Magnetic Silica‐Coated Sub‐Microspheres with Immobilized Metal Ions for the Selective Removal of Bovine Hemoglobin from Bovine Blood

Magnetic silica‐coated magnetite (Fe₃O₄) sub‐microspheres with immobilized metal‐affinity ligands are prepared for protein adsorption. First, magnetite sub‐microspheres were synthesized by a hydrothermal method. Then silica was coated on the surface of Fe₃O₄ particles using a sol–gel method to obtain magnetic silica sub‐microspheres with core‐shell morphology. Next, the trichloro(4‐chloromethylphenyl) silane was immobilized on them, reacted with iminodiacetic acid (IDA), and charged with Cu²⁺. The obtained magnetic silica sub‐microspheres with immobilized Cu²⁺ were applied for the absorption of bovine hemoglobin (BHb) and the removal of BHb from bovine blood. The size, morphology, and magnetic properties of the resulting magnetic micro(nano) spheres were investigated by using scanning microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and a vibrating sample magnetometer (VSM). The measurements showed that the magnetic sub‐microspheres are spherical in shape, very uniform in size with a core‐shell, and are almost superparamagnetic. The saturation magnetization of silica‐coated magnetite (Fe₃O₄) sub‐microspheres reached about 33 emu g^?1. Protein adsorption results showed that the sub‐microspheres had a high adsorption capacity for BHb (418.6 mg g^?1), low nonspecific adsorption, and good removal of BHb from bovine blood. This opens a novel route for future applications in removing abundant proteins in proteomic analysis.     

Template‐Free Synthesis and Mechanistic Study of Porous Three‐Dimensional Hierarchical Uranium‐Containing and Uranium Oxide Microspheres

A novel type of uranium‐containing microspheres with an urchin‐like hierarchical nano/microstructure has been successfully synthesized by a facile template‐free hydrothermal method with uranyl nitrate hexahydrate, urea, and glycerol as the uranium source, precipitating agent, and shape‐controlling agent, respectively. The as‐synthesized microspheres were usually a few micrometers in size and porous inside, and their shells were composed of nanoscale rod‐shaped crystals. The growth mechanism of the hydrothermal reaction was studied, revealing that temperature, ratios of reactants, solution pH, and reaction time were all critical for the growth. The mechanism study also revealed that an intermediate compound of 3 UO₃?NH₃?5 H₂O was first formed and then gradually converted into the final hydrothermal product. These uranium‐containing microspheres were excellent precursors to synthesize porous uranium oxide microspheres. With a suitable calcination temperature, very uniform microspheres of uranium oxides (UO_2+x, U₃O₈, and UO₃) were successfully synthesized.     

Preparation of core–shell structure Fe3O4@SiO2 superparamagnetic microspheres immoblized with iminodiacetic acid as immobilized metal ion affinity adsorbents for His‐tag protein purification

The core–shell structure Fe₃O₄/SiO₂ magnetic microspheres were prepared by a sol–gel method, and immobiled with iminodiacetic acid (IDA) as metal ion affinity ligands for protein adsorption. The size, morphology, magnetic properties and surface modification of magnetic silica nanospheres were characterized by various modern analytical instruments. It was shown that the magnetic silica nanospheres exhibited superparamagnetism with saturation magnetization values of up to 58.1 emu/g. Three divalent metal ions, Cu²⁺, Ni²⁺ and Zn²⁺, were chelated on the Fe₃O₄@SiO₂–IDA magnetic microspheres to adsorb lysozyme. The results indicated that Ni²⁺‐chelating magnetic microspheres had the maximum adsorption capacity for lysozyme of 51.0 mg/g, adsorption equilibrium could be achieved within 60 min and the adsorbed protein could be easily eluted. Furthermore, the synthesized Fe₃O₄@SiO₂–IDA–Ni²⁺ magnetic microspheres were successfully applied for selective enrichment lysozyme from egg white and His‐tag recombinant Homer 1a from the inclusion extraction expressed in Escherichia coli. The result indicated that the magnetic microspheres showed unique characteristics of high selective separation behavior of protein mixture, low nonspecific adsorption, and easy handling. This demonstrates that the magnetic silica microspheres can be used efficiently in protein separation or purification and show great potential in the pretreatment of the biological sample. Copyright © 2015 John Wiley & Sons, Ltd.     

Nanoscale Metal–Organic Framework–Hemoglobin Conjugates

A metal–organic framework (MOF)–protein conjugate, NH₂‐MIL‐125(Ti)‐hemoglobin [MIL‐125(Ti)‐Hb], was synthesized by a covalent postmodification strategy. The crystalline structure was maintained after chemical and protein modification. The content of grafted Hb was tuned by the stoichiometric ratio and reached 50 wt % if the mass ratio of MIL‐125(Ti)/Hb was 1:1.25 in the feed. The oxygen‐transporting capacity of grafted Hb was kept, and the P₅₀ (the half O₂ pressure saturated with O₂) and Hill coefficients of the MIL‐125(Ti)‐Hb conjugate were found to be 22.9 mm Hg and 2.35, respectively, which are close to the respective values of free Hb. All the results indicate that the MIL‐125(Ti)‐Hb conjugate could be potentially used as an oxygen carrier.     

Hydroxyapatite Hierarchically Nanostructured Porous Hollow Microspheres: Rapid,Sustainable Microwave‐Hydrothermal Synthesis by Using Creatine Phosphate as an Organic Phosphorus Source and Application in Drug Delivery and Protein Adsorption

Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave‐assisted hydrothermal method. The as‐obtained products are characterized by powder X‐ray diffraction (XRD), Fourier‐transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer–Emmett–Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8–1.5 μm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m²g^?1 and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant‐free and environmentally friendly. The as‐prepared HAP porous hollow microspheres show a relatively high drug‐loading capacity and protein‐adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as‐prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption.     

A Facile Method for Preparing Porous,Optically Active,Magnetic Fe3O4@poly(N‐acryloyl‐leucine) Inverse Core/Shell Composite Microspheres

The first synthesis of porous, optically active, magnetic Fe₃O₄@poly(N‐acryloyl‐leucine) inverse core/shell composite microspheres is reported, in which the core is constructed of chiral polymer and the shell is constructed of Fe₃O₄ NPs. The microspheres integrate three significant concepts, “porosity”, “chirality”, and “magneticity”, in one single microspheric entity. The microspheres consist of Fe₃O₄ nanoparticles and porous optically active microspheres, and thus combine the advantages of both magnetic nanoparticles and porous optically active microspheres. The pore size and specific surface area of the microspheres are characterized by N₂ adsorption, from which it is found that the composite microspheres possess a desirable porous structure. Circular dichroism and UV‐vis absorption spectroscopy measurements demonstrate that the microspheres exhibit the expected optical activity. The microspheres also have high saturation magnetization of 14.7 emu g^–1 and rapid magnetic responsivity. After further optimization, these novel microspheres may potentially find applications in areas such as asymmetric catalysis, chiral adsorption, etc.

     

Vapor‐Surface Sol‐Gel Deposition of Titania Alternated with Protein Adsorption for Assembly of Electroactive,Enzyme‐Active Films

Combining vapor‐surface sol‐gel deposition of titania with alternate adsorption of oppositely charged iron heme proteins provided ultrathin {TiO₂/protein}_n films with reversible voltammetry extended to 15 TiO₂/protein bilayers, more than twice that of more conventional polyion‐protein or nanoparticle‐protein films made by alternate layer‐by‐layer adsorption. Catalytic activity toward O₂, H₂O₂, and NO was also improved significantly compared to the conventionally fabricated films. The method involves vaporization of titanium butoxide into thin films of water, forming porous TiO₂ sol‐gel layers. Myoglobin (Mb), hemoglobin (Hb), and horseradish peroxidase (HRP) were assembled by adsorption alternated with the vapor‐deposited TiO₂ layers. Improved electrochemical and catalytic performance may be related to better film permeability leading to better mass transport within the films, as suggested by studies with soluble voltammetric probes, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical and electrocatalytic activity of the films can be controlled by tailoring the amount of water with which the metal alkoxide precursor vapor reacts and the number of bilayers deposited in the assembly.     

Cooperative Capture of Uranyl Ions by a Carbonyl‐Bearing Hierarchical‐Porous Cu–Organic Framework

To efficiently capture the toxic uranyl ions (UO₂²⁺), a new hierarchical micro‐macroporous metal–organic framework was prepared under template‐free conditions, featuring interconnected multi‐nanocages bearing carbonyl groups derived from a semi‐rigid ligand. The material exhibits an unusually high UO₂²⁺ sorption capacity of 562 mg g^?1, which occurs in an intriguing two‐steps process, on the macropore‐based crystal surface and in the inner nanocages. Notably, the latter is attributed to the cooperative interplay of the shrinkage of the host porous framework induced by uranyl accommodation and the free carbonyl coordination sites, as shown by both single‐crystal X‐ray diffraction and a red‐shift of the infrared [O=U^VI=O]²⁺ antisymmetric vibration band.     

Estimation of radiological indices in Indian Sundarbans: a mangrove habitat

Stereoscopic porous microspheres based gellan gum (GG–Ca) were successfully prepared by sol–gel method using ethyl acetate as porogen and glutaraldehyde as crosslinker. The obtained GG–Ca microspheres were mainly of mesoporous with the average pore diameter was about 4 nm. It displayed a higher ability for uranium removal. In addition, the uranium adsorption process was endothermic and spontaneous following a pseudo-second-order and the adsorption isotherm was the best fit with the Freundlich model with maximum uranium capacity of 202.26 mg g⁻¹. The UO²⁺ adsorption mechanism is ion-exchange with Ca²⁺ based on SEM, EDX and XPS data analysis.

     

Ceramic Filter Balls Loaded with α-Fe2O3 and Their Application to NH3-N Wastewater Treatment

Hydrolysis reaction of Fe(NO₃)₃ at a high temperature in the presence of urea as the homogeneous precipitant was studied. With the prepared ceramic filter balls loaded with α-Fe₂O₃ after high temperature calcination, the loading of α-Fe₂O₃ on the porous ceramic filter balls from Fe(NO₃)₃ solutions of different concentrations and mechanical stability of the loaded α-Fe₂O₃ were studied. The product was characterized using XRD and SEM. Adsorption experiments were conducted to evaluate the performance of the product in adsorbing NH₃-N. It turned out that the specific surface area of the ceramic filter balls loaded with α-Fe₂O₃ had increased to 36.5387 m²/g from original 4.6127 m²/g. When the concentration of Fe(NO₃)₃ was 0.40 mol/L, the loading of α-Fe₂O₃ on the ceramic filter balls accounted for 8.4% of the total mass of the adsorbent and α-Fe₂O₃ was adsorbed on the filter balls very well. The adsorption isotherm of NH₃-N on the ceramic filter ball adsorbent loaded with α-Fe₂O₃ was of Langmuir type. The saturated adsorption capacity was 3.33 mg/L, and the adsorption constant K was 0.1873. NH₃-N was adsorbed by α-Fe₂O₃ more easily, which was a kind of specific adsorption.     

Electrochemistry and Electrocatalysis of Hemoglobin on 1‐Pyrenebutanoic Acid Succinimidyl Ester/Multiwalled Carbon Nanotube and Au Nanoparticle Modified Electrode

A biocompatible nanocomposite film was fabricated for hemoglobin (Hb) molecules immobilization. This film consists of multiwalled carbon nanotubes (MWNTs), 1‐pyrenebutanoic acid, succinimidyl ester (PASE), hemoglobin (Hb) and Au nanoparticles (AuNPs). Herein, PASE molecules physically adsorbed onto MWNTs, and its groups then covalently bond with Hb. AuNPs were then linked with Hb/PASE/MWNTs via electrostatic adsorption force. UV‐visible adsorption spectra, Fourier transform infrared spectra, scanning electron microscope and electrochemical impedance spectroscopy have characterized the film. Cyclic voltammetry (CV) scans showed that in the film Hb has well‐defined redox reaction, with the formal potential (E°) at about ?0.27 V (vs. Ag/AgCl). Herein, differential pulse voltammetry (DPV) was employed to electrochemically detect the Hb in the film with a detection limit of 9.3×10^?8 M. The proposed method was also succeeded for Hb detection in clinical blood samples. Furthermore, the Hb in the film showed good electrocatalytic activities to the reduction of H₂O₂, TCA, NaNO₂ and O₂.     

Hole‐Boosted Cu(Cr,M)O2 Nanocrystals for All‐Inorganic CsPbBr3 Perovskite Solar Cells

The all‐inorganic CsPbBr₃ perovskite solar cell (PSC) is a promising solution to balance the high efficiency and poor stability of state‐of‐the‐art organic–inorganic PSCs. Setting inorganic hole‐transporting layers at the perovskite/electrode interface decreases charge carrier recombination without sacrificing superiority in air. Now, M‐substituted, p‐type inorganic Cu(Cr,M)O₂ (M=Ba²⁺, Ca²⁺, or Ni²⁺) nanocrystals with enhanced hole‐transporting characteristics by increasing interstitial oxygen effectively extract holes from perovskite. The all‐inorganic CsPbBr₃ PSC with a device structure of FTO/c‐TiO₂/m‐TiO₂/CsPbBr₃/Cu(Cr,M)O₂/carbon achieves an efficiency up to 10.18 % and it increases to 10.79 % by doping Sm³⁺ ions into perovskite halide, which is much higher than 7.39 % for the hole‐free device. The unencapsulated Cu(Cr,Ba)O₂‐based PSC presents a remarkable stability in air in either 80 % humidity over 60 days or 80 °C conditions over 40 days or light illumination for 7 days.     

Triaqua(μ‐7‐iodo‐8‐oxidoquinoline‐5‐sulfonato‐κ2N,O8)dioxidouranium(VI) dihydrate

In the title compound, [U(C₉H₄INO₄S)O₂(H₂O)₃]·2H₂O, the asymmetric unit contains a UO₂²⁺ ion coordinated by the N and O atoms of a 7‐iodo‐8‐oxidoquinoline‐5‐sulfonate dianion (ferron anion) and three coordinated water molecules, and two uncoordinated water molecules. The UO₂²⁺ ion exhibits a seven‐coordinate pentagonal bipyramidal geometry. The usual sulfonate oxygen coordination is absent but the sulfonate O atoms, along with the coordinated and lattice water molecules, play a vital role in assembling the three‐dimensional structure via an extensive network of intermolecular O—H...O hydrogen bonds and π–π stacking interactions.     

Adsorptive features of polyacrylic acid hydrogel for UO2 2+

Polyacrylic acid hydrogel was synthesized by Free Radical polymerization and characterized by means of FTIR. The FTIR results show that the carboxylic groups in the complexes coordinated to the metal ions in the form of two dentate. The effects of contact time, solid/liquid ratio, pH value, and initial concentration on the adsorption of UO₂ ²⁺ ions onto polyacrylic acid were investigated. The adsorption of UO₂ ²⁺ ions was highly dependent on the initial pH of metal ions solution and initial metal ions concentration. The adsorption kinetic data indicated that the chemical adsorption was the swiftness processes, the adsorption equilibrium could be achieved within 15 min. And there are very good correlation coefficients of linearized equations for Freundlich model, which indicated that the sorption isotherm of the hydrogel for UO₂ ²⁺ can be fitted to the Freundlich model. It was found that the maximum adsorption quantity of UO₂ ²⁺ was 1,179 mg/g. After five times of repeated tests for the hydrogel it still remained its excellent adsorption.     

Magnetic porous carbon derived from a Zn/Co bimetallic metal–organic framework as an adsorbent for the extraction of chlorophenols from water and honey tea samples

A novel magnetic porous carbon derived from a bimetallic metal–organic framework, Zn/Co‐MPC, was prepared by introducing cobalt into ZIF‐8. Magnetic porous carbon that possesses magnetic properties and a large specific surface area was firstly fabricated by the direct carbonization of Zn/Co‐ZIF‐8. The prepared magnetic porous carbon material was characterized by scanning electron microscopy, transmission electron microscopy, powder X‐ray diffraction, N₂ adsorption, and vibrating sample magnetometry. The prepared magnetic porous carbon was used as a magnetic solid‐phase extraction adsorbent for the enrichment of chlorophenols from water and honey tea samples before high‐performance liquid chromatography analysis. Several experimental parameters that could influence the extraction efficiency were investigated and optimized. Under the optimum conditions, good linearities (r > 0.9957) for all calibration curves were obtained with low limits of detection, which are in the range of 0.1–0.2 ng mL^?1 for all the analytes. The results showed that the prepared magnetic porous carbon had an excellent adsorption capability toward the target analytes.     

Perylene diimide‐modified magnetic γ‐Fe2O3/CeO2 nanoparticles as peroxidase mimics for highly sensitive colorimetric detection of Vitamin C

Perylene diimide‐modified magnetic γ‐Fe₂O₃/CeO₂ nanoparticles (γ‐Fe₂O₃/CeO₂‐PDI) were prepared and exhibited excellent peroxidase‐like activity. The samples were characterized by HR‐TEM, XRD, Raman, N₂ adsorption, magnetic strength and XPS. The obtained γ‐Fe₂O₃/CeO₂‐PDI had size of 10~20 nm with high specific surface area of 77 m²/g, and could be easily separated from the aqueous solution by using a magnet, which are in favor of its practical application. Due to the decoration of PDI, the γ‐Fe₂O₃/CeO₂‐PDI possessed more surface defects (Ce³⁺) and active oxygen species than that of γ‐Fe₂O₃/CeO₂, resulting in the outstanding catalytic performance. And the composite catalyst also showed highly sensitive and selectivity toward VC with a limit of detection of 0.45 μM. Based on the fluorescent results, a possible hydroxyl radical (?OH) catalytic mechanism was proposed. It is believed that the as‐prepared γ‐Fe₂O₃/CeO₂‐PDI nanoparticles are promising biosensors applied for biomedical and food analysis.     

Novel bifunctional lanthanide‐centered nanophosphors for latent fingerprint detection and anti‐counterfeiting applications

Production of hybrid organic/inorganic complexes such as lanthanide phosphors in the nanodomain for human fingerprint visualization and anti‐counterfeiting ink under biocompatible UVA and blue light has not yet been studied that thoroughly. This paper presents the preparation of novel, bifunctional, green and red nanophosphors based on Eu³⁺ and Tb³⁺ complexes with quinolinone ligand (H₂L). They have been prepared and characterized for latent fingerprint detection and anti‐counterfeiting ink applications. The analytical data confirm that the ligand acts in a monoanionic bidentate manner through OO donor sites, forming mononuclear complexes, formulated as [Ln(HL)₃(C₂H₅OH)₃] (Ln = Eu³⁺ or Tb³⁺; L = 1‐ethyl‐4‐hydroxy‐3‐(nitroacetyl)quinolin‐2‐(1H)‐one). The Eu³⁺ and Tb³⁺ complexes have nanospherical morphologies with average particle sizes of 17 and 5 nm, respectively. Pure red and green photoluminescence with long lifetime values has been obtained from the Eu³⁺ and Tb³⁺ complexes, respectively, under non‐harmful UVA and blue illumination. Latent fingerprint details, including their characteristic three levels, have been clearly identified from various forensic (non‐porous, semi‐porous, highly fluorescent porous) substrates using red (Eu³⁺) and green (Tb³⁺) nanophosphors. The green nanophosphor powder has a greater capability for visualizing latent fingerprints from highly fluorescent porous surfaces as compared to the red one. Both nanophosphor complexes have been used to develop luminescent ink for anti‐counterfeiting applications.     

Photoinduced Multiple Effects to Enhance Uranium Extraction from Natural Seawater by Black Phosphorus Nanosheets

Based on the photoinduced photothermal, photoelectric, and photocatalytic effects of black phosphorus (BP) nanosheets, a BP‐PAO fiber with enhanced uranium extraction capacity and high antibiofouling activity is fabricated by compositing BP nanosheets into polyacrylamidoxime (PAO). The photothermal effect increases the coordination interaction between UO₂²⁺ and the functional amidoxime group, and the photoelectric effect produces the surface positive electric field that exhibits electrostatic attraction to the negative [UO₂(CO₃)₃]^4?, which all increase the capacity for uranium adsorption. The photocatalytic effect endows the adsorbent with high antibiofouling activity by producing biotoxic reactive oxygen species. Owing to these three photoinduced effects, the photoinduced BP‐PAO fiber shows a high uranium adsorption capacity of 11.76 mg g^?1, which is 1.50 times of the PAO fiber, in bacteria‐containing natural seawater.     

Redox‐Active Two‐Dimensional Covalent Organic Frameworks (COFs) for Selective Reductive Separation of Valence‐Variable,Redox‐Sensitive and Long‐Lived Radionuclides

We report the first example of 2D covalent organic framework nanosheets (Redox‐COF1) for the selective reduction and in situ loading of valence‐variable, redox‐sensitive and long‐lived radionuclides (abbreviated as VRL nuclides). Compared with sorbents based on chemical adsorption and physical adsorption, the redox adsorption mechanism of Redox‐COF1 can effectively reduce the impact of functional group protonation under the usual high‐acidity conditions in chemisorption, and raise the adsorption efficiency from the monotonous capture by pores in physisorption. The adsorption selectivity for UO₂²⁺ reaches up to unprecedented ca. 97 % at pH 3, more than for any analogous adsorbing material.     

Core–Shell Hollow Microspheres of Magnetic Iron Oxide@Amorphous Calcium Phosphate: Synthesis Using Adenosine 5′‐Triphosphate and Application in pH‐Responsive Drug Delivery

Drug nanocarriers with magnetic targeting and pH‐responsive drug‐release behavior are promising for applications in controlled drug delivery. Magnetic iron oxides show excellent magnetism, but their application in drug delivery is limited by low drug‐loading capacity and poor control over drug release. Herein, core–shell hollow microspheres of magnetic iron oxide@amorphous calcium phosphate (MIO@ACP) were prepared and investigated as magnetic, pH‐responsive drug nanocarriers. Hollow microspheres of magnetic iron oxide (HMIOs) were prepared by etching solid MIO microspheres in hydrochloric acid/ethanol solution. After loading a drug into the HMIOs, the drug‐loaded HMIOs were coated with a protective layer of ACP by using adenosine 5′‐triphosphate (ATP) disodium salt (Na₂ATP) as stabilizer, and drug‐loaded core–shell hollow microspheres of MIO@ACP (HMIOs/drug/ACP) were obtained. The as‐prepared HMIOs/drug/ACP drug‐delivery system exhibits superparamagnetism and pH‐responsive drug‐release behavior. In a medium with pH 7.4, drug release was slow, but it was significantly accelerated at pH 4.5 due to dissolution of the ACP shell. Docetaxel‐loaded core–shell hollow microspheres of MIO@ACP exhibited high anticancer activity.