aniline in 50mL of 1.0molL(-1) HCl, exhibits the electrical conductivity of 22.22Scm(-1), the highest specific capacitance up to 317Fg(-1) and the highest energy density of 31.0 Wh kg(-1), with retention of as high as 84.6% of its initial capacitance after 1000 cycles, indicating good cyclic stability. Copyright © 2016 Elsevier B.V. All rights reserved.

Structural and electrical study of ZrO{sub 2} nanoparticles modified with surfactants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sidhu, Gaganpreet Kaur; Kumar, Rajesh, E-mail: rajeshbaboria@gmail.com; Tripathi, S. K.

2015-06-24

Zirconia ceramic is one of the most investigated materials for its outstanding mechanical properties and ionic conduction properties, due to its high oxygen ion conduction. In order to achieve novel properties of zirconia nanoparticles, nanoparticles of zirconia are modified by using two different surfactants (SDS and CTAB) were prepared by in-situ method using zirconia/surfactant dispersions. Zirconia nanoparticles with surfactant (SDS or CTAB) were synthesized by hydrothermal method. The structural and optical properties of Zirconia/surfactant nanoparticles were investigated comprehensively by X-Ray diffraction (XRD), and electrical measurements. XRD highlights the crystalline behavior of nanoparticles.

Hydrophobically Modified Glycol Chitosan Nanoparticles for Targeting Breast Cancer Microcalcification Using Alendronate Probes

NASA Astrophysics Data System (ADS)

Vishnu, Kamalakannan

In 2016, invasive breast cancer was diagnosed in about 246,660 women and 2,600 men. An additional 61,000 new cases of in situ breast cancer was diagnosed in women. Microcalcifications are most common abnormalities detected by mammography for breast cancer, present in about 30% of all malignant breast lesions. Tumor specific biomarkers are used for targeting these abnormalities. Nanoparticles with multimodal and combinatorial therapies and conjunction of bio-ligands for specific molecular targeting using surface modifications effectually deliver a variety of drugs and are simultaneously used to image tumor progression. Alendronate, a germinal bisphosphonate conjugation as a targeting ligand would improve the nanoparticle's direct binding to hydroxyapatite (HA) mimicking calcified spots in breast cancer lesions. In this study, the hydrophobically modified glycol chitosan (HGC) micelle was modified with alendronate surface functionalization using a biotin-avidin interaction to improve the nanomicelle's calcification targeting ability. Biotinylated, avidinlyated hydrophobically modified iv glycol chitosan particles were linked to biotinylated alendronate via a strong biotin-avidin linkage. Cyanine 3, a red fluorescent dye was conjugated to the amine groups on HGC for visualization of micelles. The size of the nanoparticles measured was 254.0 +/- 0.43 nm and 209.7 +/- 1.0 nm for Cy3- BHGCA and Cy3-BHGCA-BALN nanoparticles respectively. The average surface charge was measured to be +26.9 +/- 0.19 mV and +27.68 +/- 0.20 mV for Cy3-BHGCA and Cy3-BHGCA- BALN nanoparticles respectively. Binding affinity using hydroxyapatite (HA) revealed that both Cy3 BHGCA BALN and Cy3 BHGCA nanoparticles displayed 95% binding in 24 hours. However, the biotin quenched nanoparticle Cy3 BHGCAB displayed 68% binding in 24 hours. The synthesis and binding chemistry was verified using Fourier transform infrared spectroscopy (FTIR).

Synthesis and electrical properties of polyaniline/iota-carrageenan biocomposites.

PubMed

Vega-Rios, Alejandro; Olmedo-Martínez, Jorge L; Farías-Mancilla, Bárbara; Hernández-Escobar, Claudia A; Zaragoza-Contreras, E Armando

2014-09-22

Polyaniline/iota-carrageenan (ι-CGN) biocomposites were synthesized via in situ methodology using ammonium persulfate as the oxidizing agent. Both ionic (band at 1131 cm(-1)) and hydrogen bond (bands at 2500 and 3500 cm(-1)) interactions between polyaniline and ι-CGN were determined by infrared spectroscopy. Such intermolecular interactions provided the biocomposites with a cross-linked structure that provided the materials with hydrogel behavior. Biocomposite electro-conductivity, determined by the 4-probe technique, was in the range of semiconductors (10(-3) to 10(-2) S cm(-1)); whereas electro-activity, assessed by cyclic voltammetry, showed the oxidation-reduction transitions typical of polyaniline. Based on the properties of polyaniline and ι-CGN, some applications for the new materials in the field of biosensor design, electrochemical capacitors, or tissue engineering scaffolds are possible. It is worth saying that both electro-conductive and electro-active properties of polyaniline/ι-CGN biocomposites are reported here for the first time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Organic Solar Cells Based on Electrodeposited Polyaniline Films

NASA Astrophysics Data System (ADS)

Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

2012-04-01

Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

Glucose biosensor from covalent immobilization of chitosan-coupled carbon nanotubes on polyaniline-modified gold electrode.

PubMed

Wan, Dong; Yuan, Shaojun; Li, G L; Neoh, K G; Kang, E T

2010-11-01

An amperometric glucose biosensor was prepared using polyaniline (PANI) and chitosan-coupled carbon nanotubes (CS-CNTs) as the signal amplifiers and glucose oxidase (GOD) as the glucose detector on a gold electrode (the Au-g-PANI-c-(CS-CNTs)-GOD biosensor). The PANI layer was prepared via oxidative graft polymerization of aniline from the gold electrode surface premodified by self-assembled monolayer of 4-aminothiophenol. CS-CNTs were covalently coupled to the PANI-modified gold substrate using glutaradehyde as a bifunctional linker. GOD was then covalently bonded to the pendant hydroxyl groups of chitosan using 1,4-carbonyldiimidazole as the bifunctional linker. The surface functionalization processes were ascertained by X-ray photoelectron spectroscopy (XPS) analyses. The field emission scanning electron microscopy (FESEM) images of the Au-g-PANI-c-(CS-CNTs) electrode revealed the formation of a three-dimensional surface network structure. The electrode could thus provide a more spatially biocompatible microenvironment to enhance the amount and biocatalytic activity of the immobilized enzyme and to better mediate the electron transfer. The resulting Au-g-PANI-c-(CS-CNTs)-GOD biosensor exhibited a linear response to glucose in the concentration range of 1-20 mM, good sensitivity (21 μA/(mM·cm(2))), good reproducibility, and retention of >80% of the initial response current after 2 months of storage.

Controlled Photocatalytic Synthesis of Core–Shell SiC/Polyaniline Hybrid Nanostructures

PubMed Central

Kormányos, Attila; Endrődi, Balázs; Ondok, Róbert; Sápi, András; Janáky, Csaba

2016-01-01

Hybrid materials of electrically conducting polymers and inorganic semiconductors form an exciting class of functional materials. To fully exploit the potential synergies of the hybrid formation, however, sophisticated synthetic methods are required that allow for the fine-tuning of the nanoscale structure of the organic/inorganic interface. Here we present the photocatalytic deposition of a conducting polymer (polyaniline) on the surface of silicon carbide (SiC) nanoparticles. The polymerization is facilitated on the SiC surface, via the oxidation of the monomer molecules by ultraviolet-visible (UV-vis) light irradiation through the photogenerated holes. The synthesized core–shell nanostructures were characterized by UV-vis, Raman, and Fourier Transformed Infrared (FT-IR) Spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy, and electrochemical methods. It was found that the composition of the hybrids can be varied by simply changing the irradiation time. In addition, we proved the crucial importance of the irradiation wavelength in forming conductive polyaniline, instead of its overoxidized, insulating counterpart. Overall, we conclude that photocatalytic deposition is a promising and versatile approach for the synthesis of conducting polymers with controlled properties on semiconductor surfaces. The presented findings may trigger further studies using photocatalysis as a synthetic strategy to obtain nanoscale hybrid architectures of different semiconductors. PMID:28773325

Construction of a Polyaniline Nanofiber Gas Sensor

ERIC Educational Resources Information Center

Virji, Shabnam; Weiller, Bruce H.; Huang, Jiaxing; Blair, Richard; Shepherd, Heather; Faltens, Tanya; Haussmann, Philip C.; Kaner, Richard B.; Tolbert, Sarah H.

2008-01-01

The electrical properties of polyaniline changes by orders of magnitude upon exposure to analytes such as acids or bases, making it a useful material for detection of these analytes in the gas phase. The objectives of this lab are to synthesize different diameter polyaniline nanofibers and compare them as sensor materials. In this experiment…

Corrosion resistant properties of polyaniline acrylic coating on magnesium alloy

NASA Astrophysics Data System (ADS)

Sathiyanarayanan, S.; Azim, S. Syed; Venkatachari, G.

2006-12-01

The performance of the paint coating based on acrylic-polyaniline on magnesium alloy ZM 21 has been studied by electrochemical impedance spectroscopy in 0.5% NaCl solution. The polyaniline was prepared by chemical oxidative method of aniline with ammonium persulphate in phosphoric acid medium. The phosphate-doped polyaniline was characterized by FTIR and XRD methods. Acrylic paint containing the phosphate-doped polyaniline was prepared and coated on magnesium ZM 21 alloy. The coating was able to protect the magnesium alloy and no base metal dissolution was noted even after 75 days exposure to sodium chloride solution.

Modified surface of titanium dioxide nanoparticles-based biosensor for DNA detection

NASA Astrophysics Data System (ADS)

Nadzirah, Sh.; Hashim, U.; Rusop, M.

2018-05-01

A new technique was used to develop a simple and selective picoammeter DNA biosensor for identification of E. coli O157:H7. This biosensor was fabricated from titanium dioxide nanoparticles that was synthesized by sol-gel method and spin-coated on silicon dioxide substrate via spinner. 3-Aminopropyl triethoxy silane (APTES) was used to modify the surface of TiO2. Simple surface modification approach has been applied; which is single dropping of APTES onto the TiO2 nanoparticles surface. Carboxyl modified probe DNA has been bind onto the surface of APTES/TiO2 without any amplifier element. Electrical signal has been used as the indicator to differentiate each step (surface modification of TiO2 and probe DNA immobilization). The I-V measurements indicate extremely low current (pico-ampere) flow through the device which is 2.8138E-10 A for pure TiO2 nanoparticles, 2.8124E-10 A after APTES modification and 3.5949E-10 A after probe DNA immobilization.

Investigation of electrochemical actuation by polyaniline nanofibers

NASA Astrophysics Data System (ADS)

Mehraeen, Shayan; Alkan Gürsel, Selmiye; Papila, Melih; Çakmak Cebeci, Fevzi

2017-09-01

Polyaniline nanofibers have shown promising electrical and electrochemical properties which make them prominent candidates in the development of smart systems employing sensors and actuators. Their electrochemical actuation potential is demonstrated in this study. A trilayer composite actuator based on polyaniline nanofibers was designed and fabricated. Cross-linked polyvinyl alcohol was sandwiched between two polyaniline nanofibrous electrodes as ion-containing electrolyte gel. First, electrochemical behavior of a single electrode was studied, showing reversible redox peak pairs in 1 M HCl using a cyclic voltammetry technique. High aspect ratio polyaniline nanofibers create a porous network which facilitates ion diffusion and thus accelerates redox reactions. Bending displacement of the prepared trilayer actuator was then tested and reported under an AC potential stimulation as low as 0.5 V in a variety of frequencies from 50 to 1000 mHz, both inside 1 M HCl solution and in air. Decay of performance of the composite actuator in air is investigated and it is reported that tip displacement in a solution was stable and repeatable for 1000 s in all selected frequencies.

A nanostructured graphene/polyaniline hybrid material for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Hualan; Hao, Qingli; Yang, Xujie; Lu, Lude; Wang, Xin

2010-10-01

A flexible graphene/polyaniline hybrid material as a supercapacitor electrode was synthesized by an in situ polymerization-reduction/dedoping-redoping process. This product was first prepared in an ethylene glycol medium, then treated with hot sodium hydroxide solution to obtain the reduced graphene oxide/polyaniline hybrid material. Sodium hydroxide also acted as a dedoping reagent for polyaniline in the composite. After redoping in an acidic solution, the thin, uniform and flexible conducting graphene/polyaniline product was obtained with unchanged morphology. The chemical structure of the materials was characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. The composite material showed better electrochemical performances than the pure individual components. A high specific capacitance of 1126 F g-1 was obtained with a retention life of 84% after 1000 cycles for supercapacitors. The energy density and power density were also better than those of pure component materials.

A nanostructured graphene/polyaniline hybrid material for supercapacitors.

PubMed

Wang, Hualan; Hao, Qingli; Yang, Xujie; Lu, Lude; Wang, Xin

2010-10-01

A flexible graphene/polyaniline hybrid material as a supercapacitor electrode was synthesized by an in situ polymerization-reduction/dedoping-redoping process. This product was first prepared in an ethylene glycol medium, then treated with hot sodium hydroxide solution to obtain the reduced graphene oxide/polyaniline hybrid material. Sodium hydroxide also acted as a dedoping reagent for polyaniline in the composite. After redoping in an acidic solution, the thin, uniform and flexible conducting graphene/polyaniline product was obtained with unchanged morphology. The chemical structure of the materials was characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. The composite material showed better electrochemical performances than the pure individual components. A high specific capacitance of 1126 F g(-1) was obtained with a retention life of 84% after 1000 cycles for supercapacitors. The energy density and power density were also better than those of pure component materials.

New Anti-Corrosive Coatings with Resin-Bonded Polyaniline and Related Electroactive Groups

NASA Technical Reports Server (NTRS)

Weil, Edward D.

1997-01-01

It is already known that polyaniline (an electroactive polymer) functions as a corrosion inhibitor for steel and in view of the fact that it is known to perform in the presence of hydrochloric acid, it has been considered likely that it may be useful to NASA for protecting launch structures at KSC which are exposed to not only continual ocean-side salt spray but also to hydrochloric acid at the times that solid-fuel boosters are fired. The currently used zinc-rich silicate-bonded coating is not wholly protective against the hydrochloric acid. Water pollution from zinc salts is another concern. Other earlier and concurrent NASA sponsored projects have been focussed on polyaniline specifically. Our project, administered for NASA by Dr. K. Thompson of KSC and these more-specifically polyaniline-related projects are included in a CRADA coordinated by Dr. F. Via of Akzo Nobel. A parallel project at Polytechnic under Prof K. Levon concentrated more specifically on polyaniline with various dopants. Our exploratory project reported herein was aimed at broadening the range of such corrosion inhibitors, to give protective paint compounders a wider latitude for adding corrosion inhibitors having polyaniline-like performance, and thus we diverged in several probing directions from polyaniline. Our working hypothesis was that physical variants of polyaniline, such as supported formulations on pigments or carriers, and chemical variants of polyaniline, including those having no electroconductive character, may have enhanced anticorrosion activity. We also hypothesized that small (non-polymeric) molecules having structures related to those occurring in polyaniline, may be active as corrosion inhibitors. We did preliminary testing, using an ASTM salt spray method at a nearby commercial paint testing laboratory. Our most interesting findings were that a non-electroconductive meta-isomer of polyaniline showed some corrosion activity, suggesting that the features of the polyaniline

Hyaluronic acid-modified zirconium phosphate nanoparticles for potential lung cancer therapy.

PubMed

Li, Ranwei; Liu, Tiecheng; Wang, Ke

2017-02-01

Novel tumor-targeting zirconium phosphate (ZP) nanoparticles modified with hyaluronic acid (HA) were developed (HA-ZP), with the aim of combining the drug-loading property of ZP and the tumor-targeting ability of HA to construct a tumor-targeting paclitaxel (PTX) delivery system for potential lung cancer therapy. The experimental results indicated that PTX loading into the HA-ZP nanoparticles was as high as 20.36%±4.37%, which is favorable for cancer therapy. PTX-loaded HA-ZP nanoparticles increased the accumulation of PTX in A549 lung cancer cells via HA-mediated endocytosis and exhibited superior anticancer activity in vitro. In vivo anticancer efficacy assay revealed that HA-ZP nanoparticles possessed preferable anticancer abilities, which exhibited minimized toxic side effects of PTX and strong tumor-suppression potential in clinical application.

Temperature characterization of dielectric permittivity and AC conductivity of nano copper oxide-doped polyaniline composite

NASA Astrophysics Data System (ADS)

Shubha, L. N.; Madhusudana Rao, P.

2016-06-01

The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UV-visible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 102-106Hz using LCR meter. Dielectric permittivity ɛ‧(w) and dielectric loss factor ɛ‧‧(w) were investigated. It was observed that ɛ‧(w) and ɛ‧‧(w) decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both ɛ‧(w) and ɛ‧‧(w) increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

Monodisperse magnetite (Fe3O4) nanoparticles modified with water soluble polymers for the diagnosis of breast cancer by MRI method

NASA Astrophysics Data System (ADS)

Rezayan, Ali Hossein; Mousavi, Majid; Kheirjou, Somayyeh; Amoabediny, Ghasem; Ardestani, Mehdi Shafiee; Mohammadnejad, Javad

2016-12-01

In this study, magnetic nanoparticles (MNPs) were synthesized via co-precipitation method. To enhance the biocompatibility and colloidal stability of the synthesized nanoparticles, they were modified with carboxyl functionalized PEG via dopamine (DPA) linker. Both modified and unmodified Fe3O4 nanoparticles exhibited super paramagnetic behavior (particle size below 20 nm). The saturation magnetization (Ms) of PEGdiacid-modified Fe3O4 was 45 emu/g, which was less than the unmodified Fe3O4 nanoparticles (70 emu/g). This difference indicated that PEGdiacid polymer was immobilized on the surface of Fe3O4 nanoparticles successfully. To evaluate the efficiency of the resulting nanoparticles as contrast agents for magnetic resonance imaging (MRI), different concentration of MNPs and different value of echo time TE were investigated. The results showed that by increasing the concentration of the nanoparticles, transverse relaxation time (T2) decreased, which subsequently resulted in MR signal enhancement. T2-weighted MR images of the different concentration of MNPs in different value of echo time TE indicated that MR signal intensity increased with increase in TE value up to 66 and then remained constant. The cytotoxicity effect of the modified and unmodified nanoparticles was evaluated in three different concentrations (12, 60 and 312 mg l-1) on MDA-MB-231 cancer cells for 24 and 48 h. In both tested time (24 and 48 h) for all three samples, the modified nanoparticles had long life time than unmodified nanoparticles. Cellular uptake of modified MNPs was 80% and reduced to 9% by the unmodified MNPs.

Improving the Thermoelectric Properties of Polyaniline by Introducing Poly(3,4-ethylenedioxythiophene)

NASA Astrophysics Data System (ADS)

Wang, Xiao Yang; Liu, Cheng Yan; Miao, Lei; Gao, Jie; Chen, Yu

2016-03-01

By using the parent monomers, 3,4-ethylenedioxythiophene and aniline, a series of nanocomposites consisting of different mass ratios of polyaniline (PANI) to poly(3,4-ethylenedioxythiophene) (PEDOT) have been successfully prepared in hydrochloric acid solution through oxidative polymerization, then redoped with p-toluenesulfonic acid ( p-TSA). Firstly, PEDOT nanoparticles were fabricated via chemical oxidation polymerization in reverse (water-in-oil) microemulsions. Then, PANI-doped PEDOT nanoparticles were formed by oxidative polymerization of aniline to form PANI/PEDOT nanofibers. The resulting nanostructured components were characterized by scanning electron microscopy (SEM) and a series of spectroscopic methods. The presence of PEDOT increased the room-temperature electrical conductivity of the PANI/PEDOT nanocomposites by more than two orders of magnitude in comparison with the parent PANI. Moreover, the PANI/PEDOT nanocomposites showed better thermoelectric properties than PANI. Different concentrations of p-TSA also affected the electrical conductivity and Seebeck coefficient of the nanocomposites. With increasing temperature, both the electrical conductivity and Seebeck coefficient increased.

Interaction and cellular uptake of surface-modified carbon dot nanoparticles by J774.1 macrophages

PubMed Central

Thoo, Lester; Fahmi, Mochamad Z; Zulkipli, Ihsan N; Keasberry, Natasha

2017-01-01

Carbon dot (Cdot) nanoparticles are an emerging class of carbon nanomaterials with a promising potential for drug delivery and bio imaging applications. Although the interaction between Cdots and non-immune cell types has been well studied, Cdot interactions with macrophages have not been investigated. Exposure of Cdot nanoparticles to J774.1 cells, a murine macrophage cell line, resulted in minimal toxicity, where notable toxicity was only seen with Cdot concentrations higher than 0.5 mg/ml. Flow cytometric analysis revealed that Cdots prepared from citric acid were internalized at significantly higher levels by macrophages compared with those prepared from bamboo leaves. Interestingly, macrophages preferentially took up phenylboronic acid (PB)-modified nanoparticles. By fluorescence microscopy, strong blue light-specific punctate Cdot fluorescence resembling Cdot structures in the cytosolic space was mostly observed in J774.1 macrophages exposed to PB-modified nanoparticles and not unmodified Cdot nanoparticles. PB binds to sialic acid residues that are overexpressed on diseased cell surfaces. Our findings demonstrate that PB-conjugated Cdots can be taken up by macrophages with low toxicity and high efficiency. These modified Cdots can be used to deliver drugs to suppress or eliminate aberrant immune cells such as macrophages associated with tumors such as tumor-associated macrophages. PMID:29204100

Aptamer-modified nanoparticles and their use in cancer diagnostics and treatment.

PubMed

Reinemann, Christine; Strehlitz, Beate

2014-01-06

Aptamers are single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) oligonucleotides, which are able to bind their target with high selectivity and affinity. Owing to their multiple talents, aptamers combined with nanoparticles are nanosystems well qualified for the development of new biomedical devices for analytical, imaging, drug delivery and many other medical applications. Because of their target affinity, aptamers can direct the transport of aptamer-nanoparticle conjugates. The binding of the aptamers to the target "anchors" the nanoparticle-aptamer conjugates at their site of action. In this way, nanoparticle-based bioimaging and smart drug delivery are enabled, especially by use of systematically developed aptamers for cancer-associated biomarkers. This review article gives a brief overview of recent relevant research into aptamers and trends in their use in cancer diagnostics and therapy. A concise description of aptamers, their development and functionalities relating to nanoparticle modification is given. The main part of the article is dedicated to current developments of aptamer-modified nanoparticles and their use in cancer diagnostics and treatment.

Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.

PubMed

Krpetić, Zeljka; Saleemi, Samia; Prior, Ian A; Sée, Violaine; Qureshi, Rumana; Brust, Mathias

2011-06-28

This paper contributes to the debate on how nanosized objects negotiate membrane barriers inside biological cells. The uptake of peptide-modified gold nanoparticles by HeLa cells has been quantified using atomic emission spectroscopy. The TAT peptide from the HIV virus was singled out as a particularly effective promoter of cellular uptake. The evolution of the intracellular distribution of TAT-modified gold nanoparticles with time has been studied in detail by TEM and systematic image analysis. An unusual trend of particles disappearing from the cytosol and the nucleus and accumulating massively in vesicular bodies was observed. Subsequent release of the particles, both by membrane rupture and by direct transfer across the membrane boundary, was frequently found. Ultimately, near total clearing of particles from the cells occurred. This work provides support for the hypothesis that cell-penetrating peptides can enable small objects to negotiate membrane barriers also in the absence of dedicated transport mechanisms.

Polyelectrolyte-modified cowpea mosaic virus for the synthesis of gold nanoparticles.

PubMed

Aljabali, Alaa A A; Evans, David J

2014-01-01

Polyelectrolyte surface-modified cowpea mosaic virus (CPMV) can be used for the templated synthesis of narrowly dispersed gold nanoparticles. Cationic polyelectrolyte, poly(allylamine) hydrochloride, is electrostatically bound to the external surface of the virus capsid. The polyelectrolyte-coated CPMV promotes adsorption of aqueous gold hydroxide anionic species, prepared from gold(III) chloride and potassium carbonate, that are easily reduced to form CPMV-templated gold nanoparticles. The process is simple and environmentally benign using only water as solvent at ambient temperature.

Effect of Surface-Modified TiO2 Nanoparticles on the Anti-Ultraviolet Aging Performance of Foamed Wheat Straw Fiber/Polypropylene Composites

PubMed Central

Xuan, Lihui; Han, Guangping; Wang, Dong; Cheng, Wanli; Gao, Xun; Chen, Feng; Li, Qingde

2017-01-01

Surface modification and characterization of titanium dioxide (TiO2) nanoparticles and their roles in thermal, mechanical, and accelerated aging behavior of foamed wheat straw fiber/polypropylene (PP) composites are investigated. To improve the dispersion of nanoparticles and increase the possible interactions between wheat straw fiber and the PP matrix, the surface of the TiO2 nanoparticles was modified with ethenyltrimethoxy silane (A171), a silane coupling agent. The grafting of A171 on the TiO2 nanoparticles’ surface was characterized by Fourier transform infrared spectroscopy (FTIR). The wheat straw fibers treated with A171 and modified TiO2 nanoparticles were characterized by FTIR and thermogravimetric analysis (TGA). FTIR spectra confirmed that the organic functional groups of A171 were successfully grafted onto the TiO2 nanoparticles and wheat straw fibers, and the modified TiO2 nanoparticles were adsorbed onto the wheat straw fibers. Thermogravimetric analysis showed that a higher thermal stability of the wheat straw fiber was obtained with the modified TiO2 nanoparticles. The flexural, tensile, and impact properties were improved. A higher ultraviolet (UV) stability of the samples treated with modified TiO2 nanoparticles was exhibited by the study of the color change and loss in mechanical properties. PMID:28772816

Heavy-metal detectors based on modified ferrite nanoparticles

PubMed Central

Klekotka, Urszula; Wińska, Ewelina; Zambrzycka-Szelewa, Elżbieta; Satuła, Dariusz

2018-01-01

In this work, we analyze artificial heavy-metal solutions with ferrite nanoparticles. Measurements of adsorption effectiveness of different kinds of particles, pure magnetite or magnetite doped with calcium, cobalt, manganese, or nickel ions, were carried out. A dependence of the adsorption efficiency on the composition of the inorganic core has been observed. Ferrites surfaces were modified by phthalic anhydride (PA), succinic anhydride (SA), acetic anhydride (AA), 3-phosphonopropionic acid (3-PPA), or 16-phosphohexadecanoic acid (16-PHDA) to compare the adsorption capability of the heavy metals Cd, Cu and Pb. The obtained nanoparticles were structurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The amounts of Cd, Cu and Pb were measured out by atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) as comparative techniques. The performed study shows that SA linker appears to be the most effective in the adsorption of heavy metals. Moreover, regarding the influence of the composition of the inorganic core on the detection ability, the most effective ferrite Mn0.5Fe2.5O4 was selected for discussion. The highest heavy-metal adsorption capability and universality was observed for SA as a surface modifier. PMID:29600137

Heavy-metal detectors based on modified ferrite nanoparticles.

PubMed

Klekotka, Urszula; Wińska, Ewelina; Zambrzycka-Szelewa, Elżbieta; Satuła, Dariusz; Kalska-Szostko, Beata

2018-01-01

In this work, we analyze artificial heavy-metal solutions with ferrite nanoparticles. Measurements of adsorption effectiveness of different kinds of particles, pure magnetite or magnetite doped with calcium, cobalt, manganese, or nickel ions, were carried out. A dependence of the adsorption efficiency on the composition of the inorganic core has been observed. Ferrites surfaces were modified by phthalic anhydride (PA), succinic anhydride (SA), acetic anhydride (AA), 3-phosphonopropionic acid (3-PPA), or 16-phosphohexadecanoic acid (16-PHDA) to compare the adsorption capability of the heavy metals Cd, Cu and Pb. The obtained nanoparticles were structurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The amounts of Cd, Cu and Pb were measured out by atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) as comparative techniques. The performed study shows that SA linker appears to be the most effective in the adsorption of heavy metals. Moreover, regarding the influence of the composition of the inorganic core on the detection ability, the most effective ferrite Mn 0.5 Fe 2.5 O 4 was selected for discussion. The highest heavy-metal adsorption capability and universality was observed for SA as a surface modifier.

Raman gas sensing of modified Ag nanoparticle SERS

NASA Astrophysics Data System (ADS)

Myoung, NoSoung; Yoo, Hyung Keun; Hwang, In-Wook

2014-03-01

Recent progress in modified Surface Enhanced Raman Scattering (SERS) using Ag nanoparticles makes them promising optical technique for direct gas sensing of interest. However, SERS has been shown to provide sub ppb level detection of the compounds in the vapor phase. The major problem with the sensitivity scaling-up was in the development of fabrication technology for stability and reproducibility of SERS substrates. We report an optimization of 1-propanethiol coated multiple Ag nanoparticle layers on SiO2 substrate as well as new records of real-time, simultaneous vapor phase detection of toluene and 1-2 dichlorobenzene by the radiation of fiber optic coupled 785 nm diode laser and spectrograph. Multiple depositions of Ag NPs were loaded on SiO2 and soaked in 1-propanethiol solution for 24 hours to modify the surface into hydrophobic due to the characteristics of vapor phase of our interests. Raman bands at 1003 cm-1 and 1130 cm-1 for toluene and 12DCB, respectively were compared to 1089 cm-1 and each gas concentration in 1000 mL flask were calculated as a function of each vapor phase ratio. The saturation of toluene and 12DCB were limited only by 800 ppm and the detectable range was 0.6-800 ppm.

Apparently enhanced magnetization of Cu(I)-modified γ-Fe2O3 based nanoparticles

NASA Astrophysics Data System (ADS)

Qiu, Xiaoyan; He, Zhenghong; Mao, Hong; Zhang, Ting; Lin, Yueqiang; Liu, Xiaodong; Li, Decai; Meng, Xiangshen; Li, Jian

2017-11-01

Using a chemically induced transition method in FeCl2 solution, γ-Fe2O3 based magnetic nanoparticles, in which γ-Fe2O3 crystallites were coated with FeCl3ṡ6H2O, were prepared. During the synthesis of the γ-Fe2O3 nanoparticles Cu(I) modification of the particles was attempted. According to the results from both magnetization measurements and structural characterization, it was judged that a magnetic silent "dead layer", which can be attributed to spin disorder in the surface of the γ-Fe2O3 crystallites due to breaking of the crystal symmetry, existed in the unmodified particles. For the Cu(I)-modified sample, the CuCl thin layer on the γ-Fe2O3 crystallites incurred the crystal symmetry to reduce the spin disorder, which "awakened" the "dead layer" on the surface of the γ-Fe2O3 crystallites, enhancing the apparent magnetization of the Cu(I)-modified nanoparticles. It was determined that the surface spin disorder of the magnetic crystallite could be related to the coating layer on the crystallite, and can be modified by altering the coating layer to enhance the effective magnetization of the magnetic nanoparticles.

Covalent immobilization of invertase on PAMAM-dendrimer modified superparamagnetic iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Uzun, K.; Çevik, E.; Şenel, M.; Sözeri, H.; Baykal, A.; Abasıyanık, M. F.; Toprak, M. S.

2010-10-01

In this study, polyamidoamine (PAMAM) dendrimer was synthesized on the surface of superparamagnetite nanoparticles to enhance invertase immobilization. The amount of immobilized enzyme on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times (i.e., 250%) as much as that of magnetite nanoparticle modified with only amino silane. Maximum reaction rate ( V max) and Michaelis-Menten constant ( K m) were determined for the free and immobilized enzymes. Various characteristics of immobilized invertase such as; the temperature activity, thermal stability, operational stability, and storage stability were evaluated and results revealed that stability of the enzyme is improved upon immobilization.

Enhanced intracellular delivery and controlled drug release of magnetic PLGA nanoparticles modified with transferrin.

PubMed

Cui, Yan-Na; Xu, Qing-Xing; Davoodi, Pooya; Wang, De-Ping; Wang, Chi-Hwa

2017-06-01

Owing to the presence of multidrug resistance in tumor cells, conventional chemotherapy remains clinically intractable. To enhance the therapeutic efficacy of chemotherapeutic agents, targeting strategies based on magnetic polymeric nanoparticles modified with targeting ligands have gained significant attention in cancer therapy. In this study, we synthesized transferrin (Tf)-modified poly(D,L-lactic-co-glycolic acid) nanoparticles (PLGA NPs) loaded with paclitaxel (PTX) and superparamagnetic nanoparticle (MNP) using a solid-in-oil-in-water solvent evaporation method, followed by Tf adsorption on the surface of NPs. The Tf-modified magnetic PLGA NPs were characterized in terms of particle morphology and size, magnetic properties, encapsulation efficiency and drug release. Furthermore, the cytotoxicity and cellular uptake of the drug-loaded magnetic PLGA NPs were evaluated in both MCF-7 breast cancer and U-87 glioma cells in vitro. We found that Tf-modified PTX-MNP-PLGA NPs showed the highest cytotoxicity effect and cellular uptake efficiency under Tf receptor mediation in both MCF-7 and U-87 cells compared to unmodified PLGA NPs and free PTX. The cellular uptake efficiency of Tf-modified magnetic PLGA NPs appeared to be facilitated by the applied magnetic field, but the difference did not reach statistical significance. This study illustrates that this proposed formulation can be used as one new alternative treatment for patients bearing inaccessible tumors.

Enhanced intracellular delivery and controlled drug release of magnetic PLGA nanoparticles modified with transferrin

PubMed Central

Cui, Yan-na; Xu, Qing-xing; Davoodi, Pooya; Wang, De-ping; Wang, Chi-Hwa

2017-01-01

Owing to the presence of multidrug resistance in tumor cells, conventional chemotherapy remains clinically intractable. To enhance the therapeutic efficacy of chemotherapeutic agents, targeting strategies based on magnetic polymeric nanoparticles modified with targeting ligands have gained significant attention in cancer therapy. In this study, we synthesized transferrin (Tf)-modified poly(D,L-lactic-co-glycolic acid) nanoparticles (PLGA NPs) loaded with paclitaxel (PTX) and superparamagnetic nanoparticle (MNP) using a solid-in-oil-in-water solvent evaporation method, followed by Tf adsorption on the surface of NPs. The Tf-modified magnetic PLGA NPs were characterized in terms of particle morphology and size, magnetic properties, encapsulation efficiency and drug release. Furthermore, the cytotoxicity and cellular uptake of the drug-loaded magnetic PLGA NPs were evaluated in both MCF-7 breast cancer and U-87 glioma cells in vitro. We found that Tf-modified PTX-MNP-PLGA NPs showed the highest cytotoxicity effect and cellular uptake efficiency under Tf receptor mediation in both MCF-7 and U-87 cells compared to unmodified PLGA NPs and free PTX. The cellular uptake efficiency of Tf-modified magnetic PLGA NPs appeared to be facilitated by the applied magnetic field, but the difference did not reach statistical significance. This study illustrates that this proposed formulation can be used as one new alternative treatment for patients bearing inaccessible tumors. PMID:28552909

Uptake Mechanism of ApoE-Modified Nanoparticles on Brain Capillary Endothelial Cells as a Blood-Brain Barrier Model

PubMed Central

Wagner, Sylvia; Zensi, Anja; Wien, Sascha L.; Tschickardt, Sabrina E.; Maier, Wladislaw; Vogel, Tikva; Worek, Franz; Pietrzik, Claus U.; Kreuter, Jörg; von Briesen, Hagen

2012-01-01

Background The blood-brain barrier (BBB) represents an insurmountable obstacle for most drugs thus obstructing an effective treatment of many brain diseases. One solution for overcoming this barrier is a transport by binding of these drugs to surface-modified nanoparticles. Especially apolipoprotein E (ApoE) appears to play a major role in the nanoparticle-mediated drug transport across the BBB. However, at present the underlying mechanism is incompletely understood. Methodology/Principal Findings In this study, the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells was investigated to differentiate between active and passive uptake mechanism by flow cytometry and confocal laser scanning microscopy. Furthermore, different in vitro co-incubation experiments were performed with competing ligands of the respective receptor. Conclusions/Significance This study confirms an active endocytotic uptake mechanism and shows the involvement of low density lipoprotein receptor family members, notably the low density lipoprotein receptor related protein, on the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells. This knowledge of the uptake mechanism of ApoE-modified nanoparticles enables future developments to rationally create very specific and effective carriers to overcome the blood-brain barrier. PMID:22396775

Uptake mechanism of ApoE-modified nanoparticles on brain capillary endothelial cells as a blood-brain barrier model.

PubMed

Wagner, Sylvia; Zensi, Anja; Wien, Sascha L; Tschickardt, Sabrina E; Maier, Wladislaw; Vogel, Tikva; Worek, Franz; Pietrzik, Claus U; Kreuter, Jörg; von Briesen, Hagen

2012-01-01

The blood-brain barrier (BBB) represents an insurmountable obstacle for most drugs thus obstructing an effective treatment of many brain diseases. One solution for overcoming this barrier is a transport by binding of these drugs to surface-modified nanoparticles. Especially apolipoprotein E (ApoE) appears to play a major role in the nanoparticle-mediated drug transport across the BBB. However, at present the underlying mechanism is incompletely understood. In this study, the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells was investigated to differentiate between active and passive uptake mechanism by flow cytometry and confocal laser scanning microscopy. Furthermore, different in vitro co-incubation experiments were performed with competing ligands of the respective receptor. This study confirms an active endocytotic uptake mechanism and shows the involvement of low density lipoprotein receptor family members, notably the low density lipoprotein receptor related protein, on the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells. This knowledge of the uptake mechanism of ApoE-modified nanoparticles enables future developments to rationally create very specific and effective carriers to overcome the blood-brain barrier.

A sustained release formulation of chitosan modified PLCL:poloxamer blend nanoparticles loaded with optical agent for animal imaging

NASA Astrophysics Data System (ADS)

Ranjan, Amalendu P.; Zeglam, Karim; Mukerjee, Anindita; Thamake, Sanjay; Vishwanatha, Jamboor K.

2011-07-01

The objective of this study was to develop optical imaging agent loaded biodegradable nanoparticles with indocynanine green (ICG) using chitosan modified poly(L-lactide-co-epsilon-caprolactone) (PLCL):poloxamer (Pluronic F68) blended polymer. Nanoparticles were formulated with an emulsification solvent diffusion technique using PLCL and poloxamer as blend-polymers. Polyvinyl alcohol (PVA) and chitosan were used as stabilizers. The particle size, shape and zeta potential of the formulated nanoparticles and the release kinetics of ICG from these nanoparticles were determined. Further, biodistribution of these nanoparticles was studied in mice at various time points until 24 h following intravenous administration, using a non-invasive imaging system. The average particle size of the nanoparticles was found to be 146 ± 3.7 to 260 ± 4.5 nm. The zeta potential progressively increased from - 41.6 to + 25.3 mV with increasing amounts of chitosan. Particle size and shape of the nanoparticles were studied using transmission electron microscopy (TEM) which revealed the particles to be smooth and spherical in shape. These nanoparticles were efficiently delivered to the cytoplasm of the cells, as observed in prostate and breast cancer cells using confocal laser scanning microscopy. In vitro release studies indicated sustained release of ICG from the nanoparticles over a period of seven days. Nanoparticle distribution results in mice showing improved uptake and accumulation with chitosan modified nanoparticles in various organs and slower clearance at different time points over a 24 h period as compared to unmodified nanoparticles. The successful formulation of such cationically modified nanoparticles for encapsulating optical agents may lead to a potential deep tissue imaging technique for tumor detection, diagnosis and therapy.

Synthesis and electrochemical properties of polyaniline nanofibers by interfacial polymerization.

PubMed

Manuel, James; Ahn, Jou-Hyeon; Kim, Dul-Sun; Ahn, Hyo-Jun; Kim, Ki-Won; Kim, Jae-Kwang; Jacobsson, Per

2012-04-01

Polyaniline nanofibers were prepared by interfacial polymerization with different organic solvents such as chloroform and carbon tetrachloride. Field emission scanning electron microscopy and transmission electron microscopy were used to study the morphological properties of polyaniline nanofibers. Chemical characterization was carried out using Fourier transform infrared spectroscopy, UV-Vis spectroscopy, and X-ray diffraction spectroscopy and surface area was measured using BET isotherm. Polyaniline nanofibers doped with lithium hexafluorophosphate were prepared and their electrochemical properties were evaluated.

Polyaniline silver nanoparticle coffee waste extracted porous graphene oxide nanocomposite structures as novel electrode material for rechargeable batteries

NASA Astrophysics Data System (ADS)

Sundriyal, Poonam; Bhattacharya, Shantanu

2017-03-01

The exploration of new and advanced electrode materials are required in electronic and electrical devices for power storage applications. Also, there has been a continuous endeavour to formulate strategies for extraction of high performance electrode materials from naturally obtained waste products. In this work, we have developed an in situ hybrid nanocomposite from coffee waste extracted porous graphene oxide (CEPG), polyaniline (PANI) and silver nanoparticles (Ag) and have found this novel composite to serve as an efficient electrode material for batteries. The successful interaction among the three phases of the nano-composite i.e. CEPG-PANI-Ag have been thoroughly understood through RAMAN, Fourier transform infrared and x-ray diffraction spectroscopy, morphological studies through field emission scanning electron microscope and transmission electron microscope. Thermo-gravimetric analysis of the nano-composite demonstrates higher thermal stability up-to a temperature of 495 °C. Further BET studies through nitrogen adsorption-desorption isotherms confirm the presence of micro/meso and macro-pores in the nanocomposite sample. The cyclic-voltammetry (CV) analysis performed on CEPG-PANI-Ag nanocomposite exhibits a purely faradic behaviour using nickel foam as a current collector thus suggests the prepared nanocomposite as a battery electrode material. The nanocomposite reports a maximum specific capacity of 1428 C g-1 and excellent cyclic stability up-to 5000 cycles.

Modified Polymeric Nanoparticles Exert In Vitro Antimicrobial Activity Against Oral Bacteria.

PubMed

Toledano-Osorio, Manuel; Babu, Jegdish P; Osorio, Raquel; Medina-Castillo, Antonio L; García-Godoy, Franklin; Toledano, Manuel

2018-06-14

Polymeric nanoparticles were modified to exert antimicrobial activity against oral bacteria. Nanoparticles were loaded with calcium, zinc and doxycycline. Ions and doxycycline release were measured by inductively coupled plasma optical emission spectrometer and high performance liquid chromatography. Porphyromonas gingivalis , Lactobacillus lactis , Streptoccocus mutans , gordonii and sobrinus were grown and the number of bacteria was determined by optical density. Nanoparticles were suspended in phosphate-buffered saline (PBS) at 10, 1 and 0.1 mg/mL and incubated with 1.0 mL of each bacterial suspension for 3, 12, and 24 h. The bacterial viability was assessed by determining their ability to cleave the tetrazolium salt to a formazan dye. Data were analyzed by ANOVA and Scheffe’s F ( p < 0.05). Doxycycline doping efficacy was 70%. A burst liberation effect was produced during the first 7 days. After 21 days, a sustained release above 6 µg/mL, was observed. Calcium and zinc liberation were about 1 and 0.02 µg/mL respectively. The most effective antibacterial material was found to be the Dox-Nanoparticles (60% to 99% reduction) followed by Ca-Nanoparticles or Zn-Nanoparticles (30% to 70% reduction) and finally the non-doped nanoparticles (7% to 35% reduction). P. gingivalis , S. mutans and L. lactis were the most susceptible bacteria, being S. gordonii and S. sobrinus the most resistant to the tested nanoparticles.

Facile fabrication of superparamagnetic graphene/polyaniline/Fe3O4 nanocomposites for fast magnetic separation and efficient removal of dye.

PubMed

Mu, Bin; Tang, Jie; Zhang, Long; Wang, Aiqin

2017-07-13

Using graphene as adsorbent for removal of pollutants from polluted water is commonly recognized to be costly because the graphene is usually produced by a very complex process. Herein, a simple and eco-friendly method was employed to fabricate efficient superparamagnetic graphene/polyaniline/Fe 3 O 4 nanocomposites for removal of dyes. The exfoliation of graphite as nanosheets and the functionalization of nanosheets with polyaniline and Fe 3 O 4 nanoparticles were simultaneously achieved via a one-pot reaction process combining the intercalation polymerization of aniline and the co-precipitation of the residual Fe 3+ and the generated Fe 2+ . The obtained graphene/polyaniline/Fe 3 O 4 nanocomposites exhibited excellent adsorption performance for Congo red, even in the presence of Brilliant green. The adsorption kinetics and adsorption isotherms were well fitted with pseudo second-order kinetic model and Langmuir isotherm model, respectively. In a word, this method is simple and industrially feasible, which provides a new approach to fabricate highly efficient graphene-based adsorbents on large scale for removal of dyes. In addition, it also can be used to exfoliate other two-dimensional materials, such as boron nitride, carbon nitride and MoS 2 for a range of possible applications.

Preparation and electrochemical properties of polyaniline nanofibers using ultrasonication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manuel, James; Kim, Miso; Fapyane, Deby

2014-10-15

Highlights: • Nanofibrous structured polyaniline (PANI) was prepared by simple ultrasonication. • PANI nanofibers prepared at 5 °C are uniform with an average diameter of 50 nm. • The conductivity is increased by 2 × 10{sup 8} times after doping with LiClO{sub 4}. • The cell with PANI-LiClO{sub 4} shows good cycle performance at high current densities. - Abstract: Polyaniline nanofibers have been successfully prepared by applying ultrasonic irradiation during oxidative polymerization of aniline in dilute hydrochloric acid and evaluated for suitability in lithium cells after doping with lithium perchlorate salt. Polyaniline nanofibers are confirmed by Fourier transform infrared spectroscopy,more » Fourier transform Raman spectroscopy, and transmission electron microscopy, and the efficiency of doping is confirmed by DC conductivity measurements at different temperatures. Electrochemical properties of nanofibers are evaluated, of which a remarkable increase in cycle stability is achieved when compared to polyaniline prepared by simple oxidative polymerization of aniline. The cell with nanofibrous polyaniline doped with LiClO{sub 4} delivers an initial discharge capacity value of 86 mA h g{sup −1} at 1 C-rate which is about 60% of theoretical capacity, and the capacity is slightly lowered during cycle and reaches 50% of theoretical capacity after 40 cycles. The cell delivers a stable and higher discharge capacity even at 2 C-rate compared to that of the cell prepared with bulk polyaniline doped with LiClO{sub 4}.« less

Acute and subchronic toxicity analysis of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles.

PubMed

Venkatasubbu, Gopinath Devanand; Ramasamy, S; Gaddam, Pramod Reddy; Kumar, J

2015-01-01

Nanoparticles are widely used for targeted drug delivery applications. Surface modification with appropriate polymer and ligands is carried out to target the drug to the affected area. Toxicity analysis is carried out to evaluate the safety of the surface modified nanoparticles. In this study, paclitaxel attached, folic acid functionalized, polyethylene glycol modified hydroxyapatite and titanium dioxide nanoparticles were used for targeted drug delivery system. The toxicological behavior of the system was studied in vivo in rats and mice. Acute and subchronic studies were carried out. Biochemical, hematological, and histopathological analysis was also done. There were no significant alterations in the biochemical parameters at a low dosage. There was a small change in alkaline phosphatase (ALP) level at a high dosage. The results indicate a safe toxicological profile.

Enhancement of the performance of cadmium sulfide quantum dot solar cells using a platinum-polyaniline counter electrode and a silver nanoparticle-sensitized photoanode

NASA Astrophysics Data System (ADS)

Nourolahi, Hamzeh; Bolorizadeh, Mohammadagha A.; Dorri, Navid; Behjat, Abbas

2017-07-01

A metal-polymer nanocomposite of platinum-polyaniline (Pt/PANI) was deposited on fluorine-doped tin oxide glass substrates to function as a counter electrode for polysulfide redox reactions in cadmium sulfide quantum dot-sensitized solar cells. In addition, front-side illuminated photoelectrodes were sensitized by silver (Ag) nanoparticles (NPs) as an interfacial layer between a transparent conducting oxide substrate and a TiO2 layer. This configuration, i.e., both the Pt/PANI counter electrode and the Ag NPs in the photoanode, leads to 1.92% in the power-conversion efficiency (PCE) of the fabricated cells. A PCE enhancement of around 21% was obtained for the Ag NPs-sensitized photoanodes, as compared with the Ag NPs-free one. The improved performance can be attributed to the easier transport of excited electrons and the inhibition of charge recombination due to the application of an Ag NPs layer. Electrochemical impedance spectroscopy measurements showed that once Ag NPs are incorporated in a photoanode, electron transport time decreases in the photoanode structure.

Heterogeneous enantioselective hydrogenation of beta-keto esters using chirally modified supported Ni nanoparticles

NASA Astrophysics Data System (ADS)

Acharya, Sushma

Enantioselective heterogeneous catalysis is an important and rapidly expanding research area. The two most heavily researched examples of this type of catalysis are the enantioselective hydrogenation of α-keto-esters over Pt-based catalysts and the enantioselective hydrogenation of β-keto-esters over Ni-based catalysts. These enantioselective surface reactions are controlled by the presence of adsorbed chiral molecules i.e. tartaric acid on the surface of the metal component of the catalyst. The work presented in this thesis focuses on two parts, the synthesis of pure nickel nanoparticles and enantioselective behavior of the modified nickel nanoparticles. The works on the synthesis of pure nickel nanoparticles were carried out using two methods, the reverse microemulsion and the reduction method. It was discovered that the reverse microemulsion method produced nickel oxide nanoparticles, whereas the reduction method produced pure nickel nanoparticles. Chiral modifications of Raney nickel (RNi) and C-supported catalysts were studied. The catalysts were employed in enantioselective hydrogenation of methyl acetoacetate (MAA) to (R) - and (S)-enantiomers of methyl 3-hydroxybutyrate (MHB). The effects of modification and hydrogenation parameters such as concentration of modifier temperature, pressure and solvent on the enantioselectivity of MAA hydrogenation were discussed. For RNi methanol was found to be the best solvent, with tartaric acid concentration 0.2 mol/L for achieving the highest enantiomeric excess under 8 bar at 70 oC. Characteristic features of the in-situ modification of Raney nickel and C-supported Ni were also evaluated and the results obtained were compared with the conventional (pre-modification) approach. Parameters for the conventional and in-situ methods were optimised in a series of experiments for both types of catalysts. The in-situ modified catalyst was found more active for both RNi and C-supported catalysts with 98 % and 42% enantiomeric

Hydrophobically modified polysaccharide-based on polysialic acid nanoparticles as carriers for anticancer drugs.

PubMed

Jung, Bom; Shim, Man-Kyu; Park, Min-Ju; Jang, Eun Hyang; Yoon, Hong Yeol; Kim, Kwangmeyung; Kim, Jong-Ho

2017-03-30

This study presented the development of hydrophobically modified polysialic acid (HPSA) nanoparticles, a novel anticancer drug nanocarrier that increases therapeutic efficacy without causing nonspecific toxicity towards normal cells. HPSA nanoparticles were prepared by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS) coupling between N-deacetylated polysialic acid (PSA) and 5β-cholanic acid. The physicochemical characteristics of HPSA nanoparticles (zeta-potential, morphology and size) were measured, and in vitro cytotoxicity and cellular uptake of PSA and HPSA nanoparticles were tested in A549 cells. In vivo cancer targeting of HPSA nanoparticles was evaluated by labeling PSA and HPSA nanoparticles with Cy5.5, a near-infrared fluorescent dye, for imaging. HPSA nanoparticles showed improved cancer-targeting ability compared with PSA. Doxorubicin-loaded HPSA (DOX-HPSA) nanoparticles were prepared using a simple dialysis method. An analysis of the in vitro drug-release profile and drug-delivery behavior showed that DOX was effectively released from DOX-HPSA nanoparticles. In vivo cancer therapy with DOX-HPSA nanoparticles in mice showed antitumor effects that resembled those of free DOX. Moreover, DOX-HPSA nanoparticles had low toxicity toward other organs, reflecting their tumor-targeting property. Hence, HPSA nanoparticles are considered a potential nanocarrier for anticancer agents. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyaniline particles: Material properties when synthesized with aqueous nonionic micelles and environmental stability

NASA Astrophysics Data System (ADS)

Hobaica, Stephen Charles

Polyaniline is a member of the class of electrically conducting polymers, which have possible commercial applications as anticorrosive or static charge removal coatings. Aqueous-based polyaniline coatings are preferred over organic solvent or strong acid based coatings because the water used in these coatings does not pollute the environment. The overall goal of this dissertation was to further the development of useful water-based polyaniline coatings by studying new methods of synthesizing polyaniline particles for water-based coatings, to investigate the material properties of these particles such as molecular weight, electrical conductivity, particle size distribution, and stability of polyaniline in air and water. One method of polymerizing polyaniline for aqueous-based coatings uses micelles, which are composed of a cluster of amphiphile surfactants. Micelles can change the local environment by aligning and absorbing the monomer, and may yield polymers with improved material properties and reaction rates. Nonionic micelles have not been extensively investigated. Therefore the first specific goal of this work was to use an aqueous nonionic micelle solution of nonylphenoxypoly(ethyleneoxy) ethanol surfactant (NP-30 surfactant) to comprehensively investigate a one step chemical polymerization of polyaniline conducted at -3°C, in 1.25 M HCl, with ammonium peroxydisulfate oxidizer. The results show that increasing surfactant concentrations caused a decrease in molecular weight, electrical conductivity and sharper particle size distribution of the polymer. The second specific objective of this dissertation was to determine the effect of water and air on polyaniline. The results showed no degradation of molecular weight, a decrease in chloride and hydrogen composition, and decrease in electrical conductivity for polyaniline immersed in water for extended periods. A chloride ion diffusion coefficient of 2.5 to 74 x 10-9 cm2/hour was measured. The aging of

Phase-Separated Polyaniline/Graphene Composite Electrodes for High-Rate Electrochemical Supercapacitors.

PubMed

Wu, Jifeng; Zhang, Qin'e; Zhou, An'an; Huang, Zhifeng; Bai, Hua; Li, Lei

2016-12-01

Polyaniline/graphene hydrogel composites with a macroscopically phase-separated structure are prepared. The composites show high specific capacitance and excellent rate performance. Further investigation demonstrates that polyaniline inside the graphene hydrogel has low rate performance, thus a phase-separated structure, in which polyaniline is mainly outside the graphene hydrogel matrix, can enhance the rate performance of the composites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of in-vitro cytotoxicity and cellular uptake efficiency of zidovudine-loaded solid lipid nanoparticles modified with Aloe Vera in glioma cells.

PubMed

K S, Joshy; Sharma, Chandra P; Kalarikkal, Nandakumar; Sandeep, K; Thomas, Sabu; Pothen, Laly A

2016-09-01

Zidovudine loaded solid lipid nanoparticles of stearic acid modified with Aloe Vera (AV) have been prepared via simple emulsion solvent evaporation method which showed excellent stability at room temperature and refrigerated condition. The nanoparticles were examined by Fourier transform infrared spectroscopy (FT-IR), which revealed the overlap of the AV absorption peak with the absorption peak of modified stearic acid nanoparticles. The inclusion of AV to stearic acid decreased the crystallinity and improved the hydrophilicity of lipid nanoparticles and thereby improved the drug loading efficacy of lipid nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging revealed that, the average particle size of unmodified (bare) nanoparticles was 45.66±12.22nm and modified solid lipid nanoparticles showed an average size of 265.61±80.44nm. Solid lipid nanoparticles with well-defined morphology were tested in vitro for their possible application in drug delivery. Cell culture studies using C6 glioma cells on the nanoparticles showed enhanced growth and proliferation of cells without exhibiting any toxicity. In addition, normal cell morphology and improved uptake were observed by fluorescence microscopy images of rhodamine labeled modified solid lipid nanoparticles compared with unmodified nanoparticles. The cellular uptake study suggested that these nanoparticles could be a promising drug delivery system to enhance the uptake of antiviral drug by brain cells and it could be a suitable drug carrier system for the treatment of HIV. Copyright © 2016 Elsevier B.V. All rights reserved.

Biopolymer stabilized water dispersible polyaniline for supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Anbalagan, Amarnath Chellachamy; Sawant, Shilpa Nandkishor

2018-04-01

Polyaniline colloidal nanoparticles (PANI CNs) were synthesized, employing biopolymer pectin (Pec) as a stabilizer along with hydrochloric acid dopant and ammonium persulfate oxidant. Chemical nature and electronic structure was studied by FT-IR and UV-visible spectroscopy respectively. FE-SEM revealed spindle like morphology of PANI CNs and displayed the nearly discrete particles without aggregation, showing stabilizing capacity of the Pec. Cyclic voltammetry and galvanostatic charge-discharge measurements demonstrated the electroactivity and supercapacitive property of the PANI CNs in 1 M HCl. The specific capacitance of PANI CNs in 1 M HCl at 1.5 A/g was found to be 197 F/g, where 70% of specific capacitance was retained even after 1000 cycles. These findings establish the feasibility of using the PANI CNs as a potential material for energy storage in aqueous acidic medium. Furthermore, this colloidal dispersion can find potential application in electrodes of flexible supercapacitor device and printable electronics.

Acute and subchronic toxicity analysis of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles

PubMed Central

Venkatasubbu, Gopinath Devanand; Ramasamy, S; Gaddam, Pramod Reddy; Kumar, J

2015-01-01

Nanoparticles are widely used for targeted drug delivery applications. Surface modification with appropriate polymer and ligands is carried out to target the drug to the affected area. Toxicity analysis is carried out to evaluate the safety of the surface modified nanoparticles. In this study, paclitaxel attached, folic acid functionalized, polyethylene glycol modified hydroxyapatite and titanium dioxide nanoparticles were used for targeted drug delivery system. The toxicological behavior of the system was studied in vivo in rats and mice. Acute and subchronic studies were carried out. Biochemical, hematological, and histopathological analysis was also done. There were no significant alterations in the biochemical parameters at a low dosage. There was a small change in alkaline phosphatase (ALP) level at a high dosage. The results indicate a safe toxicological profile. PMID:26491315

Design and preparation of bi-functionalized short-chain modified zwitterionic nanoparticles.

PubMed

Hu, Fenglin; Chen, Kaimin; Xu, Hong; Gu, Hongchen

2018-05-01

(FBS). The modified nanoparticles can also be successfully functionalized with a specific antibody for CLEIA assay with a prominent bio-detection performance even in 50% FBS. In this paper, we also investigated an unexpectedly fast hydrolysis behavior of NHS-activated carboxylic groups within the pure short-chain zwitterionic molecule that led to no protein binding in the short-chain zwitterion modified nanoparticle. Our findings pave a new way for the designing of high performance bio-carriers, demonstrating their strong potential as a robust platform for diagnosis and therapy. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Thermal dewetting behavior of polystyrene composite thin films with organic-modified inorganic nanoparticles.

PubMed

Kubo, Masaki; Takahashi, Yosuke; Fujii, Takeshi; Liu, Yang; Sugioka, Ken-ichi; Tsukada, Takao; Minami, Kimitaka; Adschiri, Tadafumi

2014-07-29

The thermal dewetting of polystyrene composite thin films with oleic acid-modified CeO2 nanoparticles prepared by the supercritical hydrothermal synthesis method was investigated, varying the nanoparticle concentration (0-30 wt %), film thickness (approximately 50 and 100 nm), and surface energy of silanized silicon substrates on which the composite films were coated. The dewetting behavior of the composite thin films during thermal annealing was observed by an optical microscope. The presence of nanoparticles in the films affected the morphology of dewetting holes, and moreover suppressed the dewetting itself when the concentration was relatively high. It was revealed that there was a critical value of the surface energy of the substrate at which the dewetting occurred. In addition, the spatial distributions of nanoparticles in the composite thin films before thermal annealing were investigated using AFM and TEM. As a result, we found that most of nanoparticles segregated to the surface of the film, and that such distributions of nanoparticles contribute to the stabilization of the films, by calculating the interfacial potential of the films with nanoparticles.

An all-solid-state lithium/polyaniline rechargeable cell

NASA Astrophysics Data System (ADS)

Changzhi, Li; Xinsheng, Peng; Borong, Zhang; Baochen, Wang

The performance of an all-solid-state cell having a lithium negative electrode, a modified polyethylene oxide (PEO)—epoxy resin (ER) electrolyte, and a polyaniline (PAn) positive electrode has been studied using cyclic voltammetry, charge/discharge cycling, and polarization curves at various temperatures. The redox reaction of the PAn electrode at the PAn/modifed PEOER interface exhibits good reversibility. At 50-80 °C, the Li/PEOERLiClO 4/PAn cell shows more than 40 charge/discharge cycles, 90% charge/discharge efficiency, and 54 W h kg -1 discharge energy density (on PAn weight basis) at 50 μA between 2 and 4 V. The polarization performance of the battery improves steadily with increase in temperature.

Brain Localization and Neurotoxicity Evaluation of Polysorbate 80-Modified Chitosan Nanoparticles in Rats

PubMed Central

Yuan, Zhong-Yue; Hu, Yu-Lan; Gao, Jian-Qing

2015-01-01

The toxicity evaluation of inorganic nanoparticles has been reported by an increasing number of studies, but toxicity studies concerned with biodegradable nanoparticles, especially the neurotoxicity evaluation, are still limited. For example, the potential neurotoxicity of Polysorbate 80-modified chitosan nanoparticles (Tween 80-modified chitosan nanoparticles, TmCS-NPs), one of the most widely used brain targeting vehicles, remains unknown. In the present study, TmCS-NPs with a particle size of 240 nm were firstly prepared by ionic cross-linking of chitosan with tripolyphosphate. Then, these TmCS-NPs were demonstrated to be entered into the brain and specially deposited in the frontal cortex and cerebellum after systemic injection. Moreover, the concentration of TmCS-NPs in these two regions was found to decrease over time. Although no obvious changes were observed for oxidative stress in the in vivo rat model, the body weight was found to remarkably decreased in a dose-dependent manner after exposure to TmCS-NPs for seven days. Besides, apoptosis and necrosis of neurons, slight inflammatory response in the frontal cortex, and decrease of GFAP expression in the cerebellum were also detected in mouse injected with TmCS-NPs. This study is the first report on the sub-brain biodistribution and neurotoxicity studies of TmCS-NPs. Our results provide new insights into the toxicity evaluation of nanoparticles and our findings would help contribute to a better understanding of the neurotoxicity of biodegradable nanomaterials used in pharmaceutics. PMID:26248340

Brain Localization and Neurotoxicity Evaluation of Polysorbate 80-Modified Chitosan Nanoparticles in Rats.

PubMed

Yuan, Zhong-Yue; Hu, Yu-Lan; Gao, Jian-Qing

2015-01-01

The toxicity evaluation of inorganic nanoparticles has been reported by an increasing number of studies, but toxicity studies concerned with biodegradable nanoparticles, especially the neurotoxicity evaluation, are still limited. For example, the potential neurotoxicity of Polysorbate 80-modified chitosan nanoparticles (Tween 80-modified chitosan nanoparticles, TmCS-NPs), one of the most widely used brain targeting vehicles, remains unknown. In the present study, TmCS-NPs with a particle size of 240 nm were firstly prepared by ionic cross-linking of chitosan with tripolyphosphate. Then, these TmCS-NPs were demonstrated to be entered into the brain and specially deposited in the frontal cortex and cerebellum after systemic injection. Moreover, the concentration of TmCS-NPs in these two regions was found to decrease over time. Although no obvious changes were observed for oxidative stress in the in vivo rat model, the body weight was found to remarkably decreased in a dose-dependent manner after exposure to TmCS-NPs for seven days. Besides, apoptosis and necrosis of neurons, slight inflammatory response in the frontal cortex, and decrease of GFAP expression in the cerebellum were also detected in mouse injected with TmCS-NPs. This study is the first report on the sub-brain biodistribution and neurotoxicity studies of TmCS-NPs. Our results provide new insights into the toxicity evaluation of nanoparticles and our findings would help contribute to a better understanding of the neurotoxicity of biodegradable nanomaterials used in pharmaceutics.

Detection of telomerase on upconversion nanoparticle modified cellulose paper.

PubMed

Wang, Faming; Li, Wen; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

2015-07-25

Herein we report a convenient and sensitive method for the detection of telomerase activity based on upconversion nanoparticle (UCNP) modified cellulose paper. Compared with many solution-phase systems, this paper chip is more stable and easily stores the test results. What's more, the low background fluorescence of the UCNPs increases the sensitivity of this method, and the low telomerase levels in different cell lines can clearly be discriminated by the naked eye.

Formation of novel hydrogel bio-anode by immobilization of biocatalyst in alginate/polyaniline/titanium-dioxide/graphite composites and its electrical performance.

PubMed

Szöllősi, Attila; Hoschke, Ágoston; Rezessy-Szabó, Judit M; Bujna, Erika; Kun, Szilárd; Nguyen, Quang D

2017-05-01

A new bio-anode containing gel-entrapped bacteria in alginate/polyaniline/TiO 2 /graphite composites was constructed and electrically investigated. Alginate as dopant and template as well as entrapped gel was used for immobilization of microorganism cells. Increase of polyaniline concentration resulted an increase in the conductivity in gels. Addition of 0.01 and 0.02 g/mL polyaniline caused 6-fold and 10-fold higher conductivity, respectively. Furthermore, addition of 0.05 g/mL graphite powder caused 10-fold higher conductivity and 4-fold higher power density, respectively. The combination of polyaniline and graphite resulted 105-fold higher conductivity and 7-fold higher power-density output. Optimized concentrations of polyaniline and graphite powder were determined to be 0.02 g/mL and 0.05 g/mL, respectively. Modified hydrogel anode was successfully used in microbial fuel cell systems both in semi- and continuous operations modes. In semi-continuous mode, about 7.88 W/m 3 power density was obtained after 13 h of fermentation. The glucose consumption rate was calculated to be about 7 mg glucose/h/1.2·10 7  CFU immobilized cells. Similar power density was observed in the continuous operation mode of the microbial fuel cell, and it was operated stably for more than 7 days. Our results are very promising for development of an improved microbial fuel cell with new type of bio-anode that have higher power density and can operate for long term. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication of Au nanoparticles supported on CoFe2O4 nanotubes by polyaniline assisted self-assembly strategy and their magnetically recoverable catalytic properties

NASA Astrophysics Data System (ADS)

Zhang, Zhen; Jiang, Yanzhou; Chi, Maoqiang; Yang, Zezhou; Nie, Guangdi; Lu, Xiaofeng; Wang, Ce

2016-02-01

This article reports the fabrication of magnetically responsive Au nanoparticles supported on CoFe2O4 nanotubes through polyaniline (PANI) assisted self-assembly strategy which can be used as an efficient magnetically recoverable nanocatalyst. The central magnetic CoFe2O4 nanotubes possess a strong magnetic response under an externally magnetic field, enabling an easy and efficient separation from the reaction system for reuse. The thorn-like PANI layer on the surface of CoFe2O4 nanotubes provides large surface area for supporting Au nanocatalysts due to the electrostatic interactions. The as-prepared CoFe2O4/PANI/Au nanotube assemblies exhibit a high catalytic activity for the hydrogenation of 4-nitrophenol by sodium borohydride (NaBH4) at room temperature, with an apparent kinetic rate constant (Kapp) of about 7.8 × 10-3 s-1. Furthermore, the composite nanocatalyst shows a good recoverable property during the catalytic process. This work affords a reliable way in developing multifunctional nanocomposite for catalysis and other potential applications in many fields.

Theoretical and experimental specific capacitance of polyaniline in sulfuric acid

NASA Astrophysics Data System (ADS)

Li, Hanlu; Wang, Jixiao; Chu, Qingxian; Wang, Zhi; Zhang, Fengbao; Wang, Shichang

The theoretical mass specific capacitance (C s) of polyaniline (PANI) is firstly estimated by combining electrical double-layer capacitance and pseudocapacitance. The maximum C s is 2.0 × 10 3 F g -1 for one single PANI electrode. In present work, the PANI nanofiber modified stainless-steel (SS) electrode (PANI/SS) was used to assemble supercapacitors. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicate that the PANI nanofiber has a coarse surface arising from the heterogeneous structure which likes an aggregation of nanoparticles. The performance of the assembled PANI/SS supercapacitors was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge methods in 1.0 M H 2SO 4. The maximum C s obtained from these methods in present work is 608, 445.0, and 524.9 F g -1, respectively, which is only 30%, 22%, and 26% of the theoretical one. The significant difference between the experimental and the theoretical value indicates that only a low percentage of PANI (effective) has contribution to capacitance. The percentage of effective PANI depends on both the diffusion of dopants (counter-anions) and the conductivity of PANI. Under practical conditions, the former factor makes PANI nanofiber behave like a concentric cable with only the shell part involved in the charge/discharge process. The latter one which determines the electron transfer rate in PANI has an influence on the degree of redox reaction. In present work, the heterogeneous structure of the PANI nanofiber has a negative effect on the conductivity.

Preparation of folate-modified pullulan acetate nanoparticles for tumor-targeted drug delivery.

PubMed

Zhang, Hui-zhu; Li, Xue-min; Gao, Fu-ping; Liu, Ling-rong; Zhou, Zhi-min; Zhang, Qi-qing

2010-01-01

The purpose of this work was to develop a novel nano-carrier with targeting property to tumor. In this study, pullulan acetate (PA) was synthesized by the acetylation of pullulan to simplify the preparation technique of nanoparticles. Folic acid (FA) was conjugated to PA in order to improve the cancer-targeting activity. The products were characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Epirubicin-loaded nanoparticles were prepared by a solvent diffusion method. The loading efficiencies and EPI content increased with the amount of triethylamine (TEA) increasing in some degree. FPA nanoparticles could incorporate more epirubicin than PA nanoparticles. The folate-modified PA nanoparticles (FPA/EPI NPs) exhibited faster drug release than PA nanoparticles (PA/EPI NPs) in vitro. Confocal image analysis and flow cytometry test revealed that FPA/EPI NPs exhibited a greater extent of cellular uptake than PA/EPI NPs against KB cells over-expressing folate receptors on the surface. FPA/EPI NPs also showed higher cytotoxicity than PA/EPI NPs. The cytotoxic effect of FPA/EPI NPs to KB cells was inhibited by an excess amount of folic acid, suggesting that the binding and/or uptake were mediated by the folate receptor.

Polyaniline Nanofibers as the Hole Transport Medium in an Inverse Dye-Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Hesselsweet, Ian Brock

In order to become a viable alternative to silicon photovoltaics, dye-sensitized solar cells must overcome several issues primarily resulting from their use of a liquid electrolyte. Much research has gone into correcting these shortcomings by replacing the liquid electrolyte with solid-state hole-transport media. Using these solid-state materials brings new difficulties, such as completely filling the pores in the TiO2 nanostructure, and achieving good adhesion with the dye-coated TiO2. A novel approach to addressing these difficulties is the inverse dye-sensitized solar cell design. In this method the devices are constructed in reverse order, with the solidstate hole-transport medium providing the nanostructure instead of the TiO2. This allows new materials and methods to be used which may better address these issues. In this project, inverse dye-sensitized solar cells using polyaniline nanofibers as the hole transport medium were prepared and characterized. The devices were prepared on fluorine-doped tin oxide (FTO) coated glass electrodes. The first component was a dense spin-coated polyaniline blocking layer, to help prevent short circuiting of the devices. The second layer was a thin film of drop cast polyaniline nanofibers which acted as the hole transport medium and provided high surface area for the dye attachment. The dye used was 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), which was covalently attached to the nanofibers using a Friedel-Crafts acylation. Titania gel was then deposited into the pores of the nanofiber film by controlled hydrolysis of a titanium complex (Tyzor LA). A back electrode of TiO2 nanoparticles sintered on FTO was pressed on top to complete the devices. A typical device generated an open circuit voltage of 0.17 V and a closed circuit current of 5.7 nA/cm2 while the highest open circuit voltage recorded for any variation on a device was 0.31 V and the highest short circuit current was 52 nA/cm2 under AM 1.5 simulated solar

Reinforcement effect of soy protein nanoparticles in amine-modified natural rubber latex

USDA-ARS?s Scientific Manuscript database

Mechanical properties of natural rubber reinforced with soy protein nanoparticles are useful for various rubber applications. However, the properties is further improved by improving interactions between soy protein and rubber. A novel method is used to modify particle surface of natural rubber late...

Optical tracking of organically modified silica nanoparticles as DNA carriers: A nonviral, nanomedicine approach for gene delivery

NASA Astrophysics Data System (ADS)

Roy, Indrajit; Ohulchanskyy, Tymish Y.; Bharali, Dhruba J.; Pudavar, Haridas E.; Mistretta, Ruth A.; Kaur, Navjot; Prasad, Paras N.

2005-01-01

This article reports a multidisciplinary approach to produce fluorescently labeled organically modified silica nanoparticles as a nonviral vector for gene delivery and biophotonics methods to optically monitor intracellular trafficking and gene transfection. Highly monodispersed, stable aqueous suspensions of organically modified silica nanoparticles, encapsulating fluorescent dyes and surface functionalized by cationic-amino groups, are produced by micellar nanochemistry. Gel-electrophoresis studies reveal that the particles efficiently complex with DNA and protect it from enzymatic digestion of DNase 1. The electrostatic binding of DNA onto the surface of the nanoparticles, due to positively charged amino groups, is also shown by intercalating an appropriate dye into the DNA and observing the Förster (fluorescence) resonance energy transfer between the dye (energy donor) intercalated in DNA on the surface of nanoparticles and a second dye (energy acceptor) inside the nanoparticles. Imaging by fluorescence confocal microscopy shows that cells efficiently take up the nanoparticles in vitro in the cytoplasm, and the nanoparticles deliver DNA to the nucleus. The use of plasmid encoding enhanced GFP allowed us to demonstrate the process of gene transfection in cultured cells. Our work shows that the nanomedicine approach, with nanoparticles acting as a drug-delivery platform combining multiple optical and other types of probes, provides a promising direction for targeted therapy with enhanced efficacy as well as for real-time monitoring of drug action. nonviral vector | ORMOSIL nanoparticles | confocal microscopy

Synthesis and immobilization of Ag(0) nanoparticles on diazonium modified electrodes: SECM and cyclic voltammetry studies of the modified interfaces.

PubMed

Noël, Jean-Marc; Zigah, Dodzi; Simonet, Jacques; Hapiot, Philippe

2010-05-18

A versatile method was used to prepare modified surfaces on which metallic silver nanoparticles are immobilized on an organic layer. The preparation method takes advantage, on one hand, of the activated reactivity of some alkyl halides with Ag-Pd alloys to produce metallic silver nanoparticles and, on the other hand, of the facile production of an anchoring polyphenyl acetate layer by the electrografting of substituted diazonium salts on carbon surfaces. Transport properties inside such modified layers were investigated by cyclic voltammetry, scanning electrochemical microscopy (SECM) in feedback mode, and conducting AFM imaging for characterizing the presence and nature of the conducting pathways. The modification of the blocking properties of the surface (or its conductivity) was found to vary to a large extent on the solvents used for surface examination (H(2)O, CH(2)Cl(2), and DMF).

Efficient removal of pathogenic bacteria and viruses by multifunctional amine-modified magnetic nanoparticles.

PubMed

Zhan, Sihui; Yang, Yang; Shen, Zhiqiang; Shan, Junjun; Li, Yi; Yang, Shanshan; Zhu, Dandan

2014-06-15

A novel amine-functionalized magnetic Fe3O4-SiO2-NH2 nanoparticle was prepared by layer-by-layer method and used for rapid removal of both pathogenic bacteria and viruses from water. The nanoparticles were characterized by TEM, EDS, XRD, XPS, FT-IR, BET surface analysis, magnetic property tests and zeta-potential measurements, respectively, which demonstrated its well-defined core-shell structures and strong magnetic responsivity. Pathogenic bacteria and viruses are often needed to be removed conveniently because of a lot of co-existing conditions. The amine-modified nanoparticles we prepared were attractive for capturing a wide range of pathogens including not only bacteriophage f2 and virus (Poliovirus-1), but also various bacteria such as S. aureus, E. coli O157:H7, P. aeruginosa, Salmonella, and B. subtilis. Using as-prepared amine-functionalized MNPs as absorbent, the nonspecific removal efficiency of E. coli O157:H7 or virus was more than 97.39%, while it is only 29.8% with Fe3O4-SiO2 particles. From joint removal test of bacteria and virus, there are over 95.03% harmful E. coli O157:H7 that can be removed from mixed solution with polyclonal anti-E. coli O157:H7 antibody modified nanoparticles. Moreover, the synergy effective mechanism has also been suggested. Copyright © 2014 Elsevier B.V. All rights reserved.

Properties of Ag nanoparticles prepared by modified Tollens' process with the use of different saccharide types

NASA Astrophysics Data System (ADS)

Michalcová, Alena; Machado, Larissa; Marek, Ivo; Martinec, Marek; Sluková, Marcela; Vojtěch, Dalibor

2018-02-01

Silver nanoparticles are well known for their catalytic and antimicrobial properties. In their production, the modified Tollens' process using saccharides as reduction agents is very popular. In this paper, the possibility of silver nanoparticles reduction by fructose, glucose, galactose, mannose, maltose, lactose and saccharose is shown. The size of successfully prepared nanoparticles was 16-70 nm depending on the saccharide type. The influence of NaOH and NH3 presence in reaction mixture on size of nanoparticles was described. Surprisingly good results were obtained using saccharose that is, however, known as non-reducing disaccharide.

Folic acid-modified soy protein nanoparticles for enhanced targeting and inhibitory.

PubMed

Cheng, Xu; Wang, Xin; Cao, Zhipeng; Yao, Weijing; Wang, Jun; Tang, Rupei

2017-02-01

Soy protein isolate (SPI) was hydrolyzed by compound enzymes to give water soluble low molecular soy protein (SP). SP and folic acid (FA) modified SP was polymerized with N-3- acrylamidophenylboronic acid (APBA) monomer in aqueous solution to give SP nanoparticles (SP NPs) and FA modified nanoparticles (FA-SP NPs), respectively. These NPs display excellent stability in different conditions, and have a uniform spherical shape with a diameter around of 200nm. Doxorubicin (DOX) was then successfully loaded into SP and FA-SP NPs with a desirable loading content of 13.33% and 16.01%, respectively. The cellular uptake and cytotoxicity of DOX-loaded SP NPs and FA-SP NPs were investigated using the two-dimensional (2D) monolayer cell model and three-dimensional (3D) multicellular spheroids (MCs). In vivo, tumor accumulation and growth inhibitory were then examined using H22 tumor-bearing mice. All these results demonstrated that conjugation of FA can efficiently enhance SP-based NPs' tumor accumulation and antitumor effect. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermoacoustic molecular tomography with magnetic nanoparticle contrast agents for targeted tumor detection.

PubMed

Nie, Liming; Ou, Zhongmin; Yang, Sihua; Xing, Da

2010-08-01

The primary feasibility steps of demonstrating the ability of microwave-induced thermoacoustic (TA) in phantoms have been previously reported. However, none were shown to target a diseased site in living subjects in thermoacoustic tomography (TAT) field so far. To determine the expressions of oncogenic surface molecules, it is quite necessary to image tumor lesions and acquire pathogenic status on them via TAT. Compared to biological tissues, iron oxide nanoparticles have a much higher microwave absorbance. Fe3O4/polyaniline (PANI) nanoparticles were prepared via polymerization of aniline in the Fe304 superparamagnetic fluids. Then Fe3O4/PANI was conjugated to folic acid (FA), which can bind specifically to the surface of the folate receptor used as a tumor marker. FA-Fe3O4/PANI targeted tumor was irradiated by pulsed microwave at 6 GHz for thermoacoustic detection and imaging. The effect of the Fe3O4/PANI superparamagnetic nanoparticles for enhancing TAT images was successfully investigated in ex vivo human blood and in vivo mouse tail. Intravenous administration of the targeted nanoparticles to mice bearing tumors showed fivefold greater thermoacoustic signal and much longer elimination time than that of mice injected with nontargeted nanoparticles in the tumor. The specific targeting ability of FA-Fe3O4/PANI to tumor was also verified on fluorescence microscopy. Fabricated iron oxide nanoparticles conjugated with tumor ligands for targeted TAT tumor detection at the molecular level was reported for the first time. The results indicate that thermoacoustic molecular imaging with functionalized iron oxide nanoparticles may contribute to targeted and functional early cancer imaging. Also, the modified iron oxide nanoparticles combined with suitable tumor markers may also be used as novel nanomaterials for targeted and guided cancer thermal therapy.

Immobilization of Ag nanoparticles/FGF-2 on a modified titanium implant surface and improved human gingival fibroblasts behavior.

PubMed

Ma, Qianli; Mei, Shenglin; Ji, Kun; Zhang, Yumei; Chu, Paul K

2011-08-01

The objective of this study was to form a rapid and firm soft tissue sealing around dental implants that resists bacterial invasion. We present a novel approach to modify Ti surface by immobilizing Ag nanoparticles/FGF-2 compound bioactive factors onto a titania nanotubular surface. The titanium samples were anodized to form vertically organized TiO(2) nanotube arrays and Ag nanoparticles were electrodeposited onto the nanotubular surface, on which FGF-2 was immobilized with repeated lyophilization. A uniform distribution of Ag nanoparticles/FGF-2 was observed on the TiO(2) nanotubular surface. The L929 cell line was used for cytotoxicity assessment. Human gingival fibroblasts (HGFs) were cultured on the modified surface for cytocompatibility determination. The Ag/FGF-2 immobilized samples displayed excellent cytocompatibility, negligible cytotoxicity, and enhanced HGF functions such as cell attachment, proliferation, and ECM-related gene expression. The Ag nanoparticles also exhibit some bioactivity. In conclusion, this modified TiO(2) nanotubular surface has a large potential for use in dental implant abutment. Copyright © 2011 Wiley Periodicals, Inc.

Effect of linoleic-acid modified carboxymethyl chitosan on bromelain immobilization onto self-assembled nanoparticles

NASA Astrophysics Data System (ADS)

Tan, Yu-long; Liu, Chen-guang; Yu, Le-jun; Chen, Xi-guang

2008-06-01

Hydrogel nanoparticles could be prepared by using linoleic acid (LA) modified carboxymethyl chitosan (CMCS) after sonication. Bromelain could be loaded onto nanoparticles of LA-CMCS. Factors affecting the activity of the immobilized enzyme, including temperature, storage etc., were investigated in this study. The results showed that the stability of bromelain for heat and storage was improved after immobilization on nanoparticles. The Michaelis constant ( K m) of the immobilized enzyme was smaller than that of free enzyme, indicating that the immobilization could promote the stability of the enzyme and strengthen the affinity of the enzyme for the substrate.

A Study of Polymer Interactions with Moisture in Polyaniline and its Derivatives

NASA Astrophysics Data System (ADS)

Dyakonov, A. J.; McCormick, B. J.; Kahol, P. K.

1997-03-01

Electron Spin Resonance experiments have been performed under different sample treatments on powders of polyaniline, poly(ortho)diaminobenzene, poly(ortho)chloroaniline, poly(ortho)toluidine, poly(ortho)ethylaniline, and poly(ortho)propylaniline, with the objective of finding various adsorption sites for water molecules. It is found that water molecules are adsorbed at two distinct sites in polyaniline. Implications of these results will be presented in relation to dc conductivity results and the inhomogeneously disordered metal description of polyaniline.

VAPOR PHASE MERCURY SORPTION BY ORGANIC SULFIDE MODIFIED BIMETALLIC IRON-COPPER NANOPARTICLE AGGREGATES

EPA Science Inventory

Novel organic sulfide modified bimetallic iron-copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120-140 °C). Silane based (disulfide silane and tetrasulfide silane) and alkyl sulfide ...

Nanostructured metal-polyaniline composites

DOEpatents

Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

2010-08-31

Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

Preparation and characterization of APTES modified magnetic MMT capable of using as anisotropic nanoparticles

NASA Astrophysics Data System (ADS)

Li, Yingjun; Chen, Hua; Wu, Jie; He, Qin; Li, Yintao; Yang, Wenbin; Zhou, Yuanlin

2018-07-01

Montmorillonite (MMT) based anisotropic magnetic nanoparticles (Fe3O4/APTES/MMT) with high anisotropy and reliable magnetism were prepared by using Fe3O4 as magnetic nanoparticles and γ-aminopropyltriethoxysilane (ATPES) as modifier. The characterization indicated that the interactions between Fe3O4 nanoparticles and MMT in Fe3O4/APTES/MMT were stronger than that of directly deposited on to MMT (Fe3O4-MMT) because APTES was chemically bonded to both Fe3O4 and MMT. Fe3O4/APTES/MMT had a greater Ms value (25.16 emu/g) than Fe3O4-MMT (23.71 emu/g). Also, ultrasonication was used to test the interactions between Fe3O4 and MMT. With 30 min of ultrasonication, the amount of Fe3O4 nanoparticles on the surface of Fe3O4/APTES/MMT was more than that of Fe3O4-MMT, and Fe3O4/APTES/MMT had a faster magnetic response to a magnetic field than that of Fe3O4-MMT because of enhanced interactions between Fe3O4 and MMT in Fe3O4/APTES/MMT. In addition, Fe3O4 nanoparticles were densely immobilized onto Fe3O4/APTES/MMT with a smaller average diameter, and the distribution of Fe3O4 nanoparticles on the surface of MMT was more uniform than that of Fe3O4-MMT. Fe3O4/APTES/MMT possessed stable and high magnetism, in ease of orientation and recycling in the magnetic field, and this makes it a promising candidate as anisotropic nanoparticles for use in preparing anisotropic inorganic/polymer composites and anisotropic adsorbents used in wastewater treatment. Finally, the mechanism of ATPES-modified magnetic MMT was investigated.

Multidentate zwitterionic chitosan oligosaccharide modified gold nanoparticles: stability, biocompatibility and cell interactions

NASA Astrophysics Data System (ADS)

Liu, Xiangsheng; Huang, Haoyuan; Liu, Gongyan; Zhou, Wenbo; Chen, Yangjun; Jin, Qiao; Ji, Jian

2013-04-01

Surface engineering of nanoparticles plays an essential role in their colloidal stability, biocompatibility and interaction with biosystems. In this study, a novel multidentate zwitterionic biopolymer derivative is obtained from conjugating dithiolane lipoic acid and zwitterionic acryloyloxyethyl phosphorylcholine to the chitosan oligosaccharide backbone. Gold nanoparticles (AuNPs) modified by this polymer exhibit remarkable colloidal stabilities under extreme conditions including high salt conditions, wide pH range and serum or plasma containing media. The AuNPs also show strong resistance to competition from dithiothreitol (as high as 1.5 M). Moreover, the modified AuNPs demonstrate low cytotoxicity investigated by both MTT and LDH assays, and good hemocompatibility evaluated by hemolysis of human red blood cells. In addition, the intracellular fate of AuNPs was investigated by ICP-MS and TEM. It showed that the AuNPs are uptaken by cells in a concentration dependent manner, and they can escape from endosomes/lysosomes to cytosol and tend to accumulate around the nucleus after 24 h incubation but few of them are excreted out of the cells. Gold nanorods are also stabilized by this ligand, which demonstrates robust dispersion stability and excellent hemocompatibility. This kind of multidentate zwitterionic chitosan derivative could be widely used for stabilizing other inorganic nanoparticles, which will greatly improve their performance in a variety of bio-related applications.Surface engineering of nanoparticles plays an essential role in their colloidal stability, biocompatibility and interaction with biosystems. In this study, a novel multidentate zwitterionic biopolymer derivative is obtained from conjugating dithiolane lipoic acid and zwitterionic acryloyloxyethyl phosphorylcholine to the chitosan oligosaccharide backbone. Gold nanoparticles (AuNPs) modified by this polymer exhibit remarkable colloidal stabilities under extreme conditions including high salt

Permeable polyaniline articles for gas separation

DOEpatents

Wang, Hsing-Lin [Los Alamos, NM; Mattes, Benjamin R [Santa Fe, NM

2009-07-21

Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

Permeable polyaniline articles for gas separation

DOEpatents

Wang, Hsing-Lin; Mattes, Benjamin R.

2004-09-28

Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

Design and synthesis of ternary cobalt ferrite/graphene/polyaniline hierarchical nanocomposites for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Xiong, Pan; Huang, Huajie; Wang, Xin

2014-01-01

A ternary cobalt ferrite/graphene/polyaniline nanocomposite (CGP) is designed and fabricated via a facile two-step approach: cobalt ferrite nanoparticles dispersed on graphene sheets are achieved by a hydrothermal method, followed by coating with polyaniline (PANI) through in situ polymerization process. Electrochemical measurements demonstrate that the specific capacitance of the resulting ternary hybrid (CGP) is up to 1133.3 F g-1 at a scan rate of 1 mV s-1 and 767.7 F g-1 at a current density of 0.1 A g-1 using a three-electrode system, while 716.4 F g-1 at a scan rate of 1 mV s-1 and 392.3 F g-1 at a current density of 0.1 A g-1 using a two-electrode system, which are significantly higher than those of pure CoFe2O4, graphene and PANI, or binary CoFe2O4/graphene, CoFe2O4/PANI and graphene/PANI hybrids. In addition, over 96% of the initial capacitance can be retained after repeating test for 5000 cycles, demonstrating a high cycling stability. The extraordinary electrochemical performance of the ternary CGP nanocomposite can be attributed to its well-designed nanostructure and the synergistic effects of the individual components.

Stimuli-responsive polyaniline coated silica microspheres and their electrorheology

NASA Astrophysics Data System (ADS)

Park, Dae Eun; Choi, Hyoung Jin; Vu, Cuong Manh

2016-05-01

Silica/polyaniline (PANI) core-shell structured microspheres were synthesized by coating the surface of silica micro-beads with PANI and applied as a candidate inorganic/polymer composite electrorheological (ER) material. The silica micro-beads were initially modified using N-[(3-trimethoxysilyl)-propyl] aniline to activate an aniline functional group on the silica surface for a better PANI coating. The morphology of the PANI coating on the silica surface was examined by scanning electron microscopy and the silica/PANI core-shell structure was confirmed by transmission electron microscopy. The chemical structure of the particles was confirmed by Fourier transform infrared spectroscopy. Rotational rheometry was performed to confirm the difference in the ER properties between pure silica and silica/PANI microsphere-based ER fluids when dispersed in silicone oil.

Hydrogen gas sensing feature of polyaniline/titania (rutile) nanocomposite at environmental conditions

NASA Astrophysics Data System (ADS)

Milani Moghaddam, Hossain; Nasirian, Shahruz

2014-10-01

The resistance-based sensors of polyaniline/titania (rutile) nanocomposite (TPNC) were prepared by spin coating technique onto an epoxy glass substrate with Cu-interdigited electrodes to study their hydrogen (H2) gas sensing features. Our findings are that the change of the surface morphology, porosity and wt% of titania in TPNCs have a significant effect on H2 gas sensing of sensors. All of the sensors had a reproducibility response toward 0.8 vol% H2 gas at room temperature, air pressure and 50% relative humidity. A sensor with 40 wt% of titania nanoparticles had better response/recovery time and the response than other sensors. Moreover, H2 gas sensing mechanism of TPNC sensors based contact areas and the correlation of energy levels between PANI chains and the titania grains were studied.

Nanobiocomposite platform based on polyaniline-iron oxide-carbon nanotubes for bacterial detection.

PubMed

Singh, Renu; Verma, Rachna; Sumana, G; Srivastava, Avanish Kumar; Sood, Seema; Gupta, Rajinder K; Malhotra, B D

2012-08-01

The nanocomposite based on polyaniline (PANI)-iron oxide nanoparticles (nFe(3)O(4)) and multi walled carbon-nanotubes (CNT) has been fabricated onto indium tin oxide (ITO) coated glass plate via facile electrochemical synthesis of polyaniline in presence of nFe(3)O(4) (~20 nm) and CNT (20-80 nm in diameter). The results of transmission electron microscopic studies show evidence of coating of PANI and nFe(3)O(4) onto the CNT. The PANI-nFe(3)O(4)-CNT/ITO nanoelectrode has been characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy studies. The biotinylated nucleic acid probe sequence consisting of 20 bases has been immobilized onto PANI-nFe(3)O(4)-CNT/ITO nanoelectrode using biotin-avidin coupling. It is shown that the PANI-nFe(3)O(4)-CNT platform based biosensor can be used to specifically detect bacteria (N. gonorrhoeae) at minute concentration as low as (1×10(-19) M) indicating high sensitivity within 45 s of hybridization time at 298 K by differential pulse voltammetry using methylene blue as electroactive indicator. This bacterial sensor has also been tested with 4 positive and 4 negative PCR amplicons of gonorrhoea affected patient samples. The results of these studies have implications towards the fabrication of a handheld device for Neisseria gonorrhoeae detection that may perhaps result in a decrease in the human immunodeficiency virus infections. Copyright © 2012 Elsevier B.V. All rights reserved.

Self-doped polyaniline multifunctional optical probes in confined nanostructure for pH sensing

NASA Astrophysics Data System (ADS)

Hong, Yoochan; Hwang, Seungyeon; Yang, Jaemoon

2017-07-01

We have successfully fabricated nanocomposite, which is composed of polyaniline (PAni) and pyrene butyric acid (Pyba) via solvent shift method, and the outer layer was enclosed by Tween 80 as a surfactant. First of all, the various ratios between PAni and Pyba were applied for synthesis of polyaniline nanocomposite, and an identical condition for exhibition of proper absorbance and fluorescence properties was found out. The morphology of polyaniline nanocomposite was confirmed via scanning electron microscopic imaging and hydrodynamic size was also confirmed by dynamic light scattering method. We demonstrated that confined self-doped polyaniline nanocomposite as a pH sensing agent are preserved in the doped state even at a neutral pH value. Especially, PAni exhibited strong convertible property at absorbance spectra, on the other hand, Pyba showed changing property at fluorescence spectra at various pH values. In conclude, this polyaniline nanocomposite can accomplish as a fine nanoagent expressing absorbance and fluorescence properties according to surrounding pH values.

Ternary manganese ferrite/graphene/polyaniline nanostructure with enhanced electrochemical capacitance performance

NASA Astrophysics Data System (ADS)

Xiong, Pan; Hu, Chenyao; Fan, Ye; Zhang, Wenyao; Zhu, Junwu; Wang, Xin

2014-11-01

A ternary manganese ferrite/graphene/polyaniline (MGP) nanostructure is designed and synthesized via a facile two-step approach. This nanostructure exhibits outstanding electrochemical performances, such as high specific capacitance (454.8 F g-1 at 0.2 A g-1), excellent rate capability (75.8% capacity retention at 5 A g-1), and good cycling stability (76.4% capacity retention after 5000 cycles at 2 A g-1), which are superior to those of its individual components (manganese ferrite, reduced-graphene oxide, polyaniline) and corresponding binary hybrids (manganese ferrite/graphene (MG), manganese ferrite/polyaniline (MP), and graphene/polyaniline (GP)). A symmetric supercapacitor device using the as-obtained hybrid has been fabricated and tested. The device exhibits a high specific capacitance of 307.2 F g-1 at 0.1 A g-1 with a maximum energy density of 13.5 W h kg-1. The high electrochemical performance of ternary MGP can be attributed to its well-designed nanostructure and the synergistic effect of the individual components.

In Vivo Neural Recording and Electrochemical Performance of Microelectrode Arrays Modified by Rough-Surfaced AuPt Alloy Nanoparticles with Nanoporosity

PubMed Central

Zhao, Zongya; Gong, Ruxue; Zheng, Liang; Wang, Jue

2016-01-01

In order to reduce the impedance and improve in vivo neural recording performance of our developed Michigan type silicon electrodes, rough-surfaced AuPt alloy nanoparticles with nanoporosity were deposited on gold microelectrode sites through electro-co-deposition of Au-Pt-Cu alloy nanoparticles, followed by chemical dealloying Cu. The AuPt alloy nanoparticles modified gold microelectrode sites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and in vivo neural recording experiment. The SEM images showed that the prepared AuPt alloy nanoparticles exhibited cauliflower-like shapes and possessed very rough surfaces with many different sizes of pores. Average impedance of rough-surfaced AuPt alloy nanoparticles modified sites was 0.23 MΩ at 1 kHz, which was only 4.7% of that of bare gold microelectrode sites (4.9 MΩ), and corresponding in vitro background noise in the range of 1 Hz to 7500 Hz decreased to 7.5 μVrms from 34.1 μVrms at bare gold microelectrode sites. Spontaneous spike signal recording was used to evaluate in vivo neural recording performance of modified microelectrode sites, and results showed that rough-surfaced AuPt alloy nanoparticles modified microelectrode sites exhibited higher average spike signal-to-noise ratio (SNR) of 4.8 in lateral globus pallidus (GPe) due to lower background noise compared to control microelectrodes. Electro-co-deposition of Au-Pt-Cu alloy nanoparticles combined with chemical dealloying Cu was a convenient way for increasing the effective surface area of microelectrode sites, which could reduce electrode impedance and improve the quality of in vivo spike signal recording. PMID:27827893

Physicochemical properties and in vitro cytotoxicity of iron oxide-based nanoparticles modified with antiangiogenic and antitumor peptide A7R

NASA Astrophysics Data System (ADS)

Niescioruk, Anna; Nieciecka, Dorota; Puszko, Anna K.; Królikowska, Agata; Kosson, Piotr; Perret, Gerard Y.; Krysinski, Pawel; Misicka, Aleksandra

2017-05-01

Superparamagnetic iron oxide-based nanoparticles (SPIONs) are promising carriers as targeted drug delivery vehicles, because they can be guided to their target with the help of an external magnetic field. Functionalization of nanoparticles' surface with molecules, which bind with high affinity to receptors on target tissue significantly facilitates delivery of coated nanoparticles to their targeted site. Here, we demonstrate conjugation of an antiangiogenic and antitumor peptide ATWLPPR (A7R) to SPIONs modified with sebacic acid (SPIONs-SA). Successful conjugation was confirmed by various analytical techniques (FTIR, SERS, SEM-EDS, TEM, TGA). Cell cytotoxicity studies, against two cell lines (HUVEC and MDA-MB-231) indicated that SPIONs modified with A7R reduced HUVEC cell viability at concentrations higher than 0.01 mg Fe/mL, in comparison to cells that were exposed to either the nanoparticles modified with sebacic acid or A7R peptide solely, what might be partially caused by a process of internalization.

Optimization and characterization of high pressure homogenization produced chemically modified starch nanoparticles.

PubMed

Ding, Yongbo; Kan, Jianquan

2017-12-01

Chemically modified starch (RS4) nanoparticles were synthesized through homogenization and water-in-oil mini-emulsion cross-linking. Homogenization was optimized with regard to z-average diameter by using a three-factor-three-level Box-Behnken design. Homogenization pressure (X 1 ), oil/water ratio (X 2 ), and surfactant (X 3 ) were selected as independent variables, whereas z-average diameter was considered as a dependent variable. The following optimum preparation conditions were obtained to achieve the minimum average size of these nanoparticles: 50 MPa homogenization pressure, 10:1 oil/water ratio, and 2 g surfactant amount, when the predicted z-average diameter was 303.6 nm. The physicochemical properties of these nanoparticles were also determined. Dynamic light scattering experiments revealed that RS4 nanoparticles measuring a PdI of 0.380 and an average size of approximately 300 nm, which was very close to the predicted z-average diameter (303.6 nm). The absolute value of zeta potential of RS4 nanoparticles (39.7 mV) was higher than RS4 (32.4 mV), with strengthened swelling power. X-ray diffraction results revealed that homogenization induced a disruption in crystalline structure of RS4 nanoparticles led to amorphous or low-crystallinity. Results of stability analysis showed that RS4 nanosuspensions (particle size) had good stability at 30 °C over 24 h.

Use of hydroxypropyl-β-cyclodextrin/polyethylene glycol 400, modified Fe3O4 nanoparticles for congo red removal.

PubMed

Yu, Lan; Xue, Weihua; Cui, Lei; Xing, Wen; Cao, Xinli; Li, Hongyu

2014-03-01

Fe3O4 nanoparticles were modified with Hydroxypropyl-β-cyclodextrin (HP-β-CD) and Polyethylene glycol 400 (PEG400) by a facile one-pot homogeneous precipitation method, and were used as a novel nano-adsorbent for the removal of congo red (CR) from aqueous solutions. The polymer-modified composites were characterized by FTIR, TEM, TGA, XRD and VSM, and showed excellent adsorption efficiency for CR. The value of the maximum adsorption capacity calculated according to the Langmuir isotherm model were 1.895g/g, which are much high and about 19 times that of Fe3O4 nanoparticles. Desorption study further indicates the good regeneration ability of the nanocomposites. The results suggest that the HP-β-CD/PEG400-modified Fe3O4 nanoparticles is a promising adsorbent for CR removal from aqueous solutions, and it is easily recycled owing to its large specific surface area and unique magnetic responsiveness. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Conductive cotton prepared by polyaniline in situ polymerization using laccase.

PubMed

Zhang, Ya; Dong, Aixue; Wang, Qiang; Fan, Xuerong; Cavaco-Paulo, Artur; Zhang, Ying

2014-09-01

The high-redox-potential catalyst laccase, isolated from Aspergillus, was first used as a biocatalyst in the oxidative polymerization of water-soluble conductive polyaniline, and then conductive cotton was prepared by in situ polymerization under the same conditions. The polymerization of aniline was performed in a water dispersion of sodium dodecylbenzenesulfonate (SDBS) micellar solution with atmospheric oxygen serving as the oxidizing agent. This method is ecologically clean and permits a greater degree of control over the kinetics of the reaction. The conditions for polyaniline synthesis were optimized. Characterizations of the conducting polyaniline and cotton were carried out using Fourier transform infrared spectroscopy, UV-vis spectroscopy, cyclic voltammetry, the fabric induction electrostatic tester, and the far-field EMC shielding effectiveness test fixture.

Organically Modified Silica Nanoparticles Are Biocompatible and Can Be Targeted to Neurons In Vivo

PubMed Central

Kumar, Rajiv; Iacobucci, Gary J.; Kuznicki, Michelle L.; Kosterman, Andrew; Bergey, Earl J.; Prasad, Paras N.; Gunawardena, Shermali

2012-01-01

The application of nanotechnology in biological research is beginning to have a major impact leading to the development of new types of tools for human health. One focus of nanobiotechnology is the development of nanoparticle-based formulations for use in drug or gene delivery systems. However most of the nano probes currently in use have varying levels of toxicity in cells or whole organisms and therefore are not suitable for in vivo application or long-term use. Here we test the potential of a novel silica based nanoparticle (organically modified silica, ORMOSIL) in living neurons within a whole organism. We show that feeding ORMOSIL nanoparticles to Drosophila has no effect on viability. ORMOSIL nanoparticles penetrate into living brains, neuronal cell bodies and axonal projections. In the neuronal cell body, nanoparticles are present in the cytoplasm, but not in the nucleus. Strikingly, incorporation of ORMOSIL nanoparticles into the brain did not induce aberrant neuronal death or interfered with normal neuronal processes. Our results in Drosophila indicate that these novel silica based nanoparticles are biocompatible and not toxic to whole organisms, and has potential for the development of long-term applications. PMID:22238611

Physicochemical properties of silica gel coated with a thin layer of polyaniline (PANI) and its application in non-suppressed ion chromatography.

PubMed

Sowa, Ireneusz; Kocjan, Ryszard; Wójciak-Kosior, Magdalena; Swieboda, Ryszard; Zajdel, Dominika; Hajnos, Mieczysław

2013-10-15

Physicochemical properties of a new sorbent and its potential application in non-suppressed ion chromatography (IC) have been investigated. The sorbent was obtained in a process of covering silica gel particles with a film of polyaniline (PANI). The properties of silica modified with polyaniline such as particle size, porosity, average quantity of polyaniline covering carrier and density of sorbent were determined. In our study the following methods were used: microscopic analysis, laser diffraction technique, combustion analysis, mercury porosimetry and helium pycnometry. Column with the newly obtained packing was used for the separation of inorganic anions. Optimized chromatographic system was successfully employed for analysis of iodide and bromide in selected pharmaceutical products (Bochnia salt and Iwonicz salt) applied in chronic respiratory disease. Analysis was carried out using 0.1M solution of HCl in mixture of methanol/water (50:50v/v) as a mobile phase; the flow rate was 0.3 mL min(-1), temperature was 24°C and λ=210 nm. Validation parameters such as correlation coefficient, RSD values, recovery, detection and quantification limits were found to be satisfactory. Copyright © 2013 Elsevier B.V. All rights reserved.

Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

NASA Astrophysics Data System (ADS)

Deb, K.; Bhowmik, K. L.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

2016-05-01

Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors.

PubMed

Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

2017-02-16

Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 μM and 8.0 μA/μM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications.

Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors

PubMed Central

Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

2017-01-01

Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 µM and 8.0 µA/µM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications. PMID:28336878

Use of facile mechanochemical method to functionalize carbon nanofibers with nanostructured polyaniline and their electrochemical capacitance

PubMed Central

2012-01-01

A facile approach to functionalize carbon nanofibers [CNFs] with nanostructured polyaniline was developed via in situ mechanochemical polymerization of polyaniline in the presence of chemically treated CNFs. The nanostructured polyaniline grafting on the CNF was mainly in a form of branched nanofibers as well as rough nanolayers. The good dispersibility and processability of the hybrid nanocomposite could be attributed to its overall nanostructure which enhanced its accessibility to the electrolyte. The mechanochemical oxidation polymerization was believed to be related to the strong Lewis acid characteristic of FeCl3 and the Lewis base characteristic of aniline. The growth mechanism of the hierarchical structured nanofibers was also discussed. After functionalization with the nanostructured polyaniline, the hybrid polyaniline/CNF composite showed an enhanced specific capacitance, which might be related to its hierarchical nanostructure and the interaction between the aromatic polyaniline molecules and the CNFs. PMID:22315992

Development of a nanoparticle-based surface-modified fluorescence assay for the detection of prion proteins.

PubMed

Henry, James; Anand, Ashish; Chowdhury, Mustafa; Coté, Gerard; Moreira, Rosana; Good, Theresa

2004-11-01

A nanoparticle-based immunoassay for the detection of recombinant bovine prion protein (PrP) was developed as a step in the development of screening tools for the prevention of the spread of transmissible spongiform encephalopathies. The assay is based on the competitive binding between PrP and a peptide-fluorophore to a nanoparticle-labeled antibody which is specific for a conserved prion sequence. The fluorophore, when bound to the antibody, is subject to surfaced-modified fluorescence, enabling detection of changes in the concentration of bound fluorophore in the presence of prion protein. Important factors considered during the development of the assay were ease of use, robustness, and detection level. The effects of pH and nanoparticle conjugation chemistry on surface-modified fluorescence observed in the assay were explored. Effects of concentrations of antibody and fluorophore on reproducibility and detection limits were examined. At present, the detection limits of the system are approximately equal to the antibody-peptide fluorophore equilibrium dissociation constant, which is near one nanomolar concentration. Improved assay performance could be obtained by optimization of the nanoparticle surface resonance effects. The simplicity of the assay and ease of use may make the type of assay described in this report attractive for screening purposes in the food industry.

Factors influencing preparation of polyaniline doped with hydrochloric acid

NASA Astrophysics Data System (ADS)

Chuanyu, Sun; Yu, Wang

2014-12-01

Factors influencing the reaction of chemical polymerization during aniline doping with hydrochloric acid (HCl) have been studied in this work. The optimal parameters for the preparation of polyaniline were determined as follows: aniline concentration - 4 mass %, molar ratios of oxidant (NH4)2S2O8:aniline - 1.2:1 and 1.3:1, the concentration of dopant - 1 mol/L. Fourier transform infrared spectroscopy (FT-IR) was applied to characterize the structure of polyaniline.

Polyaniline/MWCNTs/starch modified carbon paste electrode for non-enzymatic detection of cholesterol: application to real sample (cow milk).

PubMed

Gautam, Vineeta; Singh, Karan P; Yadav, Vijay L

2018-03-01

Nanocomposite materials are potentially revolutionizing many technologies, including sensors. In this paper, we described the application of "PANI/MWCNTs/Starch" modified carbon paste electrode (PCS-CPE) as a simple and highly sensitive cholesterol sensor. This novel nano-composite material has integrated nano-morphology, where polyaniline could interact effectively with the additives; pi-pi stacking "MWCNTs," and covalently bonded with starch. Specific binding sites (sugar chains), better electro-catalytic properties and fast electron transfer facilitated the oxidation of cholesterol. Fourier transform infrared spectra confirmed the interaction of cholesterol with the composite material. The sensing response of PCS was measured by cyclic voltammetry and chronoamperometry (0.1 M PBS-5 used as supporting electrolyte). As the amount of cholesterol increased in the test solution, cyclic voltammograms showed a rise of peak current (cathodic and anodic). Under the normal experimental conditions, the developed sensor exhibited wide linear dynamic range (0.032 to 5 mM) (upper limit is due to lack of solubility of cholesterol), high sensitivity (800 μAmM -1  cm -2 ), low detection limit (0.01 mM) and shorter response time (within 4-6 s). Analytical specificity, selectivity, and sensitivity during cholesterol estimation were compared with the response of some other analytes (ascorbic acid, glucose, l-dopa, urea and lactic acid). This novel sensor was successfully applied to estimate cholesterol in cow milk (used as a model real sample). The sensing platform is highly sensitive and shows a linear response towards cholesterol without using any additional redox mediator or enzyme, thus this material is extremely promising for the realization of a low-cost integrated cholesterol sensor device. Graphical abstract Cyclic voltammetric response of cholesterol of composite modified carbon paste capillary electrode.

Polyaniline/Fe3O4-RGO Nanocomposites for Microwave Absorption

NASA Astrophysics Data System (ADS)

Mathew, Jithin; Sathishkumar, M.; Kothurkar, Nikhil K.; Senthilkumar, R.; Sabarish Narayanan, B.

2018-02-01

Fe3O4 nanoparticles were synthesized by co-precipitation of ferric chloride (FeCl3) and ferrous chloride (FeCl2). Reduced graphene oxide (RGO) was prepared by reducing the graphene oxide, which was synthesized by Hummer’s method, using hydrazine hydrate. Three nanocomposites based on sodium dodecyl benzene sulphonate (SDBS)-doped polyaniline were synthesized through in situ polymerization in the presence of the fillers (i) Fe3O4, (ii) reduced graphene oxide (RGO) and (iii) Fe3O4-decorated RGO respectively. The synthesized PANI and the composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Their microstructures, electrical conductivities, and EMI shielding effectiveness were studied. The nanocomposite containing 10 % RGO showed the maximum electrical conductivity and the one with 10 % RGO and 10 % Fe3O4 showed the maximum EMI shielding effectiveness of 7.5 dB for a 1 mm thick sample.

Surface analysis of gold nanoparticles functionalized with thiol-modified glucose SAMs for biosensor applications.

NASA Astrophysics Data System (ADS)

Spampinato, Valentina; Parracino, Mariaantonietta; La Spina, Rita; Rossi, Francois; Ceccone, Giacomo

2016-02-01

In this work, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Principal Component Analysis (PCA) and X-ray Photoelectron Spectroscopy (XPS) have been used to characterize the surface chemistry of gold substrates before and after functionalization with thiol-modified glucose self-assembled monolayers and subsequent biochemical specific recognition of maltose binding protein (MBP). The results indicate that the surface functionalization is achieved both on flat and nanoparticles gold substrates thus showing the potential of the developed system as biodetection platform. Moreover, the method presented here has been found to be a sound and valid approach to characterize the surface chemistry of nanoparticles functionalized with large molecules. Both techniques were proved to be very useful tools for monitoring all the functionalization steps, including the investigation of the biological behaviour of the glucose-modified particles in presence of the maltose binding protein.

An Optical Biosensing Platform using Reprecipitated Polyaniline Microparticles

NASA Astrophysics Data System (ADS)

Nemzer, Louis; Epstein, Arthur

2009-03-01

A great deal of effort remains focused on the goal of developing a continuous in vivo glucose monitoring system for patients with diabetes mellitus. We report a proof-of-concept study on a reagentless optical biosensing platform that circumvents the problems usually associated with direct glucose detection by utilizing the UV-VIS absorption properties of polyaniline, a biocompatible polymer. When the enzyme glucose oxidase is entrapped within reprecipitated polyaniline microparticles, a glucose molecule readily donates two protons and two electrons to the polyaniline, reversibly altering the polymer's oxidation state. The resultant change can be monitored by measuring the absorption at wavelengths that fall within the ``optical window'' for skin. The micro-structured morphology also insures a high surface-area to volume ratio. Data from in vitro prototype devices indicate that in the low enzyme-loading regime, the response can be fit to the Michaelis-Menten model for enzyme kinetics, but at higher enzyme loading, diffusion effects dominate. As a biosensing platform, the system also has the potential to be adapted to detect other biologically relevant analytes, including cholesterol and ethanol.

Electrocatalytic oxidation and determination of insulin at nickel oxide nanoparticles-multiwalled carbon nanotube modified screen printed electrode.

PubMed

Rafiee, Banafsheh; Fakhari, Ali Reza

2013-08-15

Nickel oxide nanoparticles modified nafion-multiwalled carbon nanotubes screen printed electrode (NiONPs/Nafion-MWCNTs/SPE) were prepared using pulsed electrodeposition of NiONPs on the MWCNTs/SPE surface. The size, distribution and structure of the NiONPs/Nafion-MWCNTs were characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD) and also the results show that NiO nanoparticles were homogeneously electrodeposited on the surfaces of MWCNTs. Also, the electrochemical behavior of NiONPs/Nafion-MWCNTs composites in aqueous alkaline solutions of insulin was studied by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS). It was found that the prepared nanoparticles have excellent electrocatalytic activity towards insulin oxidation due to special properties of NiO nanoparticles. Cyclic voltammetric studies showed that the NiONPs/Nafion-MWCNTs film modified SPE, lowers the overpotentials and improves electrochemical behavior of insulin oxidation, as compared to the bare SPE. Amperometry was also used to evaluate the analytical performance of modified electrode in the quantitation of insulin. Excellent analytical features, including high sensitivity (1.83 μA/μM), low detection limit (6.1 nM) and satisfactory dynamic range (20.0-260.0 nM), were achieved under optimized conditions. Moreover, these sensors show good repeatability and a high stability after a while or successive potential cycling. Copyright © 2013 Elsevier B.V. All rights reserved.

Immobilization of xanthine oxidase on a polyaniline silicone support.

PubMed

Nadruz, W; Marques, E T; Azevedo, W M; Lima-Filho, J L; Carvalho, L B

1996-03-01

A polyaniline silicone support to immobilize xanthine oxidase is proposed as a reactor coil to monitor the action of xanthine oxidase on hypoxanthine, xanthine and 6-mercaptopurine. A purified xanthine oxidase immobilized on this support lost 80% of the initial activity after 12 min of use. Co-immobilization of superoxide dismutase and catalase increased the stability of immobilized xanthine oxidase so that the derivative maintained 79% of its initial activity after 4.6 h of continuous use in which 1.5 mumol purine bases were converted by the immobilized enzyme system. There is no evidence of either polyaniline or protein leaching from the coil during 3 h of continuous use. When solutions (10 ml) of hypoxanthine, xanthine and 6-mercaptopurine were circulated individually through the xanthine oxidase-superoxide dismutase-catalase-polyaniline coil (1 mm internal diameter and 3 m in length, 3 ml internal volume) activities of 8.12, 11.17 and 1.09 nmol min-1 coil-1, respectively, were obtained. The advantages of the reactor configuration and the redox properties of the polymer, particularly with respect to immobilized oxidoreductases, make this methodology attractive for similar enzyme systems. This immobilized enzyme system using polyaniline-silicone as support converted 6-mercaptopurine to 6-thiouric acid with equal efficiency as resins based on polyacrylamide and polyamide 11.

Curcumin modified silver nanoparticles for highly efficient inhibition of respiratory syncytial virus infection

NASA Astrophysics Data System (ADS)

Yang, Xiao Xi; Li, Chun Mei; Huang, Cheng Zhi

2016-01-01

Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition effect against respiratory syncytial virus (RSV) infection, giving a decrease of viral titers about two orders of magnitude at the concentration of cAgNPs under which no toxicity was found to the host cells. Mechanism investigations showed that cAgNPs could prevent RSV from infecting the host cells by inactivating the virus directly, indicating that cAgNPs are a novel promising efficient virucide for RSV.Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition

Modified denatured lysozyme effectively solubilizes fullerene c60 nanoparticles in water

NASA Astrophysics Data System (ADS)

Siepi, Marialuisa; Politi, Jane; Dardano, Principia; Amoresano, Angela; De Stefano, Luca; Monti, Daria Maria; Notomista, Eugenio

2017-08-01

Fullerenes, allotropic forms of carbon, have very interesting pharmacological effects and engineering applications. However, a very low solubility both in organic solvents and water hinders their use. Fullerene C60, the most studied among fullerenes, can be dissolved in water only in the form of nanoparticles of variable dimensions and limited stability. Here the effect on the production of C60 nanoparticles by a native and denatured hen egg white lysozyme, a highly basic protein, has been systematically studied. In order to obtain a denatured, yet soluble, lysozyme derivative, the four disulfides of the native protein were reduced and exposed cysteines were alkylated by 3-bromopropylamine, thus introducing eight additional positive charges. The C60 solubilizing properties of the modified denatured lysozyme proved to be superior to those of the native protein, allowing the preparation of biocompatible highly homogeneous and stable C60 nanoparticles using lower amounts of protein, as demonstrated by dynamic light scattering, transmission electron microscopy and atomic force microscopy studies. This lysozyme derivative could represent an effective tool for the solubilization of other carbon allotropes.

Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deb, K.; Bera, A.; Saha, B., E-mail: biswajit.physics@gmail.com

2016-05-23

Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline filmmore » is well suited for their applications in electronic devices.« less

Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes

PubMed Central

Kim, Kyoung-Min; Choi, Mun-Hyoung; Lee, Jong-Kwon; Jeong, Jayoung; Kim, Yu-Ri; Kim, Meyoung-Kon; Paek, Seung-Min; Oh, Jae-Min

2014-01-01

In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development. All four samples had a well crystallized Wurtzite phase, with particle sizes of ∼30 nm and ∼70 nm after coating with organic molecules. The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding. Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about −40 mV) or positive (about +25 mV). Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties. PMID:25565825

Preparation of glucose sensors using gold nanoparticles modified diamond electrode

NASA Astrophysics Data System (ADS)

Fachrurrazie; Ivandini, T. A.; Wibowo, W.

2017-04-01

A glucose sensor was successfully developed by immobilizing glucose oxidase (GOx) at boron-doped diamond (BDD) electrodes. Prior to GOx immobilization, the BDD was modified with gold nanoparticles (AuNPs). To immobilize AuNPs, the gold surface was modified to nitrogen termination. The characterization of the electrode surface was performed using an X-ray photoelectron spectroscopy and a scanning electron microscope, while the electrochemical properties of the enzyme electrode were characterized using cyclic voltammetry. Cyclic voltammograms of the prepared electrode for D-glucose in phosphate buffer solution pH 7 showed a new reduction peak at +0.16 V. The currents of the peak were linear in the concentration range of 0.1 M to 0.9 M, indicated that the GOx-AuNP-BDD can be applied for electrochemical glucose detection.

Synthesis and characterization of hollow magnetic nanospheres modified with Au nanoparticles for bio-encapsulation

NASA Astrophysics Data System (ADS)

Seisno, Satoshi; Suga, Kent; Nakagawa, Takashi; Yamamoto, Takao A.

2017-04-01

Hollow magnetic nanospheres modified with Au nanoparticles were successfully synthesized. Au/SiO2 nanospheres fabricated by a radiochemical process were used as templates for ferrite templating. After the ferrite plating process, Au/SiO2 templates were fully coated with magnetite nanoparticles. Dissolution of the SiO2 core lead to the formation of hollow magnetic nanospheres with Au nanoparticles inside. The hollow magnetic nanospheres consisted of Fe3O4 grains, with an average diameter of 60 nm, connected to form the sphere wall, inside which Au grains with an average diameter of 7.2 nm were encapsulated. The Au nanoparticles immobilized on the SiO2 templates contributed to the adsorption of the Fe ion precursor and/or Fe3O4 seeds. These hollow magnetic nanospheres are proposed as a new type of nanocarrier, as the Au grains could specifically immobilize biomolecules inside the hollow sphere.

Silymarin-Loaded Nanoparticles Based on Stearic Acid-Modified Bletilla striata Polysaccharide for Hepatic Targeting.

PubMed

Ma, Yanni; He, Shaolong; Ma, Xueqin; Hong, Tongtong; Li, Zhifang; Park, Kinam; Wang, Wenping

2016-02-29

Silymarin has been widely used as a hepatoprotective drug in the treatment of various liver diseases, yet its effectiveness is affected by its poor water solubility and low bioavailability after oral administration, and there is a need for the development of intravenous products, especially for liver-targeting purposes. In this study, silymarin was encapsulated in self-assembled nanoparticles of Bletilla striata polysaccharide (BSP) conjugates modified with stearic acid and the physicochemical properties of the obtained nanoparticles were characterized. The silymarin-loaded micelles appeared as spherical particles with a mean diameter of 200 nm under TEM. The encapsulation of drug molecules was confirmed by DSC thermograms and XRD diffractograms, respectively. The nanoparticles exhibited a sustained-release profile for nearly 1 week with no obvious initial burst. Compared to drug solutions, the drug-loaded nanoparticles showed a lower viability and higher uptake intensity on HepG2 cell lines. After intravenous administration of nanoparticle formulation for 30 min to mice, the liver became the most significant organ enriched with the fluorescent probe. These results suggest that BSP derivative nanoparticles possess hepatic targeting capability and are promising nanocarriers for delivering silymarin to the liver.

Highly sensitive and rapid detection of acetylcholine using an ITO plate modified with platinum-graphene nanoparticles.

PubMed

Chauhan, Nidhi; Narang, Jagriti; Jain, Utkarsh

2015-03-21

Determining the concentrations of acetylcholine (ACh) and choline (Ch) is clinically important. ACh is a neurotransmitter that acts as a key link in the communication between neurons in the spinal cord and in nerve skeletal junctions in vertebrates, and plays an important role in transmitting signals in the brain. A bienzymatic sensor for the detection of ACh was prepared by co-immobilizing choline oxidase (ChO) and acetylcholinesterase (AChE) on graphene matrix/platinum nanoparticles, and then electrodepositing them on an ITO-coated glass plate. Graphene nanoparticles were decorated with platinum nanoparticles and were electrodeposited on a modified ITO-coated glass plate to form a modified electrode. The modified electrode was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies. The optimum response of the enzyme electrode was obtained at pH 7.0 and 35 °C. The response time of this ACh-sensing system was shown to be 4 s. The linear range of responses to ACh was 0.005-700 μM. This biosensor exhibits excellent anti-interferential abilities and good stability, retaining 50% of its original current even after 4 months. It has been applied for the detection of ACh levels in human serum samples.

Novel function of polyaniline for biological environments: Cultivation of paramecium in the presence of polyaniline

NASA Astrophysics Data System (ADS)

Goto, Hiromasa

2014-03-01

The reduced form of polyaniline (PANI, emeraldine base) functions as water purification to extend the lives of paramecia. The emeraldine base can absorb discharged waste from the planktons such as nitrogenous compounds and salts. This is a new function of π-conjugated polymers for micro-organisms.

Preparation of nanosize polyaniline and its utilization for microwave absorber.

PubMed

Abbas, S M; Dixit, A K; Chatterjee, R; Goel, T C

2007-06-01

Polyaniline powder in nanosize has been synthesized by chemical oxidative route. XRD, FTIR, and TEM were used to characterize the polyaniline powder. Crytallite size was estimated from XRD profile and also ascertained by TEM in the range of 15 to 20 nm. The composite absorbers have been prepared by mixing different ratios of polyaniline into procured polyurethane (PU) binder. The complex permittivity (epsilon' - jepsilon") and complex permeability (mu' - jmu") were measured in X-band (8.2-12.4 GHz) using Agilent network analyzer (model PNA E8364B) and its software module 85071 (version 'E'). Measured values of these parameters were used to determine the reflection loss at different frequencies and sample thicknesses, based on a model of a single layered plane wave absorber backed by a perfect conductor. An optimized polyaniline/PU ratio of 3:1 has given a minimum reflection loss of -30 dB (99.9% power absorption) at the central frequency 10 GHz and the bandwidth (full width at half minimum) of 4.2 GHz over whole X-band (8.2 to 12.4 GHz) in a sample thickness of 3.0 mm. The prepared composites can be fruitfully utilized for suppression of electromagnetic interference (EMI) and reduction of radar signatures (stealth technology).

Surface Analysis of Gold Nanoparticles Functionalized with Thiol-Modified Glucose SAMs for Biosensor Applications

PubMed Central

Spampinato, Valentina; Parracino, Maria Antonietta; La Spina, Rita; Rossi, Francois; Ceccone, Giacomo

2016-01-01

In this work, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Principal Component Analysis (PCA) and X-ray Photoelectron Spectroscopy (XPS) have been used to characterize the surface chemistry of gold substrates before and after functionalization with thiol-modified glucose self-assembled monolayers and subsequent biochemical specific recognition of maltose binding protein (MBP). The results indicate that the surface functionalization is achieved both on flat and nanoparticles gold substrates thus showing the potential of the developed system as biodetection platform. Moreover, the method presented here has been found to be a sound and valid approach to characterize the surface chemistry of nanoparticles functionalized with large molecules. Both techniques were proved to be very useful tools for monitoring all the functionalization steps, including the investigation of the biological behavior of the glucose-modified particles in the presence of the maltose binding protein. PMID:26973830

Surface morphology and electrochemical studies on polyaniline/CuO nano composites

NASA Astrophysics Data System (ADS)

Ashokkumar, S. P.; Vijeth, H.; Yesappa, L.; Niranjana, M.; Vandana, M.; Basappa, M.; Devendrappa, H.

2018-05-01

An electrochemically synthesized Polyaniline (PANI) and Polyaniline/copper oxide (PCN) nano composite have studied the morphology and electrochemical properties. The composite is characterized by X-ray diffraction (XRD) and surface morphology was studied using FESEM and electrochemical behavior is studied using cyclic voltammetry (CV) technique. The CV curves shows rectangular shaped curve and they have contribution to electrical double layer capacitance (EDCL).

Colloidally stable surface-modified iron oxide nanoparticles: Preparation, characterization and anti-tumor activity

NASA Astrophysics Data System (ADS)

Macková, Hana; Horák, Daniel; Donchenko, Georgiy Viktorovich; Andriyaka, Vadim Ivanovich; Palyvoda, Olga Mikhailovna; Chernishov, Vladimir Ivanovich; Chekhun, Vasyl Fedorovich; Todor, Igor Nikolaevich; Kuzmenko, Oleksandr Ivanovich

2015-04-01

Maghemite (γ-Fe2O3) nanoparticles were obtained by co-precipitation of Fe(II) and Fe(III) chlorides and subsequent oxidation with sodium hypochlorite and coated with poly(N,N-dimethylacrylamide-co-acrylic acid) [P(DMAAm-AA)]. They were characterized by a range of methods including transmission electron microscopy (TEM), elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The effect of superparamagnetic P(DMAAm-AA)-γ-Fe2O3 nanoparticles on oxidation of blood lipids, glutathione and proteins in blood serum was detected using 2-thiobarbituric acid and the ThioGlo fluorophore. Finally, mice received magnetic nanoparticles administered per os and the antitumor activity of the particles was tested on Lewis lung carcinoma (LLC) in male mice line C57BL/6 as an experimental in vivo metastatic tumor model; the tumor size was measured and the number of metastases in lungs was determined. Surface-modified γ-Fe2O3 nanoparticles showed higher antitumor and antimetastatic activities than commercial CuFe2O4 particles and the conventional antitumor agent cisplatin.

Electrochemical determination of L-phenylalanine at polyaniline modified carbon electrode based on β-cyclodextrin incorporated carbon nanotube composite material and imprinted sol-gel film.

PubMed

Hu, Yu-fang; Zhang, Zhao-hui; Zhang, Hua-bin; Luo, Li-juan; Yao, Shou-zhuo

2011-04-15

A sensitive and selective electrochemical sensor based on a polyaniline modified carbon electrode for the determination of L-phenylalanine has been proposed by utilizing β-cyclodextrin (β-CD) incorporated multi-walled carbon nanotube (MWNT) and imprinted sol-gel film. The electrochemical behavior of the sensor towards L-phenylalanine was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometric i-t curve. The surface morphologies of layer-by-layer assembly electrodes were displayed by scanning electron microscope (SEM). The response mechanism of the imprinted sensor for L-phenylalanine was based on the inclusion interaction of β-CD and molecular recognition capacity of the imprinted film for L-phenylalanine. A linear calibration plot was obtained covering the concentration range from 5.0 × 10(-7) to 1.0 × 10(-4) mol L(-1) with a detection limit of 1.0 × 10(-9) mol L(-1). With excellent sensitivity, selectivity, stability, reproducibility and recovery, the electrochemical imprinted sensor was used to detect L-phenylalanine in blood plasma samples successfully. Copyright © 2011 Elsevier B.V. All rights reserved.

Impacts of bridging complexation on the transport of surface-modified nanoparticles in saturated sand

USDA-ARS?s Scientific Manuscript database

The transport of polyacrylic acid capped cadmium telluride (CdTe) quantum dots (QDs) and carboxylate-modified latex (CML) nanoparticles (NPs) was studied in packed columns at various electrolyte concentrations and cation types. The breakthrough curves (BTCs) of QDs and CML NPs in acid-treated Accus...

Enhanced Gene and siRNA Delivery by Polycation-Modified Mesoporous Silica Nanoparticles Loaded with Chloroquine

PubMed Central

Bhattarai, Shanta Raj; Muthuswamy, Elayaraja; Wani, Amit; Brichacek, Michal; Castañeda, Antonio L.; Brock, Stephanie L.

2014-01-01

Purpose To prepare mesoporous silica-based delivery systems capable of simultaneous delivery of drugs and nucleic acids. Methods The surface of mesoporous silica nanoparticles (MSN) was modified with poly(ethylene glycol) (PEG) and poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA) or poly (2-(diethylamino)ethylmethacrylate) (PDEAEMA). The particles were then loaded with a lysosomotropic agent chloroquine (CQ) and complexed with plasmid DNA or siRNA. The ability of the synthesized particles to deliver combinations of CQ and nucleic acids was evaluated using luciferase plasmid DNA and siRNA targeting luciferase and GAPDH. Results The results show a slow partial MSN dissolution to form hollow silica nanoparticles in aqueous solution. The biological studies show that polycation-modified MSN are able to simultaneously deliver CQ with DNA and siRNA. The co-delivery of CQ and the nucleic acids leads to a significantly increased transfection and silencing activity of the complexes compared with MSN not loaded with CQ. Conclusion PEGylated MSN modified with polycations are promising delivery vectors for combination drug/nucleic acid therapies. PMID:20730557

Immobilization of Magnetic Nanoparticles onto Amine-Modified Nano-Silica Gel for Copper Ions Remediation

PubMed Central

Elkady, Marwa; Hassan, Hassan Shokry; Hashim, Aly

2016-01-01

A novel nano-hybrid was synthesized through immobilization of amine-functionalized silica gel nanoparticles with nanomagnetite via a co-precipitation technique. The parameters, such as reagent concentrations, reaction temperature and time, were optimized to accomplish the nano-silica gel chelating matrix. The most proper amine-modified silica gel nanoparticles were immobilized with magnetic nanoparticles. The synthesized magnetic amine nano-silica gel (MANSG) was established and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). The feasibility of MANSG for copper ions’ remediation from wastewater was examined. MANSG achieves a 98% copper decontamination from polluted water within 90 min. Equilibrium sorption of copper ions onto MANSG nanoparticles obeyed the Langmuir equation compared to the Freundlich, Temkin, Elovich and Dubinin-Radushkevich (D-R) equilibrium isotherm models. The pseudo-second-order rate kinetics is appropriate to describe the copper sorption process onto the fabricated MANSG. PMID:28773583

A nonfouling voltammetric immunosensor for the carcinoembryonic antigen based on the use of polyaniline nanowires wrapped with hyaluronic acid.

PubMed

Wang, Jiasheng; Hui, Ni

2018-06-16

A non-fouling electrochemical immunosensor is described for determination of the tumor biomarker carcinoembryonic antigen (CEA). It is based on the use of composite wires made by chemical grafting of hyaluronic acid onto polyaniline nanowires. The modified nanowires possess excellent antifouling property both in single protein solutions and in dilute serum samples. The current of immunoelectrode exhibits a linear response in the 0.01 pg mL -1 to 10,000 pg mL -1 CEA concentration range and 0.0075 pg mL -1 detection limit. This work demonstrates that coating an electrode with hyaluronic acid can largely reduce unspecific adsorption of proteins on the electrode surface. Graphical abstract Schematic of a nonfouling electrochemical immunosensor for the carcinoembryonic antigen. It is based on novel composite wires made through the chemical grafting of easily available hyaluronic acid (HA) onto polyaniline (PANI) nanowires. The HA/PANI demonstrated excellent antifouling property both in single protein solutions and human serum samples.

Enhanced Supercapacitor Performance Using Electropolymerization of Self-Doped Polyaniline on Carbon Film.

PubMed

Wang, Po-Hsin; Wang, Tzong-Liu; Lin, Wen-Churng; Lin, Hung-Yin; Lee, Mei-Hwa; Yang, Chien-Hsin

2018-03-31

In this work, we electrochemically deposited self-doped polyanilines (SPANI) on the surface of carbon-nanoparticle (CNP) film, enhancing the superficial faradic reactions in supercapacitors and thus improving their performance. SPANI was electrodeposited on the CNP-film employing electropolymerization of aniline (AN) and o-aminobenzene sulfonic acid (SAN) comonomers in solution. Here, SAN acts in dual roles of a self-doped monomer while it also provides an acidic environment which is suitable for electropolymerization. The performance of SPANI-CNP-based supercapacitors significantly depends upon the mole ratio of AN/SAN. Supercapacitor performance was investigated by using cyclic voltammetry (CV), galvanostatic charge and discharge (GCD), and electrochemical impedance spectroscopy (EIS). The optimal performance of SPANI-CNP-based supercapacitor exists at AN/SAN ratio of 1.0, having the specific capacitance of 273.3 Fg -1 at the charging current density of 0.5 Ag -1 .

Deposition of gold nano-particles and nano-layers on polyethylene modified by plasma discharge and chemical treatment

NASA Astrophysics Data System (ADS)

Švorčík, V.; Chaloupka, A.; Záruba, K.; Král, V.; Bláhová, O.; Macková, A.; Hnatowicz, V.

2009-08-01

Polyethylene (PE) was treated in Ar plasma discharge and then grafted from methanol solution of 1,2-ethanedithiol to enhance adhesion of gold nano-particles or sputtered gold layers. The modified PE samples were either immersed into freshly prepared colloid solution of Au nano-particles or covered by sputtered, 50 nm thick gold nano-layer. Properties of the plasma modified, dithiol grafted and gold coated PE were studied using XPS, UV-VIS, AFM, EPR, RBS methods and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain, creation of excessive free radicals and conjugated double bonds. After grafting with 1,2-ethanedithiol the concentration of free radicals declined but the concentration of double bonds remained unchanged. Plasma treatment changes PE surface morphology and increases surface roughness too. Another significant change in the surface morphology and roughness was observed after deposition of Au nano-particles. The presence of Au on the sample surface after the coating with Au nano-particles was proved by XPS and RBS methods. Nanoindentation measurements shown that the grafting of plasma activated PE surface with dithiol increases significantly adhesion of sputtered Au nano-layer.

Sorption and Diffusion of Water Vapor and Carbon Dioxide in Sulfonated Polyaniline as Chemical Sensing Materials.

PubMed

Liang, Qiuhua; Jiang, Junke; Ye, Huaiyu; Yang, Ning; Cai, Miao; Xiao, Jing; Chen, Xianping

2016-04-27

A hybrid quantum mechanics (QM)/molecular dynamics (MD) simulation is performed to investigate the effect of an ionizable group (-SO₃(-)Na⁺) on polyaniline as gas sensing materials. Polymers considered for this work include emeraldine base of polyaniline (EB-PANI) and its derivatives (Na-SPANI (I), (II) and (III)) whose rings are partly monosubstituted by -SO₃(-)Na⁺. The hybrid simulation results show that the adsorption energy, Mulliken charge and band gap of analytes (CO₂ and H₂O) in polyaniline are relatively sensitive to the position and the amounts of -SO₃(-)Na⁺, and these parameters would affect the sensitivity of Na-SPANI/EB-PANI towards CO₂. The sensitivity of Na-SPANI (III)/EB-PANI towards CO₂ can be greatly improved by two orders of magnitude, which is in agreement with the experimental study. In addition, we also demonstrate that introducing -SO₃(-)Na⁺ groups at the rings can notably affect the gas transport properties of polyaniline. Comparative studies indicate that the effect of ionizable group on polyaniline as gas sensing materials for the polar gas molecule (H₂O) is more significant than that for the nonpolar gas molecule (CO₂). These findings contribute in the functionalization-induced variations of the material properties of polyaniline for CO₂ sensing and the design of new polyaniline with desired sensing properties.

Preparation of transition metal nanoparticles and surfaces modified with (CO)polymers synthesized by RAFT

DOEpatents

McCormick, III., Charles L.; Lowe, Andrew B.; Sumerlin, Brent S.

2006-11-21

A new, facile, general one-phase method of generating thio-functionalized transition metal nanoparticles and surfaces modified by (co)polymers synthesized by the RAFT method is described. The method includes the stops of forming a (co)polymer in aqueous solution using the RAFT methodology, forming a colloidal transition metal precursor solution from an appropriate transition metal; adding the metal precursor solution or surface to the (co)polymer solution, adding a reducing agent into the solution to reduce the metal colloid in situ to produce the stabilized nanoparticles or surface, and isolating the stabilized nanoparticles or surface in a manner such that aggregation is minimized. The functionalized surfaces generated using these methods can further undergo planar surface modifications, such as functionalization with a variety of different chemical groups, expanding their utility and application.

Preparation of transition metal nanoparticles and surfaces modified with (co)polymers synthesized by RAFT

DOEpatents

McCormick, III, Charles L.; Lowe, Andrew B [Hattiesburg, MS; Sumerlin, Brent S [Pittsburgh, PA

2011-12-27

A new, facile, general one-phase method of generating thiol-functionalized transition metal nanoparticles and surfaces modified by (co)polymers synthesized by the RAFT method is described. The method includes the steps of forming a (co)polymer in aqueous solution using the RAFT methodology, forming a colloidal transition metal precursor solution from an appropriate transition metal; adding the metal precursor solution or surface to the (co)polymer solution, adding a reducing agent into the solution to reduce the metal colloid in situ to produce the stabilized nanoparticles or surface, and isolating the stabilized nanoparticles or surface in a manner such that aggregation is minimized. The functionalized surfaces generated using these methods can further undergo planar surface modifications, such as functionalization with a variety of different chemical groups, expanding their utility and application.

Biological pH sensing based on the environmentally friendly Raman technique through a polyaniline probe.

PubMed

Li, Songyang; Liu, Zhiming; Su, Chengkang; Chen, Haolin; Fei, Xixi; Guo, Zhouyi

2017-02-01

The biological pH plays an important role in various cellular processes. In this work, a novel strategy is reported for biological pH sensing by using Raman spectroscopy and polyaniline nanoparticles (PANI NPs) as the pH-sensitive Raman probe. It is found that the Raman spectrum of PANI NPs is strongly dependent on the pH value. The intensities of Raman spectral bands at 1225 and 1454 cm -1 increase obviously with pH value varying from 5.5 to 8.0, which covers the range of regular biological pH variation. The pH-dependent Raman performance of PANI NPs, as well as their robust Raman signals and sensitivities to pH, was well retained after the nanoparticles incorporated into living 4T1 breast adenocarcinoma cells. The data indicate that such PANI NPs can be used as an effective biological pH sensor. Most interestingly, the PANI spherical nanostructures can be acquired by a low-cost, metal-free, and one-pot oxidative polymerization, which gives them excellent biocompatibility for further biological applications.

The sorption of influenza viruses and antibiotics on carbon nanotubes and polyaniline nanocomposites

NASA Astrophysics Data System (ADS)

Ivanova, V. T.; Katrukha, G. S.; Timofeeva, A. V.; Ilyna, M. V.; Kurochkina, Y. E.; Baratova, L. A.; Sapurina, I. Yu; Ivanov, V. F.

2011-04-01

The decontamination of the solutions from micropatogens and drug delivery are the important problems of modern life. It was shown that carbon nanotubes, polyaniline and their composites can interact with antibiotics-polypeptides and some viruses (pandemic strain of influenza viruses A(H1N1)v circulated in Russia in 2009-2010. During a short time drug and viruses can be absorbed by polyaniline and removed from aqueous solutions at the normal conditions. Polyaniline composites can be useful for the preparation of drug delivery and virus control filters and also in biotechnology for the improvement the methods of antibiotics purification.

Detection of aniline oligomers on polyaniline-gold interface using resonance Raman scattering.

PubMed

Trchová, Miroslava; Morávková, Zuzana; Dybal, Jiří; Stejskal, Jaroslav

2014-01-22

In situ deposited conducting polyaniline films prepared by the oxidation of aniline with ammonium peroxydisulfate in aqueous media of various acidities on gold and silicon supports were characterized by Raman spectroscopy. Enhanced Raman bands were found in the spectra of polyaniline films produced in the solutions of weak acids or in water on gold surface. These bands were weak for the films prepared in solutions of a strong acid on a gold support. The same bands are present in the Raman spectra of the reaction intermediates deposited during aniline oxidation in water or aqueous solutions of weak or strong acids on silicon removed from the reaction mixture at the beginning of the reaction. Such films are formed by aniline oligomers adsorbed on the surface. They were detected on the polyaniline-gold interface using resonance Raman scattering on the final films deposited on gold. The surface resonance Raman spectroscopy of the monolayer of oligomers found in the bulk polyaniline film makes this method advantageous in surface science, with many applications in electrochemistry, catalysis, and biophysical, polymer, or analytical chemistry.

First-principles study of the effect of functional groups on polyaniline backbone

PubMed Central

Chen, X. P.; Jiang, J. K.; Liang, Q. H.; Yang, N.; Ye, H. Y.; Cai, M.; Shen, L.; Yang, D. G.; Ren, T. L.

2015-01-01

We present a first-principles density functional theory study focused on how the chemical and electronic properties of polyaniline are adjusted by introducing suitable substituents on a polymer backbone. Analyses of the obtained energy barriers, reaction energies and minimum energy paths indicate that the chemical reactivity of the polyaniline derivatives is significantly enhanced by protonic acid doping of the substituted materials. Further study of the density of states at the Fermi level, band gap, HOMO and LUMO shows that both the unprotonated and protonated states of these polyanilines are altered to different degrees depending on the functional group. We also note that changes in both the chemical and electronic properties are very sensitive to the polarity and size of the functional group. It is worth noting that these changes do not substantially alter the inherent chemical and electronic properties of polyaniline. Our results demonstrate that introducing different functional groups on a polymer backbone is an effective approach to obtain tailored conductive polymers with desirable properties while retaining their intrinsic properties, such as conductivity. PMID:26584671

Preparation and dielectric properties of novel composites based on oxidized styrene-butadienestyrene copolymer and polyaniline modified exfoliated graphite nanoplates

NASA Astrophysics Data System (ADS)

Lv, Qun-Chen; Li, Ying; Zhong, Zhi-Kui; Wu, Hui-Jun; He, Fu-An; Lam, Kwok-Ho

2018-05-01

To improve the dielectric performance of high-dielectric-constant conductive filler/polymer composites, polyaniline was deposited on exfoliated graphite nanoplates (xGNPs) by in-situ polymerization method to form polyaniline (PANI) coated xGNPs (xGNPs@PANI) as the conductive filler for the oxidized styrene-butadienestyrene copolymer (SBS-FH) containing both hydroxyl and formyloxy groups. The results of TEM, SEM, FTIR, TGA, Raman spectrum, XPS, and WAXD showed that PANI had been coated onto the surface of xGNPs successfully. The xGNPs@PANI/SBS-FH composites were prepared by a simple solution-blending method and the homogenous distribution of xGNPs@PANI in the SBS-FH matrix was confirmed by SEM. The presence of xGNPs@PANI was found to significantly improve the dielectric properties of resultant composite compared to the unmodified xGNPs. For example, the xGNPs@PANI/SBS-FH composite near percolation threshold filled with 9.38 vol.% xGNPs@PANI showed a dielectric constant of 56.8 and a dielectric loss factor of 0.51 at 1000 Hz, while the corresponding values of xGNPs (1.19 vol.%)/SBS composite were 15.96 and 2.91 at 1000 Hz, respectively. In addition, the incorporation of xGNPs@PANI into SBS-FH could effectively enhance the thermal conductivity of resultant xGNPs@PANI/SBS-FH composite.

Multifunctional organically modified silica nanoparticles for chemotherapy, adjuvant hyperthermia and near infrared imaging.

PubMed

Nagesetti, Abhignyan; McGoron, Anthony J

2016-11-01

We report a novel system of organically modified silica nanoparticles (Ormosil) capable of near infrared fluorescence and chemotherapy with adjuvant hyperthermia for image guided cancer therapy. Ormosil nanoparticles were loaded with a chemotherapeutic, Doxorubicin (DOX) and cyanine dye, IR820. Ormosil particles had a mean diameter of 51.2±2.4 nanometers and surface charge of -40.5±0.8mV. DOX was loaded onto Ormosil particles via physical adsorption (FDSIR820) or covalent linkage (CDSIR820) to the silanol groups on the Ormosil surface. Both formulations retained DOX and IR820 over a period of 2 days in aqueous buffer, though CDSIR820 retained more DOX (93.2%) compared to FDSIR820 (77.0%) nanoparticles. Exposure to near infrared laser triggered DOX release from CDSIR820. Uptake of nanoparticles was determined by deconvolution microscopy in ovarian carcinoma cells (Skov-3). CDSIR820 localized in the cell lysosomes whereas cells incubated with FDSIR820 showed DOX fluorescence from the nucleus indicating leakage of DOX from the nanoparticle matrix. FDSIR820 nanoparticles showed severe toxicity in Skov-3 cells whereas CDSIR820 particles had the same cytotoxicity profile as bare (No DOX and IR820) Ormosil particles. Furthermore, exposure of CDSIR820 nanoparticles to Near Infrared laser at 808 nanometers resulted in generation of heat (to 43°C from 37°C) and resulted in enhanced cell killing compared to Free DOX treatment. Bio-distribution studies showed that CDSIR820 nanoparticles were primarily present in the organs of Reticuloendothelial (RES) system. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of Industrial Polyurethane Foams Modified with Antimicrobial Copper Nanoparticles

PubMed Central

Sportelli, Maria Chiara; Picca, Rosaria Anna; Ronco, Roberto; Bonerba, Elisabetta; Tantillo, Giuseppina; Pollini, Mauro; Sannino, Alessandro; Valentini, Antonio; Cataldi, Tommaso R.I.; Cioffi, Nicola

2016-01-01

Antimicrobial copper nanoparticles (CuNPs) were electrosynthetized and applied to the controlled impregnation of industrial polyurethane foams used as padding in the textile production or as filters for air conditioning systems. CuNP-modified materials were investigated and characterized morphologically and spectroscopically, by means of Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The release of copper ions in solution was studied by Electro-Thermal Atomic Absorption Spectroscopy (ETAAS). Finally, the antimicrobial activity of freshly prepared, as well as aged samples—stored for two months—was demonstrated towards different target microorganisms. PMID:28773665

Isolation and characterisation of nanoparticles from tef and maize starch modified with stearic acid.

PubMed

Cuthbert, Wokadala O; Ray, Suprakas S; Emmambux, Naushad M

2017-07-15

Nanoparticles were isolated from tef and maize starch modified with added stearic acid after pasting at 90°C for 130min. This was followed by thermo-stable alpha-amylase hydrolysis of the paste. The resultant residues were then characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic laser scattering particle size distribution (DLPSD), atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). XRD and DSC showed that the isolated residues consisted of amylose-lipid complexes. These complexes were type II with melting temperature above 104°C. DLPSD, AFM and HRTEM showed that the isolated tef and maize starch residues consisted of nanoparticles which became more distinct with increased hydrolysis time. The isolated tef and maize nanoparticles had distinct particles of about 3-10nm and 2.4-6.7nm, respectively and the yield was about 24-30%. The results demonstrated that distinct (physically separate) nanoparticles of less than 10nm can be isolated after formation during pasting of tef and maize starch with stearic acid. The production and isolation of the nanoparticles uses green chemistry principles and these nanoparticles can be used in food and non-food systems as nanofillers. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Enzyme Switch Employing Direct Electrochemical Communication between Horseradish Peroxidase and a Poly(aniline) Film.

PubMed

Bartlett, P N; Birkin, P R; Wang, J H; Palmisano, F; De Benedetto, G

1998-09-01

An enzyme switch, or microelectrochemical enzyme transistor, responsive to hydrogen peroxide was made by connecting two carbon band electrodes (∼10 μm wide, 4.5 mm long separated by a 20-μm gap) with an anodically grown film of poly(aniline). Horseradish peroxidase (EC 1.11.1.7) was either adsorbed onto the poly(aniline) film or immobilized in an insulating poly(1,2-diaminobenzene) polymer grown electrochemically on top of the poly(aniline) film to complete the device. In the completed device, the conductivity of the poly(aniline) film changes from conducting (between - 0.05 and + 0.3 V vs SCE at pH 5) to insulating (>+0.3 V vs SCE at pH 5) on addition of hydrogen peroxide. The change in conductivity is brought about by oxidation of the poly(aniline) film by direct electrochemical communication between the enzyme and the conducting polymer. This was confirmed by measuring the potential of the poly(aniline) film during switching of the conductivity in the presence of hydrogen peroxide. The devices can be reused by rereducing the poly(aniline) electrochemically to a potential below +0.3 V vs SCE. A blind test showed that the device can be used to determine unknown concentrations of H(2)O(2) in solution and that, when used with hydrogen peroxide concentrations below 0.5 mmol dm(-)(3), the same device maybe reused several times. The possible development of devices of this type for use in applications requiring the measurement of low levels of hydrogen peroxide or horseradish peroxidase is discussed.

Potential of polyaniline modified clay nanocomposite as a selective decontamination adsorbent for Pb(II) ions from contaminated waters; kinetics and thermodynamic study.

PubMed

Piri, Somayeh; Zanjani, Zahra Alikhani; Piri, Farideh; Zamani, Abbasali; Yaftian, Mohamadreza; Davari, Mehdi

2016-01-01

Nowadays significant attention is to nanocomposite compounds in water cleaning. In this article the synthesis and characterization of conductive polyaniline/clay (PANI/clay) as a hybrid nanocomposite with extended chain conformation and its application for water purification are presented. Clay samples were obtained from the central plain of Abhar region, Abhar, Zanjan Province, Iran. Clay was dried and sieved before used as adsorbent. The conductive polyaniline was inflicted into the layers of clay to fabricate a hybrid material. The structural properties of the fabricated nanocomposite are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The elimination process of Pb(II) and Cd(II) ions from synthetics aqueous phase on the surface of PANI/clay as adsorbent were evaluated in batch experiments. Flame atomic absorption instrument spectrophotometer was used for determination of the studied ions concentration. Consequence change of the pH and initial metal amount in aqueous solution, the procedure time and the used adsorbent dose as the effective parameters on the removal efficiency was investigated. Surface characterization was exhibited that the clay layers were flaked in the hybrid nanocomposite. The results show that what happen when a nanocomposite polyaniline chain is inserted between the clay layers. The adsorption of ions confirmed a pH dependency procedure and a maximum removal value was seen at pH 5.0. The adsorption isotherm and the kinetics of the adsorption processes were described by Temkin model and pseudo-second-order equation. Time of procedure, pH and initial ion amount have a severe effect on adsorption efficiency of PANI/clay. By using suggested synthesise method, nano-composite as the adsorbent simply will be prepared. The prepared PANI/clay showed excellent adsorption capability for decontamination of Pb ions from contaminated water. Both of suggested synthesise and

Nanoparticles Affect PCR Primarily via Surface Interactions with PCR Components: Using Amino-Modified Silica-Coated Magnetic Nanoparticles as a Main Model.

PubMed

Bai, Yalong; Cui, Yan; Paoli, George C; Shi, Chunlei; Wang, Dapeng; Shi, Xianming

2015-06-24

Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic nanoparticles (ASMNPs, which can be collected very easily using an external magnetic field) as a model and compared them with gold nanoparticles (AuNPs, which have been studied extensively) to reveal the mechanisms by which nanoparticles affect PCR. We found that nanoparticles affect PCR primarily by binding to PCR components: (1) inhibition, (2) specifity, and (3) efficiency and yield of PCR are impacted. (1) Excess nanomaterials inhibit PCR by adsorbing to DNA polymerase, Mg(2+), oligonucleotide primers, or DNA templates. Nanoparticle surface-active groups are particularly important to this effect. (2, a) Nanomaterials do not inhibit nonspecific amplification products caused by false priming as previously surmised. It was shown that relatively low concentrations of nanoparticles inhibited the amplification of long amplicons, and increasing the amount of nanoparticles inhibited the amplification of short amplicons. This concentration phenomenon appears to be the result of the formation of "joints" upon the adsorption of ASMNPs to DNA templates. (b) Nanomaterials are able to inhibit nonspecific amplification products due to incomplete amplification by preferably adsorbing single-stranded incomplete amplification products. (3) Some types of nanomaterials, such as AuNPs, enhance the efficiency and yield of PCR because these types of nanoparticles can adsorb to single-stranded DNA more strongly than to double-stranded DNA. This behavior assists in the rapid and thorough denaturation of double-stranded DNA templates. Therefore, the interaction between the surface of nanoparticles and PCR components is sufficient to explain most of the effects of nanoparticles on PCR.

Use of Cu+1 dopant and it's doping effects on polyaniline conducting system in water and tetrahydrofuran

NASA Astrophysics Data System (ADS)

Ali, Vazid; Kaur, Raminder; Kamal, Neel; Singh, Sukhmehar; Jain, S. C.; Kang, H. P. S.; Zulfequar, M.; Husain, M.

2006-04-01

The structural modification and properties of polymeric materials are of utmost importance in deciding their applications. In the present study, the synthesis of polyaniline (PANI) has been carried out via chemical oxidation in acidic medium by potassium-dichromate and the yield of synthesized polyaniline was found to be 75 80%. The copper per chlorate tetrabenzonitrile salt (CuClO4·4BN) used for chemical doping in synthesized polyaniline is stable in organic solvent like acetonitrile (AN) and benzonitrile (BN). The effect of Cu+1 oxidation state (dopant) in polyaniline has been characterized by FTIR. Electrical and dielectric measurements show the decrease in the intensity of the Cu+1 salt signal and the appearance of a radical signal due to the formation of oxidative coupled in polymeric species. Electrical and dielectric properties of doped polyaniline samples show significant changes due to the effect of dopant (CuClO4·4BN). It is observed that the conductivity is contributing both by formation of ionic complex and particularly dominated by electronic due to the mobility of charge carriers along the polyaniline chain.

Development of Cy5.5-Labeled Hydrophobically Modified Glycol Chitosan Nanoparticles for Protein Delivery

NASA Astrophysics Data System (ADS)

Chin, Amanda

Therapeutic proteins are often highly susceptible to enzymatic degradation, thus restricting their in vivo stability. To overcome this limitation, delivery systems designed to promote uptake and reduce degradation kinetics have undergone a rapid shift from macro-scale systems to nanomaterial based carriers. Many of these nanomaterials, however, elicit immune responses and may have cytotoxic effects both in vitro and in vivo. The naturally derived polysaccharide chitosan has emerged as a promising biodegradable material and has been utilized for many biomedical applications; nevertheless, its function is often constrained by poor solubility. Glycol chitosan, a derivative of chitosan, can be hydrophobically modified to impart amphiphilic properties that enable the self-assembly into nanoparticles in aqueous media at neutral pH. This nanoparticle system has shown initial success as a therapeutic agent in several model cell culture systems, but little is known about its stability against enzymatic degradation. Therefore, the goal of this research was to investigate the resistance of hydrophobically modified glycol chitosan against enzyme-catalyzed degradation using an in vivo simulated system containing lysozyme. To synthesize the nanoparticles, hydrophobic cholanic acid was first covalently conjugated to glycol chitosan using of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Conjugates were purified by dialysis, lyophilized, and ultra-sonicated to form nanoparticles. Fourier transform infrared (FT-IR) spectroscopy confirmed the binding of 5beta-cholanic acid to the glycol chitosan. Particle size and stability over time were determined with dynamic light scattering (DLS), and particle morphology was evaluated by transmission electron microscopy (TEM). The average diameter of the nanoparticles was approximately 200 nm, which remained stable at 4°C for up to 10 days. Additionally, a near infrared fluorescent (NIRF) dye

Sorption and Diffusion of Water Vapor and Carbon Dioxide in Sulfonated Polyaniline as Chemical Sensing Materials

PubMed Central

Liang, Qiuhua; Jiang, Junke; Ye, Huaiyu; Yang, Ning; Cai, Miao; Xiao, Jing; Chen, Xianping

2016-01-01

A hybrid quantum mechanics (QM)/molecular dynamics (MD) simulation is performed to investigate the effect of an ionizable group (–SO3−Na+) on polyaniline as gas sensing materials. Polymers considered for this work include emeraldine base of polyaniline (EB-PANI) and its derivatives (Na-SPANI (I), (II) and (III)) whose rings are partly monosubstituted by –SO3−Na+. The hybrid simulation results show that the adsorption energy, Mulliken charge and band gap of analytes (CO2 and H2O) in polyaniline are relatively sensitive to the position and the amounts of –SO3−Na+, and these parameters would affect the sensitivity of Na-SPANI/EB-PANI towards CO2. The sensitivity of Na-SPANI (III)/EB-PANI towards CO2 can be greatly improved by two orders of magnitude, which is in agreement with the experimental study. In addition, we also demonstrate that introducing –SO3−Na+ groups at the rings can notably affect the gas transport properties of polyaniline. Comparative studies indicate that the effect of ionizable group on polyaniline as gas sensing materials for the polar gas molecule (H2O) is more significant than that for the nonpolar gas molecule (CO2). These findings contribute in the functionalization-induced variations of the material properties of polyaniline for CO2 sensing and the design of new polyaniline with desired sensing properties. PMID:27128921

Electrodeposited polyaniline as a fiber coating for solid-phase microextraction of organochlorine pesticides from water.

PubMed

Li, Xiang; Zhong, Ming; Chen, Jianmin

2008-08-01

The study on the performance of polyaniline as a fiber coating for solid-phase microextraction (SPME) purposes has been reported. Polyaniline coatings were directly electrodeposited on the surface of a stainless steel wire and applied for the extraction of some organochlorine pesticides (OCPs) from water samples. Analyses were performed using GC-electron capture detection (GC-ECD). The results obtained show that polyaniline fiber coating is suitable for the successful extraction of organochlorine compounds. This behavior is most probably due to the porous surface structure of polyaniline film, which provides large surface areas and allowed for high extraction efficiency. Experimental parameters such as adsorption and desorption conditions were studied and optimized. The optimized method has an acceptable linearity, with a concentration range of 1-5000 ng/L. Single fiber repeatability and fiber-to-fiber reproducibility were less than 12 and 17%, respectively. High environmental resistance and lower cost are among the advantages of polyaniline fibers over commercially available SPME fibers. The developed method was applied to the analysis of real water samples from Yangtse River and Tianmu Lake.

Photocatalytic properties of PbS/graphene oxide/polyaniline electrode for hydrogen generation.

PubMed

Shaban, Mohamed; Rabia, Mohamed; El-Sayed, Asmaa M Abd; Ahmed, Aya; Sayed, Somaya

2017-10-26

In this work, roll-graphene oxide (Ro-GO), polyaniline (PANI) nano/microparticles, and PbS nanoparticles were prepared by modified Hammer, oxidative polymerization, and chemical bath deposition methods, respectively. These nano/microstructures were characterized, optimized, and designed to form PbS/Ro-GO/PANI nano/microcomposite. Also, the ratios of PbS and Ro-GO were optimized, and the optimized composition of the used composite was 0.4 g PANI, 0.125 g Ro-GO, and 0.075 g PbS. The band gap values for PANI, PbS, Ro-GO, and PbS/Ro-GO/PANI rocomposite were 3, 1.13, 2.86, (1.16, 2) eV, respectively. Two photoelectrode assemblies, Au/PbS/Ro-GO/PANI and PbS/Ro-GO/PANI/ITO/glass were used for the photoelectrochemical (PEC) hydrogen generation. In the first assembly 45 nm- Au layer was sputtered on the surface of a disk of PbS/Ro-GO/PANI composite. For the second assembly, a disk of PbS/Ro-GO/PANI composite was glued on ITO glass using Ag-THF paste. The lifetime efficiency values were 64.2 and 43.4% for the first and second electrode for 2 h, respectively. Finally, the incident photon-to-current conversion efficiency (IPCE) and photon-to-current efficiency (ABPE) were calculated under monochromatic illumination conditions. The optimum IPCE efficiency at 390 nm was 9.4% and 16.17%, whereas ABPE % efficiency was 1.01% and 1.75% for Au/PbS/Ro-GO/PANI and PbS/Ro-GO/PANI/ITO/glass, respectively.

Doping effect of polyaniline/MWCNT composites on capacitance and cyclic stability of supercapacitors.

PubMed

Karthikeyan, G; Sahoo, S; Nayak, G C; Das, C K

2012-03-01

Polyaniline doped by Zn2+ ions was synthesized as nanocomposites with multiwalled carbon nanotubes (MWCNT) by in-situ oxidative polymerization and investigated as electrode material for supercapacitors. The uniform coating of polyaniline on MWCNT was characterized by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The effect of Zn2+ ions on nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical performances were investigated by cyclic voltammetry (CV), constant current charging/discharging cyclic test (CC) and electrochemical impedance spectroscopy (EIS) using a three-electrode system. The doped polyaniline composites show higher specific capacitance and better cyclic stability.

Electrospun Polyaniline/Polyethylene Oxide Nanofiber Field Effect Transistor

NASA Technical Reports Server (NTRS)

Pinto, N. J.; Johnson, A. T.; MacDiarmid, A. G.; Mueller, C. H.; Theofylaktos, N.; Robinson, D. C.; Miranda, F. A.

2003-01-01

We report on the observation of field effect transistor (FET) behavior in electrospun camphorsulfonic acid doped polyaniline(PANi)/polyethylene oxide(PE0) nanofibers. Saturation channel currents are observed at surprisingly low source/drain voltages. The hole mobility in the depletion regime is 1.4 x 10(exp -4) sq cm/V s while the 1-D charge density (at zero gate bias) is calculated to be approximately 1 hole per 50 two-ring repeat units of polyaniline, consistent with the rather high channel conductivity (approx. 10(exp -3) S/cm). Reducing or eliminating the PEO content in the fiber is expected to enhance device parameters. Electrospinning is thus proposed as a simple method of fabricating 1-D polymer FET's.

Synthesis of polyaniline/cellulose composite as humidity sensor

NASA Astrophysics Data System (ADS)

Putri, N. P.; Kusumawati, D. H.; Widiyanti, N.; Munasir

2018-03-01

Water hyacinth is one weed plant that has cellulose content of 60% on the stem and is a good absorbent. in this study cellulose extraction from hyacinth has been done through several stages. Polyaniline/cellulose composite (PANi/cellulose) is prepared by an in-situ chemical method using cupric sulphate as an initiator. The representative PANi/cellulose samples are characterized by Fourier Transform Infrared (FTIR). On comparing it appears that spectra PANi/cellulose contains vibrational bands due to both PANi and cellulose. This may indicate the formation of PANi/cellulose composite. From the resistance measurement results, it can be seen that with the addition of cellulose to PANi can improve the sensitivity of the polyaniline based moisture sensor

Local Charge Injection and Extraction on Surface-Modified Al2O3 Nanoparticles in LDPE.

PubMed

Borgani, Riccardo; Pallon, Love K H; Hedenqvist, Mikael S; Gedde, Ulf W; Haviland, David B

2016-09-14

We use a recently developed scanning probe technique to image with high spatial resolution the injection and extraction of charge around individual surface-modified aluminum oxide nanoparticles embedded in a low-density polyethylene (LDPE) matrix. We find that the experimental results are consistent with a simple band structure model where localized electronic states are available in the band gap (trap states) in the vicinity of the nanoparticles. This work offers experimental support to a previously proposed mechanism for enhanced insulating properties of nanocomposite LDPE and provides a powerful experimental tool to further investigate such properties.

Flame retardancy of polyaniline-deposited paper composites prepared via in situ polymerization.

PubMed

Wu, Xianna; Qian, Xueren; An, Xianhui

2013-01-30

Polyaniline-deposited paper composites doped with three inorganic acids were prepared via in situ polymerization, and their flame-retardant properties were investigated. Both the conductivity and flame retardancy of the composite increased with the increase of the amount of the polyaniline deposited. The doping acid played a very key role in both the conductivity and flame retardancy of the composite. The comprehensive properties of the composite could be improved when codoped with an equimolar mixture of H(3)PO(4) and H(2)SO(4) or H(3)PO(4) and HCl. The decay of the flame retardancy of the composite in atmosphere was due to the dedoping of the polyaniline deposited on cellulose fibers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Silver-nanoparticles-modified biomaterial surface resistant to staphylococcus: new insight into the antimicrobial action of silver

PubMed Central

Wang, Jiaxing; Li, Jinhua; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Zhao, Yaochao; Qin, Hui; Wahafu, Tuerhongjiang; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong

2016-01-01

Titanium implants are widely used clinically, but postoperative implant infection remains a potential severe complication. The purpose of this study was to investigate the antibacterial activity of nano-silver(Ag)-functionalized Ti surfaces against epidemic Staphylococcus from the perspective of the regulation of biofilm-related genes and based on a bacteria-cell co-culture study. To achieve this goal, two representative epidemic Staphylococcus strains, Staphylococcus epidermidis (S. epidermidis, RP62A) and Staphylococcus aureus (S. aureus, USA 300), were used, and it was found that an Ag-nanoparticle-modified Ti surface could regulate the expression levels of biofilm-related genes (icaA and icaR for S. epidermidis; fnbA and fnbB for S. aureus) to inhibit bacterial adhesion and biofilm formation. Moreover, a novel bacteria-fibroblast co-culture study revealed that the incorporation of Ag nanoparticles on such a surface can help mammalian cells to survive, adhere and spread more successfully than Staphylococcus. Therefore, the modified surface was demonstrated to possess a good anti-infective capability against both sessile bacteria and planktonic bacteria through synergy between the effects of Ag nanoparticles and ion release. This work provides new insight into the antimicrobial action and mechanism of Ag-nanoparticle-functionalized Ti surfaces with bacteria-killing and cell-assisting capabilities and paves the way towards better satisfying the clinical needs. PMID:27599568

Effect of polyvinylpyrrolidone content on alternating current conductivity of polyaniline

NASA Astrophysics Data System (ADS)

Megha, R.; Kumar, T. G. Naveen; Ravikiran, Y. T.; Prakash, H. G. Raj; Revanasiddappa, M.; Kumari, S. C. Vijaya

2018-05-01

In the present work, Polyaniline (PANI) and Polyaniline-polyvinylpyrrolidone (PANI-PVP) composites of two different weight percentages of PVP were synthesized separately by simple chemical polymerization method. The interaction between PANI and PVP in each of the composite was confirmed by Attenuated total reflection infrared spectroscopic (AT-IR) technique. The alternate current (AC) response characteristics at room temperature of PANI and the composites in the frequency range 50 Hz-1 MHz were comparatively studied. Both the composites have shown decreased conductivity as compared to that of PANI.

Enhanced removal of As (V) from aqueous solution using modified hydrous ferric oxide nanoparticles

PubMed Central

Huo, Lijuan; Zeng, Xibai; Su, Shiming; Bai, Lingyu; Wang, Yanan

2017-01-01

Hydrous ferric oxide (HFO) is most effective with high treatment capacity on arsenate [As(V)] sorption although its transformation and aggregation nature need further improvement. Here, HFO nanoparticles with carboxymethyl cellulose (CMC) or starch as modifier was synthesized for the purpose of stability improvement and As(V) removal from water. Comparatively, CMC might be the optimum stabilizer for HFO nanoparticles because of more effective physical and chemical stability. The large-pore structure, high surface specific area, and the non-aggregated nature of CMC-HFO lead to increased adsorption sites, and thus high adsorption capacities of As(V) without pre-treatment (355 mg·g−1), which is much greater than those reported in previous studies. Second-order equation and dual-mode isotherm model could be successfully used to interpret the sorption kinetics and isotherms of As(V), respectively. FTIR, XPS and XRD analyses suggested that precipitation and surface complexation were primary mechanisms for As(V) removal by CMC modified HFO nanoparticles. A surface complexation model (SCM) was used to simulate As adsorption over pH 2.5–10.4. The predominant adsorbed arsenate species were modeled as bidentate binuclear surface complexes at low pH and as monodentate complexes at high pH. The immobilized arsenic remained stable when aging for 270 d at room temperature. PMID:28098196

Enhanced removal of As (V) from aqueous solution using modified hydrous ferric oxide nanoparticles

NASA Astrophysics Data System (ADS)

Huo, Lijuan; Zeng, Xibai; Su, Shiming; Bai, Lingyu; Wang, Yanan

2017-01-01

Hydrous ferric oxide (HFO) is most effective with high treatment capacity on arsenate [As(V)] sorption although its transformation and aggregation nature need further improvement. Here, HFO nanoparticles with carboxymethyl cellulose (CMC) or starch as modifier was synthesized for the purpose of stability improvement and As(V) removal from water. Comparatively, CMC might be the optimum stabilizer for HFO nanoparticles because of more effective physical and chemical stability. The large-pore structure, high surface specific area, and the non-aggregated nature of CMC-HFO lead to increased adsorption sites, and thus high adsorption capacities of As(V) without pre-treatment (355 mg·g-1), which is much greater than those reported in previous studies. Second-order equation and dual-mode isotherm model could be successfully used to interpret the sorption kinetics and isotherms of As(V), respectively. FTIR, XPS and XRD analyses suggested that precipitation and surface complexation were primary mechanisms for As(V) removal by CMC modified HFO nanoparticles. A surface complexation model (SCM) was used to simulate As adsorption over pH 2.5-10.4. The predominant adsorbed arsenate species were modeled as bidentate binuclear surface complexes at low pH and as monodentate complexes at high pH. The immobilized arsenic remained stable when aging for 270 d at room temperature.

Clay/Polyaniline Hybrid through Diazonium Chemistry: Conductive Nanofiller with Unusual Effects on Interfacial Properties of Epoxy Nanocomposites.

PubMed

Jlassi, Khouloud; Chandran, Sarath; Poothanari, Mohammed A; Benna-Zayani, Mémia; Thomas, Sabu; Chehimi, Mohamed M

2016-04-12

The concept of conductive network structure in thermoset matrix without sacrificing the inherent mechanical properties of thermoset polymer (e.g., epoxy) is investigated here using "hairy" bentonite fillers. The latter were prepared through the in situ polymerization of aniline in the presence of 4-diphenylamine diazonium (DPA)-modified bentonite (B-DPA) resulting in a highly exfoliated bentonite-DPA/polyaniline (B-DPA/PANI). The nanocomposite filler was mixed with diglycidyl ether of bisphenol A (DGEBA), and the curing agent (4,4'-diaminodiphenylsulfone) (DDS) at high temperature in order to obtain nanocomposites through the conventional melt mixing technique. The role of B-DPA in the modification of the interface between epoxy and B-DPA/polyaniline (B-DPA/PANI) is investigated and compared with the filler B/PANI prepared without any diazonium modification of the bentonite. Synergistic improvement in dielectric properties and mechanical properties points to the fact that the DPA aryl groups from the diazonium precursor significantly modify the interface by acting as an efficient stress transfer medium. In DPA-containing nanocomposites, unique fibril formation was observed on the fracture surface. Moreover, dramatic improvement (210-220%) in fracture toughness of epoxy composite was obtained with B-DPA/PANI filler as compared to the weak improvement of 20-30% noted in the case of the B/PANI filler. This work shows that the DPA diazonium salt has an important effect on the improvement of the interfacial properties and adhesion of DGEBA and clay/PANI nanofillers.

Embedding of polyaniline molecules on adhesive tape using successive ionic layer adsorption and reaction (SILAR) technique

NASA Astrophysics Data System (ADS)

Pamatmat, J. K.; Gillado, A. V.; Herrera, M. U.

2017-05-01

Polyaniline molecules are embedded on adhesive tape using successive ionic layer adsorption and reaction (SILAR) technique. The infrared spectrum shows the existence of molecular vibrational modes associated with the presence of polyaniline molecules on the sample. With the addition of polyaniline molecules, the conductivity of adhesive tape increases. Surface conductivity increases with number of dipping cycle until it reaches a certain value. Beyond this value, surface conductivity begins to decrease. The surface conductivity of the sample is associated with the connectivity of the embedded polyaniline molecules. The connectivity increases as the number of dipping cycle progresses. Meanwhile, the decrease in surface conductivity is attributed to the eroding of existing embedded structure at higher number of dipping cycle.

In vitro evaluation of the L-peptide modified magnetic lipid nanoparticles as targeted magnetic resonance imaging contrast agent for the nasopharyngeal cancer.

PubMed

Chen, Yung-Chu; Min, Chia-Na; Wu, Han-Chung; Lin, Chin-Tarng; Hsieh, Wen-Yuan

2013-11-01

The purpose of this study was to analyze the encapsulation of superparamagnetic iron oxide nanoparticles (SPION) by the lipid nanoparticle conjugated with the 12-mer peptides (RLLDTNRPLLPY, L-peptide), and the delivery of this complex into living cells. The lipid nanoparticles employed in this work were highly hydrophilic, stable, and contained poly(ethylene-glycol) for conjugation to the bioactive L-peptide. The particle sizes of two different magnetic lipid nanoparticles, L-peptide modified (LML) and non-L-peptide modified (ML), were both around 170 nm with a narrow range of size disparity. The transversal relaxivity, r2, for both LML and ML nanoparticles were found to be significantly higher than the longitudinal relaxivity r1 (r2/r1 > 20). The in vitro tumor cell targeting efficacy of the LML nanoparticles were evaluated and compared to the ML nanoparticles, upon observing cellular uptake of magnetic lipid nanoparticles by the nasopharyngeal carcinoma cells, which express cell surface specific protein for the L-peptide binding revealed. In the Prussian blue staining experiment, cells incubated with LML nanoparticles indicated much higher intracellular iron density than cells incubated with only the ML and SPION nanoparticles. In addition, the MTT assay showed the negligible cell cytotoxicity for LML, ML and SPION nanoparticles. The MR imaging studies demonstrate the better T2-weighted images for the LML-nanoparticle-loaded nasopharyngeal carcinoma cells than the ML- and SPION-loaded cells.

Photocatalytic performance of Ag doped SnO2 nanoparticles modified with curcumin

NASA Astrophysics Data System (ADS)

Vignesh, K.; Hariharan, R.; Rajarajan, M.; Suganthi, A.

2013-07-01

Visible light active Ag doped SnO2 nanoparticles modified with curcumin (Cur-Ag-SnO2) have been prepared by a combined precipitation and chemical impregnation route. The optical properties, phase structures and morphologies of the as-prepared nanoparticles were characterized using UV-visible diffuse reflectance spectra (UV-vis-DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The surface area was measured by Brunauer. Emmett. Teller (B.E.T) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag-SnO2 and Cur-Ag-SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Cur-Ag-SnO2 shows better photocatalytic activity than that of Ag-SnO2 and SnO2. The superior photocatalytic activity of Cur-Ag-SnO2 could be attributed to the effective electron-hole separation by surface modification. The effect of photocatalyst concentration, initial dye concentration and electron scavenger on the photocatalytic activity was examined in detail. Furthermore, the antifungal activity of the photocatalysts and the reusability of Cur-Ag-SnO2 were tested.

A comparative study for adsorption of lysozyme from aqueous samples onto Fe3O4 magnetic nanoparticles using different ionic liquids as modifier.

PubMed

Kamran, Sedigheh; Absalan, Ghodratollah; Asadi, Mozaffar

2015-12-01

In this paper, nanoparticles of Fe3O4 as well as their modified forms with different ionic liquids (IL-Fe3O4) were prepared and used for adsorption of lysozyme. The mean size and the surface morphology of the nanoparticles were characterized by TEM, XRD and FTIR techniques. Adsorption studies of lysozyme were performed under different experimental conditions in batch system on different modified magnetic nanoparticles such as, lysozyme concentration, pH of the solution, and contact time. Experimental results were obtained under the optimum operational conditions of pH 9.0 and a contact time of 10 min when initial protein concentrations of 0.05-2.0 mg mL(-1) were used. The isotherm evaluations revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The maximum obtained adsorption capacities were 370.4, 400.0 500.0 and 526.3 mg of lysozyme for adsorption onto Fe3O4 and modified magnetic nanoparticles by [C4MIM][Br], [C6MIM][Br] and [C8MIM][Br] per gram of adsorbent, respectively. The Langmuir adsorption constants were 0.004, 0.019, 0.024 and 0.012 L mg(-1) for adsorptions of lysozyme onto Fe3O4 and modified magnetic nanoparticles by [C4MIM][Br], [C6MIM][Br] and [C8MIM][Br], respectively. The adsorption capacity of lysozyme was found to be dependent on its chemical structure, pH of the solution, temperature and type of ionic liquid as modifier. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated. Furthermore, the thermodynamic parameters were calculated. Protein could desorb from IL-Fe3O4 nanoparticles by using NaCl solution at pH 9.5 and was reused.

[In vitro early detection of amyloid plaques in Alzheimer's disease by Pittsburgh compound B-modified magnetic nanoparticles].

PubMed

Zeng, J Q; Wu, J Q; Li, M H; Wang, P J

2017-11-07

Objective: To construct magnetic nanoparticles targeting β-amyloid (Aβ) plaques, the pathological biomarker of Alzheimer's disease (AD) and to study their binding capability in vitro . Methods: Superparamagnetic nanoparticles Mn(0.6)Zn(0.4)Fe(2)O(4) (MZF) were coated with amphiphilic star-block copolymeric micelles and modified with Aβ-specific probe Pittsburgh compound B (PiB) to construct a novel magnetic nanoparticle MZF-PiB, which specifically targeted amyloid plaques. Transmission electron microscope was used to study the morphological features of MZF-PiB. Superparamagnetism of MZF-PiB was assessed by its r(2) relaxation rate by using 3.0 T MRI scanner. Cytotoxic test was applied to determine biosafety of MZF-PiB nanoparticles in differentiated human neuroblastoma cells (SH-SY5Y) and Madin-Darby canine kidney (MDCK). In vitro binding tests were conducted via immunohistochemistry on 6-month old AD mice brain sections. Differences of cell viability between groups were compared with one-way analysis of variance. Results: MZF-PiB nanoparticles were successfully constructed. Transmission electron microscope images showed that the nanoparticles were about 100 nm in size. The r(2) relaxation rate was 163.11 mMS(-1). No differences were found in cell viability of SH-SY5Y and MDCK incubated with MZF-PiB suspension for 24 h or 48 h when compared with those of untreated cells ( F =2.336, 2.539, 0.293, 1.493, all P >0.05). In vitro binding tests indicated that the MZF-PiB were specifically bound to amyloid plaques. The smallest size of detected plaques was 27 μm. Conclusion: PiB-modified nanoparticles targeting Aβ are biologically safe and highly superparamagnetic, possessing the capability to detect amyloid plaques early in vitro and the potential for early diagnosis of AD.

Preparation of platinum modified titanium dioxide nanoparticles with the use of laser ablation in water.

PubMed

Siuzdak, K; Sawczak, M; Klein, M; Nowaczyk, G; Jurga, S; Cenian, A

2014-08-07

We report on the preparation method of nanocrystalline titanium dioxide modified with platinum by using nanosecond laser ablation in liquid (LAL). Titania in the form of anatase crystals has been prepared in a two-stage process. Initially, irradiation by laser beam of a titanium metal plate fixed in a glass container filled with deionized water was conducted. After that, the ablation process was continued, with the use of a platinum target placed in a freshly obtained titania colloid. In this work, characterization of the obtained nanoparticles, based on spectroscopic techniques--Raman, X-ray photoelectron and UV-vis reflectance spectroscopy--is given. High resolution transmission electron microscopy was used to describe particle morphology. On the basis of photocatalytic studies we observed the rate of degradation process of methylene blue (MB) (a model organic pollution) in the presence of Pt modified titania in comparison to pure TiO2--as a reference case. Physical and chemical mechanisms of the formation of platinum modified titania are also discussed here. Stable colloidal suspensions containing Pt modified titanium dioxide crystalline anatase particles show an almost perfect spherical shape with diameters ranging from 5 to 30 nm. The TiO2 nanoparticles decorated with platinum exhibit much higher (up to 30%) photocatalytic activity towards the degradation of MB under UV illumination than pure titania.

Electrochemical and in vitro neuronal recording characteristics of multi-electrode arrays surface-modified with electro-co-deposited gold-platinum nanoparticles.

PubMed

Kim, Yong Hee; Kim, Ah Young; Kim, Gook Hwa; Han, Young Hwan; Chung, Myung-Ae; Jung, Sang-Don

2016-02-01

In order to complement the high impedance electrical property of gold nanoparticles (Au NPs) we have performed electro-co-deposition of gold-platinum nanoparticles (Au-Pt NPs) onto the Au multi-electrode array (MEA) and modified the Au-Pt NPs surface with cell adhesive poly-D-lysine via thiol chemistry based covalent binding. The Au-Pt NPs were analyzed to have bimetallic nature not the mixture of Au NPs and Pt NPs by X-ray diffraction analysis and to have impedance value (4.0 × 10(4) Ω (at 1 kHz)) comparable to that of Pt NPs. The performance of Au-Pt NP-modified MEAs was also checked in relation to neuronal signal recording. The noise level in Au-Pt NP-modified MEAs was lower than in that of Au NP-modified MEA.

Study of Swift Heavy Ion Modified Conducting Polymer Composites for Application as Gas Sensor

PubMed Central

Srivastava, Alok; Singh, Virendra; Dhand, Chetna; Kaur, Manindar; Singh, Tejvir; Witte, Karin; Scherer, Ulrich W.

2006-01-01

A polyaniline-based conducting composite was prepared by oxidative polymerisation of aniline in a polyvinylchloride (PVC) matrix. The coherent free standing thin films of the composite were prepared by a solution casting method. The polyvinyl chloride-polyaniline composites exposed to 120 MeV ions of silicon with total ion fluence ranging from 1011 to 1013 ions/cm2, were observed to be more sensitive towards ammonia gas than the unirradiated composite. The response time of the irradiated composites was observed to be comparably shorter. We report for the first time the application of swift heavy ion modified insulating polymer conducting polymer (IPCP) composites for sensing of ammonia gas.

Advanced Synthesis of Conductive Polyaniline Using Laccase as Biocatalyst.

PubMed

de Salas, Felipe; Pardo, Isabel; Salavagione, Horacio J; Aza, Pablo; Amougi, Eleni; Vind, Jesper; Martínez, Angel T; Camarero, Susana

2016-01-01

Polyaniline is a conductive polymer with distinctive optical and electrical properties. Its enzymatic synthesis is an environmentally friendly alternative to the use of harsh oxidants and extremely acidic conditions. 7D5L, a high-redox potential laccase developed in our lab, is the biocatalyst of choice for the synthesis of green polyaniline (emeraldine salt) due to its superior ability to oxidize aniline and kinetic stability at the required polymerization conditions (pH 3 and presence of anionic surfactants) as compared with other fungal laccases. Doses as low as 7.6 nM of 7D5L catalyze the polymerization of 15 mM aniline (in 24 h, room temperature, 7% yield) in the presence of different anionic surfactants used as doping templates to provide linear and water-soluble polymers. Aniline polymerization was monitored by the increase of the polaron absorption band at 800 nm (typical for emeraldine salt). Best polymerization results were obtained with 5 mM sodium dodecylbenzenesulfonate (SDBS) as template. At fixed conditions (15 mM aniline and 5mM SDBS), polymerization rates obtained with 7D5L were 2.5-fold the rates obtained with commercial Trametes villosa laccase. Moreover, polyaniline yield was notably boosted to 75% by rising 7D5L amount to 0.15 μM, obtaining 1g of green polyaniline in 1L-reaction volume. The green polymer obtained with the selected system (7D5L/SDBS) holds excellent electrochemical and electro-conductive properties displayed in water-dispersible nanofibers, which is advantageous for the nanomaterial to be readily cast into uniform films for different applications.

Advanced Synthesis of Conductive Polyaniline Using Laccase as Biocatalyst

PubMed Central

de Salas, Felipe; Pardo, Isabel; Salavagione, Horacio J.; Aza, Pablo; Amougi, Eleni; Vind, Jesper; Martínez, Angel T.; Camarero, Susana

2016-01-01

Polyaniline is a conductive polymer with distinctive optical and electrical properties. Its enzymatic synthesis is an environmentally friendly alternative to the use of harsh oxidants and extremely acidic conditions. 7D5L, a high-redox potential laccase developed in our lab, is the biocatalyst of choice for the synthesis of green polyaniline (emeraldine salt) due to its superior ability to oxidize aniline and kinetic stability at the required polymerization conditions (pH 3 and presence of anionic surfactants) as compared with other fungal laccases. Doses as low as 7.6 nM of 7D5L catalyze the polymerization of 15 mM aniline (in 24 h, room temperature, 7% yield) in the presence of different anionic surfactants used as doping templates to provide linear and water-soluble polymers. Aniline polymerization was monitored by the increase of the polaron absorption band at 800 nm (typical for emeraldine salt). Best polymerization results were obtained with 5 mM sodium dodecylbenzenesulfonate (SDBS) as template. At fixed conditions (15 mM aniline and 5mM SDBS), polymerization rates obtained with 7D5L were 2.5-fold the rates obtained with commercial Trametes villosa laccase. Moreover, polyaniline yield was notably boosted to 75% by rising 7D5L amount to 0.15 μM, obtaining 1g of green polyaniline in 1L-reaction volume. The green polymer obtained with the selected system (7D5L/SDBS) holds excellent electrochemical and electro-conductive properties displayed in water-dispersible nanofibers, which is advantageous for the nanomaterial to be readily cast into uniform films for different applications. PMID:27741301

3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes

PubMed Central

Bishop, Gregory W.; Satterwhite, Jennifer E.; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M.; Chen, Eric; Rusling, James F.

2015-01-01

A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 × 800 µm2 square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 µL min−1. PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 µM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods. PMID:25901660

Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process.

PubMed

Sun, Qunhui; Bi, Wu; Fuller, Thomas F; Ding, Yong; Deng, Yulin

2009-06-17

In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4-aminothiophenol (4-ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm(-2) , was synthesized. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modified kinetics of enzymes interacting with nanoparticles

NASA Astrophysics Data System (ADS)

Díaz, Sebastián. A.; Breger, Joyce C.; Malanoski, Anthony; Claussen, Jonathan C.; Walper, Scott A.; Ancona, Mario G.; Brown, Carl W.; Stewart, Michael H.; Oh, Eunkeu; Susumu, Kimihiro; Medintz, Igor L.

2015-08-01

Enzymes are important players in multiple applications, be it bioremediation, biosynthesis, or as reporters. The business of catalysis and inhibition of enzymes is a multibillion dollar industry and understanding the kinetics of commercial enzymes can have a large impact on how these systems are optimized. Recent advances in nanotechnology have opened up the field of nanoparticle (NP) and enzyme conjugates and two principal architectures for NP conjugate systems have been developed. In the first example the enzyme is bound to the NP in a persistent manner, here we find that key factors such as directed enzyme conjugation allow for enhanced kinetics. Through controlled comparative experiments we begin to tease out specific mechanisms that may account for the enhancement. The second system is based on dynamic interactions of the enzymes with the NP. The enzyme substrate is bound to the NP and the enzyme is free in solution. Here again we find that there are many variables , such as substrate positioning and NP selection, that modify the kinetics.

Enantiomeric separations of chiral pharmaceuticals using chirally modified tetrahexahedral Au nanoparticles

NASA Astrophysics Data System (ADS)

Shukla, N.; Yang, D.; Gellman, A. J.

2016-06-01

Tetrahexahedral (THH, 24-sided) Au nanoparticles modified with D- or L-cysteine (Cys) have been used as enantioselective separators of the chiral pharmaceutical propranolol (PLL) in solution phase. Polarimetry has been used to measure the rotation of linearly polarized light by solutions containing mixtures of PLL and Cys/THH-Au NPs with varying enantiomeric excesses of each. Polarimetry yields clear evidence of enantiospecific adsorption of PLL onto the Cys/THH-Au NPs. This extends prior work using propylene oxide as a test chiral probe, by using the crystalline THH Au NPs with well-defined facets to separate a real pharmaceutical. This work suggests that chiral nanoparticles, coupled with a density separation method such as centrifugation, could be used for enantiomeric purification of real pharmaceuticals. A simple robust model developed earlier has also been used to extract the enantiospecific equilibrium constants for R- and S-PLL adsorption onto the D- and L-Cys/THH-Au NPs.

Doxorubicin-loaded glycyrrhetinic acid modified recombinant human serum albumin nanoparticles for targeting liver tumor chemotherapy.

PubMed

Qi, Wen-Wen; Yu, Hai-Yan; Guo, Hui; Lou, Jun; Wang, Zhi-Ming; Liu, Peng; Sapin-Minet, Anne; Maincent, Philippe; Hong, Xue-Chuan; Hu, Xian-Ming; Xiao, Yu-Ling

2015-03-02

Due to overexpression of glycyrrhetinic acid (GA) receptor in liver cancer cells, glycyrrhetinic acid modified recombinant human serum albumin (rHSA) nanoparticles for targeting liver tumor cells may result in increased therapeutic efficacy and decreased adverse effects of cancer therapy. In this study, doxorubicin (DOX) loaded and glycyrrhetinic acid modified recombinant human serum albumin nanoparticles (DOX/GA-rHSA NPs) were prepared for targeting therapy for liver cancer. GA was covalently coupled to recombinant human serum albumin nanoparticles, which could efficiently deliver DOX into liver cancer cells. The resultant GA-rHSA NPs exhibited uniform spherical shape and high stability in plasma with fixed negative charge (∼-25 mV) and a size about 170 nm. DOX was loaded into GA-rHSA NPs with a maximal encapsulation efficiency of 75.8%. Moreover, the targeted NPs (DOX/GA-rHSA NPs) showed increased cytotoxic activity in liver tumor cells compared to the nontargeted NPs (DOX/rHSA NPs, DOX loaded recombinant human serum albumin nanoparticles without GA conjugating). The targeted NPs exhibited higher cellular uptake in a GA receptor-positive liver cancer cell line than nontargeted NPs as measured by both flow cytometry and confocal laser scanning microscopy. Biodistribution experiments showed that DOX/GA-rHSA NPs exhibited a much higher level of tumor accumulation than nontargeted NPs at 1 h after injection in hepatoma-bearing Balb/c mice. Therefore, the DOX/GA-rHSA NPs could be considered as an efficient nanoplatform for targeting drug delivery system for liver cancer.

Small Angle Neutron Scattering (SANS) Characterization of Electrically Conducting Polyaniline Nanofiber/Polyimide Nanocomposites

DTIC Science & Technology

2011-10-25

range, neither the D-B nor the IPL model could be used to characterize the size and shape of all PANI-0.5-CSA (polyaniline camphor sulfonic acid doped...be used to characterize the size and shape of all PANI-0.5-CSA (polyaniline camphor sulfonic acid doped polymer)/polyimide blend systems. At 1 and 2

Enhanced permeability of blood-brain barrier and targeting function of brain via borneol-modified chemically solid lipid nanoparticle.

PubMed

Song, Hui; Wei, Man; Zhang, Nan; Li, He; Tan, Xiaochuan; Zhang, Yujia; Zheng, Wensheng

2018-01-01

The incidence of central nervous system disease has increased in recent years. However, the transportation of drug is restricted by the blood-brain barrier, contributing to the poor therapeutic effect in the brain. Therefore, the development of a new brain-targeting drug delivery system has become the hotspot of pharmacy. Borneol, a simple bicyclic monoterpene extracted from Dryobalanops aromatica , can direct drugs to the upper body parts according to the theory of traditional Chinese medicine. Dioleoyl phosphoethanolamine (DOPE) was chemically modified by borneol as one of the lipid materials of solid lipid nanoparticle (SLN) in the present study. The borneol-modified chemically solid lipid nanoparticle (BO-SLN/CM), borneol-modified physically solid lipid nanoparticle (BO-SLN/PM), and SLN have similar diameter (of about 87 nm) and morphological characteristics. However, BO-SLN/CM has a lower cytotoxicity, higher cell uptake, and better blood-brain barrier permeability compared with BO-SLN/PM and SLN. BO-SLN/CM has a remarkable targeting function to the brain, while BO-SLN/ PM and SLNs are concentrated at the lung. The present study provides an excellent drug delivery carrier, BO-SLN/CM, having the application potential of targeting to the brain and permeating to the blood-brain barrier.

Dewetting of polymer thin films on modified curved surfaces: preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates.

PubMed

Liu, Chih-Ting; Tsai, Chia-Chan; Chu, Chien-Wei; Chi, Mu-Huan; Chung, Pei-Yun; Chen, Jiun-Tai

2018-04-18

We study the dewetting behaviors of poly(methyl methacrylate) (PMMA) thin films coated in the cylindrical nanopores of anodic aluminum oxide (AAO) templates by thermal annealing. Self-assembled monolayers (SAMs) of n-octadecyltrichlorosilane (ODTS) are introduced to modify the pore surfaces of the AAO templates to induce the dewetting process. By using scanning electron microscopy (SEM), the dewetting-induced morphology transformation from the PMMA thin films to PMMA nanoparticles with asymmetric shapes can be observed. The sizes of the PMMA nanoparticles can be controlled by the original PMMA solution concentrations. The dewetting phenomena on the modified nanopores are explained by taking into account the excess intermolecular interaction free energy (ΔG). This work opens a new possibility for creating polymer nanoparticles with asymmetric shapes in confined geometries.

Synthesis and characterization of polyaniline coated gold nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuber, Siti Nurzulaiha Mohd; Kamarun, Dzaraini; Zaki, Hamizah

2015-08-28

Considerable attention has been drawn during the last two decades to prepare nanocomposites consists of conducting polymer and noble metal due to their potential ability to generate a new class of material with novel optical, chemical, electronic or mechanical properties for various applications. In this work, an attempt has been made to synthesize nanocomposite of polyaniline (PANI) coated with gold nanoparticles (AuNPs) chemically with various types of surfactants such as polyvinylpyrrolidone (PVP), and sodium dodecyl sulphate (SDS) which act as stabilizing agents to help in stabilization of the PANI/Gold nanocomposites system. The synthesized nanocomposites were characterized by UV-Visible, field emissionmore » scanning electron microscope (FESEM) and particle size analyzer (PSA). The formation of finger like structure can be seen in the FESEM images when the AuNPs were incorporated into the polymer matrix. The EDX data showed that 18.66% and 12.67% of AuNPs atoms were present in the composite system thus proved the incorporation of AuNPs into the polymer matrix. A small red shift of the absorption peak in the UV-Vis of both PANI/AuNPs composites system may be due to the incorporation of AuNPs in the PANI matrix.« less

Tannic acid-modified silver nanoparticles for wound healing: the importance of size

PubMed Central

Orlowski, Piotr; Zmigrodzka, Magdalena; Tomaszewska, Emilia; Ranoszek-Soliwoda, Katarzyna; Czupryn, Monika; Antos-Bielska, Malgorzata; Szemraj, Janusz; Celichowski, Grzegorz; Grobelny, Jaroslaw

2018-01-01

Introduction Silver nanoparticles (AgNPs) have been shown to promote wound healing and to exhibit antimicrobial properties against a broad range of bacteria. In our previous study, we prepared tannic acid (TA)-modified AgNPs showing a good toxicological profile and immunomodulatory properties useful for potential dermal applications. Methods In this study, in vitro scratch assay, antimicrobial tests, modified lymph node assay as well as a mouse splint wound model were used to access the wound healing potential of TA-modified and unmodified AgNPs. Results TA-modified but not unmodified AgNPs exhibited effective antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and stimulated migration of keratinocytes in vitro. The tests using the mouse splint wound model showed that TA-modified 33 and 46 nm AgNPs promoted better wound closure, epithelialization, angiogenesis and formation of the granulation tissue. Additionally, AgNPs elicited expression of VEGF-α, PDGF-β and TGF-β1 cytokines involved in wound healing more efficiently in comparison to control and TA-treated wounds. However, both the lymph node assay and the wound model showed that TA-modified AgNPs sized 13 nm can elicit strong inflammatory response not only during wound healing but also when applied to the damaged skin. Conclusion TA-modified AgNPs sized >26 nm promote wound healing better than TA-modified or unmodified AgNPs. These findings suggest that TA-modified AgNPs sized >26 nm may have a promising application in wound management. PMID:29497293

Redox-Switchable Surface Wrinkling on Polyaniline Film.

PubMed

Xie, Jixun; Zong, Chuanyong; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Yang, Xiu; Lu, Conghua

2016-04-01

Here the redox-driven switch between the wrinkled and dewrinkled states on poly-aniline (PANI) film is reported. This switch is derived from the reversible transition in different intrinsic redox states of polyaniline (e.g., between emeraldine salt (ES) and leucoemeraldine base (LEB) or between ES and pernigraniline base (PB)) that are involved in the redox reaction, coupled with the corresponding volume expansion/shrinkage. Interestingly, the as-wrinkled ES film becomes deswollen and dewrinkled when reduced to the LEB state or oxidized to the PB state. Conversely, oxidation of the LEB film or reduction of the PB film into the swollen ES film leads to the reoccurrence of surface wrinkling. Furthermore, the reducibility of the dewrinkled LEB film and the oxidizability of the dewrinkled PB film are well utilized respectively to yield various wrinkled PANI-based composite films. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanowires of silver-polyaniline nanocomposite synthesized via in situ polymerization and its novel functionality as an antibacterial agent.

PubMed

Tamboli, Mohaseen S; Kulkarni, Milind V; Patil, Rajendra H; Gade, Wasudev N; Navale, Shalaka C; Kale, Bharat B

2012-04-01

Silver-polyaniline (Ag-PANI) nanocomposite was synthesized by in situ polymerization method using ammonium persulfate (APS) as an oxidizing agent in the presence of dodecylbenzene sulfonic acid (DBSA) and silver nitrate (AgNO(3)). The as synthesized Ag-PANI nanocomposite was characterized by using different analytical techniques such as UV-visible (UV-vis) and Fourier transform Infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). UV-visible spectra of the synthesized nanocomposite showed a sharp peak at ~420 nm corresponding to the surface plasmon resonance (SPR) of the silver nanoparticles (AgNPs) embedded in the polymer matrix which is overlapped by the polaronic peak of polyaniline appearing at that wavelength. Nanowires of Ag-PANI nanocomposite with diameter 50-70 nm were observed in FE-SEM and TEM. TGA has indicated an enhanced thermal stability of nanocomposite as compared to that of pure polymer. The Ag-PANI nanocomposite has shown an antibacterial activity against model organisms, a gram positive Bacillus subtilis NCIM 6633 in Mueller-Hinton (MH) medium, which is hitherto unattempted. The Ag-PANI nanocomposite with monodispersed AgNPs is considered to have potential applications in sensors, catalysis, batteries and electronic devices. Copyright © 2011 Elsevier B.V. All rights reserved.

High permittivity polyaniline-barium titanate nanocomposites with excellent electromagnetic interference shielding response

NASA Astrophysics Data System (ADS)

Saini, Parveen; Arora, Manju; Gupta, Govind; Gupta, Bipin Kumar; Singh, Vidya Nand; Choudhary, Veena

2013-05-01

Organic conductive polymers are at the forefront of materials science research because of their diverse applications built around their interesting and unique properties. This work reports for the first time a correlation between the structural, electrical, and electromagnetic properties of polyaniline (PANI)-tetragonal BaTiO3 (TBT) nanocomposites prepared by in-situ emulsion polymerization. XRD studies and HRTEM micrographs of these nanocomposites clearly revealed the incorporation of TBT nanoparticles in the conducting PANI matrix. EPR and XPS measurements reveal that increase in loading level of BaTiO3 results in a reduction of the doping level of PANI. The Ku-Band (12.4-18 GHz) network analysis of these composites shows exceptional microwave shielding response with absorption dominated total shielding effectiveness (SET) value of -71.5 dB (blockage of more than 99.99999% of incident radiation) which is the highest value reported in the literature. Such a high attenuation level, which critically depends on the fraction of BaTiO3 is attributed to optimized dielectric and electrical attributes. This demonstrates the possibility of using these materials in stealth technology and for making futuristic radar absorbing materials (RAMs).Organic conductive polymers are at the forefront of materials science research because of their diverse applications built around their interesting and unique properties. This work reports for the first time a correlation between the structural, electrical, and electromagnetic properties of polyaniline (PANI)-tetragonal BaTiO3 (TBT) nanocomposites prepared by in-situ emulsion polymerization. XRD studies and HRTEM micrographs of these nanocomposites clearly revealed the incorporation of TBT nanoparticles in the conducting PANI matrix. EPR and XPS measurements reveal that increase in loading level of BaTiO3 results in a reduction of the doping level of PANI. The Ku-Band (12.4-18 GHz) network analysis of these composites shows exceptional

Comparison of magnetic carboxymethyl chitosan nanoparticles and cation exchange resin for the efficient purification of lysine-tagged small ubiquitin-like modifier protease.

PubMed

Li, Junhua; Zhang, Yang; Shen, Fei; Yang, Yanjun

2012-10-15

A fusion tag that can be purified by the cheap ion-exchanger based on the ionic binding force may provide a cost-effective scheme over other affinity fusion tags. Small ubiquitin-like modifier (SUMO) protease derived from Saccharomyces cerevisiae was fused with a poly lysine tag containing 10 lysine residues at its C-terminus and then expressed in Escherichia coli. The ionic binding force provided by the ploy lysine tag allowed the selective recovery of the small ubiquitin-like modifier protease from recombinant E. coli cell extracts. A preliminary comparative study of the adsorption and elution of poly lysine tagged SUMO protease on Amberlite Cobalamion and magnetite carboxymethyl chitosan nanoparticles was performed. Amberlite Cobalamion and magnetite nanoparticles had the similar elution profile due to the common functional groups - carboxyl groups. The maximum dynamic adsorption capacity of Amberlite Cobalamion and magnetite nanoparticles reached 36.8 and 211.4 mg/g, respectively. The lysine-tagged protease can be simply purified by magnetite nanoparticles from cell extracts with higher purity than that by Amberlite Cobalamion. The superparamagnetic nanoparticles possess the advantages of highly specific, fast and excellent binding of a larger amount of lysine tagged SUMO modifier protease, and it is also easier to separate from the crude biological process liquors compared with the conventional separation techniques of polycationic amino acids fusion proteins. Copyright © 2012 Elsevier B.V. All rights reserved.

Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density

NASA Astrophysics Data System (ADS)

Cheng, Qian; Tang, Jie; Shinya, Norio; Qin, Lu-Chang

2013-11-01

Graphene and single-walled carbon nanotube (CNT) composites are explored as the electrodes for supercapacitors by coating polyaniline (PANI) nano-cones onto the graphene/CNT composite to obtain graphene/CNT-PANI composite electrode. The graphene/CNT-PANI electrode is assembled with a graphene/CNT electrode into an asymmetric pseudocapacitor and a highest energy density of 188 Wh kg-1 and maximum power density of 200 kW kg-1 are achieved. The structure and morphology of the graphene/CNT composite and the PANI nano-cone coatings are characterized by both scanning electron microscopy and transmission electron microscopy. The excellent performance of the assembled supercapacitors is also discussed and it is attributed to (i) effective utilization of the large surface area of the three-dimensional network structure of graphene-based composite, (ii) the presence of CNT in the composite preventing graphene from re-stacking, and (ii) uniform and vertically aligned PANI coating on graphene offering increased electrical conductivity.

An Electrochemical DNA Sensing System Using Modified Nanoparticle Probes for Detecting Methicillin-Resistant Staphylococcus aureus.

PubMed

Sakamoto, Hiroaki; Amano, Yoshihisa; Satomura, Takenori; Suye, Shin-Ichiro

2017-01-01

We have developed a novel, highly sensitive, biosensing system for detecting methicillin-resistant Staphylococcus aureus (MRSA). The system employs gold nanoparticles (AuNPs), magnetic nanoparticles (mNPs), and an electrochemical detection method. We have designed and synthesized ferrocene- and single-stranded DNA-conjugated nanoparticles that hybridize to MRSA DNA. Hybridized complexes are easily separated by taking advantage of mNPs. A current response could be obtained through the oxidation of ferrocene on the AuNP surface when a constant potential of +250 mV vs. Ag/AgCl is applied. The enzymatic reaction of L-proline dehydrogenase provides high signal amplification. This sensing system, using a nanoparticle-modified probe, has the ability to detect 10 pM of genomic DNA from MRSA without amplification by the polymerase chain reaction. Current responses are linearly related to the amount of genomic DNA in the range of 10-166 pM. Selectivity is confirmed by demonstrating that this sensing system could distinguish MRSA from Staphylococcus aureus (SA) DNA.

Surface-modified solid lipid nanoparticles for oral delivery of docetaxel: enhanced intestinal absorption and lymphatic uptake

PubMed Central

Cho, Hyun-Jong; Park, Jin Woo; Yoon, In-Soo; Kim, Dae-Duk

2014-01-01

Docetaxel is a potent anticancer drug, but development of an oral formulation has been hindered mainly due to its poor oral bioavailability. In this study, solid lipid nanoparticles (SLNs) surface-modified by Tween 80 or D-alpha-tocopheryl poly(ethylene glycol 1000) succinate (TPGS 1000) were prepared and evaluated in terms of their feasibility as oral delivery systems for docetaxel. Tween 80-emulsified and TPGS 1000-emulsified tristearin-based lipidic nanoparticles were prepared by a solvent-diffusion method, and their particle size distribution, zeta potential, drug loading, and particle morphology were characterized. An in vitro release study showed a sustained-release profile of docetaxel from the SLNs compared with an intravenous docetaxel formulation (Taxotere®). Tween 80-emulsified SLNs showed enhanced intestinal absorption, lymphatic uptake, and relative oral bioavailability of docetaxel compared with Taxotere in rats. These results may be attributable to the absorption-enhancing effects of the tristearin nanoparticle. Moreover, compared with Tween 80-emulsified SLNs, the intestinal absorption and relative oral bioavailability of docetaxel in rats were further improved in TPGS 1000-emulsified SLNs, probably due to better inhibition of drug efflux by TPGS 1000, along with intestinal lymphatic uptake. Taken together, it is worth noting that these surface-modified SLNs may serve as efficient oral delivery systems for docetaxel. PMID:24531717

The feasibility of using magnetic nanoparticles modified as gene vector.

PubMed

Chen, D; Tang, Q; Xue, W; Wang, X

2010-06-01

To evaluate the feasibility of using magnetic nanoparticles (MNPs) as gene vector and the effect of magnetic field on efficiency of transfection. Magnetic nanoparticles were prepared by controlling some chemical reaction parameters through a partially reduction precipitation method with ferric chloride aqueous solution as precursor material. The surface of particles was modified by polyethyleneimine (PEI) agents. The appearance, the size distribution, structure and phase constitute of MNPs were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD); the potential of absorbing DNA of MNPs was analysed by electrophoresis. Transfection was determined by delivering reporter gene, PGL2-control encoding luciferase, to different cell lines using MNPs-PLL as vector. The effect of magnetic field on the efficiency of transfection was determined using Nd-Fe-B permanent magnet. Foreign gene could be delivered to various cell lines by MNPs-PLL and expressed with high efficiency but the transfection efficiency and time course varied in the different cell lines studied. Magnetic field could enhance the efficiency of transfection by 5-10 fold. MNPs- PLL can be used as a novel non-viral gene vector in vitro, which offers a basis for gene delivery in vivo.

Nanoengineering of 2D tin sulfide nanoflake arrays incorporated on polyaniline nanofibers with boosted capacitive behavior

NASA Astrophysics Data System (ADS)

Wang, Huanhuan; Chao, DongLiang; Liu, Jilei; Lin, Jianyi; Shen, Ze Xiang

2018-07-01

Nanoscale engineering plays an important role in designing novel electrode architecture and boosting energy storage in supercapacitors. Herein, we demonstrate the fabrication of freestanding tin sulfide based supercapacitor electrode using facile nucleation substrate control, i.e. polyaniline network. This is the first time that tin sulfide based material is fabricated as a binder-free electrode for supercapacitors. The first combination of tin sulfide and polyaniline also evokes synergistic effect to enhance the performance as the polyaniline nanofibers facilitate the growth of tin sulfide flakes in nanosize which is further proved helpful for improving the capacity and stability of the electrode. The as-obtained electrode of tin sulfide nanoflake arrays incorporated on polyaniline nanofibers (365 F g‑1 at 10 mV s‑1) exhibits superior electrochemical performance compared with micro-scaled tin sulfide (32 F g‑1 at 10 mV s‑1). The significantly improved pseudocapacitive and diffusive contributions of polyaniline nanofibers incorporated electrode are identified by quantitative kinetics analysis due to greatly decreased particle size and introduced mesopores, nanoclusters, and exposed edges. Profited from effective nanostructure engineering, a Na+ intercalation mechanism is also pointed out in boosting the electrochemical performance.

Uptake of Retinoic Acid-Modified PMMA Nanoparticles in LX-2 and Liver Tissue by Raman Imaging and Intravital Microscopy.

PubMed

Yildirim, Turgay; Matthäus, Christian; Press, Adrian T; Schubert, Stephanie; Bauer, Michael; Popp, Jürgen; Schubert, Ulrich S

2017-10-01

A primary amino-functionalized methyl methacrylate-based statistical copolymer is covalently coupled with retinoic acid (RA) and a fluorescent dye (DY590) in order to investigate the feasibility of the RA containing polymeric nanoparticles for Raman imaging studies and to study the possible selectivity of RA for hepatic stellate cells via intravital microscopy. Cationic nanoparticles are prepared by utilizing the nanoprecipitation method using modified polymers. Raman studies show that RA functional nanoparticles can be detectable in all tested cells without any need of additional label. Moreover, intravital microscopy indicates that DY590 is eliminated through the hepatobiliary route but not if used as covalently attached tracing molecule for nanoparticles. However, it is a suitable probe for sensitive detection of polymeric nanoparticles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile route to covalently-jointed graphene/polyaniline composite and it's enhanced electrochemical performances for supercapacitors

NASA Astrophysics Data System (ADS)

Qiu, Hanxun; Han, Xuebin; Qiu, Feilong; Yang, Junhe

2016-07-01

A polyaniline/graphene composite with covalently-bond is synthesized by a novel approach. In this way, graphene oxide is functionalized firstly by introducing amine groups onto the surface with the reduction of graphene oxide in the process and then served as the anchor sites for the growth of polyaniline (PANI) via in-situ polymerization. The composite material is characterized by electron microscopy, the resonant Raman spectra, X-ray diffraction, transform infrared spectroscopy and X-ray photoelectron spectroscopy. The electrochemical properties of the composite are measured by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charging/discharging. With the functionalization process, the graphene/polyaniline composite electrode exhibits remarkably enhanced electrochemical performance with specific capacitance of 489 F g-1 at 0.5 A g-1, which is superior to those of its individual components. The outstanding electrochemical performance of the hybrid can be attributed to its covalently synergistic effect between graphene and polyaniline, suggesting promising potentials for supercapacitors.

Design of an inhalable dry powder formulation of DOTAP-modified PLGA nanoparticles loaded with siRNA.

PubMed

Jensen, Ditte Krohn; Jensen, Linda Boye; Koocheki, Saeid; Bengtson, Lasse; Cun, Dongmei; Nielsen, Hanne Mørck; Foged, Camilla

2012-01-10

Matrix systems based on biocompatible and biodegradable polymers like the United States Food and Drug Administration (FDA)-approved polymer poly(DL-lactide-co-glycolide acid) (PLGA) are promising for the delivery of small interfering RNA (siRNA) due to favorable safety profiles, sustained release properties and improved colloidal stability, as compared to polyplexes. The purpose of this study was to design a dry powder formulation based on cationic lipid-modified PLGA nanoparticles intended for treatment of severe lung diseases by pulmonary delivery of siRNA. The cationic lipid dioleoyltrimethylammoniumpropane (DOTAP) was incorporated into the PLGA matrix to potentiate the gene silencing efficiency. The gene knock-down level in vitro was positively correlated to the weight ratio of DOTAP in the particles, and 73% silencing was achieved in the presence of 10% (v/v) serum at 25% (w/w) DOTAP. Optimal properties were found for nanoparticles modified with 15% (w/w) DOTAP, which reduced the gene expression with 54%. This formulation was spray-dried with mannitol into nanocomposite microparticles of an aerodynamic size appropriate for lung deposition. The spray-drying process did not affect the physicochemical properties of the readily re-dispersible nanoparticles, and most importantly, the in vitro gene silencing activity was preserved during spray-drying. The siRNA content in the powder was similar to the theoretical loading and the siRNA was intact, suggesting that the siRNA is preserved during the spray-drying process. Finally, X-ray powder diffraction analysis demonstrated that mannitol remained in a crystalline state upon spray-drying with PLGA nanoparticles suggesting that the sugar excipient might exert its stabilizing effect by sterical inhibition of the interactions between adjacent nanoparticles. This study demonstrates that spray-drying is an excellent technique for engineering dry powder formulations of siRNA nanoparticles, which might enable the local

Voltammetric sensor for buzepide methiodide determination based on TiO2 nanoparticle-modified carbon paste electrode.

PubMed

Kalanur, Shankara S; Seetharamappa, Jaldappagari; Prashanth, S N

2010-07-01

In this work, we have prepared nano-material modified carbon paste electrode (CPE) for the sensing of an antidepressant, buzepide methiodide (BZP) by incorporating TiO2 nanoparticles in carbon paste matrix. Electrochemical studies indicated that the TiO2 nanoparticles efficiently increased the electron transfer kinetics between drug and the electrode. Compared with the nonmodified CPE, the TiO2-modified CPE greatly enhances the oxidation signal of BZP with negative shift in peak potential. Based on this, we have proposed a sensitive, rapid and convenient electrochemical method for the determination of BZP. Under the optimized conditions, the oxidation peak current of BZP is found to be proportional to its concentration in the range of 5 x 10(-8) to 5 x 10(-5)M with a detection limit of 8.2 x 10(-9)M. Finally, this sensing method was successfully applied for the determination of BZP in human blood serum and urine samples with good recoveries. 2010 Elsevier B.V. All rights reserved.

An electrochemical genosensor for Salmonella typhi on gold nanoparticles-mercaptosilane modified screen printed electrode.

PubMed

Das, Ritu; Sharma, Mukesh K; Rao, Vepa K; Bhattacharya, B K; Garg, Iti; Venkatesh, V; Upadhyay, Sanjay

2014-10-20

In this work, we fabricated a system of integrated self-assembled layer of organosilane 3-mercaptopropyltrimethoxy silane (MPTS) on the screen printed electrode (SPE) and electrochemically deposited gold nanoparticle for Salmonella typhi detection employing Vi gene as a molecular marker. Thiolated DNA probe was immobilized on a gold nanoparticle (AuNP) modified SPE for DNA hybridization assay using methylene blue as redox (electroactive) hybridization indicator, and signal was monitored by differential pulse voltammetry (DPV) method. The modified SPE was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) method. The DNA biosensor showed excellent performances with high sensitivity and good selectivity. The current response was linear with the target sequence concentrations ranging from 1.0 × 10(-11) to 0.5 × 10(-8)M and the detection limit was found to be 50 (± 2.1)pM. The DNA biosensor showed good discrimination ability to the one-base, two-base and three-base mismatched sequences. The fabricated genosensor could also be regenerated easily and reused for three to four times for further hybridization studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Graphite felt modified with bismuth nanoparticles as negative electrode in a vanadium redox flow battery.

PubMed

Suárez, David J; González, Zoraida; Blanco, Clara; Granda, Marcos; Menéndez, Rosa; Santamaría, Ricardo

2014-03-01

A graphite felt decorated with bismuth nanoparticles was studied as negative electrode in a vanadium redox flow battery (VRFB). The results confirm the excellent electrochemical performance of the bismuth modified electrode in terms of the reversibility of the V(3+) /V(2+) redox reactions and its long-term cycling performance. Moreover a mechanism that explains the role that Bi nanoparticles play in the redox reactions in this negative half-cell is proposed. Bi nanoparticles favor the formation of BiHx , an intermediate that reduces V(3+) to V(2+) and, therefore, inhibits the competitive irreversible reaction of hydrogen formation (responsible for the commonly observed loss of Coulombic efficiency of VRFBs). Thus, the total charge consumed during the cathodic sweep in this electrode is used to reduce V(3+) to V(2+) , resulting in a highly reversible and efficient process. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrophobically modified glycol chitosan nanoparticles-encapsulated camptothecin enhance the drug stability and tumor targeting in cancer therapy.

PubMed

Min, Kyung Hyun; Park, Kyeongsoon; Kim, Yoo-Shin; Bae, Sang Mun; Lee, Seulki; Jo, Hyung Gon; Park, Rang-Woon; Kim, In-San; Jeong, Seo Young; Kim, Kwangmeyung; Kwon, Ick Chan

2008-05-08

To prepare a water-insoluble camptothecin (CPT) delivery carrier, hydrophobically modified glycol chitosan (HGC) nanoparticles were constructed by chemical conjugation of hydrophobic 5beta-cholanic acid moieties to the hydrophilic glycol chitosan backbone. Insoluble anticancer drug, CPT, was easily encapsulated into HGC nanoparticles by a dialysis method and the drug loading efficiency was above 80%. CPT-encapsulated HGC (CPT-HGC) nanoparticles formed nano-sized self-aggregates in aqueous media (280-330 nm in diameter) and showed sustained release of CPT for 1 week. Also, HGC nanoparticles effectively protected the active lactone ring of CPT from the hydrolysis under physiological condition, due to the encapsulation of CPT into the hydrophobic cores in the HGC nanoparticles. The CPT-HGC nanoparticles exhibited significant antitumor effects and high tumor targeting ability towards MDA-MB231 human breast cancer xenografts subcutaneously implanted in nude mice. Tumor growth was significantly inhibited after i.v. injection of CPT-HGC nanoparticles at doses of 10 mg/kg and 30 mg/kg, compared to free CPT at dose of 30 mg/kg. The significant antitumor efficacy of CPT-HGC nanoparticles was attributed to the ability of the nanoparticles to show both prolonged blood circulation and high accumulation in tumors, as confirmed by near infrared (NIR) fluorescence imaging systems. Thus, the delivery of CPT to tumor tissues at a high concentration, with the assistance of HGC nanoparticles, exerted a potent therapeutic effect. These results reveal the promising potential of HGC nanoparticles-encapsulated CPT as a stable and effective drug delivery system in cancer therapy.

Fabrication and characterization of polyaniline/PVA humidity microsensors.

PubMed

Yang, Ming-Zhi; Dai, Ching-Liang; Lin, Wei-Yi

2011-01-01

This study presents the fabrication and characterization of a humidity microsensor that consists of interdigitated electrodes and a sensitive film. The area of the humidity microsensor is about 2 mm(2). The sensitive film is polyaniline doping polyvinyl alcohol (PVA) that is prepared by the sol-gel method, and the film has nanofiber and porous structures that help increase the sensing reaction. The commercial 0.35 μm Complimentary Metal Oxide Semiconductor (CMOS) process is used to fabricate the humidity microsensor. The sensor needs a post-CMOS process to etch the sacrificial layer and to coat the sensitive film on the interdigitated electrodes. The sensor produces a change in resistance as the polyaniline/PVA film absorbs or desorbs vapor. Experimental results show that the sensitivity of the humidity sensor is about 12.6 kΩ/%RH at 25 °C.

Nanostructured metal-polyaniline composites and applications thereof

DOEpatents

Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

2012-10-02

Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

A Genetically Modified Tobacco Mosaic Virus that can Produce Gold Nanoparticles from a Metal Salt Precursor

PubMed Central

Love, Andrew J.; Makarov, Valentine V.; Sinitsyna, Olga V.; Shaw, Jane; Yaminsky, Igor V.; Kalinina, Natalia O.; Taliansky, Michael E.

2015-01-01

We genetically modified tobacco mosaic virus (TMV) to surface display a characterized peptide with potent metal ion binding and reducing capacity (MBP TMV), and demonstrate that unlike wild type TMV, this construct can lead to the formation of discrete 10–40 nm gold nanoparticles when mixed with 3 mM potassium tetrachloroaurate. Using a variety of analytical physicochemical approaches it was found that these nanoparticles were crystalline in nature and stable. Given that the MBP TMV can produce metal nanomaterials in the absence of chemical reductants, it may have utility in the green production of metal nanomaterials. PMID:26617624

Electrical conductivity and morphology of electrochemical synthesized polyaniline/CuO nano composites

NASA Astrophysics Data System (ADS)

Ashokkumar, S. P.; Yesappa, L.; Vijeth, H.; Niranjana, M.; Devendrappa, H.

2018-05-01

Polyaniline (PANI) and Polyaniline/CuO nanocomposite have been synthesized by using electrochemical deposition method. The composite was characterized using Fourier transform infra-red spectroscopy (FT-IR) to confirm the chemical interaction changes, micro structural morphology was done by Field Emission Scanning Electronic Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM). The dielectric constant and AC conductivity are found to increases with increase in temperature range (303 to 393K), these results shows enhancement in electrical conductivity due to effect of nanocomposite.

Fe3O4 nanoparticles modified by CD-containing star polymer for MRI and drug delivery.

PubMed

Cha, Ruitao; Li, Juanjuan; Liu, Yang; Zhang, Yifan; Xie, Qian; Zhang, Mingming

2017-10-01

Fe 3 O 4 nanoparticles with ultrasmall sizes show good T 1 or T 1 +T 2 contrast abilities, and have attracted considerable interest in the field of magnetic resonance imaging (MRI) contrast agents. For effective biomedical applications, the colloidal stability and biocompatibility of the Fe 3 O 4 nanoparticles need to be improved without reducing MRI relaxivity. In this paper, star polymers were used as coating materials to modify Fe 3 O 4 nanoparticles in view of their dense molecular architecture with moderate flexibility. The star polymer was composed of a β-cyclodextrin (β-CD) core and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) arms. Meanwhile, reduced glutathione (GSH), as a model drug, was also associated with the star polymer. Thus, a new platform for simultaneous diagnosis and treatment was achieved. Compared to the Fe 3 O 4 nanoparticles coated with linear polymers, the Fe 3 O 4 nanoparticles coated with star polymers (Fe 3 O 4 @GCP) possessed higher GSH association capacity and better stability in serum-containing solution. GSH could be released from Fe 3 O 4 @GCP nanoparticles in response to pH value of the solution. Since the sulfhydryl group on GSH is able to combine free radicals, Fe 3 O 4 @GCP nanoparticles exhibited less cytotoxicity compared to the Fe 3 O 4 nanoparticles without including GSH. Furthermore, the nanoparticles could also serve as good T 1 MRI contrast agent, and the MRI relaxivity of Fe 3 O 4 @GCP nanoparticles did not decrease after coated with the star polymer. These results indicate that the precisely designed Fe 3 O 4 @GCP nanoparticles could be used as a versatile promising theranostic nano-platform. Copyright © 2017 Elsevier B.V. All rights reserved.

Mesoporous Silica Nanoparticle Delivery of Chemically Modified siRNA Against TWIST1 Leads to Reduced Tumor Burden

PubMed Central

Finlay, James; Roberts, Cai M.; Dong, Juyao; Zink, Jeffrey I.; Tamanoi, Fuyuhiko; Glackin, Carlotta A.

2015-01-01

Growth and progression of solid tumors depends on the integration of multiple pro-growth and survival signals, including the induction of angiogenesis. TWIST1 is a transcription factor whose reactivation in tumors leads to epithelial to mesenchymal transition (EMT), including increased cancer cell stemness, survival, and invasiveness. Additionally, TWIST1 drives angiogenesis via activation of IL-8 and CCL2, independent of VEGF signaling. In this work, results suggest that chemically modified siRNA against TWIST1 reverses EMT both in vitro and in vivo. siRNA delivery with a polyethyleneimine-coated mesoporous silica nanoparticle (MSN) led to reduction of TWIST1 target genes and migratory potential in vitro. In mice bearing xenograft tumors, weekly intravenous injections of the siRNA-nanoparticle complexes resulted in decreased tumor burden together with a loss of CCL2 suggesting a possible anti-angiogenic response. Therapeutic use of TWIST1 siRNA delivered via MSNs has the potential to inhibit tumor growth and progression in many solid tumor types. Chemically modified siRNA against TWIST1 was complexed to cation-coated mesoporous silica nanoparticles and tested in vitro and in vivo. In cell culture experiments, siRNA reduced expression of TWIST1 and its target genes, and reduced cell migration. In mice, injections of the siRNA-nanoparticle complex led to reduced tumor weight. Data suggest that diminished tumor burden was the result of reduced CCL2 expression and angiogenesis following TWIST1 knockdown. PMID:26115637

Work Function and Conductivity Change in Polyaniline.

NASA Astrophysics Data System (ADS)

Chinn, Douglas Alan

1995-01-01

The purpose of this study was to elucidate some basic material properties of the conducting polymer polyaniline. Because of the intractable nature of the polymer, methods to make thin films were developed. The polymer was dissolved in formic acid and cast onto silicon substrates that had four metal leads in a parallel configuration. It was discovered that a cast film could be used as a substrate for the subsequent growth of additional film by electrochemical techniques. The polymer will spontaneously change oxidation states both in air and in solution if oxidized or reduced electrochemically. The change in oxidation states is seen as a changing open cell potential in solution and a change in work function and resistance in air. UV-visible and infrared spectroscopy were used to characterize the polymer during relaxation. The work function decreases from both the oxidized and reduced states, but resistance increases from the reduced state and decreases from the oxidized state in air. A two-phase model which has ordered conducting regions and disordered insulating regions has been used to describe the relaxation phenomena. The relaxation is caused by rearrangement within the film of dopant acid and water, allowing the film to develop ordered regions. It has been determined that chemical polyaniline and electrochemical polyaniline are nearly identical chemically, with the main differences being morphological. The relaxation phenomena can be used to make chemical sensors. As the film relaxes, electrons become available. The electrons reduce metallic ions, which interact with a detectant gas in a gas stream above the film. In films containing Hg_2Cl_2 work function decreases and resistance decreases when in contact with hydrogen cyanide in a dry nitrogen stream.

Modified bamboo rayon-copper nanoparticle composites as antibacterial textiles.

PubMed

Teli, M D; Sheikh, Javed

2013-10-01

In the current study the bamboo rayon fabric grafted with acrylamide was utilized as a backbone to immobilize copper nanoprticles. The grafted bamboo rayon was first treated with CuSO4 followed by chemical reduction. The modified product was characterized using FTIR, TGA and SEM. The characteristic color developed after reduction was measured spectrophotometrically. The grafted bamboo rayon with Cu nanoparticles was then evaluated for antibacterial activity against both gram positive and gram negative bacteria and the durability of their antibacterial activity after washing. The product showed antibacterial activity against both types of bacterias which was found to be durable till 50 washes. The material can be claimed as suitable candidate for medical textile applications to prevent cross-infections. Copyright © 2013 Elsevier B.V. All rights reserved.

Surface modified carbon nanoparticle papers and applications on polymer composites

NASA Astrophysics Data System (ADS)

Ouyang, Xilian

Free-standing paper like materials are usually employed as protective layers, chemical filters, components of electrical batteries or supercapacitors, adhesive layers, and electronic or optoelectric components. Free-standing papers made from carbon nanoparticles have drawn increased interest because they have a variety of superior chemical and physical characteristics, such as light weight, high intrinsic mechanical properties, and extraordinary high electrical conductivity. Nanopapers fabricated from 1- D shape carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are promising reinforcing materials for polymer composites, because the highly porous CNF and CNT nanopapers (porosity ˜80% and ˜70% respectively) can be impregnated with matrix polymers. In the first part of this work, polyaniline (PANI) was used to functionalize the surface of CNFs, and the resultant carbon nanopapers presented impressive mechanical strength and electrical conductivity that it could be used in the in-mold coating (IMC)/ injection molding process to achieve high electromagnetic interference (EMI) shielding effectiveness. Aniline modified (AF) CNT nanopapers were used as a 3D network in gas separation membranes. The resultant composite membranes demonstrated better and stable CO2 permeance and CO 2/H2 selectivity in a high temperature (107°C) and high pressure (15-30 atm) gas separation process, not achievable by conventional polymer membranes. In the second part, we demonstrated that 2-D graphene (GP) or graphene oxide (GO) nanosheets could be tightly packed into a film which was impermeable to most gases and liquids. GP or GO nanopapers could be coated on polymer composites. In order to achieve well-dispersed single-layer graphene in aqueous medium, we developed a facile approach to synthesize functional GP bearing benzenesulfonic acid groups which allow the preparation of nanopapers by water based assembly. With the optimized processing conditions, our best GP nanopapers could reach

Physicochemical properties of protein-modified silver nanoparticles in seawater

NASA Astrophysics Data System (ADS)

Zhong, Hangyue

2013-10-01

This study investigated the physicochemical properties of silver nanoparticles stabilized with casein protein in seawater. UV?vis spectrometry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied to measure the stability of silver nanoparticles in seawater samples. The obtained results show an increased aggregation tendency of silver nanoparticles in seawater, which could be attributed its relatively high cation concentration that could neutralize the negatively charges adsorbed on the surface of silver nanoparticles and reduce the electrostatic repulsion forces between nanoparticles. Similarly, due to the surface charge screening process, the zeta potential of silver nanoparticles in seawater decreased. This observation further supported the aggregation behavior of silver nanoparticles. This study also investigated the dissolution of silver nanoparticles in seawater. Result shows that the silver nanoparticle dissolution in DI water is lower than in seawater, which is attributed to the high Cl? concentration present in seawater. As Cl? can react with silver and form soluble AgCl complex, dissolution of silver nanoparticles was enhanced. Finally, this study demonstrated that silver nanoparticles are destabilized in seawater condition. These results may be helpful in understanding the environmental risk of discharged silver nanoparticles in seawater conditions.

Nanoparticle formation in a low pressure argon/aniline RF plasma

NASA Astrophysics Data System (ADS)

Pattyn, C.; Kovacevic, E.; Hussain, S.; Dias, A.; Lecas, T.; Berndt, J.

2018-01-01

The formation of nanoparticles in low temperature plasmas is of high importance for different fields: from astrophysics to microelectronics. The plasma based synthesis of nanoparticles is a complex multi-scale process that involves a great variety of different species and comprises timescales ranging from milliseconds to several minutes. This contribution focuses on the synthesis of nanoparticles in a low temperature, low pressure capacitively coupled plasma containing mixtures of argon and aniline. Aniline is commonly used for the production of polyaniline, a material that belongs to the family of conductive polymers, which has attracted increasing interest in the last few years due to the large number of potential applications. The nanoparticles which are formed in the plasma volume and levitate there due to the collection of negative charges are investigated in this contribution by means of in-situ FTIR spectroscopy. In addition, the plasma is analyzed by means of plasma (ion) mass spectroscopy. The experiments reveal the possibility to synthesize nanoparticles both in continuous wave and in pulsed discharges. The formation of particles in the plasma volume can be suppressed by pulsing the plasma in a specific frequency range. The in-situ FTIR analysis also reveals the influence of the argon plasma on the characteristics of the nanoparticles.

Bi-enzyme L-arginine-selective amperometric biosensor based on ammonium-sensing polyaniline-modified electrode.

PubMed

Stasyuk, Nataliya; Smutok, Oleh; Gayda, Galina; Vus, Bohdan; Koval'chuk, Yevgen; Gonchar, Mykhailo

2012-01-01

A novel L-arginine-selective amperometric bi-enzyme biosensor based on recombinant human arginase I isolated from the gene-engineered strain of methylotrophic yeast Hansenula polymorpha and commercial urease is described. The biosensing layer was placed onto a polyaniline-Nafion composite platinum electrode and covered with a calcium alginate gel. The developed sensor revealed a good selectivity to L-arginine. The sensitivity of the biosensor was 110 ± 1.3 nA/(mM mm(2)) with the apparent Michaelis-Menten constant (K(M)(app)) derived from an L-arginine (L-Arg) calibration curve of 1.27 ± 0.29 mM. A linear concentration range was observed from 0.07 to 0.6mM, a limit of detection being 0.038 mM and a response time - 10s. The developed biosensor demonstrated good storage stability. A laboratory prototype of the proposed amperometric biosensor was applied to the samples of three commercial pharmaceuticals ("Tivortin", "Cytrarginine", "Aminoplazmal 10% E") for L-Arg testing. The obtained L-Arg-content values correlated well with those declared by producers. Copyright © 2012 Elsevier B.V. All rights reserved.

Development of Modified Titanium Nitride Nanoparticles as Potential Contrast Material for Photoacoustic Imaging

DTIC Science & Technology

2014-05-10

based on modified fullerenes , carbon nanotubes and gold nanoparticles (including nanocages and nanorods) were very recently reported.4 Nevertheless, this...ratios of 1:1.6 and 1:16, in order to form an onion- like core-shell structure, containing TiN core and shells of TPP (inner shell) and chitosan (outer...These results nicely correlate with the cells viability results and the formation of the ROS is most likely the cause of the cells death (Figure 24

Novel one-pot facile technique for preparing nanoparticles modified with hydrophilic polymers on the surface via block polymer-assisted emulsification/evaporation process.

PubMed

Kanakubo, Yurie; Ito, Fuminori; Murakami, Yoshihiko

2010-06-15

In this paper, we describe the novel facile technique for preparing surface-modified nanoparticles via newly developed amphiphilic block polymer-assisted emulsification/evaporation process. The effects of both organic solvents (the dispersed phase) and stabilizer in the external continuous phase on the stability of o/w emulsion was firstly investigated to clarify the optimal conditions for stable emulsification/evaporation processes. We found that the organic solvent mixture having a density adjusted to be 1.00 g/cm(3) gave the highly stable o/w emulsion. Under the optimal conditions, the relatively monodisperse poly(ethylene glycol) (PEG)-modified poly(lactide-co-glycolide) (PLGA) nanoparticle was obtained and characterized. The introduction of PEG to the particle surface was suggested by the fact that the diameter and zeta potential of the particle increased as the amount of added block polymer increased. The facile method presented in this paper can be a universal tool for modifying the surface of nanoparticles, even though reactive groups are not present on the surface. Copyright 2010 Elsevier B.V. All rights reserved.

Carbon-polyaniline nanocomposites as supercapacitor materials

NASA Astrophysics Data System (ADS)

Sathish Kumar, M.; Yamini Yasoda, K.; Batabyal, Sudip Kumar; Kothurkar, Nikhil K.

2018-04-01

Polyaniline-based nanocomposites containing carbon nanotubes (CNT), reduced graphene oxide (rGO) and mixture of CNTs and rGO were synthesized. UV-visible spectroscopy and FT-IR spectroscopy confirmed the presence of polyaniline (PANi) and carbon nanomaterials. Scanning electron microscopy revealed that the neat PANi had a granular morphology, which can lead to increased electrical resistance to high interfacial resistance between domains of PANi. Cyclic voltammetry of PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO showed that in general, specific capacitance reduces with increasing scan rate within the range (10–100 mV s‑1). Also the specific capacitance values at any given scan rate within the above range, for PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO were found to be in increasing order. The specific capacitance of the PANi/CNT/rGO nanocomposite as measured by galvanostatic charge-discharge measurements, was found to be 312.5 F g‑1. The introduction of the carbon nanomaterials (CNTs, rGO) in PANi in general leads to improved specific capacitance, while the addition of CNTs and rGO together leads to synergistic improvement in the specific capacitance, owing to a combination of factors.

Superhydrophobic Ag nanostructures on polyaniline membranes with strong SERS enhancement.

PubMed

Liu, Weiyu; Miao, Peng; Xiong, Lu; Du, Yunchen; Han, Xijiang; Xu, Ping

2014-11-07

We demonstrate here a facile fabrication of n-dodecyl mercaptan-modified superhydrophobic Ag nanostructures on polyaniline membranes for molecular detection based on SERS technique, which combines the superhydrophobic condensation effect and the high enhancement factor. It is calculated that the as-fabricated superhydrophobic substrate can exhibit a 21-fold stronger molecular condensation, and thus further amplifies the SERS signal to achieve more sensitive detection. The detection limit of the target molecule, methylene blue (MB), on this superhydrophobic substrate can be 1 order of magnitude higher than that on the hydrophilic substrate. With high reproducibility, the feasibility of using this SERS-active superhydrophobic substrate for quantitative molecular detection is explored. A partial least squares (PLS) model was established for the quantification of MB by SERS, with correlation coefficient R(2) = 95.1% and root-mean-squared error of prediction (RMSEP) = 0.226. We believe this superhydrophobic SERS substrate can be widely used in trace analysis due to its facile fabrication, high signal reproducibility and promising SERS performance.

Separation of pharmacologically active nitrogen-containing compounds on silica gels modified with 6,10-ionene, dextran sulfate, and gold nanoparticles

NASA Astrophysics Data System (ADS)

Ioutsi, A. N.; Shapovalova, E. N.; Ioutsi, V. A.; Mazhuga, A. G.; Shpigun, O. A.

2017-12-01

New stationary phases for HPLC are obtained via layer-by-layer deposition of polyelectrolytes and studied: (1) silica gel modified layer-by-layer with 6,10-ionene and dextran sulfate (Sorbent 1); (2) silica gel twice subjected to the above modification (Sorbent 2); and (3) silica gel modified with 6,10-ionene, gold nanoparticles, and dextran sulfate (Sorbent 3). The effect the content of the organic solvent in the mobile phase and the concentration and pH of the buffer solution have on the chromatographic behavior of several pharmacologically active nitrogen-containing compounds is studied. The sorbents are stable during the process and allow the effective separation of beta-blockers, calcium channel blockers, alpha-agonists, and antihistamines. A mixture of caffeine, nadolol, tetrahydrozoline, pindolol, orphenadrine, doxylamine, carbinoxamine, and chlorphenamine is separated in 6.5 min on the silica gel modified with 6,10-ionene, gold nanoparticles, and dextran sulfate.

Optimized synthesis of glycyrrhetinic acid-modified chitosan 5-fluorouracil nanoparticles and their characteristics

PubMed Central

Cheng, Mingrong; Chen, Houxiang; Wang, Yong; Xu, Hongzhi; He, Bing; Han, Jiang; Zhang, Zhiping

2014-01-01

The nanoparticle drug delivery system, which uses natural or synthetic polymeric material as a carrier to deliver drugs to targeted tissues, has a broad prospect for clinical application for its targeting, slow-release, and biodegradable properties. Here, we used chitosan (CTS) and hepatoma cell-specific binding molecule glycyrrhetinic acid to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by infrared (IR) spectra and hydrogen-1 nuclear magnetic resonance. The GA-CTS/5-fluorouracil (5-FU) nanoparticles were synthesized by combining GA-CTS and 5-FU and conjugating 5-FU onto the GA-CTS nanomaterial. The central composite design was performed to optimize the preparation process as CTS:tripolyphosphate sodium (TPP) weight ratio =5:1, 5-FU:CTS weight ratio =1:1, TPP concentration =0.05% (w/v), and cross-link time =50 minutes. GA-CTS/5-FU nanoparticles had a mean particle size of 193.7 nm, a polydispersity index of 0.003, a zeta potential of +27.4 mV, and a drug loading of 1.56%. The GA-CTS/5-FU nanoparticle had a protective effect on the drug against plasma degrading enzyme, and provided a sustained release system comprising three distinct phases of quick, steady, and slow release. Our study showed that the peak time, half-life time, mean residence time and area under the curve of GA-CTS/5-FU were longer or more than those of the 5-FU group, but the maximum concentration (Cmax) was lower. We demonstrated that the nanoparticles accumulated in the liver and have significantly inhibited tumor growth in an orthotropic liver cancer mouse model. PMID:24493926

Development of antibody-modified chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier as a strategy for inhibiting HIV replication in astrocytes.

PubMed

Gu, Jijin; Al-Bayati, Karam; Ho, Emmanuel A

2017-08-01

RNA interference (RNAi)-mediated gene silencing offers a novel treatment and prevention strategy for human immunodeficiency virus (HIV) infection. HIV was found to infect and replicate in human brain cells and can cause neuroinfections and neurological deterioration. We designed dual-antibody-modified chitosan/small interfering RNA (siRNA) nanoparticles to deliver siRNA across the blood-brain barrier (BBB) targeting HIV-infected brain astrocytes as a strategy for inhibiting HIV replication. We hypothesized that transferrin antibody and bradykinin B2 antibody could specifically bind to the transferrin receptor (TfR) and bradykinin B2 receptor (B2R), respectively, and deliver siRNA across the BBB into astrocytes as potential targeting ligands. In this study, chitosan nanoparticles (CS-NPs) were prepared by a complex coacervation method in the presence of siRNA, and antibody was chemically conjugated to the nanoparticles. The antibody-modified chitosan nanoparticles (Ab-CS-NPs) were spherical in shape, with an average particle size of 235.7 ± 10.2 nm and a zeta potential of 22.88 ± 1.78 mV. The therapeutic potential of the nanoparticles was evaluated based on their cellular uptake and gene silencing efficiency. Cellular accumulation and gene silencing efficiency of Ab-CS-NPs in astrocytes were significantly improved compared to non-modified CS-NPs and single-antibody-modified CS-NPs. These results suggest that the combination of anti-Tf antibody and anti-B2 antibody significantly increased the knockdown effect of siRNA-loaded nanoparticles. Thus, antibody-mediated dual-targeting nanoparticles are an efficient and promising delivery strategy for inhibiting HIV replication in astrocytes. Graphical abstract Graphic representation of dual-antibody-conjugated chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier (BBB) for inhibiting HIV replication in astrocytes. a Nanoparticle delivery to the BBB and penetration. b Tf

Water treatment with exceptional virus inactivation using activated carbon modified with silver (Ag) and copper oxide (CuO) nanoparticles.

PubMed

Shimabuku, Quelen Letícia; Arakawa, Flávia Sayuri; Fernandes Silva, Marcela; Ferri Coldebella, Priscila; Ueda-Nakamura, Tânia; Fagundes-Klen, Márcia Regina; Bergamasco, Rosangela

2017-08-01

Continuous flow experiments (450 mL min -1 ) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy. The antiviral activity of the produced porous media was evaluated by passing suspensions of T4 bacteriophage (∼10 5  UFP/mL) through filters. The filtered water was analyzed for the presence of the bacteriophage and the release of silver and copper oxide. The porous media containing silver and copper oxide nanoparticles showed high inactivation capacity, even reaching reductions higher than 3 log. GAC6 (GAC/Ag0.5%Cu1.0%) was effective in the bacteriophage inactivation, reaching 5.53 log reduction. The levels of silver and copper released in filtered water were below the recommended limits (100 ppb for silver and 1000 ppb for copper) in drinking water. From this study, it is possible to conclude that activated carbon modified with silver and copper oxide nanoparticles can be used as a filter for virus removal in the treatment of drinking water.

Temperature dependent thermoelectric property of reduced graphene oxide-polyaniline composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitra, Mousumi, E-mail: mousumimitrabesu@gmail.com; Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com; Kargupta, Kajari, E-mail: karguptakajari2010@gmail.com

2016-05-06

A composite material of reduced graphene oxide (rG) nanosheets with polyaniline (PANI) protonated by 5-sulfosalicylic acid has been synthesized via in situ oxidative polymerization method. The morphological and spectral characterizations have been done using FESEM and XRD measurements. The thermoelectric (TE) properties of the reduced graphene oxide-polyaniline composite (rG-P) has been studied in the temperature range from 300-400 K. The electrical conductivity and the Seebeck coefficient of rG-P is higher than the of pure PANI, while the thermal conductivity of the composite still keeps much low value ensuing an increase in the dimensionless figure of merit (ZT) in the wholemore » temperature range.« less

Influence of Poly(vinylpyrrolidone) concentration on properties of silver nanoparticles manufactured by modified thermal treatment method

PubMed Central

Saion, Elias; Gharibshahi, Elham; Shaari, Abdul Halim; Matori, Khamirul Amin

2017-01-01

Very narrow and pure silver nanoparticles were synthesized by modified thermal treatment method via oxygen and nitrogen flow in succession. The structural and optical properties of the calcined silver nanoparticles at 600°C with diverse Poly(vinylpyrrolidone) concentrations varied from 2% to 4% were studied by means of different techniques. Fourier transform infrared spectroscopy was used to monitor the production of pure Ag nanoparticles at a given Poly(vinylpyrrolidone) concentration. The X-ray powder diffraction spectra are evidence for the transformation of the amorphous sample at 30°C to the cubic crystalline nanostructures at the calcination temperatures for all Poly(vinylpyrrolidone) concentrations. The transmission electron microscopy images showed the creation of spherical silver nanoparticles with the average particle size decreased by increasing Poly(vinylpyrrolidone) concentrations from 4.61 nm at 2% to 2.49 nm at 4% Poly(vinylpyrrolidone). The optical properties were investigated by means of UV–vis absorption spectrophotometer, which showed an increase in the conduction band of Ag nanoparticles with increasing Poly(vinylpyrrolidone) concentrations from 2.83 eV at 2% Poly(vinylpyrrolidone) to 2.94 eV at 4% Poly(vinylpyrrolidone) due to decreasing particle size. This was due to less attraction between conduction electrons and metal ions for smaller particle size corresponding to fewer atoms that made up the metal nanoparticles. PMID:29045414

Carbon nanostructured films modified by metal nanoparticles supported on filtering membranes for electroanalysis.

PubMed

Paramo, Erica; Palmero, Susana; Heras, Aranzazu; Colina, Alvaro

2018-02-01

A novel methodology to prepare sensors based on carbon nanostructures electrodes modified by metal nanoparticles is proposed. As a proof of concept, a novel bismuth nanoparticle/carbon nanofiber (Bi-NPs/CNF) electrode and a carbon nanotube (CNT)/gold nanoparticle (Au-NPs) have been developed. Bi-NPs/CNF films were prepared by 1) filtering a dispersion of CNFs on a polytetrafluorethylene (PTFE) filter, and 2) filtering a dispersion of Bi-NPs chemically synthesized through this CNF/PTFE film. Next the electrode is prepared by sticking the Bi-NPs/CNF/PTFE film on a PET substrate. In this work, Bi-NPs/CNF ratio was optimized using a Cd 2+ solution as a probe sample. The Cd anodic stripping peak intensity, registered by differential pulse anodic stripping voltammetry (DPASV), is selected as target signal. The voltammograms registered for Cd stripping with this Bi-NPs/CNF/PTFE electrode showed well-defined and highly reproducible electrochemical. The optimized Bi-NPs/CNF electrode exhibits a Cd 2+ detection limit of 53.57 ppb. To demonstrate the utility and versatility of this methodology, single walled carbon nanotubes (SWCNTs) and gold nanoparticles (Au-NPs) were selected to prepare a completely different electrode. Thus, the new Au-NPs/SWCNT/PTFE electrode was tested with a multiresponse technique. In this case, UV/Vis absorption spectroelectrochemistry experiments were carried out for studying dopamine, demonstrating the good performance of the Au-NPs/SWCNT electrode developed. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of low-pressure glow-discharge-pulsed plasma polymerization on properties of polyaniline thin films

NASA Astrophysics Data System (ADS)

Jatratkar, Aviraj A.; Yadav, Jyotiprakash B.; Deshmukh, R. R.; Barshilia, Harish C.; Puri, Vijaya; Puri, R. K.

2016-12-01

This study reports on polyaniline thin films deposited on a glass substrate using a low-pressure glow-discharge-pulsed plasma polymerization method. The polyaniline thin film obtained by pulsed plasma polymerization has been successfully demonstrated as an optical waveguide with a transmission loss of 3.93 dB cm-1, and has the potential to be employed in integrated optics. An attempt has been made to investigate the effect of plasma OFF-time on the structural, optical as well as surface properties of polyaniline thin film. The plasma ON-time has been kept constant and the plasma OFF-time has been varied throughout the work. The plasma OFF-time strongly influenced the properties of the polyaniline thin film, and a nanostructured and compact surface was revealed in the morphological studies. The plasma OFF-time was found to enhance film thickness, roughness, refractive index and optical transmission loss, whereas it reduced the optical band gap of the polyaniline thin films. Retention in the aromatic structure was confirmed by FTIR results. Optical studies revealed a π-π* electronic transition at about 317 nm as well as the formation of a branched structure. As compared with continuous wave plasma, pulsed plasma polymerization shows better properties. Pulsed plasma polymerization reduced the roughness of the film from 1.2 nm to 0.42 nm and the optical transmission loss from 6.56 dB cm-1 to 3.39 dB cm-1.

Highly anisotropic conductivity of tablets pressed from polyaniline-montmorillonite nanocomposite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokarský, Jonáš, E-mail: jonas.tokarsky@vsb.cz; IT4Innovations Centre of Excellence, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba; Kulhánková, Lenka

2016-03-15

Highlights: • Montmorillonite (MMT) can be intercalated with polyaniline (PANI) chains. • Tablets pressed from PANI/MMT exhibit high anisotropy in electrical conductivity. • Pressure 28MPa is sufficient to reach the anisotropy. • Tablets pressed from pure PANI also exhibit anisotropy in electrical conductivity. - Abstract: Polyaniline-montmorillonite nanocomposite was prepared from anilinium sulfate (precursor) and ammonium peroxodisulfate (oxidizing agent) using simple one-step method. The resulting nanocomposite obtained in powder form has been pressed into tablets using various compression pressures (28–400 MPa). Electrical conductivities of tablets in two perpendicular directions, i.e. direction parallel with the main surface of tablet (σ=) and inmore » orthogonal direction (σ⊥), and corresponding anisotropy factors (i.e., the ratio σ=/σ⊥) have been studied in dependence on compression pressure used during the preparation. Polyaniline-montmorillonite nanocomposite was characterized using X-ray diffraction analysis, raman spectroscopy, transmission electron microscopy, thermogravimetric analysis and molecular modeling which led to the understanding of the internal structure. Measurement of hardness performed on pressed tablets has been also involved. Taking into account the highest value of anisotropy factor reached (σ=/σ⊥ = 490), present study shows a chance to design conductors with nearly two-dimensional conductivity.« less

Modifying mesoporous silica nanoparticles to avoid the metabolic deactivation of 6-mercaptopurine and methotrexate in combinatorial chemotherapy

NASA Astrophysics Data System (ADS)

Wang, Wenjing; Fang, Chenjie; Wang, Xiaozhu; Chen, Yuxi; Wang, Yaonan; Feng, Wei; Yan, Chunhua; Zhao, Ming; Peng, Shiqi

2013-06-01

Mesoporous silica nanoparticles with amino and thiol groups (MSNSN) were prepared and covalently modified with methotrexate and 6-mercaptopurine to form 6-MP-MSNSN-MTX. In the presence of DTT, 6-MP-MSNSN-MTX gradually releases 6-MP. In rat plasma, 6-MP-MSNSN-MTX effectively inhibits the metabolic deactivation of 6-MP and MTX. 6-MP-MSNSN-MTX could be an agent for long-acting chemotherapy.Mesoporous silica nanoparticles with amino and thiol groups (MSNSN) were prepared and covalently modified with methotrexate and 6-mercaptopurine to form 6-MP-MSNSN-MTX. In the presence of DTT, 6-MP-MSNSN-MTX gradually releases 6-MP. In rat plasma, 6-MP-MSNSN-MTX effectively inhibits the metabolic deactivation of 6-MP and MTX. 6-MP-MSNSN-MTX could be an agent for long-acting chemotherapy. Electronic supplementary information (ESI) available: Experimental details of the synthesis and in vitro and in vivo assays. See DOI: 10.1039/c3nr00227f

A single-step aerosol process for in-situ surface modification of nanoparticles: Preparation of stable aqueous nanoparticle suspensions.

PubMed

Sapra, Mahak; Pawar, Amol Ashok; Venkataraman, Chandra

2016-02-15

Surface modification of nanoparticles during aerosol or gas-phase synthesis, followed by direct transfer into liquid media can be used to produce stable water-dispersed nanoparticle suspensions. This work investigates a single-step, aerosol process for in-situ surface-modification of nanoparticles. Previous studies have used a two-step sublimation-condensation mechanism following droplet drying, for surface modification, while the present process uses a liquid precursor containing two solutes, a matrix lipid and a surface modifying agent. A precursor solution in chloroform, of stearic acid lipid, with 4 %w/w of surface-active, physiological molecules [1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol)-sodium salt (DPPG) or 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol) 2000]-ammonium salt (DPPE-PEG)] was processed in an aerosol reactor at a low gas temperatures. The surface modified nanoparticles were characterized for morphology, surface composition and suspension properties. Spherical, surface-modified lipid nanoparticles with median mobility diameters in the range of 105-150nm and unimodal size distributions were obtained. Fourier transform infra-red spectroscopy (FTIR) measurements confirmed the presence of surface-active molecules on external surfaces of modified lipid nanoparticles. Surface modified nanoparticles exhibited improved suspension stability, compared to that of pure lipid nanoparticles for a period of 30days. Lowest aggregation was observed in DPPE-PEG modified nanoparticles from combined electrostatic and steric effects. The study provides a single-step aerosol method for in-situ surface modification of nanoparticles, using minimal amounts of surface active agents, to make stable, aqueous nanoparticle suspensions. Copyright © 2015 Elsevier Inc. All rights reserved.

D-Glucose as a modifying agent in gelatin/collagen matrix and reservoir nanoparticles for Calendula officinalis delivery.

PubMed

Lam, P-L; Kok, S H-L; Bian, Z-X; Lam, K-H; Tang, J C-O; Lee, K K-H; Gambari, R; Chui, C-H

2014-05-01

Gelatin/Collagen-based matrix and reservoir nanoparticles require crosslinkers to stabilize the formed nanosuspensions, considering that physical instability is the main challenge of nanoparticulate systems. The use of crosslinkers improves the physical integrity of nanoformulations under the-host environment. Aldehyde-based fixatives, such as formaldehyde and glutaraldehyde, have been widely applied to the crosslinking process of polymeric nanoparticles. However, their potential toxicity towards human beings has been demonstrated in many previous studies. In order to tackle this problem, D-glucose was used during nanoparticle formation to stabilize the gelatin/collagen-based matrix wall and reservoir wall for the deliveries of Calendula officinalis powder and oil, respectively. In addition, therapeutic selectivity between malignant and normal cells could be observed. The C. officinalis powder loaded nanoparticles significantly strengthened the anti-cancer effect towards human breast adenocarcinoma MCF7 cells and human hepatoma SKHep1 cells when compared with the free powder. On the contrary, the nanoparticles did not show significant cytotoxicity towards normal esophageal epithelial NE3 cells and human skin keratinocyte HaCaT cells. On the basis of these evidences, D-glucose modified gelatin/collagen matrix nanoparticles containing C. officinalis powder might be proposed as a safer alternative vehicle for anti-cancer treatments. Copyright © 2014 Elsevier B.V. All rights reserved.

A Functional Iron Oxide Nanoparticles Modified with PLA-PEG-DG as Tumor-Targeted MRI Contrast Agent.

PubMed

Xiong, Fei; Hu, Ke; Yu, Haoli; Zhou, Lijun; Song, Lina; Zhang, Yu; Shan, Xiuhong; Liu, Jianping; Gu, Ning

2017-08-01

Tumor targeting could greatly promote the performance of magnetic nanomaterials as MRI (Magnetic Resonance Imaging) agent for tumor diagnosis. Herein, we reported a novel magnetic nanoparticle modified with PLA (poly lactic acid)-PEG (polyethylene glycol)-DG (D-glucosamine) as Tumor-targeted MRI Contrast Agent. In this work, we took use of the D-glucose passive targeting on tumor cells, combining it on PLA-PEG through amide reaction, and then wrapped the PLA-PEG-DG up to the Fe 3 O 4 @OA NPs. The stability and anti phagocytosis of Fe 3 O 4 @OA@PLA-PEG-DG was tested in vitro; the MRI efficiency and toxicity was also detected in vivo. These functional magnetic nanoparticles demonstrated good biocompatibility and stability both in vitro and in vivo. Cell experiments showed that Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles exist good anti phagocytosis and high targetability. In vivo MRI images showed that the contrast effect of Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles prevailed over the commercial non tumor-targeting magnetic nanomaterials MRI agent at a relatively low dose. The DG can validly enhance the tumor-targetting effect of Fe 3 O 4 @OA@PLA-PEG nanoparticle. Maybe MRI agents with DG can hold promise as tumor-targetting development in the future.

Polyaniline-based optical ammonia detector

DOEpatents

Duan, Yixiang; Jin, Zhe; Su, Yongxuan

2002-01-01

Electronic absorption spectroscopy of a polyaniline film deposited on a polyethylene surface by chemical oxidation of aniline monomer at room temperature was used to quantitatively detect ammonia gas. The present optical ammonia gas detector was found to have a response time of less than 15 s, a regeneration time of less than 2 min. at room temperature, and a detection limit of 1 ppm (v/v) for ammonia, with a linear dynamic range from 180 ppm to 18,000 ppm.

Electrochemical detection of Hg (II) ions using EDTA-PANI/SWNTs nanocomposite modified SS electrode

NASA Astrophysics Data System (ADS)

Deshmukh, M. A.; Patil, H. K.; Shirsat, M. D.; Ramanavicius, A.

2017-05-01

Detection of Hg (II) ions using EDTA modified polyaniline (PANI) and single walled carbon nanotubes (SWNTs) nanocomposite (PANI/SWNTs) was performed electrochemically via cyclic voltammetry (CV) technique. Dodecyl benzene sulphonic next step, PANI/SWNTs nanocomposite was modified acid sodium salt (DBSA) was used as a surfactant during this synthesis to get uniform suspension SWNTs. In the by EDTA solution containing crosslinking agent 1-ethyl-3(3-(dimethylamino) propyl) - carbodiimide (EDC) utilizing dip coating technique. The sensitivity of EDTA modified PANI/SWNTs nanocomposite towards Hg (II) ions was investigated. Differential pulse voltammetry (DPV) technique was applied for the electrochemical detection of Hg (II) ions.

Evaluation of in vitro and in vivo biocompatibility of a myo-inositol hexakisphosphate gelated polyaniline hydrogel in a rat model

NASA Astrophysics Data System (ADS)

Sun, Kwang-Hsiao; Liu, Zhao; Liu, Changjian; Yu, Tong; Shang, Tao; Huang, Chen; Zhou, Min; Liu, Cheng; Ran, Feng; Li, Yun; Shi, Yi; Pan, Lijia

2016-04-01

Recent advances in understanding the interaction between electricity and cells/biomolecules have generated great interest in developing biocompatible electrically conductive materials. In this study, we investigated the biocompatibility of a myo-inositol hexakisphosphate gelated polyaniline hydrogel using in vitro and in vivo experiments in a rat model. The polyaniline hydrogel was used to coat a polycaprolactone scaffold and was cultured with rat endothelial progenitor cells differentiated from rat adipose-derived stem cells. Compared with the control sample on a pristine polycaprolactone scaffold, the treated polyaniline hydrogel had the same non-poisonous/cytotoxicity grade, enhanced cell adhesion, and a higher cell proliferation/growth rate. In implant studies, the polyaniline hydrogel sample induced milder inflammatory responses than did the control at the same time points. Combining the advantages of a biocompatible hydrogel and an organic conductor, the inositol phosphate-gelated polyaniline hydrogel could be used in bioelectronics applications such as biosensors, neural probes, cell stimulators, medical electrodes, tissue engineering, and electro-controlled drug delivery.

Combined use of vancomycin-modified Ag-coated magnetic nanoparticles and secondary enhanced nanoparticles for rapid surface-enhanced Raman scattering detection of bacteria.

PubMed

Wang, Chongwen; Gu, Bing; Liu, Qiqi; Pang, Yuanfeng; Xiao, Rui; Wang, Shengqi

2018-01-01

Pathogenic bacteria have always been a significant threat to human health. The detection of pathogens needs to be rapid, accurate, and convenient. We present a sensitive surface-enhanced Raman scattering (SERS) biosensor based on the combination of vancomycin-modified Ag-coated magnetic nanoparticles (Fe 3 O 4 @Ag-Van MNPs) and Au@Ag nanoparticles (NPs) that can effectively capture and discriminate bacterial pathogens from solution. The high-performance Fe 3 O 4 @Ag MNPs were modified with vancomycin and used as bacteria capturer for magnetic separation and enrichment. The modified MNPS were found to exhibit strong affinity with a broad range of Gram-positive and Gram-negative bacteria. After separating and rinsing bacteria, Fe 3 O 4 @Ag-Van MNPs and Au@Ag NPs were synergistically used to construct a very large number of hot spots on bacteria cells, leading to ultrasensitive SERS detection. The dominant merits of our dual enhanced strategy included high bacterial-capture efficiency (>65%) within a wide pH range (pH 3.0-11.0), a short assay time (<30 min), and a low detection limit (5×10 2 cells/mL). Moreover, the spiked tests show that this method is still valid in milk and blood samples. Owing to these capabilities, the combined system enabled the sensitive and specific discrimination of different pathogens in complex solution, as verified by its detection of Gram-positive bacterium Escherichia coli , Gram-positive bacterium Staphylococcus aureus , and methicillin-resistant S. aureus . This method has great potential for field applications in food safety, environmental monitoring, and infectious disease diagnosis.

Glycyrrhetinic acid-modified chitosan nanoparticles enhanced the effect of 5-fluorouracil in murine liver cancer model via regulatory T-cells

PubMed Central

Cheng, Mingrong; Xu, Hongzhi; Wang, Yong; Chen, Houxiang; He, Bing; Gao, Xiaoyan; Li, Yingchun; Han, Jiang; Zhang, Zhiping

2013-01-01

Modified chitosan nanoparticles are a promising platform for drug, such as 5-fluorouracil (5-FU), gene, and vaccine delivery. Here, we used chitosan and hepatoma cell-specific binding molecule glycyrrhetinic acid (GA) to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by infrared spectroscopy and hydrogen nuclear magnetic resonance. By combining GA-CTS and 5-FU, we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 193.7 nm, drug loading of 1.56%, and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained-release system comprising three distinct phases of quick, steady, and slow release. In vitro data indicated that it had a dose- and time-dependent anticancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited cancer cell proliferation, resulting in increased survival time. The antitumor mechanisms for GA-CTS/5-FU nanoparticle were possibly associated with an increased expression of regulatory T-cells, decreased expression of cytotoxic T-cell and natural killer cells, and reduced levels of interleukin-2 and interferon gamma. PMID:24187487

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

NASA Astrophysics Data System (ADS)

Kamarudin, Sabariah; Mohammad, Masita

2018-04-01

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

Stability improvement of immobilized lactoperoxidase using polyaniline polymer.

PubMed

Jafary, Fariba; Kashanian, Soheila; Sharieat, Ziadin Samsam; Jafary, Farzaneh; Omidfar, Kobra; Paknejad, Maliheh

2012-12-01

Enzyme engineering via immobilization techniques is perfectly compatible against the other chemical or biological approximate to improve enzyme functions and stability. In this study lactoperoxidase was immobilized onto polyaniline polymer activated with glutaraldehyde as a bifunctional agent, to improve enzyme properties. Polyaniline polymer was used due its unique physical and chemical properties to immobilize lactoperoxidase (LPO). The optimum activity of immobilized LPO was observed at pH 6 and 55 °C, which has been increased about 10 °C for the immobilized enzyme. The immobilized enzyme maintained absolutely active for 60 days whereas the native enzyme lost 80 % of its initial activity within this period of time. Moreover, the immobilized enzyme can be reused for several times without loss of activity. The kinetic parameter studies showed slight differences between free and immobilized enzymes. The K(m) and K(m.app) were calculated to be 0.6 and 0.4; also V(max) and V(max.app) were 1.3 and 0.9 respectively.

Polyaniline-ZnO nanocomposites as ethanol gas sensors

NASA Astrophysics Data System (ADS)

Talegaonkar, Janhavi; Patil, Y. B.; Patil, D. R.

2018-05-01

Polyaniline and it`s nanocomposites with ZnO were successfully synthesized by photo-induced polymerization method with various concentrations of ZnO, followed by characterizations viz. SEM, EDAX, XRD, FTIR and UV-Vis. Thick films of synthesized powders were fabricated by screen printing technique for monitoring various gases at different operating temperatures and at various gas concentrations. CuO activated polyaniline-ZnO nano-composite exhibits maximum response of ethanol gas at room temperature. The sensor exhibits high sensitivity, highest selectivity, quick response, fast recovery, long term stability, etc. An exceptional sensitivity was found to low concentrations of ethanol gas at room temperature and no cross sensitivity was observed even to high concentrations of other hazardous and polluting gases. The efforts have been made to develop the ethanol sensor based on PANI and its nanocomposites. The effects of microstructure and surfactant concentration on the ethanol response, selectivity, response and recovery of the sensor in the presence of ethanol gas were studied and discussed.

Temperature-dependent charge transport mechanisms in carbon sphere/polyaniline composite

NASA Astrophysics Data System (ADS)

Nieves, Cesar A.; Martinez, Luis M.; Meléndez, Anamaris; Ortiz, Margarita; Ramos, Idalia; Pinto, Nicholas J.; Zimbovskaya, Natalya

2017-12-01

Charge transport in the temperature range 80 K < T < 300 K was studied in a composite of carbon spheres (CS), prepared via hydrothermal carbonization of sucrose, and the conducting polymer polyaniline (PANi). PANi was synthesized via the oxidative polymerization of aniline with ammonium peroxydisulfate (APS) in acidic media. The CS/PANi composite was prepared by coating the spheres with a thin polyaniline (PANi) film doped with hydrochloric acid (HCl) in situ during the polymerization process. Temperature dependent conductivity measurements show that three dimensional variable range hopping of electrons between polymeric chains in PANi-filled gaps between CS is the predominant transport mechanism through CS/PANi composites. The high conductivity of the CS/PANi composite makes the material attractive for the fabrication of devices and sensors.

Controllably annealed CuO-nanoparticle modified ITO electrodes: Characterisation and electrochemical studies

NASA Astrophysics Data System (ADS)

Wang, Tong; Su, Wen; Fu, Yingyi; Hu, Jingbo

2016-12-01

In this paper, we report a facile and controllable two-step approach to produce indium tin oxide electrodes modified by copper(II) oxide nanoparticles (CuO/ITO) through ion implantation and annealing methods. After annealing treatment, the surface morphology of the CuO/ITO substrate changed remarkably and exhibited highly electroactive sites and a high specific surface area. The effects of annealing treatment on the synthesis of CuO/ITO were discussed based on various instruments' characterisations, and the possible mechanism by which CuO nanoparticles were generated was also proposed in this work. Cyclic voltammetric results indicated that CuO/ITO electrodes exhibited effective catalytic responses toward glucose in alkaline solution. Under optimal experimental conditions, the proposed CuO/ITO electrode showed sensitivity of 450.2 μA cm-2 mM-1 with a linear range of up to ∼4.4 mM and a detection limit of 0.7 μM (S/N = 3). Moreover, CuO/ITO exhibited good poison resistance, reproducibility, and stability properties.

Enhanced performance of core-shell structured polyaniline at helical carbon nanotube hybrids for ammonia gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Xin; Wang, Qiang; Chen, Xiangnan

2014-11-17

A core-shell structured hybrid of polyaniline at helical carbon nanotubes was synthesized using in situ polymerization, which the helical carbon nanotubes were uniformly surrounded by a layer of polyaniline nanorods array. More interestingly, repeatable responses were experimentally observed that the sensitivity to ammonia gas of the as-prepared helical shaped core-shell hybrid displays an enhancement of more than two times compared to those of only polyaniline or helical carbon nanotubes sensors because of the peculiar structures with high surface area. This kind of hybrid comprising nanorod arrays of conductive polymers covering carbon nanotubes and related structures provide a potential in sensorsmore » of trace gas detection for environmental monitoring and safety forecasting.« less

Peptide Modified ZnO Nanoparticles as Gas Sensors Array for Volatile Organic Compounds (VOCs)

PubMed Central

Mascini, Marcello; Gaggiotti, Sara; Della Pelle, Flavio; Di Natale, Corrado; Qakala, Sinazo; Iwuoha, Emmanuel; Pittia, Paola; Compagnone, Dario

2018-01-01

In this work a peptide based gas sensor array based of ZnO nanoparticles (ZnONPs) has been realized. Four different pentapeptides molecularly modeled for alcohols and esters having cysteine as a common spacer have been immobilized onto ZnONPs. ZnONPs have been morphologically and spectroscopically characterized. Modified nanoparticles have been then deposited onto quartz crystal microbalances (QCMs) and used as gas sensors with nitrogen as carrier gas. Analysis of the pure compounds modeled demonstrated a nice fitting of modeling with real data. The peptide based ZnONPs had very low sensitivity to water, compared to previously studied AuNPs peptide based gas sensors allowing the use of the array on samples with high water content. Real samples of fruit juices have been assayed; stability of the signal, good repeatability, and discrimination ability of the array was achieved. PMID:29713626

Peptide Modified ZnO Nanoparticles as Gas Sensors Array for Volatile Organic Compounds (VOCs).

PubMed

Mascini, Marcello; Gaggiotti, Sara; Della Pelle, Flavio; Di Natale, Corrado; Qakala, Sinazo; Iwuoha, Emmanuel; Pittia, Paola; Compagnone, Dario

2018-01-01

In this work a peptide based gas sensor array based of ZnO nanoparticles (ZnONPs) has been realized. Four different pentapeptides molecularly modeled for alcohols and esters having cysteine as a common spacer have been immobilized onto ZnONPs. ZnONPs have been morphologically and spectroscopically characterized. Modified nanoparticles have been then deposited onto quartz crystal microbalances (QCMs) and used as gas sensors with nitrogen as carrier gas. Analysis of the pure compounds modeled demonstrated a nice fitting of modeling with real data. The peptide based ZnONPs had very low sensitivity to water, compared to previously studied AuNPs peptide based gas sensors allowing the use of the array on samples with high water content. Real samples of fruit juices have been assayed; stability of the signal, good repeatability, and discrimination ability of the array was achieved.

Peptide modified ZnO nanoparticles as gas sensors array for volatile organic compounds (VOCs)

NASA Astrophysics Data System (ADS)

Mascini, Marcello; Gaggiotti, Sara; Della Pelle, Flavio; Di Natale, Corrado; Qakala, Sinazo; Iwuoha, Emmanuel; Pittia, Paola; Compagnone, Dario

2018-04-01

In this work a peptide based gas sensor array based of ZnO nanoparticles (ZnONPs) has been realized. Four different pentapeptides molecularly modelled for alcohols and esters having cysteine as a common spacer have been immobilized onto ZnONPs. ZnONPs have been morphologically and spectroscopically characterized. Modified nanoparticles have been then deposited onto quartz crystal microbalances (QCMs) and used as gas sensors with nitrogen as carrier gas. Analysis of the pure compounds modelled demonstrated a nice fitting of modelling with real data. The peptide based ZnONPs had very low sensitivity to water, compared to previously studied AuNPs peptide based gas sensors allowing the use of the array on samples with high water content. Real samples of fruit juices have been assayed; stability of the signal, good repeatability and discrimination ability of the array was achieved.

Effects of MgO modified β-TCP nanoparticles on the microstructure and properties of β-TCP/Mg-Zn-Zr composites.

PubMed

Zheng, H R; Li, Z; You, C; Liu, D B; Chen, M F

2017-03-01

The mechanical properties and corrosion resistance of magnesium alloy composites were improved by the addition of MgO surface modified tricalcium phosphate ceramic nanoparticles (m-β-TCP). Mg-3Zn-0.8Zr composites with unmodified (MZZT) and modified (MZZMT) nanoparticles were produced by high shear mixing technology. Effects of MgO m-β-TCP nanoparticles on the microstructure, mechanical properties, electrochemical corrosion properties and cytocompatibility of Mg-Zn-Zr/β-TCP composites were investigated. After hot extrusion deformation and dynamic recrystallization, the grain size of MZZMT was the half size of MZZT and the distribution of m-β-TCP particles in the matrix was more uniform than β-TCP particles. The yield tensile strength (YTS), ultimate tensile strength (UTS), and corrosion potential (Ecorr) of MZZMT were higher than MZZT; the corrosion current density (I corr ) of MZZMT was lower than MZZT. Cell proliferation of co-cultured MZZMT and MZZT composite samples were roughly the same and the cell number at each time point is higher for MZZMT than for MZZT samples.

Block Copolymer as a Surface Modifier to Monodisperse Patchy Silica Nanoparticles for Superhydrophobic Surfaces.

PubMed

Lou, Shuo; Wang, Junzheng; Yin, Xiaohong; Qu, Wenxiu; Song, Yuexiao; Xin, Feng; Qaraah, Fahim Abdo Ali

2018-06-18

Monodisperse patchy silica nanoparticles (PSNPs) less than 100 nm are prepared based on the seed-regrowth method using a poly(ethylene oxide) (PEO)-poly(propylene oxide) (PPO)-PEO-type block copolymer as a surface modifier. Well-defined patches are controllably synthesized through area-selective deposition of silica onto the surface of seeds. After colloidal PSNPs are further modified with trimethylchlorosilane, the advancing and receding contact angles of water for PSNPs are 168 ± 2° and 167 ± 2°, respectively. The superhydrophobic and transparent coatings on the various types of substrates are obtained by a simple drop-casting procedure. Additionally, almost the same superhydrophobicity can be achieved by using colloidal PSNPs via redispersing the powder of superhydrophobic PSNPs in ethanol.

The effects of bacteria-nanoparticles interface on the antibacterial activity of green synthesized silver nanoparticles.

PubMed

Ahmad, Aftab; Wei, Yun; Syed, Fatima; Tahir, Kamran; Rehman, Aziz Ur; Khan, Arifullah; Ullah, Sadeeq; Yuan, Qipeng

2017-01-01

Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 μg/mL) and 18 ± 1.6 mm (MIC = 12.50 μg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 μg/mL) and Bacillus subtilus (MIC = 12.50 μg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles

Highly active, bi-functional and metal-free B4C-nanoparticle-modified graphite felt electrodes for vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Jiang, H. R.; Shyy, W.; Wu, M. C.; Wei, L.; Zhao, T. S.

2017-10-01

The potential of B4C as a metal-free catalyst for vanadium redox reactions is investigated by first-principles calculations. Results show that the central carbon atom of B4C can act as a highly active reaction site for redox reactions, due primarily to the abundant unpaired electrons around it. The catalytic effect is then verified experimentally by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests, both of which demonstrate that B4C nanoparticles can enhance the kinetics for both V2+/V3+ and VO2+/VO2+ redox reactions, indicating a bi-functional effect. The B4C-nanoparticle-modified graphite felt electrodes are finally prepared and tested in vanadium redox flow batteries (VRFBs). It is shown that the batteries with the prepared electrodes exhibit energy efficiencies of 88.9% and 80.0% at the current densities of 80 and 160 mA cm-2, which are 16.6% and 18.8% higher than those with the original graphite felt electrodes. With a further increase in current densities to 240 and 320 mA cm-2, the batteries can still maintain energy efficiencies of 72.0% and 63.8%, respectively. All these results show that the B4C-nanoparticle-modified graphite felt electrode outperforms existing metal-free catalyst modified electrodes, and thus can be promising electrodes for VRFBs.

Determination of morphological characteristics of metallic nanoparticles based on modified Maxwell-Garnett fitting of optical responses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Battie, Y., E-mail: yann.battie@univ-lorraine.fr; Resano-Garcia, A.; En Naciri, A.

2015-10-05

A modified effective medium theory (MEMT) is introduced to determine morphological characteristics and the volume fraction of colloidal metallic nanoparticles. By analyzing the optical absorption spectra of gold nanoparticles (NPs), this model is used to determine the distribution of prolate and oblate NPs and to demonstrate the presence of spherical NPs. In addition to interband transition, the model takes into account the longitudinal and transversal surface plasmon resonances. The results predicted by the MEMT theory were found to be in very good agreement with the shape distributions obtained by transmission electron microscopy. We found that fitting optical absorption spectra usingmore » MEMT provides a robust tool for measuring the shape and concentration of metallic NPs.« less

Resonance light-scattering spectrometric study of interaction between enzyme and MPA-modified CdTe nanoparticles

NASA Astrophysics Data System (ADS)

Li, Juan; Li, Minjie; Tang, Jieli; Li, Xiaozhou; Zhang, Hanqi; Zhang, Yihua

2008-08-01

This paper described a novel assay of enzyme based on the measurement of enhanced resonance light-scattering (RLS) signals resulting from the electrostatic and coordination interaction of functionalized CdTe nanoparticles with enzyme. The CdTe nanoparticles which were modified with 3-mercaptocarboxylic acid (MPA) have abundant carboxylic groups ( sbnd COOH). So the nanoparticles are water-soluble, stable and biocompatible. At pH 8.3 phosphate buffered saline (PBS), the RLS signals of functionalized nano-CdTe are greatly enhanced by bromelain and papain in the region of 220-800 nm characterized by the peak around 318-314 nm, respectively. The optimization conditions of the reaction were also examined and selected. Under the selected conditions, the enhanced RLS intensity is linearly proportional to the concentration of bromelain and papain. The liner range is (0.09-0.9) × 10 -6 mol/L for bromelain and (0.048-0.702) × 10 -6 mol/L for papain. The influences of some foreign substances were also examined. This method can be applied to the determination of enzyme.

The Enhanced Photo-Electrochemical Detection of Uric Acid on Au Nanoparticles Modified Glassy Carbon Electrode

NASA Astrophysics Data System (ADS)

Shi, Yuting; Wang, Jin; Li, Shumin; Yan, Bo; Xu, Hui; Zhang, Ke; Du, Yukou

2017-07-01

In this work, a sensitive and novel method for determining uric acid (UA) has been developed, in which the glassy carbon electrode (GCE) was modified with electrodeposition Au nanoparticles and used to monitor the concentration of UA with the assistant of visible light illumination. The morphology of the Au nanoparticles deposited on GCE surface were characterized by scanning electron microscope (SEM) and the nanoparticles were found to be well-dispersed spheres with the average diameter approaching 26.1 nm. A series of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements have revealed that the introduction of visible light can greatly enhance both the strength and stability of response current due to the surface plasmon resonance (SPR). Specifically, the DPV showed a linear relationship between peak current and UA concentration in the range of 2.8 to 57.5 μM with the equation of I pa (μA) = 0.0121 c UA (μM) + 0.3122 ( R 2 = 0.9987). Herein, the visible light illuminated Au/GCE possesses a potential to be a sensitive electrochemical sensor in the future.

Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with copper nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sophia, J.; Muralidharan, G., E-mail: muraligru@gmail.com

2015-10-15

In this paper, fabrication of glassy carbon electrode (GCE) modified with nano copper particles is discussed. The modified electrode has been tested for the non-enzymatic electrochemical detection of hydrogen peroxide (H{sub 2}O{sub 2}). The copper nanoparticles (Cu NPs) were prepared employing a simple chemical reduction method. The presence of Cu NPs was confirmed through UV–visible (UV–vis) absorption spectroscopy and X-ray diffraction (XRD) analysis. The size and morphology of the particles were investigated using transmission electron microscopy (TEM). The electrochemical properties of the fabricated sensor were studied via cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The electrochemical sensor displayedmore » excellent performance features towards H{sub 2}O{sub 2} detection exhibiting wide linear range, low detection limit, swift response time, good reproducibility and stability.« less

Method for preparing polyaniline fibers

DOEpatents

Mattes, Benjamin R.; Wang, Hsing-Lin

2000-01-01

Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (>15% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.

Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

NASA Astrophysics Data System (ADS)

Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

2015-01-01

The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

Electrochemical determination of dopamine and ascorbic acid at a novel gold nanoparticles distributed poly(4-aminothiophenol) modified electrode.

PubMed

Gopalan, Anantha Iyengar; Lee, Kwang-Pill; Manesh, Kalayil Manian; Santhosh, Padmanabhan; Kim, Jun Heon; Kang, Jae Soo

2007-03-15

A modified electrode is fabricated by embedding gold nanoparticles into a layer of electroactive polymer, poly(4-aminothiophenol) (PAT) on the surface of glassy carbon (GC) electrode. Cyclic voltammetry (CV) is performed to deposit PAT and concomitantly deposit Au nanoparticles. Field emission transmission electron microscopic image of the modified electrode, PAT-Au(nano)-ME, indicates the presence of uniformly distributed Au nanoparticles having the sizes of 8-10nm. Electrochemical behavior of the PAT-Au(nano)-ME towards detection of ascorbic acid (AA) and dopamine (DA) is studied using CV. Electrocatalytic determination of DA in the presence of fixed concentration of AA and vice versa, are studied using differential pulse voltammetry (DPV). PAT-Au(nano)-ME exhibits two well defined anodic peaks at the potential of 75 and 400mV for the oxidation of AA and DA, respectively with a potential difference of 325mV. Further, the simultaneous determination of AA and DA is studied by varying the concentration of AA and DA. PAT-Au(nano)-ME exhibits selectivity and sensitivity for the simultaneous determination of AA and DA without fouling by the oxidation products of AA or DA. PAT and Au nanoparticles provide synergic influence on the accurate electrochemical determination of AA or DA from a mixture having any one of the component (AA or DA) in excess. The practical analytical utilities of the PAT-Au(nano)-ME are demonstrated by the determination of DA and AA in dopamine hydrochloride injection and human blood serum samples.

Cadmium removal from water using thiolactic acid-modified titanium dioxide nanoparticles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skubal, L. R.; Meshkov, N. K.; Rajh, T.

2002-05-31

This study investigated the use of titanium dioxide (TiO{sub 2}) nanoparticles to remove aqueous cadmium from simulated wastewaters. Nanosized (45 A) colloids of anatase TiO{sub 2} were synthesized through the controlled hydrolysis of TiCl4 and their surfaces modified with the bidental chelating agent thiolactic acid (TLA). Colloids were introduced into 65 ppm cadmium-laden waters, and the suspensions were purged aerobically, anoxically with an inert gas, or by a sequential aerobic/anoxic purge. Suspensions were illuminated with 253.7 nm light. In each experiment, samples were taken from the reactor, filtered, and the filtrates analyzed by atomic absorption spectroscopy for residual cadmium. Resultsmore » from the aerobic experiments exhibited minimal (approximately 10%) removal of the cadmium from solution and no reduction of the metal on either the modified or the unmodified colloid. Anoxic results were more promising, showing no cadmium reduction on the unmodified colloid but a 40% adsorption and reduction (from a +2 valence state to elemental cadmium as determined by methyl viologen tests) of cadmium on TLA-modified colloid in the presence of light. Results from the mixed atmospheric conditions fared the best and demonstrated that in the absence of light, approximately 20% of aqueous cadmium was sorbed to the modified colloid via a Freundlich adsorption isotherm. Upon illumination, greater than 90% of cadmium was removed by both adsorption and reduction processes onto the TLA-modified TiO{sub 2}. These removal and reduction processes were catalytic in nature. Results from this study are significant because to date, no other research in the literature has been able to accomplish cadmium removal and reduction using TiO{sub 2}.« less

Excellent electrochemical performances of cabbage-like polyaniline fabricated by template synthesis

NASA Astrophysics Data System (ADS)

Hu, Chenglong; Chen, Shaoyun; Wang, Yuan; Peng, Xianghong; Zhang, Weihong; Chen, Jian

2016-07-01

In this article, we explore a novel route to fabricate cabbage-like polyaniline (PANI) by in situ polymerization of aniline using the hydroxylated poly (methyl methacrylate) nanospheres (i.e. PMMAsbnd OHsbnd NS) as a template. A maximum specific capacitance of 584 F/g (the current density is 0.1 A/g) is achieved at 10 mV s-1 as well as a high stability of over 3000 cycles (the decrease in the SC is ∼9.1%), which suggests the potential application of the cabbage-like polyaniline in supercapacitors. The predominant electrochemical performances of the cabbage-like polyaniline can be attributed to their large surface area and larger-scale π-π conjugated system present in the quinoid structure of the PANI molecular chain, which can drastically facilitate electron diffusion and improve the utilization of the electroactive PANI during the charge/discharge processes. Accordingly, the facility of charge transfer can decrease resistance along with the PANI molecular chain to improve the electrochemical stability and achieve high-capacitance response characteristics. The present study introduces a new synthesis method for the development of various morphology of other conducting polymer, which may find potential applications in a variety of high-performance electrochemical devices.

Preparation and electrochemical capacitance performances of super-hydrophilic conducting polyaniline

NASA Astrophysics Data System (ADS)

Li, Xingwei; Li, Xiaohan; Dai, Na; Wang, Gengchao; Wang, Zhun

Super-hydrophilic conducting polyaniline was prepared by surface modification of polyaniline using tetraethyl orthosilicate in water/ethanol solution, whereas its conductivity was 4.16 S cm -1 at 25 °C. And its electrochemical capacitance performances as an electrode material were evaluated by the cyclic voltammetry and galvanostatic charge/discharge test in 0.1 M H 2SO 4 aqueous solution. Its initial specific capacitance was 500 F g -1 at a constant current density of 1.5 A g -1, and the capacitance still reached about 400 F g -1 after 5000 consecutive cycles. Moreover, its capacitance retention ratio was circa 70% with the growth of current densities from 1.5 to 20 A g -1, indicating excellent rate capability. It would be a promising electrode material for aqueous redox supercapacitors.

Pulsed electric field assisted assembly of polyaniline

NASA Astrophysics Data System (ADS)

Kumar, Arun; Kazmer, David O.; Barry, Carol M. F.; Mead, Joey L.

2012-08-01

Assembling conducting polyaniline (PANi) on pre-patterned nano-structures by a high rate, commercially viable route offers an opportunity for manufacturing devices with nanoscale features. In this work we report for the first time the use of pulsed electric field to assist electrophoresis for the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 s, assembly resolution of 100 nm). Moreover, the area coverage increases with the increase in number of pulses. A similar trend was observed with the deposition height and the increase in deposition height followed a linear trend with a correlation coefficient of 0.95. When the experimental mass deposited was compared with Hamaker’s theoretical model, the two were found to be very close. The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to thermoplastic polyurethane using the thermoforming process.

Combined use of vancomycin-modified Ag-coated magnetic nanoparticles and secondary enhanced nanoparticles for rapid surface-enhanced Raman scattering detection of bacteria

PubMed Central

Pang, Yuanfeng; Xiao, Rui; Wang, Shengqi

2018-01-01

Background Pathogenic bacteria have always been a significant threat to human health. The detection of pathogens needs to be rapid, accurate, and convenient. Methods We present a sensitive surface-enhanced Raman scattering (SERS) biosensor based on the combination of vancomycin-modified Ag-coated magnetic nanoparticles (Fe3O4@Ag-Van MNPs) and Au@Ag nanoparticles (NPs) that can effectively capture and discriminate bacterial pathogens from solution. The high-performance Fe3O4@Ag MNPs were modified with vancomycin and used as bacteria capturer for magnetic separation and enrichment. The modified MNPS were found to exhibit strong affinity with a broad range of Gram-positive and Gram-negative bacteria. After separating and rinsing bacteria, Fe3O4@Ag-Van MNPs and Au@Ag NPs were synergistically used to construct a very large number of hot spots on bacteria cells, leading to ultrasensitive SERS detection. Results The dominant merits of our dual enhanced strategy included high bacterial-capture efficiency (>65%) within a wide pH range (pH 3.0–11.0), a short assay time (<30 min), and a low detection limit (5×102 cells/mL). Moreover, the spiked tests show that this method is still valid in milk and blood samples. Owing to these capabilities, the combined system enabled the sensitive and specific discrimination of different pathogens in complex solution, as verified by its detection of Gram-positive bacterium Escherichia coli, Gram-positive bacterium Staphylococcus aureus, and methicillin-resistant S. aureus. Conclusion This method has great potential for field applications in food safety, environmental monitoring, and infectious disease diagnosis. PMID:29520142

Photo-cured PMMA/PEI core/shell nanoparticles surface-modified with Gd-DTPA for T1 MR imaging.

PubMed

Ratanajanchai, Montri; Lee, Don Haeng; Sunintaboon, Panya; Yang, Su-Geun

2014-02-01

Herein, we introduced amine-functionalized core-shell nanoparticles (Polymethyl methacrylate/Polyethyleneimine; PMMA/PEI) with surface primary amines (3.15×10(5) groups/particle) and uniform size distribution (150-200nm) that were prepared by one-step photo-induced emulsion polymerization. Further PEI-surface was modified with diethylenetriamine pentaacetic acid (DTPA) and introduced with Gd(III). The modified particles possessing DTPA can entrap a high content of Gd(III) ions of over 5.5×10(4)Gd/particle with stable chelation (no release of free Gd) at least 7h. The Gd-DTPA-conjugated core-shell nanoparticles (PMMA/PEI-DTPA-Gd NPs) enhanced the MRI intensity more than Primovist (a commercial hepatic contrast agent). Moreover, the PMMA/PEI-DTPA-Gd NPs showed non-cytotoxicity up to 250μM in normal liver cells. Thus, in vitro data suggested the PMMA/PEI-DTPA-Gd NPs is promising delivery system as a superior MRI contrast agent, especially for hepatic lesion targeted MR imaging. Copyright © 2013 Elsevier Inc. All rights reserved.

Ionic liquid-functionalized carbon nanoparticles-modified cathode for efficiency enhancement in polymer solar cells

NASA Astrophysics Data System (ADS)

Chen, Xiaohong; Yang, Jiaxiang; Lu, Jiong; Manga, Kiran Kumar; Loh, Kian Ping; Zhu, Furong

2009-09-01

The power conversion efficiency (PCE) of regioregular poly(3-hexylthiophene) (P3HT) and {6,6}-phenyl C61-butyric acid methylester (PCBM)-based polymer solar cells was increased using an ionic liquid-functionalized carbon nanoparticles (ILCNs) thin film-modified cathode. The PCE of P3HT:PCBM based-polymer solar cells with a conventional aluminum (Al)-only cathode was increased by 20%-30% when the identical devices were made with an ILCNs-modified Al cathode, but its PCE was 10% lower than that of devices with LiF/Al cathode, measured under AM1.5G illumination of 100 mW/cm2. The ILCN interlayer approach, however, offers practical advantages to LiF in terms of its solution-processability, which is compatible with low cost, large area, and flexible solar cell fabrication.

Property influence of polyanilines on photovoltaic behaviors of dye-sensitized solar cells.

PubMed

Tan, Shuxin; Zhai, Jin; Xue, Bofei; Wan, Meixiang; Meng, Qingbo; Li, Yuliang; Jiang, Lei; Zhu, Daoben

2004-03-30

The influence of polyanilines (PANIs) as hole conductors on the photovoltaic behaviors of dye-sensitized solar cells is studied. The current-voltage (I-V) characteristics and the incident photon to current conversion efficiency (IPCE) curves of the devices are determined as the function of different conductivities and morphologies of PANIs. The results show that the conductivity of PANIs affects the performance of the devices greatly, and PANI with the intermediate conductivity value (3.5 S/cm) is optimum. In addition, the effects of both the film formation property and the cluster size of polyanilines on the photovoltaic behaviors of the devices are also discussed.

Room temperature ammonia sensing using tapered multimode fiber coated with polyaniline nanofibers.

PubMed

Ibrahim, S A; Rahman, N A; Abu Bakar, M H; Girei, S H; Yaacob, M H; Ahmad, H; Mahdi, M A

2015-02-09

We demonstrate an ammonia sensor composed of a tapered multimode fiber coated with polyaniline nanofibers that operates at room temperature (26°C). The optical properties of the polyaniline layer changes when it is exposed to ammonia, leading to a change in the absorption of evanescent field. The fiber sensor was tested by exposing it to ammonia at different concentrations and the absorbance is measured using a spectrophotometer system. Measured response and recovery times are about 2.27 minutes and 9.73 minutes, respectively. The sensor sensitivity can be controlled by adjusting the tapered fiber diameter and the highest sensitivity is achieved when the diameter is reduced to 20 µm.

Elucidation of stabilizing oil-in-water Pickering emulsion with different modified maize starch-based nanoparticles.

PubMed

Ye, Fan; Miao, Ming; Jiang, Bo; Campanella, Osvaldo H; Jin, Zhengyu; Zhang, Tao

2017-08-15

The aim of present study was to study the medium-chain triacylglycerol-in-water (O/W) Pickering emulsion stabilized using different modified starch-based nanoparticles (octenylsuccinylation treated soluble starch nanoparticle, OSA-SSNP, and insoluble starch nanoparticle, ISNP). The major factors for affecting the system stability, rheological behaviour and microstructure of the emulsions were also investigated. The parameters of the O/W emulsions stabilized by OSA-SSNP or ISNP were selected as follows: 3.0% of starch nanoparticles concentration, 50% of MCT fraction and 7.0 of system pH. The rheological properties indicated that both emulsions displayed shear-thinning behaviour as a non-Newtonian fluid. For OSA-SSNP, the viscosities of the emulsion were higher than those of ISNP throughout shear rate range for the same condition. The plot of droplet size distribution for emulsion stabilized OSA-SSNP appeared as a single narrow peak, whereas a broader droplet size distribution with bimodal pattern was observed for emulsion stabilized ISNP. The microscopy results showed that both OSA-SSNP and ISNP were adsorbed at oil-water interface to form a barrier film and retard the phase separation. When emulsion was stored for 30d, no phase separation was detected for O/W emulsion, revealing high stability of emulsion stabilized by both OSA-SSNP and ISNP. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surface-modified multifunctional MIP nanoparticles

NASA Astrophysics Data System (ADS)

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2013-04-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics.

PubMed

Ahmed, Osama A A; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid-liquid phase separation method, according to the Box-Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance.

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics

PubMed Central

Ahmed, Osama AA; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid–liquid phase separation method, according to the Box–Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance. PMID:25670883

Undoped Polyaniline/Surfactant Complex for the Corrosion Prevention

NASA Technical Reports Server (NTRS)

Liu, Lo-Min; Levon, Kalle

1998-01-01

Due to the strict regulations on the usage of heavy metals as the additives in the coating industries, the search for effective organic corrosion inhibitors in replace of those metal additives has become essential. Electrically conducting polymers have been shown to be effective for corrosion prevention but the poor solubility of these intractable polymers has been a problem. We have explored a polyaniline/4-dodecylphenol complex (PANi/DDPh) to improve the dissolution and it has been shown to be an effective organic corrosion inhibitor. With the surfactant, DDPh, PANi could be diluted into the coatings and the properties of the coatings were affected. Emeraldine base (EB) form of PANi was also found to be oxidized by the hardener. The oxidized form of polyaniline provides improved corrosion protection of metals than that of emeraldine base since the value of the standard electrode potential for the oxidized form of PANi is higher than that of EB. Additionally, the surfactant improves the wet adhesion property between the coating and the metal surface.

Investigation into the ring-substituted polyanilines and their application for the detection and adsorption of sulfur dioxide

PubMed Central

Tian, Yuhong; Qu, Ke; Zeng, Xiangqun

2017-01-01

It has been demonstrated in this study that the substituents on the monomer aniline benzene ring are able to introduce the significant differences to the resulting polyaniline’s collective properties. We systematically evaluated the structural perturbation effects of two substituents (methyl and methoxy) of aniline monomer through the electrochemical method. Our results showed that the methoxy group induces the less structural perturbation than the methyl counterpart, because of its partial double bond restriction. The morphologies are different for the polyaniline and the ring-substituted polyanilines, in which substituted polyanilines feature the larger porosities with the addition of these side groups. The influential effects of the methoxy side group have been further illustrated and amplified by its superior sensing performance towards the environmentally-significant sulfur dioxide gas, evaluated through the construction of the quartz crystal microbalance (QCM)-based gas sensor with these polyaniline materials. The as-constructed gas sensor’s sensitivity, selectivity and stability in terms of its SO2 responses have been evaluated in details. The methoxy-substituted polyaniline was tested to show the unique gas sensing properties for the sulfur dioxide at the low concentrations (50–250 ppm) and function as the adsorbing material at the high concentrations (500–1250 ppm). Thus it can be used both as sensing material as well as a novel filter and/or storage reservoir for the removal of sulfur dioxide pollutant from the environments. PMID:29033497

Reflectometric measurement of n-hexane adsorption on ZnO2 nanohybrid film modified by hydrophobic gold nanoparticles

NASA Astrophysics Data System (ADS)

Sebők, Dániel; Csapó, Edit; Ábrahám, Nóra; Dékány, Imre

2015-04-01

Zinc-peroxide/poly(styrenesulfonate) nanohybrid thin films (containing 20 bilayers: [ZnO2/PSS]20, d ∼ 500 nm) were prepared using layer-by-layer (LbL) method. The thin film surface was functionalized by different surface modifying agents (silanes, alkylthiols and hydrophobized nanoparticles). Based on the experimental results of quartz crystal microbalance (QCM) and contact angle measurements (as prequalifications) the octanethiol covered gold nanoparticles (OT-AuNPs) were selected for further vapour adsorption studies. Reflectometric interference spectroscopy (RIfS) was used to measure n-hexane vapour adsorption on the original and modified nanohybrid films in a gas flow platform. The thin film provides only the principle of the measurement (by interference phenomenon), the selectivity and hydrophobicity is controlled and enhanced by surface functionalization (by dispersion interaction between the alkyl chains). The interference pattern shift (Δλ) caused by the increase of the optical thickness of the thin film due to vapour adsorption was investigated. It was found that due to the surface functionalization by hydrophobic nanoparticles the effect of water vapour adsorption decreased significantly, while for n-hexane opposite tendency was observed (the effective refractive index and thus the interference pattern shift increased drastically). The correlation between QCM technique and optical method (RIfS) was specified: linear specific adsorbed amount vs. wavelength shift calibration curves were determined in the pr = 0-0.4 relative vapour pressure range. The thin film is suitable for sensorial application (e.g. volatile organic compound/VOC sensor).

Biomedical Properties Study of Modified Chitosan Nanoparticles for Drug Delivery Systems

NASA Astrophysics Data System (ADS)

Saboktakin, Mohammad Reza

2013-09-01

The purpose of this review is to discuss and summarize some of the interesting findings and applications of modified chitosan (MCS) and their derivatives in different areas of drug delivery. This review highlights the important applications of MCS in the design of various novel delivery systems like liposomes, microspheres, microcapsules, and nanoparticles. In addition to their well-known effects on drug solubility and dissolution, bioavailability, safety, and stability, their uses as recipients in drug formulation are also discussed. This review also focuses on various factors influencing inclusion complex formation because an understanding of the same is necessary for proper handling of these versatile materials. Some important considerations in selecting MCS in drug formulation such as their commercial availability, regulatory status, and patent status are also summarized.

Predicting Cell Association of Surface-Modified Nanoparticles Using Protein Corona Structure - Activity Relationships (PCSAR).

PubMed

Kamath, Padmaja; Fernandez, Alberto; Giralt, Francesc; Rallo, Robert

2015-01-01

Nanoparticles are likely to interact in real-case application scenarios with mixtures of proteins and biomolecules that will absorb onto their surface forming the so-called protein corona. Information related to the composition of the protein corona and net cell association was collected from literature for a library of surface-modified gold and silver nanoparticles. For each protein in the corona, sequence information was extracted and used to calculate physicochemical properties and statistical descriptors. Data cleaning and preprocessing techniques including statistical analysis and feature selection methods were applied to remove highly correlated, redundant and non-significant features. A weighting technique was applied to construct specific signatures that represent the corona composition for each nanoparticle. Using this basic set of protein descriptors, a new Protein Corona Structure-Activity Relationship (PCSAR) that relates net cell association with the physicochemical descriptors of the proteins that form the corona was developed and validated. The features that resulted from the feature selection were in line with already published literature, and the computational model constructed on these features had a good accuracy (R(2)LOO=0.76 and R(2)LMO(25%)=0.72) and stability, with the advantage that the fingerprints based on physicochemical descriptors were independent of the specific proteins that form the corona.

Impact of protein modification on the protein corona on nanoparticles and nanoparticle-cell interactions.

PubMed

Treuel, Lennart; Brandholt, Stefan; Maffre, Pauline; Wiegele, Sarah; Shang, Li; Nienhaus, G Ulrich

2014-01-28

Recent studies have firmly established that cellular uptake of nanoparticles is strongly affected by the presence and the physicochemical properties of a protein adsorption layer around these nanoparticles. Here, we have modified human serum albumin (HSA), a serum protein often used in model studies of protein adsorption onto nanoparticles, to alter its surface charge distribution and investigated the consequences for protein corona formation around small (radius ∼5 nm), dihydrolipoic acid-coated quantum dots (DHLA-QDs) by using fluorescence correlation spectroscopy. HSA modified by succinic anhydride (HSAsuc) to generate additional carboxyl groups on the protein surface showed a 3-fold decreased binding affinity toward the nanoparticles. A 1000-fold enhanced affinity was observed for HSA modified by ethylenediamine (HSAam) to increase the number of amino functions on the protein surface. Remarkably, HSAsuc formed a much thicker protein adsorption layer (8.1 nm) than native HSA (3.3 nm), indicating that it binds in a distinctly different orientation on the nanoparticle, whereas the HSAam corona (4.6 nm) is only slightly thicker. Notably, protein binding to DHLA-QDs was found to be entirely reversible, independent of the modification. We have also measured the extent and kinetics of internalization of these nanoparticles without and with adsorbed native and modified HSA by HeLa cells. Pronounced variations were observed, indicating that even small physicochemical changes of the protein corona may affect biological responses.

Antibody modified gold nanoparticles for fast and selective, colorimetric T7 bacteriophage detection.

PubMed

Lesniewski, Adam; Los, Marcin; Jonsson-Niedziółka, Martin; Krajewska, Anna; Szot, Katarzyna; Los, Joanna M; Niedziolka-Jonsson, Joanna

2014-04-16

Herein, we report a colorimetric immunosensor for T7 bacteriophage based on gold nanoparticles modified with covalently bonded anti-T7 antibodies. The new immunosensor allows for a fast, simple, and selective detection of T7 virus. T7 virions form immunological complexes with the antibody modified gold nanoparticles which causes them to aggregate. The aggregation can be observed with the naked eye as a color change from red to purple, as well as with a UV-vis spectrophotometer. The aggregate formation was confirmed with SEM imaging. Sensor selectivity against the M13 bacteriophage was demonstrated. The limit of detection (LOD) is 1.08 × 10(10) PFU/mL (18 pM) T7. The new method was compared with a traditional plaque test. In contrast to biological tests the colorimetric method allows for detection of all T7 phages, not only those biologically active. This includes phage ghosts and fragments of virions. T7 virus has been chosen as a model organism for adenoviruses. The described method has several advantages over the traditional ones. It is much faster than a standard plaque test. It is more robust since no bacteria-virus interactions are utilized in the detection process. Since antibodies are available for a large variety of pathogenic viruses, the described concept is very flexible and can be adapted to detect many different viruses, not only bacteriophages. Contrary to the classical immunoassays, it is a one-step detection method, and no additional amplification, e.g., enzymatic, is needed to read the result.

Characteristics of polyaniline cobalt supported catalysts for epoxidation reactions.

PubMed

Kowalski, Grzegorz; Pielichowski, Jan; Grzesik, Mirosław

2014-01-01

A study of polyaniline (PANI) doping with various cobalt compounds, that is, cobalt(II) chloride, cobalt(II) acetate, and cobalt(II) salen, is presented. The catalysts were prepared by depositing cobalt compounds onto the polymer surface. PANI powders containing cobalt ions were obtained by one- or two-step method suspending PANI in the following acetonitrile/acetic acid solution or acetonitrile and then acetic acid solution. Moreover different ratios of Co(II) : PANI were studied. Catalysts obtained with both methods and at all ratios were investigated using various techniques including AAS and XPS spectroscopy. The optimum conditions for preparation of PANI/Co catalysts were established. Catalytic activity of polyaniline cobalt(II) supported catalysts was tested in dec-1-ene epoxidation with molecular oxygen at room temperature. The relationship between the amount of cobalt species, measured with both AAS and XPS techniques, and the activity of PANI-Co catalysts has been established.

Characteristics of Polyaniline Cobalt Supported Catalysts for Epoxidation Reactions

PubMed Central

Kowalski, Grzegorz; Pielichowski, Jan; Grzesik, Mirosław

2014-01-01

A study of polyaniline (PANI) doping with various cobalt compounds, that is, cobalt(II) chloride, cobalt(II) acetate, and cobalt(II) salen, is presented. The catalysts were prepared by depositing cobalt compounds onto the polymer surface. PANI powders containing cobalt ions were obtained by one- or two-step method suspending PANI in the following acetonitrile/acetic acid solution or acetonitrile and then acetic acid solution. Moreover different ratios of Co(II) : PANI were studied. Catalysts obtained with both methods and at all ratios were investigated using various techniques including AAS and XPS spectroscopy. The optimum conditions for preparation of PANI/Co catalysts were established. Catalytic activity of polyaniline cobalt(II) supported catalysts was tested in dec-1-ene epoxidation with molecular oxygen at room temperature. The relationship between the amount of cobalt species, measured with both AAS and XPS techniques, and the activity of PANI-Co catalysts has been established. PMID:24701183

Chitosan nanoparticles and their Tween 80 modified counterparts disrupt the developmental profile of zebrafish embryos.

PubMed

Yuan, Zhongyue; Li, Ying; Hu, Yulan; You, Jian; Higashisaka, Kazuma; Nagano, Kazuya; Tsutsumi, Yasuo; Gao, Jianqing

2016-12-30

Chitosan nanoparticles (CS-NPs) and their Tween 80 modified counterparts (TmCS-NPs) are among the most commonly used brain-targeted vehicles. However, their potential developmental toxicity is poorly understood. In this study, zebrafish embryos are introduced as an in vivo platform. Both NPs showed a dose-dependent increase in developmental toxicity (decreased hatching rate, increased mortality and incidences of malformation). Neurobehavioral changes included decreased spontaneous movement in TmCS-NP treated embryos and hyperactive effect in CS-NP treated larvae. Both NPs remarkably inhibited axonal development of primary and secondary motor neurons, and affected the muscle structure. Overall, this study demonstrated that CS-NPs and TmCS-NPs could affect embryonic development, disrupt neurobehavior of zebrafish larvae and affect muscle and neuron development, suggesting more attention on biodegradable chitosan nanoparticles. Copyright © 2016 Elsevier B.V. All rights reserved.

Label-Free Electrochemical Detection of Vanillin through Low-Defect Graphene Electrodes Modified with Au Nanoparticles.

PubMed

Gao, Jingyao; Yuan, Qilong; Ye, Chen; Guo, Pei; Du, Shiyu; Lai, Guosong; Yu, Aimin; Jiang, Nan; Fu, Li; Lin, Cheng-Te; Chee, Kuan W A

2018-03-25

Graphene is an excellent modifier for the surface modification of electrochemical electrodes due to its exceptional physical properties and, for the development of graphene-based chemical and biosensors, is usually coated on glassy carbon electrodes (GCEs) via drop casting. However, the ease of aggregation and high defect content of reduced graphene oxides degrade the electrical properties. Here, we fabricated low-defect graphene electrodes by catalytically thermal treatment of HPHT diamond substrate, followed by the electrodeposition of Au nanoparticles (AuNPs) with an average size of ≈60 nm on the electrode surface using cyclic voltammetry. The Au nanoparticle-decorated graphene electrodes show a wide linear response range to vanillin from 0.2 to 40 µM with a low limit of detection of 10 nM. This work demonstrates the potential applications of graphene-based hybrid electrodes for highly sensitive chemical detection.

Preparation and Electrochemical Characterization of Mesoporous Polyaniline-Silica Nanocomposites as an Electrode Material for Pseudocapacitors

PubMed Central

Zu, Lei; Cui, Xiuguo; Jiang, Yanhua; Hu, Zhongkai; Lian, Huiqin; Liu, Yang; Jin, Yushun; Li, Yan; Wang, Xiaodong

2015-01-01

Mesoporous polyaniline-silica nanocomposites with a full interpenetrating structure for pseudocapacitors were synthesized via the vapor phase approach. The morphology and structure of the nanocomposites were deeply investigated by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis and nitrogen adsorption-desorption tests. The results present that the mesoporous nanocomposites possess a uniform particle morphology and full interpenetrating structure, leading to a continuous conductive polyaniline network with a large specific surface area. The electrochemical performances of the nanocomposites were tested in a mixed solution of sulfuric acid and potassium iodide. With the merits of a large specific surface area and suitable pore size distribution, the nanocomposite showed a large specific capacitance (1702.68 farad (F)/g) due to its higher utilization of the active material. This amazing value is almost three-times larger than that of bulk polyaniline when the same mass of active material was used. PMID:28788006

Single Nanoparticle Translocation Through Chemically Modified Solid Nanopore

NASA Astrophysics Data System (ADS)

Tan, Shengwei; Wang, Lei; Liu, Hang; Wu, Hongwen; Liu, Quanjun

2016-02-01

The nanopore sensor as a high-throughput and low-cost technology can detect single nanoparticle in solution. In the present study, the silicon nitride nanopores were fabricated by focused Ga ion beam (FIB), and the surface was functionalized with 3-aminopropyltriethoxysilane to change its surface charge density. The positively charged nanopore surface attracted negatively charged nanoparticles when they were in the vicinity of the nanopore. And, nanoparticle translocation speed was slowed down to obtain a clear and deterministic signal. Compared with previous studied small nanoparticles, the electrophoretic translocation of negatively charged polystyrene (PS) nanoparticles (diameter ~100 nm) was investigated in solution using the Coulter counter principle in which the time-dependent nanopore current was recorded as the nanoparticles were driven across the nanopore. A linear dependence was found between current drop and biased voltage. An exponentially decaying function ( t d ~ e -v/v0 ) was found between the duration time and biased voltage. The interaction between the amine-functionalized nanopore wall and PS microspheres was discussed while translating PS microspheres. We explored also translocations of PS microspheres through amine-functionalized solid-state nanopores by varying the solution pH (5.4, 7.0, and 10.0) with 0.02 M potassium chloride (KCl). Surface functionalization showed to provide a useful step to fine-tune the surface property, which can selectively transport molecules or particles. This approach is likely to be applied to gene sequencing.

Evaluation of adsorption capacities of humic acids extracted from Algerian soil on polyaniline for application to remove pollutants such as Cd(II), Zn(II) and Ni(II) and characterization with cavity microelectrode.

PubMed

Terbouche, Achour; Ramdane-Terbouche, Chafia Ait; Hauchard, Didier; Djebbar, Safia

2011-01-01

The adsorption capacities of new humic acids isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils (Algeria) and commercial humic acid (PFHA) on polyaniline emeraldine base (PEB) were studied at pH 6.6. Also the adsorption of heavy metals such as Cd2+, Zn2+ and Ni2+ on humic acid-polyaniline systems (HA-PEB) was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy (SEM), infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd2+, Zn2+ and Ni2+ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities (q(max)) of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q(max) of Cd2+, Zn2+ and Ni2+ on HA-PEB followed the order: THA-PEB > YHA-PEB > PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.

Cell-Penetrating Peptide-Modified Gold Nanoparticles for the Delivery of Doxorubicin to Brain Metastatic Breast Cancer.

PubMed

Morshed, Ramin A; Muroski, Megan E; Dai, Qing; Wegscheid, Michelle L; Auffinger, Brenda; Yu, Dou; Han, Yu; Zhang, Lingjiao; Wu, Meijing; Cheng, Yu; Lesniak, Maciej S

2016-06-06

As therapies continue to increase the lifespan of patients with breast cancer, the incidence of brain metastases has steadily increased, affecting a significant number of patients with metastatic disease. However, a major barrier toward treating these lesions is the inability of therapeutics to penetrate into the central nervous system and accumulate within intracranial tumor sites. In this study, we designed a cell-penetrating gold nanoparticle platform to increase drug delivery to brain metastatic breast cancer cells. TAT peptide-modified gold nanoparticles carrying doxorubicin led to improved cytotoxicity toward two brain metastatic breast cancer cell lines with a decrease in the IC50 of at least 80% compared to free drug. Intravenous administration of these particles led to extensive accumulation of particles throughout diffuse intracranial metastatic microsatellites with cleaved caspase-3 activity corresponding to tumor foci. Furthermore, intratumoral administration of these particles improved survival in an intracranial MDA-MB-231-Br xenograft mouse model. Our results demonstrate the promising application of gold nanoparticles for improving drug delivery in the context of brain metastatic breast cancer.

Surface-modified multifunctional MIP nanoparticles

PubMed Central

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; de Vargas Sansalvador, Isabel Perez; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2015-01-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly-sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinyl ferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. PMID:23503559

Surface-modified multifunctional MIP nanoparticles.

PubMed

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J; Piletsky, Sergey

2013-05-07

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.

Silver Nanoparticle Modified Electrode Covered by Graphene Oxide for the Enhanced Electrochemical Detection of Dopamine

PubMed Central

Shin, Jae-Wook; Kim, Kyeong-Jun; Yoon, Jinho; Jo, Jinhee; El-Said, Waleed Ahmed; Choi, Jeong-Woo

2017-01-01

Several neurological disorders such as Alzheimer’s disease and Parkinson’s disease have become a serious impediment to aging people nowadays. One of the efficient methods used to monitor these neurological disorders is the detection of neurotransmitters such as dopamine. Metal materials, such as gold and platinum, are widely used in this electrochemical detection method; however, low sensitivity and linearity at low dopamine concentrations limit the use of these materials. To overcome these limitations, a silver nanoparticle (SNP) modified electrode covered by graphene oxide for the detection of dopamine was newly developed in this study. For the first time, the surface of an indium tin oxide (ITO) electrode was modified using SNPs and graphene oxide sequentially through the electrochemical deposition method. The developed biosensor provided electrochemical signal enhancement at low dopamine concentrations in comparison with previous biosensors. Therefore, our newly developed SNP modified electrode covered by graphene oxide can be used to monitor neurological diseases through electrochemical signal enhancement at low dopamine concentrations. PMID:29186040

Silver Nanoparticle Modified Electrode Covered by Graphene Oxide for the Enhanced Electrochemical Detection of Dopamine.

PubMed

Shin, Jae-Wook; Kim, Kyeong-Jun; Yoon, Jinho; Jo, Jinhee; El-Said, Waleed Ahmed; Choi, Jeong-Woo

2017-11-29

Several neurological disorders such as Alzheimer's disease and Parkinson's disease have become a serious impediment to aging people nowadays. One of the efficient methods used to monitor these neurological disorders is the detection of neurotransmitters such as dopamine. Metal materials, such as gold and platinum, are widely used in this electrochemical detection method; however, low sensitivity and linearity at low dopamine concentrations limit the use of these materials. To overcome these limitations, a silver nanoparticle (SNP) modified electrode covered by graphene oxide for the detection of dopamine was newly developed in this study. For the first time, the surface of an indium tin oxide (ITO) electrode was modified using SNPs and graphene oxide sequentially through the electrochemical deposition method. The developed biosensor provided electrochemical signal enhancement at low dopamine concentrations in comparison with previous biosensors. Therefore, our newly developed SNP modified electrode covered by graphene oxide can be used to monitor neurological diseases through electrochemical signal enhancement at low dopamine concentrations.

Dye-doped silica-based nanoparticles for bioapplications

NASA Astrophysics Data System (ADS)

Nhung Tran, Hong; Nghiem, Thi Ha Lien; Thuy Duong Vu, Thi; Tan Pham, Minh; Van Nguyen, Thi; Trang Tran, Thu; Chu, Viet Ha; Thuan Tong, Kim; Thuy Tran, Thanh; Le, Thi Thanh Xuan; Brochon, Jean-Claude; Quy Nguyen, Thi; Nhung Hoang, My; Nguyen Duong, Cao; Thuy Nguyen, Thi; Hoang, Anh Tuan; Hoa Nguyen, Phuong

2013-12-01

This paper presents our recent research results on synthesis and bioapplications of dye-doped silica-based nanoparticles. The dye-doped water soluble organically modified silicate (ORMOSIL) nanoparticles (NPs) with the size of 15-100 nm were synthesized by modified Stöber method from methyltriethoxysilane CH3Si(OCH3)3 precursor (MTEOS). Because thousands of fluorescent dye molecules are encapsulated in the silica-based matrix, the dye-doped nanoparticles are extremely bright and photostable. Their surfaces were modified with bovine serum albumin (BSA) and biocompatible chemical reagents. The highly intensive luminescent nanoparticles were combined with specific bacterial and breast cancer antigen antibodies. The antibody-conjugated nanoparticles can identify a variety of bacterium, such as Escherichia coli O157:H7, through antibody-antigen interaction and recognition. A highly sensitive breast cancer cell detection has been achieved with the anti-HER2 monoclonal antibody-nanoparticles complex. These results demonstrate the potential to apply these fluorescent nanoparticles in various biodetection systems.

Polyaniline coated cellulose fiber / polyvinyl alcohol composites with high dielectric permittivity and low percolation threshold

NASA Astrophysics Data System (ADS)

Anju, V. P.; Narayanankutty, Sunil K.

2016-01-01

Cost effective, high performance dielectric composites based on polyvinyl alcohol, cellulose fibers and polyaniline were prepared and the dielectric properties were studied as a function of fiber content, fiber dimensions and polyaniline content over a frequency range of 40 Hz to 30 MHz. The short cellulose fibers were size-reduced to micro and nano levels prior to coating with polyaniline. Fiber surface was coated with Polyaniline (PANI) by an in situ polymerization technique in aqueous medium. The composites were then prepared by solution casting method. Short cellulose fiber composites showed a dielectric constant (DEC) of 2.3 x 105 at 40 Hz. For the micro- and nano- cellulose fiber composites the DEC was increased to 4.5 x 105 and 1.3 x 108, respectively. To gain insight into the inflection point of the dielectric data polynomial regression analysis was carried out. The loss tangent of all the composites remained at less than 1.5. Further, AC conductivity, real and imaginary electric moduli of all the composites were evaluated. PVA nanocomposite attained an AC conductivity of 3 S/m. These showed that by controlling the size of the fiber used, it was possible to tune the permittivity and dielectric loss to desired values over a wide range. These novel nanocomposites, combining high dielectric constant and low dielectric loss, can be effectively used in applications such as high-charge storage capacitors.

Delivery of phytochemical thymoquinone using molecular micelle modified poly(D, L lactide-co-glycolide) (PLGA) nanoparticles

NASA Astrophysics Data System (ADS)

Ganea, Gabriela M.; Fakayode, Sayo O.; Losso, Jack N.; van Nostrum, Cornelus F.; Sabliov, Cristina M.; Warner, Isiah M.

2010-07-01

Continuous efforts have been made in the development of potent benzoquinone-based anticancer drugs aiming for improved water solubility and reduced adverse reactions. Thymoquinone is a liposoluble benzoquinone-based phytochemical that has been shown to have remarkable antioxidant and anticancer activities. In the study reported here, thymoquinone-loaded PLGA nanoparticles were synthesized and evaluated for physico-chemical, antioxidant and anticancer properties. The nanoparticles were synthesized by an emulsion solvent evaporation method using anionic molecular micelles as emulsifiers. The system was optimized for maximum entrapment efficiency using a Box-Behnken experimental design. Optimum conditions were found for 100 mg PLGA, 15 mg TQ and 0.5% w/v poly(sodium N-undecylenyl-glycinate) (poly-SUG). In addition, other structurally related molecular micelles such as poly(sodium N-heptenyl-glycinate) (poly-SHG), poly(sodium N-undecylenyl-leucinate) (poly-SUL), and poly(sodium N-undecylenyl-valinate) (poly-SUV) were also examined as emulsifiers. All investigated molecular micelles provided excellent emulsifier properties, leading to maximum optimized TQ entrapment efficiency, and monodispersed particle sizes below 200 nm. The release of TQ from molecular micelle modified nanoparticles was investigated by dialysis and reached lower levels than the free drug. The antioxidant activity of TQ-loaded nanoparticles, indicated by IC50 (mg ml - 1 TQ for 50% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity), was highest for poly-SUV emulsified nanoparticles (0.030 ± 0.002 mg ml - 1) as compared to free TQ. In addition, it was observed that TQ-loaded nanoparticles emulsified with poly-SUV were more effective than free TQ against MDA-MB-231 cancer cell growth inhibition, presenting a cell viability of 16.0 ± 5.6% after 96 h.

Interaction of PLGA and trimethyl chitosan modified PLGA nanoparticles with mixed anionic/zwitterionic phospholipid bilayers studied using molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Novak, Brian; Astete, Carlos; Sabliov, Cristina; Moldovan, Dorel

2012-02-01

Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable polymer. Nanoparticles of PLGA are commonly used for drug delivery applications. The interaction of the nanoparticles with the cell membrane may influence the rate of their uptake by cells. Both PLGA and cell membranes are negatively charged, so adding positively charged polymers such as trimethyl chitosan (TMC) which adheres to the PLGA particles improves their cellular uptake. The interaction of 3 nm PLGA and TMC-modified-PLGA nanoparticles with lipid bilayers composed of mixtures of phosphatidylcholine and phosphatidylserine lipids was studied using molecular dynamics simulations. The free energy profiles as function of nanoparticles position along the normal direction to the bilayers were calculated, the distribution of phosphatidylserine lipids as a function of distance of the particle from the bilayer was calculated, and the time scale for particle motion in the directions parallel to the bilayer surface was estimated.

Synthesis, Characterization, and Electrochemical Properties of Polyaniline Thin Films

NASA Astrophysics Data System (ADS)

Rami, Soukaina

Conjugated polymers have been used in various applications (battery, supercapacitor, electromagnetic shielding, chemical sensor, biosensor, nanocomposite, light-emitting-diode, electrochromic display etc.) due to their excellent conductivity, electrochemical and optical properties, and low cost. Polyaniline has attracted the researchers from all disciplines of science, engineering, and industry due to its redox properties, environmental stability, conductivity, and optical properties. Moreover, it is a polymer with fast electroactive switching and reversible properties displayed at low potential, which is an important feature in many applications. The thin oriented polyaniline films have been fabricated using self-assembly, Langmuir-Blodgett, in-situ self-assembly, layer-by-layer, and electrochemical technique. The focus of this thesis is to synthesize and characterize polyaniline thin films with and without dyes. Also, the purpose of this thesis is to find the fastest electroactive switching PANI electrode in different electrolytic medium by studying their electrochemical properties. These films were fabricated using two deposition techniques: in-situ self-assembly and electrochemical deposition. The characterization of these films was done using techniques such as Fourier Transform Infrared Spectroscopy (FTIR), UV-spectroscopy, Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD). FTIR and UV-spectroscopy showed similar results in the structure of the polyaniline films. However, for the dye incorporated films, since there was an addition in the synthesis of the material, peak locations shifted, and new peaks corresponding to these materials appeared. The 1 layer PANI showed compact film morphology, comparing to other PANI films, which displayed a fiber-like structure. Finally, the electrochemical properties of these thin films were studied using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in

Rapid electrochemical detection of polyaniline-labeled Escherichia coli O157:H7.

PubMed

Setterington, Emma B; Alocilja, Evangelyn C

2011-01-15

There is a high demand for rapid, sensitive, and field-ready detection methods for Escherichia coli O157:H7, a highly infectious and potentially fatal food and water borne pathogen. In this study, E. coli O157:H7 cells are isolated via immunomagnetic separation (IMS) and labeled with biofunctionalized electroactive polyaniline (immuno-PANI). Labeled cell complexes are deposited onto a disposable screen-printed carbon electrode (SPCE) sensor and pulled to the electrode surface by an external magnetic field, to amplify the electrochemical signal generated by the polyaniline. Cyclic voltammetry is used to detect polyaniline and signal magnitude indicates the presence or absence of E. coli O157:H7. As few as 7CFU of E. coli O157:H7 (corresponding to an original concentration of 70 CFU/ml) were successfully detected on the SPCE sensor. The assay requires 70 min from sampling to detection, giving it a major advantage over standard culture methods in applications requiring high-throughput screening of samples and rapid results. The method can be performed with portable, handheld instrumentation and no biological modification of the sensor surface is required. Potential applications include field-based pathogen detection for food and water safety, environmental monitoring, healthcare, and biodefense. Copyright © 2010 Elsevier B.V. All rights reserved.

Electrochemical glucose biosensor based on nickel oxide nanoparticle-modified carbon paste electrode.

PubMed

Erdem, Ceren; Zeybek, Derya Koyuncu; Aydoğdu, Gözde; Zeybek, Bülent; Pekyardımcı, Sule; Kılıç, Esma

2014-08-01

In the present work, we designed an amperometric glucose biosensor based on nickel oxide nanoparticles (NiONPs)-modified carbon paste electrode. The biosensor was prepared by incorporation of glucose oxidase and NiONPs into a carbon paste matrix. It showed good analytical performances such as high sensitivity (367 μA mmolL(-1)) and a wide linear response from 1.9×10(-3) mmolL(-1) to 15.0 mmolL(-1) with a limit of detection (0.11 μmolL(-1)). The biosensor was used for the determination of glucose in human serum samples. The results illustrate that NiONPs have enormous potential in the construction of biosensor for determination of glucose.

Human serum albumin nanoparticles modified with apolipoprotein A-I cross the blood-brain barrier and enter the rodent brain.

PubMed

Zensi, Anja; Begley, David; Pontikis, Charles; Legros, Celine; Mihoreanu, Larisa; Büchel, Claudia; Kreuter, Jörg

2010-12-01

Nanoparticles made of human serum albumin (HSA) and modified with apolipoproteins have previously been shown to transport drugs, which normally do not enter the brain, across the blood-brain barrier (BBB). However the precise mechanism by which nanoparticles with different apolipoproteins on their surface can target to the brain, as yet, has not been totally elucidated. In the present study, HSA nanoparticles with covalently bound apolipoprotein A-I (Apo A-I) as a targetor for brain capillary endothelial cells were injected intravenously into SV 129 mice and Wistar rats. The rodents were sacrificed after 15 or 30 min, and their brains were examined by transmission electron microscopy. Apo A-I nanoparticles could be found inside the endothelial cells of brain capillaries as well as within parenchymal brain tissue of both, mice and rats, whereas control particles without Apo A-I on their surface did not cross the BBB during our experiments. The maintenance of tight junction integrity and barrier function during treatment with nanoparticles was demonstrated by perfusion with a fixative containing lanthanum nitrate as an electron dense marker for the permeability of tight junctions.

Electrochromic Behaviors of Water-Soluble Polyaniline with Covalently Bonded Acetyl Ferrocene

NASA Astrophysics Data System (ADS)

Xiong, Shanxin; Wang, Ru; Li, Shuaishuai; Wu, Bohua; Chu, Jia; Wang, Xiaoqin; Zhang, Runlan; Gong, Ming

2018-04-01

A novel ferrocene-containing hybrid electrochromic material was synthesized via copolymerization of aniline with p-phenylenediamine functionalized acetyl ferrocene in the presence of poly (styrene sulfonate) dopant in an aqueous medium, and neat polyaniline (PANI) was prepared for comparison. The polymerization characteristics and the structure of the copolymer were systematically studied by Fourier-transform infrared, meanwhile, their electrochromic properties and electrochemical behaviors were tested by UV-vis spectra, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). It was found that the strong covalent bond and large conjugated system between PANI and ferrocene enhance the electron transfer rate and electron delocalization in the ferrocene-polyaniline (Fc-PANI) hybrid. In particular, the electrochromic device with Fc-PANI as the active layer shows significant enhancement in optical contrast over the PANI-based device.

Biolithography: Slime mould patterning of polyaniline

NASA Astrophysics Data System (ADS)

Berzina, Tatiana; Dimonte, Alice; Adamatzky, Andrew; Erokhin, Victor; Iannotta, Salvatore

2018-03-01

Slime mould Physarum polycephalum develops intricate patterns of protoplasmic networks when foraging on a non-nutrient substrates. The networks are optimised for spanning larger spaces with minimum body mass and for quick transfer of nutrients and metabolites inside the slime mould's body. We hybridise the slime mould's networks with conductive polymer polyaniline and thus produce micro-patterns of conductive networks. This unconventional lithographic method opens new perspectives in development of living technology devices, biocompatible non-silicon hardware for applications in integrated circuits, bioelectronics, and biosensing.

Extracellular biosynthesis of gadolinium oxide (Gd2O3) nanoparticles, their biodistribution and bioconjugation with the chemically modified anticancer drug taxol

PubMed Central

Khan, Shadab Ali; Gambhir, Sanjay

2014-01-01

Summary As a part of our programme to develop nanobioconjugates for the treatment of cancer, we first synthesized extracellular, protein-capped, highly stable and well-dispersed gadolinium oxide (Gd2O3) nanoparticles by using thermophilic fungus Humicola sp. The biodistribution of the nanoparticles in rats was checked by radiolabelling with Tc-99m. Finally, these nanoparticles were bioconjugated with the chemically modified anticancer drug taxol with the aim of characterizing the role of this bioconjugate in the treatment of cancer. The biosynthesized Gd2O3 nanoparticles were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). The Gd2O3–taxol bioconjugate was confirmed by UV–vis spectroscopy and fluorescence microscopy and was purified by using high performance liquid chromatography (HPLC). PMID:24778946

Deactivation of photocatalytically active ZnO nanoparticle and enhancement of its compatibility with organic compounds by surface-capping with organically modified silica

NASA Astrophysics Data System (ADS)

Cao, Zhi; Zhang, Zhijun

2011-02-01

Tetraethyl orthosilicate (TEOS) and dimethyldiethoxysilane (DEDMS) were used as co-precursors to prepare organically modified silica (ormosil) via sol-gel process. The resultant ormosil was adopted for surface-capping of ZnO nanoparticle, where methyl (organic functional group) and silica (inorganic component) were simultaneously introduced onto the surface of the nanoparticles for realizing dual surface-modification. The ormosil-capped ZnO nanoparticle showed strong hydrophobicity and good compatibility with organic phases, as well as effectively decreased photocatalytic activity and almost unchanged ultraviolet (UV)-shielding ability. More importantly, the comprehensive properties of ormosil-capped ZnO nanoparticle could be manipulated by adjusting the molar ratio of TEOS to DEDMS during sol-gel process. This should help to open a wider window to better utilizing the unique and highly attractive properties such as high UV-shielding ability and high-visible light transparency of ZnO nanoparticle in sunscreen cosmetics.

Highly sensitive and selective detection of dopamine based on hollow gold nanoparticles-graphene nanocomposite modified electrode.

PubMed

Zhu, Wencai; Chen, Ting; Ma, Xuemei; Ma, Houyi; Chen, Shenhao

2013-11-01

Highly dispersed hollow gold-graphene (HAu-G) nanocomposites were synthesized by a two-step method. The immobilization of hollow gold nanoparticles (HAu NPs) onto the surface of graphene sheets was achieved by mixing an aqueous solution of HAu NPs with a poly(N-vinylpyrrolidone)-functionalized graphene dispersion at room temperature. A glassy carbon electrode (GCE) was modified with the nanocomposites, and the as-prepared modified electrode displayed high electrocatalytic activity and extraordinary electronic transport properties. Amperometric detection of dopamine (DA) performed with the HAu-G modified electrode exhibits a good linearity between 0.08 and 600 μM with a low detection limit of 0.05 μM (S/N=3) and also possesses good reproducibility and operational stability. The interference of ascorbic acid (AA) and uric acid (UA) can be excluded when using differential pulse voltammetric technique. In addition, this type of modified electrode can also be applied to the determination of DA content in dopamine hydrochloride injection. It is obvious that the HAu-G modified electrode provides a new way to detect dopamine sensitively and selectively. Copyright © 2013 Elsevier B.V. All rights reserved.

An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

NASA Astrophysics Data System (ADS)

Kaçar, Ceren; Dalkiran, Berna; Erden, Pınar Esra; Kiliç, Esma

2014-08-01

In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at -0.30 V (vs. Ag/AgCl). The biosensor showed optimum response within 5 s at pH 7.0. The optimized biosensor showed linear response range of 7.4 × 10-7-1.9 × 10-5 M with a detection limit of 7.4 × 10-7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78 ± 0.89.

Polymeric nanoparticles of cholesterol-modified glycol chitosan for doxorubicin delivery: preparation and in-vitro and in-vivo characterization.

PubMed

Yu, Jing-Mou; Li, Yong-Jie; Qiu, Li-Yan; Jin, Yi

2009-06-01

Polymeric nanoparticles have been extensively studied as drug carriers. Chitosan and its derivatives have attracted significant attention in this regard but have limited application because of insolubility in biological solution. In this work, we attempted to utilize cholesterol-modified glycol chitosan (CHGC) self-aggregated nanoparticles to increase aqueous solubility, and to reduce side effects and enhance the antitumour efficacy of the anticancer drug doxorubicin. Methods CHGC nanoparticles were loaded with doxorubicin by a dialysis method, and their characteristics were determined by transmission electron microscopy examination, light-scattering study, in-vitro drug-release study, pharmacokinetic study in rats and in-vivo antitumour activity in mice. The resulting doxorubicin-loaded CHGC nanoparticles (DCNs) formed self-assembled aggregates in aqueous medium. From the observation by transmission electron microscopy, DCNs were almost spherical in shape. The mean diameters of these nanoparticles determined by dynamic light scattering were in the range of 237-336 nm as the doxorubicin-loading content increased from 1.73% to 9.36%. In-vitro data indicated that doxorubicin release from DCNs was much faster in phosphate-buffered saline at pH 5.5 than at pH 6.5 and 7.4, and the release rate was dependent on the loading content of doxorubicin in these nanoparticles. It was observed that DCN-16 (drug loaded content: 9.36%) exhibited prolonged circulation time in rat plasma and showed higher antitumour efficacy against S180-bearing mice than free doxorubicin. These results indicated that CHGC nanoparticles had potential as a carrier for insoluble anticancer drugs in cancer therapy.

Conducting Polymeric Hydrogel Electrolyte Based on Carboxymethylcellulose and Polyacrylamide/Polyaniline for Supercapacitor Applications

NASA Astrophysics Data System (ADS)

Suganya, N.; Jaisankar, V.; Sivakumar, E. K. T.

Conducting polymer hydrogels represent a unique class of materials that possess enormous application in flexible electronic devices. In the present work, conducting carboxymethylcellulose (CMC)-co-polyacrylamide (PAAm)/polyaniline was synthesized by a two-step interpenetrating network solution polymerization technique. The synthesized CMC-co-PAAm/polyaniline with interpenetrating network structure was prepared by in situ polymerization of aniline to enhance conductivity. The molecular structure and morphology of the copolymer hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The novel conducting polymer hydrogels show good electrical and electrochemical behavior, which makes them potentially useful in electronic devices such as supercapacitors, biosensors, bioelectronics, solar cells and memory devices.

Electropolymerization of Uniform Polyaniline Nanorod Arrays on Conducting Oxides as Counter Electrodes in Dye-Sensitized Solar Cells.

PubMed

He, Ziming; Liu, Jing; Khoo, Si Yun; Tan, Timothy Thatt Yang

2016-01-01

Conventional techniques for the synthesis of oriented polyaniline (PANI) nanostructures are often complex or time consuming. Through an innovative reduced graphene oxide (rGO) modified FTO and a low-potential electropolymerization strategy, the rapid and template-free growth of a highly ordered PANI nanorod array on the FTO substrate is realized. The highly ordered nanostructure of the PANI array leads to a high electrocatalytic activity and chemical stability. The importance of the polymerization potential and rGO surface modification to achieve this nanostructure is revealed. Compared to platinum, the PANI nanorod array exhibits an enhanced performance and stability as counter electrodes in dye-sensitized solar cells, with a 17.6 % enhancement in power conversion efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impedimetric detection of cocaine by using an aptamer attached to a screen printed electrode modified with a dendrimer/silver nanoparticle nanocomposite.

PubMed

Roushani, Mahmoud; Shahdost-Fard, Faezeh

2018-03-12

The authors describe a highly sensitive method for the aptamer (Apt) based impedimetric determination of cocaine. The surface of a screen-printed electrode (SPE) was modified with a nanocomposite of dendrimer and silver nanoparticles (AgNPs). The cocaine-binding Apt was attached to a dendrimer/AgNP/SPE surface, forming a sensitive layer for the determination of cocaine. The incubation with the analyte resulted in the formation of a cocaine/Apt complex on the electrode surface. As a consequence, folding and conformational change in the aptamer structure was induced, this resulting in a change in the impedimetric signal. The aptaassay exhibits highly efficient sensing characteristics with a good linearity of 1 fmol L -1 to 100 nmol L -1 (with two linear ranges) and a limit of detection (LOD) of 333 amol L -1 . Its excellent specificity and high sensitivity suggest that this kind of aptamer-based assay may be applied to detect other targets in this field. Graphical Abstract Designing of an aptaassay via immobilization of a functionalized aptamer with silver nanoparticle (AgNPs-Apt) on the modified screen-printed electrode (SPE) with dendrimer/silver nanoparticle nanocomposite (Den-AgNPs) for impedimetric detection of cocaine.

Enhanced photocatalytic degradation of methylene blue by metal-modified silicon nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brahiti, N., E-mail: dihiabrahiti@yahoo.fr; Université Mouloud MAMMERI de TiziOuzou, Département de Physique, Bastos; Hadjersi, T., E-mail: hadjersi@gmx.com

2015-02-15

Highlights: • SiNWs modified with Pd, Au and Pt were used as photocatalysts to degrade MB. • Yield of photodegardation increases with UV irradiation time. • SiNWs modified with Pd nanoparticles show the best photocatalytic activity. • A degradation of 97% was obtained after 200 min of UV irradiation. - Abstract: Silicon nanowires (SiNWs) modified with Au, Pt and Pd nanoparticles were used as heterogeneous photocatalysts for the photodegradation of methylene blue in water under UV light irradiation. The modification of SiNWs was carried out by deposition of metal nanoparticles using the electroless metal deposition (EMD) technique. The effect ofmore » metal nanoparticles deposition time on the photocatalytic activity was studied. It was found that the photocatalytic activity of modified SiNWs was enhanced when the deposition time of metal nanoparticles was increased. In addition of modified SiNWs with Pt, Au and Pd nanoparticles, oxidized silicon substrate (Ox-Si), oxidized silicon nanowires (Ox-SiNWs) and hydrogen-terminated silicon nanowires (H-SiNWs) were also evaluated for the photodegradation of methylene blue.« less

Modifying mesoporous silica nanoparticles to avoid the metabolic deactivation of 6-mercaptopurine and methotrexate in combinatorial chemotherapy.

PubMed

Wang, Wenjing; Fang, Chenjie; Wang, Xiaozhu; Chen, Yuxi; Wang, Yaonan; Feng, Wei; Yan, Chunhua; Zhao, Ming; Peng, Shiqi

2013-07-21

Mesoporous silica nanoparticles with amino and thiol groups (MSNSN) were prepared and covalently modified with methotrexate and 6-mercaptopurine to form 6-MP-MSNSN-MTX. In the presence of DTT, 6-MP-MSNSN-MTX gradually releases 6-MP. In rat plasma, 6-MP-MSNSN-MTX effectively inhibits the metabolic deactivation of 6-MP and MTX. 6-MP-MSNSN-MTX could be an agent for long-acting chemotherapy.

A novel reduced graphene oxide/molybdenum disulfide/polyaniline nanocomposite-based electrochemical aptasensor for detection of aflatoxin B1.

PubMed

Geleta, Girma Selale; Zhao, Zhen; Wang, Zhenxin

2018-03-26

In this study, we developed a novel reduced graphene oxide/molybdenum disulfide/polyaniline@gold nanoparticles-based electrochemical aptasensor (termed as RGO/MoS2/PANI@AuNPs/Apt) for detection of aflatoxin B1 (AFB1). The RGO/MoS2/PANI nanocomposites were synthesized and characterized by multiple techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). A glassy carbon electrode (GCE) was then modified by the RGO/MoS2/PANI nanocomposites, coated with a chitosan (Cs) film, and followed by AuNPs attachment for immobilizing the AFB1 aptamers. In the presence of AFB1, the AFB1 binding-induced conformation change of the immobilized aptamer on the electrode surface results in the reduction of the electron transfer from a [Fe(CN)6]3-/4- redox couple in the solution to the GCE surface. Therefore, the aptamer-AFB1 binding event can be easily monitored by the peak current change of the RGO/MoS2/PANI@AuNPs/Apt through differential pulse voltammetry (DPV) measurement. Under the optimized conditions, the as-developed RGO/MoS2/PANI@AuNPs/Apt exhibits a wide linear range from 0.01 fg mL-1 to 1.0 fg mL-1 and a remarkably low detection limit (3σ) of 0.002 fg mL-1. The aptasensor also has good reproducibility as well as shows high selectivity against other fungal toxins, such as OTA and FB1. Moreover, the practicability of the RGO/MoS2/PANI@AuNPs/Apt was demonstrated by the analysis of AFB1 in the spiked wine samples.

A soft approach to encapsulate sulfur: polyaniline nanotubes for lithium-sulfur batteries with long cycle life.

PubMed

Xiao, Lifen; Cao, Yuliang; Xiao, Jie; Schwenzer, Birgit; Engelhard, Mark H; Saraf, Laxmikant V; Nie, Zimin; Exarhos, Gregory J; Liu, Jun

2012-03-02

A novel vulcanized polyaniline nanotube/sulfur composite was prepared successfully via an in situ vulcanization process by heating a mixture of polyaniline nanotube and sulfur at 280 °C. The electrode could retain a discharge capacity of 837 mAh g(-1) after 100 cycles at a 0.1 C rate and manifested 76% capacity retention up to 500 cycles at a 1 C rate. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cadmium removal from simulated groundwater using alumina nanoparticles: behaviors and mechanisms.

PubMed

Koju, Neel Kamal; Song, Xin; Wang, Qing; Hu, Zhihao; Colombo, Claudio

2018-05-07

Cadmium (Cd), one of the most toxic contaminants in groundwater, can cause a severe threat to human health and ecological systems. In this study, alumina nanoparticles were synthesized and tested for high-efficiency Cd removal from simulated groundwater. Furthermore, the synthesized alumina nanoparticles were successfully modified using negatively charged glycerol, to alleviate the challenge of its low mobility in groundwater for the Cd removal. The maximum removal efficiency of both synthesized and glycerol-modified alumina nanoparticles were more than 99%. The sorption isotherm and kinetic data of both synthesized and glycerol-modified alumina nanoparticles were best fitted to the Freundlich model and the pseudo-second-order model, respectively, indicating that the sorption of Cd ions occurs on heterogeneous surfaces of both alumina nanoparticles via the chemisorption mechanism. X-ray photoelectron spectroscopy and energy dispersive X-ray analysis revealed the presence of Cd peak in both sorbents after contact with Cd. In addition, the FTIR analyses demonstrated that hydroxyl group participated in the sorption of Cd on both synthesized and glycerol-modified alumina nanoparticles, while other glycerol associated groups contributed to the removal of Cd ions by the glycerol-modified alumina nanoparticles. It was concluded that Cd removal by synthesized and glycerol-modified alumina nanoparticles were mainly due to ion exchange and electrostatic attraction, respectively. Desorption experiment suggested that both alumina nanoparticles are effective and practically significant sorbents to remediate Cd from contaminated groundwater. However, the stronger bond between Cd and glycerol-modified alumina, plus its potential of higher mobility due to the negative charge on the surface, warrant glycerol-modified alumina nanoparticles a better performance in remediating Cd contaminated groundwater than that of the synthesized alumina nanoparticles. Copyright © 2018 Elsevier

Flow injection amperometric detection of insulin at cobalt hydroxide nanoparticles modified carbon ceramic electrode.

PubMed

Habibi, Esmaeil; Omidinia, Eskandar; Heidari, Hassan; Fazli, Maryam

2016-02-15

Cobalt hydroxide nanoparticles were prepared onto a carbon ceramic electrode (CHN|CCE) using the cyclic voltammetry (CV) technique. The modified electrode was characterized by X-ray diffraction and scanning electron microscopy. The results showed that CHN with a single-layer structure was uniformly electrodeposited on the surface of CCE. The electrocatalytic activity of the modified electrode toward the oxidation of insulin was studied by CV. CHN|CCE was also used in a homemade flow injection analysis system for insulin determination. The limit of detection (signal/noise [S/N] = 3) and sensitivity were found to be 0.11 nM and 11.8 nA/nM, respectively. Moreover, the sensor was used for detection of insulin in human serum samples. This sensor showed attractive properties such as high stability, reproducibility, and high selectivity. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation and Application of Immobilized Surfactant-Modified PANi-CNT/TiO2 under Visible-Light Irradiation

PubMed Central

Yuan, Ching; Hung, Chung-Hsuang; Yuan, Chung-Shin; Li, Huei-Wen

2017-01-01

Hydrothermally and sol-gel-synthesized immobilized surfactant-modified polyaniline-carbon nanotubes/TiO2 (PANi-CNT/TiO2) photocatalysts were prepared and their application in the degradation of diethyl phthalate (DEP) under visible light at 410 nm was investigated in this sturdy. To improve the dispersion of nanoparticles and the transfer of electrons, the TiO2 surface was modified with both sodium dodecyl sulfate (SDS) and functionalized carbon nanotubes (CNT-COOH and CNT-COCl). With the addition of PANi, which was increased from 1–5%, the adsorption edge of the prepared photocatalysts shifted to 442 nm. The SDS linked the PANi polymers to achieve a thickness of coating of the film of up to 314–400 nm and 1301–1600 nm for sol-gel hydrolysis and hydrothermally-synthesized photocatalysts, respectively. An appropriate film thickness would extend the transfer path of the electrons and inhibit the recombination of the electrons and the electron-holes. The photo-degradation performance of DEP by the hydrothermally-synthesized photocatalysts was better than those by sol-gel hydrolysis. The results revealed that the hydroxyl radicals were the key oxidant in the degradation of DEP using hydrothermally-synthesized PANi-CNT/TiO2 photocatalysts. The morphology and functional groups of the raw materials of photocatalysts were characterized and a comparison of photocatalytic activity with other TiO2-based photocatalysts was also provided. PMID:28773238

Photocatalytic removal of polychlorinated biphenyls (PCBs) using carbon-modified titanium oxide nanoparticles

NASA Astrophysics Data System (ADS)

Shaban, Yasser A.; El Sayed, Mohamed A.; El Maradny, Amr A.; Al Farawati, Radwan Kh.; Al Zobidi, Mosa I.; Khan, Shahed U. M.

2016-03-01

In this work, the sonicated sol-gel method was used for synthesizing carbon-modified titanium oxide nanoparticles. Carbon incorporation was achieved by using titanium (IV) isopropoxide as a titanium and carbon-containing precursor. The photocatalytic efficiency of the synthesized photocatalyst was assessed by examining the photocatalytic removal of polychlorinated biphenyls (PCBs) from aqueous solution. For comparison, unmodified (regular) titanium dioxide (n-TiO2) was used as a reference catalyst. To confirm the carbon incorporation in CM-n-TiO2 nanoparticles, energy dispersive spectroscopy (EDS) analysis was used. Significantly, the bandgap energy was found to be reduced from 2.99 eV for n-TiO2 to 1.8 eV for CM-n-TiO2, which in turn improved the performance of CM-n-TiO2 toward the photocatalytic removal of PCBs. The effects of CM-n-TiO2 loading, PCBs concentration, and pH of the solution on the photodegradation rate of PCBs were investigated. The highest removal rate was found to be at pH 5 and CM-n-TiO2 loading of 0.5 g L-1. According to Langmuir-Hinshelwood model, the photodegradation of PCBs using CM-n-TiO2 followed a pseudo-first order reaction kinetics.

Galactose Derivative-Modified Nanoparticles for Efficient siRNA Delivery to Hepatocellular Carcinoma.

PubMed

Huang, Kuan-Wei; Lai, Yu-Tsung; Chern, Guann-Jen; Huang, Shao-Feng; Tsai, Chia-Lung; Sung, Yun-Chieh; Chiang, Cheng-Chin; Hwang, Pi-Bei; Ho, Ting-Lun; Huang, Rui-Lin; Shiue, Ting-Yun; Chen, Yunching; Wang, Sheng-Kai

2018-05-29

Successful siRNA therapy requires suitable delivery systems with targeting moieties such as small molecules, peptides, antibodies, or aptamers. Galactose (Gal) residues recognized by the asialoglycoprotein receptor (ASGPR) can serve as potent targeting moieties for hepatocellular carcinoma (HCC) cells. However, efficient targeting to HCC via galactose moieties rather than normal liver tissues in HCC patients remains a challenge. To achieve more efficient siRNA delivery in HCC, we synthesized various galactoside derivatives and investigated the siRNA delivery capability of nanoparticles modified with those galactoside derivatives. In this study, we assembled lipid/calcium/phosphate nanoparticles (LCP NPs) conjugated with eight types of galactoside derivatives and demonstrated that phenyl β-d-galactoside-decorated LCP NPs (L4-LCP NPs) exhibited a superior siRNA delivery into HCC cells compared to normal hepatocytes. VEGF siRNAs delivered by L4-LCP NPs downregulated VEGF expression in HCC in vitro and in vivo and led to a potent antiangiogenic effect in the tumor microenvironment of a murine orthotopic HCC model. The efficient delivery of VEGF siRNA by L4-LCP NPs that resulted in significant tumor regression indicates that phenyl galactoside could be a promising HCC-targeting ligand for therapeutic siRNA delivery to treat liver cancer.

Synthesis and characterization of intercalated polyaniline-clay nanocomposite using supercritical CO2

NASA Astrophysics Data System (ADS)

Abdelraheem, A.; El-Shazly, A. H.; Elkady, M. F.

2018-05-01

Lately, supercritical CO2 (SCCO2) have been getting great interest. It can be used in numerous applications because it is environmentally friendly, safe, comparatively low cost, and nonflammable. One of its applications is being a solvent in the synthesis of polymeric-clay nanocomposite. In this paper, intercalated polyaniline-clay nanocomposite (PANC) was prepared using SCCO2. The intercalation structure of polyaniline chains between clay layers was verified by various characterization techniques. Scanning electron microscope and transmission electron microscope (SEM-TEM) were used to show the morphology of the synthesized nanocomposite. The molecular structure of PANC nanocomposite was confirmed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The BET surface area and the conductivity of the nanocomposite were determined.

A Single Polyaniline Nanofiber Field Effect Transistor and Its Gas Sensing Mechanisms

PubMed Central

Chen, Dajing; Lei, Sheng; Chen, Yuquan

2011-01-01

A single polyaniline nanofiber field effect transistor (FET) gas sensor fabricated by means of electrospinning was investigated to understand its sensing mechanisms and optimize its performance. We studied the morphology, field effect characteristics and gas sensitivity of conductive nanofibers. The fibers showed Schottky and Ohmic contacts based on different electrode materials. Higher applied gate voltage contributes to an increase in gas sensitivity. The nanofiber transistor showed a 7% reversible resistance change to 1 ppm NH3 with 10 V gate voltage. The FET characteristics of the sensor when exposed to different gas concentrations indicate that adsorption of NH3 molecules reduces the carrier mobility in the polyaniline nanofiber. As such, nanofiber-based sensors could be promising for environmental and industrial applications. PMID:22163969

Enhanced physicochemical properties of chitosan/whey protein isolate composite film by sodium laurate-modified TiO2 nanoparticles.

PubMed

Zhang, Wei; Chen, Jiwang; Chen, Yue; Xia, Wenshui; Xiong, Youling L; Wang, Hongxun

2016-03-15

Chitosan/whey protein isolate film incorporated with sodium laurate-modified TiO2 nanoparticles was developed. The nanocomposite film was characterized by scanning electron microscopy, X-ray diffraction and differential scanning calorimetry, and investigated in physicochemical properties as color, tensile strength, elongation at break, water vapor permeability and water adsorption isotherm. Our results showed that the nanoparticles improved the compatibility of whey protein isolate and chitosan. Addition of nanoparticles increased the whiteness of chitosan/whey protein isolate film, but decreased its transparency. Compared with binary film, the tensile strength and elongation at break of nanocomposite film were increased by 11.51% and 12.01%, respectively, and water vapor permeability was decreased by 7.60%. The equilibrium moisture of nanocomposite film was lower than binary film, and its water sorption isotherm of the nanocomposite film fitted well to Guggenheim-Anderson-deBoer model. The findings contributed to the development of novel food packaging materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mesquite Gum as a Novel Reducing and Stabilizing Agent for Modified Tollens Synthesis of Highly Concentrated Ag Nanoparticles

PubMed Central

Moreno-Trejo, Maira Berenice; Sánchez-Domínguez, Margarita

2016-01-01

The synthesis that is described in this study is for the preparation of silver nanoparticles of sizes ranging from 10 nm to 30 nm with a defined shape (globular), confirmed by UV-vis, SEM, STEM and DLS analysis. This simple and favorable one-step modified Tollens reaction does not require any special equipment or other stabilizing or reducing agent except for a solution of purified mesquite gum, and it produces aqueous colloidal dispersions of silver nanoparticles with a stability that exceeds three months, a relatively narrow size distribution, a low tendency to aggregate and a yield of at least 95% for all cases. Reaction times are between 15 min and 60 min to obtain silver nanoparticles in concentrations ranging from 0.1 g to 3 g of Ag per 100 g of reaction mixture. The proposed synthetic method presents a high potential for scale-up, since its production capacity is rather high and the methodology is simple. PMID:28773938

A systems approach to designing next generation vaccines: combining α-galactose modified antigens with nanoparticle platforms

NASA Astrophysics Data System (ADS)

Phanse, Yashdeep; Carrillo-Conde, Brenda R.; Ramer-Tait, Amanda E.; Broderick, Scott; Kong, Chang Sun; Rajan, Krishna; Flick, Ramon; Mandell, Robert B.; Narasimhan, Balaji; Wannemuehler, Michael J.

2014-01-01

Innovative vaccine platforms are needed to develop effective countermeasures against emerging and re-emerging diseases. These platforms should direct antigen internalization by antigen presenting cells and promote immunogenic responses. This work describes an innovative systems approach combining two novel platforms, αGalactose (αGal)-modification of antigens and amphiphilic polyanhydride nanoparticles as vaccine delivery vehicles, to rationally design vaccine formulations. Regimens comprising soluble αGal-modified antigen and nanoparticle-encapsulated unmodified antigen induced a high titer, high avidity antibody response with broader epitope recognition of antigenic peptides than other regimen. Proliferation of antigen-specific CD4+ T cells was also enhanced compared to a traditional adjuvant. Combining the technology platforms and augmenting immune response studies with peptide arrays and informatics analysis provides a new paradigm for rational, systems-based design of next generation vaccine platforms against emerging and re-emerging pathogens.

Determination of anionic surface active agents using silica coated magnetite nanoparticles modified with cationic surfactant aggregates.

PubMed

Pena-Pereira, Francisco; Duarte, Regina M B O; Trindade, Tito; Duarte, Armando C

2013-07-19

The development of a novel methodology for extraction and preconcentration of the most commonly used anionic surface active agents (SAAs), linear alkylbenzene sulfonates (LAS), is presented herein. The present method, based on the use of silica-magnetite nanoparticles modified with cationic surfactant aggregates, was developed for determination of C10-C13 LAS homologues. The proposed methodology allowed quantitative recoveries of C10-C13 LAS homologues by using a reduced amount of magnetic nanoparticles. Limits of detection were in the range 0.8-1.9μgL(-1) for C10-C13 LAS homologues, while the repeatability, expressed as relative standard deviation (RSD), ranged from 2.0 to 3.9% (N=6). Finally, the proposed method was successfully applied to the analysis of a variety of natural water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Dielectric loss property of strong acids doped polyaniline (PANi)

NASA Astrophysics Data System (ADS)

Amalia, Rianti; Hafizah, Mas Ayu Elita; Andreas, Manaf, Azwar

2018-04-01

In this study, strong acid doped polyaniline (PANi) has been successfully fabricated through the chemical oxidative polymerization process with various polymerization times. Nonconducting PANi resulting from the polymerization process at various polymerization times were then doped by a strong acid HClO4 to generate dielectric properties. Ammonium Persulfate (APS) as an initiator was used during Polymerization process to develop dark green precipitates which then called Emeraldine Base Polyaniline (PANi-EB). The PANi-EB was successively doped by strong acid HClO4 with dopant and PANi ratio 10:1 to enhance the electrical conductivity. The conductivity of doped PANi was evaluated by Four Point Probe. Results of evaluation showed that the conductivity values of HClO4 doped PANi were in the range 337-363 mS/cm. The dielectric properties of doped PANi were evaluated by Vector Network Analyzer (VNA) which suggested that an increase in the permittivity value in the conducting PANi. It is concluded that PANi could be a potential candidate for electromagnetic waves absorbing materials.

Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

PubMed Central

Das, Gautam; Yoon, Hyon Hee

2015-01-01

An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm−2·mM−1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. PMID:26346240

Nanoparticle-based biosensor for the detection of emerging pandemic influenza strains.

PubMed

Kamikawa, Tracy L; Mikolajczyk, Malgorzata G; Kennedy, Michael; Zhang, Pei; Wang, Wei; Scott, Dorothy E; Alocilja, Evangelyn C

2010-12-15

Electrically active magnetic (EAM) nanoparticles, consisting of aniline monomer polymerized around gamma iron(III) oxide (γ-Fe(2)O(3)) cores, serve as the basis of a direct-charge transfer biosensor developed for detection of surface glycoprotein hemagglutinin (HA) from the Influenza A virus (FLUAV) H5N1 (A/Vietnam/1203/04). H5N1 preferentially binds α2,3-linked host glycan receptors. EAM nanoparticles were immunofunctionalized with antibodies against target HA. Glycans preincubated with HA in 10% mouse serum were incubated with anti-HA-EAM complexes. The anti-HA-EAM complexes effectively acted as immunomagnetic separator of HA from mouse serum matrix. EAM nanoparticles served as the biosensor transducer for cyclic voltammetry measurements. The polyaniline was made electrically active by hydrochloric acid doping. Experimental results indicate that the biosensor is able to detect recombinant H5 HA at 1.4 μM in 10% mouse serum, with high specificity for H5 as compared to H1 (H1N1 A/South Carolina/1/18). This novel design applies EAM nanoparticles in a sensitive, specific, affordable, and easy-to-use biosensor with applications in disease monitoring and biosecurity. Copyright © 2010 Elsevier B.V. All rights reserved.

Modified ferrite core-shell nanoparticles magneto-structural characterization

NASA Astrophysics Data System (ADS)

Klekotka, Urszula; Piotrowska, Beata; Satuła, Dariusz; Kalska-Szostko, Beata

2018-06-01

In this study, ferrite nanoparticles with core-shell structures and different chemical compositions of both the core and shell were prepared with success. Proposed nanoparticles have in the first and second series magnetite core, and the shell is composed of a mixture of ferrites with Fe3+, Fe2+ and M ions (where M = Co2+, Mn2+ or Ni2+) with a general composition of M0.5Fe2.5O4. In the third series, the composition is inverted, the core is composed of a mixture of ferrites and as a shell magnetite is placed. Morphology and structural characterization of nanoparticles were done using Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and Infrared spectroscopy (IR). While room temperature magnetic properties were measured using Mössbauer spectroscopy (MS). It is seen from Mössbauer measurements that Co always increases hyperfine magnetic field on Fe atoms at RT, while Ni and Mn have opposite influences in comparison to pure Fe ferrite, regardless of the nanoparticles structure.

Fabrication of free-standing hierarchical carbon nanofiber/graphene oxide/polyaniline films for supercapacitors.

PubMed

Xu, Dongdong; Xu, Qun; Wang, Kaixi; Chen, Jun; Chen, Zhimin

2014-01-08

A hierarchical high-performance electrode with nanoacanthine-style polyaniline (PANI) deposited onto a carbon nanofiber/graphene oxide (CNF/GO) template was successfully prepared via an in situ polymerization process. The morphology analysis shows that introducing one-dimensional (1D) CNF could significantly decrease/inhibit the staking of laminated GO to form an open-porous CNF/GO architecture. Followed with in situ facial deposition of PANI, the as-synthesized PANI modified CNF/GO exhibits three-dimensional (3D) hierarchical layered nanoarchitecture, which favors the diffusion of the electrolyte ions into the inner region of active materials. The hierarchical free-standing electrodes were directly fabricated into sandwich structured supercapacitors using 1 M H2SO4 as the electrolyte showing a significant specific capacitance of 450.2 F/g at the voltage scan rate of 10 mV/s. The electrochemical properties of the hierarchical structure can be further improved by a reduction procedure of GO before the deposition of PANI.

Strong and Robust Polyaniline-Based Supramolecular Hydrogels for Flexible Supercapacitors.

PubMed

Li, Wanwan; Gao, Fengxian; Wang, Xiaoqian; Zhang, Ning; Ma, Mingming

2016-08-01

We report a supramolecular strategy to prepare conductive hydrogels with outstanding mechanical and electrochemical properties, which are utilized for flexible solid-state supercapacitors (SCs) with high performance. The supramolecular assembly of polyaniline and polyvinyl alcohol through dynamic boronate bond yields the polyaniline-polyvinyl alcohol hydrogel (PPH), which shows remarkable tensile strength (5.3 MPa) and electrochemical capacitance (928 F g(-1) ). The flexible solid-state supercapacitor based on PPH provides a large capacitance (306 mF cm(-2) and 153 F g(-1) ) and a high energy density of 13.6 Wh kg(-1) , superior to other flexible supercapacitors. The robustness of the PPH-based supercapacitor is demonstrated by the 100 % capacitance retention after 1000 mechanical folding cycles, and the 90 % capacitance retention after 1000 galvanostatic charge-discharge cycles. The high activity and robustness enable the PPH-based supercapacitor as a promising power device for flexible electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of QCM Trimethylamine Sensor Based on Water Soluble Polyaniline.

PubMed

Li, Guang; Zheng, Junbao; Ma, Xingfa; Sun, Yu; Fu, Jun; Wu, Gang

2007-10-17

A rapid, sensitive, low-cost device to detect trimethylamine was presented in thispaper. The preparation of water soluble polyaniline was firstly studied. Then the polyanilinewas characterized via Fourier transform infrared spectroscopy (FTIR), UV-visiblespectroscopy and scanning electron microscopy (SEM). Based on the water solublepolyaniline film, a quartz crystal microbalance (QCM) sensor for trimethylamine detectionwas fabricated and its characteristics were examined. The sensor consisted of one quartzcrystal oscillator coated with the polyaniline film for sensing and the other one forreference. Pretreated with trimethylamine, the QCM sensor had an excellent linearsensitivity to trimethylamine. Easily recovered by N2 purgation, the response of the sensorexhibited a good repeatability. Responses of the sensor to trimethylamine, ethanol and ethylacetate were compared, and the results showed that the response was related to the polarityof the analyte vapor. Experimental result also showed that the sensitivity of the sensor wasrelatively stable within one month. The simple and feasible method to prepare and coat thepolyaniline sensing film makes it promising for mass production.

Novel ammonia sensor based on polyaniline/polylactic acid composite films

NASA Astrophysics Data System (ADS)

Sotirov, S.; Bodurov, I.; Marudova, M.

2017-01-01

We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al2O3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected.

Poloxamer surface modified trimethyl chitosan nanoparticles for the effective delivery of methotrexate in osteosarcoma.

PubMed

Li, Shenglong; Xiong, Yuyuan; Zhang, Xiaojing

2017-06-01

The present work is an effort to explore the poloxamer-modified trimethyl chitosan (TMC) encapsulated MTX for osteosarcoma treatment in order to improve the therapeutic efficacy and minimize severe toxicity associated with the clinical usage of MTX. The methotrexate-loaded pluronic-chitosan nanoparticles (MTCN) was nanosized and exhibited a controlled release of drug from the carrier system. The MTCN showed higher accumulation in cell cytoplasm region evident by the high red fluorescence indicating its uptake through energy-dependent endocytosis process. MTCN exhibited the increased cytotoxicity in MG63 cells compared free MTX due to its enhanced cellular uptake. Especially, MTCN exhibited a superior apoptosis effect with bright chromatin condensation and nuclear fragmentation was observed and showed remarkably higher apoptosis (∼48%) compared to that of free drug. The results of this investigation clearly demonstrate that the poloxamer-modified trimethyl chitosan (TMC) seems to have a great potential as a drug carrier in cancer chemotherapy. The present research work offers immense scope for further exploitation of poloxamer-modified trimethyl chitosan (TMC) in future for the development of nanoparticulate drug delivery system for cancer chemotherapy. Copyright © 2017. Published by Elsevier Masson SAS.

Facile preparation of multifunctional carbon nanotube/magnetite/polyaniline nanocomposite offering a strong option for efficient solid-phase microextraction coupled with GC-MS for the analysis of phenolic compounds.

PubMed

Tafazoli, Zahra; Azar, Parviz Aberoomand; Tehrani, Mohammad Saber; Husain, Syed Waqif

2018-04-20

The aim of this study the synthesis of a highly efficient organic-inorganic nanocomposite. In this research, the carbon nanotube/magnetite/polyaniline nanocomposite was successfully prepared through a facile route. Monodisperse magnetite nanospheres were prepared through the coprecipitation route, and polyaniline nanolayer as a modified shell with a high surface area was synthesized by an in situ growth route and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The prepared nanocomposite was immobilized on a stainless-steel wire for the fabrication of the solid-phase microextraction fiber. The combination of headspace solid-phase microextraction using carbon nanotube/magnetite/polyaniline nanocomposite fiber with gas chromatography and mass spectrometry can achieve a low limit of detection and can be applied to determine phenolic compounds in water samples. The effects of the extraction and desorption parameters including extraction temperature and time, ionic strength, stirring rate, pH, and desorption temperature and time have been studied. Under the optimum conditions, the dynamic linear range was 0.01-500 ng mL -1 and the limits of detection of phenol, 4-chlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol were the lowest (0.008 ng mL -1 ) for three times. The coefficient of determination of all calibration curves was more than 0.990. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

ROOM TEMPERATURE BULK AND TEMPLATE-FREE SYNTHESIS OF LEUCOEMARLDINE POLYANILINE NANOFIBERS

EPA Science Inventory

Herein, we describe a simple strategy for the bulk and template-free synthesis of reduced leucoemarldine polyaniline nanofibers size ranging from as low as 10 nm to 50 nm without the use of any reducing agents at room temperature.

Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

NASA Astrophysics Data System (ADS)

Kandeva, M.; Grozdanova, T.; Karastoyanov, D.; Assenova, E.

2017-02-01

The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.

Facile Preparation of a Platinum Silicide Nanoparticle-Modified Tip Apex for Scanning Kelvin Probe Microscopy.

PubMed

Lin, Chun-Ting; Chen, Yu-Wei; Su, James; Wu, Chien-Ting; Hsiao, Chien-Nan; Shiao, Ming-Hua; Chang, Mao-Nan

2015-12-01

In this study, we propose an ultra-facile approach to prepare a platinum silicide nanoparticle-modified tip apex (PSM tip) used for scanning Kelvin probe microscopy (SKPM). We combined a localized fluoride-assisted galvanic replacement reaction (LFAGRR) and atmospheric microwave annealing (AMA) to deposit a single platinum silicide nanoparticle with a diameter of 32 nm on the apex of a bare silicon tip of atomic force microscopy (AFM). The total process was completed in an ambient environment in less than 3 min. The improved potential resolution in the SKPM measurement was verified. Moreover, the resolution of the topography is comparable to that of a bare silicon tip. In addition, the negative charges found on the PSM tips suggest the possibility of exploring the use of current PSM tips to sense electric fields more precisely. The ultra-fast and cost-effective preparation of the PSM tips provides a new direction for the preparation of functional tips for scanning probe microscopy.

Fabrication of free-standing, electrochemically active, and biocompatible graphene oxide-polyaniline and graphene-polyaniline hybrid papers.

PubMed

Yan, Xingbin; Chen, Jiangtao; Yang, Jie; Xue, Qunji; Miele, Philippe

2010-09-01

In this work, we report a low-cost technique via simple rapid-mixture polymerization of aniline using graphene oxide (GO) and graphene papers as substrates, respectively, to fabricate free-standing, flexible GO-polyaniline (PANI) and graphene-PANI hybrid papers. The morphology and microstructure of the obtained papers were characterized by FESEM, FTIR, Raman, and XRD. As results, nanostructural PANI can be deposited on the surfaces of GO and graphene papers, forming thin, lightweight, and flexible paperlike hybrid papers. The hybrid papers display a remarkable combination of excellent electrochemical performances and biocompatibility, making the paperlike materials attractive for new kinds of applications in biosciences.

Controllable synthesis of organic-inorganic hybrid MoOx/polyaniline nanowires and nanotubes.

PubMed

Wang, Sinong; Gao, Qingsheng; Zhang, Yahong; Gao, Jing; Sun, Xuhui; Tang, Yi

2011-02-01

A novel chemical oxidative polymerization approach has been proposed for the controllable preparation of organic-inorganic hybrid MoO(x)/polyaniline (PANI) nanocomposites based on the nanowire precursor of Mo(3)O(10)(C(6)H(8)N)(2)·2H(2)O with sub-nanometer periodic structures. The nanotubes, nanowires, and rambutan-like nanoparticles of MoO(x)/PANI were successfully obtained through simply modulating the pH values to 2.5-3.5, ≈2.0 and ≈1.0, respectively. Through systematic physicochemical characterization, such as scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and so forth, the composition and structure of MoO(x)/PANI hybrid nanocomposites are well confirmed. It is found that the nanowire morphology of the precursor is the key to achieve the one-dimensional (1D) structures of final products. A new polymerization-dissolution mechanism is proposed to explain the formation of such products with different morphologies, in which the match between polymerization and dissolution processes of the precursor plays the important role. This approach will find a new way to controllably prepare various organic-inorganic hybrid 1D nanomaterials especially for polymer-hybrid nanostructures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasmonic gold nanoparticles modified titania nanotubes for antibacterial application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jinhua; Zhou, Huaijuan; Qian, Shi

Close-packed TiO{sub 2} nanotube arrays are prepared on metallic Ti surface by electrochemical anodization. Subsequently, by magnetron sputtering, Au nanoparticles are coated onto the top sidewall and tube inwall. The Au@TiO{sub 2} systems can effectively kill Staphylococcus aureus and Escherichia coli in darkness due to the existence of Au nanoparticles. On the basis of classical optical theories, the antibacterial mechanism is proposed from the perspective of localized surface plasmon resonance. Respiratory electrons of bacterial membrane transfer to Au nanoparticles and then to TiO{sub 2}, which makes bacteria steadily lose electrons until death. This work provides insights for the better understandingmore » and designing of noble metal nanoparticles-based plasmonic heterostructures for antibacterial application.« less