Solution based rapid synthesis of AgCuO₂ at room temperature

We report a single step synthesis of AgCuO2 within minutes resulting in a polycrystalline, single phase product crystallizing in a monoclinic system. Chemical composition analysis has confirmed the stoichiometry of the product with oxygen in slight excess (∼0.1). Growth of this oxide involved cuboidal nanoparticles in the initial stages and needle-like microstructures in the final one, as shown by scanning electron microscopy. The novelty of the method lies in the stabilization of Cu in the 3+ state under ambient conditions in a rapid aqueous process

Modulated in Vitro Biocompatibility of a Unique Cross-Linked Salicylic Acid-Poly(epsilon-caprolactone)-Based Biodegradable Polymer

Herein, we report the development of a unique architecture by chemically cross-linking salicylic acid (SA)-based poly(anhydride ester) onto a biodegradable amine-functionalized poly(caprolactone) (PCL), using lactic acid as a spacer. The ester and amide linkages in the SA PCL polymer, synthesized through melt condensation, were confirmed by NMR and FT-IR spectroscopic techniques. The enzymatic and nonenzymatic hydrolytic degradation profile exhibited linear degradation kinetics over an extended time period (>5 weeks). The compatibility and growth of C2C12 myoblast cells were found to be significantly improved on the fast-degrading SA PCL substrates compared to those over neat PCL and amine-functionalized PCL. Further, the decreased red blood cell damage, illustrated by 0.39% hemolysis activity and a minimal number of platelet adhesion on a SA PCL polymeric surface confirmed good hemocompatibility of the as-synthesized polymer. Together with a moderate bactericidal property, the spectrum of properties of this novel polymer can be attributed to the synergistic effect of the presence of chemical moieties of SA and amine groups in PCL. In summary, it is considered that a SA PCL-based cross-linked composite can be utilized as a new biodegradable polymer

Synthesis of a Block Copolymer Exhibiting Cell-Responsive Phytochemical Release for Cancer Therapy

Phytochemicals constitute a promising class of therapeutics for the treatment of various diseases, but, their delivery poses significant challenges. In this work, a nanoscale polyactive emulsion was designed for smart, cell-responsive delivery of a curcumin prodrug (curcumin dicarboxylate, CDA) that was chemically conjugated to enzymatically labile oligo-peptides with polycaprolactone (PCL) as the carrier. Matrix metalloproteinase (MMP)-sensitive (PLGLYAL) or nonsensitive (GPYYPLG) peptides were used as spacers for conjugating CDA and PCL. This CDA nanoemulsion incorporating the MMP-sensitive sequence exhibited markedly higher anti-cancer activity, cell internalization, and generation of reactive oxygen species in cancer cells in vitro than the control with the nonsensitive oligopeptide. Moreover, the nanopolyactives induced minimal cytotoxicity in noncancerous cell line. This work presents a unique strategy to engineer smart nano-polyactives for efficient and targeted delivery of phytochemicals

Facile one-pot scalable strategy to engineer biocidal silver nanocluster assembly on thiolated PVDF membranes for water purification

Biofouling, due to bacterial growth and colonization, is a significant obstacle in water treatment that severely affects the membrane performance. Nanofiltration effectively removes viruses and other pathogens but is an energy intensive process. Designing and developing low pressure driven membranes with potential antimicrobial and antibiofouling properties is a concern. Under this framework, biocidal silver nanoparticles based polymeric membranes with high content of silver on the membrane surface can control bacterial colonization. However, leaching of silver during water treatment may also lead to toxicity. In the present work, a unique strategy resulting in distinct surface assembly of silver nanoparticles was established on thiol functionalized PVDF membranes. Nanocluster assembly of silver nanoparticles on the PVDF membrane was obtained by esterification reaction between thioglycolic acid (TGA) and alkaline treated PVDF membrane (TGA-PVDF). On the other hand, by introducing thiol-ene chemistry between pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) and alkaline treated PVDF (PETMP-PVDF), well dispersed silver nanoparticles can be tailored on the membrane surface. The silver nanocluster assembly on TGA-PVDF membranes results in control leaching, as confirmed by inductively coupled plasma atomic emission spectroscopy (ICP) and X-ray photon spectroscopy (XPS) analysis in striking contrast to PETMP-PVDF. The trans-membrane flux was assessed and our results uncover that the designed membranes showed higher flux rate. These results have important implications in designing membranes for water purification and reveal the importance of the surface assembly of biocidal nanoparticles towards antibacterial properties

Selective cleavage of the polyphosphoester in crosslinked copper based nanogels: enhanced antibacterial performance through controlled release of copper

Polymeric architectures with controlled and well-defined structural features are required to render a sustainable antibacterial surface - a key requirement in the design of polymeric membranes for water purification. Herein, surface selective crosslinking of copper oxide-polyphosphoester (CuO-PPE) hybrid nanogels on to polyvinylidene fluoride-styrene maleic anhydride (PVDF/SMA) ultrafiltration membranes was developed. The hybrid nanogels, composed of PPE and CuO, with inherent antifouling and antibacterial properties, were crosslinked using a macroinitiator (polyethylene glycol, PEG) and subsequently grafted on to PVDF/SMA by alkyne-anhydride reaction. Partially hydrolysed SMA solubilizes membrane proteins and the phosphatase/phospholipase triggers the cleavage of PPE segments resulting in controlled release of Cu ions. This unique strategy renders the membrane surface antibacterial through sustained and controlled release of Cu ions thereby generating intracellular reactive oxygen species (ROS). In addition, the enhanced antibiofouling performance of these membranes is facilitated by the presence of the hydrophilic macroinitiator (PEG and PPE). The modified membranes designed in this study are durable and possess long-term stability due to strong covalent interaction between CuO-PPE and the PVDF/SMA membrane. Studies on the flux, porosity and protein adsorption of the membranes were performed. An enhanced flux recovery ratio was observed for the modified membrane due to the pendant PPE groups (from CuO-PPE) which prohibit irreversible protein adsorption on the PVDF surface. The cytotoxicity of CuO-PPE is greatly reduced because of an effective coverage of CuO by biocompatible PPEs. This study opens up new avenues of fabricating ``smart'' inorganic nanoparticles that can be confined in a soft hybrid polymeric gel network with controlled release of Cu ions thereby precluding ubiquitous bacterial treatment in water filtration systems

Large-scale hydrologic modeling in the Baltic basin

NR 20140805</p

Selective cleavage of the polyphosphoester in crosslinked copper based nanogels: enhanced antibacterial performance through controlled release of copper

Polymeric architectures with controlled and well-defined structural features are required to render a sustainable antibacterial surface - a key requirement in the design of polymeric membranes for water purification. Herein, surface selective crosslinking of copper oxide-polyphosphoester (CuO-PPE) hybrid nanogels on to polyvinylidene fluoride-styrene maleic anhydride (PVDF/SMA) ultrafiltration membranes was developed. The hybrid nanogels, composed of PPE and CuO, with inherent antifouling and antibacterial properties, were crosslinked using a macroinitiator (polyethylene glycol, PEG) and subsequently grafted on to PVDF/SMA by alkyne-anhydride reaction. Partially hydrolysed SMA solubilizes membrane proteins and the phosphatase/phospholipase triggers the cleavage of PPE segments resulting in controlled release of Cu ions. This unique strategy renders the membrane surface antibacterial through sustained and controlled release of Cu ions thereby generating intracellular reactive oxygen species (ROS). In addition, the enhanced antibiofouling performance of these membranes is facilitated by the presence of the hydrophilic macroinitiator (PEG and PPE). The modified membranes designed in this study are durable and possess long-term stability due to strong covalent interaction between CuO-PPE and the PVDF/SMA membrane. Studies on the flux, porosity and protein adsorption of the membranes were performed. An enhanced flux recovery ratio was observed for the modified membrane due to the pendant PPE groups (from CuO-PPE) which prohibit irreversible protein adsorption on the PVDF surface. The cytotoxicity of CuO-PPE is greatly reduced because of an effective coverage of CuO by biocompatible PPEs. This study opens up new avenues of fabricating ``smart'' inorganic nanoparticles that can be confined in a soft hybrid polymeric gel network with controlled release of Cu ions thereby precluding ubiquitous bacterial treatment in water filtration systems

Large area solution processed transparent conducting electrode based on highly interconnected Cu wire network

Virtually unlimited and highly interconnected Cu wire networks have been fabricated on polyethylene terephthalate (PET) substrates with sheet resistance of &#60;5 Ω⁻¹ and transmittance of &#8764;75%, as alternatives to the commonly used tin doped indium oxide (ITO) based electrodes. This is a four step process involving deposition of commercially available colloidal dispersions onto PET, drying to induce crackle network formation, nucleating Au or Pd seed nanoparticles inside the crackle regions, washing away the sacrificial layer and finally, depositing Cu electrolessly or by electroplating. The formed Cu wire network is continuous and seamless, and devoid of crossbar junctions, a property which brings high stability to the electrode towards oxidation in air even at 130 &#176;C. The flexible property of the PET substrate is easily carried over to the TCE. The sheet resistance remained unaltered even after a thousand bending cycles. The as-prepared Cu wire network TCE is hydrophobic (contact angle, 80&#176;) which, upon UV–ozone treatment, turned to hydrophilic (&#8764;40&#176;)

Synthesis of a Block Copolymer Exhibiting Cell-Responsive Phytochemical Release for Cancer Therapy

Phytochemicals constitute a promising class of therapeutics for the treatment of various diseases, but their delivery poses significant challenges. In this work, a nanoscale polyactive emulsion was designed for smart, cell-responsive delivery of a curcumin prodrug (curcumin dicarboxylate, CDA) that was chemically conjugated to enzymatically labile oligo-peptides with polycaprolactone (PCL) as the carrier. Matrix metalloproteinase (MMP)-sensitive (PLGLYAL) or nonsensitive (GPYYPLG) peptides were used as spacers for conjugating CDA and PCL. This CDA nanoemulsion incorporating the MMP-sensitive sequence exhibited markedly higher anti-cancer activity, cell internalization, and generation of reactive oxygen species in cancer cells in vitro than the control with the nonsensitive oligopeptide. Moreover, the nanopolyactives induced minimal cytotoxicity in noncancerous cell line. This work presents a unique strategy to engineer smart nano-polyactives for efficient and targeted delivery of phytochemicals