牛白蛋白包裹复合磁性微球的制备及性能表征

首先在反相(W/O)微乳液体系中制备出Fe3O4/PAM(聚丙烯酰胺)磁性微球;然后在牛白蛋白的磷酸氢二钠-柠檬酸缓冲溶液中,以戊二醛为交联剂,加入Fe3O4/PAM微球,使蛋白质特异性吸附在微球上。采用电子衍射、透射电镜、差热、热重、红外光谱等方法对复合微球的粒径、结构等性质进行了表征与分析。并考察了牛白蛋白的浓度、pH以及保温时间对蛋白质吸附程度的影响。结果显示,微球粒径20 nm左右,粒径均匀;微球具有较大吸附量;pH增大使蛋白质的吸附量减小;在一定范围内,增大蛋白质初始浓度和延长保温时间均有利于增加蛋白质的吸附量。     

磁性聚胺基微球固定化脂肪酶催化性质

以平均粒径为62.44μm,等电点为9.6的磁性聚胺基微球为载体吸附固定化猪胰腺脂肪酶。结果表明:固定化酶的最适反应pH比自由酶低,最适反应温度比自由酶高,对金属离子和温度具有更好的耐受性。固定化后,脂肪酶动力学米氏常数减小,最大反应速度下降,酶催化反应活化能分别为17.16 kJ/mol(固定化酶)和15.28 kJ/mol(自由酶)。     

表面修饰聚乙烯亚胺的壳聚糖微球对十二烷基苯磺酸钠的吸附特性

采用乳化交联法制备交联壳聚糖微球(CCS),在其表面接枝聚乙烯亚胺(PEI),得到系列具有不同离子交换容量(IEC)的PEI修饰交联壳聚糖微球(PEI-CCS),对其进行表征,考察了其对十二烷基苯磺酸钠(SDBS)的静态吸附特性. 结果表明,PEI-CCS平均粒径为85 mm,IEC最高达1275 mmol/g,远高于CCS的418 mmol/g. 酸性条件下,PEI-CCS的胺基质子化,带正电荷,能与溶液中的阴离子吸附结合,对SDBS有良好的吸附能力. 吸附过程自发放热,可用准二级动力学模型和Langmuir吸附等温模型描述. PEI-CCS对SDBS的最大吸附量随IEC增加而增大,IEC=1275 mmol/g的PEI-CCS的最大吸附量为1487.61 mg/g,是CCS最大吸附量(510.20 mg/g)的2.92倍,吸附-脱附7次循环后,吸附量下降17.8%. PEI-CCS具有良好的重复使用性.     

交联壳聚糖微球的制备及其对不同pH有机染料的吸附性能

本文以壳聚糖为原料,戊二醛为交联剂,采用乳化交联法制备了交联壳聚糖微球。并通过红外光谱仪(FT-IR)、X射线衍射仪(XRD)、扫描电镜(SEM)对壳聚糖和交联壳聚糖微球的结构与形貌进行表征,使用紫外/可见分光光度计测试了甲基橙溶液的吸收波长及吸光度。主要研究了不同p H条件下交联壳聚糖微球对甲基橙溶液的吸附脱色效果。结果表明:交联壳聚糖微球形状规则、表面光滑,其粒径为100μm左右;当甲基橙溶液p H值为3时,吸附速率最快;动力学研究结果表明该吸附过程符合准二级吸附动力学方程模型。     

粒径相关的海藻酸盐/壳聚糖微球膜性能

粒径是评价微尺度凝胶载体性能的重要参数。文中以3种不同粒径(202,413,809μm)的海藻酸钙(Ca-Alg)凝胶珠为研究对象,以维生素B_(12)(VB_(12))、牛血清白蛋白(BSA)和壳聚糖(CS)为模型分子,实验考察了胶珠粒径对海藻酸钙/壳聚糖(Ca-Alg/CS)微球性能的影响。采用电子扫描显微镜(SEM)、傅里叶红外光谱仪(FTIR)和激光共聚焦显微镜(CLSM)等方法表征膜结构与形貌,采用膨胀率表征膜稳定性。结果表明:Ca-Alg/CS微球的凝胶结构、分子扩散性能和聚电解质复合膜性能与Ca-Alg胶珠粒径具有相关性。随着胶珠粒径减小,凝胶结构趋于致密,对分子扩散阻力增大。在成膜反应过程中,小粒径胶珠表面为成膜反应提供了更多的反应交联位点,在胶珠表面形成更致密连续和更厚的聚电解质复合膜。Ca-Alg/CS微球具有优异的膜强度和稳定性,在细胞固定化培养中具有显著应用优势。     

超大孔聚丙烯酰胺晶胶微球的制备及其生物相容性和吸附性能

利用反相悬浮结合溶剂结晶致孔法制备了具有超大孔隙、球形度良好的聚丙烯酰胺晶胶微球,晶胶微球平均粒径为234.1μm,孔径约为10~50μm。采用原位接枝法,将2-丙烯酰胺基-2-甲基-1-丙烷磺酸(AMPSA)接枝到晶胶微球孔隙表面上,得到了带有磺酸基团的阳离子交换晶胶微球。考察了晶胶微球的生物相容性和吸附蛋白质及重金属离子Cu2+的性能,结果表明:在大肠杆菌培养液中,添加晶胶微球,对大肠杆菌的生长影响不大。接枝了AMPSA的晶胶微球表现出更强的吸附Cu2+的能力,吸附容量达到1.14 mmol·g-1。同时,接枝后的晶胶微球也具有一定吸附蛋白质的能力,溶菌酶的吸附容量达到54.5 mg·g-1。因此,该大孔晶胶可望在微生物固定化、生物分离和重金属离子吸附中会发挥更大的作用。     

糠醛渣木质素/聚乙烯亚胺微球的制备

木质素和聚乙烯亚胺（PEI）对重金属离子有良好的亲和力，且木质素来源广泛、具有良好的生物降解性能，在水处理方面有很好的前景。本文以糠醛渣木质素和聚乙烯亚胺为主要原料，十二烷基苯磺酸钠（SDBS）为分散剂，环氧氯丙烷（EPI）为交联剂，液体石蜡为油相，采用反相悬浮聚合法，制备了糠醛渣木质素/PEI微球（LMS）。通过FTIR、XRD、SEM和激光粒度仪对微球的结构和形貌进行表征，研究了木质素用量、PEI用量、EPI用量、SDBS用量、油水比和反应温度对木质素微球制备的影响。结果显示，在木质素用量为0.600g，PEI用量为2.25g，EPI用量为2.25mL，SDBS用量为0.075g，温度为56℃，油水体积比为4.5∶1的条件下，制得的糠醛渣木质素/PEI微球平均粒径为135μm，粒径分散度为0.290，比表面积为46.5m²/g，球型度良好，球体表面有少量微孔。     

淀粉基阴离子微球的制备

以可溶性淀粉为原料,N’N-亚甲基双丙烯酰胺(MBAA)及环氧氯丙烷(ECH)为交联剂,先在反向悬浮体系中采用两步交联法制备了中性淀粉微球,再用K3P3O9与中性淀粉微球反应制得淀粉基阴离子微球。以微球的平均粒径为指标,利用扫描电镜(SEM)和光透式粒度分析仪对产物进行了表征。结果表明,反应时间为2.5 h,淀粉溶液浓度为15%,油相与水相的体积比为3∶1,MBAA用量为0.4 g,乳化剂用量为1.0 g时,微球平均粒径分布较为均一,粒径在65μm以下的微球占95.5%,球形圆整,表面粗糙多孔,可用作药物载体和吸附剂。     

反相悬浮—化学交联法制备聚乙烯醇交联微球CPVA

以聚乙烯醇（PVA）为单体,戊二醛（GA）为交联剂,山梨醇酐单硬脂酸酯（span-60）为分散剂,采用反相悬浮-化学交联法,制备了聚乙烯醇交联微球CPVA。采用FT-IR和SEM对其化学结构和微观形貌进行了表征,考察了搅拌速率、交联剂的用量、催化剂（盐酸）的用量对交联微球的成球性能及粒度的影响规律。结果表明,在反相悬浮体系中,搅拌速度、交联剂的用量是影响交联微球制备的主要因素,当搅拌速度小于250r/min、交联剂的用量大于2mL时,体系中均不能成球。在体系中加入盐酸后,交联微球的粒径随盐酸用量的增大而增大,控制成球的反应条件可以制备出球形度良好、粒径在150μm左右的粒径可控的聚乙烯醇交联微球CPVA。     

超大孔聚丙烯酰胺晶胶微球的制备及其生物相容性和吸附性能

利用反相悬浮结合溶剂结晶致孔法制备了具有超大孔隙、球形度良好的聚丙烯酰胺晶胶微球,晶胶微球平均粒径为234.1 mm,孔径约为10～50 mm。采用原位接枝法,将2-丙烯酰胺基-2-甲基-1-丙烷磺酸（AMPSA）接枝到晶胶微球孔隙表面上,得到了带有磺酸基团的阳离子交换晶胶微球。考察了晶胶微球的生物相容性和吸附蛋白质及重金属离子Cu²⁺的性能,结果表明：在大肠杆菌培养液中,添加晶胶微球,对大肠杆菌的生长影响不大。接枝了AMPSA的晶胶微球表现出更强的吸附Cu²⁺的能力,吸附容量达到1.14 mmol·g^-1。同时,接枝后的晶胶微球也具有一定吸附蛋白质的能力,溶菌酶的吸附容量达到54.5 mg·g^-1。因此,该大孔晶胶可望在微生物固定化、生物分离和重金属离子吸附中会发挥更大的作用。     

微球材料尺寸和结构控制的过程工程

微球材料的粒径均一性和结构可控性直接影响其应用效果,这对过程工程提出了挑战。在发展微孔膜乳化过程制备均一乳液和微球的基础上,对均一乳液的形成机理进行了研究,通过对液滴形成过程的控制,在油/水、水/油、水/油/水等体系成功制备出了均一微球。通过发展微球结构演变过程的定量研究方法,成功对微球结构进行了调控;针对生化工程对超大孔微球的重要需求,发展了超大孔微球制备方法,实现了孔径在100 nm到微米级的调控。研究了粒径均一性和结构对其应用效果的影响。微球应用于生物分离介质时,粒径均一性提高了蛋白质的分离度;超大孔微球可使超大生物分子快速进入介质内部,显著提高纯化回收率。微球应用于胰岛素口服药物载体时,粒径对其在消化道的分布有显著影响,中空-多孔微球显示了最佳的降血糖效果。     

空心壳聚糖微球对二甲酚橙的吸附性能研究

采用反相悬浮交联法制备了具有空壳结构的壳聚糖微球。利用静电引力对二甲酚橙的进行吸附研究。通过分光光度法探讨了溶液初始DH值、吸附时间、二甲酚橙的初始质量浓度、吸附剂的用量及其粒径大小对二甲酚橙的吸附率的影响。结果表明：在DH值为4．90及常温下,二甲酚橙溶液的初始质量浓度为32mg／L时,可达到吸附平衡,此时的吸附剂用量为0．03g／100mL,吸附平衡时间约为2h,吸附率可高达93．6％。结果表明,此微球具有很强的吸附能力,而且平衡时间快,并且具有一定的重复利用的性能,是一类很值得开发的新型吸附分离材料。     

纳米聚合物微球的封堵性及驱油性能

聚合物纳米微球因其对水、温度和矿化度具有良好抵抗力以及较低的使用成本而受到更多关注,作为一项新型调驱技术,可大幅提高油田采油效率。为了更好地认识聚合物纳米微球的驱油效果,开展了聚合物纳米微球的封堵及驱油研究。进行了微通道驱替实验,透过滤膜实验,通过激光粒度仪分析了溶胀后微球的尺寸变化,通过透射电镜观察了微球乳液,并研究了空气中微球乳液与干粉的表面张力。结果显示,在50和100 nm微球的微通道实验中都观察到了微米级别的团聚物,扩大了水分散体系的波及体积,2种纳米聚合物微球都会出现一定程度的团聚行为,具有溶胀性能,还发现了微球和乳化剂、油滴之间的缠结现象。微球乳液中含有的表面活性剂使其表面张力降低,从而提高了驱油效率。对纳米微球的封堵性能和驱油性能进行了研究,对揭示纳米微球的驱油机理和产品的可持续发展与创新具有显著意义。     

Human serum albumin (HSA) adsorption with chitosan microspheres

In this study, chitosan microspheres were prepared and characterized for adsorption of human serum albumin (HSA) as affinity sorbent. The chitosan microspheres were obtained with a “suspension crosslinking technique” in the size range of 30–700 μm by using a crosslinker, i.e., glutaraldehyde. The chitosan microspheres used in HSA adsorption studies were having the average size of 170 ± 81 μm. Adsorption medium pH and the initial HSA concentration in the adsorption medium were changed as 4.0–7.0 and 0.5–2.0 mg HSA/mL, respectively, to investigate the HSA adsorption capacity of chitosan microspheres. Maximum HSA adsorption (i.e., 11.35 mg HSA/g chitosan microspheres) was obtained at pH 5.0 and 1.5 mg HSA/mL of the initial HSA concentration in the adsorption medium was obtained as the saturation value for HSA adsorption. A very common dye ligand, i.e., Cibacron Blue F3GA was attached to the chitosan microspheres to increase the HSA adsorption capacity. Actually, the HSA adsorption capacity was increased up to 15.35 mg HSA/g chitosan microspheres in the case of Cibacron Blue F3GA attached to chitosan microspheres used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3035–3039, 2002     

Preparation of Porous Calcium Alginate Membranes/Microspheres via an Emulsion Templating Method

Summary: A method is presented that can produce ordered macroporous alginate membranes and microspheres with a relatively narrow pore size distribution as compared to other existing porous alginate matrix generating procedures. The calcium alginate membranes and microspheres obtained were multiporous, and the pore size could readily be adjusted in the range of 1 to 10 µm by selecting appropriate initial emulsion parameters. A preliminary set of experiments was used to determine a range of conditions suitable for the formation of stable O/W emulsions consinsting of the alginate solution, liquid paraffin and surfactants. The obtained emulsions were characterized by size distribution measurements and optical microscopy. The emulsions were used to form alginate membranes and microspheres with diameters of 150–500 µm. Subsequent work was performed to remove liquid paraffin droplets, the dispersed phase of the emulsion which acted as template in the pore‐generating process, from the final alginate membranes and microspheres. The states of templates in hydrogels and the effect of template removal on the calcium alginate structures were thoroughly investigated.

Porous alginate membranes prepared via emulsion templating method.     

Synthesis and characterization of injectable chitosan cryogel microsphere scaffolds

Treatment of tissue defects involves invasive processes such as implanting the tissue engineered scaffold to the defected area. Injectable scaffolds are increasingly being developed to achieve tissue regeneration in a less invasive manner. In this study, injectable chitosan cryogels in the form of microspheres were synthesized combining the water in oil emulsification method with the crosslinking of microspheres during cryogelation. The effects of polymer ratio, crosslinker concentration, cryogelation temperature, and stirring speed on the resulting cryogels’ chemistry, pore morphology, microsphere size, swelling ratio, degree of crosslinking, and degradation rate were examined for a possible noninvasive tissue engineering application. Microspheres with optimized properties were developed with an average pore and particle size of 5.50?±?0.63 and 220.11?±?25.58?µm at a chitosan ratio of 1%, glutaraldehyde concentration of 3%, reaction temperature of ?16°C, and stirring rate of 1,000?rpm.     

季铵化两亲性壳聚糖衍生物载药性质研究

合成新型季铵化两亲性壳聚糖衍生物(DEAE-CMC)。用乳化交联固化法制备DEAE-CMC/VB12载药微球。用激光粒径仪、扫描电镜对微球的大小和形态进行表征。载药微球的平均粒径为4.53μm。在pH=7.4磷酸盐缓冲溶液中,DEAE-CMC/VB12载药微球体外药物释放达到平衡时间为60 h,药物包封率为33.70%,载药量为12.47%,平衡时药物累积释放率为56.30%。     

K88 Fimbrial Adhesin Targeting of Microspheres Containing Gentamicin Made with Albumin Glycated with Lactose

The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88) was investigated. Glycated albumin with lactose (BSA-glucose-β (4-1) galactose) was used as the microsphere matrix (MS-Lac) and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3) were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10–17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections.     

Polystyrene/melamine-formaldehyde hollow microsphere composite by self-assembling of latex particles at emulsion droplet interface

Submicron scale particle aggregates with defined shape were prepared by self-assembling of sulphonated polystyrene latex particles at the interface of emulsion droplets. Several parameters were considered during the preparation, including the sulphonation time of the polystyrene latex particles, the composition of the oil phase, and the zeta potential of the sulphonated latex particle. To further improve the mechanical stability of the particle aggregates, a hard composite layer was formed by addition of melamine-formaldehyde (MF) prepolymer into the emulsion. The prepolymer was crosslinked onto the particles surface of sulphonated PS particle aggregates. The crosslinking reaction was catalysed by the acidity of sulfogroup. After evaporating off solvent, PS/MF hollow microsphere composites were obtained as mechanically stable dry material. The hollow microsphere composite was characterized by TGA, FTIR, optical microscopy, scanning and transmission electron microscopy.