Poly Diallyldimethylammonium Chloride Research Articles

Avaliação dos testes de compressão da resina acrílica termopolimerizável quando incluído o poli (cloreto de dialildimetilamônio) em sua massa

Introdução: As resinas acrílicas termopolimerizáveis são utilizadas na odontologia de maneira bastante difundida por possuírem diversas propriedades satisfatórias. Esses materiais tendem a sofrer modificações em sua estrutura durante o seu uso podendo causar inflamações e infecções. As mais diversas pesquisas buscaram desenvolver um meio de diminuir essa possibilidade e Dos Santos em 2020 evidenciou que esse material acrescido do biocida poli(cloreto de dialildimetilamônio) tem um potencial antibacteriano e antifúngico, indicando esse acréscimo apenas para próteses que não sofram algum tipo de força durante seu uso. Objetivo: evidenciar o comportamento da resina acrílica termopolimerizada acrescida do poli(cloreto de dialildimetilamônio) frente a testes de compressão buscando avaliar o seu comportamento frente a essa situação. Métodos: Os testes de compressão foram realizados utilizando a maquina de ensaio universal Instron3369 de coluna dupla frente a dois grupos; sendo G1 o material sem a adição do biocida e G2 o material com a adição do biocida. Resultados: Os resultados demonstraram que G2 sofre mais deformação exigindo uma força de compressão menor que G1. Conclusão: Fica evidente que há prejuízos nas propriedades mecânicas da resina acrílica termopolimerizada acrescida do poli(cloreto de dialildimetilamônio), mas que é necessário mais testes para uma futura utilização ou não desse material em diferentes locais.

Coacervation of Spherical Polyelectrolyte Brushes with Additional Polyelectrolytes Bearing Positive or Negative Charges.

By combining small-angle X-ray scattering, wide-angle X-ray scattering, and rheology, the effect of additional polyelectrolyte chains on interactions among spherical polyelectrolyte brushes (SPB) was systematically investigated both on microscopic and macroscopic levels. The negatively charged poly(acrylic acid) (PAA) chains and positively charged poly(dimethyl diallyl ammonium chloride) (PDDA) chains were used as additional polyelectrolyte chains to investigate the local ordered structure and the "polyelectrolyte peak" among SPB. Interestingly, coacervation appeared in the SPB emulsion while introducing additional free polyelectrolyte chains. The addition of excess positively charged PDDA chains would lead to the transformation of the SPB emulsion from the coacervation to the aggregation, while it has not been observed in the case of PAA chains. Moreover, it was further confirmed that the specific local ordered structure was caused by the electrostatic interaction among polyelectrolyte chains of adjacent SPB. This work could enrich our understanding of polyelectrolyte assembly in concentrated SPB, thereby greatly broadening the application fields of SPB.

Azo modified hyaluronic acid based nanocapsules: CD44 targeted, UV-responsive decomposition and drug release in liver cancer cells

Herein, we demonstrate a novel UV-induced decomposable nanocapsule of natural polysaccharide (HA-azo/PDADMAC). The nanocapsules are fabricated based on layer-by-layer co-assembly of anionic azobenzene functionalized hyaluronic acid (HA-azo) and cationic poly diallyl dimethylammonium chloride (PDADMAC). When the nanocapsules are exposed to 365 nm light, ultraviolet photons can trigger the photo-isomerization of azobenzene groups in the framework. The nanocapsules could decompose from large-sized nanocapsules to small fragments. Due to their optimized original size (~180 nm), the nanocapsules can effectively avoid biological barriers, provide a long blood circulation and achieve high tumor accumulation. It can fast eliminate nanocapsules from tumor and release the loaded drugs for chemotherapy after UV-induced dissociation. Besides, HA is an endogenous polysaccharide that shows intrinsic targetability to CD44 receptors on surface of cancer cells. The intracellular experiment shows that the HA-azo/PDADMAC nanocapsules with CD44 targeting ability and UV-controlled intracellular drug release are promising for cancer chemotherapy.

Adsorptive Removal of Anionic Azo Dye New Coccine Using Silica and Silica-gel with Surface Modification by Polycation.

In the present work, adsorption of anionic azo dye, new coccine (NCC) on silica and silica-gel in an aquatic environment was discovered. Effective conditions such as adsorption time, pH, the influence of dosage on NCC adsorption using strong polycation, poly-diallyl-dimethylammonium chloride (PDADMAC) modified silica (PMS) and PDADMAC modified silica-gel (PMSG) were systematically studied. The removal of NCC using PMS and PMSG were much higher than that using raw silica and silica-gel without PDADMAC in all pH ranges from 3 to 10. The adsorption of NCC onto PMS and PMSG was achieved maxima at the same conditions of contact time 30 min, pH 6. The optimum adsorbent dosages of PMS and PMSG for NCC removal were 10 and 20 mg·mL−1, respectively. Experimental results of NCC adsorption isotherms onto PMS and PMSG at different ionic strength were fitted by Langmuir and Freundlich models. The NCC removal efficiencies using PMS and PMSG were higher than 87%, indicating that PMS and PMSG are novel and reusable adsorbents for removal of anionic dye. Based on adsorption isotherms, and surface group changes after PDADMAC modification and NCC adsorption examined by Fourier transform infrared spectroscopy (FTIR), we demonstrate that electrostatic interaction between positively charged adsorbents’ surfaces and negative sulfonic groups of NCC are the main driving force for anionic azo dye adsorption onto PMS and PMGS adsorbents.

Synthesis and Rheological Properties of Magnetic Chitosan Hydrogel

The aim of the present work is first to synthesis a magnetic chitosan hydrogel (chitosan ferrogel) using the blending method and second to study it rheological behavior. Magnetic components ( maghemite particles γ-Fe2O3 ) were synthesized via a simple chemical co-precipitation route also called Massart's procedure. Before being dispersed in chitosan network, γ-Fe2O3 particles were covered with a cationic polyelectrolyte (Polydiallyldimethylammonium chloride; PDADMAC) and the exact quantity required to cover the entire surface of maghemite particles was determined by Electrophoretic mobility. The successful functionalization of maghemite particles was confirmed by zeta potential measurement. The prepared ferrogel was gelified using glyoxal as crosslinking agent. The effect of continuous magnetic field on rheological properties of the elaborated ferrogel was studied, under controlled temperature before and after the gelation process, using a rotating rheometer fitted with a new magneto-rheological cell. Moreover the influence of iron oxide content on the gelation time of magnetic hydrogel was studied by comparing two ferrogels with different maghemite particles content. Flow and viscoelastic measurements showed that applying magnetic field facilitates the formation of a new structure (column-like arrangements), which was confirmed by in situ optical microscopic observation. Kinetic study was investigated by mechanical spectroscopy and demonstrates that the gelation time depends on both iron oxides content and magnetic field.

Viscosity of Polyelectrolyte Surfactant Complexes—The Importance of the Choice of the Polyelectrolyte Seen for the Case of PDADMAC Versus JR 400

Some oppositely charged polyelectrolyte (PE) surfactant mixtures show a remarkable increase in viscosity near charge equilibrium, while other very similar systems do not show any appreciable effect. The exact structural prerequisites to achieve a significant increase in viscosity are still unclear. In previous work, we investigated the structure and dynamics of oppositely charged polyelectrolyte surfactant complexes (PESCs) formed from sodium dodecylsulfate (SDS) and the cationically modified hydroxyethyl cellulose JR 400, which does enhance the viscosity around charge equilibrium enormously. Here, we study PESCs consisting of SDS and the cationic PE polydiallyldimethylammonium chloride (PDADMAC) which do not significantly increase the viscosity of solutions under similar conditions. Apparently very similar ingredients in PESCs can lead to largely different macroscopic behavior. Using small-angle neutron scattering, rheology, and neutron spin-echo spectroscopy, we gain insights into the system’s mesoscopic structure and dynamics. Different from that in SDS/JR 400, no intermixed aggregates are formed but instead a cylindrical core–shell structure. In it, the PDADMAC is much less strongly bound and possesses much higher dynamics which explains the much lower viscosity.

Effect of the composition stoichiometry and salt on the ammonia sensing properties of curcumin-loaded polyelectrolyte complex membranes

Nonstoichiometric polyelectrolyte complex (PEC) membranes loaded with natural colorimetric indicator 1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin, Cur) were used as visual detectors for ammonia (NH3) vapors. PEC membranes were fabricated by the co-precipitation of cationic poly(diallyldimethylammonium chloride) (PDADMAC) and anionic poly(sodium 4-styrene sulfonate) (PSS) using NaCl as a plasticizer followed by centrifugation and compression molding into 120-micron sheets. The polymer complex (PEC) was prepared using various molar ratios of PDADMAC and PSS [P+]/[P−] of [2:1], [1:1] and [1:2] which color response when exposed to ammonia vapor shifted from yellow to orange-red. The fast color change was clearly observed by naked eyes and confirmed by UV–Vis spectroscopy. The main finding of this paper is that the PDADMAC-rich membrane with a [P+]/[P−] of [2:1] displayer better NH3 sensing and that different salts used in the processing of the PEC can improve the sensitivity of the sensors by increasing the moist content in the membranes. The reversible color change to yellow was possible at ambient temperature when the ammonia vapor was removed making these sensors reusable. These Cur-PEC membranes could be used in sensing applications to monitor the release of NH3 gas from industrial sites by optical detection.

Integration of Forward Osmosis Membrane Bioreactor (FO-MBR) and Membrane Distillation (MD) units for water reclamation and regeneration of draw solutions

In the current lab scale study, the two treatment technologies of FO (Forward osmosis) and DCMD (Direct contact membrane distillation) were used in combination to create a continuous treatment system for water reclamation using, inorganic NaCl, surfactant (Tetraethyl ammonium bromide, TEAB) and polyelectrolyte (Polydiallyldimethylammonium chloride, PDAC) as FO draw solutes with both DI water (FO-MD), and monoculture municipal synthetic wastewater with Bacillus subtillis inoculum as feed (FOMBR-MD).Each of the units was optimized separately at bench scale, and then combined to form a Forward Osmosis Membrane Bioreactor – Membrane Distillation (FOMBR-MD) hybrid for water reclamation from wastewater. In this hybrid system, the diluted draw solution was fed to the MD unit for reconcentration. The MD unit was tested at various operating temperatures; for FO-MD, a temperature difference of 15 °C was chosen, with a feed temperature of 35 °C and a permeate temperature of 20 °C. For the FOMBR, the temperature difference was increased to 25 °C. When the cross flow velocity was kept constant, the MD flux increased significantly with increasing temperature. Low grade waste heat from industry can potentially be utilised for the FO-MD process. The increase in flux was higher for NaCl and TEAB (60–80 %) when compared to PDAC (20–50 %), as the temperature difference increased to 35 °C. A greater feed flow velocity increased the turbulence in the flow channel, and increased the MD flux. Up to a 60 % increase in flux was observed when the feed velocity was increased from 0.12 to 0.17 m/s, while the increase in flux was not as high when the flow was increased from 0.17 to 0.21 m/s and thus 0.17 m/s was chosen as the cross- flow velocity for MD. Higher feed concentrations tended to reduce vapour pressures and hence decreased the MD water fluxes.The flux for FO-MBR and MD were well balanced for lower molecular weight draw solutes, but lower FO fluxes were observed for higher molecular weight draw solutes (TEAB, PDAC). This greater imbalance reflected their lower diffusivities and greater tendencies toward concentration polarization. Reverse solute transport (RST) values leading to salinity or toxicity were not reflected by the observations, and therefore it was feasible to run an FOMBR-MD Hybrid for extended times. However, a greater decline in flux versus time was observed for NaCl than for TEAB. PDAC showed the lowest but most stable flux, and a lesser fouling tendency compared to that of TEAB. Overall, The FO-MD hybrid enabled pure water production and a non-volatile component rejection of nearly 99 %, with an RST of <0.1 GMH for the draw solutions back to the FO feed and a much lower solute transport from the MD feed to the permeate. NaCl and other low molecular weight solutes are recommended when high fluxes and system stability are priorities and where high reverse solute transport (RST), leading to salinity or solute toxicity in the MBR feed tank, is not an issue. Higher molecular weight solutes, such as TEAB or PDAC, are recommended when high flux is less critical and when the sensitivity of the microbial consortium to RST and solute toxicity is a concern. In all cases, some degree of process control is recommended in order to bring the systems more quickly to a stable operating state; periodic membrane cleaning is deemed necessary to maintain this state.

Structure of polymer-capped gold nanorods binding to model phospholipid monolayers

We report an experimental study of the structure of polymer-capped gold nanorods (AuNRs) binding to model phospholipid monolayers to elucidate the mechanism that drives the insertion of the AuNRs into phospholipid membranes. The experimental system consists of four different cases of AuNRs interacting with lipid monolayers: cationic and anionic polymer-capped AuNRs suspended in the pure water subphase of Langmuir monolayers of zwitterionic and anionic phospholipids, separately. Liquid surface x-ray reflectivity was used to measure in situ the structure of the lipids and AuNRs at the air-water interface with sub-nanometer resolution, yielding quantitatively the amount, orientation, as well as depth of AuNR insertion into the monolayer. In the case of a zwitterionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine, cationic Poly-diallyldimethylammonium chloride (PDC) capped AuNRs (PDC-AuNRs) adsorbed peripherally at the water-lipid interface whereas the anionic Poly-sodium 4-styrenesulfonate (PSS) capped AuNRs (PSS-AuNRs) penetrated deeply into the lipid monolayer. In the case of an anionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (SOPG), PDC-AuNRs inserted into the monolayer whereas PSS-AuNRs were not even attracted to the monolayer. The results suggest that the adsorption process of AuNRs to model membranes may proceed through different mechanisms. In the presence of a charged membrane, electrostatic interactions drove the AuNRs to or away from the membrane depending on the nature of the charge of the lipid film and the AuNRs, while in the presence of a zwitterionic membrane, both electrostatic interactions and hydrophobic interactions mediated the insertion of the AuNRs into the membrane.

A Fluidics-Based Biosensor to Detect and Characterize Inhibition Patterns of Organophosphate to Acetylcholinesterase in Food Materials.

A chip-based electrochemical biosensor is developed herein for the detection of organophosphate (OP) in food materials. The principle of the sensing platform is based on the inhibition of dimethoate (DMT), a typical OP that specifically inhibits acetylcholinesterase (AChE) activity. Carbon nanotube-modified gold electrodes functionalized with polydiallyldimethylammonium chloride (PDDA) and oxidized nanocellulose (NC) were investigated for the sensing of OP, yielding high sensitivity. Compared with noncovalent adsorption and deposition in bovine serum albumin, bioconjugation with lysine side chain activation allowed the enzyme to be stable over three weeks at room temperature. The total amount of AChE was quantified, whose activity inhibition was highly linear with respect to DMT concentration. Increased incubation times and/or DMT concentration decreased current flow. The composite electrode showed a sensitivity 4.8-times higher than that of the bare gold electrode. The biosensor was challenged with organophosphate-spiked food samples and showed a limit of detection (LOD) of DMT at 4.1 nM, with a limit of quantification (LOQ) at 12.6 nM, in the linear range of 10 nM to 1000 nM. Such performance infers significant potential for the use of this system in the detection of organophosphates in real samples.

Application of synthetic and grafted polymeric flocculants in agricultural wastewater treatment

Due to the large amounts of freshwater consumed in Egypt by the agricultural sector that is more than 85% of Egypt share of freshwater in addition to the high concentrations of salts, chemicals and nutrients produced from fertilizers. Reduction of these pollutants concentrations to an acceptable level and breaking the sedimentation stability of colloidal substances and organic particles for reuse for irrigation purposes was associated with the application of biological treatment with coagulants addition. The flocculation process was performed by using polydiallyldimethylammonium chloride (polyDADMAC) and polyacrylamide grafted oatmeal (OAT-g-PAM). The scale-pilot consists of an aeration tank equipped with an air blower, sedimentation tank followed by a filtration stage through 20 cm of pottery scrubs media. To study the performance of synthetic and grafted polymeric flocculants, 3 trials were performed. Activated sludge process without adding any polymeric flocculants was the control trial. In the second trial, polyDADMAC was added with a dose of 5 mg/l. Finally, OAT-g-PAM with a dose of 1.25 mg/l was used in the third trial. The physicochemical properties of agricultural wastewater were measured at the national research center in Cairo. It was found that OAT-g-PAM incorporated with activated sludge process was the most effective in treating agricultural wastewater as it achieved COD, BOD,TKN, TP, and TSS removal efficiency up to 92.29%, 93.13%, 90.64%, 90.46%, and 92.5%, respectively which made it suitable to reuse for agricultural purposes, in addition to its ability to biodegrade, environmentally friendly, and low dosage required compared to polyDADMAC.

Carbon-doped titanium dioxide nanoparticles for visible light driven photocatalytic activity

This work reports tuning of the band gap of the titanium dioxide (TiO2) nanoparticles by carbon doping during sol-gel synthesis. Herein, polydiallyldimethylammonium chloride (PDADMAC), a cationic polymer has been used as the carbon source. The band gap, microstructure and the phase of the synthesized TiO2 can be engineered by controlling the concentration of PDADMAC. A significant reduction in the band gap energy from 2.96 eV to 2.37 eV was observed upon carbon doping. Phonon Confinement Model was employed to investigate the material properties. Theoretical calculations based on Density Functional Theory have also suggested the reduction of band gap as a result of significant interaction between carbon, titanium and oxygen atoms in the lattice. These studies have also proved that structural modifications also occurred due to doping of carbon atom in TiO2 nanomaterial. Carbon-doping resulted in a more efficient photocatalytic activity of the TiO2 nanoparticles. The kinetics and thermodynamics of photodegradation of methylene blue was investigated in detail.

Core-shell structure Co–Ni@Fe–Cu doped MOF–GR composites for water splitting

What is essential to solving energy scarcity problems is that develop the high activity, durable and non-noble metal-based dual-functional electrocatalysts for hydrogen evolution reactions (HER) and oxygen evolution reactions (OER). In this work, a series of core-shell structure M@Fe–Cu-GR nanocubes (NCs) are prepared. In the prepared process, the bimetallic FeCu prussian blue analogues (PBA) is used as precursor, transition metals ions Co2+ and Ni2+ are introduced into the FeCu-PBA using the exchange of potassium ions with other metal ions, and then the FeCu-PBA are successfully loaded on the graphene oxide (GO) employed the attraction of opposite charges between polydiallyldimethylammonium chloride (PDDA) and GO. Electrochemical tests show that the Tafel slope of Co–Ni@Fe–Cu–GR NCs for HER and OER are 60 and 82 mV dec−1, respectively, and Co–Ni@Fe–Cu–GR NCs shows excellent performance in long-term stability test.

In-fiber optofluidic online SERS detection of trace uremia toxin.

In this Letter, we propose a microstructured in-fiber optofluidic surface-enhanced Raman spectroscopy (SERS) sensor for the initial inspection of uremia through the detection of unlabeled urea and creatinine. As a natural microfluidic device, microstructured hollow fiber has a special structure inside. Through chemical bonds, the SERS substrate can be modified and grown on the surface of the suspended core. Here, the silver nanoparticles (Ag NPs) are embedded on the poly diallyl dimethyl ammonium chloride-modified graphene oxide sheet to achieve the self-assembled SERS substrate. The reduced distance between Ag NPs can increase the strong hot spots that generate enhanced Raman signals. Therefore, it can effectively detect the Raman signal of unlabeled trace uremic toxin analytes (urea, creatinine) inside the optical fiber. The results show that under simulated biophysical conditions, the limit detection (LOD) for urea is 10-4M and the linearity is good, especially at the clinical conventional concentration range (2.5-6.5×10-3M). In addition, the online Raman detection of creatinine aqueous solution LOD is 10-6M, which also has good linearity. Significantly, this Letter provides a microstructured optofluidic in-fiber Raman sensor for the preliminary detection of uremia, which will have good development prospects in the field of clinical biomedicine.

Model Surfaces for Paper Fibers Prepared from Carboxymethyl Cellulose and Polycations.

For tailored functionalization of cellulose based papers, the interaction between paper fibers and functional additives must be understood. Planar cellulose surfaces represent a suitable model system for studying the binding of additives. In this work, polyelectrolyte multilayers (PEMs) are prepared by alternating dip-coating of the negatively charged cellulose derivate carboxymethyl cellulose and a polycation, either polydiallyldimethylammonium chloride (PDADMAC) or chitosan (CHI). The parameters varied during PEM formation are the concentrations (0.1–5 g/L) and pH (pH = 2–6) of the dipping solutions. Both PEM systems grow exponentially, revealing a high mobility of the polyelectrolytes (PEs). The pH-tunable charge density leads to PEMs with different surface topographies. Quartz crystal microbalance experiments with dissipation monitoring (QCM-D) reveal the pronounced viscoelastic properties of the PEMs. Ellipsometry and atomic force microscopy (AFM) measurements show that the strong and highly charged polycation PDADMAC leads to the formation of smooth PEMs. The weak polycation CHI forms cellulose model surfaces with higher film thicknesses and a tunable roughness. Both PEM systems exhibit a high water uptake when exposed to a humid environment, with the PDADMAC/carboxymethyl cellulose (CMC) PEMs resulting in a water uptake up to 60% and CHI/CMC up to 20%. The resulting PEMs are water-stable, but water swellable model surfaces with a controllable roughness and topography.

Influence of polyelectrolytes on increasing sensitivity of an immunofluorescent analysis based on plasmon silver nanoparticles

It was studied the dependence of the interaction of the components of the immunofluorescence test system for the quantitative determination of prostate specific antigen based on plasmon silver nanoparticles on the physicochemical nature of various polyelectrolytes used to coat films of silver nanoparticles. It has been shown that the use of a weakly charged polycationic polyelectrolyte poly-L-lysine can increase the antigenic binding of the test system by 2.34 times, and the use of a highly charged polycationic polyelectrolyte polydiallyldimethylammonium chloride increases the binding affinity of prostatic specific antigen by 5 times. When developing various immunochemical test systems using films of silver nanoparticles, an important parameter is the choice of a polyelectrolyte for coating a silver nanolayer, since the physicochemical and electrostatic properties of the polyelectrolyte can significantly affect both the sorption capacity of the solid phase and the conformational state functional activity of immobilized protein molecules. Both specificity and sensitivity of the immunochemical test system, as well as the minimum possible detectable concentration of bioanalyte, largely depend on these parameters.

A Bio-Inspired Nanotubular Na2MoO4/TiO2 Composite as a High-Performance Anodic Material for Lithium-Ion Batteries.

A train of bio-inspired nanotubular Na2MoO4/TiO2 composites were synthesized by using a natural cellulose substance (e.g., commercial ordinary filter paper) as the structural template. The TiO2 gel films were coated on the cellulose nanofiber surfaces via a sol-gel method firstly, followed with the deposition of the poly(diallyldimethylammonium chloride)/Na2MoO4 (PDDA/Na2MoO4) bi-layers several times, through the layer-by-layer self-assembly route, yielding the (PDDA/Na2MoO4)n/TiO2-gel/cellulose composite, which was calcined in air to give various Na2MoO4/TiO2 nanocomposites containing different Na2MoO4 contents (15.4, 24.1, and 41.4%). The resultant nanocomposites all inherited the three-dimensionally porous network structure of the premier cellulose substance, which were formed by hierarchical TiO2 nanotubes anchored with the Na2MoO4 layers. When employed as anodic materials for lithium-ion batteries, those Na2MoO4/TiO2 nanocomposites exhibited promoted electrochemical performances in comparison with the Na2MoO4 powder and pure TiO2 nanotubes, which was resulted from the high capacity of the Na2MoO4 component and the buffering effects of the TiO2 nanotubes. Among all the nanotubular Na2MoO4/TiO2 composites, the one with a Na2MoO4 content of 41.4% showed the best electrochemical properties, such as the cycling stability with a capacity of 180.22 mAh g−1 after 200 charge/discharge cycles (current density: 100 mA g−1) and the optimal rate capability.

Electrochemical aptasensor for ultrasensitive detection of lipopolysaccharide using silver nanoparticles decorated titanium dioxide nanotube/functionalized reduced graphene oxide as a new redox nanoprobe.

Anovel and relatively simple signal-off electrochemical aptasensor was constructed for highly sensitive detection of lipopolysaccharide (LPS). For the first time, silver nanoparticles (AgNPs) decorated titanium dioxide nanotube (TNT) was conjugated with polydiallyldimethylammonium chloride (PDDA) functionalized reduced graphene oxide (rGO) to form a new nanohybrid of Ag-TNT/P-rGO. This nanohybrid with a large specific surface area exhibited excellent electrochemical activity, which not only served as the sensing platform to immobilize LPS binding aptamer (LBA) but wasalso employed as the redox probe to monitor the change of the electrochemical signal. The electrochemical signal responses were measured by cyclic voltammetry (CV) in the potential range-0.3 to 0.5V at a scan rate of 0.1V/s. The proposed aptasensor exhibited acceptable stability, reproducibility, and specificity for LPS detection with a wide linear range from 17fg/mL to 100ng/mL. Thelimit of detection (LOD) was 5fg/mL. Furthermore, the prepared aptasensor showed acceptable recovery ranging from 96% to 103%, and the RSD varied between 1.4% and 8.5% for determining LPS in real samples.Graphical abstract.

Preparation of Ultra-Thin Sandwich Cu-Cu/CNTs-Cu Composite Foil With High Tensile Strength by Electrodeposition

Cu/CNTs composites have drawn considerable attention owing to their excellent properties such as high tensile strength and strong electrical conductivity. In this paper, the effect of CNTs on the properties of copper foil is deeply investigated. The surface of CNTs was positively charged by cationic surfactant poly diallyldimethylammonium chloride (PDDA), then CNTs were introduced into the copper matrix under the joint action of chloride ion (Cl-) and sodium 3-mercapto-1-propanesulfonate (MPS). Ultra-thin sandwich Cu-Cu/CNTs-Cu composite foil with high tensile strength is prepared by electrodeposition, and characterized by XRD, EBSD, SEM, TEM, universal testing machine, instrumental nanoindenter and so on. In comparison with pure copper foil, its tensile strength reaches 582 GPa, increased by 62.0% and its elastic modulus is 97.5 GPa, increased by 14.3%, and its hardness is 2.38 GPa, increased by 8.7%. Our research provides a new way for exploring high tensile strength composite copper foil.

Polydimethyldiallylammonium Chloride Stifles Sludge Anaerobic Digestion: Key Role of Quaternary Amine Groups

Polydimethyldiallylammonium Chloride Stifles Sludge Anaerobic Digestion: Key Role of Quaternary Amine Groups