Neurite outgrowths of neurons using neurotrophin-coated nanoscale magnetic beads

Neurotrophin-coated nanoscale magnetic beads were used to regulate the differentiation and survival of neurons. The beads coated with nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF) promoted neurite outgrowths of neurons in the same manner as soluble NGF or soluble BDNF, but beads coated with bovine serum albumin did not promote neurite outgrowths. When the volume of NGF-coated bead solution was increased, the number of neurons with neurite outgrowths increased. The addition of anti-NGF antibodies decreased the numbers of neurons with neurite outgrowths in proportion to the volume of anti-NGF antibodies added. NGF-coated beads appeared to bind to soma with neurite outgrowths as determined using fluorescence. In addition, hybrid beads coated with both NGF and BDNF promoted neurite outgrowths of PC12h cells, although the cells did not produce neurite outgrowths in response to BDNF. Neurons with neurite outgrowths could be concentrated within a particular area when NGF-coated beads were immobilized in a particular area of the culture plate surface using a magnet. The results demonstrate that neurotrophin-coated nanoscale magnetic beads allow us to cultivate neurons in a selected area of the culture plate surface by using a magnet. Thus, neurotrophin-coated nanoscale magnetic beads are applicable to micro-integrated systems and biosensors.     

Uranyl-sorption properties of amorphous and crystalline TiO₂/ZrO₂ millimeter-sized hierarchically porous beads

Hierarchically porous TiO(2)/ZrO(2) millimeter-sized beads were synthesized using a sol-gel templating technique, and investigated for suitability as radionuclide sorbents using uranyl as a radionuclide-representative probe. The bead properties were varied by altering either composition (22, 36, and 82 wt % Zr in the Ti/Zr composite) or calcination temperature (500 or 700 °C). Uranyl adsorption was higher for the crystalline beads (surface area: 52-59 m(2) g(-1)) than the amorphous beads (surface area: 95-247 m(2) g(-1)), reaching a maximum of 0.170 mmol g(-1) for the 22 wt % Zr sample. This was attributed to the higher surface hydroxyl density (OH nm(-2)), presence of limited microporosity, and larger mesopores in the crystalline beads. Mass transport properties of the crystalline beads were not compromised by the large bead diameter: sorption rates comparable to those reported for powders were achieved and rates were higher than exclusively mesoporous reported systems, thereby highlighting the importance of pore hierarchy in designing materials with improved kinetics. Chemical stability of the sorbent, an important property for processes involving corrosive effluents (e.g., radioactive waste), was also assessed. Crystalline beads displayed superior resistance against matrix leaching in HNO(3). Stability varied with composition: the 22 wt % Zr sample demonstrated the highest stability.     

Efficient removal of heavy metal ions with biopolymer template synthesized mesoporous titania beads of hundreds of micrometers size

We demonstrated that mesoporous titania beads of uniform size (about 450 μm) and high surface area could be synthesized via an alginate biopolymer template method. These mesoporous titania beads could efficiently remove Cr(VI), Cd(II), Cr(III), Cu(II), and Co(II) ions from simulated wastewater with a facile subsequent solid-liquid separation because of their large sizes. We chose Cr(VI) removal as the case study and found that each gram of these titania beads could remove 6.7 mg of Cr(VI) from simulated wastewater containing 8.0 mg·L(-1) of Cr(VI) at pH = 2.0. The Cr(VI) removal process was found to obey the Langmuir adsorption model and its kinetics followed pseudo-second-order rate equation. The Cr(VI) removal mechanism of titania beads might be attributed to the electrostatic adsorption of Cr(VI) ions in the form of negatively charged HCrO(4)(-) by positively charged TiO(2) beads, accompanying partial reduction of Cr(VI) to Cr(III) by the reductive surface hydroxyl groups on the titania beads. The used titania beads could be recovered with 0.1 mol·L(-1) of NaOH solution. This study provides a promising micro/nanostructured adsorbent with easy solid-liquid separation property for heavy metal ions removal.     

Encapsulation of β-carotene from sea buckthorn (Hippophaë rhamnoides L.) juice in furcellaran beads

The objective of this study was to prepare and evaluate furcellaran beads as an encapsulation material for β-carotene from sea buckthorn (Hippophaë rhamnoides L.) juice. Beads were prepared by ionotropic gelation. The influence of bead formulation factors on the particle size and firmness was investigated and the encapsulation efficiency of β-carotene in beads was studied. The nature of the cation, the polymer and cation concentration, and the proportion of volumes of the outer to the inner phase influenced the size and firmness of furcellaran beads. With increasing proportion of sea buckthorn juice in the formulae, firmness of furcellaran beads decreased. The encapsulation efficiency of β-carotene from sea buckthorn juice in furcellaran capsules was 97%. It suggested that furcellaran beads may be applied for β-carotene encapsulation.Industrial relevanceEncapsulation is a rapidly emerging area with multitude of applications in biotechnology, one of them being the controlled release of active biomolecules. The sensitivity to the environmental factors makes furcellaran a promising material for the controlled release of pharmaceuticals, (pro)biotica, and bioactive materials. Entrapment of these materials into the furcellaran beads by protecting them against degradation processes could solve the problem to incorporate health promoting ingredients into food without reducing their bioavailability or functionality. The change of pH in the digestive system could cause degradation of the beads followed by release of bioactive materials in the organism. It does create a basis for new product development in food industry. However, more work regarding to the improvements of bead stability and the release of entrapped materials are required.     

果胶/聚间苯二胺凝胶珠的制备和表征及其对铅（II）吸附性能的研究

以低酯果胶和CaCl₂为原料,采用离子交联法制备果胶凝胶珠,然后在果胶凝胶珠表面组装聚间苯二胺,制备新型果胶/聚间苯二胺凝胶珠并用于铅（II）的吸附。采用傅里叶变换红外光谱（FTIR）,扫描电子显微镜（SEM）,X射线衍射（XRD）,热重分析（TGA）,比表面积与孔隙度分析（BET）和能量色散X射线（EDX）对其结构进行了表征,并探究了初始pH、吸附时间、铅（II）初始浓度、吸附剂添加量和共存其它金属离子等条件对铅（II）吸附性能的影响。结果表明,与果胶凝胶珠相比,果胶/聚间苯二胺凝胶珠的比表面积与热稳定性有着显著提高,在相同条件下其对铅（II）的吸附性能更好。吸附过程与朗缪尔等温线模型和准二级动力学模型非常吻合,表明吸附是单分子层并且吸附过程是由化学吸附主导的。果胶/聚间苯二胺凝胶珠对铅（II）的最大吸附容量为352.03 mg/g,远高于果胶凝胶珠（162.99 mg/g）。钠（I）和钙（II）的共存对铅（II）的吸附具有一定程度的抑制作用。在三种重金属离子（铅（II）,铁（II）,铜（II））体系下,果胶/聚间苯二胺凝胶珠对重金属离子的亲和力为铅（II）>铁（II）>铜（II）。吸附铅（II）的机理可能是钙（II）与铅（II）的离子交换,与含氧官能团和含氮官能团的螯合作用以及静电相互作用。在5个吸附/解吸循环后,果胶/聚间苯二胺凝胶珠显示出良好的再生能力（去除率为90%）。果胶/聚间苯二胺凝胶珠可以作为一种去除铅（II）的吸附剂。     

免疫磁珠高通量自动净化-超高效液相色谱法测定粮食中玉米赤霉烯酮

基于免疫磁珠高通量自动净化的前处理方法,使用超高效液相色谱仪对粮食中玉米赤霉烯酮的含量进行测定。首先将免疫磁珠与玉米赤霉烯酮的反应时间、样品提取液和不同粮食基质的净化效果进行优化。经方法验证,超高效液相色谱的检出限和定量限分别为3.5 μg/kg和12.0 μg/kg。在优化条件下,全麦粉和玉米全粉阴性样品的3 个添加水平的加标回收率在99.04%～109.26%之间,变异系数不大于6.88%。玉米全粉、全麦粉、糙米粉、小麦粉等粮食基质中玉米赤霉烯酮成分的国家有证标准物质或质控样品的测定结果在标准值及其扩展不确定度范围内,变异系数不大于3.54%,测定结果较为满意。采用Bland-Altman法对免疫磁珠净化法和免疫亲和柱净化法之间的差异进行分析,结果显示这2 种净化方法的差异在可接受范围内,因此,这2 种方法在净化和富集粮食中玉米赤霉烯酮时可互相代替使用。免疫磁珠净化方法配套使用的真菌毒素全自动净化仪可同时净化10～24 个样品,平均每个样品的净化时间约为2～3 min,实现粮食中玉米赤霉烯酮的高通量自动净化。超高效液相色谱分析速度快、灵敏度高、准确性高,可用于检测粮食中玉米赤霉烯酮的含量。     

Effect of molecular scale roughness of glass beads on colloidal and bacterial deposition

Molecular-scale surface roughness and charge heterogeneity have been hypothesized as factors that can affect the deposition rates of colloids during their transport in porous media. To test their relative importance, a single batch of cleaned glass beads was divided in half and chemically treated with acid or base to alter surface roughness. Analysis of the topography of 20 glass beads with an atomic force microscope (AFM) indicated that the chromic acid-treated (rough) beads had a root-mean-square roughness of 38.1 +/- 3.9 nm, while the sodium hydroxide-treated (smooth) beads had root-mean-square surface roughness of 15.0 +/- 1.9 nm. AFM force volume imaging of glass bead surfaces did not reveal surface charge heterogeneity. Filtration experiments with inorganic colloids (latex microspheres, 1 microm diameter) consistently demonstrated that there was a greater retention of latex microspheres on rough than smooth glass beads suspended in either low (10(-5) M) or higher (10(-1) M) ionic strength (IS) solutions. Collision efficiencies for rough beads were 30-50% larger than for smooth beads. Collision efficiencies of bacteria using rough glass beads were also equal to or greater than those measured for smooth beads. In experiments with the perchlorate-reducing bacterial isolate KJ, collision efficiencies were significantly greater on rough rather than smooth beads for two different ionic strength solutions (IS = 0.05 or 1 M). In another case (IS = 0.1 M) for KJ, and in filtration experiments with E coli, collision efficiencies were not significantly different between the rough and smooth beads. We hypothesize that the consistently greater deposition rates of microspheres, but not bacteria, on rough rather than smooth beads are due in part to the presence of polymers on the surfaces of bacteria.     

Influence of wettability and saturation on liquid-liquid interfacial area in porous media

The knowledge of the area of interfaces between phases is important to understand and quantify many flow and transport processes in porous media. In this work, we apply the interfacial tracer technique to study the dependence of fluid-fluid interfacial area on saturation and wettability. The interfacial area between the wetting and the nonwetting phases (brine and decane) in unconsolidated porous media (glass beads) was measured using an anionic surfactant (3-phenyl decyl benzene sulfonate) as an interfacial tracer. The beads are water-wet; treating them with organosilane rendered them oil-wet. The measurements were done at a series of steady-state fractional flows, providing data at intermediate as well as residual saturations. Flow rates were kept low so that capillary forces controlled the fluid configurations. We observe significant differences in interfacial areas as a function of wetting-phase saturation as the wettability is changed from water-wet to oil-wet. During primary drainage, measured interfacial area increases monotonically with decreasing water saturation in a water-wet medium. In contrast, the interfacial area measured in the oil-wet porous medium increases with decreasing decane saturation, reaches a maximum, and decreases as the residual decane saturation is achieved. The oil-wet experiment is qualitatively consistent with theoretical results that predict the existence of a maximum in fluid-fluid interfacial area during drainage. The water-wet experiment is consistent with theoretical predictions that include the area of grains in pores that have been drained. We conclude that, in the water-wet experiments, the tracer adsorbs at the interface between the nonwetting phase and the wetting films on grains. In the oil-wet experiments, either the oil films are not sustained at high water saturation or the tracer does not adsorb at them, possibly prevented by steric hindrance. Interpretation of interfacial tracer experiments therefore requires care: for some mass transport processes, the thin films of wetting phase on grains will not behave the same as macroscopic volumes of wetting phase.     

Development of carboxymethyl chitosan hydrogel beads in alcohol-aqueous binary solvent for nutrient delivery applications

Carboxymethyl chitosan (CMCS) hydrogel beads were normally prepared from a composite formulation with other polymers, such as alginate. In present study, a novel method was developed to prepare CMCS hydrogel beads in alcohol-aqueous binary solvents. The morphology and shape of the beads were highly dependent on alcohol concentration. The most spherical hydrogel beads were obtained with 3% calcium and 30% alcohol concentration. The chemical crosslinking agent, glutaraldehyde, was needed to maintain the hydrogel integrity and morphology upon drying. Vitamin D3, a model nutrient, was encapsulated into the beads and 96.9% encapsulation efficiency was obtained. The effects of freeze-drying and room temperature drying were studied on the swelling behaviors and release properties in simulated gastrointestinal conditions. Possible mechanisms for CMCS hydrogel beads formation in binary solvents were discussed. The CMCS hydrogel beads prepared in 30% alcohol-aqueous binary solvent may be a promising delivery system for hydrophobic nutrients or drugs.     

Reusable Floating Beads with Immobilized Xylose-Fermenting Yeast Cells for Simultaneous Saccharification and Fermentation of Lime-Pretreated Rice Straw

Novel bioreactor beads for simultaneous saccharification and fermentation (SSF) of lime-pretreated rice straw (RS) into ethanol were prepared. Genetically modified Saccharomyces cerevisiae cells expressing genes encoding xylose reductase, xylitol dehydrogenase, and xylulokinase were immobilized in calcium alginate beads containing inorganic lightweight filler particles to reduce specific gravity. For SSF experiments, the beads were floated in slurry composed of lime-pretreated RS and enzymes and incubated under CO₂ atmosphere to reduce the pH for saccharification and fermentation. Following this reaction, beads were readily picked up from the upper part of the slurry and were directly transferred to the next vessel with slurry. After 240 h of incubation, ethanol production by the beads was equivalent to that by free cells, a trend that was repeated in nine additional runs, with slightly improved ethanol yields. Slurry with pre-saccharified lime-pretreated RS was subjected to SSF with floating beads for 168 h. Although higher cell concentrations in beads resulted in more rapid initial ethanol production rates, with negligible diauxic behavior for glucose and xylose utilization, no improvement in the ethanol yield was observed. A fermentor-scale SSF experiment with floating beads was successfully performed twice, with repeated use of the beads, resulting in the production of 40.0 and 39.7 g/L ethanol. There was no decomposition of the beads during agitation at 60 rpm. Thus, this bioreactor enables reuse of yeast cells for efficient ethanol production by SSF of lignocellulosic feedstock, without the need for instruments for centrifugation or filtration of whole slurry.     

海藻酸钠-纳米纤维素胶粒对乳酸菌胃肠液耐受性的影响

为提高海藻酸钠胶粒对乳酸菌在胃肠液中的保护作用,分别利用豆渣纤维素纳米微纤丝与纤维素纳米微晶协同钙离子交联海藻酸钠包埋乳酸菌制备载菌海藻酸钠-纳米纤维素胶粒,并对海藻酸钠-纳米纤维素胶粒进行微观结构观察、傅里叶变换红外光谱分析、低频氢谱核磁共振分析,同时测定载菌海藻酸钠-纳米纤维素胶粒胃肠消化前后的活菌数量,研究海藻酸钠-纳米纤维素胶粒对乳酸菌胃肠液耐受性的影响。结果表明,纳米纤维素可提高海藻酸钠胶粒的包埋率并减少胶粒表面的孔隙结构,纳米微纤丝较纳米微晶能更好地改善海藻酸钠体系的氢键结合能力,促进海藻酸钠分子链与Ca2＋间形成盐桥,强化凝胶体系的网络结构,从而提高海藻酸钠胶粒的机械强度。进一步研究发现,海藻酸钠-纳米微纤丝胶粒经胃肠液消化后活菌数下降1.51（lg（CFU/g））,显著低于纳米微晶组（2.16（lg（CFU/g）））以及海藻酸钠组（2.99（lg（CFU/g）））（P＜0.05）。综上,纳米微纤丝可作为强化海藻酸钠载体的优良壁材提高乳酸菌的胃肠道耐受性。     

Raw-starch Digestion by Chalara paradoxa Immobilized in Calcium Alginate Gels

The spores of raw starch digesting fungus Chalara paradoxa were entrapped in calcium-alginate beads and preincubated in growth medium. The fungus devoloped a mycelium layer below and on the gel bead surface so that nutrition and oxygen in this area had direct contact with mycelia. The fungus on the bead could produce amylase and could digest raw corn starch continuously for 40 d with corn steep liquor as a nitrogen source.     

壳聚糖/纤维素硫酸酯复合小球的制备及其对BSA吸附性能的研究

以离子液[Emim]Ac为溶剂,采用挤球法制备壳聚糖/纤维素硫酸酯(CHT-CS)复合小球,探索制备条件,并用FT-IR、SEM和XRD对其进行表征。将复合小球用于吸附牛血清蛋白(BSA),考察影响CHT-CS吸附BSA的因素。结果表明:制备复合小球的最佳条件是纤维素酸酯的取代度为0.58,复合原料液的浓度为5%,壳聚糖:纤维素硫酸酯为1:1;纤维素硫酸酯和壳聚糖在制备过程中发生了复杂的相互作用,形成了结构稳定,表面和内部均存在大量沟壑和孔洞的小球;所制备的复合小球对BSA的最大平衡吸附量达到157 mg/g,高于其他壳聚糖复合材料;当BSA初始浓度1 mg/m L、溶液p H为5左右,小球对BSA的吸附量最大;一定范围内增加小球投加量在可增大BSA吸附量。本研究结果为分离纯化BSA和CHT-CS复合小球固定化酶等方面的应用提供了参考。     

Encapsulation of extract prepared from irradiated onion scales in alginate beads: a potential functional food ingredient

Onion scales were irradiated and the effects of irradiation on their bioactive properties were studied. The antioxidant and antibacterial activities of extract prepared from irradiated onion scales (upto 6 kGy) were comparable to the extract prepared from non-irradiated onion scales. OSE (0–6%) were encapsulated in 2% alginate beads. The beads containing 6% OSE had the highest a* and the lowest L* values as compared to neat beads that were prepared without OSE. The size of the beads reduced significantly from 2.42 mm (0% OSE) to 2.05 mm (6% OSE). The moisture content of neat (0% OSE) beads was 95.94% as compared to 93.86% in beads incorporated with 6% OSE. Alginate beads containing 6% OSE had the maximum swelling capacity. On basis of DPPH radical scavenging antioxidant assay it was observed that alginate beads containing 6% OSE showed the maximum antioxidant activity. In simulated gastric and intestinal fluid, the antioxidant activity of the beads containing OSE was retained. Irradiated minced chicken muscles containing 6% OSE alginate beads had lower TBARS value (2.0 mg MDA kg^?1 meat) as compared to 3.3 mg MDA kg^?1 meat for irradiated meat with 0% OSE. There was significant difference (almost 2 log cycle reduction) in the growth of Staphylococcus aureus, Pseudomonas fluorescens in chicken muscle during chilled storage when OSE encapsulated beads were incorporated. Hence, irradiation of onion scales and its encapsulation in alginate beads has a great potential as a functional ingredient in various food products.     

Whey protein/alginate beads as carriers of a bioactive component

Bioactive components encapsulated in gel particles offer a means to deliver these components in a time release fashion to improve health through daily diet. The objective of this work was to evaluate the physical/mechanical properties of a release system consisting of whey protein/alginate gel beads in a model beverage. Riboflavin, vitamin B₂, was incorporated in the gel beads as a model bioactive compound. Gel beads were formed both with and without riboflavin and then added to a xanthan/sucrose suspending medium. Both the beads and the polymer solutions from which they were formed were characterized by standard rheological methods. An absorbance method was used to monitor riboflavin release over time. NMR and MRI (magnetic resonance imaging) methods characterized bead integrity and the state of protons in the gel beads. The combination of whey protein and alginate formed beads with good integrity and zero order rate kinetics for the release of riboflavin. The release rate of the bioactive component was more rapid that the typical shelf life of a bottled beverage however, the work represents a step toward the design of this type of functional food through characterization of the encapsulation medium.     

Comparison of alginate and pectin based beads for production of poultry probiotic cells

A comparative study on the stability and potential of alginate and pectin based beads for production of poultry probiotic cells using MRS medium in repeated batch fermentation was conducted. The bead cores, made of three types of materials, i.e., ca-alginate, ca-pectinate and ca-alginate/pectinate, were compared. The effect of single and double layer coatings using chitosan and core material, respectively, on the bead stability and cell production were also studied. The pectin based beads were found to be more stable than that of the alginate beads and their stability was further improved by coating with chitosan. The cell concentration in pectin based beads was comparable to that in the alginate beads. On the other hand, pectin based beads gave significantly lower cell concentration in the growth medium for the initial fermentation cycles when compared to the alginate beads. In conclusion, pectin was found to be potential encapsulation material for probiotic cell production owing to its stability and favourable microenvironment for cell growth.     

Protection of bifidobacteria encapsulated in polysaccharide-protein gel beads against gastric juice and bile

Bifidobacterium cells were encapsulated in a mixed gel composed of alginate, pectin, and whey proteins. Two kinds of capsules were obtained: gel beads without membranes and gel beads with two membranes formed by the transacylation reaction. In vitro studies were carried out to determine the effects of simulated gastric pH and bile salts on the survival of free and encapsulated Bifidobacterium bifidum. The protective effects of gel beads without membranes and gel beads coated with two membranes formed by the transacylation reaction were evaluated. After 1 h in an acidic solution (pH 2.5), the free-cell counts decreased by 4.75 log units, compared with a <1-log decrease for entrapped cells. The free cells did not survive after 2 h of incubation at pH 2.5, while immobilized-cell counts decreased by about 2 log units. After incubation (1 or 3 h) in 2 and 4% bile salt solutions, the bifidobacterium mortality level for membrane-free gel beads (4 to 7 log units) was higher than that for free cells (2 to 3 log units). However, counts of bifidobacteria immobilized in membrane-coated gel beads decreased by <2 log units. Cell encapsulation in membrane-coated protein-polysaccharide gel beads could be used to increase the survival of healthy probiotic bacteria during their transit through the gastrointestinal tract.     

冬瓜彩珠饮料的加工技术

以冬瓜为原料,采用纯天然物质着色,生产一种冬瓜彩珠饮料,彩珠均匀悬浮于饮料中,既具有一定的观赏性,又具有咀嚼性。     

研磨条件对UV喷墨油墨分散性的影响

UV喷墨油墨对分散性要求很高,而研磨条件对油墨的分散性有很大的影响。为了获得分散性良好的UV喷墨油墨,在固定油墨配方的条件下,通过改变研磨时研磨珠的大小、以及将不同大小的研磨珠以一定比例混合研磨油墨,测试不同研磨时间获得的油墨粒径大小分布,从而考察研磨珠的大小以及研磨时间对油墨分散性的影响。实验结果表明：研磨珠越小,研磨效果越好,直径为1.0－1.2mm的研磨珠研磨得到的油墨,95%的粒径在0.972μm以下;只有在最佳研磨时间下才能获得分散性良好的油墨,且不同大小研磨珠的最佳研磨时间不同,直径为2.0－2.2mm、1.6－1.8mm、1.0－1.2mm的研磨珠对应的最佳研磨时间分别为105m in、105m in、90m in;中小珠混合比为1∶1研磨得到的油墨的分散性最好,油墨90%的粒径在0.656μm以下。     

Investigation of alginate beads for gastro-intestinal functionality,Part 1: In vitro characterisation

This paper summarises the work undertaken to characterise the physico-chemical properties of alginate gel beads in simulated gastro-intestinal (GI) conditions. Two types of alginate beads were investigated: “strong” (strongly gelled) and “weak” (weakly gelled) beads prepared by long and short exposure to a calcium chloride gelling bath, respectively. The beads were found to shrink in gastric conditions and swell in intestinal conditions due to changes in electrostatic forces in the gel matrix at the different pH and ionic strength conditions. We found a good correlation between the NMR transverse relaxation time (T₂) of the water protons within the gel and alginate concentration which was dependant on environmental conditions. T₂ shortening was observed in gastric conditions reflecting the formation of a more dense gel network on shrinking. In intestinal conditions, T₂ increased reflecting the formation of a more open, porous gel network on swelling. This was corroborated by electron microscopy which clearly depicted the changes in gel density in simulated GI conditions. The mechanical properties of the beads similarly reflected the changes in the gel microstructure with the beads becoming stronger in gastric conditions and weaker in intestinal conditions, respectively. The beads were shown to eventually disintegrate towards the end of the intestinal phase which may make these alginate gel beads an attractive option as controlled delivery devices in the gastro-intestinal tract. The in vivo behaviour of the beads within the GI tract is investigated using non-invasive magnetic resonance imaging in the second paper of this series.