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1.
In the present study, we have utilized X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (ELM), and optical waveguide lightmode spectroscopy (OWLS) to examine the surface adsorption and protein resistance behavior of bio-inspired polymers consisting of poly(ethylene glycol) (PEG) conjugated to peptide mimics of mussel adhesive proteins. Peptides containing up to three residues of 3,4-dihydroxyphenylalanine (DOPA), a key component of mussel adhesive proteins, were conjugated to monomethoxy-terminated PEG polymers. These mPEG-DOPA polymers were found to be highly adhesive to TiO2 surfaces, with quantitative XPS analysis providing useful insight into the binding mechanism. Additionally, the antifouling properties of immobilized PEG were reflected in the excellent resistance of mPEG-DOPA-modified TiO2 surfaces to protein adsorption. Measurements of mPEG-DOPA and human serum adsorption were related in terms of ethylene glycol (EG) surface density and serum mass adsorbed and demonstrated a threshold of approximately 15-20 EG/nm2, above which substantially little protein adsorbs. With respect to surface density of adsorbed PEG and the associated nonfouling behavior of the adlayers, strong parallels exist between the nonfouling properties of the surface-bound mPEG-DOPA polymers and PEG polymers immobilized to surfaces using other approaches. Peptide anchors containing three DOPA residues resulted in PEG surface densities higher than those achieved using several existing PEG immobilization strategies, suggesting that peptide mimics of mussel adhesive proteins may be useful for achieving high densities of protein-resistant polymers on surfaces.  相似文献   

2.
We have developed surfaces for the selective presentation of biotinylated peptides and proteins in a background that resists nonspecific protein adsorption; controlled amounts of biotinylated poly(ethylene glycol) (MW 3400 Da; PEG3400) anchored to titanium-dioxide-coated surfaces via an adhesive tri-peptide sequence of L-3,4-dihydroxyphenylalanine (DOPA3-PEG3400-biotin; DPB) were incorporated within a DOPA3-PEG2000 background. Using optical waveguide lightmode spectroscopy, we found that the amounts of sequentially adsorbed NeutrAvidin and singly biotinylated molecules increased proportionally with the amount of DPB in the surface. Biotinylated peptides (MW approximately 2000 Da) were able to fill all three of the remaining avidin-binding sites, while only one molecule of biotinylated PEG5000 or stem cell factor bound to each avidin. The resulting biotin-avidin-biotin linkages were stable for prolonged periods under continuous perfusion, even in the presence of excess free biotin. Hematopoietic M07e cells bound to immobilized peptide ligands for alpha5beta1 (cyclic RGD) and alpha4beta1 (cylic LDV) integrins in a DPB-dose-dependent manner, with near-maximal binding to cylic LDV for surfaces containing 1% DPB. Multiple ligands were adsorbed in a controlled manner by incubating NeutrAvidin with the respective ligands in the desired molar ratio and then adding the resulting complexes to DPB-containing surfaces. Cell adhesion to surfaces containing both cylic LDV and cyclic RGD increased in an additive manner compared to that for the individual ligands. The bioactivity of adsorbed biotinylated stem cell factor was retained, as demonstrated by DPB-dose-dependent M07e cell adhesion and ERK1/2 activation.  相似文献   

3.
Artificial small‐caliber vascular grafts are still limited in clinical application because of thrombosis, restenosis, and occlusion. Herein, a small‐caliber vascular graft (diameter 2 mm) is fabricated from poly(ε‐caprolactone)‐b‐poly(isobutyl‐morpholine‐2,5‐dione) (PCL‐PIBMD) and silk fibroin (SF) by electrospinning technology and then biofunctionalized with low‐fouling poly(ethylene glycol) (PEG) and two cell‐adhesive peptide sequences (CREDVW and CAGW) with the purpose of enhancing antithrombogenic activity and endothelialization. The successful grafting of PEG and peptide sequences is confirmed by X‐ray photoelectron spectroscopy. The suitable surface wettability of the modified vascular graft is testified by water contact angle analysis. The surface hemocompatibility is verified by platelet adhesion assays and protein adsorption assays, and the results demonstrate that both platelet adhesion and protein adsorption on the biofunctionalized surface are significantly reduced. In vitro studies demonstrate that the biofunctionalized surface with suitable hydrophilicity and cell‐adhesive peptides can selectively promote the adhesion, spreading, and proliferation of human umbilical vein endothelial cells. More importantly, compared with control groups, this biofunctionalized small‐caliber vascular graft shows high long‐term patency and endothelialization after 10 weeks of implantation. The biofunctionalization with PEG and two cell‐adhesive peptide sequences is an effective method to improve the endothelialization and long‐term performance of synthetic vascular grafts.  相似文献   

4.
The nonspecific interaction of proteins with surfaces in contact with biofluids leads to adverse problems and is prevented by a biocompatible surface coating. The current benchmark material among such coatings is poly(ethylene glycol) (PEG). Herein, we report on the synthesis of linear polyglycerol derivatives as promising alternatives to PEG. Therefore, gold surfaces as a model system are functionalized with a self‐assembled monolayer (SAM) by a two‐step anhydride coupling and a direct thiol immobilization of linear poly(methyl glycerol) and polyglycerol. Surface plasmon resonance (SPR) spectroscopy reveals both types of functionalized surfaces to be as resistant as PEG towards the adsorption of the test proteins fibrinogen, pepsin, albumin, and lysozyme. Moreover, linear polyglycerols adsorb even less proteins from human plasma than a PEG‐modified surface. Additional cell adhesion experiments on linear poly(methyl glycerol) and polyglycerol‐modified surfaces show comparable cell resistance as for a PEG‐modified surface. Also, in the case of long‐term stability, high cell resistance is observed for all samples in medium. Additional in vitro cell‐toxicity tests add to the argument that linear poly(methyl glycerol) and polyglycerol are strong candidates for promising alternatives to PEG, which can easily be modified for biocompatible functionalization of other surfaces.  相似文献   

5.
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.  相似文献   

6.
This study presents a simple method for the fabrication of an orthogonal surface that can be applied for cell patterning without the need to immobilize specific adhesive peptides, proteins, or extracellular matrix (ECM) for cell attachment. Micromolding in capillaries (MIMIC) produced two distinctive regions. One region contained poly(ethylene glycol)–poly(d,l-lactide) diblock copolymer (PEG–PLA) designed to provide a biological barrier to the nonspecific binding of proteins and fibroblast cells. The other region was coated with polyelectrolyte (PEL) to promote the adhesion of biomolecules including proteins and cells. Resistance to the adsorption of proteins increased with the length of PEG and PLA chains because the longer PEG chain increased the PEG layer thickness and the longer PLA chain induced stronger interaction with the PEL surface. The PEG5k–PLA2.5k (20 mg/ml) was the most efficient candidate for the prevention of protein adhesion among the PEG–PLA copolymers examined. The orthogonal functionality of prepared surfaces having PEL regions and background PEG–PLA regions resulted in rapid patterning of biomolecules. Fluorescein isothiocyanate-tagged bovine serum albumin (FITC-BSA) and fibroblast cells successfully adhered to the exposed PEL surfaces. Although methods for cell patterning generally require an adhesive protein layer on the desired area, these fabricated surfaces without adhesive proteins provide a gentle microenvironment for cells. In addition, our proposed approach could easily control patterns, sizes, and shapes at micron scale.  相似文献   

7.
利用聚多巴胺技术对PTFE进行表面改性,X射线光电子能谱(XPS)、椭偏、接触角以及石英晶体微天平(QCM-D)证实DOPA分子可以在PTFE表面自聚形成反应性的超薄膜功能涂层,并通过聚多巴胺辅助自组装单分子层(SAM)技术构建了活性多肽链段CGREDVDY的界面.细胞黏附实验反映活性链段CGREDVDY的修饰表面具备良好的内皮细胞选择性黏附能力.这种具有内皮细胞选择性黏附能力的界面有望实现材料在复杂生理环境中对内皮细胞的原位诱导,为制备具有血管内皮原位快速愈合功能的新型血液相容性人造血管提供新途径.  相似文献   

8.
The creation of nonfouling surfaces is one of the major prerequisites for microdevices for biomedical and analytical applications. Poly(ethylene glycol) (PEG), a water soluble, nontoxic, and nonimmunogenic polymer has the unique ability of reducing nonspecific protein adsorption and cell adhesion and, therefore, is generally coupled with a wide variety of surfaces to improve their biocompatibility. The performance of these modified surfaces for long-term biomedical applications largely depends on the stability of these PEG films. To this end, we have investigated the stability of covalently coupled ultrathin PEG films on silicon in aqueous in vivo like conditions for a period of 4 weeks. The PEG-modified silicon substrates were incubated in PBS (37 degrees C, pH 7.4, 5% CO2) for different periods of time and then characterized using the techniques of ellipsometry, contact angle measurement, X-ray photoelectron spectroscopy, and atomic force microscopy. The ability of the PEG-modified surfaces to control protein fouling was examined by protein adsorption studies using fluorescein isothiocyanate labeled bovine serum albumin and ellipsometry. Furthermore, the ability of these films to control fibroblast adhesion was examined. Studies suggest that the PEG-modified surfaces retain their protein and cell repulsive nature even though the PEG film thickness decreases for the period of investigation.  相似文献   

9.
海洋贻贝类生物的足丝分泌蛋白几乎能够在所有基底材料上实现高强度、高韧性的粘附,且不受水或者潮湿环境影响。这种环境友好、条件温和的高效生物粘附剂引起了研究人员的兴趣,尤其在粘附机理和应用前景方面更是研究人员关注的重点。大量研究表明,贻贝超强的粘附能力与其分泌的粘附蛋白中高含量的3,4-二羟基苯丙氨酸(多巴,DOPA)单元相关。受贻贝粘附蛋白的启发,人们研究发现,多巴胺(DA)分子具有与之相似的官能团,聚合后有相似分子结构,使用聚多巴胺替代聚多巴,可以在基体表面达到相似的粘附性能。本文简单介绍了仿贻贝粘性物质中的代表多巴胺自聚合形成聚多巴胺(PDA)与粘附机理,并重点介绍了近年来DOPA衍生物在表面改性、催化、生物防污及生物医学领域的应用和前景。  相似文献   

10.
An approach to control cell adhesion using a photocleavable molecule on chitosan has been developed and studied. Photocleavable 4,5-dimethoxy-2-nitrobenzyl chloroformate (NVOC) was introduced into chitosan to control the surface properties. The two UV illuminations with a photomask controlled the cleavage of NVOC and the presentation of deprotected amines on one chitosan surface spatially and temporally. The following immobilizations of cell repulsive poly(ethylene glycol) after the first illumination and cell adhesive sequence Arg-Gly-Asp-Ser (RGDS) after the second illumination on the surface helped create surface heterogeneity. Fourier transform infrared spectroscopy (FTIR), water contact angle, and UV-visible spectroscopy were used to characterize the surfaces and photoactivation during the process. To study the cell attachment and morphology on our designed surfaces, NIH/3T3 fibroblast cell was used. Cell number and morphology on the surfaces were investigated. The cell study demonstrated the feasibility of the surfaces on the control of cell adhesion and the formation of cell patterns by UV illuminations and the following immobilizations of different biomolecules.  相似文献   

11.
Covalent attachment of adhesive peptides to biomaterials surfaces can result in the formation of a bioactive and biomimetic surface. We have demonstrated that titanium surfaces grafted with adhesion peptides, reproducing sequences of fibronectin and vitronectin, can increase osteoblast adhesion compared to non-treated surfaces.We now extend our investigation to peptide immobilization on glass for studying human osteoblast adhesion and spreading. Silanization was used to anchor adhesion peptides to the glass surface through a selective or a non-selective immobilization. Investigated samples were analysed by XPS spectroscopy. Comparison between the results obtained using two different peptides and applying selective and non-selective immobilization will be discussed.  相似文献   

12.
Cellular patterning on silicon platforms is the basis for development of integrated cell-based biosensing devices, for which long-term cell selectivity and biostability remain a major challenge. We report the development of a silicon-based platform in a metal-insulator format capable of producing uniform and biostable cell patterns with long-term cell selectivity. Substrates patterned with arrays of gold electrodes were surface-engineered such that the electrodes were activated with fibronectin to mediate cell attachment and the silicon oxide background was passivated with PEG to resist protein adsorption and cell adhesion. Three types of oxide surfaces, i.e., native oxide, dry thermally grown oxide, and wet thermally grown oxide, were produced to illustrate the effect of oxide state of the surface on long-term cell selectivity. Results indicated that the cell selectivity over time differed dramatically among three patterned platforms and the best cell selectivity was found on the dry oxide surface for up to 10 days. Surface analysis results suggested that this enhancement in cell selectivity may be related to the presence of additional, more active oxide states on the dry oxide surface supporting the stability of PEG films and effectively suppressing the cell adhesion. This research offers a new strategy for development of stable and uniform cell-patterned surfaces, which is versatile for immobilization of silane-based chemicals for preparation of biostable interfaces.  相似文献   

13.
A variety of biomedical applications requires tailored membranes; fabrication through a mix‐and‐match approach is simple and desired. Polymers based on supramolecular bis‐urea (BU) moieties are capable of modular integration through directed non‐covalent stacking. Here, it is proposed that non‐cell adhesive properties can be introduced in polycaprolactone‐BU‐based membranes by the addition of poly(ethylene glycol) (PEG)‐BU during immersion precipitation membrane fabrication, while unmodified PEG is not retained in the membrane. PEG‐BU addition results in denser membranes with a similar pore size compared to pristine membranes, while PEG addition induces defect formation. Infrared spectroscopy and surface hydrophobicity measurements indicate that PEG‐BU is retained during membrane processing. Additionally, PEG‐BU incorporation successfully leads to poor cell adhesive surfaces. No evidence is observed to indicate PEG retention. The results obtained indicate that the BU system enables intimate mixing of BU‐modified polymers after processing. Collectively, the results provide the first steps toward BU‐based immersion precipitated supramolecular membranes for biomedical applications.  相似文献   

14.
In this paper, we demonstrate the first use of a catecholic initiator for surface-initiated polymerization (SIP) from metal surfaces to create antifouling polymer coatings. A new bifunctional initiator inspired by mussel adhesive proteins was synthesized, which strongly adsorbs to Ti and 316L stainless steel (SS) substrates, providing an anchor for surface immobilization of grafted polymers. Surface-initiated atom transfer radical polymerization (SI-ATRP) was performed through the adsorbed biomimetic initiator to polymerize methyl methacrylate macromonomers with oligo(ethylene glycol) (OEG) side chains. X-ray photoelectron spectroscopy, surface FT-IR, and contact angle analysis confirmed the sequential grafting of initiator and polymer, and ellipsometry indicated the formation of polymer coatings of up to 100 nm thickness. Cell adhesion experiments performed with 3T3-Swiss albino fibroblasts showed substantially reduced cell adhesion onto polymer grafted Ti and 316L SS substrates as compared to the unmodified metals. Moreover, micropatterning of grafted polymer coatings on Ti surfaces was demonstrated by combining SI-ATRP and molecular assembly patterning by lift-off (MAPL), creating cell-adhesive and cell-resistant regions for potential use as cell arrays. Due to the ability of catechols to bind to a large variety of inorganic surfaces, this biomimetic anchoring strategy is expected to be a highly versatile tool for polymer thin film surface modification for biomedical and other applications.  相似文献   

15.
A novel bioinspired strategy for protein nanoparticle (NP) synthesis to achieve pH‐responsive drug release exploits the pH‐dependent changes in the coordination stoichiometry of iron(III)–3,4‐dihydroxyphenylalanine (DOPA) complexes, which play a major cross‐linking role in mussel byssal threads. Doxorubicin‐loaded polymeric NPs that are based on FeIII–DOPA complexation were thus synthesized with a DOPA‐modified recombinant mussel adhesive protein through a co‐electrospraying process. The release of doxorubicin was found to be predominantly governed by a change in the structure of the FeIII–DOPA complexes induced by an acidic pH value. It was also demonstrated that the fabricated NPs exhibited effective cytotoxicity towards cancer cells through efficient cellular uptake and cytosolic release. Therefore, it is anticipated that FeIII–DOPA complexation can be successfully utilized as a new design principle for pH‐responsive NPs for diverse controlled drug‐delivery applications.  相似文献   

16.
Biomacromolecules like gelatin and chitosan have emerged as highly versatile biomimetic coatings for applications in tissue engineering. The elucidation of the interfacial kinetics of cell adhesion on biomacromolecular surfaces will pave the way for the rational design of chitosan/gelatin-based systems for cell regeneration. Biomacromolecular ultra-thin films, chemically immobilized on fused silica are ideal experimental models for determining the effect of surface properties on the biophysical cascades following cell seeding. In this study, confocal reflectance interference contrast microscopy (C-RICM), in conjunction with phase contrast microscopy and fluorescence confocal microscopy, was applied to detect the adhesion contact dynamics of 3T3 fibroblasts on chitosan and gelatin ultrathin films. X-ray photoelectron spectroscopy (XPS) confirmed the immobilization of chitosan or gelatin on the silanized glass surface. Both the initial cell deformation rate and the change of two-dimensional spread area of the 3T3 fibroblasts are higher on gelatin-modified surfaces than on chitosan surfaces. The steady-state adhesion energy of 3T3 fibroblasts on gelatin film is three times higher than that on chitosan film. Immuno-staining of actin further demonstrates the different organization of cytoskeleton, likely induced by the change in cell signaling mechanism on the two biomacromolecular surfaces. The better attachment of 3T3 fibroblast to gelatin is postulated to be caused by the presence of adhesive domains on gelatin.  相似文献   

17.
New peptidomimetic polymers for antifouling surfaces   总被引:2,自引:0,他引:2  
Exposure of therapeutic and diagnostic medical devices to biological fluids is often accompanied by interfacial adsorption of proteins, cells, and microorganisms. Biofouling of surfaces can lead to compromised device performance or increased cost and in some cases may be life-threatening to the patient. Although numerous antifouling polymer coatings have enjoyed short-term success in preventing protein and cell adsorption on surfaces, none have proven ideal for conferring long-term biofouling resistance. Here we describe a new biomimetic antifouling N-substituted glycine polymer (peptoid) containing a C-terminal peptide anchor derived from residues found in mussel adhesive proteins for robust attachment of the polymer onto surfaces. The methoxyethyl side chain of the peptoid portion of the polymer was chosen for its chemical resemblance to the repeat unit of the known antifouling polymer poly(ethylene glycol) (PEG), whereas the composition of the 5-mer anchoring peptide was chosen to directly mimic the DOPA- and Lys-rich sequence of a known mussel adhesive protein. Surfaces modified with this biomimetic peptide-peptoid conjugate exhibited dramatic reduction of serum protein adsorption and resistance to mammalian cell attachment for over 5 months in an in vitro assay. These new synthetic peptide based antifouling polymers may provide long-term control of surface biofouling in the physiologic, marine, and industrial environments.  相似文献   

18.
The uncontrolled accumulation of biological materials on the surface of medical devices through protein adsorption or cell adhesion causes adverse biological reactions in the living host system, leading to complications. In this study, poly(ethylene glycol) (PEG) is successfully grafted onto polyurethane (PU) surfaces by using a new strategy through a simple and efficient transurethanization reaction. The PEG hydroxyl group is deprotonated and then reacted with the PU surface to provide antiadhesive hydrophilic surfaces in a single step. Surface analysis techniques proved the grafting to be efficient and the formation of a hydrophilic polymeric layer at the surface of PU. Biological assays showed that the surface modification induced lower protein adsorption, cell, platelet, and bacterial adhesion than untreated surfaces, showing a potential for biomedical applications.  相似文献   

19.
Specific and reversible adhesion of a terminal thymine-functionalized polystyrene (PS-thymine) was demonstrated for a silicon surface with complementary adenine recognition sites. A novel adenine-containing triethoxysilane (ADPTES), which was suitable for covalent attachment to silanol containing surfaces, was synthesized in one step from adenine and 3-isocyanatopropyl triethoxysilane (IPTES). 1H and 13C NMR spectroscopy and fast atom bombardment mass spectroscopy confirmed the chemical structure, and 29Si NMR spectroscopy indicated the absence of any premature hydrolysis of the alkoxysilane derivative. X-ray photoelectron spectroscopy (XPS) and water contact angle measurements indicated the attachment of PS-thymine to silicon surfaces that were modified with a mixture of ADPTES and 3-mercaptopropyl triethoxysilane (MPTES). PS-thymine attachment to surfaces that were modified with only MPTES was not observed. The exclusive attachment of PS-thymine to an ADPTES/MPTES-modified surface confirmed hydrogen bonding-mediated adenine-thymine association to silicon surfaces containing a sufficiently low concentration of adenine recognition sites. Although PS-thymine attachment to the ADPTES/MPTES-modified surfaces was insensitive to THF rinsing, the PS-thymine was completely removed from the surface upon DMSO rinsing because of the disruption of adenine-thymine hydrogen bonding with a more polar aprotic solvent. PS-thymine was successfully reattached to the ADPTES/MPTES-modified surface following the DMSO rinse, demonstrating the solvato-reversible nature of the adenine-thymine association.  相似文献   

20.
为了更好地理解贻贝在表面的黏附机理,实现水下胶黏,采用分子动力学方法研究了多巴在自组装膜上的黏附性:采用伞形取样和加权柱状图分析方法计算了多巴在不同自组装膜表面的黏附自由能,使用拉伸分子动力学模拟研究了多巴在不同自组装膜表面上黏附后的脱附力.结果表明,多巴在带负电的羧基自组装膜上的黏附能比在带正电的氨基自组装膜上的大,多巴更容易黏附到带负电表面;多巴在带电表面的黏附能比未带电表面的黏附能更强,表明在带电表面黏附更稳定.进一步分析了多巴在不同表面的取向分布,发现多巴与不同表面相互作用的方式不同:与疏水表面主要通过苯环相互作用;与亲水表面主要通过羟基相互作用;与负电表面主要通过氨基相互作用;与正电表面主要通过羧基相互作用.通过模拟比较了多巴在不同自组装膜上的脱附力,发现多巴在带电表面的脱附力比在未带电表面的大,与黏附能的趋势一致.对比4种非带电表面的脱附力,发现多巴在疏水性甲基自组装膜表面的脱附力最大,黏附更稳定,随着表面疏水性的增加,脱附力增大,黏附稳定性增强.本工作可为研发新型水下胶黏剂提供理论指导.  相似文献   

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