•Gas-assisted magnetic separation (GAMS) method for separating proteins was investigated.•The method combined magnetic separation with flotation.•High separation rate and good recovery rate were achieved under the optimal conditions.•High recovery was obtained by adjusting initial solution pH in GAMS process.•Large-scale recovery of protein-loaded magnetic particles would become possible.In this paper, gas-assisted magnetic separation (GAMS), a technique that combines magnetic separation with flotation, was investigated for the potential large-scale separation of proteins. The GAMS process includes adsorption of target proteins and magnetic separation to recover protein-loaded magnetic particles from the dilute biosuspension with the assistance of bubbles. Microsized ethylenediamine-functionalized poly(glycidyl methacrylate) superparamagnetic microspheres (MPMs) and bovine serum albumin (BSA) were used as a model system. The feasibility of GAMS for capturing BSA-loaded MPMs from an appropriate medium was shown. High recovery of BSA-loaded MPMs was obtained by simple adjustment of the initial solution pH without extra detergents and antifoaming agents. The GAMS conditions were consistent with the adsorption conditions, and no proteins were desorbed from the MPMs during this process. Under the optimal conditions, the separation rate and recovery percentage reached 410 mL/min and 98% in 0.61 min, respectively. Conformational changes of BSA during the GAMS process were investigated by fluorescence spectroscopy and circular dichroism spectrometry.

•A palladium(II) porphyrin complex was successfully immobilized on PMs surfaces.•The Pd-MTP/PMs catalyst gave higher GC yield in Heck reaction of iodobenzene with ethyl acrylate.•The catalyst showed better reusability with no Pd leaching in the Heck reaction.A novel Heck reaction catalyst consisting of a palladium(II) complex of meso-tetra(p-hydroxyphenyl)porphyrin (MTP) and cross-linked chloromethylated polystyrene microspheres (PMs) was successfully prepared via covalent ether bonds between the chloride groups in the PMs and the hydroxyl groups in MTP. The catalyst was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES). This polystyrene-supported palladium-complex was an efficient heterogeneous catalyst for cross-coupling of aryl iodides with ethyl acrylate. The reaction of iodobenzene and ethyl acrylate under N2 at 100 °C and a catalyst concentration of 0.1% gave a gas chromatography product yield of 99.8%, which is much higher than that achieved using a free palladium(II) complex of MTP as the catalyst (41.3%). The catalyst was recycled up to six times without significant loss of catalytic activity. These results suggest that the immobilized palladium(II)–MTP catalyst has potential applications in synthetic and industrial chemistry.

•The PEI-grafted polymer microspheres were prepared.•The adsorbent has a high adsorption capacity.•The adsorption rate is considerably fast.•The adsorbent has good reusability and selectivity.•The adsorption mechanisms were discussed.Polyethylenimine-grafted poly(glycidyl methacrylate) (PGMA–PEI) microspheres were prepared using the dispersion polymerization method and a two-step reaction with ethylenediamine (EDA) and polyethylenimine (PEI). The PGMA–PEI microspheres were then characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) and tested for their ability to remove hexavalent chromium (Cr(VI)) from an aqueous solution in batch tests. The results demonstrated that Cr(VI) adsorption depended significantly on pH. The optimized pH value for the Cr(VI) adsorption was 2.0. The adsorption isotherms of PGMA–PEI microspheres with Cr(VI) fit the Langmuir model. The maximum adsorption capacities were 460.83, 485.44 and 505.05 mg g−1 for PGMA–PEI600, PGMA–PEI1800 and PGMA–PEI10,172 microspheres, respectively. The adsorption reached equilibrium within 10 min and the experimental data fit the pseudo-second-order model. The obtained thermodynamic parameters (ΔG0, ΔH0 and ΔS0) showed that the adsorption of Cr(VI) was an endothermic and spontaneous process. Competition from coexisting ions of K+, Na+, Ca2+, Cu2+, Cl−, NO3−, H2PO4−, and HPO42− was insignificant except SO42−. The regeneration study revealed that PGMA–PEI microspheres could be repeatedly used with no significant loss of adsorption efficiency.

A stable drug carrier has been prepared by covalently coating magnetic nanoparticles (MNPs) with PEO–PPO–PEO block copolymer Pluronic P85. The particles were characterized by TEM, XRD, DLS, VSM, FTIR, and TGA. A typical product has a 15 nm magnetite core and a 100 nm hydrodynamic diameter with a narrow size distribution and is superparamagnetic with large saturation magnetization (57.102 emu/g) at room temperature. The covalently-coated Pluronic-MNPs (MagPluronics) were proven to be stable in different conditions, such as aqueous solution, 0.2 M PBS solution, and pH 13.5 solution, which would be significant for biological applications. Furthermore, MagPluronics also possess temperature-responsive property acquired from the Pluronic copolymer layer on their surface, which can cause conformational change of Pluronics and improve load and delivery efficiency of the particles. The temperature-controlled loading and releasing of hydrophobic model drug curcumin were tested with these particles. A loading efficiency of 81.3% and a sustained release of more than 4 days were achieved in simulated human body condition. It indicates that the covalently-coated MagPluronics are stable carriers with good drug-loading capacity and controlled-release property.Graphical abstractHighlights► The magnetic nanoparticles are covalently coated by Pluronic P85 as drug carriers. ► The synthesis route of the drug carriers is easy and green. ► The drug carriers are superparamagnetic, water-disperse, and temperature-responsive. ► The drug carriers greatly improve the solubility and bioavailability of curcumin. ► The drug carriers are more stable, biocompatible, and suitable for drug delivery.

In this study, gas-assisted superparamagnetic extraction (GASE), a novel technology that combined superparamagnetic extraction technology with flotation technology, was proposed for potential large-scale separation of proteins. GASE includes adsorption for trapping proteins, and flotation and high gradient magnetic separator (HGMS) for recovering proteins-loaded magnetic particles from the dilute biosuspension. Citrate-modified superparamagnetic nanoparticles (CMNs) and bovine serum albumin (BSA) were used as a model. The feasibility of flotation for these particles enrichment was demonstrated. The results indicated that the BSA-loaded CMNs could be well concentrated in either foaming flotation or nonfoaming flotation by simple adjustment of the initial solution pH, without extra detergents and operations. The flotation conditions were consistent with the adsorption ones, and no proteins were desorbed from CMNs in the GASE process. Under the optimal conditions, the enrichment ratio and recovery percentage reached 31 and 99% in 1.5 min, respectively.

In this study, gas-assisted superparamagnetic extraction (GASE) with potential large-scale application was proposed for selective separation of multicomponent proteins. Magnetic poly(glycidyl methacrylate)–iminodiacetic acid–Zn2+ microspheres (MPMs) for selective separation of bovine serum albumin (BSA) and bovine hemoglobin (BHb) are selected as a model. The feasibility of flotation for concentrating BHb-loaded MPMs from dilute mixed proteins solution was proved. The well-concentrated solution of BHb-loaded MPMs could be achieved by simple adjustment of pH values and ionic strength in low regions, without additive detergent. Impurity BSA had the effects of improving the flotability of BHb-loaded MPMs, acting as foaming agent, but decreasing the enrichment ratio in the GASE process. The flotation conditions and the selective adsorption ones showed strong consistency. Under the optimal conditions, the enrichment ratio of 39 and recovery percentage of 98% was obtained within 1.3 min. Furthermore, the enrichment ratio could be further improved by added flotation steps.

The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol–gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol–gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol–gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol–gel 2 sample.

A novel polyglycidylmethacrylate (PGMA) microspheres with high adsorption capacity of Cr(VI) was prepared by cerium(IV) initiated graft polymerization of tentacle-type polymer chains with amino group on polymer microspheres with hydroxyl groups. The micron-sized PGMA microspheres were prepared by a dispersion polymerization method and subsequently modified by ring-opening reaction to introduce functional hydroxyl groups. The polymer microspheres were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the polymer microspheres had an average diameter of 5 ìm with uniform size distribution. The free amino group content was determined to be 5.13 mmol·g−1 for g-PGMA-NH2 microspheres by potentiometric and conductometric titration methods. The Cr(VI) adsorption results indicated that the graft polymerization of tentacle-type polymer chains on the polymer microspheres could produce adsorbents with high adsorption capacity (500 mg·g−1). The polymer microspheres with grafted tentacle polymer chains have potential application in large-scale removal of Cr(VI) in aqueous solution.