Magnetic Cellulose Microspheres Research Articles

Novel High-efficiency adsorbent consisting of magnetic Cellulose-based ionic liquid for removal of anionic dyes

Exploiting a high-efficiency and environmental-protection absorbent to catch organic dyes from aqueous solution is a practical exploration to carry out the vision of Green and Sustainable Development. In this paper, we studied a functionalized porous magnetic cellulose-based ionic liquid adsorbent (FSIL@CP) to rapidly and vastly uptake anionic dyes. The FSIL@CP composites consisted of two parts, namely synthesis of Fe3O4 nanoparticles grafted by imidazole ionic liquid and subsequent formation of porous magnetic cellulose microspheres modified by amino-rich polyethyleneimine. The structure of FSIL@CP was characterized by SEM, TEM, XRD, XPS, BET, TGA, VSM and FTIR. The adsorption performances of the FSIL@CP towards anionic dyes were evaluated via the experiments of various influence factors, adsorption kinetics, isotherm and thermodynamics. The maximun adsorption capacities for Congo red (CR) and Methyl blue (MB) reached 1299.3 and 1068.1 mg g−1, respectively, which is better than other similar adsorbents reported in the literature. The adsorption kinetics and isotherm models were well-fitted to pseudo-second-order model and Langmuir isotherm, and the adsorption process followed multiple-stage intraparticle diffusion with spontaneous feature. The adsorbent can be rapidly and easily separated from aqueous solution under external magnetic field. The regeneration performance of the adsorbent is excellent and could be repeatedly used. From the results, the FSIL@CP adsorbent offers an effective, inexpensive and reusable/sustainable system for removal and remediation of anionic dyes such as CR and MB in dye wastewater.

Lipase immobilization on magnetic cellulose microspheres for rapid screening inhibitors from traditional herbal medicines

With a dramatic increase in the incidence of obesity, it is significant to screen lipase inhibitors from traditional herbal medicines as drugs to treat obesity. Lipase inhibitors currently used to treat obesity possess the defects of toxicity and off-target effects. Thus, there is an urgent need to explore more safe, effective and targeted anti-obesity drugs from traditional herbal medicines. In this work, amino functionalized magnetic cellulose microsphere was employed as a novel support to immobilize lipase through covalent bonding. Characterizations from fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction demonstrated the successful preparation of the support. In comparison with the free lipase, the immobilized lipase manifested the excellent properties of a wider range for pH and temperature endurance, better pH, thermal, storage stability and reusability. Through investigating the kinetics performances of the immobilized lipase, the Michaelis-Menten constant was calculated to be 2.05 mM and its inhibition constant for orlistat was ascertained to be 40.74 μM. Eventually, the established strategy was applied to screen lipase inhibitors from 7 traditional herbal medicines and Crataegus pinnatifida Bunge was screened out due to its significant lipase inhibitory activity. To sum up, our newly established method not only developed a platform for efficiently discovering novel anti-obesity drugs from traditional herbal medicines, but also laid a solid foundation for successfully exploring undiscovered medicinal value of the traditional herbal medicines.

Transesterification of tree-born oil with novel magnetic biobased heteropolyacid prepared via in-situ reaction

An active and recyclable magnetic biobased heteropolyacid catalyst (HPW-MCMs) was prepared for the high yield of transesterification of Pistacia chinensis seed oil (PCO). The magnetic cellulose microspheres (MCMs) were used as the supporter, and the phosphotungstic acid (HPW) was synthesized in surface and micropores via in-situ reaction. Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and diffraction of X-ray (XRD) were fully used to characterize the catalyst. Furthermore, the conditions of 600 W of microwave power, 65 °C of temperature, 6 wt. % of catalyst amount, 8 of methanol/oil ratio and 30 min of reaction time were selected as the optimal conditions. Under the conditions, a high conversion of 96.6 % could be obtained. The HPW-MCMs could also be recovered conveniently and efficiently recycled for six cycles. Therefore, the prepared HPW-MCMs would be potentially useful for the efficient and economic transesterification reaction of PCO.

Fabrication of magnetic cellulose microspheres by response surface methodology and adsorption study for Cu (II)

Regenerated cellulose microspheres have many characteristics and have been applied in many areas. In this study regenerated magnetic cellulose microspheres were prepared by mixing the cellulose solution and Fe3O4 nanoparticles, followed by emulsification and precipitation. The microspheres exhibited porous structure with rough surface and are nearly superparamagnetic. Effect of ratio of cellulose solution and liquid paraffin, stirring speed and amount of emulsifying agent on particle size were evaluated by response surface methodology and amount of emulsifying agent was found the most influential variable. A valid model was established to predict the response and magnetic particles with controlled size in the range of 50–900 μm could be fabricated by varying the dispersion parameters. The adsorption of Cu (II) on the microspheres was also investigated and it could be described by Langmuir model. Besides, both pseudo-first-order and pseudo-second-order models were applicable to describe the adsorption kinetics and process could be divided into adsorption on surface of the microspheres and intraparticle diffusion with film diffusion involved.

In Situ Synthesis of Ag–Fe3O4 Nanoparticles Immobilized on Pure Cellulose Microspheres as Recyclable and Biodegradable Catalysts

The preparation of reusable and eco-friendly materials from renewable biomass resources such as cellulose is an inevitable choice for sustainable development. In this work, cellulose was dissolved in 7 wt % NaOH/12 wt % urea aqueous solution at −12 °C with rapid stirring. Cellulose microspheres (Cels) were fabricated by a sol–gel transition method. Subsequently, novel magnetic Ag–Fe3O4 nanoparticles (NPs) supported on cellulose microspheres were successfully constructed by an in situ one-pot synthesis. The magnetic cellulose microspheres (MCels) displayed a spherical shape with mesoporous structure and had a narrow particle size distribution (10–20 μm). Many nanopores with a pore diameter of 5–40 nm were observed in MCels. The Ag–Fe3O4 NPs were immobilized by anchoring with the hydroxyl groups on the surface of Cels. MCels were applied as a microreactor to evaluate their catalytic activities. 4-Nitrophenol (4-NP) could be reduced to 4-aminophenol (4-AP) in 5 min, catalyzed by MCels. Moreover, the magnetic microspheres exhibited a small hysteresis loop and low coercivity. Thus, MCels could be quickly gathered in water under a magnetic field in 10 s, as well as almost 9 cycle times, maintaining relatively high catalytic activity. In this work, cellulose matrix as the catalyst support could be biodegraded completely in the environment. It provided a green process for the utilization of biomass in nanocatalytic applications.

Immobilized lysozyme onto 1,2,3,4-butanetetracarboxylic (BTCA)-modified magnetic cellulose microsphere for improving bio-catalytic stability and activities

Novel carboxyl-functionalized core-shell magnetic cellulose microspheres (MCMS) were prepared by surface modification with 1,2,3,4-butanetetracarboxylic acid (BTCA) and then applied in the immobilization of lysozyme via covalent bonding. The successful preparation of particles has been verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Fourier-transform infrared spectroscopy (FTIR) techniques. The optimal temperature and pH of the immobilized lysozyme were shown to be respectively 40 °C and 7. The immobilized lysozyme exhibited excellent performances within wide pH and temperature ranges as well as the high storage and thermal stabilities compared to free lysozyme. The apparent kinetic characterization of immobilized lysozyme revealed that its Km value was 1.37 times higher than that of free lysozyme and that its Vmax was slightly lower. The immobilized lysozyme demonstrated an acceptable reusability and showed 51.9±2.2% of activity after six cycles. This study demonstrated the application potential of BTCA-modified MCMS as an immobilized carrier for lysozyme.

Development of Cellulose Hydrogel Microspheres for Lipase Immobilization

Cellulose hydrogel microspheres were prepared by sol-gel transition using an ionic liquid-in-oil emulsion. Factors that influenced the formation of these microspheres, including the ratio of ionic liquid to oil, surfactant concentration, and stirring speed, were optimized for lipase immobilization. Using the optimized method, Candida rugosa lipase was efficiently immobilized on the microspheres by physical adsorption. As compared with the free lipase, the specific activity of the immobilized lipase was 1.4 times higher, its half-life at 45°C was 41 times longer, and it showed an enhanced stability over a wide pH range. The lipase immobilized on cellulose microspheres showed a much higher loading efficiency, immobilization yield, and specificity constant than lipase immobilized on microcrystalline cellulose or millimeter-sized hydrogel beads. To increase the reusability of cellulose microspheres as an enzyme support material, magnetic cellulose microspheres were also prepared by adding Fe3O4. The lipase immobilized on magnetic cellulose microspheres was simply recovered using a magnet and continuously reused with a minimal loss of activity.

Fabrication of cellulose based superhydrophobic microspheres for the production of magnetically actuatable smart liquid marbles

Cellulose microspheres were fabricated on the basis of sol-gel transition using NaOH/urea/H 2 O as the solvent system. These microspheres had an average diameter of about 30 μm. Upon modification with Fe 3 O 4 and poly (DOPAm- co -PFOEA), superhydrophobic magnetic cellulose microspheres were generated, which were analyzed by FTIR, TG, XRD, XPS and water contact angle tests. Magnetic cellulose microspheres contained approximately 15 wt% of Fe 3 O 4 . Poly(DOPAm- co -PFOEA)/Fe 3 O 4 /cellulose microspheres and had a low surface energy and a high water-repellency. These superhydrophobic microspheres were also converted into liquid marbles via an easily scalable process.

Multifunctional Magnetic Cellulose Surface-Imprinted Microspheres for Highly Selective Adsorption of Artesunate

Molecularly imprinted magnetic cellulose microspheres (MIP-MCM) of artesunate (Ars) are developed by a surface functional monomer-directing system. MIP-MCM are obtained by coating a layer of MIP on the surface of the cellulose and Fe3O4 composite microspheres. The composite materials are characterized by Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), UV–vis spectrophotometry (UV), dynamic light scattering (DLS), and magnetic resonance imaging (MRI). They are adsorption-selective to Ars, highly regenerate, and stable in wide pH and temperature ranges. The adsorption of Ars reaches equilibrium within 10 h, and the maximum adsorption quantity is as high as 0.22 mg/mg, much better than previous reports. Through the Langmuir–Freundlich isotherm and pseudo-second-order kinetic model, the adsorption kinetics and thermodynamics of MIP-MCM were studied. The thermodynamic studies suggest that the adsorption of Ars on MIP-MCM is a spontaneous process. ...

Characterization of Magnetic Cellulose Microspheres Reconstituted from Ionic Liquid

Magnetic Fe3O4/cellulose microspheres with mean diameter of 100 μm were prepared by sol-gel transition method using ionic liquids (AmimCl) as solvent for cellulose dissolution and regeneration. Their structure , properties and morphology were analysed using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer. The results indicated that the synthesized microspheres were good sphere with a mean diameter of about 100 μm. It also showed that cellulose had been successfully covered onto the surface of Fe3O4 after the preparation. Therefore, we have provided a simple and biocompatible support for applications in the biomaterials field.

Immobilization of Penicillin G Acylase in Epoxy-Activated Magnetic Cellulose Microspheres for Improvement of Biocatalytic Stability and Activities

We prepared magnetic cellulose porous microspheres (MCM) with mean diameter of ∼200 μm by employing the sol-gel transition (SGT) method from a mixture of magnemite ferrofluid and cellulose dissolved in 7 wt % NaOH/12% urea aqueous solvent precooled to -12 °C. Subsequently, the cellulose microspheres were activated with epoxy chloropropane to enhance loading efficiency of biomacromolecules. Their morphology, structure, and properties were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and vibrating-sample magnetometer. The results indicated that the spherical magnetic γ-Fe2O3 nanoparticles with mean size of 10 nm were uniformly dispersed and embedded in the cellulose substrate of MCM, and the structure and nature of γ-Fe2O3 were conserved perfectly. Penicillin G acylase (PGA) as a biocatalyst was immobilized successfully in the porous microspheres, as a result of the existence of the cavity and affinity forces in the activated cellulose matrix. The immobilized PGA exhibited highly effective catalytic activity, thermal stability, and enhanced tolerance to pH variations. Furthermore, the cellulose microspheres loaded with the enzymes could be removed and recovered easily by introducing a magnetic field, leading to an acceptable reusability. Therefore, we have provided a simple and biocompatible support for the enzyme immobilization, which will be promising for the applications in the biomaterial fields.

Preparation of Cellulose Magnetic Microspheres with “The Smallest Critical Size” and Their Application for Microbial Immunocapture

The goal of this paper is to introduce a universal method for quantitative control of the particle size of magnetic cellulose microspheres (MCMS) and to produce an optimal antibody absorption capability as an aid in the research of new applications of MCMS in immunomagnetic capture. In this study, "the smallest critical size theory" (TSCS) was proposed, tested, and confirmed by IgG-carrying capability measurements, magnetic response analysis, immunomagnetic capture, and PCR identification of bacteria. A Gaussian expression was proposed and used to guide the preparation of MCMS of the smallest critical size (SCS). The results showed that the diameter of the SCS of MCMS in this study was 5.82 mum, while the IgG absorption capability of the MCMS with SCS was 186.8 mg/mL. In addition, its high sensitivity and the efficiency of immunomagnetic capture of Salmonella bacteria exhibited another new application for MCMS.

Preparation of novel magnetic cellulose microspheres via cellulose binding domain–streptavidin linkage and use for mRNA isolation from eukaryotic cells and tissues

We have developed micron-sized magnetic cellulose microspheres (MCMS), biospecifically coated with streptavidin (SA) using a novel cellulose binding domain and SA fusion protein, to harvest mRNA from eukaryotic cells and tissues. Biospecific connection between SA and MCMS exhibited significant advantages compared with traditional chemical coupling, including convenient and simple preparation, elimination of toxic compounds, and highly efficient extraction of a pure target molecule. To confirm compatibility, mRNA isolated from cell or tissue samples was used for amplification of housekeeping genes ( GAPDH and β-actin) and specific target genes (two fragments V H and V L from the variable fragments of IgG and the gene encoding GLP-1 receptor). Preliminary studies predict that this novel method has potential in future developments in target gene isolation and DNA manipulation.

Preparation of novel immunomagnetic cellulose microspheres via cellulose binding domain-protein A linkage and its use for the isolation of interferon α-2b

We have developed a novel method for immobilizing antibodies onto magnetic cellulose microspheres (MCMS) using a cellulose binding domain-protein A (CBD-ProA) linkage. Biospecific connection between antibodies and MCMS exhibited significant advantages compared to chemical coupling, including convenient and simple preparation, elimination of toxic compounds, and highly efficient antibody utilization. To evaluate the application of this method, interferon α-2b (IFN α-2b) was chosen as a model target for detailed analysis of method parameters, such as protein adsorption, antibody efficiency, and reproducibility of the matrix. After optimization and characterization, IFN α-2b was successfully purified from crude cell lysate in a single step by cross-linked anti-IFN α-2b IgG protein A-CBD-MCMS, purifying 106.1 μg IFN α-2b/mL matrix, corresponding to a 13-fold increase over the chemical coupling method. Size-exclusion HPLC identified that the IFN α-2b isolated by this method had an overall purity of 95.5%, while immunological and biological assays showed an activity recovery of 91.9% and specific antiviral activity of 2.67 × 10 8 IU/mg. Overall, this study effectively illustrates the favorable qualities of this immobilization method with precisely defined properties that provide an attractive strategy for developing large-scale purification suitable for targeting compounds in highly complex samples.

Immobilization Staphylococcal Protein A on Magnetic Cellulose Microspheres for IgG Affinity Purification

The main objective of this study is to develop and evaluate the immobilization of Staphylococcal Protein A on magnetic cellulose microspheres (SPA-MCMS) for immunological capture of IgG. After cloning, expression and separation, SPA was immobilized onto MCMS to prepare a magnetic affinity media subject to the purification of IgGs. The binding capacity, binding time, leakage of SPA and its reproducibility were optimized to improve the binding efficiency with an appropriate amount and recovery of IgG. Rabbit IgG was successfully purified from serum in a single-step by SPA-MCMS with an overall recovery of 73.18% and purity of 90.27%. Therefore, this study effectively illustrated the advantages of magnetic microcarriers for rapid and efficient purification of antibodies. The separation media shows a high potential for the future development of affinity isolation and immunodiagnostic application.

Preparation and characterization of magnetic microspheres for the purification of interferon α-2b

Magnetic agarose microspheres (MAMS), magnetic cellulose microspheres (MCMS), and magnetic poly(vinyl alcohol) microspheres (MPVAMS) were prepared by various different preparation methods. MCMS coupled with anti-IFN alpha-2b monoclonal antibodies (mAb) were selected for the purification of interferon alpha-2b (IFN alpha-2b) after performance characterization among microspheres. Parameters of immunomagnetic separation (IMS), including binding mAb, elution behavior, and sample pretreatment conditions, were optimized to improve the purification efficiency of the separation of IFN alpha-2b by MCMS. Size-exclusion HPLC (HPSEC) showed that the IFN alpha-2b was purified from crude cell lysate had an overall purity of 92.9%, while immunological and biological assays showed an activity recovery of 88.5% and specific antiviral activity of 2.7 x 10(8) IU/mg. Identity and molecular mass of purified IFN alpha-2b were confirmed by western blot and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis. This study illustrated the favorable separation media which combined desired properties for the development of magnetic separation of biological materials.