聚乳酸组织工程支架表面涂覆钙磷盐的工艺研究

提出了以聚乳酸/钙磷盐/胶原的骨组织工程支架快速成形制造的材料系统,对比了两种在聚乳酸(PLA)表面涂覆钙磷盐的工艺。一种是将聚乳酸组织工程支架浸泡在模拟体液中采用平衡反应法沉积钙磷盐;另一种是在聚乳酸薄膜上采用非平衡反应法沉积钙磷盐;系统地研究了沉积时间和沉积量、钙磷摩尔比和相结构演变的关系;通过控制反应时间和调整反应物配比获得磷酸四钙(TetCP)-PLA和无定形磷酸钙(ACP)-PLA等材料组合;并对所获得的复合材料进行生物相容性试验。对比试验证明细胞在材料表面生长良好,采用两种方法涂覆钙磷盐均改进了聚乳酸的生物相容性。

混杂结构聚乳酸/钙磷盐/胶原骨支架的表面处理研究(英文)

目的:将聚乳酸/钙磷盐/胶原复合材料作为制造骨组织工程支架的材料。方法:采用碱式反应法和共混法获得两种胶原/钙磷盐复合材料,然后通过真空吸附法在聚乳酸/磷酸三钙的支架表面沉积胶原,又通过碱式反应法沉积钙磷盐。结果:观测碱式反应法合成胶原-钙磷盐复合材料:胶原交联纤维束间形成薄膜状粘连。共混法获得胶原-钙磷盐复合材料显示:钙磷盐和胶原海绵紧密结合。快速成形工艺获得混杂结构支架可见:最后用碱式反应法合成的片状钙磷盐颗粒沉积在胶原海绵的表面。结论:此法获得了具有混杂结构的支架,可以应用于骨的修复。

聚乳酸/钙磷盐/胶原骨组织工程支架混杂结构的研究

首先采用碱式反应法和共混法获得两种胶原 /钙磷盐复合材料 ,然后通过真空吸附法在聚乳酸 /磷酸三钙的骨组织工程支架表面沉积胶原 ,又通过碱式反应法沉积钙磷盐 ,从而获得了具有混杂结构的支架。对材料形态的观察表明 ,胶原贴附在孔隙中 ,钙磷盐沉积在胶原上。

微图案化钙磷盐膜层的电化学构筑及其生物性能

基于表面分子自组装和光催化转印技术,在TiO2膜层表面获得超亲/超疏水阵列微图案模板,结合电化学沉积技术,成功制备了微图案化钙磷盐膜(CaP)层.扫描电子显微镜(SEM)和电子探针分析(EPMA)结果表明,通过超亲/超疏水阵列微图案模板可构筑高空间分辨的微图案化钙磷盐膜层.微图案化钙磷盐膜层的体外MG-63细胞培养证实,细胞对钙磷盐膜层微单元有强烈的选择性粘附作用,从而可望控制细胞在微单元中的贴壁生长,实现高通量评价细胞行为.

三种快速成型制作的聚酯/钙磷盐人工骨修复兔桡骨缺损的实验研究

目的 检验3种聚酯/钙磷盐植骨材料修复兔桡骨缺损的效果,筛选理想的组织工程用生长因子载体。方法 分别采用复合牛骨形态发生蛋白(bBMP)及单纯快速成型工艺制作的3种聚酯/钙磷盐载体材料修复兔桡骨15mm缺损,通过量化评价、影像学、组织学、材料降解及骨密度评价3种聚酯/钙磷盐载体材料修复兔桡骨缺损的效果。结果 12周时各材料实验组骨缺损均愈合,各检测指标同对照组比较差异均有统计学意义,空白对照组骨缺损未愈合,以聚乳酸聚羟基乙酸共聚物/磷酸三钙(PLGA/TCP)材料实验组修复效果最好,聚消旋乳酸/磷酸三钙(PDLLA/TCP)材料实验组次之,最后为聚左旋乳酸/磷酸三钙(PLLA/TCP)材料实验组。结论 3种聚酯/钙磷盐材料制作的仿生活性人工骨皆可以修复兔15mm长骨骨缺损,其中以PLGA/TCP材料效果最为理想。

聚酯/钙磷盐植骨材料的细胞生物相容性

骨缺损修复一直是骨科领域的难题之一。而利用骨组织工程的方法修复骨缺损被认为是最有前途的手段。作为骨组织工程细胞载体材料需要良好的组织及细胞相容性，我们采用骨髓基质细胞检测聚酯／钙磷盐支架与组织工程种子细胞的相容性，试图寻找一种有潜力的骨移植及细胞组织工程细胞载体材料。

聚酯／钙磷盐植骨材料的细胞生物相容性

骨缺损修复一直是骨科领域的难题之一，而利用骨组织工程的方法修复骨缺损被认为是最有前途的手段。作为骨组织工程细胞载体材料需要良好的组织及细胞相容性，我们采用骨髓基质细胞检测聚酯／钙磷盐支架与组织工程种子细胞的相容性，试图寻找一种有潜力的骨移植及细胞组织工程细胞载体材料。

化学沉淀法处理不同浓度含磷废水

针对总磷浓度分别为2mg/L、20mg/L以及200mg/L的含磷废水,以CaCl2、FeCl3、Al2(SO4)3·18H2O作为除磷剂,在不同投药量、不同反应pH下对三种浓度废水进行除磷处理,探索其最佳反应参数。研究表明,三种除磷剂的投药量与总磷去除效果均呈正相关,若在达到最适投加比后进一步加大药剂量,则除磷收益会逐渐降低。三种除磷剂的最佳反应pH明显不同,原因在于不同条件下磷酸根的形态差异,以及磷酸根与除磷剂所形成络合物的溶解性不同。此外,废水总磷浓度对除磷剂投加量影响显著,废水中总磷浓度越低,除磷剂对于总磷的去除效率越低,需要的单位除磷剂投加量也会相应增多。

金属加工含磷废水的处理及水回用研究

以某金属加工企业废水为研究对象,考察了含磷废水回用工艺,即钙盐除磷和过滤的工艺条件,结果表明,废水pH调至10.0～10.5,CaC12投加浓度为700～800 mg/L,PAC投加浓度为150～200 mg/L,除磷系统沉淀出水TP=3～5 mg/L,去除率可达95％,同时去除了废水中少量的重金属离子.沉淀池出水经过砂滤和炭滤后TP＜3 mg/L,Zn2＋＜1 mg/L,Ni2＋＜0.8 mg/L,水质优于回用水指标直接回用,减少了排放.

镁锌合金骨螺钉表面防降解改性涂层的制备与性能

采用电化学沉积方法在镁锌合金骨螺钉表面制备了无氟和含氟(FHA)的钙磷盐防降解涂层,并在模拟人体体液中进行体外降解试验,采用扫描电镜和X射线衍射仪等分析了降解前后涂层的形貌与晶体结构。结果表明:无氟涂层为丝状和块状结构,而含氟涂层为柱状结构;无氟和FHA钙磷盐涂层都可以有效减缓镁合金在模拟人体体液中的腐蚀,前者比后者的效果更佳;FHA涂层不易溶解,但与外形复杂的螺钉结合不牢,且其质脆,浸泡过程中易于脱落;无氟涂层则能保持完整性,可以对骨螺钉起到更好的保护作用。

Influence of solution temperature on corrosion resistance of Zn-Ca phosphate conversion coating on biomedical Mg-Li-Ca alloys

The influence of phosphating bath at different temperatures on the formation and corrosion property of calcium-modified zinc phosphate conversion coating （Zn-Ca-P coating） on Mg-Li-Ca alloy was investigated. The morphologies, elemental distribution and chemical structures of the coatings were examined via SEM, EPMA, EDS, XRD and FT-IR. The corrosion resistance was assessed by hydrogen evolution, potentiodynamic polarization and EIS. The results show that the coating is composed of single element Zn and ZnO at below 45 ℃;whereas the coatings are predominantly characterized by Zn3（PO4）2·4H2O and small amount of element zinc and ZnO at above 50 ℃. Mg-Li-Ca alloy with Zn-Ca-P coatings prepared at 55 ℃ has the highest corrosion resistance. However, the hydrogen evolution rates of the coatings obtained at 40-50 ℃ is accelerated due to the galvanic corrosion between the imperfection of the single element Zn coating and the Mg substrate.

Corrosion resistance of cerium-doped zinc calcium phosphate chemical conversion coatings on AZ31 magnesium alloy

Zinc calcium phosphate （Zn-Ca-P） coating and cerium-doped zinc calcium phosphate （Zn-Ca-Ce-P） coating were prepared on AZ31 magnesium alloy. The chemical compositions, morphologies and corrosion resistance of coatings were investigated through energy-dispersive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, electron probe micro-analysis （EPMA） and scanning electron microscopy （SEM） together with hydrogen volumetric and electrochemical tests. The results indicate that both coatings predominately contain crystalline hopeite （Zn3（PO4）2·4H2O）, Mg3（PO4）2 and Ca3（PO4）2, and traces of non-crystalline MgF2 and CaF2. The Zn-Ca-Ce-P coating is more compact than the Zn-Ca-P coating due to the formation of CePO4, and displays better corrosion resistance than the Zn-Ca-P coating. Both coatings protect the AZ31 Mg substrate only during an initial immersion period. The micro-galvanic corrosion between the coatings and their substrates leads to an increase of hydrogen evolution rate （HER） with extending the immersion time. The addition of Ce promotes the homogenous distribution of Ca and formation of hopeite. The Zn-Ca-Ce-P coating has the potential for the primer coating on magnesium alloys.

Leaching kinetics of calcium molybdate with hydrochloric acid in presence of phosphoric acid

Calcium molybdate(CaMoO4)is the main component of powellite and is a predominant intermediate in the pyrometallurgical and hydrometallurgical process of molybdenum.The extraction of Mo from CaMoO4 by a combination of phosphoric acid and hydrochloric acid was investigated.For further understanding of the leaching mechanism,the effects of five key factors were studied to describe the leaching kinetics.The results indicated that the dissolution rate of CaMoO4 was independent of the stirring speed.Mo extraction significantly increased with increasing HCl concentration and temperature,but decreased with increasing particle size.A shrinking core model with surface chemical reaction was found to withstand the dissolution of CaMoO4.The apparent activation energy was calculated to be 70.879 kJ/mol,and a semi-empirical equation was derived for the rate of reaction.

Synthesis of phosphate-embedded calcium alginate beads for Pb(Ⅱ) and Cd(Ⅱ) sorption and immobilization in aqueous solutions

The phosphate-embedded calcium alginate beads were successfully synthesized based on sodium alginate, calcium dihydrogen phosphate and sodium hydrogen carbonate. Scanning electron microscopy, Fourier transformed infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were conducted to characterize the morphology and structure of the phosphate-embedded calcium alginate beads. The effects of pH and the initial concentration of the metal ions on Pb(II) and Cd(II) sorption by the beads were investigated. The optimal pH values for Pb(II) and Cd(II) sorption are 4.0 and 5.5, respectively. The optimal initial concentrations of Pb(II) and Cd(II) are 200 mg/L and 25 mg/L, correspondingly, and the removal efficiencies are 94.2% and 80%,respectively. The sorption mechanism is that the heavy metal ions accessed the beads firstly due to the large surface area, combinedwith OH?, and then precipitated with phosphate radical, which was proven by FTIR and XRD. The sorption of Pb(II) and Cd(II) isfitted to Langmuir isotherm model with R2 values of 0.9957 and 0.988, respectively. The sorption capacities of Pb(II) and Cd(II) are263.16 mg/g and 82.64 mg/g, respectively. The results indicate that the phosphate-embedded calcium alginate beads could be appliedto treating Pb(II)/Cd(II)-containing wastewater and it could be implied that the synthesized beads also could be used as a kind of soil ameliorant for remediation of the heavy metal contaminated paddy soil.

Alkaline treatment kinetics of calcium phosphate by piezoelectric quartz crystal impedance

Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance （PQCI） technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） and X-ray diffraction （XRD）, respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite （HA） is composed of three stages： （1） acidic calcium phosphate dissolution; （2） phase transformation; and （3） HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance （C8）-time curves.

Characterization of tricalcium phosphate solubilization by Stenotrophomonas maltophilia YC isolated from phosphate mines

The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium.

Inositol 1,4,5-trisphosphate 3-kinases:functions and regulations

Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K) plays an important role in signal transduction in animal cellsby phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4). Both IP3 and IP4 arecritical second messengers which regulate calcium (Ca2+) homeostasis. Mammalian IP3Ks are involved in many biologicalprocesses, including brain development, memory, learning and so on. It is widely reported that Ca2+ is a canonicalsecond messenger in higher plants. Therefore, plant IP3K should also play a crucial role in plant development. Recently,we reported the identification of plant IP3K gene (AtIpk2β/AtIP3K) from Arabidopsis thaliana and its characterization.Here, we summarize the molecular cloning, biochemical properties and biological functions of IP3Ks from animal, yeastand plant. This review also discusses potential functions of IP3Ks in signaling crosstalk, inositol phosphate metabolism,gene transcriptional control and so on.

Preparation and Improvation of Nanophase Artificial Bone Composite Scaffold and Relevant Study on Properties

Objective：To prepare nanophase artificial bone composite scaffold based on bionics theory, and probe into how different content ratio between collagen and inorganic part as well as different molecular weight of conglutinant agent influence microstrueture and properties of the scaffold. Methods： Lead calcic inorganic molecules to deposite onto self-assembled collagen template during coprecipitation under certain reactive conditions such as content ratio and pH value of environment, and then nanophase collagen/calcic salt is obtained. In order to improve the mechanical properties, poly lactic acid （PLLA） which has stable equal properties and controllable biodegradable activities is chosen as conglutinant agent, and then the aimed artificial bone scaffold （nanophase collagen/calcic salt/PLLA composite） is accomplished. After preparation liquid displacement method with isoproanol alcohol, scanning electron microscopic （SEM） , transmission electron microscope （TEM）, fourier transform infrared spectrometry （FTIR）, mechanical testing system are performed to test porosity and density, morphology, conformation, composition and mechanical property, respectively. Results：The artificial synthesized bone composite scaffold is mainly composed of collagen and calcium phosphate partly displaced with B-type carbonate. The crystallinity is low, and the crystal size reaches nanometer which is similar to natural bone. PLLA used effectively improves the mechanical property which can reach at the floor level of cancellous standard, and develops three-dimensional-porous structure with high porosity of 80%. According to the comparison it can be seen that content ratio between collagen and calcic inorganic salt as well as addition of conglutinant PLLA all have an effect on microstructure of the synthesized scaffold, additionally molecular weight of PLLA has an effect on mechanical properties. Conclusion ：The nanophase artificial bone composite scaffold synthesized by biomimetic process is one of the most promising optimal materials for clinical application no matter how judged from structure, composition and property. The various factors influencing the scaffold discussed in this article may indicate some useful modification ways according to the actual utility in the near future.

The Effect of Calcium Chloride on the Microbiological Characteristics of Fermented Chile Pepper （Capsicum annuum cv. Mesilla Cayenne） Mash

Fermented chile pepper mash （Capsicum annuum cv. Mesilla Cayenne） is a major industrial food product in New Mexico. The fermentation of chile pepper mash depends on temperature, acidity, salt concentration, dissolved air, available carbohydrates and enzymes. The objective of this study was to evaluate the effects of the addition of calcium chloride （CaCI2） on the microbial characteristics of the pepper mash fermentation. Nine five gallon buckets were prepared with pepper that had been washed and ground by the manufacturer, each with 15% sodium chloride added. The buckets were allotted randomly to 1 of 3 treatments. The treatments included no CaCl2, 0.2% CaCl2 and 0.4% CaCl2 added to the pepper mash. Samples were stored at room temperature and sampled over a 3 months period to examine changes in the microflora. Chile mash samples were serially diluted in butterfield＇s phosphate buffer for microbial enumeration. Aerobic plate counts were conducted by pour plating with an overlay. Petrifilms were used for E. coil/coliform counts and Enterobacteriaceae. Yeasts and molds were surface plated on Rose Bengal Chloramphenicol agar while streptococci and lactobacilli were plated onto M17 and acidified MRS respectively. Aerobic plate counts, coliforms, E. coli, Enterobacteriaceae, yeast, mold, lactobacilli, and streptococci were not affected by CaCl2 level. The addition of 0.4% CaCl2 was found to have no effect on the chile pepper mash fermentation.

骨组织工程快速成型支架改性的相关研究

目的探讨胶原杂化及磷灰石表面沉积改性后的聚乳酸一羟基乙酸共聚物／β-磷酸三钙（PLGA／β—TCP）作为快速成型支架应用于骨组织工程的可行性。方法使用骨髓基质干细胞对胶原杂化及磷灰石表面沉积改性后的PLGA／β-TCP的生物相容性进行评估，通过扫描电镜观察改性后材料的表面特性及细胞与材料复合的形态学特征；细胞与材料复合后的繁殖与分化能力分别使用细胞计数及碱性磷酸酶定量方法进行评估。结果通过对亲水性、细胞增殖能力及碱性磷酸酶测定证实改性后的PLGA／β-TCP快速成型支架较单纯材料其亲水性及生物相容性有明显提高（P〈0．05）。结论胶原杂化及磷灰石表面沉积改性后的PLGA／β—TCP快速成型支架可作为三维支架应用于骨组织工程。