6 research outputs found

    Two-Dimensional Micropatterns via Crystal Growth of Na<sub>2</sub>CO<sub>3</sub> for Fabrication of Transparent Electrodes

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    The simple and versatile method to generate two-dimensional micropatterns by controlling precisely crystallization of sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>) was investigated. Dense clusters of dendrites of salt crystals were homogeneously formed in a large area with an aqueous solution of Na<sub>2</sub>CO<sub>3</sub> during evaporation of water. The dimensions and morphologies of dendritic salt crystals were tuned by changing the growth conditions such as salt concentration, relative humidity, and temperature. Then, 2D micropatterns of salt crystals were directly used as a mask for the deposition of a silver (Ag) layer to fabricate transparent electrodes. After salt crystals were completely dissolved in water, the network of an electrically conductive Ag layer, whose patterns were reversely produced from salt crystals, was generated on glass substrates. In addition, salt crystals were used as a master to prepare a replica mold of poly­(dimethylsiloxane) (PDMS) for utilizing the imprinting technique. By imprinting a flexible PDMS mold with Ag inks, Ag micropatterns that were perfectly identical to dendrites of salt crystals were transferred to the other substrate

    Conducting polymer based visible light photocatalytic composites for pollutant removal: Progress and prospects

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    Conducting polymers (CPs) have been proved to be instrumental in enhancing photocatalytic efficacy owing to their unique physicochemical properties and energy levels. In this regard, titanium dioxide (TiO2) has been investigated in transdisciplinary research areas (like catalysis, energy technologies, health, and environment) due to its desirable characteristics. In the process of developing advanced photocatalysts, novel inorganic–organic heterojunction design based materials have been explored and developed in contrast to conventional, inorganic–inorganic type semiconducting photocatalysts (SCPs). In this context, hybrid/composite SCPs comprising CPs and TiO2, have received significant attention for enhancing photocatalytic efficacy in terms of activity as well as visible light activation. The synergistic contribution from CPs (here we focus only on polyaniline (PANI) and polypyrrole (PPy)) and TiO2 have been proved to enhance light-absorption capability in the visible region, photogenerated extraction, and higher stability. Importantly, the published literature (before 2015) on the photocatalysis of TiO2-CP composites mainly discusses in terms of the sensitizing aspects of CP for TiO2. However, there is a critical need to review the literature (beyond 2015) to explore the state of art progress concerning the mechanism of photocatalytic performances as phenomenal parallel developments and knowledge gaps have been addressed on new kinds of heterojunction formation (like S-Scheme over traditional ones), band tuning and interfacial contact effects between two SCPs. In particular, this topical review aims to capture and highlight the current advancements (2016–2021) in relevance to the visible light photocatalytic performance of CP–TiO2 functional composites, which include nanostructures and multi-components. The predominantly available literature over the last five years on the application of CPs–TiO2 functional composites for monitoring or removal of pollutants under visible light activation is reviewed giving importance to revealing the role of CP in concurrent enhancement in both visible light activation and photocatalytic performances. Finally, we elaborate on the challenges and future outlook for advanced research and development in this area

    Tumor-Homing Glycol Chitosan-Based Optical/PET Dual Imaging Nanoprobe for Cancer Diagnosis

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    Imaging techniques including computed tomography, magnetic resonance imaging, and positron emission tomography (PET) offer many potential benefits to diagnosis and treatment of cancers. Each method has its own strong and weak points. Therefore, multimodal imaging techniques have been highlighted as an alternative method for overcoming the limitations of each respective imaging method. In this study, we fabricated PET/optical activatable imaging probe based on glycol chitosan nanoparticles (CNPs) for multimodal imaging. To prepare the dual PET/optical probes based on CNPs, both <sup>64</sup>Cu radiolabeled DOTA complex and activatable matrix metalloproteinase (MMP)-sensitive peptide were chemically conjugated onto azide-functionalized CNPs via bio-orthogonal click chemistry, which was a reaction between azide group and dibenzyl cyclooctyne. The PET/optical activatable imaging probes were visualized by PET and optical imaging system. Biodistribution of probes and activity of MMP were successfully measured in tumor-bearing mice

    Facile use of silver nanoparticles-loaded alumina/silica in nanofluid formulations for enhanced catalytic performance toward 4-nitrophenol reduction

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    The introduction of toxic chemicals into the environment can result in water pollution leading to the degradation of biodiversity as well as human health. This study presents a new approach of using metal oxides (Al₂O₃ and SiO₂) modified with a plasmonic metal (silver, Ag) nanoparticles (NPs)-based nanofluid (NF) formulation for environmental remediation purposes. Firstly, we prepared the Al₂O₃ and SiO₂ NFs of different concentrations (0.2 to 2.0 weight %) by ultrasonic-assisted dispersion of Al₂O₃ and SiO₂ NPs with water as the base fluid. The thermo-physical (viscosity, activation energy, and thermal conductivity), electrical (AC conductivity and dielectric constant) and physical (ultrasonic velocity, density, refractive index) and stability characteristics were comparatively evaluated. The Al₂O₃ and SiO₂ NPs were then catalytically activated by loading silver NPs to obtain Al₂O₃/SiO₂@Ag composite NPs. The catalytic reduction of 4-nitrophenol (4-NP) with Al₂O₃/SiO₂@Ag based NFs was followed. The catalytic efficiency of Al₂O₃@Ag NF and SiO₂@Ag NF, for the 4-NP catalysis, is compared. Based on the catalytic rate constant evaluation, the catalytic reduction efficiency for 4-NP is found to be superior for 2% weight Al₂O₃@Ag NF (92.9 × 10⁻³ s⁻¹) as compared to the SiO₂@Ag NF (29.3 × 10⁻³ s⁻¹). Importantly, the enhanced catalytic efficiency of 2% weight Al₂O₃@Ag NF for 4-NP removal is much higher than other metal NPs based catalysts reported in the literature, signifying the importance of NF formulation-based catalysis

    Facile Method To Radiolabel Glycol Chitosan Nanoparticles with <sup>64</sup>Cu via Copper-Free Click Chemistry for MicroPET Imaging

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    An efficient and straightforward method for radiolabeling nanoparticles is urgently needed to understand the <i>in vivo</i> biodistribution of nanoparticles. Herein, we investigated a facile and highly efficient strategy to prepare radiolabeled glycol chitosan nanoparticles with <sup>64</sup>Cu via a strain-promoted azide–alkyne cycloaddition strategy, which is often referred to as click chemistry. First, the azide (N<sub>3</sub>) group, which allows for the preparation of radiolabeled nanoparticles by copper-free click chemistry, was incorporated to glycol chitosan nanoparticles (CNPs). Second, the strained cyclooctyne derivative, dibenzyl cyclooctyne (DBCO) conjugated with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator, was synthesized for preparing the preradiolabeled alkyne complex with <sup>64</sup>Cu radionuclide. Following incubation with the <sup>64</sup>Cu-radiolabeled DBCO complex (DBCO-PEG<sub>4</sub>-Lys-DOTA-<sup>64</sup>Cu with high specific activity, 18.5 GBq/μmol), the azide-functionalized CNPs were radiolabeled successfully with <sup>64</sup>Cu, with a high radiolabeling efficiency and a high radiolabeling yield (>98%). Importantly, the radiolabeling of CNPs by copper-free click chemistry was accomplished within 30 min, with great efficiency in aqueous conditions. In addition, we found that the <sup>64</sup>Cu-radiolabeled CNPs (<sup>64</sup>Cu-CNPs) did not show any significant effect on the physicochemical properties, such as size, zeta potential, or spherical morphology. After <sup>64</sup>Cu-CNPs were intravenously administered to tumor-bearing mice, the real-time, <i>in vivo</i> biodistribution and tumor-targeting ability of <sup>64</sup>Cu-CNPs were quantitatively evaluated by microPET images of tumor-bearing mice. These results demonstrate the benefit of copper-free click chemistry as a facile, preradiolabeling approach to conveniently radiolabel nanoparticles for evaluating the real-time <i>in vivo</i> biodistribution of nanoparticles
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