Patterning Surfaces for Controlled Platelet Adhesion and Detection of Dysfunctional Platelets

Platelets play a fundamental role in thrombus formation and in the pathogenesis of arterial thrombosis. Patterning surfaces for controlled platelet adhesion paves the way for adhesion and activation mechanisms in platelets and detection of platelet functional defects. Here, a new and simple method based on controlled polymerization of 2‐methacryloyloxyethyl phosphorylcholine (MPC) on the surface of styrene‐block‐(ethylene‐co‐butylene)‐block‐styrene (SEBS) is shown. The competition between polymerization and degradation enables platelet adhesion on SEBS to be switched on and off. The adhesive sites of the platelets can be down to single cell level, and the dysfunctional platelets can be quantitatively detected.

     

Cell Adhesion Micropatterning by Plasma Treatment of Alginate Coated Surfaces

Air plasma treatment, coupled to a masking technique, was used to promote micropatterned cell adhesion onto a cell-adhesion-resistant alginate coated surface. L-929 mouse fibroblasts were successfully confined into 50 m diameter cell-adhesive areas patterned inside a cell-resistant layer. The plasma treatment performed, albeit very mild, destroys the molecular architecture of the hydrophilic polysaccharide coating, leading to an enhancement of protein adsorption and hence of cell-adhesion. Both the cell-adhesion-resistant and the cell-adhesive regions are hydrophilic, yet they show a completely different behavior towards cells. Thus, they are a very interesting subject in the study of interfacial interactions in aqueous media, and, in particular, on the mechanisms of bio-adhesion at hydrophilic surfaces.     

血液相容生医材料的合成研究15——苯乙烯型磺酸铵内盐单体的合成及其聚合物的抗血小板粘附性能

两性离子不凝血生物材料;血液相容生医材料的合成研究15——苯乙烯型磺酸铵内盐单体的合成及其聚合物的抗血小板粘附性能     

Plasma-Induced Graft Polymerization of Poly(ethylene glycol) Methyl Ether Methacrylate on Si(100) Surfaces for Reduction in Protein Adsorption and Platelet Adhesion

Argon plasma-induced graft polymerization of a solution-coated macromonomer, poly(ethylene glycol) methyl ether methacrylate (PEGMA), on the Si(100) surface was carried out to impart anti-fouling properties to the Si(100) surface. The surface composition and microstructure of the PEGMA graft-polymerized Si(100) surfaces were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) measurements. The extent of crosslinking in the plasma-graft polymerized PEGMA (pp-PEGMA) was estimated by gel fraction determination. In general, an appropriate RF power of about 15 W and a PEGMA macromonomer concentration of about 1 wt% in the coating solution for plasma polymerization produced a high graft yield of pp-PEGMA on the Si(100) surface (the pp-PEGMA-g-Si surface). The Si(100) surface with a high concentration of the grafted pp-PEGMA was effective in preventing bovine serum albumin (BSA) adsorption and platelet adhesion.     

Cell Adhesion onto Highly Curved Surfaces: One‐Step Immobilization of Human Erythrocyte Membranes on Silica Beads

This paper deals with single‐step, orientation‐selective immobilization of human erythrocyte membranes on bare silica beads with different topographies: 1) solid (nonporous) silica beads with a diameter of 3 μm and 2) porous silica beads with a diameter of 5 μm. Erythrocyte membranes were immobilized onto beads simply by incubation, without sonication or osmotic lysis. Membrane orientation before and after immobilization was identified with two immunofluorescence labels: 1) the extracellular part of glycophorin can be labeled with a first monoclonal antibody and a second polyclonal antibody with fluorescence dyes (outside label), while 2) the cytoplasmic domain of Band 3 can be recognized with a first monoclonal antibody and a second fluorescent polyclonal antibody (inside label). Adherent erythrocytes on the beads all ruptured, inverted the asymmetric orientation of the membrane, and selectively exposed their cytoplasmic domain. The surface topography did not influence the orientation or the amount of immobilized membrane. On the other hand, the fact that no adsorption or rupture of erythrocytes could be observed on planar quartz substrates suggests a significant influence of contact curvature on adhesion energy.     

Immobilization of Magnetic Nanoparticles onto Conductive Surfaces Modified by Diazonium Chemistry

Core-shell γ-Fe(2)O(3)@SiO(2) nanoparticles (NPs) substituted by PEG and NH(2) groups may be immobilized on metal surfaces (glassy carbon or gold) substituted by 4-carboxyphenyl groups through electrostatic interactions. Such immobilization is evidenced by (i) IRRAS owing to the Si-O band, (ii) SEM images, which show that the surface coverage by the NPs is nearly 100%, and (iii) the NPs film thickness measured by ellipsometry or AFM, which corresponds to about one NPs monolayer. Such NPs film is permeable to redox probes, which allows us to propose electrochemical methods based on direct or local measurements as a way to inspect the NPs assembly steps through their ability to alter mass and charge transfer. This process also applies to patterned polystyrene surfaces, and selective immobilization of NPs substituted by amino groups was carried out onto submillimeter patterns obtained by local oxidation. Biological applications are then expected for hyperthermia activation of the NPs to trigger cellular death. Finally, some tests were performed to further derivatize the immobilized NPs onto surfaces through either a covalent bond or electrostatic interactions. Future work will be dedicated to the recovery of such Janus NPs from the substrate surface.     

材料表面性质调控细胞黏附

生物医用材料旨在通过调控材料和细胞之间的相互作用来实现组织的再生和修复。黏附过程直接决定了细胞是否能够充分发挥生物学性能,因此通过对材料表面的物理和化学改性来调控细胞黏附,对于生物材料具有至关重要的意义,也是非常活跃的研究热点。材料表面物理改性通常通过对包括表面粗糙度、形貌、模量和多孔结构等物理性质的调控,为细胞构建适合黏附的材料表面。而化学改性则借助于表面电荷及亲疏水性调控、促黏分子修饰等化学手段来提高材料表面与细胞间的相互作用力,进而促进细胞黏附。近年来,材料表面调控细胞黏附的研究取得了许多新的突破性进展。例如在传统的促黏分子表面修饰之外,人们逐步发现对促黏分子序构的精准调控也可以有效地提高材料表面的促黏性能。而刺激响应性表面则可以根据外界信号的刺激,使得材料表面在促黏和抗黏之间实现智能的转换。本文从物理改性、化学修饰、刺激响应性表面构建等角度出发,全面总结和讨论了材料表面性质对细胞黏附的调控作用,梳理了材料表面的设计思路,多种材料表面的修饰改性方法等最新进展,并展望了未来材料表面对细胞黏附的调控思路。     

CaCO3粉末表面光聚合处理的研究

采用表面光聚合技术处理CaCO₃粉末,研究了反应温度、时间、单体浓度等对丙烯酰胺(AAM)在CaCO₃粉末表面光聚合的影响,并采用X光电子能谱(ESCA)、粒度分析、扫描电子显微镜(SEM)和模型模拟分析等研究了表面光聚合处理碳酸钙(CaCO₃)的结构.结果表明:紫外光能有效地引发AAM在CaCO₃粒子表面聚合.经光聚合处理后,CaCO₃粒子表面形成了聚丙烯酰胺(PAAM)包覆层,该包覆层与CaCO₃粒子结合紧密,不能被溶剂洗涤清除.光聚合处理后CaCO₃粒子表面较光滑,分散性可得到提高,CaCO₃粒子粒径增大.     

利用表面上的小分子控制细胞黏附

细胞黏附是重要的生理过程,多细胞生物体中大部分种类的细胞都依赖于在表面的黏附而进行其正常生理活动。细胞的黏附需要固定在表面的有机分子（例如蛋白质或多肽）作配体。我们利用表面小分子模拟蛋白质或多肽作为配体,通过与细胞膜上受体结合,促进细胞黏附到表面。聚乙二醇（PEG）可以抵抗细胞在表面的黏附,我们利用含有PEG的表面小分子来调节细胞黏附。细胞表面的受体与胞外基质表面的配体结合是一个动态过程,在适宜时间和空间发生的时候,细胞就会产生运动和迁移,细胞的迁移也是重要的生理过程。本文主要介绍近年来利用小分子的表面化学和微纳米结构控制细胞在表面的黏附和迁移。     

铝合金表面改性对有机涂层附着力的影响及腐蚀防护性能研究

利用电化学阻抗（EIS）、扫描微参比技术（SRET）、接触角、粗糙度、附着力、盐雾等测试方法,研究了铝合金阳极氧化与贻贝黏附蛋白（MAP）/CeO₂/硅烷γ-APS（MCA）表面复合修饰的腐蚀防护性能以及对改性聚氨酯涂层附着力和耐蚀性的影响。结果表明,MCA复合膜可抑制铝合金的腐蚀,并具有一定的自修复功能;阳极氧化和MCA表面复合修饰可为铝合金提供有效的早期腐蚀防护作用,且能提高铝合金表面粗糙度和润湿性,显著提升改性聚氨酯涂层在铝合金表面的附着力和耐蚀性,因而结合改性聚氨酯涂层和表面复合修饰可实现对铝合金长期有效的腐蚀防护。     

SUPPRESSION OF CELL ADHESION ON POLYACRYLONITRILE-BASED MEMBRANES BY THE ANCHORING OF PHOSPHOLIPID MOIETIES

In this work, the membrane surface of poly（acrylonitrile-co-2-hydroxyethyl methacrylate） （PANCHEMA） was chemically modified by anchoring of phospholipid moieties. The process involved the reaction of hydroxyl groups on the membrane surface with 2-chloro-2-oxo-1,3,2-dioxaphospholane （COP） followed by the ring-opening reaction of COP with trimethylamine. Chemical differences between the original and the modified membranes were characterized by FT-IR and XPS, It was found that the amount of macrophage adhered on the modified membrane surface is substantially lower than that on polyacrylonitrile （PAN） and PANCHEMA membranes under the same condition, The morphological change of the adherent cell is also suppressed by the generation ofphospholipid moieties on the membrane surface.     

Investigations on the Stability of Plasma Modified Silicone Surfaces

In this work it was investigated the effect of the exposure to different plasmas on the wettability of silicone samples. We have observed that oxygen. argon, and hydrogen glow discharges are quite effective in reducing the water contact angle of such polymer. However, indifferently to efficiency of the treatment, practically all the modified surfaces recovered great part of their original hydrophobicity. We have investigated this hydrophobic recovery using surface energy measurements and theoretical simulations based on the exponential decay of the population of polar groups on the surface. According to our results such recovery can be attributed to the decrease of polar species at the interface water–polymer surface.     

Bifunctional Adhesion Promoter for Grafting Polypyrrole Films on Metal/Metal Oxide Surfaces

A new class of pyrrole derivatives, ω-[(3-phenyl) pyrrol-1-yl] alkyl phosphonic acids with long chains of 10 and 12 carbon atoms were synthesised to graft polypyrrole layers on metal/metal oxide surfaces. These compounds are bifunctional containing two reactive moieties, pyrrole as the polymerisable group and phosphonic acid as the anchoring group. Contact angle measurements and X-ray photoelectron spectroscopy (XPS) confirmed adsorption with phosphonic acid group attached to the surface. Surface plasmon resonance (SPR) spectroscopy indicated that adsorption starts in seconds and is completed in few hours. Adsorption is followed by surface induced polymerisation with further monomer. We obtained dense and homogeneous polypyrrole films, which were characterised for their morphology and thickness by atomic force microscopy (AFM). The derivatives form a strongly bonded composite of metal with polymer.     

PNIPAAm改性表面对蛋白质吸附的调控及其应用

根据不同领域的需要,控制蛋白质在材料表面的吸附是一个具有重要应用价值的课题。聚（N-异丙基丙烯酰胺）（PNIPAAm）改性表面能够响应外界温度变化从而改变其表面性质,这一特点为调控蛋白质的吸附提供了可能。近年来,研究者们应用多种表征方法考察了不同温度下蛋白质在PNIPAAm改性表面的吸附,并试图从分子水平上深入理解其吸附机制及影响因素。本文综述了近年来应用PNIPAAm改性表面对蛋白质吸附的研究及其最新进展。发现当PNIPAAm层厚度处于一定范围内时,PNIPAAm改性表面表现出对蛋白质吸附的温度敏感性,并可以利用这一性质将其应用于蛋白质纯化及分离和生物传感器等领域。而当PNIPAAm层厚度超过一个临界值时,PNIPAAm改性表面表现出良好的阻抗血浆蛋白质的性质,使其有望在血液相容性表面领域得到应用。最后,就PNIPAAm改性表面调控蛋白质吸附的未来发展方向简要地进行了展望。     

Potential‐Responsive Surfaces for Manipulation of Cell Adhesion,Release, and Differentiation

In living systems, interfacial molecular interactions control many biological processes. New stimuli‐responsive strategies are desired to provide versatile model systems that can regulate cell behavior in vitro. Described here are potential‐responsive surfaces that control cell adhesion and release as well as stem cell differentiation. Cell adhesion can be modulated dynamically by applying negative and positive potentials to surfaces functionalized with tailored monolayers. This process alters cell morphology and ultimately controls behavior and the fate of the cells. Cells can be detached from the electrode surface as intact clusters with different geometries using electrochemical potentials. Importantly, morphological changes during adhesion guide stem cell differentiation. The higher accessibility of the peptide under a positive applied potential causes phenotypic changes in the cells that are hallmarks of osteogenesis, whereas lower accessibility of the peptide promoted by negative potentials leads to adipogenesis.     

仿生沉积法制备水下低气体黏附透明材料

透明材料常用于水下设备中,而聚合物透明材料多较为疏水,在水下易黏附气泡,影响其光学性能.利用多巴胺(DA)和聚乙烯亚胺(PEI)共沉积技术,在多种透明聚合物材料表面构建了亲水/水下超疏气涂层.结果表明,聚多巴胺(PDA)与PEI可通过Michael加成或Schiff碱反应在此类材料表面形成亲水交联网络,显著提高其表面亲水性.表现为水接触角显著降低,而水下气接触角显著提高(140?),气泡在材料表面的黏附力显著下降.沉积时间在6 h以下时,XPS和椭圆偏振测试的结果表明,虽然所选用的透明材料表面沉积量和沉积厚度随时间有所上升,但其透光性不会受到显著影响.该方法具有较强的普适性,可用于多种水下气体黏附性较强的透明高分子材料,如聚苯乙烯(PS)、聚对苯二甲酸乙二醇酯(PET)、聚甲基丙烯酸甲酯(PMMA)、聚丙烯(PP)和聚酰亚胺(PI)等.同时,该方法形成的涂层的长期稳定性也较好,材料在水中浸泡振荡10天之后仍能保持较好的抗气泡黏附能力.该方法适用于如潜水艇舷窗、护目镜、水下光学镜头及其防护罩等水下设备中.     

A Comparison of PE Surfaces Modified by Plasma Generated Neutral Nitrogen Species and Nitrogen Ions

The surface modification of polyethylene (PE) by neutral nitrogen species (ground and excited state N₂ as well as atomic N; modified nitrogen plasma treatment) has been compared to the effect of nitrogen ion bombardment using X-ray Photoelectron Spectroscopy (XPS) and contact angle measurements. XPS results indicate that a greater nitrogen concentration was grafted during the modified nitrogen plasma treatment of PE, an effect that was attributed to surface sputtering during ion beam modification. The distribution of nitrogen-containing functionalities was strongly dependent upon the treatment strategy; the modified nitrogen plasma treatment lead predominantly to imine groups being formed at the PE surface, while amine groups were the dominant species produced during ion beam modification. The presence of electron irradiation during the modified nitrogen plasma treatment of PE did not modify the rate of nitrogen incorporation or change the nature of N-containing functional groups produced but did lead to a systematic decrease in contact angle.     

Synthesis and Characterization of New Adhesion Promoter for Grafting Conducting Polymer on Oxide Substrate

For grafting polypyrrole layers on oxidic substrates, the synthesis and characterization of a new adhesion promoter 11‐(pyrrol‐3‐yl) undecyl trimethoxysilane (PyTMS) were described in this article. The oxidation potential of PyTMS was determined by cyclic voltammetry. The grafting behavior of such an adhesion promoter on oxidized surface and chemical deposition of polypyrrole over the modified oxidized surface were studied. The adsorbed layer on the oxidized substrates thus formed was determined by both contact angle measurements and X‐ray photoelectron spectroscopy. Chemical polymerization of terminal pyrrole moieties on such substrates yielded adhesive polypyrrole films, and SEM image showed that the morphology of the polypyrrole films was influenced by the experimental conditions.     

低黏附耐酸碱水相超疏油铜表面的制备

制备了一种新型的耐酸碱性的水相超疏油铜表面. 在水相中,油滴在其表面上的接触角高达162°,同时极易滚动,表明所得到的表面不但具有水相超疏油特性,同时还表现出较低的黏附性及较强的耐酸碱能力. 在不同pH值（2~12）的水溶液中,这种低黏附超疏油特性依然存在. 研究表明,该表面的水下超疏油及低黏附特性主要源于表面亲水性的化学组成及独特的微纳米等级结构之间的协同作用. 而较强的耐酸碱性则得益于铜材料自身较好的化学稳定性.     

两性离子自组装仿生表面的制备、 表征及抗黏附性能

设计与合成了磺酸甜菜碱型的两性离子化合物: N,N-二甲基氨甲酸乙酯基丙基三乙氧基硅烷磺酸内盐(SiNNS), 利用红外光谱(FTIR)和氢核磁共振波谱(¹H NMR)对其分子组成与结构进行了表征. 通过自组装技术将SiNNS分子构筑在玻璃基材表面, 形成了模拟细胞外层膜的仿生表面. 利用原子力显微镜(AFM)、 X光电子能谱(XPS)和接触角测量仪对表面的形貌特征、 化学组成和润湿性进行了表征. 以空白玻璃为对照样品, 研究了这一表面的防雾性能和抗细菌黏附性能. 结果表明, 所制备的两性离子自组装仿生表面具有超亲水性和水下超疏油特性, 其水滴接触角为9.2°, 水下油滴接触角接近180°; 与对照样品相比, 两性离子自组装表面具有优异的防雾性与抗细菌黏附性.