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…     

角膜基质细胞在p(HEMA-MMA)改性前后的粘附率、形貌与力学性能变化

采用原子力显微镜(AFM)对改性前后材料表面粘附生长的角膜基质细胞的亲和力、三维形貌和力学性能进行了分析。结果显示,改性后材料的细胞亲和力有较大改善,且材料表面细胞三维形态更加正常,铺展更为舒展,与材料的接触面积较大。细胞力学性能分析也发现改性后材料表面细胞具有更高的粘附力和杨氏模量,以及更低的硬度,说明未改性p(HEMA-MMA)材料具有明显的细胞毒性,这种毒性作用导致在其表面生长的细胞的细胞骨架遭到破坏,细胞健康状态明显不如改性后材料表面细胞。因此,改性后的Col/bFGF-p(HEMA-MMA)更适合作为人工角膜材料使用。     

血液相溶材料的合成研究(Ⅶ)──一类新的抗血小板粘附高分子材料

不凝血性 (Nonthrombogenicity)又称抗凝血性 (Antithrombogenicity) ,是指材料不会触发血液凝固的能力 .如何提高不凝血性一直是高分子生物材料研究的主要任务和中心内容 [1～ 3 ] .但目前抗凝血性最好的三类抗凝血材料 ,即聚乙二醇衍生物 (PEO)、聚磷酰胆碱及肝素化材料等 [4～ 10 ] 仍不能满足心血管医用装置的需要 .材料界面血小板的粘附和活化是导致凝血的重要因素 .活化的血小板不仅可激活多种凝血因子 ,也是材料表面血栓的重要组成部分 .因此 ,对材料界面血小板粘附行为的研究可初步评价材料的血液相容性 [11,12 ] .根据“维持正常…     

组织工程细胞支架及其细胞亲和性改进研究进展

综述近年来组织工程中有关细胞在材料上粘附的机理研究并从生物学观点和材料观点来分析影响细胞亲和性的因素,介绍了目前研究中的改性生物医学材料细胞亲和性的研究方法,并对今后的研究提出了建议。     

表面微图案化聚乳酸膜的制备及其细胞亲和性评价

利用溶剂-非溶剂法(SNS)制备表面具有微孔图案的聚乳酸(PLA)膜和聚苯乙烯(PS)膜,并以微孔PS膜为模板,构建表面具有微岛图案的PLA膜.以此为基础,对所制备的微图案表面对PLA膜亲/疏水性及成骨细胞粘附与增殖性能的影响进行研究.结果显示微图案的存在显著增强了PLA膜的表面疏水性(水接触角90°);成骨细胞在微图案表面具有良好的铺展性,其黏附数量明显高于光滑PLA膜,但细胞的生长曲线相对较平缓,显示微图案表面虽有利于细胞在PLA膜表面的粘附与铺展,但对促进细胞的增殖无贡献.     

重氮树脂与牛血清白蛋白共价结合自组装膜及其表面细胞培养

细胞支架作为组织工程的组成部分为细胞生长提供了最佳微环境 ,并对细胞生长与功能进行控制 .由于细胞对支架表面的生物识别是细胞附着、生长和增殖的基本前提 ,所以对材料表面的功能化是一个重要的课题 [1,2 ] . Shoichet等 [3 ] 通过化学反应或等离子体处理的方法 ,将蛋白质引入到材料表面而使其功能化 .基片在两种带有相反电荷的聚电解质溶液中交替吸附 ,其表面形成致密有序的超薄自组装膜 ,这种层 -层自组装技术不仅制备方法简单 ,无需特殊的设备 ,而且对膜组成和厚度能随意调控 ,以水为介质 ,对环境友好 [4～ 6] ,无疑是一项重要的表…     

含有邻苯二酚基团的材料在抗菌防污领域的研究进展

贻贝是海洋污损生物中最为常见的一类生物,它可以粘附在几乎所有材料的表面,这是由于贻贝能够分泌具有优异粘附性能的贻贝粘附蛋白.贻贝粘附蛋白结构中具有邻苯二酚基团,并已被证明是一种有效的表面改性锚定剂,几乎可以粘附在任何材料表面.本文针对含有邻苯二酚基团的材料,结合近五年的国内外研究报道,介绍了含有邻苯二酚基团材料的制备方...     

抗菌生物材料的研究进展

生物材料的感染限制了生物材料的进一步应用.细菌在材料表面粘附、生长成细菌生物膜是生物材料相关感染难治的根本原因.因此,最有效的解决方法是防止细菌生物膜的形成.本文对目前抗菌生物材料的研究现状进行综述,提出目前防止细菌生物膜生成的方法主要有三种:抗细菌粘附的方法;杀菌的方法及二者相结合的方法.在设计抗粘附生物材料时,除了考虑材料表面的化学结构外,也要考虑材料的表面拓扑结构及材料的本体性能对细菌粘附的影响;在设计杀菌的生物材料时,不但要考虑杀菌性能,也要考虑杀菌剂对材料血液相容性的影响.总的来说,抗粘附的方法及杀菌相结合(多重抗菌)的方法是可望解决生物材料感染的一条新方法.     

含儿茶酚基团的湿态组织粘附水凝胶

湿态粘附作用对于生命的孕育和发展具有重要意义。水凝胶是一类兼具固液特性的智能材料，组织粘附水凝胶因多功能性和生物相容性而被广泛应用于伤口闭合和修复、细胞工程、组织工程等领域。然而，湿态组织表面的水合层阻碍了组织粘附水凝胶与组织表面形成界面粘附键。面对这一挑战，受海洋贻贝足丝蛋白中DOPA的儿茶酚基团是水下粘附的关键结构的启发，含儿茶酚基团的湿态组织粘附水凝胶的研究引起了广泛关注。本综述介绍了贻贝足丝蛋白(Mfps)的结构及湿态粘附机理，并将儿茶酚衍生物分为天然Mfps或利用基因工程合成的Mfps、含儿茶酚基团的小分子化合物、儿茶酚基团改性的天然高分子以及含儿茶酚基团的合成功能高分子；随后，概述近十年含儿茶酚基团的湿态组织粘附水凝胶在组织创口修复材料、生物涂层材料、靶向型药物输送材料、生物电子设备材料的研究进展；文末，展望了此类水凝胶材料未来发展面临的机遇和挑战。     

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。     

Molecular Engineering of Surfaces by Plasma Copolymerization and Enhanced Cell Attachment and Spreading

The plasma copolymerization of acrylic acid and methyl vinyl ketone with 1,7-octadiene is reported. A range of surfaces including hydrocarbon plasma polymer, carbonyl-containing plasma copolymer and carboxyl-containing plasma copolymers have been prepared and characterized by means of X-ray photoelectron spectroscopy. The stability of these surfaces in water has been assessed at 37°C. The influence of their functional group chemistries on the attachment and spreading of osteoblast-like (ROS 17/2.8) and bone marrow stromal cells (BMSC) has been explored. The data reported show a strong correlation between the carboxyl group and the attachment and spreading of both ROS cells and BMSC. This relationship has been explored in some detail with the ROS cells. Actin-staining by direct immunofluorescence was used to visualize changes in cytoskeleton of ROS cells with substratum chemistry. As the concentration of the carboxyl groups increased cell number and cell spreading were notably enhanced. As few as 5 carboxyls per 100 carbons were sufficient to support good attachment and with cells showing well-defined polygonal cell morphology. Although cells attached to a hydrocarbon plasma polymer surface these cells had failed to spread. The attachment and spreading of BMSC were compared on a carboxyl-containing surface and on a hydrocarbon surface. There was a more marked difference in the number of cells that had attached to these two surfaces (cf. ROS cells). The spreading on the carboxyl surface was much more typical of BMSC. Results from an extended culture using primary cultures of bone marrow cells (BMC) are reported. These cells were not trypsinized and appear to be less sensitive to differences in surface chemistry (cf. BMSC). Even so, the results at 10 days indicate much greater biosynthetic activity on the carboxyl-containing surface.     

Biofouling potentials of microporous polysulfone membranes containing a sulfonated polyether-ethersulfone/polyethersulfone block copolymer: correlation of membrane surface properties with bacterial attachment

Multivariate methods were used to identify relationships between bacterial attachment (biofouling potential), water transport, and the surface properties of nine modified polysulfone (MPS) membranes comprising blends of polysulfone (PS) with a sulfonated polyether-ethersulfone/polyethersulfone block copolymer. The topology of the microporous MPS membranes, including surface roughness, surface height, pore size and pore geometry were determined by atomic force microscopy (AFM) and digital image analysis. Other measurements included relative surface hydrophobicity by captive bubble contact angle, surface charge (i.e., degree of sulfonation) by uranyl cation binding, wt% solids, porosity, membrane thickness, water flux, and the affinity of membranes for a hydrophilic Flavobacterium and hydrophobic Mycobacterium species. The mycobacteria attached best to the MPS membranes, but the attachment of both organisms was inversely correlated with the mean aspect ratio of pores, suggesting that irregular or elliptic pores discouraged attachment. Multivariate regression analyses identified the pore mean aspect ratio, mean surface height, PS content, and the n-methylpyrrolidone+propionic acid (NMP–PA) solvent concentration as influential factors in Mycobacterium attachment, whereas membrane thickness, surface roughness, pore mean aspect ratio, porosity, and the mean pore area/image area ratio influenced Flavobacterium attachment. Cluster analyses revealed that Mycobacterium attachment was associated with hydrophobic determinants of the MPS membranes, including PS content, wt% solids, and air bubble contact angle. In contrast, Flavobacterium attachment was primarily associated with membrane thickness and charge (i.e., uranyl cation binding or degree of sulfonation). Membrane flux was inversely correlated with surface hydrophobicity and PS content, but (in contrast to cell attachment) positively correlated with most pore geometry parameters including the mean aspect ratio, suggesting that pore geometry can be optimized to minimize cell attachment and maximize water transport. Other variables influencing water flux included the NMP–PA solvent concentration and membrane roughness. The results should facilitate the design of novel microporous PS membranes having reduced biofouling potentials and greater water fluxes.     

Polystyrene film-coated glassware: a new means of reducing metal losses in trace metal speciation

A recently developed process for coating a glass surface with polystyrene (PS) film, by use of a simple chemical process has been used to reduce trace metal adsorption by cell components. The glass coating is a two-step procedure consisting of covalent attachment of vinyl-terminated PS to Si atoms on the glass surface then adsorption of PS from solution to create a stable PS film. To assess the quality of the coating we used anodic stripping voltammetry to study the adsorption of lead and cadmium ions in coated and untreated glass cells. In both short and long-term (24 h) experiments we observed that the amount of metal adsorbed was considerably less for the PS film-coated glass cell than for the uncoated cell. Further experiments showed that metal desorption is faster and metal contamination after cleaning is significantly lower for the coated cells. The PS film was, moreover, stable over a period of 6 months within the pH range 3.5–9.     

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.     

Comparison of the effect of excimer laser irradiation and RF plasma treatment on polystyrene surface

Polystyrene (PS) samples were treated with excimer laser, argon and oxygen plasmas. The surface of PS was irradiated using ArF excimer pulsed laser (λ=193 nm). Radio frequency glow discharge (RF) was used to generate the argon and oxygen plasmas. The samples were processed at different number of pulses and treatment times. The changes were characterized by atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), scanning electron microscopy (SEM) and contact angle measurements. The data from ATR-FTIR spectra showed the induction process of oxygen-based functional group in both PS samples treated with RF plasma and laser. AFM and SEM observations demonstrated that a specific nanostructure was created on the laser-treated PS surface. Contact angle measurement indicated higher wettability of the treated PS with both argon and oxygen plasmas and lesser wettability of laser-treated samples. The data from in vitro assays showed the significant cell attachment and growth onto plasma-treated surfaces in comparison with laser treated samples.     

Control of endothelial cell adhesion to polymer surface by ion implantation

The bio‐compatibility of ion implanted polymers has been studied by means of in vitro attachment measurements of bovine aorta endothelial cells. The specimens used were polystyrene (PS), polyethylene (PE), polypropylene (PP) and expanded polytetrafluoroethylene (ePTFE). He⁺ and Ne⁺ ion implantation were performed at an energy of 150 keV with fluences between 1 × 10 ¹³ to 1 × 10 ¹⁷ ions/cm ² at room temperature. Wettability was estimated by means of a sessile drop method. The chemical and physical structures of ion implanted polymers were investigated by contact angle measurements, atomic force microscopy and X‐ray photoelectron spectroscopic analysis in relation to cell attachment behavior. The strength of cell attachment on ion implanted specimens at static and under flow conditions was also measured. Ion implanted PP and ePTFE were found to exhibit remarkably higher adhesion and spreading of endothelial cells than non‐implanted specimens. In contrast to these findings, ion implanted PS and PE only demonstrated a little improvement of cell adhesion in this assay. Copyright © 2001 John Wiley & Sons, Ltd.     

Fabrication and chemical surface modification of nanoporous silicon for biosensing applications

In this work, porous silicon (PS) films with varied porosity (68–82%) were formed on the p-type, boron-doped silicon wafer (100) by the electrochemical anodisation in an aqueous hydrofluoric acid and isopropyl alcohol solution at different current densities (I _d) ranging from 20–70 mA cm^?2, respectively. Biofunctionalisation of the PS surface was carried out by chemically modifying the surface of PS by the deposition of 3-aminopropyltriethoxysilane thermally leading to high density of amine groups covering the PS surface. This further promotes the immobilisation of immunoglobulin (human IgG and goat anti-human IgG binding) on to the PS surface. Formation of nanostructured PS and the attachment of antibody–antigen to its surface were characterised using photoluminescence (PL), Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy techniques, respectively. The possibility of using these structures as biosensors has been explored based on the significant changes in the PL spectra before and after exposing the PS optical structures to biomolecules. These experimental results open the possibility of developing optical biosensors based on the variation of the PL position of the PL spectra of PS-based devices.     

BHK cells behaviour on laser treated polydimethylsiloxane surface

The surface of polydimethylsiloxane (PDMS) was modified using a CO2-pulsed laser to evaluate the changes in physical and biological properties of the treated surface. Attachment of anchorage dependent cells, namely baby hamster kidney (BHK) fibroblastic cells, on PDMS surface was investigated in stationary culture conditions. BHK cell adhesion and growth on the PDMS surfaces were studied using scanning electron microscopy (SEM) and optical microscopy. To evaluate the surface wettability, water drop contact angles were determined. The laser treated PDMS surfaces showed high hydrophobicity and low cell adhesion, no spreading and growth in comparison with the unmodified PDMS. It was found that both the wettability and surface structure of the PDMS surface control cell attachment and growth.     

Self-assembly of polystyrene-block-poly(ethylene oxide) copolymers at the air-water interface: is dewetting the genesis of surface aggregate formation?

Block copolymer self-assembly at the air-water interface is commonly regarded as a two-dimensional counterpart of equilibrium block copolymer self-assembly in solution and in the bulk; however, the present analysis of atomic force microscopy (AFM) and isotherm data at different spreading concentrations suggests a nonequilibrium mechanism for the formation of various polystyrene-b-poly(ethylene oxide) (PS-b-PEO) aggregates (spaghetti, dots, rings, and chainlike aggregates) at the air-water interface starting with an initial dewetting of the copolymer spreading solution from the water surface. We show that different spreading concentrations provide kinetic snapshots of various stages of self-assembly at the air-water interface as a result of different degrees of PS chain entanglements in the spreading solution. Two block copolymers are investigated: MW = 141k (11.4 wt % PEO) and MW = 185k (18.9 wt % PEO). Langmuir compression isotherms for the 185k sample deposited from a range of spreading concentrations (0.1-2.0 mg/mL) indicate less dense packing of copolymer chains within aggregate cores formed at lower spreading concentrations due to a competition between the interfacial adsorption of PEO blocks and the kinetic restrictions of PS chain entanglements. From AFM analysis of the transferred Langmuir-Blodgett films, it is clear that PS chain entanglements in the spreading solution also affect the morphological evolution of surface aggregates for both samples, with earlier structures being trapped at higher concentrations. At the highest spreading concentration for the 141k copolymer, the coexistence of long spaghetti aggregates with cellular arrays of holes, along with various transition structures, indicates that various surface aggregates evolve from networks of rims formed as a result of dewetting of the evaporating spreading solution from the water surface.     

Strands, networks, and continents from polystyrene dewetting at the air-water interface: implications for amphiphilic block copolymer self-assembly

We demonstrate that nanoscale aggregates similar to those formed via amphiphilic block copolymer self-assembly at the air-water interface, including strands, networks, and continents, can be generated by the simple spreading of PS homopolymer solutions on water. Two different PS homopolymers of different molecular weight (PS-405k, M(n) = 405?000 g mol(-1) and PS-33k, M(n) = 33?000 g mol(-1)) are spread at the air-water interface at various spreading concentrations ranging from 0.25 to 3.0 mg/mL. Aggregate formation is driven by PS dewetting from water as the spreading solvent evaporates. We propose that a high spreading concentration or a high molecular weight lead to chain entanglements that restrict macromolecular mobility in the solution, enabling the kinetic trapping of nanostructures associated with early and intermediate stages of PS dewetting. Comparison of PS-405k with a mainly hydrophobic PS-b-PEO block copolymer of similar molecular weight (PSEO-392k, M(n) = 392?000 g mol(-1), 2.0 wt % PEO) allows the effect of a relatively short surface active block on aggregate formation to be investigated. We show that whereas the PEO block is not a required component for the formation of strands and other nonglobular aggregates, it does increase the number of these aggregates at a given spreading concentration and decreases the minimum spreading concentration at which these aggregates are observed, along with decreasing the dimensions and polydispersity of specific surface features. The results provide supporting evidence for the role of PS dewetting in the generation of multiple PS-b-PEO aggregate morphologies at the air-water interface, as originally described in earlier paper from our group.