Narrow Results

A simple wet-explosion method was employed to synthesize the Ni–Bi–P composite microspheres. The hollow structure was obtained possibly due to the violent evolution of gas bubbles when the reaction reagents were mixed. The hollow microspheres of Ni–Bi–P exhibited outstanding high catalytic activity for the reduction of $p$-nitrophenol ($p$-NP) to form $p$-aminophenol in the presence of NaBH₄ within only 1s. Due to the space limitation, the hollow structure of Ni–Bi–P microspheres helps to accommodate and confine the molecules of NaBH₄ and $p$-NP within the small space where NaBH₄ and $p$-NP contact closely at Ni–Bi–P catalysts. The synergetic action of Ni, Bi and P elements also contributes the enhanced catalytic activity.

Novel Multiplex PCR Technologies.

Reducing the Spread of TB in China: New Technology Needed to Turn the Tide.

Application of Rapid and Accurate Two-Stage Genotyping Strategy in MRSA Nosocomial Infection in Japan.

Introduction to Luminex^®xMAP^® Technology and Applications for Biological Analysis in China.

Label-free Real-time Cell Based Assay System for Evaluating H1N1 Vaccination Success.

A novel sonochemical method is developed to coat multi-walled carbon nanotubes (MWCNTs) on expandable thermoplastic (acrylonitrile and methylacrylonitrile polymer) microspheres (Expancel). These polymeric thermoplastic microspheres were further fabricated in a form of foam panels using a compression molding technique. The test coupons were cut precisely from the as-prepared panels and characterized by scanning electron microscopy (SEM), X-ray diffraction, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The SEM studies have shown that the MWCNTs are well dispersed over the entire volume of the matrix with minimal agglomeration. The foam cell structures are well-ordered, spherical in shape, and uniform in size. The TGA and DSC analyses indicate that the nanocomposite foam samples are thermally more stable than the corresponding neat foam samples. The compression tests have been carried out for both nanocomposite and neat foam samples. These test results show a significant increase in compressive strength and modulus for nanocomposite foam samples as compared to the neat foam samples. These enhancements in compressive properties have been observed repeatedly for multiple batches. The details of synthesis procedure, thermal and mechanical characterization are presented in this paper.

The Fe₃O₄@C core/shell microspheres were fabricated via a two-step process. Fe₃O₄ microspheres were firstly prepared, and Fe₃O₄@C core/shell microspheres were subsequently fabricated using glucose as a carbon source by a hydrothermal route, in which the thickness of the carbon coating was about 20 nm. The resulting products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR). The Nitrogen adsorption–desorption isotherms reveal their mesoporous structure and larger BET surface area (62.3 m²g^-1). The Fe₃O₄@C core/shell microspheres possess ferromagnetism and high saturation magnetization (39.2 emu ⋅ g^-1). Bovine hemoglobin (BHb) was used as a model protein to test the adsorption and desorption properties of the Fe₃O₄@C core/shell microspheres. The capacity for BHb adsorption was more than 71.3 mg/g. According to the values obtained in the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay the Fe₃O₄@C core/shell microspheres show a low toxicity. Therefore, the prepared Fe₃O₄@C core/shell microspheres are of great significance for guided site-specific drug delivery.

In this paper, a new simple approach has been developed for the preparation of α-Fe₂O₃ microspheres by a facile hydrothermal method using PVP as a surfactant. Uniform α-Fe₂O₃ microspheres could be routinely synthesized through solvothermal approach by controlling the PVP/FeCl₃⋅6H₂O ratio. The as-obtained α-Fe₂O₃ microspheres exhibit high efficiency on the decolorization of RhB aqueous solution in the presence of H₂O₂ at room temperature.

Nearly monodisperse CaWO₄ and CaWO₄:Eu³⁺ microspheres have been synthesized in large scale by a surfactant-assisted solution route, in which cetyltrimethyl ammonium bromide (CTAB) is used. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) were used to characterize the resulting samples. The results of XRD indicate that the CaWO₄ and CaWO₄:Eu³⁺ samples have the scheelite structures. The growth process of these nearly monodisperse spheres with an average diameter around 3.2 μm has been examined. The results of FTIR indicate that CTAB plays an important role in the formation of microspheres. The CaWO₄ microspheres exhibit a blue emission band with a maximum at 423 nm. But the CaWO₄:Eu³⁺ microspheres exhibit a red emission band with a maximum at 623 nm.

Novel hierarchical porous NiMoS₄ microspheres with high electrochemical performance was successfully prepared using a facile one-step hydrothermal method. The dual application of porous NiMoS₄ microspheres in energy harvesting and storage (i.e., dye-sensitized solar cells (DSSCs) and supercapacitors (SCs), respectively) is explored. In contrast to NiS₂ nanosheets, MoS₂ nanosheets and Pt counter electrodes (CEs), the NiMoS₄ microspheres CE demonstrated the lowest charge transfer resistance and highest electrocatalytic activity for the I${}_3^{-}$/I⁻ redox couple reaction. The NiMoS₄-based DSSC showed a higher power conversion efficiency (8.9%) even than that of Pt-based DSSC (8.7%) under simulated standard global AM 1.5G sunlight (100mWcm${}^{-2}$). As an electroactive material for SCs, the assembled NiMoS₄//AC asymmetric supercapacitor showed excellent specific capacitance (118.7Fg${}^{-1}$ at 1A${\mathrm{\text{g}}}^{-1})$, high energy density of 42.2Whkg${}^{-1}$ (with a power density of 799.2Wkg${}^{-1})$, and superior cycling durability with a specific capacitance retention of 79.5% after 9000 cycles at 3Ag${}^{-1}$.

Silver-coated Ti₂Nb${}_{10}$O${}_{29}$ composite microspheres were successfully prepared by a solvothermal method with a subsequent post-annealing treatment. Effect of the coating Ag nanoparticles on the electrochemical properties was extensively studied. The XRD pattern shows that high purity Ti₂Nb${}_{10}$O${}_{29}$ was formed and no impurity phases are observed. Moreover, SEM, XPS and EDX clearly revealed that Ag nanoparticles were combined on the surface area of formed Ti₂Nb${}_{10}$O${}_{29}$ microspheres. The electrochemical performance of the Ag/Ti₂Nb${}_{10}$O${}_{29}$ composite microspheres was characterized via cyclic voltammograms (CV) measurements. The CV curves indicate that the coating Ag nanoparticles minimize the polarization of pristine Ti₂Nb${}_{10}$O${}_{29}$. The EIS indicates that the excellent rate capability of Ag/Ti₂Nb${}_{10}$O${}_{29}$ composite microspheres can be ascribed to the improved electronic conductivity due to the incorporation of Ag nanoparticles.

The hydrothermal method, using the template is a conspicuous way to change the morphology of the product, so it is used widely in many reports. The effect of temperature on morphology of NiCo₂S₄ by hydrothermal synthesis and its electrochemical properties is distinct as high-performance electrode materials for supercapacitors. With the help of the template (carbon sphere), different morphologies of NiCo₂S₄ under 90${}^{\circ }$C, 120${}^{\circ }$C and 180${}^{\circ }$C were obtained. They have different properties after electrochemical analysis. In order to build a hierarchical multi-level structure, two-step vulcanization was carried out at each temperature, resulting in the difference in the morphology and performance of the six sample of electrodes. The obtained NiCo₂S₄ electrodes exhibit 1000Fg${}^{-1}$ at the current density of 1Ag${}^{-1}$ in the second-step of the hydrothermal process under 120${}^{\circ }$C, which is superior to the microblocks NiCo₂S₄ electrode (90${}^{\circ }$C, 888Fg${}^{-1}$ at the current density of 1Ag${}^{-1}$) and microparticles NiCo₂S₄ electrode (180${}^{\circ }$C, 574Fg${}^{-1}$ at the same current density) in the second-step hydrothermal, which shows a high-rate capability (640Fg${}^{-1}$ at 20Ag${}^{-1}$). The obtained nanoparticles NiCo₂S₄ under 180${}^{\circ }$C in the first-step hydrothermal electrode had an excellent cycle retention rate (89.7%), although its specific capacitance was lower. At the same time, the specific capacitance of these sample electrodes obtained in the second-step hydrothermal process is superior to those from the first-step. It was mainly attributed to the fact that temperature can influence the morphology by controlling ion exchange. And our experiment aims to use the hydrothermal method and the template method to find a more suitable temperature range to provide more ideas.

The Ni-metal-organic frameworks microspheres (Ni-BTC) were prepared and used directly to construct non-enzymatic glucose sensors. The Ni-BTC sensors displayed much higher glucose sensing performance than that of Ni-MOFs derived NiO, which showed wide detection regions of 5–3000$\mu$M and 3500–6000$\mu$M with the sensitivity of 932.68$\mu$A$\cdot$mM${}^{-1}\cdot$cm${}^{-2}$ and 273.04$\mu$A$\cdot$mM${}^{-1}\cdot$cm${}^{-2}$, respectively. Moreover, it also displayed good selectivity and favorable sensing feasibility for serum analysis. The high performance of the non-enzymatic glucose detection on Ni-BTC may be due to the highly efficient charge transfers during the electrocatalytic glucose oxidation process.

Two kinds of chitosan/β-TCP microspheres were prepared; one was by a traditional emulsion technique (Group A), and the other was by a high-voltage electrostatic system (Group B). Both of the microspheres exhibited good sphericity and the β-TCP fine particles were well trapped inside the chitosan based particles. After 60-day shaking, Group A and Group B degraded by about 40% and 80% of initial weight, respectively. Two models of bone defects were created in rabbits included for a series of randomized blind pilot study. In the cranial model, two equal 10 mm diameter cranial defects were created. In condyle model, two equal 5 mm femur condyle defects were created on each hind leg, and underwent the same grafting treatment. After 4 weeks of implantation, both the cranial and condyle sites filled with Group A were shown to be surrounded by fibrous tissues with the presence of osteoblasts. In Group B, only condyle site showed the presence of osteoblasts. In contrast, fibrous tissue formation was seen on the control group after 4 weeks of healing. After 8 weeks of implantation, the condyle sites filled with Group A and Group B showed the presence of new bone formation as compared to control group. However, there was no obvious new bone formations in the cranial sites filled with both Group A and Group B. The same events were observed in the cranial sites after 12 weeks of implantation. In contrast, new bone formation was seen on the condyle sites in all three groups after 12 weeks of implantation.

Developments on tissue engineering, especially on tissue regeneration and drug delivery, demand also developments on biomaterials. Research on the preparation methods of biomaterials has exhibited remarkable advances in the recent years. Natural biomaterials, such as chitosan and collagen, or synthetic materials like poly(lactic acid) can be shaped in various forms. The parameters involved in the fabrication processes provide methodologies for control of the materials' properties, such as morphology, biodegradability, mechanical strength, and adhesion. As new applications develop for these materials, the preparation methods have to be optimized to achieve the desired material properties. These properties mostly not only mimic the conditions in the human body, but also may divert the microenvironment of cells in the diseased area in order to promote faster or guided healing and tissue regeneration. This review pays attention on some of the fabrication methods for biomaterial particulates of sizes in the micro- and nanoscale. The views expressed here focus on the many years of experience of the authors with electrostatic and ultrasonic fabrication methods. These methods are still under development and up to now can produce particulates of various sizes down to the nanometer scale with narrow size distributions. Such biomaterials that have extraordinary properties may provide ways for the development of remarkable biomedical applications.

Chitosan is a natural polysaccharide with great potential for biomedical applications due to its biocompatibility, biodegradable capability, and nontoxicity. Various techniques used for preparing chitosan microspheres/membranes and evaluations of these fabrications have also been reviewed. The hydrophilicity of chitosan provides unique characteristics of hydrogel formation with the acidic media and may entrap the drug content inside of the matrix for controlled release. In order to improve upon the scope of preparation of chitosan microspheres, we had successfully employed and incorporated a high-voltage system into the direct pumping injection process. The wide range of drug release profiles could be attributed to the surface characteristics, porosities, and various structures of chitosan microspheres upon treatment with Na₅P₃O₁₀/NaOH solutions of various volume ratios. We also demonstrated that with the addition of chitosan/β-TCP microspheres as a constituent into the PMMA cement significantly decreases the curing peak temperature and increases the setting time. The excellent gelforming property of chitosan offers another biomedical application in membrane separation fields. Chitosan membranes were prepared by a thermal induced phase separation method, following treatment with nontoxic NaOH gelating and Na₅P₃O₁₀, Na₂SO₃ crosslinking agents. In order to further improve the mechanical strength and biocompatibility and to expand the potential of chitosan GTR membranes in periodontal applications, various chitosan membranes incorporating with negatively charged alginate, bioactive tricalcium phosphate, and platelet rich plasma, respectively, were also prepared and characterized. Moreover, we had also utilized chitosan, which with good blood-clotting, cheap, and easy preparation characteristics, as the raw material to prepare rapid clotting wound dressing and tooth plug.

This study evaluates the properties of Tramadol-HCl-loaded polyoxalate (TH-loaded POX) microspheres prepared by oil-in-oil (O₁/O₂) emulsion solvent evaporation method, specifically designed for sustained drug release. Morphology and physicochemical characteristics of the as-fabricated were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR) spectroscopy, while the encapsulation efficiency and release profile of drug (Tramadol-HCl, TH) from POX microspheres were assessed by high-performance liquid chromatography (HPLC). The influence of reaction temperature, stirring speed, initial drug ratio, molecular weight (M_w) and concentration of polyoxalate (POX) on the fabrication of TH-loaded POX microspheres were investigated. Results showed that the characteristics of the microspheres and drug-loaded content can be optimized by adjusting the parameters of preparation conditions. Also, the degradation behavior of TH-loaded POX microspheres was evaluated from in vitro test for 2 weeks. Overall, the results showed that POX microsphere can be one of the promising polymers for controlled injection release formulation with site-specific drug release capabilities.

The fate processes and cellular behavior of stem cells are highly influenced by the microenvironment, termed as microniche. Based on the stem cell source and its potency, it can be differentiated into various cell types and thereby explored for therapeutic application. Recent advances in stem cell research have shown promise in tissue engineering (TE) and regenerative medicine. Moreover, research on biomaterials has progressed from simple scaffolding fabrications to biomimetic complex constructs. The integration of biocompatible, biodegradable biomaterials with stem cells has been explored as a viable choice for enhancing the efficiency of cell grafting as well as promoting specific cell differentiation. Surface functionalization of scaffolds, biofabrication of hydrogels, composite scaffolds and microspheres/microbeads have been designed with biomimetic characteristics for specific tissue requirements. This chapter throws light on the various biomaterial-based systems that serve as stem cell delivery modalities and provide favorable cellular microenvironments for tissue regeneration.

Self catalysed and latent acid poly(ortho esters) (POEs) with different compositions were used to fabricate the microspheres using a W/O/W double emulsion solvent extraction/evaporation method. The characteristics of POEs microspheres were analyzed by size distribution, surface morphology, protein encapsulation efficiency, initial burst and release profile. The results showed that protein-containing microspheres fabricated with different compositions of POEs had different release profiles. For instance, compared with the microspheres of POE prepared from 3, 9-diethylidene – 2, 4, 8, 10 – tetraoxaspiro [5, 5] undecane, a 89/10/1 mixture of cyclohexanedimethanol (CDM), triethyleneglycol (TEG) and cyclohexanedimethanol – monolactate (CDM-mLT) (POE4), the microspheres of POE prepared from a 75/20/5 mixture of CDM, TEG and CDM-mLT (POE3) has a more rapid release rate. It is due to this fact that TEG is more hydrophilic, compared with CDM. So a higher concentration of TEG dimer segments in the POE3 backbone can result in a faster water penetration rate. As a consequence, the degradation rate of POE3 is faster than that of POE4. However, the segments of hexanediol-diglycolate (HD-diGL) are more hydrophilic than CDM-mLT. So the release rate of the microspheres of POE prepared from 3, 9-diethylidene – 2, 4, 8, 10 – tetraoxaspiro [5, 5] undecane, a 75/20/5 mixture of CDM, TEG and HD-diGL (POE2) is faster than that of POE3. Moreover, POE microspheres at 37°C has a higher release rate than at 22°C. The SEM images of POE microspheres showed that all the POE microspheres have smooth and non-pores surface morphology, resulting in a low initial release. We suggest that poly (orthoesters) can be utilized for microencapsulation of active agents such as protein drugs. By using POEs with various compositions, release profiles of protein drug and the polymer degradation rate can be controlled.

Hydroxyapatite porous microspheres were fabricated by multiple emulsion. XRD and FTIR reveal that the as-obtained samples consisted of hydroxyapatite. TEM and SEM showed that the as-prepared products were composed of porous microspheres assembled with nanorods and had three-dimensional nanoporous nanostructured networks. These nanoparticles aggregate to form porous with a pore size of 2.5-9.5nm among them. The formation mechanism of porous microspheres has been discussed.

Since the discovery of cisplatin, drugs based on platinum, have made a significant impact on the treatment of various cancers. The administration of platinum drugs is however accompanied by significant side effects. This chapter discusses the types of drug delivery systems that have been developed in order to enable the targeted delivery while maintaining controlled temporal supply of the drug. The sizes of carriers range from nanometer to micrometer sized particles. The most common types of drug carriers are micelles, liposomes, nanoparticles, and dendrimers, but also a few microspheres have been developed. Most striking aspect of the delivery of platinum drugs is the possibility of physical encapsulation but also the binding of the drug to the polymer carrier coordinate covalent bond. Since platinum drugs have typically two permanent and two leaving ligands, the polymer can be part of either ligand. As the leaving ligand, the platinum drug is released often as cisplatin. If the polymer provides the functionality for the permanent ligand, a new macromolecular drug has been formed. In addition to the attachment of pt(II) drugs, recent offorts are devoted to the conjugation via the Pt((IV) prodrug.

Uniform and well-dispersed SrMoO₄ hierarchical microspheres have been synthesized via a facile citrate-assisted hydrothermal approach. XRD results demonstrate that Ln³⁺-doped samples can be well indexed to the pure tetragonal scheelite-type SrMoO₄, indicating that the Eu³⁺, Tb³⁺, Dy³⁺, and Sm³⁺ have been effectively doped into the SrMoO₄ host lattices. SEM and TEM images indicate that the as-obtained SrMoO₄ microspheres consist of tiny packed nanocrystallites. The as-synthesized SrMoO₄:Ln³⁺ (Ln = Eu, Tb, Dy, and Sm) samples show intense characteristic emissions with different colors under ultraviolet excitation, which may find potential applications in the fields of fluorescent lamps, color displays, and light-emitting diodes (LEDs).