Copper Acetate Monohydrate Research Articles

Long Stability of Atomically Precise Red Emissive Copper Nanoclusters within the Gel and Their Use As a Potential Catalyst and Fluorescent Ink.

Herein, an amphiphile-based hydrogel (with 5% DMF) containing natural amino acid residue has been used to prepare and stabilize red-emitting CuNCs for several months. Though different methods have been attempted, amphiphile and 4-mercaptobenzoic acid (4-MBA)-containing hydrogels are pinpointed to be the base medium to stabilize this new Cu-cluster. From a MALDI-TOF MS analysis it was found that it is a Cu8-atom cluster stabilized by three 4-MBA ligands. Copper acetate monohydrate (Cu(CH3COO)2·H2O) has been used as a copper precursor, and l-ascorbic acid has been used as a reducing agent. FEG-TEM analysis shows that the Cu cluster has an average size of 2.83 nm. Interestingly, these clusters can be used as a fluorescent ink with a visibility of the solid state under a UV-lamp with an excitation of 365 nm. This envisaged applying these CuNCs for anticounterfeiting. These Cu-clusters show an excitation of 420 nm with an emission of 620 nm, as is evident from the fluorescence spectroscopic analysis. Based on our knowledge, this is the first example of making and consequently stabilizing Cu-clusters using hydrogel as a template for a few months. Moreover, these CuNCs can also be used as a catalyst for the reduction of nitro derivatives to their amine derivatives in aqueous medium.

Hybrid Organic-Inorganic Copper and Cobalt Complexes for Antimicrobial Potential Applications

Background/Aims: The naturally occurring phenolic chemical curcumin (CUR), which was derived from the Curcuma longa plant, has a variety of biological actions, including anti-inflammatory, antimicrobial, antioxidant, and anticancer activities. Curcumin is known for its restricted bioavailability due to its hydrophobicity, poor intestinal absorption, and quick metabolism. To boost the biological effects of these bioactive molecules, it is necessary to raise both their bioavailability and their solubility in water. Aim: The aim of this study is to synthesize and characterize hybrid organic-inorganic complexes of copper and cobalt, and to evaluate their antimicrobial potential against a range of pathogenic microorganisms. Methods: The synthesis of metal curcumin complexes (Cu-CUR and Co-CUR) was achieved by mixing curcumin with copper acetate monohydrate. The solid residue was isolated, filtered, and dried in an oven. X-ray diffraction analysis was used to identify the structure and phase of the prepared samples. FTIR spectra were recorded using a Shimadzu 2200 module. The antimicrobial activity of the prepared complexes was evaluated against four bacterial strains and two Candida species. The chemical materials were dissolved in DMSO to a final concentration of 20%, and the plates were incubated at 37°C for 24 hours. The results showed that the prepared complexes had antimicrobial activity against the tested microorganisms. Results: The study compared the Powder X-ray diffraction (XRD) patterns of prepared copper and cobalt complexes to pure curcumin, revealing new, isostructural complexes. The FTIR analysis showed that the Cu-CUR and Co-CUR complexes varied in their inhibitory effect against microorganisms, with Co-CUR being more effective. The results are consistent with previous studies showing the cobalt-curcumin complex was effective against various bacterial genera, with inhibition activity varying depending on the species and strains of microorganisms. Conclusion: Copper and cobalt curcumin complexes, synthesized at room temperature, exhibit high crystallinity and antimicrobial activity. Co-CUR, with its superior antibacterial potential, outperforms pure curcumin in inhibiting microbes. Further investigation is needed to understand their interaction mechanisms with bacteria and fungi.

Effects of Rapid Heat Treatments on the Properties of Cu2O Thin Films Deposited at Room Temperature Using an Ammonia-Free SILAR Technique

We report herein the analysis of the properties of copper(I) oxide thin films deposited by an optimized ammonium-free successive ion layer adsorption and reaction (SILAR) technique. The Cu2O thin film deposition process was carried out at room temperature using copper acetate monohydrate, sodium citrate as complexing agent, and hydrogen peroxide as precursors of copper and oxygen ions, respectively. The harmless and easy-to-handle sodium citrate replaces the volatile NH4OH commonly employed as complexing agent in the SILAR technique for the deposition of metal oxide thin films. The optical, structural, morphological, and electrical properties of the as-deposited Cu2O thin films were studied as a function of the number of cycles during deposition, as well as their modifications produced by the effect of rapid thermal annealing (RTA) in vacuum in a temperature range of 200–250°C for 1 min, 3 min, and 5 min. The as-deposited thin films had cubic crystalline structure corresponding to the Cu2O phase as determined by x-ray diffraction (XRD), with a direct energy bandgap of 2.43–2.51 eV depending on the number of cycles, and electrical resistivity of the order of 103 Ω cm. The XRD and x-ray photoelectron spectroscopy (XPS) analysis of the Cu2O thin films treated by RTA demonstrated an increase of the crystal size with time and temperature of the RTA and reduction effects from Cu2+ to Cu1+ oxidation states. On the other hand, the RTA treatments also decreased their energy bandgap to 2.38 eV and electrical resistivity to 102 Ω cm. The high energy bandgap values of the Cu2O thin films were attributed to quantum confinement effects produced by their small crystal size in the range of 3.6–8.6 nm.Graphical

Click-chemistry mediated synthesis of OTBN-1,2,3-Triazole derivatives exhibiting STK33 inhibition with diverse anti-cancer activities

There is a continuous and pressing need to establish new brain-penetrant bioactive compounds with anti-cancer properties. To this end, a new series of 4′-((4-substituted-4,5-dihydro-1H-1,2,3-triazol-1-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile (OTBN-1,2,3-triazole) derivatives were synthesized by click chemistry. The series of bioactive compounds were designed and synthesized from diverse alkynes and N3-OTBN, using copper (II) acetate monohydrate in aqueous dimethylformamide at room temperature. Besides being highly cost-effective and significantly reducing synthesis, the reaction yielded 91–98 % of the target products without the need of any additional steps or chromatographic techniques. Two analogues exhibit promising anti-cancer biological activities. Analogue 4l shows highly specific cytostatic activity against lung cancer cells, while analogue 4k exhibits pan-cancer anti-growth activity. A kinase screen suggests compound 4k has single-digit micromolar activity against kinase STK33. High STK33 RNA expression correlates strongly with poorer patient outcomes in both adult and pediatric glioma. Compound 4k potently inhibits cell proliferation, invasion, and 3D neurosphere formation in primary patient-derived glioma cell lines. The observed anti-cancer activity is enhanced in combination with specific clinically relevant small molecule inhibitors. Herein we establish a novel biochemical kinase inhibitory function for click-chemistry-derived OTBN-1,2,3-triazole analogues and further report their anti-cancer activity in vitro for the first time.

Nitrile Furanics via Copper‐Catalyzed Dehydration of Aldoximes and Knoevenagel Condensation

AbstractIn this work two synthetic approaches to introduce nitrile moieties into bio‐based derived furanic compounds were investigated, i. e., dehydration of aldoximes and Knoevenagel condensation. Both methodologies have been first tested and optimized on furfural and thus exploited on 5‐hydroxymethyl‐2‐furfural (HMF) and 5,5’‐oxy(bismethylene)‐2‐furaldehyde (OBMF). The syntheses of furfural, HMF and OBMF aldoximes were efficiently conducted (also in large scale) under mild reaction conditions and short reaction time. The subsequent dehydration to nitrile furanic compounds was carried out in the presence of catalytic amount of copper acetate monohydrate. Furthermore, Knoevenagel condensations were performed on furfural, HMF and OBMF with different Activated Methylene Group compounds, using for the first‐time dimethyl carbonate as the reaction media. Most of the resulting products were isolated as pure via simple liquid‐liquid extraction in good to excellent yields. Future applications of these compounds might include aldoxime reduction into amine furanics ‐ herein also preliminary investigated ‐ and hydrolysis of the nitrile derivatives in the related carboxylic acid (or ester) furanics. All these products are interesting monomers for the preparation of bio‐based polymers.

Bipartite entanglement via distance between the states in a one dimensional spin 1/2 dimer copper acetate monohydrate

In this paper, we used a theoretical measure known as distance between the states, , to determine the bipartite entanglement of a one dimensional magnetic dimer system. The calculation was compared with the well-known entanglement measure, concurrence, and found to be the same. was, then, expressed in terms of two thermodynamic quantities, namely, magnetic susceptibility and specific heat. Experimental verification of temperature variation of the bipartite entanglement measure in terms of magnetic susceptibility and specific heat was done on single crystals of copper acetate-an excellent one dimensional dimer system. The results showed the existence of bipartite entanglement till temperatures as high as room temperature! Large sized single crystals of copper acetate were grown by a new evaporation technique and characterised by thermogravimetric analysis, IR and Raman spectroscopy measurements. Density functional theory calculations were done to calculate the delocalisation index which showed much lower values of than other bonds, implying that the probability of direct Cu–Cu exchange in copper acetate is very small. Band structure calculations revealed the presence of flat bands at the Fermi level implying very weak intermolecular interactions in copper acetate.

Broadband EPR Spectroscopy of the Triplet State: Multi-Frequency Analysis of Copper Acetate Monohydrate.

Electron paramagnetic resonance spectroscopy is a long-standing method for the exploration of electronic structures of transition ion complexes. The difficulty of its analysis varies considerably, not only with the nature of the spin system, but more so with the relative magnitudes of the magnetic interactions to which the spin is subject, where particularly challenging cases ensue when two interactions are of comparable magnitude. A case in point is the triplet system S = 1 of coordination complexes with two unpaired electrons when the electronic Zeeman interaction and the electronic zero-field interaction are similar in strength. This situation occurs in the X-band spectra of the thermally excited triplet state of dinuclear copper(II) complexes, exemplified by copper acetate monohydrate. In this study, applicability of the recently developed low-frequency broadband EPR spectrometer to S = 1 systems is investigated on the analysis of multi-frequency, 0.5-16 GHz, data from [Cu(CH3COO)2H2O]2. Global fitting affords the spin Hamiltonian parameters gz = 2.365 ± 0.008; gy = 2.055 ± 0.010; gx = 2.077 ± 0.005; Az = 64 gauss; D = 0.335 ± 0.002 cm-1; E = 0.0105 ± 0.0003 cm-1. The latter two define zero-field absorptions at ca. 630, 7730, and 10,360 MHz, which show up in the spectra as one half of a sharpened symmetrical line. Overall, the EPR line shape is Lorentzian, reflecting spin-lattice relaxation, which is a combination of an unusual, essentially temperature-independent, inverted Orbach process via the S = 0 ground state, and a Raman process proportional to T2. Other broadening mechanisms are limited to at best minor contributions from a distribution in E values, and from dipolar interaction with neighboring copper pairs. Monitoring of a first-order double-quantum transition between 8 and 35 GHz shows a previously unnoticed very complex line shape behavior, which should be the subject of future research.

Cu(II) and Mo(VI) Schiff base complexes immobilized on magnetic multiwalled carbon nanotubes: Oxidation of olefins and theoretical study

In this study, magnetic multiwalled carbon nanotubes (MMWCNT@SiO2) were anchored with phenylene diamine and subsequently prepared as Schiff base through mono condensation with salicylaldehyde, resulting in MMWCNT@SiO2/Schiff base. This was then complexed with either copper acetate monohydrate or molybdenum oxide to form MMWCNT@SiO2/Schiff base/M (M=Cu, MoO2). The prepared samples were characterized with FTIR, EDS, SEM and XRD. The catalytic behavior of the prepared samples was studied in the oxidation reaction. The results revealed that MMWCNT@SiO2/Schiff base/M (M=Cu, MoO2) effectively catalyzed the oxidation reaction of α-methyl styrene leading to more than 99% conversion and selectivity of acetophenone. In addition to the experimental investigations, theoretical calculations were conducted using DFT calculations to provide further insights into the results.

Structural, Morphological, Optical Properties and Impedance Analysis of Solution-Processable Ni-Doped CuO Thin Films on ITO/Glass Substrates

Cupric-oxide-based thin films with various amounts of 0, 1, 2, 3, and 4 wt.% Ni doping were, in turn, deposited on ITO/glass substrates via a solution process. The 0.25 M concentrated solutions of copper (II) acetate monohydrate and nickel acetate tetrahydrate were used as starting materials mixed in ethanol solvent, in order to form the precursors. We obtained that the crystalline structure was not affected by the increase in Ni doping concentration as evidenced by X-ray diffraction patterns. The surface morphology observed by scanning electron microscope pointed out the presence of linked-structure nanoparticles. The influence of Ni doping on the optical bandgap width was evaluated by using ultraviolet-visible spectrometry. We found that the optical bandgap should be direct, and it decreased from 2.69 to 2.38 eV for the range doped. Interestingly, we determined the relaxation time of the Ni-doped CuO/ITO/glass structure from measuring the electrochemical impedance spectroscopy, and it was 0.36 s for the undoped film, then gradually decreased to be 0.31, 0.11, 0.1, and 0.04 s with increasing the Ni doping concentration. This achievement result will serve as a foundation for the future photonic researches.

Design, synthesis, solid-state and solution structures, non linear optical and computational studies of copper(II) complexes supported by variously substituted enantiomerically pure push-pull tetradentate Schiff base ligands

The synthesis, spectroscopic and structural characterization, optical and electrochemical properties and theoretical studies of a family of four new copper(II) complexes supported by a ferrocene-containing N2O2-tetradentate chiral Schiff base ligand derived from enantiomerically pure (1R,2R)-(−)-1,2-diaminocyclohexane are reported. The push-pull Cu(II) complexes were prepared following a one-pot three-component reaction involving the chiral half-unit (1R,2R)-Fc-C(=O)CHC(CH3)NH-c-C6H10NH2, copper acetate monohydrate and the appropriately 3-R,5-R’-substituted salicylaldehyde derivative in a 1:1:1 ratio (Fc = ferrocenyl; 3: R=H, R’ = Cl; 4: R=H, R’ = Br; 5: R=R’ = F;6: R=R’ = NO2), and isolated in 65–97% yields as brown microcrystalline products. The characterization of the synthesized compounds were investigated through CHN elemental analysis, UV–vis, FT-IR, high-resolution mass spectrometry, and X-ray diffraction analysis in the case of the difluoro substituted complex 5 that was obtained in the form of single crystals. It crystallizes in the orthorhombic non-centrosymmetric space group P212121, with two (R,R)-(−)-chiral carbon atoms in the structure. The four-coordinate Cu(II) metal ion adopts a slightly distorted square planar geometry. Magnetic properties of powdered samples have been investigated (2-300 K) and found consistent with a single isolated copper(II) ion (s = 1/2). Cyclic voltammetry showed that the stronger the electron withdrawing effect of the 3,5-substituents, the more anodically shifted the oxidation potential (E1/2) of the ferrocenyl moiety, following the order: 5-Cl < 5-Br < 3,5-F2 < 3,5-(NO2)2. This trend is similar when considering the values of the second-order polarizabilities β of these compounds as measured using Harmonic Light Scattering (HLS) at 1.9 µm, confirming the increasing electron withdrawing effect evidenced by electrochemical studies as well as the conjugation between the electron donor ferrocenyl moiety and the different halogen or nitro substituents through the square planar copper Schiff base framework. Finally, DFT and TD-DFT calculations allow to rationalize the structure and properties of the complexes.

Copper‐Catalyzed Acceptorless Dehydrogenative Coupling of 2‐Aminoaryl Methanols with Nitriles for Accessing Quinazolines and Quinolines

AbstractA copper acetate monohydrate catalyzed simple, effective and economic protocol has been developed for the construction of quinazoline derivatives via acceptorless dehydrogenative coupling of easily available 2‐aminoaryl methanols and nitriles. The methodology was also highly effective for the synthesis of medicinally important quinolines analogues. The reactions proceeded in presence of KOtBu in toluene at 110 °C for 5 h without the requirement of inert condition, external additives and ligands.

Structural, Optical and Ionic Properties of PVA Capped CuS Quantum Dots

Copper sulphide quantum dots were synthesized by a simple chemical route using ammonia (aq.) as a complexing agent in PVA matrix. Copper acetate monohydrate and thiourea were used as precursors. The particle sizes as obtained from XRD results were found to be in good agreement with those of HRTEM. The UV-Vis. absorption and PL emission spectra exhibited a systematic blue shift of absorption and emission respectively confirming quantum confinement effect in the synthesized quantum dots. The band gap as estimated from Tauc-plot increased from 3.26eV to 3.92eV with change of concentration of complexing agent. The FTIR spectra exhibited Cu-S stretching peaks characteristic of CuS. Ionic contributions of the electrolytic ionic CuS solution as measured by a standard conductivity cell clearly showed the semiconducting behavior of the product material. The synthesized material may be exploited in fabrication of an optoelectronic device in UV-blue region.

Synthesis of Spherical Copper Oxide Nanoparticles by Chemical Precipitation Method and Investigation of Their Photocatalytic and Antibacterial Activities

Methylene blue (MB) dye and Staphylococcus aureus (S. aureus) bacteria in wastewater are the two significant problems currently. Researchers have been looking for materials that can combat these two problems at the same time. In the present study, we describe the synthesis of spherical copper oxide (CuO) nanoparticles (NPs) by the chemical precipitation method and evaluate their photocatalytic performance against MB dye and antibacterial efficacy against S. aureus. CuO NPs were produced using copper acetate monohydrate (Cu(CH3COO)2·H2O) as the precursor and sodium hydroxide (NaOH) as the reducing agent. Synthesized CuO NPs were characterized using a combination of techniques, including ultraviolet–visible spectroscopy, X-ray diffraction, transmission electron microscopy, selected area electron diffraction, Fourier transform infrared, and energy-dispersive X-ray diffraction analysis. All the analyses indicated that monoclinic CuO NPs were formed with a spherical shape and an average particle size of 6.2 nm. Photocatalytic experiments indicated that 55.5% of a 10 ppm MB dye solution was degraded by the prepared nano-CuO photocatalyst only after 60 min. Additionally, synthesized CuO NPs demonstrated, to some extent, the zone of inhibition on the S. aureus bacterium’s cell wall. It is inspiring that CuO NPs can be used to solve two problems of MB dye contamination and S. aureus bacterial infection simultaneously.

Self-assembly of Cu-TMA based semiconducting fibrous metallogels for fabrication of active electronic device with high rectification ratio

A stable supramolecular Cu-TMA metallogel was synthesized by using Copper (II) acetate monohydrate and trimesic acid (TMA) as a low molecular weight organic gelator in DMF. The rheological studies confirmed that the synthesized Cu-TMA metallogels have high storage modular. The FT-IR (Fourier-transform infrared spectroscopy) and HR-MS (High Resolution Mass Spectrometry) analysis confirmed the metal–ligand aggregation in the produced metallogels. Apart, FESEM (Field Emission Scanning Electron Microscopy) and TEM (Transmission electron microscopy) probed the shape and morphology of the synthesized supramolecular metallogel like self-assembled fibrous like structure. However, TGA analysis confirmed the high thermal stability of metallogel. To explore the semiconducting properties of metallogel we calculate the energy band gap and, other electrical properties such as current–voltage characteristics and rectifying behaviour for metal–semiconductor (MS) junction-device have been properly investigated. In addition to this, based on the non-linear rectifying behaviour of the device, we have fabricated an active electronic device a Schottky Diode having high Rectification (Ion/Ioff) ratio. Consequently, our synthesized semiconducting Cu-TMA metallogel is fruitful and efficient and could be applied for various other optoelectronic devices in future.

Synthesis of copper nano/microparticles via thermal decomposition and their conversion to copper oxide film.

Copper nano/microparticles were synthesized in octadecene at 290 °C by thermal decomposition method. Copper acetate monohydrate, stearic acid, and 1-octadecanol were used as copper precursor, capping and mild reducing agents, respectively, at the synthesis. Borosilicate glass substrates submerged into the reaction solution during the synthesis were coated by copper nano/microparticles. Thermal decomposition and coating techniques were combined in this study. Copper nano/microparticles were thoroughly characterised via X-ray powder diffraction, X-ray photoelectron, Raman, and attenuated total reflectance-Fourier transform infrared spectroscopies, and scanning and transmission electron microscopies. The average minimum Feret's diameter of these synthesized copper particles was measured as ~87 ± 19 nm. Copper nano/microparticles were converted to copper oxide nano/microparticles by applying heat treatment at 250 °C. The phase composition of copper oxide nano/microparticles was determined by reference intensity ratio analysis. The energy gap of copper oxide nano/microparticles was determined as ~2.33 eV by using Tauc's method. Their band gap PL emission was observed at ~2.15 eV.

Synthesis, Structural, Spectroscopic, Hirshfeld Surface Analysis and Computational Study of Copper Complex Containing Salicylaldimine Ligands

Herein, a new Schiff base copper complex named as of Bis{(E)-5-(diethylamino)-2-(((3-iodo-4-methylphenyl)imino)methyl)phenol}copper(II) ( DIMP- Cu ) is synthesized by the reaction of (E)-5-(diethylamino)-2-(((3-iodo-4-methylphenyl)imino)methyl)phenol with copper(II)acetate monohydrate in ethanol. The complex is characterized by FT-IR, UV-visible, 1 H NMR and 13 C NMR . Moreover, the crystal structure is determined by single crystal X-rays diffraction analysis (SC-XRD) which showed that the coordination geometry around Cu-atom is distorted square planar. The supramolecular assembly is mainly stabilized by CH I bonding. The non-covalent interactions are further inspected by Hirshfeld surface analysis. Mechanical response of the crystal is predicted by void analysis. Computational study is carried out by using HF/3-21G electron density model in order to find the interaction energy between molecular pairs.

Preparation and Photocatalytic Performance of Hollow Spherical TiO2/Cu2O Composites

The anatase phase titanium dioxide sols were prepared by hydrothermal method using titanium sulfate as the titanium source. Copper acetate monohydrate was used as the copper source, cubic phase Cu2O with matched bandgap TiO2 was introduced to synthesize hollow spherical nano-TiO2/Cu2O composites by precipitation method. The powder samples were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area testing (BET), X-ray electron spectroscopy (XPS) and ultraviolet and visible spectrophotometry (UV–Vis) diffuse reflectance spectroscopy analysis using methyl orange (MO) solution as indicator. The results showed that the introduction of Cu2O did not affect the physical phase of TiO2. Titanium dioxide was a shuttle-shaped nanorod with an average particle size less than 20[Formula: see text]nm, Cu2O was a sphere with an average particle size greater than 400 nm. TiO2 loading results in smaller particle size, larger specific surface area, thinner spherical walls, increased hollowness, and improved adsorption and photocatalytic properties of spherical Cu2O. The optimum Ti content of TiO2/Cu2O nanocomposite was 4.0 wt.%, the maximum specific surface area of TiO2/Cu2O sample was 90.57 m2/g with particle size less than 150 nm. When TiO2/Cu2O sample with Ti content of 4.0[Formula: see text]wt.% was used as photocatalyst, the adsorption effect was 66.2% under the dark reaction at 60[Formula: see text]min, the degradation effect was 91.2% under visible light irradiation at 120[Formula: see text]min. The adsorption and photocatalytic performance were excellent when the TiO2/Cu2O sample with Ti content of 4.0[Formula: see text]wt.% was used as the photocatalyst. This work provides an effective method for photocatalytic treatment of waste liquids.

Efficient antibacterial activity in copper oxide nanoparticles biosynthesized via Jasminum sambac flower extract

The objective of the present study is to develop, a hitherto unreported, novel, and sustainable protocol to synthesize copper oxide nanoparticles (CuO NPs) using Jasminum sambac flower extract. CuO NPs of diverse shapes and sizes were obtained using four different copper salt precursors, namely copper sulfate pentahydrate, copper chloride dihydrate, copper nitrate trihydrate, and copper acetate monohydrate while maintaining similar synthetic conditions. XRD analysis reveals that the crystallite sizes of NPs are in the range of 5.25–55.01 nm. FTIR has predicted that biomolecules serve as stabilizing as well as capping agents during the nucleation of NPs. The presence of broad absorption peaks, resulting from surface plasmon resonance, was observed in UV-Vis spectra. The FE-SEM images depicted the diverse morphologies of NPs, which were actually governed by the copper salt precursors. The EDS investigations endorse the dominant peaks corresponding to Cu and O. The analysis of antimicrobial activity was carried out to confirm their aptitude for biomedical applications. It was found that the analogy between the shape of bacteria and that of nanostructure resulted in efficient anti-bacterial activity. The toggle-shaped NPs of CuO derived out of copper sulfate precursor exhibited the best antibacterial activity.

A microfluidic paper-based analytical device for iodometric titration of ascorbic acid and dopamine

A simple, rapid, and on-site iodometric titration with minimal preparation was devised utilizing a novel combination of traditional redox titration and microfluidic paper-based analytical devices (μPADs). The star-shaped pattern titration μPADs consists of a central sample loading zone connected to ten lateral reaction/detection reservoirs. The reaction reservoirs contain various concentrations of copper (II) acetate monohydrate with well-defined concentration gradient intervals and a fixed concentration of potassium iodide. This will result in a gradient of yellow color indicating iodine liberation as titrant in lateral reservoirs. The titration is stimulated when the test solution is applied to the central sample zone. As soon as the sample solution reaches the reaction zones (30 sec. after sample introduction), a constant concentration of amylose solution is added to the detection reservoirs, which serves as an indicator. The analyte is oxidized by the liberated iodine and the excess iodine reacts with amylose indicator, characterized by the formation of dark brownish-blue color. Therefore, the concentrations of target analyte solutions can be determined just in 30 sec., totally instrument-free and directly by naked-eye without calibration. The proposed μPADs are capable of determining ascorbic acid and dopamine solutions ranging from 1.0 × 10−5 M to 1.0 × 10−2 M. The detection lower limit is 1.0 × 10−5 M which is too difficult to measure using conventional volumetric iodometric titration. The reproducibility of the proposed method is lower than ± 5 % for five replicate measurements. The feasibility of the designed μPADs was confirmed by analysis of real samples and the results are highly consonant with those obtained from standard methods.

Dependence of Cu doping on structure, morphology, magnetic and biomedical properties of ZnO nanostructures

We report the dependency of Cu doping on the structure, morphology, magnetic properties and the regulation of cytotoxicity and biocompatibility in macrophages (RAW 264.7) of ZnO nanostructures. A viable chemical bath deposition technique has been explored for the synthesis of undoped and Cu-doped ZnO nanostructures, using the precursor’s mixture of Zinc nitrate hexahydrate, Hexamethylenetetramine and Copper (II) acetate monohydrate. The structural and morphological studies confirms the incorporation of Cu 2+ ion into ZnO matrix hinders the nanorod growth and the nanorod morphology disappears at higher doping. Cu ions substitute Zn 2+ sites in its divalent state as confirmed from X-ray photoelectron spectroscopy studies. Magnetic measurement ensures a dramatic change in the magnetic features due to doping, which is directly reflected in the temperature- and field-dependent magnetization curves. From the cytotoxicity assessment with RAW 264.7 macrophage cell lines, the Cu doped ZnO samples are non-toxic. Our study exhibits the potential usefulness of the materials in spintronic/ magnetic media device applications as well as Cu doping as a promising approach for new functional biomaterials for bio-medical applications.