Nanocomposite Microspheres Research Articles

Synthesis, characterization, and adsorption study of Congo Red on melamine-formaldehyde nanocomposite microspheres

Synthesis, characterization, and adsorption study of Congo Red on melamine-formaldehyde nanocomposite microspheres

In Situ Synthesis of Exfoliated Ni(OH)2 Nanosheets and AgNPs-Embedded Functionalized Polyindole-Based Trinary Hybrid Microspheres: A Z-Scheme Photocatalyst for the Sunlight-Driven Degradation of Organic Pollutants with Enhanced Antibacterial Efficacy.

Advancing a facile one-pot synthetic approach for the fabrication of a hybrid heterojunction photocatalyst remains a significant challenge in research pursuits. Herein, a microsphere-like trinary hybrid nanocomposite has been synthesized (NH/PIn/MAA/Ag). It comprises exfoliated single- and a few-layered Ni(OH)2 (NH nanosheets), mercaptoacetate-functionalized polyindole (PIn/MAA), and Ag nanoparticles (AgNPs) through an in situ approach. The formation mechanism is based on the exfoliation of stacked Ni(OH)2 multilayers [i.e., Ni(OH)2 microflowers] and stabilization of NH nanosheets through host-guest formation of PIn/MAA, followed by the adsorption-reduction of Ag+ ions in a one-pot reaction at low temperature. Surface morphological analyses of hybrid nanocomposite microspheres have exhibited that highly dense Ni(OH)2 microflowers have been transformed into low-density layered forms (NH nanosheets) within the polymeric platform (PIn/MAA) with deposited AgNPs. An interfacial heterojunction has been developed between the components in the depletion region, leading to an improvement in photocatalytic efficiency through a synergistic effect over the components for charge separation and transfer through the heterojunction interface via solid-state mediator Ag-based Z-scheme charge transfer dynamics. The superior photocatalytic degradation of tetracycline (98.2%) by trinary hybrid microspheres can be attributed to the deteriorated recombination rate of electron-hole pairs with reduced charge transfer resistance of the heterojunction in the photocatalyst, as obvious from photoluminescence, electrochemical impedance spectroscopy, chronoamperometry, and time-resolved photoluminescence (TRPL) analyses. Moreover, the antibacterial properties of microspheres against Bacillus pumilus (Gram-positive) and Escherichia coli (Gram-negative) bacteria have validated their potential as promising materials for the overall purification of aquatic systems.

Compact homogeneous Si/SiC/C in-situ nanocomposite microspheres as anode materials for lithium-ion batteries

Compact homogeneous Si/SiC/C in-situ nanocomposite microspheres are synthesized by a procedure consisted of sol-gel, air calcination and magnesiothermic reduction processes. The components of Si, C, and SiC are all generated in situ and have the advantages of high dispersion and uniform distribution at the nanoscale level, which can maximize the conductivity and structural stability of nanocomposite microspheres when used as the anode materials for lithium-ion batteries. A series of samples with different compositions and morphologies are obtained by controlling the temperature in the air calcination step. Electrochemical tests reveal that the sample with the best comprehensive performance delivers an initial coulombic efficiency of 79.1 %, a reversible specific capacity of 1513 mAh g−1, and a capacity retention of 87.8 % after 200 cycles. The significantly enhanced electrochemical performance relative to the pure Si sample composed of irregular nanoparticles confirms that the method of synthesizing compact homogeneous materials through in-situ means is highly effective and promising for the fabrication of high-performance electrode materials.

Idebenone-Loaded Nanocomposite Microspheres for Nasal Administration-A Perspective in the Treatment of Alzheimer's Disease.

Alzheimer's disease results in neurodegeneration and is characterized by an accumulation of abnormal neuritic lesions and intracellular aggregates of hyperphosphorylated Tau proteins in the cerebrum. That leads to progressive decline in memory, thinking, and learning skills. Oxidative stress has been shown to play a significant role in the pathogenesis of Alzheimer's disease. Antioxidants are identified as part of therapeutic strategy to prevent or reduce the disease. Idebenone is a synthetic analogue of coenzyme Q10 with potent antioxidant properties, originally developed for the treatment of Alzheimer's disease and other cognitive disorders. After oral administration idebenone undergoes excessive first-pass metabolism and has a very low bioavailability of only about 1%. The use of an alternative route of administration such as the nasal and its incorporation into a novel carrier (nanocomposite microspheres) will eliminate the problems associated with reduced absorption, stability, and rapid biotransformation and will increase the opportunity for idebenone to realize its therapeutic potential in Alzheimer's disease. Idebenone-loaded nanocomposite microspheres were obtained by spray drying. The structures were characterized using laser diffraction, scanning electron microscopy, high-performance liquid chromatography, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. The ability of nanocomposite microspheres to bind human serum albumin was investigated by fluorescence spectroscopy. The mucoadhesive properties of the carrier were also determined. Bioadhesive nanocomposite microparticles with spherical shape, smooth surface, size of 7.37 ± 2.4 μm, and with high production yield, good drug entrapment efficiency, and loading values were obtained. Infrared spectra demonstrated no chemical interactions between idebenone and structure-forming polymers. The ability of particles to bind to human serum albumin depends on their drug loading. Nanocomposite microspheres were developed as the novel delivery system of idebenone for target nose-to-brain delivery. The obtained carrier may increase the therapeutic potential of idebenone by providing higher concentrations in brain tissue and reducing systemic exposure and side effects.

Carbon-coated ZnO Nanocomposite Microspheres as Anode Materials for Lithium-ion Batteries

Carbon-coated ZnO Nanocomposite Microspheres as Anode Materials for Lithium-ion Batteries

Remediation of Pb (II), Cd (II), and Zn (II) from aqueous solutions using porous (styrene-divinylbenzene)/Cu-Ni bimetallic nanocomposite microspheres: continuous fixed-bed column study.

Bimetallic nanoparticles (BNPs) have been used as a new line of defence against heavy metal contamination among several types of nanoparticles (NPs) due to their enhanced, synergistic activity. In this study, we investigated the adsorption behaviour of porous (styrene-divinylbenzene)/CuNi bimetallic nanocomposite (P(St-DVB)/CuNi BNC) in a continuous flow fixed-bed column and its ability to remove Pb (II), Cd (II), and Zn (II) ions from aqueous solutions. We examined how the initial metal concentration, flow rate, and bed height affected the adsorption characteristics. Experimental results confirmed that the adsorption capacity increased with increase in influent metal concentration and bed height and decreased with increase in flow rate. The breakthrough and the column kinetic parameters were successfully predicted with three mathematical models: Thomas, Yoon-Nelson, and Adams-Bohart models. Both Thomas and Yoon-Nelson models showed good agreement with the experimental results for all the operating conditions. Successful desorption of heavy metals from the P(St-DVB)/CuNi BNC was performed using 0.5 M NaOH solution, and it showed good reusability of the adsorbent during four adsorption-desorption cycles. The results show that P(St-DVB)/CuNi BNC are effective and low-cost adsorbents, and they can be used in real-time large-scale industrial water treatment processes for the removal of heavy metals.

Study on antibacterial activity and repair of peripheral nervous system injury by Zno nanocomposites

In this paper, three samples of ZnO/PPy, ZnO/CNTs and ZnO/PPy/CNTs nano- composites were studied in the aspects of antimicrobial properties, cell imaging and tumor targeting. Firstly, Escherichia coli strains were selected and controlled test method was used. Colony data showed that the inhibition rate of ZnO/PPy was 73.06%, the inhibition rate of ZnO /CNTs was 99.44%, and the inhibition rate of ZnO/PPy/CNTs composite was 99.99%. The results showed that the three kinds of composites had certain antibacterial effect. At the same time, in order to optimize the application of nano-sized zinc oxide (ZnOs), ZnOs nanocomposite microspheres were prepared by emulsification and dispersion method with polypyrrole and carbon nanotubes as microballoon walls, and the animal model of peripheral nervous system (PNS) injury was established. ZnOs nanocomposite microspheres and control samples were implanted into the injured peripheral nervous system (sciatic nerve was used as the site). The experimental results show that ZnOs nanocomposite microspheres can repair peripheral nervous system injury in animals.

A novel silica-reinforced P(AM/AMPS/SA/TM-SiO2) microspheres for selective adsorption of methylene blue from aqueous solution

The development of adsorption materials with large adsorption capacity, high selectivity and strong regeneration ability is of great significance for the treatment of dye wastewater. With the aim of obtaining a microsphere with stable structure, large adsorption capacity and rich negative charge for selective adsorption of methylene blue (MB) and other cationic dyes from aqueous solution, a novel silica-reinforced P(AM/AMPS/SA/TM-SiO2) microspheres were synthesized from acrylamide (AM), 2-acrylamido-1-methyl-1-propane sulfonic acid (AMPS), sodium alginate (SA) and trimethoxy(vinyl)silane modified silica (TM-SiO2) through microemulsion polymerization method. The structural properties of the microspheres were analyzed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and dynamic light scattering (DLS). The influences of TM-SiO2 content on particle size distribution, swelling property, and mechanical stability of the microspheres were thoroughly investigated. The results revealed that TM-SiO2 could effectively adjust the particle size distribution range, reduce the swelling degree, and improve the mechanical stability of the microspheres. The effects of temperature, contact time and initial concentration of MB on the adsorption capacity of the microspheres were systematically inquired. The adsorption capacity of P(AM/AMPS/SA/TM-SiO2) microspheres for MB was 362.52 mg/g at 25℃, while that of P(AM/AMPS/SA) microspheres was 307.17 mg/g. Furthermore, P (AM/AMPS/SA/TM-SiO2) nanocomposite microspheres still maintained a complete shape and high adsorption capacity after five adsorption–desorption cycles. The pseudo-second-order kinetic model and Langmuir model were adopted to describe the adsorption process of MB on the microspheres. Moreover, the intermolecular interaction between the microspheres and MB were explored by quantum chemical (QC) calculations. A possible adsorption mechanism was proposed.

Multifunctional inorganic/organic nanocomposite microspheres - reinventing eggs for bone repair applications

This study reports for first time the development of bone-regenerative nanocomposite microspheres re-engineered from chicken eggs. We deployed a novel hybrid crosslinking technique combining chemical and thermal crosslinking to produce highly cross-linked microspheres consisting of organic egg white matrix and bioactive inorganic egg shell nanofillers. The nanocomposite microspheres exhibit enhanced mechanical properties and prolonged degradation profile. Ca2+ released from the microspheres are found to accelerate the biomineralization process, facilitate the stem cell differentiation, and promote the osteogenesis process. In addition, antibiotic drug levofloxacin has been loaded onto the proposed microspheres and the dual function of the microspheres in bacterial infection control and bone regeneration has been successfully demonstrated in animal models. Results show that our nanocomposite microspheres can serve as a promising multifunctional platform for bone repair applications.

Synthesis of nanofibrous chitosan/Fe3O4/TiO2@TiO2 microspheres with enhanced biocompatibility and antibacterial property

AbstractMultifunctional materials have received considerable attention as they could integrate different functional components in one‐single platform. In this study, novel chitosan/Fe3O4/TiO2@TiO2 nanowire (NW) microspheres having extracellular matrix‐like fibrous surface and photothermal antibacterial property were synthesized through in situ hydrothermal growth of TiO2 NWs on chitosan/Fe3O4/TiO2 microspheres. It is found that the microspheres were spherical in morphology with a diameter of 100–300 µm and exhibited a hierarchical and nanofibrous feature. Their surface was mainly constructed by numerous TiO2 NWs with a diameter of 20– 30nm. In vitro biological evaluation indicates that the chitosan/Fe3O4/TiO2@TiO2 NW microspheres significantly enhanced attachment and proliferation of human umbilical vein endothelial cells compared with chitosan/Fe3O4/TiO2 nanocomposite microspheres due to the presence of nanofibrous surface. Moreover, the microspheres showed photothermal antibacterial property to inhibit the growth of bacteria due to the presence of Fe3O4 component.

Monodisperse Porous Silica/Polymer Nanocomposite Microspheres with Tunable Silica Loading, Morphology and Porosity

Hybrid organic/inorganic nanocomposites combine the distinct properties of the organic polymer and the inorganic filler, resulting in overall improved system properties. Monodisperse porous hybrid beads consisting of tetraethylene pentamine functionalized poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) particles and silica nanoparticles (SNPs) were synthesized under Stoeber sol-gel process conditions. A wide range of hybrid organic/silica nanocomposite materials with different material properties was generated. The effects of n(H2O)/n(TEOS) and c(NH3) on the hybrid bead properties particle size, SiO2 content, median pore size, specific surface area, pore volume and size of the SNPs were studied. Quantitative models with a high robustness and predictive power were established using a statistical and systematic approach based on response surface methodology. It was shown that the material properties depend in a complex way on the process factor settings and exhibit non-linear behaviors as well as partly synergistic interactions between the process factors. Thus, the silica content, median pore size, specific surface area, pore volume and size of the SNPs are non-linearly dependent on the water-to-precursor ratio. This is attributed to the effect of the water-to-precursor ratio on the hydrolysis and condensation rates of TEOS. A possible mechanism of SNP incorporation into the porous polymer network is discussed.

Quercetin-loaded nanocomposite microspheres for chronologically promoting bone repair via synergistic immunoregulation and osteogenesis

Biomaterial implantation for bone defect repair is a complex cascade reaction process, which mainly includes early inflammatory response and subsequent osteogenic repair. In this work, quercetin / nano-hydroxyapatite / poly (glycolide-co-epsilon-caprolactone) (Que/n-HA/PGCL) nanocomposite microspheres were successfully prepared by airflow shearing method, possessing interconnected porous structure with unique “eyeball-like” surface morphology. The encapsulation efficiency of microspheres reaches as high as 80 % and Que release was stable and continuous, only released 7.5 % at 120 h in the 4 wt% group. Moreover, Que-loaded microspheres triggered positive immunomodulation via upregulation of M2 macrophage polarization evidenced by decreased expression of pro-inflammatory cytokines TNF-α, iNOS and the increased expression of anti-inflammatory cytokines Arg1, IL-10 in RAW264.7 cells, which was beneficial to BMSCs osteogenic differentiation in the co-culture system. Meanwhile, the capability to directly promote osteo-differentiation was manifested by upregulation of Runx2, ALP, OPN, OCN gene expression and the increase of differentiation markers. Furthermore, the assessment of Que/n-HA/PGCL microspheres in vivo confirmed desirable bone repair contributed to efficient immunomodulation and excellent osteo-differentiation. Thus, the Que/n-HA/PGCL microspheres could serve as potential functional filling materials for bone repair, which could be applied to efficient drug delivery platform in the future clinical applications.

Enhanced photocatalytic activity of hierarchical C/ZnO nanocomposite derived from solvothermally restructured Zn-BTC microspheres

Single step solvothermal synthesis of hierarchical and hollow microspheres (HHMs) assembly of 1D zinc-trimesic acid (Zn-BTC) MOF nanospikes, without using any external stabilizer as shape modifier is reported here. Detailed electron microscopy imaging revealed that the Zn-BTC HHMs form through a self-templating mechanism due to the typical reaction conditions. The Zn-BTC HHMs were annealed to form ZnO/C hierarchical nanocomposite microspheres (HNMs). HNMs were found to be quite active for the photocatalytic water remediation through the photo-oxidation of dyes as well as photo-reduction of Cr (VI). Thorough characterization revealed that the HNMs exhibited three-dimensional (3D) hierarchical morphology with comparatively higher mesoporosity, extended visible light absorption, and better separation of photogenerated charges (e-/h+), resulting in enhanced photocatalytic performance (0.40 and 1.89 mg·g−1·min−1 removal efficiency for MV and Cr (VI) respectively). The enhanced photocatalytic activities of the HNMs were found to be due to the synergism between carbon matrix and the well-dispersed ZnO quantum dots.

Synthesis of polypyrrole-modified Fe3O4/SiO2/TiO2 nanocomposite microspheres and their photocatalytic activity

A polypyrrole-modified Fe3O4/SiO2/TiO2 composite material was successfully synthesized on the FST surface by in situ polymerization of pyrrole. Structural, morphological and magnetic response of Fe3O4/SiO2/TiO2/PPy(FST/PPy) were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction pattern, Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy, etc. Through SEM images, the crystal sizes of the prepared FST/PPy nanoparticles were determined to be about 110 nm. The catalytic activity of FST/PPy was evaluated by the degree of decomposition of rhodamine B under ultraviolet and visible light, respectively. FST/PPy had the photocatalytic activity under the action of the light: the degradation rate of rhodamine B reached 92.8% and 63.5% after 3 h of UV and Vis light irradiation, respectively. Especially, compared with FST, the degradation rate has shown obvious improvement under the action of Vis light. Furthermore, FST/PPy photocatalyst could be easily recycled using a magnet.

Quercetin-Loaded Nanocomposite Microspheres for Chronologically Promoting Bone Repair Via Synergistic Immunoregulation and Osteogenesis

Quercetin-Loaded Nanocomposite Microspheres for Chronologically Promoting Bone Repair Via Synergistic Immunoregulation and Osteogenesis

Chitosan-magnesium aluminum silicate nanocomposite microspheres coated with poly(vinyl acetate phthalate) for controlled release of capecitabine

Chitosan-magnesium aluminum silicate nanocomposite microspheres coated with poly(vinyl acetate phthalate) for controlled release of capecitabine

Removal of heavy metals from aqueous solution using porous (Styrene-divinylbenzene)/CuNi bimetallic nanocomposite microspheres

The existence of elevated heavy metals concentrations in aqueous resources raised a problem of worldwide concern because of their toxic, bio-accumulating and non-biodegradable character. The presence of these heavy metals beyond the allowable limit can cause serious health hazards to humans and animals. Recent advances in nanotechnology have explored the use of bimetallic nanoparticles as an adsorbent in drinking water treatment systems and have received increasing interest. In the present study, a novel Porous(Styrene-divinylbenzene)/CuNi bimetallic nanocomposite microsphere was synthesised and a series of batch scale adsorption experiments were conducted to investigate the adsorption characteristics of Pb2+, Cd2+, Mn2+ and Zn2+. The effects of contact time, pH, adsorbent mass and initial metal concentration on the adsorption characteristics of adsorbent was explored. The results revealed that the removal efficiency of adsorbent increased with increase in contact time and adsorbent mass, and decreased with increase in initial metal concentration. Significant variations in adsorption were observed for different heavy metals and the highest adsorption was achieved for zinc and manganese. With increasing pH of the solution from 3 to 7, the removal percentage of all heavy metals were increased and the experimental maximum adsorption capacity of adsorbent was 15.60 mg Pb(II)/g, 5.28 mg Cd(II)/g, 22.42 mg Mn(II)/g and 20.57 mg Zn(II)/g respectively. Batch experiments indicate that the pseudo-first-order kinetic model is more appropriate to explain the adsorption kinetics and the Langmuir adsorption isotherm was closely fits to experimental data than the Freundlich model. It can be concluded therefore that Porous(Styrene-divinylbenzene)/CuNi bimetallic nanocomposite microspheres have great potential for removing heavy metals from water.

Fe3+-doped ordered mesoporous γ-Fe2O3/SiO2 microspheres as a highly efficient magnetically separable heterogeneous Fenton catalyst

Here, several γ-Fe2O3/SiO2 nanocomposite microspheres were synthesized, characterized and tested as magnetically separable heterogeneous catalysts in an advanced oxidation process. A strong relation between the structure and the activity of these materials was evidenced. Two parameters, including the porosity of the silica support and the doping of the material with Fe3+ ions in addition to the γ-Fe2O3 nanoparticles, were investigated. The structure of the catalytic materials was determined by the use of different methods, in particular SEM, TEM, XRD, N2 physisorption, magnetometry, UV–Vis spectroscopy and XPS. The results demonstrated that the irregular microporosity of the silica framework can be replaced by an ordered mesoporosity, adding a second surfactant during the synthesis. For the mesoporous material, it was observed that the additional Fe3+ are dispersed in the mesoporous silica framework as individual cations and small clusters of Fe(III) species. The materials were tested as heterogeneous Fenton catalysts on two model aqueous pollutants, methyl orange (MO) and reactive black 5 (RB5). It was observed that the oxidation and mineralization rates of the two dyes is significantly enhanced when a doped catalytic material is used. This effect is particularly strong with the mesoporous silica support. In addition, the doped mesoporous catalyst retained its activity for a large range of conditions. These improvements were attributed to the strong activity of the additional Fe(III) species, although the presence of the mesoporosity also plays a significant role.

Cellulose and chitosan based magnetic nanocomposite microspheres and its application

AbstractIn this work, a simple and green method is used to fabricate magnet nanocomposite microspheres (cellulose/chitosan/Fe3O4) based on cellulose/chitosan microsphere via the interaction between metal ions with chitosan. The results of Fourier transform infrared spectra and X‐ray diffraction indicated that the Fe3O4 nanoparticles were well‐fixed in the network of cellulose/chitosan microsphere as a result of the chelation role between chitosan and metal ions. Moreover, the morphology of Fe3O4 nanoparticle can be adjusted by changing the chitosan concentration of cellulose/chitosan microsphere. Most important, the catalytic performance of the nanocomposite magnet microsphere was studied, and the magnet nanocomposite microspheres with face‐centered cubic structure and less size of Fe3O4 nanoparticles have shown excellent catalytic performance. Based on their excellent catalytic properties, these magnet cellulose/chitosan/Fe3O4 microspheres have prospect applications in the field of biotechnology and environmental, and so on.

Assessment of nano-hydroxyapatite and poly (lactide-co-glycolide) nanocomposite microspheres fabricated by novel airflow shearing technique for in vivo bone repair

A novel airflow shearing method was introduced to prepare microspheres efficiently with precisely control of microsphere size and homogeneity. The effects of technical parameters in the formation of the microspheres, such as solution concentration, nozzle size and airflow strength, were investigated. By optimizing the technical parameters (8% PLGA concentration, 27–32 G nozzle size, 6–8 l/min airflow strength), nano-hydroxyapatite and poly(lactide-co-glycolide) nanocomposite (nHA/PLGA) microspheres with a diameter around 250 μm and up to 40 wt% nHA content was prepared successfully. Especially, the microspheres possessed revealed great homogeneity and unique “acorn” appearance with two sides: A hard smooth side as well as a crumpled rough side, generated in the preparation process. Furthermore, the nHA/PLGA microspheres' potential application in bone tissue engineering was studied. In vitro, enhanced proliferation and osteogenic differentiation of the MC3T3-E1 cells was observed on as-prepared nHA/PLGA microspheres with high nHA content. In vivo, the BV/TV value of the microspheres with 20 wt% nHA was up to 75% and similar to the clinical products' performance. Moreover, beside high nHA content, the rough porous surface leads to bone ingrowth, which plays an important role in accelerating bone repair. Therefore, airflow shearing method could be an effective approach to fabricate biocompatible microsphere, and the as-prepared microspheres showed unique surface state and bone repair ability and making them as potential candidates for bone tissue engineering and bone implantation clinical applications.