p(HEMA-MMA)表面固定I-型胶原和碱性成纤维生长因子(bFGF)改善细胞相容性的研究

材料表面固定生物分子一直都被认为是其提高其细胞相容性有效的途径。本文采用羧基二咪唑(CDI)作为缩合剂,使p(HEMA-MMA)表面羟基与胶原中氨基发生缩合反应,从而将I-型胶原接枝在材料表面。然后利用"接枝-吸附"的方法,将I-型胶原和bFGF混合层吸附固定于材料表面,形成稳定的胶原与bFGF涂层。红外光谱(FTIR)和原子力显微镜(AFM)证实了该种固定方法的成功。静态接触角显示材料表面亲水性较改性前略微降低。涂层稳定性实验结果表明在类似人体环境(pH=7.4)下涂层具有良好的稳定性。细胞粘附性实验以及MTT实验一致显示改性后材料的细胞相容性得到明显提高。因此,Col/bFGF-p(HEMA-MMA)有望成为能够被宿主机体所接受的生物材料。     

羟基磷灰石/聚乳酸微粒复合生物支架的体外细胞相容性评价

利用溶液共混法以及溶剂挥发法制备了羟基磷灰石(Nano-HA)/聚乳酸(PLA)微粒,再粘结微粒加工成三维多孔Nano-HA/PLA微粒复合生物支架。借助相差显微镜、扫描电子显微镜和MTT法检测了鼠骨髓基质细胞(BMSCs)在该支架材料上的生长情况,通过细胞形态学观察和细胞增殖情况评价了该复合生物支架材料的生物相容性。结果表明,SEM观察到支架材料上培养细胞4d后,细胞主要附着、铺展在支架的低洼处或孔洞处表面,并向孔洞深部沿壁生长;在支架材料上培养细胞8d后,细胞多为梭形形态,并有许多生长角,直接贴附于支架的微粒表面,开始连片生长,有明显的增值,各组没有变形、坏死现象。支架材料上培养细胞2,3,4,5,6和8d的MTT检测表明,各实验组RGR均达到100%以上,细胞毒性为0级;细胞在支架材料上的生长曲线显示,实验组细胞活力比对照组高26%。因此,该Nano-HA/PLA微粒复合生物支架没有细胞毒性,并对细胞有良好的粘附和增殖能力,为较具潜力的骨修复材料。     

纤维素/海藻酸钠复合气凝胶的表面功能化与仿生矿化

通过高碘酸钠和亚氯酸钠的2次氧化法,对纤维素/海藻酸钠复合气凝胶进行表面氧化改性,将纤维素和海藻酸钠表面C2和C3位置的羟基氧化为羧基,有效地提高了复合气凝胶的矿化能力。通过傅里叶红外光谱仪(FT-IR)、扫描电镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、体外细胞毒性测试等对羧基化改性前后在复合气凝胶支架上的沉积物进行表征。结果表明,改性后复合气凝胶表面的磷灰石形成速率更快,晶粒更小,沉积层更均匀;改性复合气凝胶表面的羧基具有更强的Ca2+结合能力,可以诱导Ca2+吸附在气凝胶表面,使矿化能力提高。同时,小鼠成纤维细胞实验表明,矿化后的复合气凝胶无毒性,可以促进细胞生长和分化,是性能良好的骨组织工程材料。     

三维多孔碳纤维/聚乳酸/壳聚糖复合支架材料的体外细胞相容性评价

利用溶液共混法以及冷冻干燥法制备了三维多孔碳纤维/聚乳酸/壳聚糖(CF/PLA/CS)复合生物支架材料,通过相差显微镜和扫描电子显微镜检测了鼠骨髓基质细胞（BMSCs）与该材料的生物相容性,得到了MTT生长曲线,评价了材料的毒性。 结果表明,以实验组材料的浸提液培养细胞,8 d后细胞开始连片生长,没有观察到细胞变形、坏死现象;在实验组材料上培养4 d后细胞的SEM图像显示,细胞形貌正常,并已开始向孔隙深部生长;MTT法绘制的增值曲线表明,培养4 d后实验组的细胞增殖速度高出空白对照组30%。 以上细胞形态学观察法和细胞增殖法评价结果表明,三维多孔 CF/PLA/CS复合材料没有细胞毒性,并对细胞有良好的粘附、增殖能力,有望成为骨修复材料。     

明胶在聚氨酯表面的固定化及其对内皮细胞生长的促进作用

理想的组织工程支架材料应具备有效促进细胞生长的能力和良好的组织相容性 .然而现有的聚合物生物材料大多呈现疏水性 ,不能有效支持细胞的生长 [1,2 ] .细胞外基质和血清中含有对细胞粘附、生长和繁殖有显著促进作用的多种活性因子 ,如纤维粘连蛋白 ( Fn)、层粘连蛋白 ( L aminin)、胶原( Collagen)、多聚赖氨酸和冷析蛋白 ( CIG)等 [3～ 5] ,把这些因子固定到材料表面 ,可为细胞的粘附生长提供理想的条件 .本文通过碳二酰亚胺脱水缩合技术 ,将明胶 ( Gelatin)共价键合到聚甲基丙烯酸接枝改性的聚氨酯 ( PU- g- PMAA)薄膜表面 ,并初…     

生物医用高分子纤维材料

综述了医用的高分子纤维材料及其改性的方法。医用高分子纤维材料包括天然高分子及合成高分子两大类。其中包括不可降解的及可降解的高分子纤维材料。利用聚合物共混、交联、纤维表面改性,如等离子体处理、纤维表面化学反应及聚合物的表面接枝等物理化学方法可对医用纤维进行改性,改善纤维的力学性能、生物相容性,并使之具有细胞粘附性,利于组织的生长。     

聚合物材料表面纳米条纹对生物细胞生长的影响

20世纪 80年代后期 ,工程学科与生命学科的交叉融合产生了组织工程学 [1,2 ] ,细胞与生物材料之间的相互作用是组织工程学的一个主要领域 .细胞必须与材料发生适当的粘附 ,才能进行迁移、分化和增殖 ,细胞与材料粘附及随后的扩散能力的大小主要由材料表面的物理和化学性质所决定 [3,4 ] .目前 ,材料表面改性以提高细胞粘附力是组织工程学的一大难题 .聚苯乙烯 (PS)以其无毒、高透明度、低成本以及易加工等性能 ,被广泛应用于基础医学研究及临床医学实验 [5,6 ] .未改性 PS的生物相容性较差 ,只有表面改性后才能用于细胞培养 .目前文献报道…     

聚己内酯/卵磷脂的纺丝支架构建组织工程血管

合成的聚己内酯(PCL)经天然的卵磷脂(Phosphatidylcholine,PC)填充改性后,通过电纺丝技术加工得到三维多孔的纤维支架。卵磷脂含有的两性离子基团,可以显著改善PCL支架材料的亲水性,进而提高支架材料的细胞相容性。体外细胞增殖实验表明,骨髓间充质干细胞(MSCs)在含有5wt%卵磷脂的改性支架表面生长得最好。作为种子细胞的MSCs在流动培养下,通过力学刺激在管状支架内壁形成了多层细胞。通过对样品染色切片和荧光照片的观察,种子细胞MSCs与对照组的血管平滑肌细胞(SMCs)一样,有向改性支架内部生长的趋势。本文以这种PC填充改性PCL材料的纤维支架作为组织工程血管,对其进行了初步的探索。     

聚羟基脂肪酸酯的亲水性改性及其与人脐静脉内皮细胞相容性的研究

用丝素蛋白(SF)对微生物合成的高分子聚合物聚(3-羟基丁酸酯-co-3-羟基己酸酯)(PHBHHx)进行亲水改性,以提高材料的生物相容性.水接触角测定和表面自由能分析表明,丝素蛋白在支架表面吸附,使PHBHHx材料表面的水接触角从90°降至51°,表面自由能从37.9 mJ/m2增至57.4 mJ/m2,因而增加了材料的亲水性.进一步对亲水性改性前后PHBHHx多孔支架与人脐静脉内皮细胞(HUVECs)的相容性进行了比较.MTT法细胞活力分析表明,细胞在支架上培养3,5,7天后,其在SF改性PHBHHx多孔支架上的活力显著高于在未改性的PHBHHx支架上的活力;扫描电镜观察细胞生长形貌表明,细胞在改性后多孔支架上黏附及生长5天后,形成了连续细胞单层,其生长状态优于在未改性的PHBHHx支架上的生长状态;胶原含量测定表明细胞在改性后支架上比在未改性支架上有更好的胶原分泌能力,即改性后支架更利于诱导HUVECs分泌细胞外基质(ECM)从而构建类似体内的生长环境.     

新型改性聚己内酯型聚氨酯弹性体的合成及性能

用不同种类异氰酸酯[脂肪族六亚甲基二异氰酸酯(HDI)和脂环族异佛尔酮二异氰酸酯(IPDI)]对聚己内酯(PCL)进行改性,得到两端为羟基的异氰酸酯改性的PCL预聚体.将未改性和改性的PCL端羟基进行磷酸化后[磷酸化组分PCL210磷酸酯(A)、PCL205/HDI磷酸酯(B)和PCL205/IPDI磷酸酯(C)]与双官能度的环氧(1,4-丁二醇二缩水甘油醚,E)进行开环交联反应,得到生物相容且可降解的聚己内酯型聚氨酯弹性体材料(AE,BE和CE).聚己内酯型聚氨酶弹性体的力学性能、静态水接触角、体外降解/溶胀和细胞毒性测试结果表明,PCL异氰酸酯的改性有助于提高材料的强度、弹性、耐疲劳性和降解速率,同时未明显提高材料的细胞毒性.     

Preparation of chitosan–silica/PCL composite membrane as wound dressing with enhanced cell attachment

In the present study, the asymmetrical polycaprolactone membranes were synthesized using phase inversion method and modified by addition of Pluronic (F‐127) and sodium hydroxide treatment to improve the cell attachment. The chemical structure, physical properties and mechanical behavior of the membranes as well as cell attachment and proliferation on them were characterized and compared to determine the appropriate membrane used in wound dressing fabrication. Then, a composite membrane as wound dressing capable of drug controlled‐release was prepared composed of two merged layers: an asymmetrical poly(ε‐caprolactone) layer coated with a drug‐loaded chitosan – silica matrix. Drug release behavior and biocompatibility of the final system were evaluated. The results showed that the polycaprolactone modified membrane provides appropriate properties to expand fibroblast cell adhesion and proliferation. This in‐vitro study also showed that the controlled‐release composite wound dressing was developed with approximately 70% cumulative release rate, which provided a porous substrate to support skin cells. Copyright © 2017 John Wiley & Sons, Ltd.     

Physico-chemical and thermodynamic aspects of fibroblastic attachment on RGDS-modified chitosan membranes

In the present study, the cell attachment/spreading behaviour of L929 mouse fibroblasts on chitosan membranes was evaluated by using physico-chemical properties. For this purpose chitosan membranes were prepared and then photochemically modified with the cell adhesive peptide RGDS (Arg-Gly-Asp-Ser). The physico-chemical properties of unmodified (CHI) and RGDS-modified chitosan (CHI-RGDS) membranes were evaluated by calculating surface free energy (γ_sv) and interfacial free energy (γ_sw) values using captive bubble contact angle measurements and harmonic mean equation. The cell attachment experiments were performed both in 10% FBS containing and serum-free media with CHI and CHI-RGDS membranes. Eventually, it was not possible to predict a direct relationship between the change in physico-chemical properties and L929 cell attachment behaviour. The experimental results obtained from cell attachment agree with the theoretical prediction for the free energy of adhesion except for the cell attachment on CHI membrane in serum-free medium. Although a negative interfacial free energy of adhesion was calculated for CHI membrane in serum-free medium (ΔF_adh = −2.19 ergs/cm²), the cell attachment was poor (70%) compared to CHI-RGDS (90%) and none of the cells were spread on CHI surface to gain a fibroblastic morphology. Negative energy of adhesion was calculated for CHI and CHI-RGDS in 10% FBS medium, in which 100% of cells were attached on the membranes correlating with the thermodynamic approach. It can be suggested that, adsorption of serum proteins strongly affected the cell attachment meanwhile the presence of biosignal RGDS molecules triggered the cell spreading in serum medium.     

Microscale control over collagen gradient on poly(L-lactide) membrane surface for manipulating chondrocyte distribution

A collagen gradient was constructed to interrogate cell adhesion on a poly(L-lactide) (PLLA) membrane surface. Utilizing a microinfusion pump, gradients of amino groups were generated on the PLLA surface by an aminolysis method. Immobilization of collagen onto the gradient surfaces was performed by glutaraldehyde (GA) coupling to form the collagen gradients. The -NH(2) and immobilized collagen density profiles on the PLLA membranes were quantitatively determined by ninhydrin and hydroproline (Hyp) analysis, respectively. By using fluorescein isothiocyanate (FITC) labeled collagen (FITC-Col), the profile of the as-prepared collagen gradient was directly monitored by a fluorescence microscope. The scanning force microscopy and water contact angle studies revealed that the morphology and wettability of the modified membranes changed progressively as a function of position along the gradient surface. Rabbit auricular chondrocytes were cultured on the collagen gradient membranes to test their cellular response. The attachment and spreading behaviors of the chondrocytes were dependent on the surface collagen density. These results indicate a surface on which the variation of collagen gradient strongly modifies the biological response of chondrocytes.     

A nanofibrous composite membrane of PLGA-chitosan/PVA prepared by electrospinning

Tissue engineering scaffolds produced by electrospinning feature a structural similarity to the natural extracellular matrix. In this study, poly(lactide-co-glycolide) (PLGA) and chitosan/poly(vinyl alcohol) (PVA) were simultaneously electrospun from two different syringes and mixed on the rotating drum to prepare the nanofibrous composite membrane. The composite membrane was crosslinked by glutaraldehyde vapor to maintain its mechanical properties and fiber morphology in wet stage. Morphology, shrinkage, absorption in phosphate buffered solution (PBS) and mechanical properties of the electrospun membranes were characterized. Fibroblast viability on electrospun membranes was discussed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and cell morphology after 7 days of culture. Results indicated that the PBS absorption of the composite membranes, no matter crosslinked or not, was higher than the electrospun PLGA membrane due to the introduction of hydrophilic components, chitosan and PVA. After crosslinking, the composite membrane had a little shrinkage after incubating in PBS. The crosslinked composite membrane also showed moderate tensile properties. Cell culture suggested that electrospun PLGA-chitosan/PVA membrane tended to promote fibroblast attachment and proliferation. It was assumed that the nanofibrous composite membrane of electrospun PLGA-chitosan/PVA could be potentially used for skin reconstruction.     

Polyelectrolyte complex membranes for specific cell adhesion

The presentation of bioactive ligands on biomaterial surfaces is often confounded by the adsorption of proteins present in the biological milieu, rendering any type of cellular response nonspecific. We have engineered a polyelectrolyte complex membrane that demonstrates specific adhesion of various cell types for both two-dimensional (2D) and three-dimensional (3D) cell culture systems. Specific cell adhesion is achieved by a three-tiered structure: a silica cross-linked polycation as the bottom (first) tier, a nonfouling polyanion-poly(ethylene glycol) (PEG) conjugate as the intermediate (second) tier, and the cell-adhesion ligand as the top (third) tier. Each tier of the membrane was characterized in terms of chemical composition and dimensions. Epithelial cells (primary human cortical renal cells and a hepatocellular carcinoma cell line) cultured on the membranes exhibited little cell attachment on the polyanion-PEG second tier and good cell adhesion on the RGD-modified third tier. Thus, the second tier allowed the effect of cell adhesion due to the ligand (third tier) to be isolated and distinguished from nonspecific cell attachment to the first tier. For the culturing of cells in three dimensions, the three-tiered membrane system was applied using a highly swellable chitosan membrane as the first tier. The resulting cell-membrane construct was uniformly dispersed and centrifuged to form a matrix that interacted intimately with cells in the form of a pellet. Presentation of RGD in the latter format enhanced the viability of human mesenchymal stem cells (hMSCs) over controls without RGD.     

Impedance Analysis of Single Melanoma Cells in Microfluidic Devices

The electrical impedance analysis of single cells can provide information on cells’ pathological condition in various environments. Cell electrical properties are affected by factors such as the location, adhesion, and size of the cell. The proposed microfluidic device captures a single cell, maintains growth conditions, and allows single‐melanoma‐cell impedance to be measured using an impedance analyzer and a function generator. The rate of impedance variation (ROIV) can be used to determine cell growth conditions. Cellular apoptosis affects cell size and membrane surface area, and thus the electrical properties of cells. At 24 h without Antrodia cinnamomea (AC) addition, ROIV was 15.23 %, 17.04 %, and 12.60 % at temperatures of 34 °C, 37 °C, and 40 °C, respectively. At 24 h and 37 °C, ROIV was 17.04 %, 40.37 %, and 45.02 % for AC concentrations of 0, 20, and 40 µL/mL, respectively. The results show that the cell impedance variation of cells cultured without AC is much lower than that of cells cultured with AC. Regarding cellular morphology, with AC addition, the cells shrank obviously after 24 h, whereas they barely shrank without AC addition.     

Surface modification of polycarbonate urethane by grafting polyethylene glycol and bivalirudin drug for improving hemocompatibility

As the clinical demand for blood-contacting materials increases, higher requirements are placed on their physicochemical properties, durability and hemocompatibility in vivo. In this work, a multiple functionalized material was developed through a facile modification process. Herein, polycarbonate urethane (PCU) surface was co-modified with polyethylene glycol (PEG) and bivalirudin (BVLD). PCU provides excellent physical and mechanical properties, PEG and BVLD, especially BVLD, enable the surface with outstanding anticoagulant capacity. Specifically, PCU surface was first treated with hexamethylene diisocyanate to introduce active isocyanate groups onto the surface, followed by hydroxy-PEG grafting to improve the hydrophilicity. Finally, BVLD was immobilized on the surface via Michael addition reaction to improve antithrombotic properties. Attenuated total reflection Fourier transforms infrared spectroscopy and UV spectrophotometers were used to confirm the modified surfaces. The hydrophilicity was characterized by static water contact angle measurement, the morphology of the modified surfaces was observed by scanning electron microscopy. Blood compatibility of the modified surfaces was characterized by the hemolysis rate, platelet adhesion assay and cell culture test. The results showed that the BVLD immobilized surface has excellent anticoagulant properties, good fibrin-bound thrombin inhibition, and good resistance against non-specific adhesion of proteins. Hence, the co-modification with PEG and BVLD was proved an encouraging strategy for improving hemocompatibility.     

Photoinduced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on polyethylene membrane surface for obtaining blood cell adhesion resistance

Phospholipid polymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)], was grafted with polyethylene (PE) membrane using photoinduced polymerization technique to make the membrane resistant to cell adhesion. The water contact angle on the PE membrane grafted with poly(MPC) decreased with an increase in the photopolymerization time. This decrease corresponded to the increase in the amount of poly(MPC) grafted on the PE surface. The same graft polymerization procedure was applied using other hydrophilic monomers, such as acrylamide (AAm), N-vinylpyrrolidone (VPy) and methacryloyl poly(ethylene glycol) (MPEG). These monomers were also polymerized to form grafted chains on the PE membrane, and the grafting was confirmed with X-ray photoelectron spectroscopy. Analysis of amount and distribution of plasma proteins at the plasma-contacting surface of the original and the modified PE membranes were analyzed using immunogold assay. The grafting of poly(MPC) and poly(VPy) on PE membrane reduced the plasma protein adsorption significantly compared with that on the original PE membrane. However, the PE membranes grafted with poly(AAm) or poly(MPEG) did not show any effects on protein adsorption. Platelet adhesion on the original and modified PE membranes from platelet-rich plasma was also examined. A large number of platelets adhered and activated on the original PE membrane. Grafting with poly(AAm) did not suppress platelet adhesion, but grafting with poly(MPC) or poly(VPy) on the PE membrane was effective in preventing platelet adhesion. It is concluded that the introduction of the phosphorylcholine group on the surface could decrease the cell adhesion to substrate polymer.     

Poly(ether imide) membranes modified with poly(ethylene imine) as potential carriers for epidermal substitutes

Poly(ether imide) (PEI) membranes were modified with a linear low-molecular weight (PETIM_0.6) and a branched high-molecular weight poly(ethylene imine) (PETIM_60). The membrane surfaces became more hydrophilic and the zeta potentials were shifted from negative to positive zeta values after immobilisation of both PETIM. These measurements also indicated the presence of a swollen surface layer in the case of PETIM_60, while a regular structuring of the surface was observed with scanning force microscopy for PETIM_0.6. A human keratinocyte cell line HaCaT was cultured on the different membranes. It was found that HaCaT cell growth was stimulated by PETIM_0.6. Cells reached earlier confluence on this substratum, while their growth was inhibited on a PEI membrane modified with PETIM_60, which makes PEI membranes modified with PETIM_0.6 a promising material for in vitro culture of epidermal transplants.     

Heparin-like surface modification of polyethersulfone membrane and its biocompatibility

Sulfonated polyethersulfone (SPES) and poly (acrylonitrile-co-acrylic acid-co-vinyl pyrrolidone) (P(AN-AA-VP)), which provided sulfonic acid (SO(3)H) and carboxylic acid groups (COOH), respectively, were used to modify polyethersulfone (PES) membrane with a heparin-like surface by blending method. The SPES was prepared by sulfonation of PES using chlorosulfonic acid as the sulfonating agent, while the P(AA-AN-VP) was prepared through a free radical polymerization. The PES and modified PES membranes were prepared by a phase-inversion technique; the modified membranes showed lowered protein (bovine serum albumin, BSA; bovine serum fibrinogen, FBG) adsorption and suppressed platelet adhesion. For the modified membranes, significant decreases in thrombin-antithrombin (TAT) generation, percentage platelets positive for CD62p expression, and the complement activation on C3a and C5a levels were observed compared with those for the pure PES membrane. Due to the similar negatively charged groups as heparin, the modified membranes effectively prolonged the activated partial thromboplastin time (APTT). Furthermore, the modified membranes showed good cytocompatibility. Hepatocytes cultured on the modified materials exhibited improved functional profiles in terms of scanning electron microscope (SEM) observation and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay compared with those on the pure PES membrane. It could be concluded that the modified membranes with sulfonic acid and carboxylic acid groups were endowed with excellent biocompatibility, and the heparin-like surface modification seemed to be a promising approach to improve the biocompatibility of materials.