Facile conjugation of heparin onto titanium surfaces via dopamine inspired coatings for improving blood compatibility

Immobilization of heparin on biomaterials surface has been proven to be an effective strategy for preventing thrombus formation. However, the procedures of most immobilization methods（physical adsorption, covalent linkage, electrostatic interaction） are complicated and time-consuming. In the present study, heparin with various concentrations immobilized on a titanium（Ti） substrate via polydopamine layer for improving blood compatibility was investigated. Water contact angle measurement showed that the immobilization of heparin resulted in an increase of the hydrophilicity. X-ray photoelectron spectroscopy（XPS） and Toluidine Blue O（TBO） tests displayed that the heparin molecules were successfully immobilized on Ti surface. The evaluations of blood compatibility（hemolysis rate, APTT, platelet adhesion and activation, fibrinogen conformational change） showed that the immobilization of heparin decreased hemolysis rate, prolonged blood coagulation time, reduced platelets adhesion and activation, and induced less fibrinogen conformational change. Moreover, a significant inhibition of blood coagulation and platelet adhesion was obtained when the heparin concentration was higher than 5 mg/mL, indicating that only with a certain surface densities could heparin perform its anticoagulant properties well. The results suggest that the immobilization of heparin via polydopamine layer can confer excellent antithrombotic properties, and the heparin immobilization method via polydopamine layer provides an alternative approach for other biomolecules immobilization on biomaterials surface. Thus it is envisaged that this method will be potentially useful for the surface modifi cation of blood-contacting biomaterials.     

Immobilization of RGD peptide onto the surface of apatite-wollastonite ceramic for enhanced osteoblast adhesion and bone regeneration

The arginine-glycine-aspartic （RGD） acid peptide was grafted to the surface of apatitewollastonite （AW） ceramic in an effort to improve its cell adhesion, proliferation and osteoinduction. RGD peptide was covalently immobilized onto the surface of AW ceramic via the synthetic cross linker AA.PTS-E and 1-ethyl-3-（3-dimethylaminopropyl）carbodiimide （EDC）. The modified surfaces were characterized by attenuated total reflectance Fourier transform infrared spectroscopy （ATR-FTIR） and X-ray photoelectron spectroscopy （XPS）. The chemical analysis indicated that RGD peptide had been immobilized onto the AW surface successfully. The growth of osteoblast-like cells （MG63） showed that modifying the AW surface with RGD peptide enhanced the cell adhesion and proliferation. And the histological evaluation of RGD-AW showed that the bone regeneration and remodeling process were significantly enhanced compared to the original AW ceramics after 2, 4 and 8 weeks implantation in rabbit＇s femoral condyles.     

<Emphasis Type="Italic">In vitro</Emphasis> blood compatibility of polyethylene terephthalate with covalently bounded hirudin on surface

Polyethylene terephthalate (PET,Dacron) was modified by surface immobilization of hirudin with glutaraldehyde(GA) as coupling reagent to improve the blood compatibility.Hirudin-immobilized PETs were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements.The blood compatibility of the PETs was evaluated by platelet adhesion evaluation and fibrinogen conformational change measurements in vitro.The results showed the decrease of platelet adhesion and activation on hirudin-immobilized PET with increasing of glutaraldehyde concentration.Fibrinogen experiment showed that fibrinogen adherence and conformational changes of PET-HRD were less than those of untreated PET,which made the materials difficult to form thrombus.The proper reason of blood compatibility improvement was low interface tension between hirudin-immobilized PETs and blood,as well as blood proteins,and low ratio of dispersive/polar component of the surface energy(γsd/γsp) and high hydrophilicity.     

巯基自组装修饰恒电位共价键合法固定基因电化学传感器的制备与表征

以金电极为基体电极,采用巯基乙醇自组装法制备了巯基乙醇自组装膜修饰电极,再以碳二亚胺为交联剂用控制电位共价键合法将DNA固定在巯基乙醇单分子层上形成了基因修饰电极。以亚甲蓝为电化学杂交指示剂,采用循环伏安法、微分脉冲伏安法等电化学方法对基因电化学传感器进行了表征。结果表明,该方法能够将DNA稳定地固定于电极表面,可用于制备自组装修饰基因电化学传感器。     

聚丙烯酸酯乳液改性水性聚氨酯性能的研究

采用4,4’-二苯基甲烷二异氰酸酯(MDI)合成了聚酯型阴离子水性聚氨酯(WPU)乳液,并与聚丙烯酸酯(PA)乳液共混制备出改性水性聚氨酯乳液,研究不同含量的PA对水性聚氨酯的结构和性能的影响。结果表明:复合乳液中PU和PA的相容性较好,共混改性后的PU/PA膜比纯的水性聚氨酯膜的耐水性能和耐热性能有明显的提高。     

Characterization of Ti-Cu Films Deposited by HPPMS and Effect on NO Catalytic Release and Platelet Adhesion Behavior

Ti-Cu films with different Cu concentrations were fabricated by high-power pulsed magnetron sputtering(HPPMS) to release copper ions and catalyze NO to improve the blood compatibility. The Cu concentrations of films were 25.7 at% and 68.8 at%. Pure Ti films were also fabricated. Copper release, catalytic release of nitric oxide(NO), and blood platelet adhesion of Ti-Cu films were studied. Ti-Cu films released copper ions in PBS solution and more Cu ions were released from films with 68.8 at% Cu. Ti-Cu films had excellent ability of catalytical decomposition of exogenous donor S-nitroso-N-acetyl-DL-penicillamine(SNAP) and as a result, nitric oxide(NO) was generated. The NO generation catalyzed by Ti-Cu films was significantly higher than that by pure Ti films. This was more eminent in the Ti-Cu films with 68.8 at% Cu. The platelet adhesion and activation of Ti-Cu films were significantly inhibited compared to that of pure Ti films in the presence of SNAP. The Ti-Cu film fabricated by HPPMS showed the ability of releasing Cu ions to catalyze SNAP to generate NO to inhibit platelet adhesion and activation.     

Compatibility and Properties of Biodegradable Blend Films with Gelatin and Poly（vinyl alcohol）

The blend films with gelatin and poly（vinyl alcohol） （PVA） were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform infrared spectroscopy （FTIR）, x-ray diffraction （XRD）, thermogravimetry analysis （TG）, and differential scanning calorimetry （DSC） were employed to characterize the resultant blend films. According to optic result, the opacity of the blend film at the ratio of 20/80 （w/w, Gel to PVA） was the lowest, indicating the best compatibility between Gel and PVA at the ratio. The results oflR, XRD, DSC, and TG revealed an intensive interaction and good compatibility between them in the blend film at the ratio. The mechanical properties and solubility showed that PVA content in the blend films obviously affected the elongation at break and solubility. The mechanical properties and water resistance of gelatin film may be improved by the introduetion of PVA.     

Surface modification of silk fibroin films with zwitterionic phosphobetaine to improve the hemocompatibility

Zwitterionic phosphobetaine bearing a hydroxyl and a zwitterionic group, 8-hydroxy-2-octyl phosphorylcholine (HOPC), was synthesized and constructed to the surface of silk fibroin(SF) films in order to improve the hemocompatibility of fibroin films by a an isocyanate head group. The surface characteristics of the modified films were measured by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and electron spectroscopy for chemical analysis (ESCA), displaying the successful immobilization of Zwitterionic phosphobetaine on the surface of these fibroin films. Moreover, the further platelet adhesion test in platelets rich plasma (PRP) of human beings showed the zwitterionic phosphobetaine led mainly to good nonthrombogenicity. The experimental results indicated a reasonable approach to improve the blood compatibility of fibroin films.     

偶联剂对PVC/纸粉复合材料性能的影响

采用硅烷偶联剂、铝酸酯偶联剂和钛酸酯偶联剂对纸粉进行表面处理,研究了纸粉填充PVC复合材料的力学性能和热学性能。研究结果表明,钛酸酯偶联剂可以较好地改善纸粉与PVC基体的相容性,从而显著提高复合材料的力学性能。冲击断面扫描电镜分析表明,偶联剂改善了纸粉与基体树脂的相容性。     

溶胶-凝胶法制备聚酰亚胺/二氧化硅纳米杂化薄膜

采用溶胶-凝胶体系,通过甲基三乙氧基硅烷在聚酰胺酸溶液中水解和缩聚原位产生二氧化硅纳米粒子,制备出了聚酰亚胺／二氧化硅纳米杂化薄膜,并讨论了不同质量分数的二氧化硅对薄膜性能的影响．为了增强两相之间的结合力和相容性,在实验中加入了一定量的偶联剂,对制备成的薄膜采用红外光谱、原子力显微镜等进行结构表征,并讨论了结构与性能的关系,实验证明,纳米杂化材料的性质不但与每一组分的性质有关,还与组成材料的两相之间相的形态和界面性质紧密相关,偶联剂对聚酰亚胺／二氧化硅体系两相间的相容性、分散性具有改善作用;杂化薄膜的电性能随二氧化硅的质量分数增加有所提高。     

直流PCVD TiN膜针孔率的研究

用铁氰化钾贴纸法研究了PCVD(Plasma CVD)TiN膜中针孔率与沉积温度、样品表面粗糙度和膜厚度的关系。发现TiN膜薄时,针孔率高,针孔直径多数在1～3μm;TiN膜厚时,针孔急剧减少,针孔直径均在3.5～6μm,表明小直径的针孔在TiN生长中逐渐消失。TiN膜厚达到8～10μm时,仍有针孔存在。扫描电镜观察表明:形成针孔的主要原因是表面存在杂质(或污物)和孔洞缺陷。     

聚乙烯亚胺肝素涂层改性聚氯乙烯与表征

为了改善医用聚氯乙烯材料的生物相容性和抗凝血性,采用新型肝素涂层技术对医用聚氯乙烯材料表面进行改性,研究了涂层中肝素的稳定性.利用聚乙烯亚胺-肝素结合的方法,将肝素涂层固定在医用聚氯乙烯材料表面.使用傅里叶红外光谱仪对其进行测试,绘制肝素钠和聚乙烯亚胺 肝素复合物的标准浓度曲线,通过分光光度法测定了医用聚氯乙烯材料表面肝素的含量,并计算肝素的脱落率.实验表明,在聚氯乙烯表面肝素与聚乙烯亚胺通过阴阳离子相互作用而结合,而且在聚氯乙烯面的肝素含量为944.1 μg/cm2,浸泡在生理盐水中700 h后,肝素的释放速率先快后慢,最终趋于稳定,其表面肝素脱落量仅为0.78%.这说明聚乙烯亚胺-肝素涂层改性的聚氯乙烯材料具有良好的肝素稳定性与极低的脱落率.     

超声促进钛酸酯偶联剂与CaCO_3表面相互作用研究

使用改性剂对重钙表面进行改性是增强其表面的亲油性,改善它在有机高聚物中的相容性和分散性,以获得更好性能的高聚物重钙复合材料。采用异丙醇溶解的改性剂钛酸酯偶联剂NDZ-311分别在超声与搅拌下对超细重质CaCO3进行湿法表面改性,测试了改性重钙活化指数和它在液体石蜡中的分散稳定性。用红外光谱（IR）、X-射线光电子能谱（XPS）等技术对改性重钙进行表征。结果表明,钛酸酯偶联剂NDZ-311用量≤1.0%时,超声分散作用明显地提高了改性重钙的活化指数与其在石蜡中的分散稳定性;随着偶联剂用量增加,超声分散与搅拌分散方法改性对改性后样品性能影响差距减小,形成单层包覆所需改性剂用量接近,约为2.5%。超声分散方法明显地促进了钛酸酯偶联剂NDZ-311与CaCO3表面的化学键合。     

阴离子型聚氨酯对丝素蛋白膜性能的影响

通过水分散阴离子型聚氨酯和丝素共混的方法，制备了丝素／聚氨酯(SF／PU)共混膜。借助SEM、Raman光谱和X-射线衍射法分析了不同配比共混膜的结构。结果表明：共混膜为非均相体系；膜的结构、力学性能和透气性均与膜中两组分的相对含量有关，随着聚氨酯的加入，共混膜的柔韧性得到提高，它能够克服纯丝素膜刚而脆的弱点。最后，对用共混液整理的真丝织物的湿态回复角、透气性等物理性能作了初步分析。     

葡萄糖氧化酶在氨等离子体改性膜上的固定化

利用等离子体技术使聚丙烯膜表面氨基化，并以此膜为葡萄糖氧化酶的固定化载体．运用光电子能谱法确定了氨等离子体改性处理引起的膜表面化学结构的变化．讨论了氨等离子体处理时，单体流量、处理时间和放电功率等参数对改性膜固定化酶活力的影响     

Preparation of immobilized <Emphasis Type="Italic">ɛ</Emphasis>-polylysine PET nonwoven fabrics and antibacterial activity evaluation

A novel antibacterial material (L-PET) was prepared by immobilizing ε-polylysine on polyethylene terephthalate (PET) nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modification procedure where carboxyl groups were prepared on the PET surface, a coupling agent was grafted, and the ε-polylysine was immobilized. Scanning electron microscopy (SEM) was used to analyze the surface morphology of the fabrics, while the toluidine blue method and X-ray photoelectron spectroscopy (XPS) were used to evaluate the grafting densities. The antibacterial activities of the L-PET were investigated by using the shaking-flask method. The electron micrographs showed that the surface of the blank PET and the modified fabrics did not change. The results of XPS analysis confirmed that ε-polylysine was successfully grafted onto the surface of PET. The results of the antibacterial experiments showed that L-PET fabrics had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, and that L-PET fabrics were stable in storage for at least two years.     

智能调温聚氨酯固-固相变材料的研究

采用化学改性的方法,将不同含量,不同分子量的聚乙二醇(PEG)接枝到以聚醚型的聚氨酯(PU)上,制备出一种新型的固-固相变材料。并通过红外光谱法(IR),示差扫描量热法(DSC)来研究合成材料的结构与相变行为。结果表明,PEG成功地接枝在高分子链PU上,且具有较好的相变焓,适合的相变温度,并当PEG分子量相同时,随着PEG含量的增加,相变材料相变焓增大,热切热稳定性有明显改善,当PEG含量相同,PEG分子量在600～2000时,随着分子量的增加,材料的相变焓增大。     

Surface modification of fire-retardant asphalt with silane coupling agent

The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced.The optimum silane dosage was determined,and the structure and properties of the asphalt fire-retardant before and after the surface modification were characterized by infrared spectrum and thermo gravimetric analysis.The dispersion effect of asphalt fire-retardant was studied.The influence of the surface modification on the hydrophilicity and lipophilicity of the asphalt fire-retardant was analyzed.The experimental results showed that there were physical and chemical interactions between the silane coupling agent and the asphalt fire-retardant,which reduced the surface polarity of the asphalt fire retardant.The optimum silane coupling agent dosage was 0.95% of the asphalt fire retardant.The surface modification improved the thermal stability,dispersibility and lipophilicity of the asphalt fire retardant,which enhanced the compatibility between asphalt fire retardant and asphalt.     

Effect of Adding Microwave Absorber on Structures and Properties of Hypercoal-Based Activated Carbons

Using lignite-based hypercoal as raw material,KOH as activator and CuO as microwave absorber,we prepared hypercoal-based activated carbons by microwave-assisted activation.The pore structure and the electrochemical performance of the activated carbons were tested,and the effects of adding CuO in the activation reaction process were also investigated.The activated carbons prepared were characterized by nitrogen adsorption-desorption,X-ray diffraction (XRD) and scanning electron microscopy (SEM).The specific surface area and mesoporous ratio of the hypercoal-based activated carbon are 1 257 m~2/g and 55.4%,respectively.When the activated carbons are used as the electrode materials,the specific capacitance reaches 309 F/g in 3 M KOH electrolyte.In comparison with those prepared without CuO absorber,the specific capacitance increases by 11.6%.It was proved that the addition of microwave absorber in microwave-assisted activation was a low-cost method for rapidly preparing activated carbon,and it could effectively promote the development of the pore structure and improve its electrochemical performance.     

Antithrombogenic investigation and biological behavior of cultured human umbilical vein endothelial cells on Ti-O film

The cardiovascular disease is the number one cause of morbidity and mortality in the western world. Each year, about 17 million patients in the world die of heart valve dis-ease, arteriosclerosis, etc. About 750 thousands patients is adding in China every year. A lot of new materials are used as artificial blood contacting biomaterials, but blood com-patible biomaterials have not yet been developed. Improving the hemocompatibility of blood contacting biomaterials has become a very important t…