Composite Microspheres Research Articles

Selective adsorption and identification of penicillin G sodium in milk by molecularly imprinted polymer doped carbon dot.

A carbon dot (CD) was prepared by o-phenylenediamine and water, which showed bright yellow fluorescence under ultraviolet light irradiation (λ = 580nm), and verified good fluorescence quenching effect on penicillin G sodium (Png-Na). Using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and Png-Na as a template, a kind of composite microsphere combining CD and molecularly imprinted polymer (MIP) was synthesized by surface-initiated atomic transfer radical polymerization (SI-ATRP). For reasons ofcomparison, we also prepared MIP without CD and non-imprinted polymers (NIPs). Through static and dynamic adsorption experiments, the maximum adsorption capacity was 47.05mgg-1 and the equilibrium time was 30min. High-performance liquid chromatography (HPLC) was utilized to determine the content of Png-Na in the spiked milk samples. A sensitive, rapid, and simple method for determination of Png-Na in food samples was developed. The utilized approach enabled the quantification of Png-Na within theconcentration range 20-1000μg L-1 (with a limit of detection of 5μg L-1). The recoveries achieved were in the range 93.3-98.2%, with a relative standard deviation of 1.2-4.2%. The results demonstrated that CD@MIP possessed the capability of specific adsorption and fluorescence detection of Png-Na, enabling simultaneous detection and enrichment of Png-Na in real samples.

Preparation and characterization of silver-carbon composite semitransparent hollow microspheres for surface-enhanced Raman scattering

In this work, silver-carbon composite semitransparent hollow spheres (Ag/HCSs) have been successfully synthesized via hydrothermal carbonization (HTC) with trioctylamine (TOA) as a stabilizer and soft template. Furthermore, silver-carbon composites with core-shell structure (Ag@CSs) and carbon films loaded with silver nanoparticles composites with lamellar structure (Ag/CFs) were prepared by adjusting the amount of TOA. The Ag/HCSs were composed of a matrix of ultrathin translucent hydrothermal hollow carbon microspheres with Ag nanoclusters embedded, and numbers of Ag@CSs inside and outside of the hollow carbon microspheres. We further investigated the growth mechanism and morphology evolution, on the basis of the properties of Ag and HCSs, explored the application of the Ag/HCSs for surface-enhanced Raman scattering (SERS). SERS activity was investigated using Rhodamine 6 G (R6G) and crystal violet (CV) as the SERS probe molecules. Ag/HCSs exhibit the best SERS performance among three products. The semitranslucent carbon shell, localized surface plasmon resonances of AgNPs and the effect of charge transfer arising from oxygen-containing moieties make the Ag/HCSs to exhibit good SERS performance, which may give a little inspiration to prepare novel SERS substrates.

Biomimetic fabrication of sr-silk fibroin co-assembly hydroxyapatite based microspheres with angiogenic and osteogenic properties for bone tissue engineering

Bone defects caused by trauma, tumor resection, or developmental abnormalities are important issues in clinical practice. The vigorous development of tissue engineering technology provides new ideas and directions for regenerating bone defects. Hydroxyapatite (HAp), a bioactive ceramic, is extensively used in bone tissue engineering because of its excellent osteoinductive performance. However, its application is challenged by its single function and conventional environment-unfriendly synthesis methods. In this study, we successfully "green" synthesized sr-silk fibroin co-assembly hydroxyapatite nanoparticles (Sr-SF-HA) using silk fibroin (SF) as a biomineralized template, thus enabling it to have angiogenic activity and achieving the combination of organic and inorganic substances. Then, the rough composite microspheres loaded with Sr-SF-HA (CS/Sr-SF-HA) through electrostatic spraying technology and freeze-drying method were prepared. The CCK-8 test and live/dead cell staining showed excellent biocompatibility of CS/Sr-SF-HA. Alkaline phosphatase (ALP) staining, alizarin red staining (ARS), immunofluorescence, western blotting, and qRT-PCR test showed that CS/Sr-SF-HA activated the expression of related genes and proteins, thus inducing the osteogenic differentiation of rBMSCs. Moreover, tube formation experiments, scratch experiments, immunofluorescence, and qRT-PCR detection indicated that CS/Sr-SF-HA have good angiogenic activity. Furthermore, in vivo studies showed that the CS/Sr-SF-HA possesses excellent biocompatibility, vascular activity, as well as ectopic osteogenic ability in the subcutaneous pocket of rats. This study indicates that the construction of CS/Sr-SF-HA with angiogenic and osteogenic properties has great potential for bone tissue engineering.

Preparation of magnetic DTPA-modified chitosan composite microspheres for enhanced adsorption of Pb(II) from aqueous solution

In this study, magnetic DTPA-modified chitosan composite microspheres (MDCM) were prepared by reverse emulsion-double crosslinking method (carbodiimide followed by glutaraldehyde) for removal of Pb(II) from aqueous solution. The obtained magnetic adsorbents were characterized by FTIR, SEM, XRD, VSM, BET, and 13C NMR. The effects of the pH, contact time, initial concentration, and competitive metal cations (Na(I), Ca(II), or Mg(II)) on Pb(II) adsorption were investigated. The results revealed that MDCM exhibited high removal performance over a wide pH range and in the presence of competitive metal cations. The maximum adsorption capacity of MDCM for Pb(II) is 214.63 mg g−1 at pH 3, which is higher than most recently reported magnetic adsorbents. Adsorption kinetics and isotherms can be described by the pseudo-second-order model and Langmuir model, respectively. In addition, MDCM is easy to regenerate and can be reused five cycles with high adsorption capacity. Finally, the adsorption mechanism was further revealed by FTIR and XPS analysis. Overall, MDCM has practical application potential in removing Pb(II) from contaminated wastewater due to its high adsorption efficiency, good reusability, and convenient magnetic separation.

Efficient NiFeCr0.1/NF by incorporating chromium to boost OER catalysis

This study developed ternary NiFeCr hydroxide microsphere composites for efficient oxygen evolution reaction (OER) in alkaline water. Compared to binary NiFe composites, the ternary composites exhibited superior electrocatalytic activity. In a 1 M KOH solution, the ternary composite demonstrated a low initial potential of 1.46 V (RHE), and the overpotential is only 268 mV @ 100 mA cm−2. Charge rearrangement due to chromium oxidation helped maintain iron's low oxidation state, preserving OER activity. The redistribution of chromium particles stabilized iron and prevented its dissolution in an alkaline solution. Consequently, the optimized NiFeCr catalyst exhibits excellent stability, with a stability of 200 h at 100 mA cm−2. This study offers a novel approach to designing efficient and stable catalysts for water decomposition.

Electrospray fabrication of CL-20 composite microspheres for high-energy EFIs: Microstructure modulation and performance optimization

The utilization of high-energy explosives in Explosive Foil Initiators (EFIs) holds paramount significance. In this study, CL-20 composite microspheres were successfully prepared by electrostatic spraying technology, demonstrating narrow size distribution and high sphericity at 5% binder content. The strategy of introducing NC in GAP and F2602 effectively improved the porosity, specific surface area and apparent activation energy of CL-20 microspheres, where the increased specific surface area contributed to the narrow pulse sensibility of CL-20 microspheres. Compared to raw CL-20, these microspheres exhibited markedly improved safety properties. Comparative analysis with the HNS-IV revealed that CL-20 microspheres, with GAP/NC binder, demonstrated the minimum firing voltage of 1.10 kV and the narrow pulse initiation energy of 0.121 J, which was close to that of HNS-IV (1.08 kV and 0.117 J). However, CL-20 microspheres exhibited significantly enhanced detonation performance and output energy. The application of CL-20 microspheres in EFIs promoted the EFIs' miniaturization development.

Hemocompatible polyethylenimine-grafted poly (glycidyl methacrylate) based microspheres for effective endotoxin removal

Endotoxin (also known as lipopolysaccharide, LPS), the major component in the outer cell wall of Gram-negative bacteria, is considered to be a main cause of sepsis. To reduce the mortality of sepsis, adsorbents with positively charged surfaces like polyethylenimine (PEI) are commonly employed to adsorb endotoxins; however, there are hidden dangers in binding stability and hemocompatibility of PEI-grafted materials. Herein, poly (glycidyl methacrylate) microspheres prepared by electro-spraying are chosen as the substrate, the surface epoxy groups are utilized to chemically immobilize PEI molecules. Then, heparin coatings are introduced through electrostatic interaction to obtain composite microspheres as hemoperfusion adsorbent. As a result, the hemocompatibility of the microspheres is significantly improved after the introduction of the heparin coatings. Compared to the microspheres only grafting PEI, the hemolysis ratio has a huge decrease from 4.6% to 1.0%. The adsorption process of the composite microspheres is more consistent with Sips isotherm model with a theoretical maximum endotoxin adsorption capacity of 2659.1 EU/g in normal saline solution. And the microspheres exhibit high endotoxin clearance ratio of 81.3% in static plasma (C0 = 12.6 EU/mL, exceeding critical illness level). In vitro dynamic adsorption experiments also indicate that the microspheres remove 86.6% of endotoxin in septic plasma (C0 = 7.2 EU/mL, exceeding critical illness level) within 1 h. We hope that the composite microspheres could have good application potential as an efficiency endotoxin adsorbent in sepsis treatment.

Research Progress on the Preparation of Inorganic/Natural Materials Composite Microspheres

Microspheres are a new type of drug carrier with great potential for development and application. Natural polymers have good biocompatibility, biodegradability, and are easily dispersed in living organisms, making them suitable for preparing microspheres. Inorganic materials (mainly inorganic minerals) have excellent mechanical properties and are inexpensive and easy to obtain. Through the coupling and hybridization of natural polymers and inorganic materials, they can complement each other's advantages and synergistically enhance efficiency, resulting in many excellent physical and chemical properties. Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking, solution mixing, in-situ synthesis, extrusion, etc. The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects, is safe and non-toxic, and the cost of carrier materials is relatively low, which has certain significance for the development of new drug carriers. This article reviews the recent research on the preparation, drug loading and release properties of inorganic material/natural polymer composite microspheres, analyzes the advantages and disadvantages of commonly used preparation methods, and looks forward to the development direction of composite microspheres.

Rational design of agarose/dextran composite microspheres with tunable core–shell microstructures for chromatographic application

A new type of core-shell microsphere was prepared by a pre-crosslinking method, consisting of cross-linked agarose microspheres as the core and agarose-dextran as the shell. After optimizing the preparation process, the microspheres with a uniform particle size were obtained and characterized using cryo-scanning electron microscopy to determine their surface and cross-sectional morphology. Results from flow rate-pressure and chromatographic performance tests showed that the core-shell agarose microspheres were supported by the core microspheres and composed of composite polysaccharides, forming an interpenetrating polymer network structure as a hard shell. The core-shell agarose microspheres showed a 300.5 % increase in linear flow rate compared to composite polysaccharide microspheres prepared from shell materials and a 141.5 % increase compared to 6 % agarose microspheres. Additionally, the large pore structure of the shell combined with the fine pore structure of the core improved the material separation efficiency in the range of 0.1–2000 kDa. These findings suggest that core-shell natural polysaccharide microspheres have great potential as a separation chromatographic medium.

Optimization of process variables and characterization of mechanically agitated ceramic‐microsphere reinforced aluminium composite

AbstractThis study aims to investigate the effect of stir‐casting process parameters, including stirring speed, stirring time, and weight % of the ceramic microsphere, on the fabrication of an aluminium 6061‐ceramic microsphere composite. Experiments are conducted using a full‐factorial design approach to determine the effect of variables on mechanical properties. A field effect scanning electron microscope is used to analyze the fracture surfaces of the test specimen. Further, the results are subjected to the Anderson‐darling normality test to validate the accuracy of the model, and finally, an analysis of variance is performed to identify the most significant parameters that affect the mechanical properties. The results confirm the validity of the designed experimental model for enhancing the mechanical properties of the aluminium 6061‐ceramic microsphere composite. The optimum mechanical properties are attained for a stirring speed of 600 min−1, stirring time of 15 min, and 5 weight % of reinforcement. Furthermore, the weight percentage of the ceramic microsphere increase, the ductility of the composite decreases while its strength and hardness increase. Finally, the analysis of variance shows that all parameters significantly impact the mechanical properties of the designed composite.

Cheap and efficient strategy for photocatalytic degradation of ionic liquids by La/Ce-codoped TiO2@PAM composites.

Ionic liquids are regarded as green solvents mainly due to their non-volatile and easy regeneration and recycling properties. However, ionic liquids have negative effects on the environment and human health, especially alkyl imidazole ionic liquids are more toxic than traditional organic solutions. Studies on the toxicology, ecotoxicology, and degradation of ionic liquids are rarely found in the literature. Here, we prepared the cheap La and Ce-codoped TiO2@PAM (polyacrylamide) composite microspheres with a simple procedure for the first time to degrade three kinds of imidazole ionic liquids with high efficiency. The experimental results show that the composite La (0.25%) and Ce (0.15%)-codoped TiO2@PAM composite microspheres with calcination temperature of 450 °C had a high photocatalytic activity for 1-butyl-3-methyl imidazolium hexafluorophosphate, 1-hexyl-3-methyl imidazolium hexafluorophosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate with the concentration of 10 mg/L. The photocatalysis degradation extent of the three ionic liquids is 97.4, 91.2, and 88.5% at 90 min. This work opened a new route for the simple preparation of cheap composite microspheres in the photocatalytic degradation of ionic liquids with a high efficiency.

Nano-ZnO enhanced amidoxime-functionalized sodium alginate composite hydrogel microspheres for uranium capture from wastewater

Effective removal of uranium from wastewater is of vital significance for the human health and environmental protection. In this paper, by adopting the use of co-mingling and covalent cross-linking methods, nano-ZnO enhanced the amidoxime-functional sodium alginate composite hydrogel (SA/CMC-ZnONPS-AO1) was prepared. The mechanical stability of SA/CMC-ZnONPS-AO1 was improved with the assistance of ZnO. The introduction of amidoxime group effectively improved the selectivity of uranyl ions (KdU = 10016 mL/g). The fitted maximum adsorption capacity of SA/CMC-ZnONPS-AO1 for U(VI) was 641.7 mg/g at 298 K and pH = 4. This is higher than most of sodium alginate-based adsorbents which were currently used for uranium removal from wastewater. Furthermore, in the dynamic adsorption column experiment at the scale of the laboratory, the adsorption equilibrium (163 mg/g) was acquired after 3 days in a low-concentration uranium solution (50 mg/L). Finally, the possible adsorption mechanism was discussed. This study not only provides a new method for the preparation of adsorption agents, but also provides theoretical support for the actual application of adsorbents in the uranium-containing wastewater.

Adsorption of Levofloxacin onto Graphene Oxide/Chitosan Composite Aerogel Microspheres.

The removal of pharmaceutical residues from water resources using bio-based materials is very important for human safety and health. Bio-based graphene oxide/chitosan (GO/CS) aerogel microspheres were fabricated with emulsification and cross-linking, followed by freeze drying, and were used for the adsorption of levofloxacin (LOF). The obtained GO/CS aerogel microspheres were characterized with scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and thermogravimetry (TG). The effects of GO content, pH value, and temperature on their adsorption capacity were investigated. With the incorporation of 40 wt% GO, the adsorption capacity increased from 9.9 to 45.6 mg/g, and the highest adsorption capacity, 51.5 mg/g, was obtained at pH = 8 and T = 25 °C. In addition, to obtain deeper insight into the adsorption process, the thermodynamics and kinetics of the process were also investigated with four different models of LOF adsorption. The thermodynamic modeling results revealed that LOF adsorption is exothermic, and the kinetic investigation demonstrated that LOF adsorption is generally consistent with a pseudo-first-order rate law.

A novel icariin‐encapsulated PLGA/nBM composite biomimetic microspheres for bone repair

AbstractDeer bone in traditional Chinese medicine is valued for its unique biomimetic bone matrix components. Icariin (Ica), which is claimed by Chinese medicine as a bone‐repairing agent, is also widely accepted. In this report, a novel Ica‐encapsulated PLGA/nano deer bone meal (Ica@PLGA/nBM) biomimetic microsphere was fabricated. The Ica could be released from microspheres in a controlled manner. In vitro results showed that the microsphere had good biocompatibility due to the addition of nBM and the MC3T3‐E1 cells could adhere to and grow well on the microspheres. Moreover, Ica and nBM in microspheres could synergically promote the ALP activity of MC3T3‐E1 cells significantly (p < 0.05), which indicated the acceleration of osteogenic differentiation. The RT‐PCR results showed that the expression levels of bone matrix proteins (Col1 & OPN) were enhanced by the composite (p < 0.05). In addition, Ica and nBM in microspheres also obviously promoted the expression of RUNX2 and BMP‐2, respectively (p < 0.05). The in vivo results demonstrated the effective promotion of Ica@PLGA/nBM on complete bony connection to cover the defect site and the bone defect repair. And the Ica(M)@PLGA/nBM microspheres provided the best repair results. All the results confirmed that the Ica@PLGA/nBM composite biomimetic microsphere has the potential for clinical application.

Preparation and Performance Study of a Novel Antibacterial Hemostatic Chitosan Sponge

To create a novel chitosan antibacterial hemostatic sponge (NCAHS) and to evaluate its material and biological properties. Chitosan, a polysaccharide, was used as the sponge substrate and different proportions of sodium tripolyphosphate (STPP), glycerol, and phenol sulfonyl ethylamine were added to prepare the sponges through the freeze-drying method. The whole-blood coagulation index (BCI) was used as the screening criterion to determine the optimal concentrations of chitosan and the other additives and the hemostatic sponges were prepared accordingly. Zein/calcium carbonate (Zein/CaCO3) composite microspheres loaded with ciprofloxacin hydrochloride were prepared and added to the hemostatic sponges to obtain NCAHS. Scanning electron microscope was used to observe the microscopic morphology and porosity of the NCAHS. The water absorption rate, in vitro antibacterial susceptibility rate against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), in vitro coagulation performance, and hemocompatibility of NCAHS were examined. The coagulation performance of NCAHS was evaluated by using rabbit liver injury and rabbit auricular artery hemorrhageear models and commercial hemostatic sponge (CHS) was used as a control. The in vivo biocompatibility, including such aspects as cytotoxicity, skin irritation in animals, and acute in vivo toxicity, of the NCAHS extracts was examined by using as a reference the national standards for biological evaluation of medical devices. The NCAHS prepared with 1.5% chitosan (W/V), 0.01% STPP (W/V), 0% glycerol (V/V), 0.15% phenol-sulfonyl-ethylamine (V/V), Zein and CaCO3 at the mixing ratio of 5∶1 (W/W), Zein at the final mass concentration of 2.5 g/L, and ethanol at the final concentration of 17.5% (V/V) were fine and homogeneous, possessing a honeycomb-like porous structure with a pore size of about 200 μm. The NCAHS thus prepared had the lowest BCI value. The water absorption ([2362.16±201.15] % vs. [1102.56±91.79]%) and in vitro coagulation performance (31.338% vs. 1.591%) of NCAHS were significantly better than those of CHS (P<0.01). Tests with the in vivo auricular artery hemorrhage model ([36.00±13.42] s vs. [80.00±17.32] s) and rabbit liver bleeding model ([30.00±0] s vs. [70.00±17.32] s) showed that the hemostasis time of NCAHS was significantly shorter than that of CHS (P<0.01). NCAHS had significant inhibitory ability against S. aureus and E. coli. In addition, NCAHS showed good in vitro and in vivo biocompatibility. NCAHS is a composite sponge that shows excellent antimicrobial properties, hemostatic effect, and biocompatibility. Therefore, its extensive application in clinical settings is warranted.

Preparation and microwave absorption properties of flexible composites containing Ag decorated polystyrene powders

Polystyrene (PS) microspheres have the advantages of good stability, corrosion resistance and low density, which have a broad application prospect. In this paper, PS composite microspheres with 20% silver plating content were prepared by chemical plating method and incorporated into polydimethylsiloxane (PDMS) flexible matrix to prepare Ag@PS/PDMS flexible wave-absorbing materials. The electromagnetic parameters were adjusted to optimize the dielectric and wave-absorbing properties by varying the additional amount of Ag@PS composite microspheres in Ag@PS/PDMS composites. The X-ray diffraction (XRD) results proved the successful preparation of Ag@PS composite microspheres. The SEM and EDS images indicated that the Ag particles were attached to the external surface of PS. The presence of Ag particles in the Ag@PS composite microspheres enhances their electrical conductivity and enables the formation of a conductive network. This, in turn, improves the composites’ dielectric constant. The optimal wave-absorbing capability of the composites was achieved when the Ag@PS composite microspheres were added at a weight percentage of 50%. When the sample attains a thickness of 1.8[Formula: see text]mm, a reflection loss of at least −39.8[Formula: see text]dB is attained at 10.4[Formula: see text]GHz, along with a bandwidth of 1.6[Formula: see text]GHz (9.1–10.7[Formula: see text]GHz) for the effective absorption bandwidth (EAB). The pressure-sensitive properties of the pliable composites were investigated as well. The optimal pressure-sensitive performance of Ag@PS/PDMS composites was achieved with a 60[Formula: see text]wt.% addition of Ag@PS composite microspheres. The resistance undergoes significant changes when subjected to pressure with a sensitivity of 9.7. The results indicate that the flexible composites’ wave-absorption and pressure-sensitivity properties can be modulated by adjusting the amount of Ag@PS composite microspheres added.

A novel alginate-embedded magnetic biochar-anoxygenic photosynthetic bacteria composite microspheres for multipollutant removal: Mechanisms of photo-bioelectrochemical enhancement and excellent reusability performance

Existing wastewater treatment technologies face the key challenge of simultaneously removing emerging contaminants and nutrients from wastewater efficiently, with a simplified technological process and minimized operational costs. In this study, a novel alginate-embedded magnetic biochar-anoxygenic photosynthetic bacteria composite microspheres (CA-MBC-PSB microspheres) was prepared for efficient, cost-effective and one-step removal of antibiotics and NH4+-N from wastewater. Our results demonstrated that the CA-MBC-PSB microspheres removed 97.23% of sulfadiazine (SDZ) within 7 h and 91% of NH4+-N within 12 h, which were 21.23% and 38% higher than those achieved by pure calcium alginate-Rhodopseudomonas palustris microspheres (53% and 45.7%), respectively. The enhanced SDZ and NH4+-N removal were attributed to the enhanced photoheterotrophic metabolism and excretion of extracellular photosensitive active substances from R. Palustris through the photo-bioelectrochemical interaction between R. Palustris and magnetic biochar. The long-term pollutants removal performance of the CA-MBC-PSB microspheres was not deteriorated but continuously improved with increasing ruse cycles with a simultaneous removal efficiency of 99% for SDZ and 92% for NH4+-N after three cycles. The excellent stability and reusability were due to the fact that calcium alginate acts as an encapsulating agent preventing the loss and contamination of R. palustris biomass. The CA-MBC-PSB microspheres also exhibited excellent performance for simultaneous removal of SDZ (89% in 7 h) and NH4+-N (90.7% in 12 h) from the secondary effluent of wastewater treatment plant, indicating the stable and efficient performance of CA-MBC-PSB microspheres in practical wastewater treatment.

Preparation and Properties of GO/ZnO/nHAp Composite Microsphere Bone Regeneration Material.

The purpose of this study is to explore the possibility of using graphene-zinc oxide-hydroxyapatite (GO/ZnO/nHAp) composite microspheres as bone regeneration materials by making use of the complementary advantages of nanocomposites, so as to provide reference for the clinical application of preventing and solving bacterial infection after implantation of synthetic materials. Firstly, GO/ZnO composites and hydroxyapatite nanoparticles were synthesized using the hydrothermal method, and then GO/ZnO/nHAp composite microspheres were prepared via high-temperature sintering. The graphene-zinc oxide-calcium phosphate composite microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), energy dispersion spectroscopy (EDS), water contact angle measurement, degradation and pH determination, and differential thermal analysis (DiamondTG/DTA). The biocompatibility, osteogenic activity, and antibacterial activity of GO/ZnO/nHAp composite microspheres were further studied. The results of the cell experiment and antibacterial experiment showed that 0.5% and 1% GO-ZnO-nHAp composite microspheres not only had good biocompatibility and osteogenic ability but also inhibited Escherichia coli and Staphylococcus aureus by more than 45% and 70%. Therefore, GO/ZnO/nHAp composite microspheres have good physical and chemical properties and show good osteogenic induction and antibacterial activity, and this material has the possibility of being used as a bone regeneration material.

N, O-Doped Walnut-Like Porous Carbon Composite Microspheres Loaded with Fe/Co Nanoparticles for Adjustable Electromagnetic Wave Absorption.

This study addresses the challenge of designing simple and environmentally friendly methods for the preparation of effective electromagnetic wave (EMW) absorbing materials with tailored microstructures and multi-component regulation. N, O doped walnut-like porous carbon composite microspheres loaded with FeCo nanoparticles (WPCM/Fe-Co) are synthesized through high-temperature carbonization combined with soap-free emulsion polymerization and hydrothermal methods, avoiding the use of toxic solvents and complex conditions. The incorporation of magnetic components enhances magnetic loss, complementing dielectric loss to optimize EMW attenuation. The unique walnut-like morphology further improves impedance matching. The proportions of Fe and Co components can be adjusted to regulate the material's reflection loss, thickness, and bandwidth, allowing for fine-tuning of absorption performance. At a low filling ratio (16.7%), the optimal WPCM/Fe-Co composites exhibit a minimum reflection loss (RLmin) of -48.34dB (10.33GHz, 3.0mm) and an overall effective absorbing bandwidth (EAB) covering the entire C bands, X bands, and Ku bands. This work introduces a novel approach to composition regulation and presents a green synthesis method for magnetic carbon composite absorbers with high-performance EMW absorption at low loading.

Ultrasensitive simultaneous determination of hydroquinone and catechol by Ni3ZnC0.7/Ni porous composites derived from Ni/Zn-MOF

Rational constructing metal–organic frameworks (MOFs) based composite materials with outstanding catalytic capability is vital to accomplish high-performance electrochemical sensors. In this paper, the precursor Ni/Zn-MOF was fabricated by a simple one-step solvothermal method, and then the Ni nanoparticle-supported porous microsphere composites (Ni3ZnC0.7/Ni) were obtained by pyrolysis in N2 atmosphere. The physicochemical characteristics of the as-prepared Ni3ZnC0.7/Ni were studied by XRD, SEM, EDS, TEM, FTIR and XPS, and their electrocatalytic activity were tested by Cyclic voltammetry (CV) and differential pulse voltammetry (DPV). On this basis, an electrochemical sensor strategy for the simultaneous determination of hydroquinone (HQ) and catechol (CC) with Ni3ZnC0.7/Ni modified glassy carbon electrode (GCE) was proposed. In addition, they were applied to the electrochemical simultaneous detection of HQ and CC for the first time. Compared with NiC and ZnC modified electrode, the Ni3ZnC0.7/Ni composites modified electrode can significantly enhance electrocatalytic activity and improve the selectivity and sensitivity of the detection of HQ and CC. The performance was due to increasing the active surface area of the modified electrode and the Ni atom has excellent electrocatalytic capability to dihydroxybenzene. The experimental results exhibits that the composite was used to achieve simultaneous detection of HQ and CC in single-component or two-component solutions with satisfactory result. It has a low limit of detections (LOD = 3σ/k) (HQ: 0.14 μM, CC: 0.21 μM) and a wide detection range (HQ: 0.3–100.0 μM, CC: 0.5–100.0 μM). Meanwhile, the constructed sensor has been successfully employed for determination of HQ and CC in Yellow River water and tap water, and obtains good recovery rate. This work develops a new approach for design and engineering of MOF materials for electrochemical sensors and environmental monitoring.