臭氧氧化去除水中泰乐菌素的研究

探究了臭氧预氧化方法对水环境中普遍存在的泰乐菌素的去除效率,研究了泰乐菌素初始浓度、溶液p H值、臭氧投量和腐殖酸对臭氧氧化去除泰乐菌素效率的影响。结果表明,氧化反应20 min后,泰乐菌素的去除率基本稳定。随泰乐菌素初始浓度的增加,其去除率呈降低趋势;溶液p H值对泰乐菌素的去除率存在一定影响,泰乐菌素的去除率随溶液p H的增加而降低;随臭氧投量的增加,泰乐菌素去除率也随之升高;腐殖酸对泰乐菌素的氧化去除有一定的抑制作用,且浓度越高,抑制作用越强烈。     

臭氧氧化去除水中泰乐菌素的研究

探究了臭氧预氧化方法对水环境中普遍存在的泰乐菌素的去除效率,研究了泰乐菌素初始浓度、溶液p H值、臭氧投量和腐殖酸对臭氧氧化去除泰乐菌素效率的影响。结果表明,氧化反应20 min后,泰乐菌素的去除率基本稳定。随泰乐菌素初始浓度的增加,其去除率呈降低趋势;溶液p H值对泰乐菌素的去除率存在一定影响,泰乐菌素的去除率随溶液p H的增加而降低;随臭氧投量的增加,泰乐菌素去除率也随之升高;腐殖酸对泰乐菌素的氧化去除有一定的抑制作用,且浓度越高,抑制作用越强烈。     

提高3-O-乙酰基4”-O-异戊酰基泰乐菌素产量和降低生产成本的方法

本发明是在发酵法合成泰乐菌素衍生物3-O-乙酰基4”-O-异戊酰基泰乐菌素时，向发酵液中补入高浓度的L-亮氨酸溶液或固体悬浮液和高浓度的泰乐菌素溶液，及使用成本较低的液化淀粉液及成本较低的泰乐菌素半成品或中间体作为发酵过程中的补料物，比现有工艺过程显著提高产量及降低生产成本。     

薄层色谱法分离泰乐菌素微生物降解产物的研究

研究了越南伯克霍尔德氏菌(Burkholderia vietnamiensis)对泰乐菌素的降解效能,并通过薄层色谱法初步分离其降解产物。结果表明:用B.vietnamiensis处理初始浓度为100 mg·L~(-1)泰乐菌素药渣5 d,降解率为97.70%。用薄层色谱法初步分离的泰乐菌素降解产物,以甲醇/乙酸乙酯为展开剂,当比例调至1∶6时,可将产物初步分离为两种,降解产物A的Rf A为0.43,降解产物的Rf B为0.28;降解产物经展开后在紫外灯下可显色,说明泰乐菌素分子结构中共轭体系依然存在。     

泰乐菌素单克隆抗体的制备及竞争ELISA检测方法的建立

目的制备泰乐菌素(Tylosin)单克隆抗体,并建立泰乐菌素竞争ELISA检测方法。方法用羰基二咪唑将半抗原泰乐菌素分别与牛血清白蛋白(BSA)和卵清蛋白(OVA)偶联,制备泰乐菌素免疫抗原Tylosin-BSA和检测抗原Tylosin-OVA,用紫外光谱扫描检测Tylosin-BSA偶联物,辣根过氧化物酶标记Tylosin-OVA偶联物。采用杂交瘤技术,制备特异性抗泰乐菌素单克隆抗体,建立泰乐菌素竞争ELISA检测方法。结果筛选出2株稳定分泌抗泰乐菌素单抗的杂交瘤细胞株3E4和2G10,2G10分泌的单抗腹水效价为6×10-4,抗体类型为IgG1型,轻链为κ链,在酸、碱及热条件下均较稳定。选择该单抗建立了泰乐菌素竞争ELISA检测方法。该方法灵敏度达50ng/ml,标准曲线线性关系良好(r=0.9827),且特异性、稳定性较好,准确性、精密性较高。结论已成功制备了泰乐菌素单克隆抗体,并建立了竞争ELISA检测方法,可用于动物源性食品中残留泰乐菌素含量的检测。     

膜分离技术分离纯化泰乐菌素的研究

简要介绍膜分离技术,采用超滤膜、纳滤膜对泰乐菌素发酵液进行脱色除蛋白试验。通过考查该体系膜通量、发酵液浓缩情况及滤液质量等,发现采用膜系统处理泰乐菌素发酵液在工艺、技术上是可行的,比传统过滤方式具备很多优越性。     

高效液相色谱法测定废水中泰乐菌素残留量

对废水中残留的泰乐菌素进行了检测。废水水样经ODS-SPE固相萃取柱分离净化后,采用高效液相色谱进行测定。以乙腈和0.5%磷酸溶液为流动相,在282 nm处对泰乐菌素进行紫外检测。该方法在0.2～5.0 g/L之间有良好的线性相关性,相关系数R2=0.999 3,回收率为95.4%～101%,相对标准偏差为3.4%～4.2%,方法检出限为0.088 7 mg/L。     

泰乐菌素提取过程中乙酸丁酯回收方法的研究

在泰乐菌素提取过程中，乙酸丁酯的回收决定了提取质量，本文对乳化层中乙酸丁酯的回收方法进行研究，结果回收了大部分的乙酸丁酯，减少了环保的压力，增加产品的收率，降低了生产成本，在同行业具有很强的竞争力。     

不同UV光氧化工艺的阿特拉津降解动力学研究

UV光照条件下,研究了反应条件对农药阿特拉津(ATZ)光氧化降解的影响规律与作用机理。结果表明,ATZ在不同UV光氧化工艺中的降解反应均符合准1级反应动力学,溶液pH对降解速率均存在较大影响。单独UV工艺中,ATZ在不同溶液pH下的降解速率、产物生成及形态差异,导致ATZ水溶液的紫外-可见(UV-Vis)吸收光谱存在一定差别。UV/H_2O_2工艺中,ATZ的降解速率随H_2O_2加入量的增加呈现先增大后降低的变化趋势,ATZ溶液在pH分别为7.0和10.0时的UV-Vis吸收光谱的变化趋势与幅度相似,但与pH为4.0时的差别较大。UV/Ti O_2工艺中,ATZ的降解速率随Ti O_2加入量的增加而降低;H_2O_2和Ti O_2同时加入到反应体系时,ATZ降解速率均低于二者单独加入时的降解速率。     

聚丁二酸丁二醇酯(PBS)在不同pH条件下的降解

对聚丁二酸丁二醇酯(PBS)薄膜在不同pH值水溶液中的降解进行对比研究.用失重率及薄膜表面形貌观察等时降解结果进行表征,结果表明:PBS薄膜在不同pH值水溶液中的降解速度为:碱性溶液>酸性溶液>中性溶液.降解过程中不同降解溶液的pH值均有一定程度的下降.     

Silk I structure formation through silk fibroin self-assembly

Regenerated silk fibroin films are normally produced by increasing the Silk II structure (β-sheet content). In the present study, silk fibroin films were prepared by controlling the environmental temperature and humidity, resulting in the formation of silk films with a predominant Silk I structure instead of Silk II structure. Wide angle X-ray diffraction indicated that when the relative humidity was 55%, the silk films prepared were mainly composed of Silk I structure, whereas silk films formed on other relative humidity had a higher Silk II structure. Fourier transform infrared analysis (FTIR) results also conformed that the secondary structure of silk fibroin can be controlled by changing the humidity of the films formed process. Thermal analysis results revealed Silk I structure was a stable crystal, and the degradation peak increased to 320°C, indicating a greater thermal stability of these films formed under the 55% relative humidity conditions. Atomic force microscopy (AFM) results depicted silk fibroin in the fresh solution had many nanospheres existing with 20–50 nm diameters and mainly maintained a random coil structure without specific nanostructures. At the same time, it also illustrated the self-assembly process of silk fibroin in the aqueous solution without any human intervention. In addition, this present study also provided additional support for self-assembly mechanism of silk fibroin films formation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Analyzing the interactions and miscibility of silk fibroin/mucin blends

Mucin, a glycoprotein with viscoelastic properties, and silk fibroin, a protein excreted from silkworms with properties of thermal and mechanical resistance, have been probed as building blocks in the design of biomaterials. Aiming to evaluate the interaction and miscibility between mucin and fibroin, we synthesized silk fibroin and mucin (SF/MU) blends for biomedical applications. The morphological analysis of the SF/MU blends showed the presence of two phases, suggesting a partial miscibility between the polymers. The degradation temperature of the SF/MU blends increased with an increase in the silk fibroin content, indicating that silk fibroin contributed to the thermal stability of the blends. The glass transition temperature of the SF/MU blends lay between the values of the pure polymers. The Fourier-transform infrared spectroscopy results pointed out that the interaction between fibroin and mucin occurred between the amine group of silk fibroin and mucin carboxyl and hydroxyl groups. The outcomes of this work provided essential information on the miscibility of the SF/MU blends. These findings will be critical for further studies with fibroin and mucin-based biomaterials, especially in mucoadhesive systems and wound healing applications.     

Three-dimensional fibroin/collagen scaffolds derived from aqueous solution and the use for HepG2 culture

Although three-dimensional fibroin scaffolds have been prepared with freeze–drying method, these scaffolds still cannot meet the requirements of tissue engineering. In this article, a new process is described to form fibroin-based porous scaffolds with controllable structure and morphological features. When collagen was added to fibroin solution, the viscosity of the blend solution increased because of the interaction between fibroin and collagen, and then it restrained the unwanted fibroin leaf formation in freezing process that generally appeared in the previous fibroin scaffold preparation. With methanol treatment, the fibroin/collagen scaffolds became water-stable, following the transition from random and -helix to β-sheet conformation. The aqueous-fibroin porous scaffolds had highly homogeneous and interconnected pores with pore sizes ranging from 127 to 833 μm, depending on the fibroin concentration. The porosity of scaffolds was >90%, and the yield strength and modulus were up to 354±25 kPa and 30±0.1 MPa, respectively, when the blend solution, containing 20% collagen, maintained 4% fibroin concentration. Adhesion, spreading and proliferation of HepG2 cells on fibroin and fibroin/collagen blend scaffolds were also observed to investigate the biocompatibility. Scanning electron microscopy (SEM) and MTT analyses demonstrated that the adding of collagen evidently facilitated HepG2 attachment and proliferation in vitro. These new fibroin based three-dimensional scaffolds provided much more excellent properties due to the greatly improved control of pore size, the uniform pore distribution, the hydrophility, the mechanical properties and the biocompatibility compared with those of reported three-dimensional fibroin scaffolds.     

The preparation of high performance silk fiber/fibroin composite

An all-silk composite, in which uniaxially-aligned and continuous-typed Bombyx mori silk fibers were embedded in a matrix of silk protein (fibroin), was successfully prepared via a solution casting process. The structure, morphology, mechanical and thermal properties of such silk fiber/fibroin composites were investigated with X-ray diffraction, scanning electron microscopy, tensile and compression tests, dynamic mechanical analysis and thermogravimetric analysis. The results demonstrated that the interface adhesion between silk fiber and the fibroin matrix was enhanced by controlling the fiber dissolution through 6 mol L⁻¹ LiBr aqueous solution. Compare to those of the pure fibroin counterparts, the overall mechanical properties as well as the thermal stability of such silk fiber/fibroin composites were significantly improved. For example, the composite with 25 wt% fibers showed a breaking stress of 151 MPa and a breaking elongation of 27.1% in the direction parallel to the fiber array, and a compression modulus of 1.1 GPa in the perpendicular direction. The pure fibroin matrix (film), on the other hand, typically had a breaking stress of 60 MPa, a breaking elongation of 2.1% and a compression modulus of 0.5 GPa, respectively. This work suggests that such a controllable technique may help in the preparation of animal silk based materials with promising properties for various applications.     

Chemical,Thermal, Time,and Enzymatic Stability of Silk Materials with Silk I Structure

The crystalline structure of silk fibroin Silk I is generally considered to be a metastable structure; however, there is no definite conclusion under what circumstances this crystalline structure is stable or the crystal form will change. In this study, silk fibroin solution was prepared from B. Mori silkworm cocoons, and a combined method of freeze-crystallization and freeze-drying at different temperatures was used to obtain stable Silk I crystalline material and uncrystallized silk material, respectively. Different concentrations of methanol and ethanol were used to soak the two materials with different time periods to investigate the effect of immersion treatments on the crystalline structure of silk fibroin materials. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman scattering spectroscopy (Raman), Scanning electron microscope (SEM), and Thermogravimetric analysis (TGA) were used to characterize the structure of silk fibroin before and after the treatments. The results showed that, after immersion treatments, uncrystallized silk fibroin material with random coil structure was transformed into Silk II crystal structure, while the silk material with dominated Silk I crystal structure showed good long-term stability without obvious transition to Silk II crystal structure. α-chymotrypsin biodegradation study showed that the crystalline structure of silk fibroin Silk I materials is enzymatically degradable with a much lower rate compared to uncrystallized silk materials. The crystalline structure of Silk I materials demonstrate a good long-term stability, endurance to alcohol sterilization without structural changes, and can be applied to many emerging fields, such as biomedical materials, sustainable materials, and biosensors.     

Preparation of insoluble fibroin/collagen films without methanol treatment and the increase of its flexibility and cytocompatibility

It is still a critical challenge to increase the flexibility of regenerated fibroin materials in dry and near dry states. In this study, a novel biocompatible and water‐stable film composed of fibroin and collagen was successfully prepared from aqueous fibroin solution without methanol treatment. The result of contact angle measurement indicates that hydrophilicity is evidently increased when collagen was added to fibroin film. The elongation at break in wet state is also increased because of the blending of collagen, which implied the improvement of flexibility. More importantly, the blend films containing 20% collagen become flexible when placed at above 65% humidity in atmosphere. It means that the blend films could be fabricated to different conformations easily through adjusting humidity in atmosphere. HepG2 cells were cultured on fibroin and fibroin/collagen films to investigate the cytocompatibility of these films. Scanning electron microscopy and MTT analysis demonstrated that the adding of collagen evidently improved HepG2 proliferation in over 10 days culture. The excellent cytocompatibility, the flexibility in the near dry state as well as the green preparation process of fibroin/collagen blend films make them become the promising biomaterials for different medical applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

SEDS工艺制备丝素纳米颗粒及其表征

以丝素蛋白为原料,以六氟异丙醇为溶剂,采用超临界流体强制分散溶液（SEDS）工艺制备了丝素纳米颗粒。单因素实验考察了压力、溶液浓度、溶液流速和CO2流速等因素对丝素纳米颗粒平均粒径分布的影响,并通过Zeta电位、HS-GC、FTIR、XRD和DSC等技术手段对制备的丝素纳米颗粒进行了表征。动态激光光散射仪检测结果表明：随压力、溶液浓度和流速的增大,丝素纳米颗粒平均粒径增大;随CO2流速的增大,丝素纳米颗粒平均粒径减小,最小达到298nm。丝素纳米颗粒Zeta电位为?39mV。HS-GC表明丝素纳米颗粒有机溶剂残留量为20μg/L。FTIR表明经SEDS工艺处理后丝素化学结构和官能团不会发生变化。XRD和DSC显示经SEDS工艺处理后丝素内部分子结构发生重排,由无规则卷曲向β折叠转换。     

A Fast and Reliable Process to Fabricate Regenerated Silk Fibroin Solution from Degummed Silk in 4 Hours

Silk fibroin has a high potential for use in several approaches for technological and biomedical applications. However, industrial production has been difficult to date due to the lengthy manufacturing process. Thus, this work investigates a novel procedure for the isolation of non-degraded regenerated silk fibroin that significantly reduces the processing time from 52 h for the standard methods to only 4 h. The replacement of the standard degumming protocol by repeated short-term microwave treatments enabled the generation of non-degraded degummed silk fibroin. Subsequently, a ZnCl₂ solution was used to completely solubilize the degummed fibroin at only 45 °C with an incubation time of only 1 h. Desalting was performed by gel filtration. Based on these modifications, it was possible to generate a cytocompatible aqueous silk fibroin solution from degummed silk within only 4 h, thus shortening the total process time by 48 h without degrading the quality of the isolated silk fibroin solution.     

棉织物丝素/TiO_2生态功能整理

用丝素蛋白整理棉织物,研究丝素蛋白降解时间及浓度对整理后棉织物性能的影响,确定最佳的丝素降解时间和浓度。在此基础上与TiO2复配,研究整理剂中TiO2含量对棉织物性能和结构的影响。结果表明:最佳丝素蛋白降解时间为120min,丝素浓度(质量分数)为1.63%;此时将丝素与TiO2复配,当TiO2质量分数为0.35%时,可使织物折皱回复角比纯丝素整理提高8.68%,紫外防护系数达到42.9,抗紫外性能达到二级。X射线衍射分析表明,丝素蛋白整理可降低棉纤维的结晶度,并使棉纤维由纤维素Ⅰ向纤维素Ⅱ转变,而TiO2整理可提高棉纤维的结晶度。