医用聚氯乙烯膜的等离子体表面改性

用两种不同气氛的辉光放电等离子体工艺对医用软质聚氯乙烯（ＰＶＣ）膜进行了表面改性研究。结果表明，聚合性气氛的等离子体改性效果明显优于非聚合性气氛。平整致密的聚合膜对ＰＶＣ增塑剂——邻苯二甲酸二辛酯的迁移和扩散起了阻挡作用，也使膜表面亲水性和表面张力极性成份增大，液固相界面张力减小，生物相容性得以改善。     

Adhesion Aspects of Plasma Polymerized Acetonitrile and Acrylonitrile on Polypropylene Surface

Acetonitrile and acrylonitrile were plasma polymerized on Polypropylene (PP) surface. Surface modifications were characterized by surface energy measurements and ATR-FTIR spectroscopy. Surface energy measurement showed incorporation of hydrophilic groups along with deposition of cross-linked network of plasma-polymerized product. ATR-FTIR analysis of modified films showed incorporation of conjugated imine and amine groups. Using change in the relative intensities of C—H stretch bands of polypropylene surface, site of attachment of hydrophilic group and most predominant surface chemical reaction could be inferred. Chemical nature of plasma polymerized product was studied using FTIR by KBr disc method. Adhesion test was performed on modified surface by peel test method. Surface energy and peel strength measurements were performed for the samples aged for 2 months in order to check the durability of surface modification.     

Plasma surface modification of chitosan membranes: characterization and preliminary cell response studies

Surface modification of biomaterials is a way to tailor cell responses whilst retaining the bulk properties. In this work, chitosan membranes were prepared by solvent casting and treated with nitrogen or argon plasma at 20 W for 10-40 min. AFM indicated an increase in the surface roughness as a result of the ongoing etching process. XPS and contact angle measurements showed different surface elemental compositions and higher surface free energy. The MTS test and direct contact assays with an L929 fibroblast cell line indicated that the plasma treatment improved the cell adhesion and proliferation. Overall, the results demonstrated that such plasma treatments could significantly improve the biocompatibility of chitosan membranes and thus improve their potential in wound dressings and tissue engineering applications.     

Surface modification of titanium by using plasma‐induced graft‐polymerization

Plasma‐induced graft‐polymerization (PIGP) method was utilized in this study to improve corrosion behavior and biocompatibility of titanium (Ti) surface. Bioactive molecule polyacrylamide (PAM) was immobilized onto Ti surface by introducing silanederivatized spacer arms as an intermediary for the covalent linkage. Ti was firstly activated by O₂ plasma, and oxygen‐containing groups were introduced on its surface consequently. The intermediary mercapto silane spacer molecules were then covalently linked to the oxidated surface, followed by the covalent binding of PAM and the sulfhydryl‐terminal groups via PIGP. Surface analyses following modification process included water contact angles (CA), SEM, attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), XPS and atomic force microscope (AFM). The results revealed the effectiveness of this method on immobilizing PAM to Ti surface, and the hydrophilicity of modified surface improved remarkably. In addition, potentiodynamic polarization and cellular proliferation tests were implemented to validate the enhanced corrosion‐resistance and biocompatibility of modified Ti surface, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Silicate-Phenolic Networks: Coordination-Mediated Deposition of Bioinspired Tannic Acid Coatings

Surface modification with polyphenolic molecules has been pursued in biomedical materials owing to their antioxidant, anti-inflammatory, and antimicrobial characteristics. Recently, the use of silicic acid (Si_aq) as a mediator for efficient surface deposition of tannic acid (TA) was reported, but the postulated Si-TA polymeric networks were not characterized. Herein, we present unambiguous evidence for silicate-TA networks that involve Si−O−C motifs by using solid-state NMR spectroscopy, further supported by XPS and ToF-SIMS. By using QCM-D we demonstrate the advantages of Si_aq, compared to using transition-metal ions, to improve the coating efficiency under mildly acidic conditions. The presented homogenous coating buildup and validated applicability in inorganic buffers broadens the use of TA for surface modifications in technological and biomedical applications.     

Surface modification of biomedical polymers

Surface modification of biomedical polymers by the technique of surface grafting was briefly overviewed, mostly based on our results. It was shown that surface grafting of water-soluble polymer chains onto polymeric biomaterials was effective in producing mechanically non-stimulative, blood-compatible, antibacterial, tissue-bonding, and cell-adhesive surfaces. In addition to the improvement of the interfacial biocompatibility, the surface grafting was useful also for obtaining a biofunctional surface such as immunoadsorbent.     

羟基磷灰石表面改性的研究进展

羟基磷灰石（HAP）由于其良好的生物相容性及骨诱导作用而被广泛应用于生物复合材料中。但是,其本身容易聚集,与聚合物之间相容性差,会导致复合材料的力学性能和生物学性能下降。在HAP表面改性既可以有效防止颗粒间的聚集,增强其与基体间的相互作用,同时,还可以通过接上具有特殊功能的聚合物,赋予HAP新的用途。本文综述了羟基磷灰...     

Increasing the Hydrophobicity of a PP Film Using a Helium/CF<Subscript>4</Subscript> DBD Treatment at Atmospheric Pressure

Plasma surface modification is widely used to tailor the surface properties of polymeric materials. Most treatments are performed using low pressure plasma systems, but recently, atmospheric dielectric barrier discharges (DBDs) have appeared as interesting alternatives. Therefore, in this paper, an atmospheric He + CF₄ DBD is used to increase the hydrophobicity of a polypropylene (PP) film. The surface characterization of the PP film is performed using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results show that the hydrophobic properties of the polymer films are greatly enhanced after plasma treatment as evidenced by an increased contact angle. The incorporation of fluorine on the surface is significant (45 at%), demonstrating the ability of the used DBD set-up to generate fluorine-containing functional groups on the PP surface.     

Plasma Surface Modification of Biomedical Polymers: Influence on Cell-Material Interaction

Polymers are commonly used in industry because of their excellent bulk properties, such as strength and good resistance to chemicals. Their surface properties are for most application inadequate due to their low surface energy. A surface modification is often needed, and plasma surface modification is used with success the past decades. In the past few years, also plasma surface modification for biomedical polymers has been investigated. For biomedical polymers, the surface properties need to be altered to promote a good cell adhesion, growth and proliferation and to make them suitable for implants and tissue engineering scaffolds. This review gives an overview of the use of plasma surface modification of biomedical polymers and the influence on cell-material interactions. First, an introduction on cell-material interaction and on antibacterial and antifouling surfaces will be given. Also, different plasma modifying techniques used for polymer surface modification will be discussed. Then, an overview of literature on plasma surface modification of biopolymers and the resulting influence on cell-material interaction will be given. After an overview of plasma treatment for improved cell-material interaction, plasma polymerization and plasma grafting techniques will be discussed. Some more specialized applications will be also presented: the treatment of 3D scaffolds for tissue engineering and the spatial control of cell adhesion. Antibacterial and antifouling properties, obtained by plasma techniques, will be discussed. An overview of research dealing with antibacterial surfaces created by plasma techniques will be given, antifouling surfaces will be discussed, and how blood compatibility can be improved by preventing protein adhesion.     

Surface Energy and Adhesive Properties of Polyamide 12 Modified by Barrier and Radio-Frequency Discharge Plasma

Summary. The polyamide 12 foil with sufficient surface and adhesive properties to other substrates can be prepared by discharge plasma modification. For improvement of bonding and printing of polymer a surface barrier discharge plasma in N₂ and O₂ as well as a radio-frequency discharge plasma in air has been studied. A significant increase in surface energy of the polymer as well as in strength of adhesive joint to more polar polymer was found. The chemical changes of PA 12 modified by plasma were analyzed using fourier transform infra red – attenuated total reflection (FTIR–ATR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. The observed changes of surface properties of the polymer due to aging were not important.     

Surface Energy and Adhesive Properties of Polyamide 12 Modified by Barrier and Radio-Frequency Discharge Plasma

The polyamide 12 foil with sufficient surface and adhesive properties to other substrates can be prepared by discharge plasma modification. For improvement of bonding and printing of polymer a surface barrier discharge plasma in N₂ and O₂ as well as a radio-frequency discharge plasma in air has been studied. A significant increase in surface energy of the polymer as well as in strength of adhesive joint to more polar polymer was found. The chemical changes of PA 12 modified by plasma were analyzed using fourier transform infra red – attenuated total reflection (FTIR–ATR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. The observed changes of surface properties of the polymer due to aging were not important.     

Polyelectrolyte Adsorption on NH3-Plasma-Treated Poly(tetrafluoroethylene-co-hexafluoropropylene)

A two-step procedure for a permanently hydrophilic surface modification of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP, fluorinated ethylene propylene) was studied. In the first step a cationic polymer surface was created by low-pressure ammonia plasma treatment introducing nitrogen-containing functional groups. Afterwards, the anionic poly(sodium 4-styrenesulfonate) was adsorbed onto the plasma-treated FEP surface. The adsorption was assumed to be controlled by ionic interactions. The modification effects and their long-term behavior were evaluated by means of water contact angle goniometry. Furthermore, electrokinetic measurements and X-ray photoelectron spectroscopy were used for surface characterization.     

Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

Surface modification with dielectric barrier discharge (DBD) plasma was carried out at atmospheric pressure (argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens (IOL). Changes of the plasma-treated IOL surface in chemical composition, morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and water contact angle (WCA) measurements. The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets, macrophages and lens epithelial cells (LECs) in vitro. After DBD plasma treatment, the hydrophilicity of the IOL surface was obviously improved. The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect. The existence of low molecular weight oxidized material (LMWOM) was proved on the plasmatreated IOL which was caused by the chain scission effect of the plasma treatment. The plasma-treated IOLs resisted the adhesion of platelets and macrophages significantly. The LECs spreading and proliferation were postponed on the IOLs plasma-treated for more than 180 s, with a well maintained epithelial phenotype of LECs. The IOL biocompatibility was improved after the DBD plasma treatment. We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification (ACO) may be expected after implantation of the argon DBD plasma-treated IOL. Supported by the Zhejiang Natural Science Foundation of China (Grant No. 2004C23003)     

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。     

Surface modification of poly(dimethylsiloxane) with a perfluorinated alkoxysilane for selectivity toward fluorous tagged peptides

Poly(dimethylsiloxane) (PDMS) and similar polymers have proved to be of widespread interest for use in microfluidic and similar microanalytical devices. Surface modification of PDMS is required to extend the range of applications for devices made of this polymer, however. Here we report on the grafting of perfluorooctyltriethoxysilane via hydrolysis onto an oxidized PDMS substrate in order to form a fluorinated microchannel. Such a fluorinated device could be used for separating fluorous tagged proteins or peptides, similar to that which has been recently demonstrated in a capillary electrophoresis system or in an open tubular capillary column. The modified polymer is characterized using chemical force titrations, contact angle measurements, and X-ray photoelectron spectroscopy (XPS). We also report on a novel means of performing electroosmotic measurements on this material to determine the surface zeta potential. As might be expected, contact angle and chemical force titration measurements indicate the fluorinated surface to be highly hydrophobic. XPS indicates that fluorocarbon groups segregate to the surface of the polymer over a period of days following the initial surface modification, presumably driven by a lower surface free energy. One of the most interesting results is the zeta potential measurements, which show that significant surface charge can be maintained across a wide range of pH on this modified polymer, sufficient to promote electroosmotic flow in a microfluidic chip. Matrix-assisted time-of-flight mass spectrometry (MALDI-TOF MS) measurements show that a fluorous-tagged peptide will selectively adsorb on the fluorinated PDMS in aqueous solution, demonstrating that the fluorinated polymer could be used in devices designed for the enrichment or enhanced detection of fluorous-labeled proteins and peptides.     

Surface modification of a titanium alloy with a phospholipid polymer prepared by a plasma-induced grafting technique to improve surface thromboresistance

To improve the thromboresistance of a titanium alloy (TiAl₆V₄) surface which is currently utilized in several ventricular assist devices (VADs), a plasma-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) was carried out and poly(MPC) (PMPC) chains were covalently attached onto a TiAl₆V₄ surface by a plasma induced technique. Cleaned TiAl₆V₄ surfaces were pretreated with H₂O-vapor-plasma and silanated with 3-methacryloylpropyltrimethoxysilane (MPS). Next, a plasma-induced graft polymerization with MPC was performed after the surfaces were pretreated with Ar plasma. Surface compositions were verified by X-ray photoelectron spectroscopy (XPS). In vitro blood biocompatibility was evaluated by contacting the modified surfaces with ovine blood under continuous mixing. Bulk phase platelet activation was quantified by flow cytometric analysis, and surfaces were observed with scanning electron microscopy after blood contact. XPS data demonstrated successful modification of the TiAl₆V₄ surfaces with PMPC as evidenced by increased N and P on modified surfaces. Platelet deposition was markedly reduced on the PMPC grafted surfaces and platelet activation in blood that contacted the PMPC-grafted samples was significantly reduced relative to the unmodified TiAl₆V₄ and polystyrene control surfaces. Durability studies under continuously mixed water suggested no change in surface modification over a 1-month period. This modification strategy shows promise for further investigation as a means to reduce the thromboembolic risk associated with the metallic blood-contacting surfaces of VADs and other cardiovascular devices under development.     

Surface modification and characterization of magnetic polymer nanospheres prepared by miniemulsion polymerization

A novel and effective protocol for the surface modification and quantitative characterization of magnetic polymeric nanospheres prepared by miniemulsion polymerization is reported. Composite nanospheres consisting of polymer-coated iron oxide nanoparticles were prepared by the miniemulsion polymerization of methyl methacrylate and divinylbenzene in the presence of magnetic fluid. Surface modification reaction of the magnetic polymer with poly(ethylene glycol) (PEG) was employed to obtain a hydrophilic hydroxyl-group-functionalized magnetic nanospheres. An affinity dye, Cibacron blue F3G-A (CB), was then coupled covalently to prepare a magnetic nonporous affinity adsorbent. The morphology and magnetic property of the polymer nanospheres obtained were examined by transmission electron microscopy and a vibrating sample magnetometer. The contents of surface groups modified were quantitatively measured by using diffusive reflectance Fourier transform infrared spectroscopy on the basis of a linear relationship between the intensity ratio of IC-O-C/IC=O and the content of PEG. X-ray photoelectron spectroscopy (XPS) was used to examine the surface of magnetic nanospheres. It was confirmed by the comparison of XPS spectra of both dye-coated and uncoated magnetic nanospheres to which the CB ligand was coupled, and the surface of the PEG-modified nanospheres had an exact 3:7 atomic ratio of sulfur to nitrogen.     

Multitechnique surface spectroscopic studies of plasma modified polymers III. H2O and O2/H2O plasma modified poly(methyl methacrylate)s

The surfaces of poly(methyl methacrylate) (PMMA) films modified by O₂H₂O and H₂O radio-frequency glow discharge plasmas were studied using electron spectroscopy for chemical analysis (ESCA or XPS), low energy ion scattering (LEISS or ISS), Fourier transform IR spectroscopy (FTIR) with attenuated total reflectance (ATR) sampling, and critical surface energy from contact angle measurements. The extent and nature of modification with respect to promotion of a hydrophilic surface compared to the hydrophobic surface of the unmodified PMMA has been probed. Results show drastic decreases in C/O ratio at the near surface, which increases to that of the unmodified PMMA as deeper cross sections are analyzed. In addition peak fitting of ESCA data correlated with FTIR functional group information allows for the qualitative and quantitative analysis of the resulting bonding and structure of the modified layer. From these results combined with the polarity and surface energy differences obtained from contact angle measurements, the structural changes are discussed with respect to plasma reaction mechanisms and differences in the structure of the modified polymer films.     

Adhesion Enhancement and Characterization of Plasma Polymerized 1,2-Dichloroethane on Polypropylene Surface

Polypropylene (PP) films were modified in 1,2-dichloroethane (DCE) plasma. Surface energy measurement and rate of deposition showed two-step surface modification. First, incorporation of chloride ions on PP surface followed by deposition of cross-linked layer. DCE plasma modified PP films were subsequently compared with earlier reported work on carbontetrachloride (CCl₄) and chloroform (CHCl₃) plasma modification. Modified films were characterized using ATR-FTIR technique by monitoring the relative changes in intensities of C–H stretch vibrations. The nature of deposition on PP film was characterized using FTIR technique and solubility test. Peel strength measurements of DCE, CCl₄, and CHCl₃ plasma modified films showed improvement in bonding strength. Durability of plasma modified PP film was studied by calculating surface energy and peel strength of samples aged for two months.     

Evaluation and Improvement of the Stability of Poly(ethylene oxide)-based Solid-state Batteries with High-Voltage Cathodes

Solid-state batteries (SSBs) with high-voltage cathode active materials (CAMs) such as LiNi_1−x−yCo_xMn_yO₂ (NCM) and poly(ethylene oxide) (PEO) suffer from “noisy voltage” related cell failure. Moreover, reports on their long-term cycling performance with high-voltage CAMs are not consistent. In this work, we verified that the penetration of lithium dendrites through the solid polymer electrolyte (SPE) indeed causes such “noisy voltage cell failure”. This problem can be overcome by a simple modification of the SPE using higher molecular weight PEO, resulting in an improved cycling stability compared to lower molecular weight PEO. Furthermore, X-ray photoelectron spectroscopy analysis confirms the formation of oxidative degradation products after cycling with NCM, for what Fourier transform infrared spectroscopy is not suitable as an analytical technique due to its limited surface sensitivity. Overall, our results help to critically evaluate and improve the stability of PEO-based SSBs.