Bifunctional polyethersulfone hollow fiber with a porous, single-layer skin for use as a bioartificial liver bioreactor

A bioartificial liver bioreactor requires a bifunctional hollow fiber that is hemocompatible on one side and cytocompatible on the other side. In this study, we developed a single-layer skin polyethersulfone (PES) hollow fiber with smooth inner surface and rough/porous outer surface for an artificial liver bioreactor. The hemocompatibility of the inner surface was evaluated by hemolysis, complement activation and clotting time. The cytocompatibility of the outer surface with HepG2 cells was examined by morphology, proliferation and liver-specific functions. The inner surface of the PES hollow fiber exhibited lower hemolysis and complement activation than cellulose acetate (CA) hollow fiber and a prolonged blood coagulation time. HepG2 cells readily adhered to the outer surfaces of the PES hollow fibers, and proliferated to form multicellular aggregates with time. Furthermore, HepG2 cells cultured on the outer surface of the PES hollow fiber exhibited higher proliferation ability and liver-specific functions than those grown on the CA hollow fiber. These results suggest that the single-layer skin PES hollow fiber is a bifunctional hollow fiber with good hemocompatibility on the inner side and cytocompatibility on the outer side. Thus, porous and single-layer skin PES hollow fibers may have potential as materials for an artificial liver bioreactor.     

Effect of sterilization process on surface characteristics and biocompatibility of pure Mg and MgCa alloys

The aim of this work was to investigate the effect of various sterilization methods on surface characteristics and biocompatibility of MgCa alloy, with pure Mg as a comparison, including steam autoclave sterilization (SA), ethylene oxide steam sterilization (EO), glutaraldehyde sterilization (GD), dry heat sterilization (DH) and Co60 γ ray radiation sterilization (R) technologies. The surface characterizations were performed by environmental scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, water contact angle and surface free energy measurement, whereas the cytotoxicity and hemocompatibility were evaluated by cellular adhesive experiment, platelet adhesion and hemolysis test. The results showed that the five sterilization processes caused more changes on the surface of MgCa alloy than that on the surface of pure Mg. The GD sterilization caused the most obvious changes on the surface of the pure Mg, and the SA sterilization made the largest alteration on the MgCa alloy surface. The GD and DH sterilization processes could cause increases on surface free energy for both pure Mg and MgCa alloys, while the other three sterilization processes reduced the surface free energy. The DH and GD sterilization processes caused the least alteration on the cell adhesion on pure Mg surface, whereas the EO sterilization performed the greatest impact on the cell adhesion on the Mg–Ca alloy surface. The hemolysis percentage of pure Mg and MgCa alloys were reduced by SA sterilization, meanwhile the other four sterilization processes increased their hemolysis percentages significantly, especially for the EO sterilization.     

通用高分子材料的化学和生物改性及其血液相容性研究

功能化与高性能化的通用高分子材料在医用耗材及器械领域有着广泛的应用。作为重要的医用材料之一,血液相容性是首先需要解决的关键科学问题。通用高分子的血液相容性可通过化学和生物修饰来实现。采用的方法大体分为本体改性和表面改性。本体改性主要通过反应接枝和反应共混实现;而表面改性则主要通过在材料表面制备亲水性聚合物刷或亲水层、固定生物活性分子和形成生物仿生膜3种方法来实现。目前,生物材料的血液相容性研究主要集中在血浆蛋白吸附、血小板粘附和红细胞溶血3个方面。结合本课题组近期在生物医用材料领域的研究成果,简要介绍了国内外近年来通用高分子材料的化学和生物改性及其血液相容性研究进展。     

医用高氮无镍奥氏体不锈钢的制备与生物相容性研究

主要探讨不同含氮量的无镍奥氏体不锈钢材料对血管内皮细胞及血小板粘附的影响。通过溶血率和血小板粘附试验考察不同含氮量的无镍奥氏体不锈钢材料的血液相容性;通过MTT试验和细胞粘附试验考察不同含氮量的无镍奥氏体不锈钢材料的细胞相容性。结果表明不同含氮量的无镍奥氏体不锈钢材料的溶血率都低于国家标准的5%,对血小板粘附的影响不显著;粘附在高氮无镍奥氏体不锈钢材料表面的血管内皮细胞数量均多于钛合金材料,且细胞生长状态良好;细胞毒性试验表明,不同含氮量的高氮无镍奥氏体不锈钢材料和对照组钛合金材料对血管内皮细胞没有产生明显的毒副作用。     

Hemocompatibility investigation of the NiTi alloy implanted with tantalum

A composite TiO₂/Ta₂O₅ nano-film has been formed on the NiTi shape memory alloy by Ta implantation. The wettability, protein adsorption, platelets adhesion and hemolysis tests are conducted to evaluate the hemocompatibility. The contact angle measurements showed that the surface of the NiTi alloy kept hydrophilic before and after Ta implantation, although the water contact angle increased with the increasing of implantation current. Both of the surface energy and the interfacial tension decreased after Ta implantation. The protein adsorption behavior was investigated by ¹²⁵I isotope labeling. The fibrinogen adsorption was enhanced by a high surface roughness or a large interfacial tension, while the albumin adsorption was insensitive to the surface modification. Platelet adhesion and activation were weakened and the hemolysis rate was reduced at least 46% after Ta implantation due to the decreased surface energy and improved corrosion resistance ability, respectively.     

Orientation phenomena in chromophore DR1-containing polymer films and their non-linear optical response

The effectiveness of chromophore alignment in polymer films following corona poling can be assessed by the generated second harmonic signal. Optimization of the stability and strength of this nonlinear optical response may improve with a better understanding of the underlying principal order phenomena. Structural analysis by vibrational, optical, and ¹H NMR spectroscopy reveals side chain tacticity, aggregation effects, and changes in orientation as a function of temperature. Co-polymers with the functionalized chromophore Disperse Red 1 methacrylate (MDR1) were prepared for three different methacrylate types. High side chain polarity and short side chain length increase generally chromophore aggregation in films, whereas the very long poly-ether side chains in PMEO based co-polymers are wrapped separately around the DR1 entities. Side chain tacticity depends on space requirements, but also on the capacity of side groups to form OH-bridges. Side chain tacticity might present an additional parameter for the assessment of chromophore aggregation and poling induced alignments. Stepwise heating of co-polymer films causes an increase in the number of random over ordered side chain arrangements. Cross-linking by anhydride formation is observed after heating the methacrylic acid based co-polymer.     

Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

The combination of graphene oxide (GO) with robust mechanical property, silk fibroin (SF) with fascinating biological effects and hydroxyapatite (HA) with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibility tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SF/GO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.     

Hemocompatibility of poly(ether imide) membranes functionalized with carboxylic groups

Materials for blood-contacting applications have to meet high requirements in terms to prevent thrombotic complications after the medical treatment. Surface induced thrombosis, e.g., after application of cardiovascular devices, is linked clearly to the activation of coagulation system and platelet adhesion and activation. The flat sheet poly(ether imide) membrane (PEI) was modified by binding of iminodiacetic acid (IDA) for different periods of time to obtain surfaces with carboxylic (-COOH) groups, namely PEI-1 (modified for 1 min) and PEI-2 (modified for 30 min). The successful binding of the ligands was monitored by thionin acetate assay. The physico-chemical characteristics of the materials were analyzed by SEM, AFM, water contact angle, and Zeta potential measurements. Hemocompatibility of the polymer materials was studied by analyzing the activation of coagulation system (plasma kallikrein-like activity) and platelet adhesion/activation by using immunofluorescence technique. The blood response to PEI membranes was compared to that of a commercial poly(ethylene terephthalate) (PET) membrane. Our results showed that the increase of the negative charges on the modified PEI membrane surfaces (number of -COOH groups) caused a higher contact activation of the coagulation system and a higher rate of platelet adhesion and activation compared to non-modified PEI. However, overall the hemocompatibility of all PEI membranes was higher than that of PET.     

Evaluation on biocompatibility of biomedical polyurethanes with different hard segment contents

In this paper, polyurethane (PU) materials with different contents of hard segment (20%, 25%, 30%) were prepared based on hexamethylene diisocyanate and polycarbonate diols by solution polymerization. The obtained polycarbonate-urethane (PCU) elastomers were characterized by very good hydrophobic property and excellent resistance to hydrolysis. Hemolysis, recalification time and platelet-rich plasma adhesion were used to evaluate the blood compatibility of the materials. L929 cells cultured with leach?liquor of these PU membranes were selected to perform the cytotoxicity experiments. The results indicate that the hemolysis rates of PU membranes are all less than 5%, which can meet the requirement of the national standards for biomaterials. However, compared with 20% and 30% groups, the recalification time of the sample containing 25% hard segment is longer, while the number of platelet adhesion is less. Additionally, cells cultured in the leach liquor of PU membranes with 25% hard segment proliferated relatively more thriving, meaning that this proportion of the material has the lowest cytotoxicity.     

钽离子注入对镍钛合金表面生物学性能的影响

镍钛合金血管支架植入后可引发血栓和支架再狭窄,且对损伤的血管内壁无修复作用,需进行表面改性赋予其抗凝血和促内皮化生物学功能。本研究采用等离子体浸没离子注入与沉积(PIII&D)技术将钽(Ta)注入至镍钛合金,研究Ta离子注入对镍钛表面理化特性及生物学性能的影响规律。结果表明,调控Ta离子注入时间,可在镍钛表面分别构建含Ta、Ta/Ta₂O₅、Ta/Ta₂O_5–x/Ta₂O₅三种不同组分的改性层。各种改性样品中,含Ta/Ta₂O_5–x/Ta₂O₅的改性镍钛表面亲水性均更好,可提供更多细胞附着位点,促进人脐静脉内皮细胞早期粘附和铺展,并提高其增殖能力。相比仅含单质Ta的改性镍钛表面,含Ta/Ta₂O_5–x/Ta₂O₅改性镍钛表面的血液相容性更高,血小板粘附数量显著减少,且基本保持...     

聚乙二醇化环维黄杨星D的合成及结构表征

将亲水性的聚乙二醇接枝到环维黄杨星D的氨基侧链上,得到一系列未见报道的聚乙二醇化环维黄杨星D,用IR,1H-NM R对产物进行了表征分析,同时进行了水溶性、水接触角及溶血性实验。结果表明,活化的聚乙二醇被成功地接枝到环维黄杨星D上,使其后者亲水性得到了很大的提高,且对红细胞无破坏作用,有优良的血液相容性,为开发环维黄杨星D新型静脉注射剂提供了实验依据。     

Standardization of incubation conditions for hemolysis testing of biomaterials

Hemolysis testing is the most common method to determine the hemocompatibility properties of biomaterials. There is however no consensus on the procedures of hemolysis testing due to insufficient comparative studies on the quality of the red blood cells used and the experimental conditions of testing. In this study we determined the effects of a number of incubation variables on the sensitivity and reproducibility of the hemolysis test using positively as well as negatively responding biomaterials and compared these results to those obtained according to the American Society for Testing and Materials (ASTM) standard. The ASTM standard method recommends hemolysis testing with highly diluted rabbit blood that is static incubated for 3 h. In this study we found that 24 h incubation of a biomaterial sample at 37 °C in slightly diluted human blood or with washed red blood cells was the most sensitive hemolysis test. Moreover usage of cryopreserved human RBC in the hemolysis test seemed to be a good alternative for fresh RBC since cryopreserved and fresh human RBC gave similar results in the hemolysis test. Hemolysis testing by exposing diluted rabbit erythrocytes to biomaterials as according to the ASTM method or by exposing biomaterials extract in saline to washed human red blood cells gave a different outcome and appeared not to be representative for clinical applications.     

Polypropylene non-woven fabric membrane via surface modification with biomimetic phosphorylcholine in Ce(IV)/HNO3 redox system

Surface modification of polypropylene non-woven fabric membrane (NWF) for improving its hemocompatibility was developed by grafting a biomimic monomer, 2-methacryloyloxyethyl phosphorycholine (MPC). The NWF membrane surface was first activated by potassium peroxydisulfate to form hydroxyl groups, and then grafted with MPC using ceric (IV) ammonium nitrate as the redox initiator. The surface chemical changes before and after modification were confirmed by Fourier transform infrared spectroscopy with an ATR unit (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS); the water contact angle results showed the gradual changes in wettability from hydrophobic to hydrophilic surface. Meanwhile, the hemocompatibility of these samples was also evaluated by protein adsorption and platelet adhesion. These experimental results exhibited that the introduction of poly(MPC) onto the NWF membrane surfaces substantially improved their hemocompatibility. The feasibility and simplicity of this procedure may lead to potential applications of NWF membranes in biomedical separation and blood purification.     

Hemocompatibility and macrophage response of pristine and functionalized graphene

Graphene and its derivatives are being proposed for several important biomedical applications including drug delivery, gene delivery, contrast imaging, and anticancer therapy. Most of these applications demand intravenous injection of graphene and hence evaluation of its hemocompatibility is an essential prerequisite. Herein, both pristine and functionalized graphene are extensively characterized for their interactions with murine macrophage RAW 264.7 cells and human primary blood components. Detailed analyses of the potential uptake by macrophages, effects on its metabolic activity, membrane integrity, induction of reactive oxygen stress, hemolysis, platelet activation, platelet aggregation, coagulation cascade, cytokine induction, immune cell activation, and immune cell suppression are performed using optimized protocols for nanotoxicity evaluation. Electron microscopy, confocal Raman spectral mapping, and confocal fluorescence imaging studies show active interaction of both the graphene systems with macrophage cells, and the reactive oxygen species mediated toxicity effects of hydrophobic pristine samples are significantly reduced by surface functionalization. In the case of hemocompatibility, both types of graphene show excellent compatibility with red blood cells, platelets, and plasma coagulation pathways, and minimal alteration in the cytokine expression by human peripheral blood mononuclear cells. Further, both samples do not cause any premature immune cell activation or suppression up to a relatively high concentration of 75 μg mL(-1) after 72 h of incubation under in vitro conditions. This study clearly suggests that the observed toxicity effects of pristine graphene towards macrophage cells can be easily averted by surface functionalization and both the systems show excellent hemocompatibility.     

Hydrothermal synthesis of fluorescent silicon nanoparticles using maleic acid as surface-stabilizing ligands

Water-soluble silicon nanoparticles (SiNPs) have been synthesized with photoluminescence quantum yield more than 32% via a hydrothermal treatment of 3-aminopropyltriethoxysilane as silicon sources and maleic acid (MA) as surface-stabilizing ligands. Prepared SiNPs showed the presence of carboxylic acid groups through the incorporation of MA. The presence of 48.8 and 51.2% of Si–Si and Si–O binding was observed in the resulting carboxylic acid-functionalized SiNPs (COOH-SiNPs). As revealed by the fluorescence lifetime images, COOH-SiNPs possesses several fluorophores mainly composed of above Si–Si binding inside of single particle, which explains the excitation-dependent fluorescence emission behavior of COOH-SiNPs. Also, the presence of oxides mainly composed of Si–O binding and MA on the surface of COOH-SiNPs provides long-term stability for both fluorescence and dispersion. The potential use of COOH-SiNPs as fluorescence bioimaging agents for cellular media has been demonstrated. COOH-SiNPs showed excellent cell viability more than 91% for both MDAMB and MDCK cells even in 1,000 ppm concentration, and multicolor fluorescence imaging (blue, green, and red) of MDAMB cells was successfully accomplished with different excitation wavelengths.     

Development of polymer concrete with polybutadiene matrix

Composite materials based on polymer binders and mineral fillers are widely used as structural chemically resistant, vibration and impact proof materials for industrial construction and chemical machinery. Up to the present hetero-chain polymers, unsaturated polyesters, polyepoxy and polyuretanes are applied as binders of such concrete-polymer composites. A new type of conglomerate composites-polymer concrete based on polybutadiene belonging to the liquid rubbers (RubCon—Rubber Concrete) has been enveloped and investigated. Such a rubber is used as a binder hardened by sulphur in the presence of special admixtures. Quartz sand and fly ash may be used as fillers and fine grained granites and basalt chipping as coarse aggregate. The resulting material has high acid and alkali resistance, toughness and adhesion to metal reinforcements, low water absorption and remarkable compression strength (80–90 MPa). A series of RubCon compositions are presented and industrial production technology for chemically resistant items and structures is worked out. The experimental samples of the material were successfully applied in real plant conditions at constant action of concentrated solutions of sulphuric acid and caustic potash.     

紫外光照法制备有机表面单分子羧基层

研究了通过紫外光辐照,在双向拉伸聚丙烯和低密度聚乙烯膜表面制备单分子层羧基的方法。激发态的丙酮分子先从有机聚合物的表面夺取C-H键的氢,生成大分子链自由基;然后过氧化丁二酸(BOS)裂解产生的带羧基的自由基与大分子链自由基偶合形成羧基。通过水接触角(CA)、紫外吸收光谱(UV)、X射线光电子能谱(XPS)和酸碱滴定等试验,证明在聚合物基材表面有羧基。对反应的工艺参数,如光照强度,光照时间、反应液的配方及BOS浓度等进行了考察。最佳的条件为:光强为8500μW/cm2,丙酮/水=3/7,BOS溶液为1%(质量/体积),光照15min。     

TiN／Ag多层膜的生物相容性研究

使用离子束辅助沉积（IBAD）的方法，在医用不锈钢317L的基底上制备TiN／Ag多层膜．在TiN／Ag多层膜具有良好的抗茵性和抗腐蚀性的研究基础上，通过细胞毒性试验和溶血试验评价了TiN／Ag多层膜的生物相容性．试验结果表明：TiN／Ag多层膜样品的细胞毒性等级在0～1之间；溶血率〈5％，符合生物医学材料的标准．这些说明TIN／Ag多层膜不仅具有抗菌性和抗腐蚀性，而且具有良好的生物相容性．     

Si-N-O薄膜结构对薄膜血液相容性的影响

采用非平衡磁控溅射(UBMS450)法在(100)单晶硅表面制备Si-N-O薄膜.利用X射线光电子能谱(XPS)表征薄膜的成分结构;用血小板粘附试验表征薄膜结构对薄膜血液相容性的影响.研究结果表明,以无机Si为主的Si-N-O薄膜,其血液相容性较差;键合少量O的Si3N4薄膜,其血液相容性较佳.Si-N-O薄膜中N含量和O含量的变化,是导致薄膜结构变化的重要因素.     

PDMS content affects in vitro hemocompatibility of synthetic vascular grafts

An unsolved problem when employing small-diameter vascular grafts for aorto-coronary by-pass and peripheral reconstruction is the early thrombotic occlusion. The PEtU-PDMS is a new elastomeric material, composed of poly(ether)urethane and polydimethylsiloxane, synthesized to realize grafts with improved hemocompatibility characteristics. In order to investigate the effect of PDMS content on hemocompatibility, three different percentages of PDMS containing grafts (10, 25 and 40) were evaluated. Grafts realized with Estane 5714-F1 and silicone medical grade tubes were used as references. The hemocompatibility was investigated by an in vitro circuit in which human anticoagulated blood was circulated into grafts by a peristaltic pump modified to obtain a passive flow. For each experiment, 40 cm length graft was closed into a circular loop and put in rotation for 2 h at 37 degrees C. At the end of the experiments different parameters regarding platelet adhesion and activation were evaluated: circulating platelets count, beta-thromboglobulin release, platelet CD62P expression and amount of monocyte-platelet conjugates. PEtU-PDMS grafts with 25 and 40% of PDMS induced the lowest platelet adhesion, plasma level of beta-TG and amount of monocyte-platelet conjugates. No significative variations were observed in CD62P expression. In conclusion, PDMS content significatively affects blood-graft surface interaction, in fact higher PDMS percentage containing grafts showed the best in vitro hemocompatibility.