A novel approach to the synthesis of highly monodisperse quantum dot-loaded polymer beads by combining impregnation and precipitation techniques was reported. The monodisperse poly(glycidyl methacrylate) (PGMA) beads were first synthesized by dispersion polymerization. Then, the PGMA beads were chemically modified to generate carboxyl groups, and impregnation of cadmium ions (Cd2+) inside the beads. Subsequently, the cadmium ions were reacted with thioacetamide to form cadmium sulfide (CdS) quantum dots within the polymer beads. The morphology, structure, and properties of CdS quantum dot-loaded polymer beads were studied by field emission scanning electron microscope (SEM), transmission electron microscope, fluorescence spectrophotometer, fluorescence microscope, Fourier transform infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. The results indicated that the CdS quantum dot-loaded polymer beads had an average size of 1.4 m, and were highly monodisperse. More interestingly, the CdS quantum dots distributed evenly within the polymer beads, which provide very strong fluorescence intensity. The existence of carboxyl groups on the quantum dot-loaded polymer beads was measured quantitatively, and was found to be 0.2 mmol/g. These CdS quantum dot-loaded polymer beads involving functional carboxyl groups would have potential applications in biological immunoassay and photoelectronic fields. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 2294-2300

A novel method for the preparation of monodisperse porous silica microspheres with controllable morphology and structure is reported. The starting porous polymer microspheres were first functionalized with ethylenediamine (EDA) to generate amino groups. Subsequently, silica nanoparticles were deposited in the porous polymer microsphere to form polymer/silica hybrid microspheres via a modified sol-gel process in the presence of tetra-n-butylammonium bromide (TBAB) or tetramethyl ammonium hydroxide (TMAH). Upon calcination of the polymer/silica hybrid microspheres, the porous silica microspheres were obtained. The morphology, inner structure, and properties of the porous silica microspheres were studied by field emission scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mercury intrusion method. The results show that the presence of TBAB or TMAH in the process not only prevents the agglomeration of the hybrid microspheres, but also governs the controllable morphology from a porous inner structure to a hollow-cage structure. The obtained porous silica microspheres exhibit no shrinkage from the polymer microspheres with a yield of around 98%. These porous silica microspheres have potential applications in the fields of chromatography, catalyst, and biology. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The purpose of this study is to develop a rapid and efficient purification method for determination of veterinary drug based on magnetic silica nanospheres. We have described a scheme for preparing C18/C8-functionalized magnetic silica nanospheres (Fe3O4@Si-C8/C18) for potential use as capture probes in sample pretreatment. The magnetic Fe3O4 particles were firstly coated by tetraethyl orthosilicate to form magnetic silica nanospheres, which were then modified by both trimethoxy(octadecyl)silane (C18) and trimethoxy(octyl)silane (C8). The Fe3O4@Si-C8/C18 thus prepared could exhibit strong superparamagnetism, highly efficient capture ability, easy-to-use for isolation, and enrichment of veterinary drug residues in food.

将Fe3O4@Si-C8/C18复合磁性纳米材料应用于食品安全中的兽药净化领域,采用共沉淀法制备磁性纳米前躯体,并在乙醇相中进行表面硅化处理及（辛基三甲氧基硅烷）C8/（十八烷基三甲氧基硅烷）C18表面修饰,经透射电镜、X射线、磁性能分析、红外光谱等手段对所制备的复合磁性纳米进行表征,所制备的磁性纳米大小均匀,粒径在100～1000nm范围内可调,经多重修饰后的Fe3O4@Si-C8/C18复合磁性纳米材料其磁性强度没有明显降低,并具有表面富集功能。为考察这种磁性纳米材料在兽药提取中的应用,选取豆芽中氯霉素残留的净化来进行初步研究,结果表明所制备的复合型磁性纳米材料在小分子净化富集中展现出广阔的应用价值,尤其在食品安全领域。

A novel and effective method for the preparation of monodisperse CdS quantum dot-polymer microspheres was proposed. The monodisperse hollow polymer microspheres were firstly swelled in chloroform. Then, the reaction precursor composed of CdO and sulfur, was impregnated into the hollow polymer microspheres. Subsequently, the CdS quantum dots were synthesized directly within the polymer microspheres by thermal decomposition. The morphology, structure, and fluorescence properties of CdS quantum dot-polymer microspheres were studied by scanning electron microscope, transmission electron microscope, fluorescence microscope, and flow cytometry. The results indicate that the fluorescent CdS quantum dots are successfully synthesized in the monodisperse hollow polymer microspeheres, which provide very strong fluorescence intensity, and offer excellent photostability due to the compact structure of the polymer matrix. These CdS quantum dot-polymer microspheres have potential applications in biotechnology and biomedicine. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 751-755, 2010

A novel and effective method for the preparation of monodisperse CdS quantum dot-polymer microspheres was proposed. The monodisperse hollow polymer microspheres were firstly swelled in chloroform. Then, the reaction precursor composed of CdO and sulfur, was impregnated into the hollow polymer microspheres. Subsequently, the CdS quantum dots were synthesized directly within the polymer microspheres by thermal decomposition. The morphology, structure, and fluorescence properties of CdS quantum dot-polymer microspheres were studied by scanning electron microscope, transmission electron microscope, fluorescence microscope, and flow cytometry. The results indicate that the fluorescent CdS quantum dots are successfully synthesized in the monodisperse hollow polymer microspeheres, which provide very strong fluorescence intensity, and offer excellent photostability due to the compact structure of the polymer matrix. These CdS quantum dot-polymer microspheres have potential applications in biotechnology and biomedicine.

A novel process for the preparation of monodisperse magnetic polymer microspheres by uniquely combining swelling and thermolysis technique was reported. The monodisperse polystyrene microspheres were first prepared by dispersion polymerization and swelled in chloroform. Then, ferric oleate was dispersed in chloroform as a precursor and impregnated into the swollen polymer microspheres. Subsequently, the iron oxide nanoparticles were formed within the polymer matrix by thermal decomposition of ferric oleate. The morphology, inner structure, and magnetic properties of the magnetic polymer microspheres were studied with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), and superconducting quantum interference device (SQUID) magnetometer. The results showed that the average diameter of the magnetic polymer microspheres was 5.1 microm with a standard deviation of 0.106, and the magnetic polymer microspheres with saturation magnetization of 12.6 emu/g exhibited distinct superparamagnetic characteristics at room temperature. More interestingly, the magnetite nanoparticles with a spinel structure are evenly distributed over the whole area of the polymer microspheres. These magnetic polymer microspheres have potential applications in biotechnology.

A new approach to the surface functionalization of magnetic polystyrene microbeads with chloroacetyl chloride in the presence of aluminum chloride was reported. Composite microbeads consisting of polymer-coated iron oxide nanoparticles were prepared by spraying suspension polymerization. Functional chloride groups were introduced onto the sur face of magnetic polystyrene microbeads by surface chemical reaction without destroying the magnetite nanoparticles within the microbeads. First, a complex was synthesized by a reaction between aluminum chloride and chloroacetyl chloride. Then, the complex was added dropwise to the solution of magnetic polystyrene microbeads, and a surface acylation reaction between complex and polystyrene microbeads was carried out. Subsequently, the amino groups were coupled to the magnetic microbeads via an ammonolysis reaction between ethylenediamine and chloride groups on the. acylated magnetic polystyrene microbeads. The chemical composition, surface functional groups, and magnetism of the magnetic polystyrene microbeads before and after surface functionalization were characterized by Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results showed that the surface functionalization reaction had little impact on the magnetism of the microbeads. The content of surface amino groups on the magnetic polystyrene microbeads was found to be 0.2 mmol/g. An affinity dye, Cibacron Blue F3G-A (CB), was then immobilized to prepare a magnetic affinity adsorbent. It was confirmed from X-ray photoelectron spectroscopy spectra that, the CB molecules were covalently coupled on the magnetic microbeads.

A novel protocol for preparing magnetic poly(vinyl alcohol) (PVA) beads by reverse spray suspension crosslinking was reported. The hydrophilic Fe3O4 nanoparticles were mixed with PVA, glutaraldehyde, and water to form aqueous phase. Then the aqueous phase was sprayed into vegetable oil by a pressure of nitrogen gas to form water in oil (W/O) suspension. The magnetic PVA beads were obtained in the presence of hydrochloric acid catalyst. It was found that the magnetic PVA beads obtained good properties when the PVA concentration was 10%, and the oil phase temperature was controlled at 40 degrees C. The mechanical stirring has little impact on the size of magnetic PVA beads in the process of reverse spray suspension crosslinking. The Cibacron Blue (CB) was coupled on the surface of magnetic PVA beads by surface chemical reaction. The morphology, size, and magnetic properties of the magnetic PVA beads were examined by scanning electron microscopy, laser diffraction, and vibrating sample magnetometer, respectively. Compared with the stirring method, it was found that the size of magnetic PVA beads was monodisperse and their saturation magnetization was much higher. Fourier transform infrared and X-ray photoelectron spectroscopy experimental results proved that CB molecules were covalently immobilized onto the surface of the magnetic PVA beads. Meanwhile, the protein affinity separation experiments demonstrated that the magnetic PVA beads can potentially be used as a carrier for large-scale protein separation. (c) 2007 Wiley Periodicals, Inc.

To circumvent the problem of reduction of the supermagnetic properties of superparamagnetic iron oxide (SPIO) nanoparticles after chemical modification to conjugate targeting molecules, we have adapted a tumor-targeting nanoimmunoliposome platform technology (scL) to encapsulate and deliver SPIO (scL-SPIO) in vitro and in vivo without chemical modification. Scanning probe microscopy, confocal microscopy, and Prussian blue staining were used to analyze the scL-SPIO and assess intracellular uptake and distribution of SPIO in vitro. In vivo targeting and tumor-specific uptake of scL-SPIO was examined using fluorescent-labeled SPIO. We demonstrated that SPIO encapsulation in the scL complex results in an approximately 11-fold increase in SPIO uptake in human cancer cells in vitro, with distribution to cytoplasm and nucleus. Moreover, the scL nanocomplex specifically and efficiently delivered SPIO into tumor cells after systemic administration, demonstrating the potential of this approach to enhance local tumor concentration and the utility of SPIO for clinical applications.

Monodisperse magnetic spheres with multifunctional groups were synthesized by spraying suspension polymerization. The effects of stabilizer type and its concentration on the monodispersity of magnetic spheres were investigated. The results showed that polyvinyl alcohol (PVA) was satisfactory as a stabilizer in this spraying suspension polymerization, and the magnetic spheres showed good monodispersity when the concentration of PVA was increased to above 20wt%. It was also found that the monodispersity of magnetic spheres could be improved with increase of the amount of initiator. Scanning electron microscopy and vibrating sample magnetometer verified that the magnetic spheres obtained were monodisperse with small size (about 9.8μm) and displayed superparamagnetic characteristics. Data of Fourier transform infrared (FT-IR) spectroscopy and surface chemical reaction method indicated that the extensive epoxy groups existed on the surface of magnetic spheres. Bovine serum albumin (BSA) was covalently immobilized onto the glutaraldehyde treated and untreated magnetic spheres, respectively. The results showed that the maximum BSA immobilization capacity onto the magnetic spheres was about 57mg/g.

Superparamagnetic functional carriers to obtain high selectivity were reported in this study. Magnetic carriers with epoxy groups were synthesized by spraying suspension polymerization (SSP). The measurement of scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) showed that the magnetic carriers have a narrow size distribution and displayed superparamagnetic characteristics. The magnetic carriers with epoxy groups were modified by various affinity ligands to magnetic functional carriers such as copper-IDA carriers, benzamidine carriers and phenylboronic acid carriers. The effects of medium pH and subtilisin Carlsberg concentration on adsorption capacity were investigated. It was found that phenylboronic acid and benzamidine immobilized magnetic carriers were effective magnetic carriers for affinity adsorption of subtilisin Carlsberg, and the maximum adsorption capacity (about 65mg/g) was obtained at pH 9.5. The adsorbed subtilisin Carlsberg was also desorbed successfully by using dissociation agents, and the recovery of the enzyme activity was still around 85%.

An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

Moderately uniform magnetic poly(methylmethacrylate–divinylbenzene–glycidylmethacrylate) microspheres (poly(MMA–DVB–GMA) microspheres) were prepared by spraying suspension copolymerization of methyl methacrylate, divinylbenzene and glycidyl methacrylate in the presence of Fe3O4 magnetic fluid. A protein adsorption assay indicated that these magnetic microspheres could significantly improve the capacity of protein adsorption.

The effect of phenylboronic acid, a competitive inhibitor, on the extraction process and activity recovery of α-chymotrypsin by AOT[sodium 1,4-bis(2-ethylhexyl) sulfusuccinate] reverse micelles was studied. A moderate increase of extraction and in significant change of stripping were found when 2 mmol/L phenylboronic acid was added into the AOT reverse micelles system. The profound effect was that the activity recovery was greatly enhanced. The stability of enzyme activity was time dependent: the addition of phenylboronic acid induced enhanced activity recovery in a prolonged contact time during extraction and stripping. The specific binding of phenylboronic acid to chymotrypsin was considered to account for the stabilizing effect of enzyme activity during reverse micelles extraction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A spraying suspension polymerization process for preparation of magnetic polystyrene microspheres with a narrow size distribution was proposed. The magnetite (Fe3O4) nanoparticles with hydrophobic shell were first prepared by a modified chemical coprecipitation method. Then the oil solution, composed of monomer styrene, crosslinker divinylbenzene, Fe3O4 nanoparticles, and initiator benzoyl peroxide, was sprayed into the poly(vinyl alcohol) aqueous solution by a pressure of nitrogen gas to form droplets. Finally, the droplets would be polymerized rapidly to magnetic polystyrene microspheres at the polymerization temperature. The morphology and magnetic properties of microspheres were examined using a scanning electron microscope and a vibrating sample magnetometer. The results showed that the magnetic microspheres had a narrow size distribution with mean diameter of around 10 mu m and smooth surface, and the magnetic microspheres with saturation magnetization of 15.6 emu/g exhibited distinct superparamagnetic characteristics. Powder X-ray diffraction was used to investigate the structure of the magnetite nanoparticles dispersed in the polystyrene matrix. (c) 2005 American Institute of Chemical Engineers.

开发了一种制备磁性高分子微球的喷流式悬浮聚合反应新方法.在疏水性Fe3O4磁流体存在下,以甲基丙烯酸甲酯(MMA)为聚合单体,二乙烯苯(DVB)为交联剂,过氧化苯甲酰(BPO)为引发剂,聚乙烯醇(PVA)为稳定剂,采用喷流式悬浮聚合法制备了磁性聚甲基丙烯酸甲酯(PMMA)微球,并对制备的磁性微球进行了表面修饰.采用振动样品磁强计(VSM)和扫描电子显微镜(SEM)检测了磁性微球的磁性能和形貌,红外光谱检测了微球表面的活性功能基团.结果表明磁性微球的比饱和磁化强度为16.8 emu/g,表现为超顺磁性,微球的尺寸为10 μm,且大小比较均一.

A novel method for preparation of magnetic polymer microspheres by spraying suspension polymerization (SSP) was developed. Relatively uniform magnetic poly(methyl methacrylate) microspheres were prepared by the spraying suspension polymerization (SSP) using methyl methacrylate (MMA) as monomer, divinylbenzene (DVB) as cross-linking agent, benzoyl peroxide (BPO) as initiator and polyvinyl alcohol (PVA) as stabilizer in the presence of hydrophobic Fe3O4 magnetic fluid. The microspheres prepared were modified by surface chemical reaction. The magnetic properties and morphology of the microspheres were examined by SEM and VSM respectively. The active functional groups of microspheres were examined by infrared spectra. The results showed that microspheres with saturation magnetization of 16.8 emu/g showed distinct superparamagnetic characteristics and the magnetic microspheres with a size of 10 μm were relatively uniform.