纯钛表面TiN/Ag多层复合结构制备及生物学性能的评价

背景:在钛种植体表面建立一种能促进细胞早期黏附增殖、分化且无细胞毒性抑菌效果明显的界面至关重要。目的:在纯钛种植体材料表面制备Ti N/Ag多层复合结构涂层,分析其抗菌性能及对MC3T3-E1细胞生物学行为的影响。方法:采用酸蚀喷砂技术及多弧离子镀技术在光滑纯钛表面制备Ti N/Ag多层复合结构。取生长状态良好的MC3T3-E1细胞,分别接种于光滑钛片、酸蚀喷砂钛片及载Ti N/Ag多层复合结构钛片表面,接种后24 h,激光共聚焦显微镜观察细胞黏附及细胞活化情况,扫描电镜观察细胞生长形态;接种后24,48,72 h,CCK-8法检测细胞增殖及毒性分级。将金黄色葡萄球菌菌液分别滴加于光滑钛片、酸蚀喷砂钛片及载Ti N/Ag多层复合结构钛片表面,16 h后,激光共聚焦显微镜观察细菌生长情况。结果与结论:(1)激光共聚焦显微镜显示,光滑组细胞呈两极或三极的纺锤状结构,F-肌动蛋白和丝状伪足表达量较少;酸蚀喷砂组与载银涂层组细胞分散附着排布,方向不同,并形成大量丝状伪足,相互交织融合在一起,细胞铺展较充分,F-肌动蛋白明显高表达,肌动蛋白纤维较粗;(2)扫描电镜显示,光滑组细胞黏附与铺展不够充分;酸蚀喷砂组、载银涂层组细胞铺展黏附良好,铺展大,细胞状态较好;(3)CCK-8实验显示接种72 h后,载银涂层组细胞生长良好,增殖明显,细胞毒性为1级;(4)激光共聚焦显微镜显示,光滑组和酸蚀喷砂组钛片表面金黄色葡萄球菌生长良好,载银涂层组钛片表面细菌出现大面积死亡;(5)结果表明,Ti N/Ag多层复合结构涂层具有良好的细胞相容性及抗菌性能。

一种提升VBW的馈电补偿优化技术

VBW(视频带宽)是宽带发射机实时工作带宽能力的重要指标。提出一种提升VBW的馈电补偿优化技术。通过对发射机中功率放大器的记忆效应进行原理分析,提出VBW频率响应表征公式,并给出工程中电路改进方法。实测结果表明该技术能有效提升多载波发射机中功率放大器的VBW能力。

Study on the Surface Modification of Hydrophobic Polyacrylate Intraocular Lens

In this study, the polyacrylate intraocularr lens is irradiated by argon ion which can produce free radicals. In order to obtain better hydrophilic and lower platelets adhesion, monomer vinyl pyrrolidone (NVP) is grafted onto the hydrophobic polyacrylate intraocular lens surface in a certain reaction conditions. Specific changes in intraocular lens are detected by static contact angle (CA), scanning electron microscope (SEM) and light transmittance. The results show that this surface modification can greatly improve its hydrophilic character and surface formation.

Study on Preparation of Temperature-sensitive Injectable Hydrogel

To get a sort of new scaffold material for soft tissue reconstruction,we have prepared XLHA-PNIPAAm and XLHA-MC injectable hydrogels through blending crosslinked HA(XLHA) and two temperature-sensitive materials differed in degradation poly(N-isopropylacrylamide)(PNIPAAm) and methylcellulose(MC),respectively.We tested the injectablility,enzymatic biodegradability,temperature-sensitivity,structure cytotoxicity and hemolysis of the two injectable hydrogels.Our research has successfully obtained the preparation condition of XLHA-PNIPAAm injectable hydrogel,and verified that adding non-degradable material PNIPAAm can postpone the degradation of HA more effectively than degradable material MC.PNIPAAm prepared with 5 kGy dose radiation,MBAAm/NIPAAm(M/M)=0.015,monomer concentration=3% produced XLHA-PNIPAAm with slowest enzymatic biodegradability.DSC results showed that temperature-sensitivity of the XLHA-PNIPAAm was more stable than that of XLHA-MC.Two composite hydrogels were qualified in cytotoxicity and hemolysis tests and the biocompatibility of XLHA-PNIPAAm hydrogel showed better than XLHA-MC hydrogel.

NH_2 Ion Implantations Induced Superior Cell Attachment of Carbon Nanotubes

Objective: Cell and platelet attachment on the multiwalled carbon nanotubes (MWCNTs) were studied by ion implantation. Methods: NH2 ion implantation was performed at the energy of 30 keV with the fluence of 1×1016 ions/cm2 at room temperature. Results: The cell attachment tests showed interesting results in that the number of the platelets adhering on the surface of the MWCNTs was reduced significantly after NH2 ion implantation, whereas, mouse fibroblast cells (L929) cultured on NH2 ion implanted MWCNTs displayed higher cell-viability, proliferation, and stretching compared with MWCNTs. Conclusion: No appreciable change in the tensile strength and the optical transmittance of the implanted samples was observed. X-ray photoelectron spectroscopy(XPS) analysis showed that NH2 ion implantation caused the formation of new N-containing groups.

Preparation of Aminated Macroporous Polyvinyl Alcohol Resins and Evaluation for Bilirubin Adsorption

In the present study we prepared macroporous polyvinyl alcohol beads. A series of bilirubin adsorbents were generated by immobilization of eight amine agents to the beads as ligands. The adsorption of bilirubin was evaluated by in vitro static and dynamic adsorption tests. The results show that these adsorbents have excellent adsorption efficiency and capacity. Among the eight ligands, trimethylamine (TMA), triethylamine (TEA) and 1,6- hexanediamine(HDA) showed the highest adsorption capacity. The adsorption equilibrium can be achieved in half an hour, and the adsorption percentage of bilirubin was up to 80%. Static electricity and hydrophobic interaction played the main role in bilirubin adsorption, and the adsorption was found to match the monolayer model. The excellent adsorption of these adsorbents indicates their potential in clinical treatment.

Comparison on Hemocompatibility of MWCNTs and Hydroxyl Modificated MWCNTs

Objective: To study and compare the hemocompatibility of MWCNTs and hydroxyl modificated MWCNTs (MWCNTs-OH). Methods: MWCNTs and MWCNTs-OH were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, water contact angle assays, platelet-adhesion and hemolytic rate assays. Results: The results showed that the two MWCNTs had a similar surface topography and MWCNTs-OH were functionalized with hydroxyl groups on their surfaces. Water contact angle assays indicated that MWCNTs were hydrophobic materials, whereas MWCNTs-OH was hydrophilic. The platelet-adhesion assays displayed that the platelet-adhesion rate of MWCNTs-OH was much lower than MWCNTs. The hemolytic rate assays showed that the hemolytic rates of both MWCNTs were lower than the standard value of 5%. Conclusion: MWCNTs-OH shows superior anticoagulant capacity over MWCNTs. Both MWCNTs and MWCNTs-OH are nonhemolytic materials.

Study on Characteristics of Acellular Bovine Pericardium Crosslinked with Genipin

The study used a naturally occurring crosslinking reagent-genipin to chemically modify acellular bovine pericardium, prepare cardiac valve tissue engineering scaffold material,and evaluated genipin crosslinked acellular matrix of bovine pericardium by investigating the physical and chemical properties of the tissues, such as the surface properties, crosslinking characteristics, mechanical properties, resistance to enzymatic capacity in vitro, and hemolysis tests. The results showed that acellular bovine pericardium matrix crosslinked with genipin was strong hydrophilicity, high crosslinking index, and stable structure, which can maintain good mechanical properties. As a kind of scaffold material for valve tissue engineering, it has wide application prospect.

Comparison of Ceramide Production with PLC Irradiated by 810 nm LED and 808 nm Laser

Due to its major role in maintaining the water-retaining properties of the epidermis, ceramide is of great commercial potential in cosmetics and pharmaceuticals such as hair and skin care products. However, current synthetic approaches for ceramide are tedious and time-consuming for industrial applications. Therefore, it is desirable to find an alternative cost-efficient and highly-yield method for obtaining the valuable products. In present study, the potential of producing ceramide through enzymatic hydrolysis of sphingomyelin with enzyme irradiated by 808 nm light has been studied. With enzyme irradiated by 808 nm light, its activity can be enhanced and reaction speed can be increased significantly.

Requirements for Evaluation on Drug-medical Device

The administration of combination products in U.S.Food and Drug Administration(FDA)are analyzed and summarized in this paper.Furthermore,the technical evaluation on drug-medical device in the State Food and Drug Administration of China(SFDA)is also illustrated.Meanwhile,this paper discusses how to promote the development of drug-medical device in the administration and technical evaluation.

In vitro Studies on Binding and Release of Vascular Endothelial Growth Factor in Heparinized Bovine Pericardiums

Objective: To investigate binding and release of vascular endothelial growth factor (VEGF) and its effect on adhesion and proliferation of endothelial cells (ECs) in acellular fresh specimens of bovine pericardiums, which were modified by heparinization. Methods: Cross-linked acellular fresh specimens of bovine pericardiums were heparinized by three methods: (1) heparinized N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) treated acellular tissue samples; (2) heparinized poly(ethyleneimine) (PEI) treated acellular tissue samples; (3) heparinized EDC-PEI treated acellular tissue samples. Controlled release of VEGF and its effect on adhesion and proliferation of ECs was evaluated. Results: In the present study, binding and release of VEGF had better performance in heparinized EDC-PEI treated group, compared with heparinized EDC-alone treated group and heparinized PEI-alone group. We could observe enhanced ability to adhesion and proliferation via modest moisture and effective controlled binding and release of VEGF. Conclusion: Binding of VEGF in heparinized EDC treated group was stable, while release of VEGF in heparinized treated group was adjusted freely. Interestingly, controlled binding and release of VEGF could exert beneficial effect on adhesion and proliferation of ECs in heparinized EDC-PEI treated group.

Crosslinking of Bovine Pericardia Using Procyanidins

The aim of this study was to evaluate the crosslinking effect of a naturally crosslinking reagent-procyanidins(PA)-on the materials of bioprosthetic heart valves.After fixing bovine pericardial tissues by procyanidins,crosslikng characteristics,mechanical properties,in vitro enzymatic degradation resistance,the hydrophilicity and hemolysis tests were examined.The results showed that the fixation of biological tissue with glutaraldehyde(GA) or procyanidins increased its denaturation temperature,the surface hydrophilicity and mechanical properties as well as in vitro enzymatic degradation resistance.There were no significant differences in denaturation temperature,mechanical properties,the hydrophilicity and the in vitro enzymatic degradation between the glutaraldehyde and procyanidins fixed tissues.However,the ultimate tensile strength of the procyanidins fixed tissues was significantly superior to the glutaraldehyde fixed tissues.The hemolysis tests showed that hemolysis rate of the procyanidins fixed tissues was lower than that of the glutaraldehyde fixed tissues.This study shows that procyanidins can crosslink which bovine pericardiaa effectively without toxicity.Our results suggest that this method might be a useful approach for the preparation of bioprosthetic heart valve.