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  Subjects -> CHEMISTRY (Total: 762 journals)
    - ANALYTICAL CHEMISTRY (45 journals)
    - CHEMISTRY (527 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (24 journals)
    - INORGANIC CHEMISTRY (40 journals)
    - ORGANIC CHEMISTRY (40 journals)
    - PHYSICAL CHEMISTRY (64 journals)

CHEMISTRY (527 journals)                  1 2 3 4 5 6 | Last

Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (30 followers)
ACS Catalysis     Full-text available via subscription   (21 followers)
ACS Chemical Neuroscience     Full-text available via subscription   (10 followers)
ACS Combinatorial Science     Full-text available via subscription   (6 followers)
ACS Macro Letters     Full-text available via subscription   (16 followers)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (16 followers)
ACS Nano     Full-text available via subscription   (154 followers)
ACS Photonics     Full-text available via subscription   (1 follower)
ACS Synthetic Biology     Full-text available via subscription   (7 followers)
Acta Chemica Iasi     Open Access  
Acta Chimica Slovaca     Open Access   (5 followers)
Acta Chromatographica     Full-text available via subscription   (9 followers)
Acta Facultatis Medicae Naissensis     Open Access   (1 follower)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (2 followers)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (1 follower)
Adhesion Adhesives & Sealants     Hybrid Journal   (3 followers)
Adsorption Science & Technology     Full-text available via subscription   (5 followers)
Advanced Functional Materials     Hybrid Journal   (29 followers)
Advances in Chemical Engineering and Science     Open Access   (19 followers)
Advances in Chemical Science     Open Access   (6 followers)
Advances in Colloid and Interface Science     Full-text available via subscription   (12 followers)
Advances in Drug Research     Full-text available via subscription   (13 followers)
Advances in Fluorine Science     Full-text available via subscription   (6 followers)
Advances in Fuel Cells     Full-text available via subscription   (10 followers)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (6 followers)
Advances in Materials Physics and Chemistry     Open Access   (7 followers)
Advances in Nanoparticles     Open Access   (9 followers)
Advances in Organometallic Chemistry     Full-text available via subscription   (7 followers)
Advances in Polymer Science     Hybrid Journal   (35 followers)
Advances in Protein Chemistry     Full-text available via subscription   (4 followers)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (8 followers)
Advances in Quantum Chemistry     Full-text available via subscription   (3 followers)
African Journal of Chemical Education     Open Access  
African Journal of Pure and Applied Chemistry     Open Access  
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access  
Agrokémia és Talajtan     Full-text available via subscription   (2 followers)
Alchemy     Open Access   (2 followers)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (3 followers)
AMB Express     Open Access   (1 follower)
Ambix     Hybrid Journal   (3 followers)
American Journal of Applied Sciences     Open Access   (27 followers)
American Journal of Biochemistry and Biotechnology     Open Access   (79 followers)
American Journal of Biochemistry and Molecular Biology     Open Access   (7 followers)
American Journal of Chemistry     Open Access   (14 followers)
American Journal of Plant Physiology     Open Access   (9 followers)
American Mineralogist     Full-text available via subscription   (2 followers)
Analyst     Full-text available via subscription   (33 followers)
Angewandte Chemie     Hybrid Journal   (12 followers)
Angewandte Chemie International Edition     Hybrid Journal   (142 followers)
Annales UMCS, Chemia     Open Access   (2 followers)
Annual Reports in Computational Chemistry     Full-text available via subscription   (1 follower)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (2 followers)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (4 followers)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (8 followers)
Annual Review of Food Science and Technology     Full-text available via subscription   (11 followers)
Anti-Infective Agents     Hybrid Journal   (1 follower)
Applied Organometallic Chemistry     Hybrid Journal   (3 followers)
Applied Spectroscopy     Full-text available via subscription   (11 followers)
Applied Surface Science     Hybrid Journal   (13 followers)
Arabian Journal of Chemistry     Full-text available via subscription   (5 followers)
ARKIVOC     Open Access   (1 follower)
Asian Journal of Biochemistry     Open Access   (1 follower)
Australian Journal of Chemistry     Hybrid Journal   (4 followers)
Autophagy     Full-text available via subscription  
Avances en Quimica     Open Access   (1 follower)
Biocell     Open Access  
Biochemical Pharmacology     Hybrid Journal   (5 followers)
Biochemistry     Full-text available via subscription   (120 followers)
Biochemistry Insights     Open Access   (3 followers)
Biochemistry Research International     Open Access   (3 followers)
BioChip Journal     Hybrid Journal   (1 follower)
Bioinorganic Chemistry and Applications     Open Access   (4 followers)
Biointerface Research in Applied Chemistry     Open Access   (1 follower)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (16 followers)
Biomass Conversion and Biorefinery     Partially Free   (5 followers)
Biomedical Chromatography     Hybrid Journal   (7 followers)
Biomolecular NMR Assignments     Hybrid Journal   (2 followers)
BioNanoScience     Partially Free   (4 followers)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (26 followers)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (20 followers)
Bioorganic Chemistry     Hybrid Journal   (5 followers)
Biopolymers     Hybrid Journal   (12 followers)
Biosensors     Open Access   (3 followers)
Biotechnic and Histochemistry     Hybrid Journal   (1 follower)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (1 follower)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (11 followers)
Canadian Association of Radiologists Journal     Full-text available via subscription   (3 followers)
Canadian Journal of Chemistry     Full-text available via subscription   (6 followers)
Canadian Mineralogist     Full-text available via subscription   (1 follower)
Carbohydrate Research     Hybrid Journal   (10 followers)
Carbon     Hybrid Journal   (33 followers)
Catalysis for Sustainable Energy     Open Access   (1 follower)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (3 followers)
Catalysis Science and Technology     Free   (3 followers)
Catalysis Surveys from Asia     Hybrid Journal   (3 followers)
Catalysts     Open Access   (5 followers)
Cellulose     Hybrid Journal   (4 followers)
Central European Journal of Chemistry     Hybrid Journal   (5 followers)

        1 2 3 4 5 6 | Last

Advanced Functional Materials    [31 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1616-301X - ISSN (Online) 1616-3028
     Published by John Wiley and Sons Homepage  [1594 journals]   [SJR: 4.862]   [H-I: 136]
  • Ultrasensitive Telomerase Activity Detection in Circulating Tumor Cells
           Based on DNA Metallization and Sharp Solid‐State Electrochemical
           Techniques
    • Authors: Li Wu; Jiasi Wang, Jinsong Ren, Xiaogang Qu
      Pages: n/a - n/a
      Abstract: Being considered a “liquid biopsy”, circulating tumor cell (CTC) quantification is of great interest for evaluating cancer dissemination, predicting patient prognosis, and also for the evaluation of therapeutic treatments, representing a reliable potential alternative to invasive biopsies and subsequent proteomic and functional genetic analysis. Compared to a biopsy, the gold standard of current cancer diagnosis, an important characteristic of a blood test is that it is safe and can be performed at many points during the disease, allowing the development of appropriate therapy modifications and potentially improving patient's quality of life. In this work, an ultrasensitive electrochemical telomerase activity‐sensing strategy is presented that utilizes DNA‐templated deposition of silver nanoparticles as electroactive labels through a highly sharp solid‐state Ag/AgCl reaction with DNA exonuclease III‐assisted background current suppression. This nanoparticle‐mediated signal amplification resulted in significantly decreased detection limit, which is better than the vast majority of reported methods and achieves a sensitivity comparable to the conventional telomeric repeat amplification protocol (TRAP). This work may pave a new PCR‐free way for the detection of telomerase activity in CTCs via a noninvasive routine blood test for point‐of‐care diagnosis and individualized treatment of cancer. Telomerase detection in circulating tumor cells (CTCs): On the basis of enzyme‐assisted background‐noise suppression and DNA metallization‐based signal amplification, the constructed biosensor shows ultrahigh sensitivity for telomerase detection. This work paves the way for a new PCR‐free method for measuring telomerase activity in CTCs, and point‐of‐care diagnosis and individualized treatment of cancers via a noninvasive routine blood test.
      PubDate: 2014-01-23T13:40:59.132067-05:
      DOI: 10.1002/adfm.201303818
       
  • DyeIonogels: Proton‐Responsive Ionogels Based on a Dye‐Ionic
           Liquid Exhibiting Reversible Color Change
    • Authors: Zai‐Lai Xie; Xing Huang, Andreas Taubert
      Pages: n/a - n/a
      Abstract: Transparent, ion‐conducting, and flexible ionogels based on the room temperature ionic liquid (IL) 1‐butyl‐3‐methylimidazolium bis(trifluoromethane sulfonyl)imide [Bmim][N(Tf)2], the dye‐IL (DIL) 1‐butyl‐3‐methylimidazolium methyl orange [Bmim][MO], and poly(methylmethacrylate) (PMMA) are prepared. Upon IL incorporation the thermal stability of the PMMA matrix significantly increases from 220 to 280 °C. The ionogels have a relatively high ionic conductivity of 10−4 S cm−1 at 373 K. Most importantly, the ionogels exhibit a strong and reversible color change when exposed to aqueous or organic solutions containing protons or hydroxide ions. The resulting material is thus a prototype of soft multifunctional matter featuring ionic conductivity, easy processability, response to changes in the environment, and a strong readout signal, the color change, that could be used in optical data storage or environmental sensing. The combination of the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium bis(trifluoromethane sulfonyl)imide, a dye‐IL (DIL, 1‐butyl‐3‐methylimidazolium methyl orange), and poly(methylmethacrylate) (PMMA) yields transparent, ion‐conducting, and flexible ionogels with a strong and reversible color change when acidic or basic environments. The ionogels are prototypes of soft multifunctional matter featuring a strong readout signal, the color change, that could be used in optical data storage or environmental sensing.
      PubDate: 2014-01-23T13:40:53.850287-05:
      DOI: 10.1002/adfm.201303016
       
  • Molecular Packing‐Induced Transition between Ambipolar and Unipolar
           Behavior in Dithiophene‐4,9‐dione‐Containing Organic
           Semiconductors
    • Authors: Huan Xu; Ye‐Cheng Zhou, Xing‐Yu Zhou, Ke Liu, Lu‐Ya Cao, Yong Ai, Zhi‐Ping Fan, Hao‐Li Zhang
      Pages: n/a - n/a
      Abstract: By changing the packing motif of the conjugated cores and the thin‐film microstructures, unipolar organic semiconductors may be converted into ambipolar materials. A combined experimental and theoretical investigation is conducted on the thin‐film organic field‐effect transistors (OFETs) of three organic semiconductors that have the same conjugated core structure of s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐4,9‐dione but with different n‐alkyl groups. The optical and electrochemical measurements suggest that the three organic semiconductors have very similar energy levels; however, their OFETs exhibit dramatically different transport characteristics. Transistors based on compound 1a or 1c show ambipolar transport properties, while those based on compound 1b show p‐type unipolar behavior. Specifically, compound 1c is characterized as a good ambipolar semiconductor with the highest electron mobility of 0.22 cm2 V−1 s−1 and the highest hole mobility of 0.03 cm2 V−1 s−1. Complementary metal oxide semiconductor (CMOS) inverters incorporated with compound 1c show sharp inversions with high gains above 50. Theoretical investigations reveal that the drastic difference in the transport properties of the three materials is due to the difference in their molecular packing and film microstructures. Organic semiconductor materials with the same conjugated core can exhibit either unipolar or ambipolar transport behavior in thin‐film transistors. Experimental and theoretical investigations reveal that the drastic differences in transport properties are due to their different molecular packing and thin‐film structures induced by the different alkyl substitutes.
      PubDate: 2014-01-23T13:40:46.653433-05:
      DOI: 10.1002/adfm.201302855
       
  • Micropattern Formation by Molecular Migration via UV‐induced
           Dehydration of Block Copolymers
    • Authors: Kenji Okada; Yasuaki Tokudome, Rie Makiura, Kristina Konstas, Luca Malfatti, Plinio Innocenzi, Hiroki Ogawa, Toshiji Kanaya, Paolo Falcaro, Masahide Takahashi
      Pages: n/a - n/a
      Abstract: A novel UV lithographic technique for the patterning of the block copolymer (Pluronic) thin films is developed. The present method is based on UV‐induced water affinity changes in block copolymer films. By water vapor post‐treatment of the film, a difference in water content is established between UV illuminated and unilluminated sections, which can induce an osmotic pressure at the interface. This osmotic pressure drives the migration of Pluronic molecules, resulting in formation of patterns on the block copolymer films. Remarkably, this patterning method requires neither initiators nor polymerizable moieties which are essential for a conventional photolithographic approach. Additionally, the etching process is bypassed, eliminating the use of destructive acids or organic solvents and making this an environmentally friendly patterning protocol. It is reported that Pluronic is photo‐responsive to UV exposure, which causes the dehydration of the PEO‐PPO‐PEO backbone. A novel UV‐induced fabrication of nano/macro hierarchical structures of triblock copolymer lamellar films is developed. The method is based on a change in the water affinity of the films activated by UV light. Osmotic pressure at the interface between illuminated and unilluminated parts drives the molecular migration for surface pattern formation. This remarkable advantage makes this method exceptionally versatile.
      PubDate: 2014-01-23T13:40:31.791227-05:
      DOI: 10.1002/adfm.201302812
       
  • Reversible Disorder in a Room Temperature Ferromagnet
    • Authors: Spencer L. Tomarken; Daniel M. Silevitch, Gabriel Aeppli, Braden A.W. Brinkman, Jian Xu, Karin A. Dahmen, Thomas F. Rosenbaum
      Pages: n/a - n/a
      Abstract: Random magnetic fields, varying from site to site in a magnetic material, are a form of disorder that can determine the local architecture and stability of the magnetic state. In a ferromagnet, the application of an external magnetic field can amplify the effects of the internal random fields and, in principle, harden a magnetic domain, without changing temperature and only for as long as the external field is present. Here, the rare‐earth compound Nd2Fe14B, formed with a granular morphology of random‐packed, elongated grains, is an experimental realization of the Random Field Ising Model in a room temperature ferromagnet. The application of magnetic fields transverse to the easy axis tunes the coupling between the structural disorder and the magnetic pinning properties. This material both illuminates the intricacies of tunable disorder and serves as a guidepost along the way to developing increased‐density magnetic storage media. Application of a transverse magnetic field can reversibly tune the magnetic hardness of a disordered uniaxial, high anisotropy rare earth magnet at room temperature. Random field effects control the effective strength of the material's intrinsic disorder, providing a convenient control knob for rapidly and isothermally switching between different computationally relevant magnetic characteristics.
      PubDate: 2014-01-23T13:36:03.10639-05:0
      DOI: 10.1002/adfm.201303231
       
  • Masthead: (Adv. Funct. Mater. 4/2014)
    • Pages: n/a - n/a
      PubDate: 2014-01-23T08:17:11.356318-05:
      DOI: 10.1002/adfm.201470024
       
  • Increase Output Energy and Operation Frequency of a Triboelectric
           Nanogenerator by Two Grounded Electrodes Approach
    • Authors: Gang Cheng; Zong‐Hong Lin, Zuliang Du, Zhong Lin Wang
      Pages: n/a - n/a
      Abstract: Triboelectric nanogenerator (TENG) generally operates using two‐electrodes to form a closed outer circuit loop without directly contacting ground. Here, a newly designed TENG, the two electrodes of which are grounded for doubling the energy output and the operation frequency, is introduced. The TENG operates in two modes: two‐channel mode in which the two electrodes are simultaneously connected to the ground, and single‐channel mode in which the two electrodes are alternately connected to the ground through a self‐triggered vibrating switch. Both modes doubles the total charges to be transported compared to the traditional ungrounded TENG. For the single‐channel TENG, about 30 current peaks with an output frequency of 50 Hz are generated in a single cycle at a motion triggering frequency of 2 Hz. The output energy at a load lower than 10 MΩ of the single‐channel TENG is enhanced, and the enhancing ratio is more than 100 at a load of 100 kΩ. The two electrodes grounded TENG provides a new strategy for effective use of the energy harvested from our living environment. The two‐electrodes‐grounded triboelectric nanogenerator (TEG‐TENG) is developed. The TEG‐TENG can double the generated charges and enhance the output frequency compared to the traditional non‐grounded TENG. The output energy at a load lower than 10 MΩ is also enhanced, and the enhanced ratio is more than 100 at a load of 100 kΩ.
      PubDate: 2014-01-22T13:29:40.653576-05:
      DOI: 10.1002/adfm.201303659
       
  • Near‐Infrared Light Photovoltaic Detector Based on GaAs Nanocone
           Array/Monolayer Graphene Schottky Junction
    • Authors: Lin‐Bao Luo; Jing‐Jing Chen, Ming‐Zheng Wang, Han Hu, Chun‐Yan Wu, Qiang Li, Li Wang, Jian‐An Huang, Feng‐Xia Liang
      Pages: n/a - n/a
      Abstract: Near infrared light photodiodes have been attracting increasing research interest due to their wide application in various fields. In this study, the fabrication of a new n‐type GaAs nanocone (GaAsNCs) array/monolayer graphene (MLG) Schottky junction is reported for NIR light detection. The NIR photodetector (NIRPD) shows obvious rectifying behavior with a turn‐on voltage of 0.6 V. Further device analysis reveals that the photovoltaic NIRPDs are highly sensitive to 850 nm light illumination, with a fast response speed and good spectral selectivity at zero bias voltage. It is also revealed that the NIRPD is capable of monitoring high‐switching frequency optical signals (∼2000 Hz) with a high relative balance. Theoretical simulations based on finite difference time domain (FDTD) analysis finds that the high device performance is partially associated with the optical property, which can trap most incident photons in an efficient way. It is expected that such a self‐driven NIRPD will have potential application in future optoelectronic devices. A new Schottky junction near‐infrared light photodetector is fabricated by coating a GaAs nanocone array with a monolayer graphene film, which shows high sensitivity to near‐infrared light irradiation, with good reproducibility, excellent selectivity, and rapid response speed.
      PubDate: 2014-01-21T12:41:06.00347-05:0
      DOI: 10.1002/adfm.201303368
       
  • A DNA Device that Mediates Selective Endosomal Escape and Intracellular
           Delivery of Drugs and Biologicals
    • Authors: Silvia Muro
      Pages: n/a - n/a
      Abstract: Design of materials to aid intracellular delivery of agents can greatly improve medical treatments. While DNA is a molecule difficult to introduce into cells, DNA can be engineered into devices capable of intracellular delivery. However, transport mediated by DNA devices void of other structural materials, with sizes greater than that associated with non‐specific penetration, and a targeting capacity enough to overcome non‐specific pathways has not yet been achived. This study demonstrates that this is possible. Submicrometer (200 nm) dendrimers built of DNA (nucleodendrimers (NDs)) are coupled to antibodies against selected cell‐surface receptors and compared to polymer nanoparticles (NPs). NDs and NPs bind specifically to cells expressing these targets and efficiently enter cells via the pathway associated with the selected receptor. While NPs traffic to perinuclear endo‐lysosomes, NDs remain scattered throughout the cell, suggesting endosomal escape. This is confirmed in vitro, where NDs disrupt membranous vesicles at endosomal‐like pH and in cell culture, where they provide endosomal escape of model drugs, sugars, proteins, and nucleic acids; allow access to other intracellular compartments; result in measurable effects of cargoes, and; do not cause cytotoxicity. Therefore, these DNA nanodevices can be used to selectively overcome intracellular barriers, underscoring the growing range of applications of DNA materials. DNA devices enter cells and provide cytosolic delivery. However, specificity of targeting and uptake via selected routes, as well as potential to deliver a broad spectrum of compounds intracellularly, has not been demonstrated. Using model 200 nm DNA dendrimers (nucleodendrimers), compared to control polymer nanoparticles, this work describes that both, high specificity and a wide range of applications can be achieved.
      PubDate: 2014-01-21T12:38:48.041406-05:
      DOI: 10.1002/adfm.201303188
       
  • Click Chemistry in Materials Science
    • Authors: Weixian Xi; Timothy F. Scott, Christopher J. Kloxin, Christopher N. Bowman
      Pages: n/a - n/a
      Abstract: Despite originating only a little more than a decade ago, click chemistry has become one of the most powerful paradigms in materials science, synthesis, and modification. By developing and implementing simple, robust chemistries that do not require difficult separations or harsh conditions, the ability to form, modify, and control the structure of materials on various length scales has become more broadly available to those in the materials science community. As such, click chemistry has seen broad implementation in polymer functionalization, surface modification, block copolymer and dendrimer synthesis, biomaterials fabrication, biofunctionalization, and in many other areas of materials science. Here, the basic reactions, approaches, and applications of click chemistry in materials science are highlighted, and a brief look is taken into the future enabling developments in this field. Click chemistry has become one of the most powerful paradigms in materials science, synthesis and modification. This feature article delivers highlights of the basic reactions, approaches, and applications of click chemistry in materials science as well as briefly looking to the future, enabling developments in this field.
      PubDate: 2014-01-21T12:35:28.218037-05:
      DOI: 10.1002/adfm.201302847
       
  • Triboelectric Nanogenerator as an Active UV Photodetector
    • Authors: Zong‐Hong Lin; Gang Cheng, Ya Yang, Yu Sheng Zhou, Sangmin Lee, Zhong Lin Wang
      Pages: n/a - n/a
      Abstract: Self‐powered nanosensors and nanosystems have attracted significant attention in the past decades and have gradually become the most desirable and promising prototype for environmental protection/detection because no battery is needed to power the device. Therefore, in this paper a design is proposed for a self‐powered photodetector based on triboelectric nanogenerator (TENG) configuration. 3D dendritic TiO2 nanostructures are synthesized as the built‐in UV photodetector as well as the contact material of the TENG. The cost‐effective, robust, and easily fabricated TENG‐based photodetector presents superior photoresponse characteristics, which include an excellent responsivity over 280 A W−1, rapid rise time (18 ms) and decay time (31 ms), and a wide detection range of light intensity from 20 μW cm−2 to 7 mW cm−2. In the last part of the paper, a stand‐alone and self‐powered environmental sensing device is developed by applying poly(methyl methacrylate) (PMMA) substrates and springs to assemble the TENG‐based photodetector. These results indicate that the new prototype sensing device based on the TENG configuration shows great potential as a self‐powered photodetector. A fully integrated and active UV photodetector based on a triboelectric nanogenerator configuration is successfully demonstrated. Dendritic TiO2 nanostructures are designed as a built‐in photodetector and contact material of the triboelectric nanogenerator. With the advantages of easy fabrication, low cost, rapid response time, and excellent responsivity, this self‐powered active UV photodetector presents a new approach for building functional devices.
      PubDate: 2014-01-21T12:33:32.492436-05:
      DOI: 10.1002/adfm.201302838
       
  • Dendron‐Based Micelles for Topical Delivery of Endoxifen: A
           Potential Chemo‐Preventive Medicine for Breast Cancer
    • Authors: Yang Yang; Ryan M. Pearson, Oukseub Lee, Chan‐Woo Lee, Robert T. Chatterton, Seema A. Khan, Seungpyo Hong
      Pages: n/a - n/a
      Abstract: Endoxifen (EDX) is an active metabolite of tamoxifen that has been proven effective in the prevention and treatment of estrogen‐positive breast cancer; however, oral administration of tamoxifen often causes severe side effects. Here, the topical delivery of EDX is explored using polymeric micelles to achieve localized drug delivery with potentially minimal side effects. EDX is encapsulated into dendron micelles (DM) with various surface groups (‐NH2, ‐COOH, or ‐Ac) and into cationic liposomes as a control. End‐group modification significantly affects the drug loading, where the DM‐COOH micelles allow the most efficient encapsulation. Furthermore, unlike the burst release from the liposomes, all DMs show sustained release of EDX over 6 days. Each formulation is evaluated for its potential to deliver EDX across the skin layers. DMs substantially enhance the permeation of EDX through both mouse (up to 20‐fold) and human (up to 4‐fold) skin samples relative to ethanol, a chemical penetration enhancer. Franz diffusion cell experiments reveal that DM‐COOH induces the highest flux of EDX among all groups. The enhanced drug loading, controlled release profiles, and enhanced skin permeation all demonstrate that DMs are a useful platform for the topical delivery of EDX, offering a potential alternative administration route for chemoprevention. Surface‐modified dendron micelles (DMs) are developed as a potential platform for the topical delivery of endoxifen (EDX). Skin permeation of EDX is highly dependent on the surface group of the DMs. In particular, carboxylated DMs exhibit significantly enhanced permeation of EDX through both mouse and human skin layers, offering a potential alternative administration route for chemoprevention.
      PubDate: 2014-01-20T10:39:59.024533-05:
      DOI: 10.1002/adfm.201303253
       
  • Highly Asymmetric, Interfaced Dimers Made of Au Nanoparticles and
           Bimetallic Nanoshells: Synthesis and Photo‐Enhanced Catalysis
    • Authors: Yongxing Hu; Yuzi Liu, Zheng Li, Yugang Sun
      Pages: n/a - n/a
      Abstract: Synthesis of a class of exotic interfaced dimers with high asymmetries in terms of composition, morphology, structure (solid versus hollow), and dimension of the individual nanoscale components in the dimers is successfully accomplished. Typical examples include the interfaced dimers made of solid Au nanoparticles and hollow bimetallic nanoshells with different compositions, such as Au/Ag, Pt/Ag, and Pd/Ag. The success of the synthesis relies on the combination of asymmetric overgrowth of Ag nanodomains on the partially passivated Au nanoparticles and a following galvanic replacement reaction between the Ag nanodomains and appropriate noble metal precursors. The entire synthesis is processed on the unique superparamagnetic colloidal substrates that offer many advantages, such as time‐efficiency, scalability, and high yield. The Au nanoparticle and the bimetallic nanoshell in each interfaced dimer are in direct contact, resulting in the possible strong coupling between them as well as novel properties that cannot be observed in either the nanoparticle or the nanoshell. For example, dimers made of Au nanoparticles and Pd/Ag nanoshells exhibit enhanced catalytic performance toward Suzuki coupling reactions under illumination of visible light because the strong surface plasmon resonances in the Au nanoparticles can influence the catalytic activity of the Pd/Ag nanoshells through coupling between the nanoparticles and the nanoshells. Highly asymmetric, interfaced dimers made of solid Au nanoparticles and hollow bimetallic nanoshells with different compositions are synthesized by combining the controlled growth of interfaced Au–Ag dimers and nanoscale galvanic replacement reactions on superparamagnetic colloidal substrates. The direct contact between the Au nanoparticle and the bimetallic nanoshells leads to possible strong couplings and novel properties.
      PubDate: 2014-01-20T03:23:03.270822-05:
      DOI: 10.1002/adfm.201303557
       
  • Solution‐Processable Hole‐Generation Layer and
           Electron‐Transporting Layer: Towards High‐Performance,
           Alternating‐Current‐Driven, Field‐Induced Polymer
           Electroluminescent Devices
    • Authors: Yonghua Chen; Yingdong Xia, Gregory M. Smith, Hengda Sun, Dezhi Yang, Dongge Ma, Yuan Li, Wenxiao Huang, David L. Carroll
      Pages: n/a - n/a
      Abstract: The effect of solution‐processed p‐type doping of hole‐generation layers (HGLs) and electron‐transporting layer (ETLs) are systematically investigated on the performance of solution‐processable alternating current (AC) field‐induced polymer EL (FIPEL) devices in terms of hole‐generation capability of HGLs and electron‐transporting characteristics of ETLs. A variety of p‐type doping conjugated polymers and a series of solution‐processed electron‐transporting small molecules are employed. It is found that the free hole density in p‐type doping HGLs and electron mobility of solution‐processed ETLs are directly related to the device performance, and that the hole‐transporting characteristics of ETLs also play an important role since holes need to be injected from electrode through ETLs to refill the depleted HGLs in the positive half of the AC cycle. As a result, the best FIPEL device exhibits exceptional performance: a low turn‐on voltage of 12 V, a maximum luminance of 20 500 cd m−2, a maximum current and power efficiency of 110.7 cd A−1 and 29.3 lm W−1. To the best of the authors' knowledge, this is the highest report to date among FIPEL devices driven by AC voltage. The effect of solution‐processed hole‐generation layers and electron‐transporting layers is systematically investigated on the performance of AC‐driven field‐induced polymer electroluminescence (FIPEL) devices. A low turn‐on voltage of 12 V, a maximum luminance of 20 500 cd m−2, and a maximum current and power efficiency of 110.7 cd A−1 and 29.3 lm W−1 are achieved. This study provides a pathway to high‐performance FIPEL device engineering.
      PubDate: 2014-01-16T23:26:00.685928-05:
      DOI: 10.1002/adfm.201303242
       
  • Alkoxy‐Functionalized Thienyl‐Vinylene Polymers for
           Field‐Effect Transistors and All‐Polymer Solar Cells
    • Authors: Hui Huang; Nanjia Zhou, Rocio Ponce Ortiz, Zhihua Chen, Stephen Loser, Shiming Zhang, Xugang Guo, Juan Casado, J. Teodomiro López Navarrete, Xinge Yu, Antonio Facchetti, Tobin J. Marks
      Pages: n/a - n/a
      Abstract: π‐conjugated polymers based on the electron‐neutral alkoxy‐functionalized thienyl‐vinylene (TVTOEt) building‐block co‐polymerized, with either BDT (benzodithiophene) or T2 (dithiophene) donor blocks, or NDI (naphthalenediimide) as an acceptor block, are synthesized and characterized. The effect of BDT and NDI substituents (alkyl vs alkoxy or linear vs branched) on the polymer performance in organic thin film transistors (OTFTs) and all‐polymer organic photovoltaic (OPV) cells is reported. Co‐monomer selection and backbone functionalization substantially modifies the polymer MO energies, thin film morphology, and charge transport properties, as indicated by electrochemistry, optical spectroscopy, X‐ray diffraction, AFM, DFT calculations, and TFT response. When polymer P7 is used as an OPV acceptor with PTB7 as a donor, the corresponding blend yields TFTs with ambipolar mobilities of μe = 5.1 × 10−3 cm2 V–1 s–1 and μh = 3.9 × 10−3 cm2 V–1 s–1 in ambient, among the highest mobilities reported to date for all‐polymer bulk heterojunction TFTs, and all‐polymer solar cells with a power conversion efficiency (PCE) of 1.70%, the highest reported PCE to date for an NDI‐polymer acceptor system. The stable transport characteristics in ambient and promising solar cell performance make NDI‐type materials promising acceptors for all‐polymer solar cell applications. Three classes of p‐ and n‐type conjugated polymers with different functional groups are designed and synthesized with electron neutral thienyl‐vinylene (TVTOEt) and electron rich or electron deficient building blocks. The different functional groups influence the polymer electronic energy levels, thin film morphologies, and charge transfer properties. The all‐polymer photovoltaic devices using the n‐type copolymer as the acceptor material exhibit good efficiency.
      PubDate: 2014-01-16T23:25:48.441132-05:
      DOI: 10.1002/adfm.201303219
       
  • Highly Fluorescent and Color‐Tunable Exciplex Emission from
           Poly(N‐vinylcarbazole) Film Containing Nanostructured Supramolecular
           Acceptors
    • Authors: Jong H. Kim; Byeong‐Kwan An, Seong‐Jun Yoon, Sang Kyu Park, Ji Eon Kwon, Chang‐Keun Lim, Soo Young Park
      Pages: n/a - n/a
      Abstract: Highly fluorescent excited‐state charge‐transfer complexes (exciplexes) formed at the interfacial region between a polymeric donor matrix, here, poly(N‐vinylcarbazole), and embedded nanostructured acceptors are characterized for their photophysical properties. Exciplex‐to‐exciton emission switching is observed after solvent vapor annealing (SVA) due to the size evolution of the nanostructures beyond the exciton diffusion length. Color‐tunable exiplex emission (sky blue, green, and orange) is demonstrated for three different nanostructured acceptors with the same HOMO–LUMO gap (i.e., the same blue excitonic emission) but with different electron affinity. White‐emitting poly(N‐vinylcarbazole) film is also fabricated, simply by incorporating mixed supramolecular acceptors, which provide independent exciplex emissions. This study presents important insights into the excited‐state intermolecular interaction at the well‐defined nanoscale interface and suggests an efficient way to obtain multicolored exciplex emissions. Color‐tunable exciplex emission based on a polymeric donor (PVK) and nanostructured acceptors is studied, including its ability to switch to exciton emission. Color‐tunable exciplexes are obtained by incorporating highly fluorescent acceptors with different molecular energy levels. Emission switching depending on the evolution of nanostructures at the donor–acceptor interface is investigated, taking advantage of self‐assembly of the supramolecular acceptors.
      PubDate: 2014-01-16T23:25:38.38307-05:0
      DOI: 10.1002/adfm.201302924
       
  • Nanostructured Hybrid Materials for the Selective Recovery and Enrichment
           of Rare Earth Elements
    • Authors: Justyna Florek; François Chalifour, François Bilodeau, Dominic Larivière, Freddy Kleitz
      Pages: n/a - n/a
      Abstract: The importance of rare‐earth elements (REEs) in the global economy is booming as they are used in numerous advanced technologies. Industrially, the extraction and purification of REEs involve multiple liquid–liquid extraction (LLE) steps as they exhibit very similar complexation properties with most common ligands. In order to substantially improve this process and provide a greener alternative to LLE, functional porous hybrid materials, demonstrating enhanced selectivity towards heavier REEs compared to commercially‐available products, are proposed. In addition, because of the grafting procedure used in the synthesis, the proposed materials demonstrate a higher degree of reusability, increasing their marketable potential. Nanomaterials for lanthanide separation: the importance of rare‐earth elements in the global economy is booming as they are used in numerous advanced technologies. However, industrially, their extraction and purification remain tedious. Functional porous hybrid materials demonstrate enhanced selectivity towards heavier rare‐earths compared to commercial products. Because of the grafting procedure used, these materials show high level of reusability, increasing their marketable potential.
      PubDate: 2014-01-16T07:11:12.247358-05:
      DOI: 10.1002/adfm.201303602
       
  • Energy Harvesting for Nanostructured Self‐Powered Photodetectors
    • Authors: Lin Peng; Linfeng Hu, Xiaosheng Fang
      Pages: n/a - n/a
      Abstract: Harvesting the available forms of energies in the environment to create self‐powered nanosystems is now becoming a technological reality. Self‐powered nanodevices and nanosystems are expected to play a crucial role in the future development of nanotechnology because of their specific role in fundamental studies and nanotechnological applications, mainly due to their size‐dependent properties and independent, sustainable, maintainance‐free operation. As a new field in self‐powered nanotechnology‐related research, self‐powered photodetectors have been developed which exhibit a much faster photoresponse and higher photosensitivity than the conventional photoconductor‐based photodetectors. Herein, the energy‐havesting techniques are discussed and their prospects for application in self‐powered photodetectors are summarized. Moreover, potential future directions of this research area are highlighted. As a new field in self‐powered nanotechnology‐related research, self‐powered photodetectors have been developed which exhibit a much faster photoresponse and higher photosensitivity than the conventional photoconductor‐based photodetectors. Energy‐harvesting techniques are discussed herein and their prospects for application in self‐powered photodetectors are summarized. Moreover, potential future directions of this research area are highlighted.
      PubDate: 2014-01-14T08:17:58.477211-05:
      DOI: 10.1002/adfm.201303367
       
  • Photothermal Killing of Cancer Cells by the Controlled Plasmonic Coupling
           of Silica‐Coated Au/Fe2O3 Nanoaggregates
    • Authors: Georgios A. Sotiriou; Fabian Starsich, Athanasia Dasargyri, Moritz C. Wurnig, Frank Krumeich, Andreas Boss, Jean‐Christophe Leroux, Sotiris E. Pratsinis
      Pages: n/a - n/a
      Abstract: Tumor ablation by thermal energy via the irradiation of plasmonic nanoparticles is a relatively new oncology treatment. Hybrid plasmonic‐superparamagnetic nanoaggregates (50–100 nm in diameter) consisting of SiO2‐coated Fe2O3 and Au (≈30 nm) nanoparticles were fabricated using scalable flame aerosol technology. By finely tuning the Au interparticle distance using the SiO2 film thickness (or content), the plasmonic coupling of Au nanoparticles can be finely controlled bringing their optical absorption to the near‐IR that is most important for human tissue transmittance. The SiO2 shell facilitates also dispersion and prevents the reshaping or coalescence of Au particles during laser irradiation, thereby allowing their use in multiple treatments. These nanoaggregates have magnetic resonance imaging (MRI) capability as shown by measuring their r2 relaxivity while their effectiveness as photothermal agents is demonstrated by killing human breast cancer cells with a short, four minute near‐IR laser irradiation (785 nm) at low flux (4.9 W cm‐2). Twin or Janus‐like gold‐iron‐oxide plas­monic‐superparamagnetic nano­aggregates are made by flame aerosol technology and wrapped up “in‐flight” by a transparent silica nanothin film. Its thickness finely tunes the near‐infrared absorption of Au nanoparticles allowing for a high light‐to‐heat efficiency, while iron‐oxide facilitates their magnetic placement and in‐vivo monitoring by MRI, and killing human breast cancer cells with a short, 4‐minute laser irradiation.
      PubDate: 2014-01-13T08:13:33.678723-05:
      DOI: 10.1002/adfm.201303416
       
  • Controlled Generation of Microspheres Incorporating Extracellular Matrix
           Fibrils for Three‐Dimensional Cell Culture
    • Authors: Victoria L. Workman; Liku B. Tezera, Paul T. Elkington, Suwan N. Jayasinghe
      Pages: n/a - n/a
      Abstract: A growing body of evidence suggests that studying cell biology in classical two‐dimensional formats, such as cell culture plasticware, results in misleading, non‐physiological findings. This paper describes the optimization of a microsphere‐based system permitting 3D cell culture incorporating physiological extracellular matrix components. Bio‐electrospraying, the most advanced method currently available, is used to produce microspheres containing THP‐1 cells as a model cell line. The bio‐electrospraying para­meters of nozzle size, polymer flow rate, and voltage are systematically investigated in order to allow stable production of size‐controlled microspheres containing extracellular matrix material and human cells. The effect of bio‐electrospraying parameters, alginate type and cell concentration on cell viability are investigated using trypan blue and propidium iodide staining. Bio‐electrospraying has no effect on cell viability nor the ability of cells to proliferate. Cell viability is similarly minimally affected by encapsulation in all types of alginate tested (MVM, MVG, chemical and food‐grade). Cell density of 5 × 106 cells mL−1 within microspheres is the optimum for cell survival and proliferation. The stable generation of microspheres incorporating cells and extracellular matrix for use in a 3D cell culture will benefit study of many diverse diseases and permit investigation of cellular biology within a 3D matrix. Three‐dimensional cell culture techniques are currently suboptimal. Parameters affecting bio‐electrospraying to generate cell‐containing microspheres incorporating extracellular matrix components are investigated. Cell viability is preserved and 3D bio‐electrospray cell culture systems have great potential to permit study of cells in a physiologically relevant environment pertinent to a wide range of cell biology.
      PubDate: 2014-01-13T02:09:32.403715-05:
      DOI: 10.1002/adfm.201303891
       
  • Core/Shell and Hollow Ultra High Molecular Weight Polyethylene Nanofibers
           and Nanoporous Polyethylene Prepared by Mesoscopic Shape Replication
           Catalysis
    • Authors: Georg F. J. Müller; Markus Stürzel, Rolf Mülhaupt
      Pages: n/a - n/a
      Abstract: Polyvinyl alcohol (PVA) nanofibers, produced by electrospinning, represent attractive high‐surface‐area supports for olefin polymerization catalysts. Tethered with metal alkyls, PVA nanofibers immobilize a great variety of transition metal compounds, thus producing highly active nanofiber‐supported Ziegler‐, metallocene‐, and post‐metallocene catalysts. Whereas most conventional heterogeneous polymerization catalysts form particles, PVA‐nanofiber‐supported catalysts enable polyolefin nanofiber and nanostructure formation by mesoscopic shape replication using electrospun nanofibers as templates. At low ethylene pressure, linear correlation between average PE/PVA core/shell fiber diameter and polymerization time are made. At elevated pressure, this control is lost, accounting for the formation of reactor blends consisting of PE granules and built‐in PE/PVA nanofibers. Whereas conventional catalysts produce micrometer‐sized particles of ultrahigh molecular weight PE (UHMWPE), PVA‐nanofiber supported chromium catalysts afford new families UHMWPE materials. They range from UHMWPE/PVA core/shell nanofibers and nonwovens to hollow UHMWPE fibers and nanoporous UHMWPE, obtained by removing the PVA component. Supporting single‐site catalysts on electrospun polyvinyl alcohol (PVA) nanofiber nonwovens enables the in‐situ formation of structured ultrahigh molecular weight polyethylene (UHMWPE) nanofibers during polymerization. Herein a new generation of shape‐replication catalysts producing nanoporous polyolefins, useful as solvent‐resistant filters, is investigated.
      PubDate: 2014-01-13T02:09:27.142469-05:
      DOI: 10.1002/adfm.201303465
       
  • Ion Gating: Light‐Gating Titania/Alumina Heterogeneous Nanochannels
           with Regulatable Ion Rectification Characteristic (Adv. Funct. Mater.
           4/2014)
    • Authors: Qianqian Zhang; Ziying Hu, Zhaoyue Liu, Jin Zhai, Lei Jiang
      Pages: 417 - 417
      Abstract: Artificial heterogeneous nanochannels with lightresponsive ion transport properties are demonstrated by Z. Liu, J. Zhai, and co‐workers on page 424. Their fabrication includes coating an anatase TiO2 porous layer onto an alumina porous supporter, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The decomposition of OTS molecules by TiO2 photocatalysis under UV light contributes to a change of surface wettability and an asymmetric distribution of surface negative charges, which realize the ion gating and regulatable ion rectification characteristics simultaneously.
      PubDate: 2014-01-23T08:17:07.283207-05:
      DOI: 10.1002/adfm.201470020
       
  • Drug Delivery: On‐Chip Fabrication of Paclitaxel‐Loaded
           Chitosan Nanoparticles for Cancer Therapeutics (Adv. Funct. Mater. 4/2014)
           
    • Authors: Fatemeh Sadat Majedi; Mohammad Mahdi Hasani‐Sadrabadi, Jules John VanDersarl, Nassir Mokarram, Shahirar Hojjati‐Emami, Erfan Dashtimoghadam, Shahin Bonakdar, Mohammad Ali Shokrgozar, Arnaud Bertsch, Philippe Renaud
      Pages: 418 - 418
      Abstract: The use of solvent‐free microfluidics to fine‐tune the physical and chemical properties of chitosan nanoparticles for drug delivery is demonstrated by J. J. VanDersarl, P. Renaud, and co‐workers on page 432. Controlling the time of mixing to within milliseconds during nanoparticle self‐assembly enables the adjustment of nanoparticle size, surface charge, and compactness, as well as drug‐loading efficiency. These drug‐loaded nanoparticles can be passively targeted to tumors, benefiting from enhanced permeability and retention, along with pH‐responsive release characteristics.
      PubDate: 2014-01-23T08:17:08.937664-05:
      DOI: 10.1002/adfm.201470021
       
  • Contents: (Adv. Funct. Mater. 4/2014)
    • Pages: 419 - 423
      PubDate: 2014-01-23T08:17:13.535131-05:
      DOI: 10.1002/adfm.201470023
       
  • Light‐Gating Titania/Alumina Heterogeneous Nanochannels with
           Regulatable Ion Rectification Characteristic
    • Authors: Qianqian Zhang; Ziying Hu, Zhaoyue Liu, Jin Zhai, Lei Jiang
      Pages: 424 - 431
      Abstract: Bioinspired artificial nanochannels exhibiting ion transport properties similar to biological ion channels have been attracting some attention for biosensors, separation technologies, and nanofluidic diodes. Herein, an easily available artificial heterogeneous nanochannel shows both ion gating and ion rectification characteristics when irradiated by ultraviolet light. The fabrication of heterogeneous nanochannels includes the coating of an anatase TiO2 porous layer on an alumina porous supporter, followed by a chemical modification with octadecyltrimethoxysilane (OTS) molecules. The irreversible decomposition of OTS molecules by TiO2 photocatalysis under ultraviolet light results in a change of surface wettability and an asymmetric distribution of surface negative charges simultaneously, which contributes to the ion gating and ion rectification. The asymmetric distribution of negative charges in the TiO2 porous layer can be controlled by the irradiation time of ultraviolet light, which regulates the ion rectification characteristic. Artificial nanochannels based on chemically modified TiO2/Al2O3 heterogeneous porous membranes are described. The irreversible decomposition of octadecyltrimethoxysilane (OTS) molecules by TiO2 photocatalysis under ultraviolet light results in a change of surface wettability and an asymmetric distribution of surface negative charges simultaneously, which contributes to the ion gating and regulatable ion rectification.
      PubDate: 2013-08-19T15:24:00.320266-05:
      DOI: 10.1002/adfm.201301426
       
  • On‐Chip Fabrication of Paclitaxel‐Loaded Chitosan
           Nanoparticles for Cancer Therapeutics
    • Authors: Fatemeh Sadat Majedi; Mohammad Mahdi Hasani‐Sadrabadi, Jules John VanDersarl, Nassir Mokarram, Shahirar Hojjati‐Emami, Erfan Dashtimoghadam, Shahin Bonakdar, Mohammad Ali Shokrgozar, Arnaud Bertsch, Philippe Renaud
      Pages: 432 - 441
      Abstract: The use of solvent‐free microfluidics to fine‐tune the physical and chemical properties of chitosan nanoparticles for drug delivery is demonstrated. Nanoparticle self‐assembly is driven by pH changes in a water environment, which increases biocompatibility by avoiding organic solvent contamination common with traditional techniques. Controlling the time of mixing (2.5–75 ms) during nanoparticle self‐assembly enables us to adjust nanoparticle size and surface potential in order to maximize cellular uptake, which in turn dramatically increases drug effectiveness. The compact nanostructure of these nanoparticles preserves drug potency better than previous nanoparticles, and is more stable during long‐term circulation at physiological pH. However, when the nanoparticles encounter a tumor cell and the associated drop in pH, the drug contents are released. Moreover, the loading efficiency of hydrophobic drugs into the nanoparticles increases significantly from previous work to over 95%. The microfluidic techniques used here have applications not just for drug‐carrying nanoparticle fabrication, but also for the better control of virtually any self‐assembly process. Using microfluidics to precisely regulate self‐assembly conditions, a number of nanoparticle properties are tuned to optimize drug‐delivery efficacy. These parameters include size, zeta potential, and pH responsiveness. These nanoparticles are stable during circulation at physiological pH, but if they encounter a tumor cell, where the pH is lower, they rapidly release their anti‐cancer drug cargo
      PubDate: 2013-08-05T00:40:53.593552-05:
      DOI: 10.1002/adfm.201301628
       
  • Biofunctional Micropatterning of Thermoformed 3D Substrates
    • Authors: Björn Waterkotte; Florence Bally, Pavel M. Nikolov, Ansgar Waldbaur, Bastian E. Rapp, Roman Truckenmüller, Jörg Lahann, Katja Schmitz, Stefan Giselbrecht
      Pages: 442 - 450
      Abstract: Mimicking the in vivo microenvironment of cells is a challenging task in engineering in vitro cell models. Surface functionalization is one of the key components providing biochemical cues to regulate the interaction between cells and their substrate. In this study, two different approaches yield biofunctional surface patterns on thermoformed polymer films. The first strategy based on maskless projection lithography enables the creation of grayscale patterns of biological ligands with a resolution of 7.5 μm in different shapes on a protein layer adsorbed on a polymer film. In the second strategy, polymer films are micropatterned with different functional groups via chemical vapor deposition polymerization. After thermoforming, both types of pattern can be decorated with proteins either by affinity binding or covalent coupling. The 3D microstructures retain the biofunctional patterns as demonstrated by selective cell adhesion and growth of L929 mouse fibroblasts. This combination of functional micropatterning and thermoforming offers new perspectives for the design of 3D cell culture platforms. Chemical vapor deposition polymerization and maskless projection lithography with protein adsorption by photobleaching (MPL‐PAP) in combination with microscale thermoforming are presented as two versatile technologies to create patterned biofunctionalized 3D substrates. These technologies provide new perspectives for bioanalytical applications and 3D cell culture platforms.
      PubDate: 2013-07-22T01:55:44.930563-05:
      DOI: 10.1002/adfm.201301093
       
  • NIR‐Triggered Synergic Photo‐chemothermal Therapy Delivered by
           Reduced Graphene Oxide/Carbon/Mesoporous Silica Nanocookies
    • Authors: Yu‐Wei Chen; Po‐Jung Chen, Shang‐Hsiu Hu, I‐Wei Chen, San‐Yuan Chen
      Pages: 451 - 459
      Abstract: A novel photo‐responsive drug carrier that doubles as a photothermal agent with a nanocookie‐like structure is constructed by coating amorphous carbon on a mesoporous silica support self‐assembled on a sheet of reduced graphene oxide. With a large payload (0.88 mmolg−1) of a hydrophobic anticancer drug, (S)‐(+)‐camptothecin (CPT), nanocookies simultaneously provide a burst‐like drug release and intense heat upon near‐infrared exposure. Being biocompatible yet with a high efficiency for cell uptake, nanocookies have successfully eradicated subcutaneous tumors in 14 days following a single 5 min NIR irradiation without distal damage. These results demonstrate that the nanocookie is an excellent new delivery platform for local, on‐demand, NIR‐responsive, combined chemotherapy/hyperthermia for tumor treatment and other biomedical applications. Formed by a one‐pot, scalable emulsion method and triggered by near infrared irradiation, photosensitive nanoparticles with a silica/carbon nanostructure supported on a reduced graphene oxide substrate can control release of hydrophobic chemotherapy drugs with synergistic hyperthermia effects, eradicating tumor cells in vivo and in vitro on demand.
      PubDate: 2013-08-23T02:10:50.303511-05:
      DOI: 10.1002/adfm.201301763
       
  • Amorphous Si3B3N7 Ceramic as a Versatile Host for Inorganic Phosphor
           Activators
    • Authors: Hasan Cakmak; Martin Jansen
      Pages: 460 - 464
      Abstract: Among the inorganic phosphors used in advanced lighting technologies, rare‐earth doped nitridosilicates have attracted significant attention because they exhibit superior photoluminescence properties in connection with high thermal, chemical, and mechanical stabilities. All of these materials are crystalline, which imposes substantial limitations in discovering new phosphors, since the activators to be included in the host matrix need to comply closely with the respective lattice sites, at least with respect to charge and size. As an approach to overcome such implications, an amorphous matrix, namely Si3B3N7, is suggested as a universal nitride‐based host accessible to (co)dope various activators, e.g., Eu2+, Ce3+ and Tb3+. Unlike crystalline phosphors, in the amorphous Si3B3N7 matrix, activator ions do not replace any atom from the random network host; instead, they act as network modifiers. The synthesis of this new class of amorphous phosphors is based on a precursor route, enabling high purities, and avoiding harsh temperature treatments. An amorphous Si3B3N7 network serves as a universal host for various activator ions to be used as inorganic phosphors, particularly for LED‐based lighting devices. This solution‐based synthesis route provides significant advantages, e.g., tuning the emission color of the phosphors via codoping with more than one activator ion in high purity and homogeneity.
      PubDate: 2013-09-03T11:31:47.04589-05:0
      DOI: 10.1002/adfm.201301743
       
  • A Pyrenylpropyl Phosphonic Acid Surface Modifier for Mitigating the
           Thermal Resistance of Carbon Nanotube Contacts
    • Authors: John H. Taphouse; O'Neil L. Smith, Seth R. Marder, Baratunde A. Cola
      Pages: 465 - 471
      Abstract: Efforts to utilize the high intrinsic thermal conductivity of carbon nanotubes (CNTs) for thermal transport applications, namely for thermal interface materials (TIMs), have been encumbered by the presence of high thermal contact resistances between the CNTs and connecting materials. Here, a pyrenylpropyl‐phosphonic acid surface modifier is synthesized and applied in a straight forward and repeatable approach to reduce the thermal contact resistance between CNTs and metal oxide surfaces. When used to bond nominally vertically aligned multi‐walled CNT forests to Cu oxide surfaces, the modifier facilitates a roughly 9‐fold reduction in the thermal contact resistance over dry contact, enabling CNT‐based TIMs with thermal resistances of 4.6 ± 0.5 mm2 K W−1, comparable to conventional metallic solders. Additional experimental characterization of the modifier suggests that it may be used to reduce the electrical resistance of CNT‐metal oxide contacts by similar orders of magnitude. A pyrenylpropyl phosphonic acid surface modifier is developed for coupling carbon nanotubes to metal oxide surfaces to reduce the thermal contact resistance. The modifier is demonstrated through experiment to reduce the thermal contact resistance between vertically aligned carbon nanotube forests and Cu oxide surfaces by roughly 9‐fold, enabling carbon nanotube‐based thermal interface materials with thermal resistances comparable to conventional metallic solders
      PubDate: 2013-09-04T01:45:39.394177-05:
      DOI: 10.1002/adfm.201301714
       
  • Cell‐Tethered Ligands Modulate Bone Remodeling by Osteoblasts and
           Osteoclasts
    • Authors: Rebecca S. Hayden; Jean‐Philippe Fortin, Benjamin Harwood, Balajikarthick Subramanian, Kyle P. Quinn, Irene Georgakoudi, Alan S. Kopin, David L. Kaplan
      Pages: 472 - 479
      Abstract: The goals of the present study are to establish an in vitro co‐culture model of osteoblast and osteoclast function and to quantify the resulting bone remodeling. The bone is tissue engineered using well‐defined silk protein biomaterials in 2D and 3D formats in combination with human cells. Parathyroid hormone (PTH) and glucose‐dependent insulinotropic peptide (GIP) are selected because of their roles in bone remodeling for expression in tethered format on human mesenchymal stem cells (hMSCs). The cell‐modified biomaterial surfaces are reconstructed from scanning electron microscopy images into 3D models for quantitative measurement of surface characteristics. Increased calcium deposition and surface roughness are found in 3D surface models of silk protein films remodeled by co‐cultures containing tethered PTH, and decreased surface roughness is found for the films remodeled by tethered GIP co‐cultures. Increased surface roughness is not found in monocultures of hMSCs expressing tethered PTH, suggesting that osteoclast‐osteoblast interactions in the presence of PTH signaling are responsible for the increased mineralization. These data point towards the design of in vitro bone models in which osteoblast‐osteoclast interactions are mimicked for a better understanding of bone remodeling. A method for modulating bone remodeling by osteoblasts and osteoclasts using cell‐tethered parathyroid hormone (tPTH) and glucose‐dependent insulinotropic peptide (tGIP) is described. Cell‐modified silk film biomaterial surfaces are reconstructed from scanning electron microscope images into three‐dimensional surface models using image processing for quantitative measurement of surface characteristics. tPTH increases remodeled surface roughness while tGIP has the opposite effect.
      PubDate: 2013-09-06T00:45:49.357983-05:
      DOI: 10.1002/adfm.201302210
       
  • Enzymatic Writing to Soft Films: Potential to Filter, Store, and Analyze
           Biologically Relevant Chemical Information
    • Authors: Yi Liu; Eunkyoung Kim, Morgan E. Lee, Boce Zhang, Yossef A. Elabd, Qin Wang, Ian M. White, William E. Bentley, Gregory F. Payne
      Pages: 480 - 491
      Abstract: Sensor‐based chemical analyses commonly enlist either the molecular recognition capabilities of biology (e.g., enzyme biosensors) or advanced information processing algorithms (e.g., the electronic nose). Here, a hybrid approach is proposed in which an enzyme is used to “filter” chemical information and write this information to a film which then serves as a permanent storage medium that can be ‘read’ repeatedly, interactively, and by multiple sensor modalities. This approach is demonstrated by analyzing common dietary phenols that are reported to offer health benefits. Specifically, the enzyme tyrosinase is used to convert these phenols into reactive quinones that graft (i.e., write) to a chitosan film. Grafting can be detected by optical, mechanical, and electrochemical sensors. Importantly, grafting confers redox activity to the films and this redox activity can be probed interactively by advanced electrochemical methods that allow the intrinsic redox reactivities to be compared, redox interactions to be identified, and biologically relevant redox activities to be examined. The transfer of chemical and biological information to a film is envisioned to provide broader access to the extensive capabilities offered by sensor technologies and signal processing methodologies. An enzyme is used to “filter” chemical information and write this information to a hydrogel film, which then serves as a permanent storage medium that can be ‘read’ repeatedly, interactively, and by multiple sensor modalities. Potentially, this approach will be applicable for problems such as analysis of the health benefits of dietary phenols.
      PubDate: 2013-08-16T05:06:52.541775-05:
      DOI: 10.1002/adfm.201301434
       
  • Spray‐Layer‐by‐Layer Carbon Nanotube/Electrospun Fiber
           Electrodes for Flexible Chemiresistive Sensor Applications
    • Authors: Kittipong Saetia; Jan M. Schnorr, Matthew M. Mannarino, Sung Yeol Kim, Gregory C. Rutledge, Timothy M. Swager, Paula T. Hammond
      Pages: 492 - 502
      Abstract: Development of a versatile method for incorporating conductive materials into textiles could enable advances in wearable electronics and smart textiles. One area of critical importance is the detection of chemicals in the environment for security and industrial process monitoring. Here, the fabrication of a flexible, sensor material based on functionalized multi‐walled carbon nanotube (MWNT) films on a porous electrospun fiber mat for real‐time detection of a nerve agent simulant is reported. The material is constructed by layer‐by‐layer (LbL) assembly of MWNTs with opposite charges, creating multilayer films of MWNTs without binder. The vacuum‐assisted spray‐LbL process enables conformal coatings of nanostructured MWNT films on individual electrospun fibers throughout the bulk of the mat with controlled loading and electrical conductivity. A thiourea‐based receptor is covalently attached to the primary amine groups on the MWNT films to enhance the sensing response to dimethyl methylphosphonate (DMMP), a simulant for sarin nerve agent. Chemiresistive sensors based on the engineered textiles display reversible responses and detection limits for DMMP as low as 10 ppb in the aqueous phase and 5 ppm in the vapor phase. This fabrication technique provides a versatile and easily scalable strategy for incorporating conformal MWNT films into three‐dimensional substrates for numerous applications. Flexible sensory material based on conformal multi‐walled carbon nanotube (MWNT) films on a porous electrospun polymeric fiber mat is constructed using a vacuum‐assisted spray layer‐by‐layer assembly. The resulting thin MWNT films coat individual electrospun fibers with controlled loading and electrical conductivity. The MWNT/electrospun fiber electrodes display reversible responses and high sensitivity for detecting DMMP in aqueous and vapor phases.
      PubDate: 2013-09-20T02:21:09.768897-05:
      DOI: 10.1002/adfm.201302344
       
  • Photostable Iodinated Silica/Porphyrin Hybrid Nanoparticles with
           Heavy‐Atom Effect for Wide‐Field Photodynamic/Photothermal
           Therapy Using Single Light Source
    • Authors: Koichiro Hayashi; Michihiro Nakamura, Hirokazu Miki, Shuji Ozaki, Masahiro Abe, Toshio Matsumoto, Toshinari Kori, Kazunori Ishimura
      Pages: 503 - 513
      Abstract: Physical therapies including photodynamic therapy (PDT) and photothermal therapy (PTT) can be effective against diseases that are resistant to chemotherapy and remain as incurable malignancies (for example, multiple myeloma). In this study, to enhance the treatment efficacy for multiple myeloma using the synergetic effect brought about by combining PDT and PTT, iodinated silica/porphyrin hybrid nanoparticles (ISP HNPs) with high photostability are developed. They can generate both 1O2 and heat with irradiation from a light‐emitting diode (LED), acting as photosensitizers for PDT/PTT combination treatment. ISP HNPs exhibit the external heavy atom effect, which significantly improves both the quantum yield for 1O2 generation and the light‐to‐heat conversion efficiency. The in vivo fluorescence imaging demonstrates that ISP HNPs, modified with folic acid and polyethylene glycol (FA‐PEG‐ISP HNPs), locally accumulate in the tumor after 18 h of their intravenous injection into tumor‐bearing mice. The LED irradiation on the tumor area of the mice injected with FA‐PEG‐ISP HNPs causes necrosis of the tumor tissues, resulting in the inhibition of tumor growth and an improvement in the survival rate. Photodynamic/photothermal combination therapy using iodinated silica/porphyrin hybrid nanoparticles (ISP HNPs) inhibits tumor growth. The ISP HNPs have high photostability, and they efficiently generate both 1O2 and heat with irradiation from an LED because of the external heavy‐atom effect. The surface‐modified ISP HNPs accumulate in tumor tissue. Light irradiation to the tumor leads to the death of tumor cells.
      PubDate: 2013-08-19T15:24:18.725333-05:
      DOI: 10.1002/adfm.201301771
       
  • Transparent, Flexible Films Based on Layered Double Hydroxide/Cellulose
           Acetate with Excellent Oxygen Barrier Property
    • Authors: Yibo Dou; Simin Xu, Xiaoxi Liu, Jingbin Han, Hong Yan, Min Wei, David G. Evans, Xue Duan
      Pages: 514 - 521
      Abstract: Transparent and flexible multilayer films are fabricated based on the alternating assembly of cellulose acetate (CA) and layered double hydroxide (LDH) nanoplatelets followed by thermal annealing treatment. The films exhibit tremendously enhanced oxygen barrier properties. The oxygen transmission rate (OTR) of the resulting (CA/LDH)n multilayer films can be tuned by changing the aspect ratio of high‐crystalline LDH nanoplatelets from 20 to 560. The (CA/LDH)20 film displays excellent oxygen‐barrier behavior with an OTR equal to or below the detection limit of commercial instrumentation (
      PubDate: 2013-08-21T14:15:46.749708-05:
      DOI: 10.1002/adfm.201301775
       
  • A Multi‐synergistic Platform for Sequential
           Irradiation‐Activated High‐Performance Apoptotic Cancer
           Therapy
    • Authors: Zhaowei Chen; Zhenhua Li, Jiasi Wang, Enguo Ju, Li Zhou, Jinsong Ren, Xiaogang Qu
      Pages: 522 - 529
      Abstract: Artificial hyperthermia is an emerging technique to induce apoptotic cancer cell death. However, achieving effective hyperthermic apoptosis is often difficult, as cells typically acquire resistance to thermal stress. With the aid of sequential irradiation, highly integrated nanoassemblies based on reduced graphene oxide–ZnO nanoparticles–hyaluronic acid (rGo‐ZnO‐HA) can serve as a multi‐synergistic platform for targeted high‐performance apoptotic cancer therapy. The surface engineering of ZnO/graphene hybrid with multifunctional HA biomacromolecules simultaneously confers the system colloidal stability, biocompatibility, and a cancer cell targeting ability. After receptor‐mediated endocytosis, enzyme‐mediated fluorescence activation helps track cellular uptake and provides truly molecular imaging. Furthermore, the reactive oxygen species (ROS) generated by ZnO/rGo under light illumination can effectively sensitize cancer cells to the subsequent NIR laser‐induced apoptotic hyperthermia. In particular, photo modulation of cellular ROS to sensitize cells provides a novel approach to increase the efficacy of hyperthermic apoptosis. These findings suggest that a powerful apoptotic therapeutic platform could be achieved based on the multi‐synergistic platform. With the aid of sequential irradiation, highly integrated reduced graphene oxide–ZnO nanoparticle–hyaluronic acid nanoassemblies can serve as a multi‐synergistic platform for targeted high‐performance apoptotic cancer therapy. The reactive oxygen species generated by ZnO/rGo under light irradiation can effectively sensitize cancer cells to the subsequent NIR laser‐induced apoptotic hyperthermia.
      PubDate: 2013-10-22T00:55:32.453607-05:
      DOI: 10.1002/adfm.201301951
       
  • Self‐Assembly of Multiple Stacked Nanorings by Vertically Correlated
           Droplet Epitaxy
    • Authors: Jiang Wu; Yusuke Hirono, Xinlei Li, Zhiming M. Wang, Jihoon Lee, Mourad Benamara, Siyuan Luo, Yuriy I. Mazur, Eun Soo Kim, Gregory J. Salamo
      Pages: 530 - 535
      Abstract: Fabrication of advanced artificial nanomaterials is a long‐term pursuit to fulfill the promises of nanomaterials. In the last ten years, Droplet Epitaxy has been emerging as a versatile fabrication method for various complex nanomaterials, but there is a lack of growth protocol to control the growth vertically. Here we report a vertically correlated Droplet Epitaxy growth method. We find that the nanodroplets form preferable on the preexisting nanorings, which enables fabrication of vertically aligned nanostructures by Droplet Epitaxy. Nucleation thermodynamics and growth kinetics have been proposed to explain the vertically correlated Droplet Epitaxy. Heterojunctions can be realized at nanoscale by the presented method. In addition, the nucleation thermodynamics of nanodroplets observed in this article will allow site‐controlled fabrication of nanostructures. The nanodroplets preferably form on pre‐existing nanorings, which enables fabrication of vertically aligned nanostructures by droplet epitaxy. Nucleation thermodynamics and growth kinetics are proposed to explain the vertically correlated droplet epitaxy. Heterojunctions can be realized at the nanoscale by this method. In addition, the nucleation thermodynamics of these nanodroplets will allow site‐controlled fabrication of nanostructures.
      PubDate: 2013-08-12T02:50:51.093871-05:
      DOI: 10.1002/adfm.201302032
       
  • Phototunable Underwater Oil Adhesion of Micro/Nanoscale
           
    • Authors: Dongliang Tian; Zhenyan Guo, Yiliang Wang, Wenxian Li, Xiaofang Zhang, Jin Zhai, Lei Jiang
      Pages: 536 - 542
      Abstract: Controllable surface adhesion of solid substrates has aroused great interest both in air and underwater in solving many challenging interfacial science problems such as robust antifouling, oil‐repellent, and highly efficient oil/water separation materials. Recently, responsive surface adhesion, especially switchable adhesion, under external stimulus in air has been paid more and more attention in fundamental research and industrial applications. However, phototunable underwater oil adhesion is still a challenge. Here, an approach to realize phototunable underwater oil adhesion on aligned ZnO nanorod array‐coated films is reported, via a special switchable contact mode between an unstable liquid/gas/solid tri‐phase contact mode and stable liquid/liquid/solid tri‐phase contact mode. The photo‐induced wettability transition to water and air exists (or does not) in the micro/nanoscale hierarchical structure of the mesh films, playing important role in controlling the underwater oil adhesion behavior. This work is promising in the design of novel interfacial materials and functional devices for practical applications such as photo‐induced underwater oil manipulation and release, with loss‐free oil droplet transportation. Phototunable oil adhesion underwater on micro/nanoscale hierarchical structured ZnO mesh films with switchable contact mode between UV irradiation and storage in the dark is demonstrated. This work is promising for photocontrollable underwater oil adhesion, and may also provide interesting insight into the design of novel materials and functional devices based on the controllable adhesion of oil at surfaces.
      PubDate: 2013-10-27T04:05:40.375476-05:
      DOI: 10.1002/adfm.201301799
       
  • π‐Conjugated Molecules Crosslinked Graphene‐Based
           
    • Authors: Xiaowei Ou; Penglei Chen, Lang Jiang, Yunfan Shen, Wenping Hu, Minghua Liu
      Pages: 543 - 554
      Abstract: Graphene‐based ultrathin films with tunable performances, controlled thickness, and high stability are crucial for their uses. The currently existing protocols, however, could hardly simultaneously meet these requirements. Using amino‐substituted π‐conjugated compounds, including 1,4‐diaminobenzene (DABNH2), benzidine (BZDNH2), and 5,10,15,20‐tetrakis (4‐aminophenyl)‐21H,23H‐porphine (TPPNH2), as cross‐linkages, a new protocol through which graphene oxide (GO) nanosheets can be anchored on solid supports with a high stability and controlled thickness via a layer‐by‐layer method is presented. A thermal annealing leads to the reduction of the films, and the qualities of the samples can be inherited by the as‐produced reduced GO films (RGO). When RGO films are integrated as source/drain electrodes in OFETs, tunable performances can be realized. The devices based on the BZDNH2‐crosslinked RGO electrodes exhibit similar electrical behaviors as those based on the non‐π‐conjugated compound crosslinked electrodes, while improved performances can be gained when those crosslinked by DABNH2 are used. The performances can be further improved when RGO films crosslinked by TPPNH2 are employed. This work likely paves a new avenue for graphene‐based films of tunable performances, controlled thickness, and high stability. Graphene‐based ultrathin films simultaneously featured with tunable performance, controlled thickness, and high stability, are integrated using π‐conjugated molecules as cross‐linkages. The use of dual functional linkage endows our new protocol with broad opportunities for desired motives in terms of using elaborately‐designed linkages of desired functions.
      PubDate: 2013-09-03T02:25:20.790053-05:
      DOI: 10.1002/adfm.201302153
       
  • Highly Efficient Yellow Organic Light Emitting Diode with a Novel
           Wet‐ and Dry‐Process Feasible Iridium Complex Emitter
    • Authors: Jwo‐Huei Jou; You‐Xing Lin, Shiang‐Hau Peng, Chieh‐Ju Li, Yu‐Min Yang, Chih‐Lung Chin, Jing‐Jong Shyue, Shih‐Sheng Sun, Mandy Lee, Chien‐Tien Chen, Ming‐Chung Liu, Cheng‐Chang Chen, Guan‐Yu Chen, Jin‐Han Wu, Cheng‐Hung Li, Chao‐Feng Sung, Mei‐Ju Lee, Je‐Ping Hu
      Pages: 555 - 562
      Abstract: Yellow emission is crucial in RGBY display technology and in fabricating physiologically friendly, low color‐temperature lighting sources. Emitters with both wet‐ and dry‐process feasibility are highly desirable to fabricate, respectively, high‐quality devices via vapor deposition and cost‐effective, large‐area devices via roll‐to‐roll fabrication. Here, high‐efficiency organic light‐emitting diodes with a novel wet‐ and dry‐process feasible yellow‐emitting iridium complex, bis[5‐methyl‐7‐fluoro‐5H‐benzo(c)(1,5) naphthyridin‐6‐one]iridium (picolinate), are demonstrated. By spin coating, the device shows, at 1000 cd m−2, an external quantum efficiency (EQE) of 18.5% with an efficacy of 52.3 lm W−1, the highest among all reported yellow devices via wet‐process, while using vapor deposition, the EQE is 22.6% with a 75.1 lm W−1 efficacy, the highest among all dry‐processed counterparts. The high efficiency may be attributed to the replacement of the hydrogen atom with a fluorine atom on a 2‐substitutional site in the emitter to prevent dense molecular packing‐caused self‐quenching and to reduce radiationless deactivation rates, leading to a high quantum yield (71%). A highly efficient, iridium‐based, yellow emitter with both dry‐ and wet‐process feasibility is presented. The yellow OLED device exhibits, at 1000 cd m−2, an efficacy of 75 lm W−1 via evaporation deposition, the highest among all reported dry‐processed yellow OLEDs, and 52 lm W−1 via spin‐coating, the highest among all wet‐processed counterparts.
      PubDate: 2013-08-05T00:41:11.430141-05:
      DOI: 10.1002/adfm.201302013
       
 
 
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