Fabrication and Properties of Gelatin/Chitosan Microspheres Loaded with 5-Fluorouracil

The use of microspheres as drug delivery vehicles for anticancer therapeutics has great potential to revolutionize the future of cancer therapy. The present paper describes the influence of process variables on the encapsulation and loading efficiency of 5-Fluorouracil (5-FU) in gelatin/chitosan (Gel/Cs) microspheres. The influences of preparation parameters, including the contents of the emulsifier Span-80, the cross-linking agent and 5-FU, and the stirring speed, on drug loading and encapsulation efficiency of the microspheres were investigated. The experimental results indicated that drug loading and encapsulation efficiency of microspheres increased with increasing concentration of the cross-linking agent; and then decreased when the concentration of the cross-linking agent was higher than 0.3 ml·g^?1 of Gel/Cs. Drug loading and encapsulation efficiency increased with increasing concentration of Span-80; they reached the maximum value when the concentration of the emulsifier was 0.012 g·ml^?1. The loading and encapsulation efficiency of the microspheres also increased with increasing stirring speed. In addition, drug loading and encapsulation efficiency increased with increasing concentration of 5-FU; however, the encapsulation efficiency decreased when the concentration of 5-FU was higher than 40 mg·ml^?1.     

Synthesis of an Organic–Inorganic Hybrid Polymeric Material and Its Adsorption Performance Characterization Toward Acrylamide

An organic–inorganic hybrid functionalized material was successfully synthesized by a surface molecular imprinting technique combined with a nonhydrolytic sol–gel process using acrylamide as the template, methacrylic acid as the functional monomer, methacryloxypropyltrimethoxysilane as the cross-linker, and magnetic chitosan microspheres as the support material. The adsorption ability and selectivity of this material toward acrylamide was characterized. Experimental results showed that the imprinted polymer exhibited better recognition and selective performance toward acrylamide than the nonimprinted polymer. The saturated binding capacity (Q _max) was 104.68 mg/g, and the equilibrium dissociation constant was 263.16 mg/mL. This prepared material also offered fast kinetics for the adsorption and desorption of acrylamide. After shaking for 5 min, an adsorption capacity of 4.71 mg/g was obtained, and it almost reached the adsorption equilibrium within 90 min.     

Control of Size and Morphology of Gelatin Microspheres

Gelatin microspheres with different particle size and surface morphology were obtained through an emulsification-coacervation method in water-in-oil (W/O) emulsions. The effect of preparation parameters on the size and morphology of the gelatin microspheres was investigated, and the influence of post-treatment, including washing solvent and freeze-drying, on the surface morphology was also studied. The results showed that spherical microspheres, without aggregation phenomena and with a very smooth and uniform surface, are formed during the cross-linking process. The particle size of the gelatin microspheres increased with increasing concentration of the gelatin solution, emulsifying time, and W/O phase volume ratio; however, the particle size of the gelatin microspheres decreased with increasing concentration of the emulsifier and stirring rate. During the post-treatment process, the surface of the gelatin microspheres collapsed when dehydrated by acetone; the surface morphologies of microspheres were smoother when dehydrated by acetone/water solution with a volume ratio of 5:1 and acetone in sequence. When the obtained smooth gelatin microspheres were soaked in deionized water for 24 h and then treated by freeze-drying method for 12 h, microspheres with porous structure were obtained.     

Synthesis of an Organic-Inorganic Hybrid Polymeric Material and its Adsorption Performance Characterization Toward Acrylamide

An organic-inorganic hybrid functionalized material was successfully synthesized by a surface molecular imprinting technique combined with a nonhydrolytic sol-gel (NHSG) process using acrylamide (AA) as the template, methacrylic acid as the functional monomer, methacryloxypropyltrimethoxysilane as the cross-linker and magnetic chitosan (CTS) microspheres as the support material. The adsorption ability and selectivity of this material toward AA was characterized. Experimental results showed that the imprinted polymer exhibited better recognition and selective performance toward AA than the nonimprinted polymer (NIP). The saturated binding capacity (Q _max) was 104.68 mg/g, and the equilibrium dissociation constant was 263.16 mg/mL. This prepared material also offered fast kinetics for the adsorption and desorption of AA. After shaking for 5 min, an adsorption capacity of 4.71 mg/g was obtained, and it almost reached the adsorption equilibrium within 90 min.     

Preparation of an Estriol Surface Imprinted Polymer and its Adsorption Ability Evaluation

A novel molecularly imprinted polymer/magnetic chitosan microsphere (MIP/MCM) was prepared by a surface molecular imprinting technique in combination with a sol–gel process, using estriol as the template, γ-aminopropyltrimethoxysilane as the functional monomer, tetraethoxysilicane as the cross-linker, and magnetic chitosan as the support material. The adsorption ability and selectivity of the polymeric material toward estriol were evaluated. The results indicated that the prepared material had higher adsorption capacity and selectivity toward estriol than the non-imprinted polymer/MCM. The theoretical maximum adsorption capacity (Q _max) was 8.13 mg g^?1, and the equilibrium dissociation constant (K _d) was 625.0 mg mL^?1. The functionalized material had fast uptake kinetics, 83.64% of the saturated adsorption capacity was obtained within a period of 60 min, and the adsorption almost reached equilibrium within 90 min. This prepared material has potential to be used as a sorbent in solid-phase extraction (SPE) to enrich trace estriol in samples.     

Chitosan magnetic microspheres for technological applications: Preparation and characterization

One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800–1100 μm.The adsorption of Cu(II) onto chitosan–magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.     

Optimization of Release Conditions of Alzheimer's Drug Donepezil Hydrochloride from Sodium Alginate/Sodium Carboxymethyl Cellulose Blend Microspheres

Microspheres of blends of sodium alginate (NaAlg) and sodium carboxymethyl cellulose (NaCMC) were prepared by a water-in-oil (w/o) emulsion crosslinking method and used for the release of donepezil hydrochloride (DP), which is an Alzheimer's drug. The microspheres were characterized with Fourier transform infrared spectroscopy (FTIR), differantial scanning calorimetry (DSC), and scanning electron microscopy (SEM). The microsphere characteristics, including DP entrapment efficiency, particle size, equilibrium swelling degree (ESD), and DP release kinetics, were determined. The effects of the preparation conditions, including the NaAlg/NaCMC (w/w) ratio, drug/polymer (w/w) ratio, cross-linker concentration and time of exposure to the cross-linker, on the release of DP were investigated for successive gastrointestinal tract pH values of 1.2, 6.8, and 7.4 at 37°C. The release of DP increased with the increase in NaAlg/NaCMC (w/w) ratio and drug/polymer (d/p) ratio, while it decreased with increasing extent of cross-linking. The optimum DP release was obtained as 99.13% for a NaAlg/NaCMC (w/w) ratio of 2/1, d/p ratio of 1/4, CaCl₂ concentration of 5% and crosslinking time of 30 min. It was also observed from release results that DP release from the microspheres through the external medium was higher at low pH (1.2) values than that at high pH (6.8 and 7.4) values. The DP release of the microspheres followed either Fickian transport below a value of n < 0.5 or anomalous transport (n = 0.5–1.0).     

Effect of annealing temperature on optical and electrochemical properties of chitosan–ZnO nanostructure

Chitosan–ZnO nanostructures were prepared by chemical precipitation method using different concentration of zinc chloride and sodium hydroxide solutions. Nanorod-shaped grains with hexagonal structure for samples annealed at 300 °C and porous structure with amorphous morphology for samples annealed at 600 °C were revealed in SEM analysis. X-ray diffraction patterns confirmed the hexagonal phase ZnO with crystallite size found to be in the range of ~24.15–34.83 nm. Blue shift of UV–Vis absorption shows formation of nanocrystals/nanorods of ZnO with marginal increase in band gap. Photoluminescence spectra show that blue–green emission band at 380–580 nm. The chitosan–ZnO nanostructures used on surface of a glassy carbon electrode gives the oxidation peak potential at ~0.6 V. The electrical conductivity of chitosan–ZnO composites were observed at 2.1?×?10^?5 to 2.85?×?10^?5?S/m. The nanorods with high surface area and nontoxicity nature of chitosan–ZnO nanostructures observed in samples annealed at 300 °C were suitable as a potential material for biosensing.     

Template-free sonochemical synthesis of hierarchically porous NiO microsphere

A novel template-free sonochemical synthesis technique was used to prepare NiO microspheres combined with calcination of NiO_2.45C_0.74N_0.25H_2.90 precursor at 500 °C. The NiO microspheres samples were systematically investigated by the thermograviometric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier-transformed infrared spectroscopy (FT-IR), Brunnauer–Emmett–Teller (BET) nitrogen adsorption–desorption isotherms, laser particle size analyzer, and ultraviolet–visible spectroscopy (UV–Vis). The morphology of the precursor was retained even after the calcination process, and exhibited hierarchically porous sphericity. The morphology changed over the ultrasonic radiation time, and the shortest reaction time was 70 min, which was much less than 4 h for the mechanical stirring process. The mechanical stirring was difficult to form the complete hierarchically porous microsphere structure. The BET specific surface area and the median diameter of the hierarchically porous NiO microspheres were 103.20 m²/g and 3.436 μm, respectively. The synthesized NiO microspheres were mesoporous materials with a high fraction of macropores. The pores were resulted from the intergranular accumulation. The ultraviolet absorption spectrum showed a broad emission at the center of 475 nm, and the band gap energy was estimated to be 3.63 eV.     

Preparation and Characterization of Chitosan-Gelatin/Glutaraldehyde Scaffolds

Chitosan-gelatin (CG) scaffolds were fabricated with glutaraldehyde as a cross-linker by vacuum freeze-drying. Mixtures of different volumes of chitosan and glutaraldehyde were considered. Morphology, porosity, density, and water absorbency of the scaffolds were studied. Both tensile and compressive properties of the scaffolds were tested. In addition, cellular adherence, proliferation, and morphology on the scaffolds were tested to evaluate the compatibility. It was found that porosity, density, water absorbency, and mechanical properties of CG scaffolds changed with the variation of chitosan or GA content. The adequate adherence, proliferation, and morphology of HaCaT type cells on the scaffolds showed that these scaffolds can be used as carriers for culturing HaCaT. The CG scaffolds, particularly those with chitosan-gelatin volume ratios of 1:1 and adding 6% or 8% volume of 0.25 wt% GA solution, were more suitable than the others through comparing the above properties and could be promising candidates for engineering skin tissue.     

Carbon@SnS<Subscript>2</Subscript> core-shell microspheres for lithium-ion battery anode materials

A novel unique C@SnS₂ core-shell structure composites consisting of well-dispersity carbon microspheres and ultrathin tin disulfide nanosheets were successfully synthesized for the first time through a simple solvothermal method. The thin SnS₂ nanosheets grew onto the carbon microspheres surfaces perpendicularly and formed the close-knit porous structure. When it was used as anode materials for lithium-ion batteries, the hybrid C@SnS₂ core-shell structure composites showed a remarkable electrochemical property than pure SnS₂ nanosheets. Typically, the hybrid composites with SnS₂ nanosheet shells and carbon microsphere’s core exhibited an excellent initial discharge capacity of 1611.6 mAh/g. Moreover, the hybrid composites exhibited capacities of 474.8–691.6 mAh/g at 100 mA/g over 50 battery cycles, while the pure SnS₂ could deliver capacities of 243–517.6 mAh/g in the tests. The results indicated that the improvement of lithium storage performance of the core-shell structure C@SnS₂ anode materials in terms of rate capability and cycling reversibility owing to the introduction of the smooth carbon microspheres and special designing of core-shell structure.     

Optimization of Fluoroimmunoassay against C-Reactive Protein Exploiting Immobilized-antigen Glass Slide

An optimization experiment for an indirect-competitive (IC) fluoroimmunoassay (FIA) against C-reactive protein (CRP) was conducted exploiting an immobilized-antigen glass slide and an anti-CRP antibody tagged with fluorescent silica nanoparticles (FSNPs). The optimized conditions for the IC FIA were as follows: time and concentration of treatment with glutaraldehyde, 30 min and 1.5 %, respectively; time of reaction with coating antigen and concentration of coating antigen for immobilization, 1 h and 0.1 mg/mL, respectively; concentration of FSNP-anti-CRP antibody conjugate coupled by the biotin-avidin interaction, the bioconjugate, for immune reaction, 0.250 mg/mL; concentration of bovine serum albumin (BSA) for blocking and time of blocking with BSA, 3 % and 30 min, respectively. By using the glass slide, a highly sensitive detection against CRP was possible with the limit of detection below 0.1 ng/mL.     

臭氧改性及搅拌桨结构对大直径双层球制备的影响

随着高功率激光器的飞速发展,ICF物理实验对聚苯乙烯（PS）-聚乙烯醇（PVA）双层空心微球的规格要求逐渐提高,直径要求将达到700～900 m。针对该直径范围的PS-PVA双层空心微球,通过采用PS球臭氧化表面改性技术和搅拌桨叶轮结构优化技术,对传统乳液微封装法制备双层空心微球工艺进行了改进,臭氧化表面改性后PS固体核心发生憎水-亲水转变,提高了PS与PVA之间的作用强度;搅拌桨叶轮结构优化,改善了体系容器内溶液流场均匀性,使得微球在整个体系中的运动相对平稳,从而初步制得了直径范围在700～900 m的双层空心微球。     

壳聚糖絮凝澄清蛇足石杉提取液的工艺研究

采用正交试验设计法考察了壳聚糖对蛇足石杉提取液的絮凝澄清效果。优选出的最佳工艺条件为:料液比(g/mL)为1:10,pH为5,反应温度50℃,壳聚糖浓度0.5g/L,反应时间60min,搅拌速度100r/min。在此条件下透光率可达81.6%。壳聚糖用于蛇足石杉提取液的絮凝澄清切实可行,并为后续的工艺改进提供了科学依据。     

Preparation of Poly (L-lactic Acid) Microsphere

Poly (L-lactic acid) (PLLA) microspheres were prepared by a solvent evaporation method based on an oil/water emulsion. The effect of the mass ratio of PLLA and poly(vinyl alcohol) (PVA) on the formation of the microspheres was discussed, and the influence of extraction speed of dichloromethane on the microsphere morphology was also studied. Moreover, the influences of the PLLA concentration and the volume ratio of water phase to dichloromethane phase were investigated. The results showed that stable microspheres can be obtained under the conditions that the mass ratio of PLLA to PVA is 20:1. Porous microspheres were obtained under faster evaporating speed of dichloromethane. The microsphere size increased with increasing PLLA concentration. The microsphere size also increased with the increase of the volume ratio of water phase to dichloromethane phase.     

Characterization of Poly(Vinyl Alcohol) Membranes Cross-Linked by Aldehyde-Substituting Cyclotriphosphazene

A new type of cross-linker, based on cyclotriphosphazene with six aldehyde groups, was used for the cross-linking of poly(vinyl alcohol) membranes. FTIR-ATR analysis indicated that cyclophosphazene reacted with poly(vinyl alcohol) by forming C–O–C bonds. TGA and DTG analysis showed that cross-linking improved the thermal stability. The swelling degree and pervaporation properties of cross-linked PVA membranes were also characterized. With increasing cross-linker concentration, swelling degrees and flux decrease while separation factors increase. Compared with PVA membranes cross-linked by glutaraldehyde, PVA membranes cross-linked by cyclophosphazene exhibited better selectivity and permeation rate.     

Application of mesoporous carbon and modified mesoporous carbon for treatment of DMF sewage

Mesoporous carbon (MC) was prepared in soft template, and potassium ferricyanide was added into MC to prepare the modified mesoporous carbon (MMC). TEM, SEM, FT-IR, and N₂ adsorption–desorption were used to characterize the textural properties of mesoporous materials. The BET specific surface area, pore volume, and the pore size of MC and MMC were 607.6321 and 304.7475 m²/g, 0.313552 and 0.603573 cm³/g, and 5.4356 and 7.9227 nm, respectively. The adsorption capabilities of MC and MMC were compared with the silica mesoporous material MCM-41. The influences of different adsorption conditions were optimized. For MC, the optimums of adsorbent dose, DMF initial concentration, rotating speed, and pH were 0.002 mg/50 mL, 200 mg/L, 200 r/min, and 4, respectively. MMC showed the highest DMF adsorption capacity at adsorbent dose 0.002 g/50 mL, DMF initial concentration 1000 mg/L, rotating speed 1000 r/min, pH more than 9, and contact time of less than 20 min. Meanwhile for MC, MMC, Pseudo-second-order equation was used to fit adsorption kinetics data. And adsorption process could be well fitted by Langmuir and Freundlich adsorption isotherms of MC, MMC. The results showed that MMC was a perfect adsorbent for DMF, and it was easy to separation and recycle. The recycling property of MMC was still relatively better than other two adsorbents.     

A novel polysiloxane-based polymer as a gel agent for gel–VRLA batteries

In this study, a novel polysiloxane-based gel agent (PSGA) was synthesized by using poly(dimethylsiloxane-co-alkylmethylsiloxane) and used as a gel agent for gel–valve-regulated lead–acid batteries. A PSGA was characterized by Fourier transform infrared, zeta meter, scanning electron microscopy, and energy-dispersive X-ray analysis. The electrochemical characterization of the gel system for the optimization of some parameters, such as concentration of gel agent, stirring rate, and agitation time, was conducted by cyclic voltammetric and electrochemical impedance spectroscopic analyses. The optimum concentration of the gel agent was determined as 6 wt% of the PSGA to form the best gel structure. The mechanical parameters related to the formation of a suitable gel structure were also investigated. The optimum stirring rate and agitation time were determined as 500 rpm and 2.5 h, respectively. The charge–discharge tests were applied to the gel system, and the highest capacity was determined in the PSGA-based gel system as 10 mAh at the end of the 100th cycle. The capacity of non-gelled system was the lowest.     

Properties of Absorbent Acrylic Foam Prepared Based on the Method of High Internal Phase Emulsion

Acrylate and methacrylate monomers absorbent acrylate foams were prepared based on the method of high internal phase emulsion (HIPE). The influence of reaction conditions on liquid absorption by acrylate foams was studied. The reaction conditions included monomer ratio, cross-linker amount, initiator amount, emulsifier amount, emulsion concentration, emulsification temperature, and the curing time. The reaction conditions were determined to achieve the best liquid absorption by acrylate foams. Acrylate foams were analyzed with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that when the monomer ratio was 9:1, cross-linking agent was 30% of monomer amount, initiator amount was 4% of the reactants amount, emulsifier amount was 8% of the reactants amount, the ratio of aqueous phase to oil phase was 32:1, emulsification temperature was 75°C, and curing time was 1.5 h, we could prepare the acrylate foam material with the best liquid absorption. Reaction of monomer and cross-linking agent was confirmed by FTIR analysis. The pore sizes of acrylate foam were between 1 μm and 8 μm according to SEM analysis. This material was very suitable to absorb aqueous fluids.     

组装条件对涂布法制备SiO2结构色涂层光谱性质影响研究

为了实现结构色涂层在纸张表面的快速制备，研究不同组装条件对SiO₂结构色涂层呈色效果的影响，采用快速涂布的方法，在纸张表面制备出了大面积且具有随角异色特性的结构色涂层。探讨SiO₂微球粒径、分散液浓度及涂布次数等因素对结构色涂层光学特性的影响，通过优化自组装条件和分析周期性结构构筑类型，阐明快速涂布法构建的SiO₂微球在激光打标纸上的自组装过程及结构色呈色机理。应用数码相机、3D激光共聚焦形貌测量显微镜等仪器对样品的颜色外观和微观结构进行测量，表征样品的呈色性能及表面结构。使用X-Rite MA68Ⅱ多角度分光光度仪及光纤光谱仪测量反射光谱，进而用CIEL*a*b*色度值对制备的结构色涂层的光学性能进行分析。结果表明，通过快速涂布自组装法制备所得的结构色涂层，SiO₂微球粒径尺度对样品色调影响显著，随着微球粒径的增加，反射光谱中心波长发生红移，且该涂层有角度依赖特性，当固定入射角度为45°时，随着探测方向与镜面反射方向夹角的增大，中心波长发生红移；微球溶液的浓度可以调控结构色涂层反射光谱曲线的半高宽及反射率峰值，进而影响样品的亮度和彩度，而对于光子带隙的位置无明显影响。微球浓度为4%时，样品表面呈现出基材本身的黑色，微球浓度为8%时，200，220和250 nm粒径的样品表面分别可以呈现彩度较低的蓝色、绿色、黄色，微球浓度增加到10%时，纸张表面的结构色涂层彩度提高，色调不变；随着涂布次数的增加，反射光谱曲线的半高宽变窄，且反射峰位发生蓝移，涂布次数达到3次时，反射峰位最接近于根据布拉格定律计算出的理论值，但涂布次数的增加也使得结构色涂层表面产生白色的不均匀现象。