Polystyrene derivatives with lactose, glucose, maltose, maltotriose, maltopentaose, and maltoheptaose on each benzene ring were prepared by the radical polymerization of a new class of macromers synthesized by coupling the corresponding oligosaccharide lactones with p-vinylbenzylamine. These polymers consisting of amphiphilic structural units were water-soluble, and organic solutes were bound to hydrophobic microenvironments of the polymers in water. α-D-Glucopyranose-carrying polymers were recognized and precipitated by concanavalin A. Cultivation of liver cells (hepatocytes) was attempted using culture dishes whose surface was coated with lactose-, glucose-, maltose-, and maltotriose-carrying polystyrenes. It has been found that a lactose-carrying polystyrene (PVLA) is a useful surface material for hepatocyte culture. 1) Highly specific adhesion of hepatocytes was attained for PVLA-coated dishes with or without serum supplement. 2) The cell adhesion was a threshold phenomenon with respect to the PVLA concentration on the dish. 3) The cell adhesion was effectively inhibited when hepatocytes were treated with PVLA molecules in the medium prior to culture. 4) The adhesion was not inhibited by albumin, an adhesion-inhibitory protein in serum. These findings suggest that pendent galactose residues of a PLVA molecule functioned as a strong recognition determinant for hepatocytes. We assume that multi-antennary, high-density galactose residues of PVLA are attributed to the specific adhesion of hepatocytes. 相似文献
Mesoporous silica nanoparticles (MSNs) are one of the most promising nanocarriers in biomedicine. Nonetheless, surface modification has been pointed out as a condition necessary for drug delivery applications, where stability and biocompatibility are extremely important for the vehicle performance. Likewise, zwitterionic polymers are outstanding candidates in biological fields, where poly(sulfobetaine methacrylate) (pSBMA) has been widely studied. These polymers, known as antifouling materials, are able to render a surface capacity to avoid protein adhesion. In this work, a core‐shell nanocarrier was created, where pSBMA was covalently grafted by atom transfer radical polymerization (ATRP) onto a previously functionalized MSN surface. Brush morphologies with different chain lengths ( , between 6500 and 32 300) and graft densities (σpSBMA, between 0.15 and 0.51 molecules of pSBMA per nm2 of MSN) were obtained. Protein adhesion resistance was evaluated with two proteins: fibronectin (FN) and bovine serum albumin (BSA). The best nanocarrier synthesized allowed a reduction of 96% of FN and 76% of BSA adhesion (compared with an adsorption of 100% assigned to the native material). Since the influence of the brush morphology is seldom studied or reported, this work aims to comprehend how the configuration of the polymer brushes affected their antifouling capacity, in order to use this pSBMA‐MSN product for biomedical applications, notably as a possible drug delivery nanocarrier. Future work will analyze the solution behavior of the zwitterionic brushes to evaluate variations of temperature and pH values as possible mechanisms of delivery. 相似文献
An atomic force microscope (AFM) in conjunction with coated colloid probe and cell probe techniques has been used to measure directly the adhesive force between both the protein bovine serum albumin (BSA) and a yeast cell at two different membranes. These were polymeric ultrafiltration membranes of similar MWCO (4000 Da) but of different materials (ES 404 and XP 117, PCI Membrane Systems, UK). The XP 117 membrane is made from a mixture of polymers chosen with the aim of achieving low fouling. The BSA was adsorbed on a 5 μm silica colloid probe formed from a tipless V-shaped AFM cantilever. The cell probe was created by immobilising a single yeast cell on such a tipless cantilever. Measurements were made in 10−2 M NaCl solution. It was found for both protein and cell systems that the adhesive force at the ES 404 membrane was greater than that at the XP 117 membrane. The paper shows that coated colloid probe and cell probe techniques can provide useful means of directly quantifying the adhesion of biological materials to membrane surfaces. 相似文献
A simple yet versatile method was developed to prepare a low-density polymerization initiator gradient, which was combined with surface-initiated atom transfer radical polymerization (ATRP) to produce a well-defined poly(2-hydroxyethyl methacrylate) (HEMA) gradient substrate. A smooth variation in film thickness was measured across the gradient, ranging from 20 A to over 80 A, but we observed a nonmonotonic variation in water contact angle. Fits of X-ray reflectivity profiles suggested that at the low graft density end, the polymer chain structure was in a "mushroom" regime, while the polymer chains at high graft density were in a "brush" regime. It was found that the "mushroom" region of the gradient could be made adhesive to cells by adsorbing adhesion proteins, and cell adhesion could be tuned by controlling the density of the polymer grafts. Fibroblasts were seeded on gradients precoated with fibronectin to test cellular responses to this novel substrate, but it was found that cell adhesion did not follow the expected trend; instead, saturated cell adhesion and spreading was found at the low grafting density region. 相似文献
When normal or SV40-transformed Balb/c 3T3 cells are treated with the Ca++-specific chelator EGTA, they round up and pull away from their footpad adhesion sites to the serum-coated tissue culture substrate, as shown by scanning electron microscope studies. Elastic membranous retraction fibers break upon culture agitation, leaving adhesion sites as substrate-attached material (SAM) (Cells leave "footprints" of substrate adhesion sites during movement by a very similar process.) SAM contains 1-2% of the cell's total protein and phospholipid content and 5-10% of its glucosamine-radiolabeled polysaccharide, most of which is glycosaminoglycan (GAG). By one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, there is considerable enrichment in SAM for specific GAGs; for the glycoprotein fibronectin; and for the cytoskeletal proteins actin, myosin, and the subunit protein of the 10 nm-diameter filaments. Fibrillar fibronectin of cellular origin and substratum-bound fibronectin of serum origin (cold-insoluble globulin, CIg) have been visualized by immunofluorescence microscopy. The GAG composition in SAM has been examined under different cellular growth and attachment conditions. Heparan sulfate content correlates with glycopeptide content (derived from glycoprotein). Newly attaching cells deposit SAM with principally heparan sulfate and fibronectin and little of the other GAGs. Hyaluronate and chrondroitin proteoglycans are coordinately deposited in SAM as cells begin spreading and movement over the substrate. Cells attaching to serum-coated or CIg-coated substrates deposited SAM with identical compositions. The proteoglycan nature of the GAGs in SAM has been examined, as well as the ability of proteoglycans to form two classes of reversibly dissociable "supramolecular complexes" - one class with heparan sulfate and glycopeptide-containing material and the second with hyaluronate-chondroitin complexes. Enzymatic digestion of "intact" SAM with trypsin or testicular hyaluronidase indicates that (1) only a small portion of long-term radiolabeled fibronectin and cyto-skeletal protein is bound to the substrate via hyaluronate or chondroitin classes of GAG; (2) most of the fibronectin, cytoskeletal protein and heparan sulfate coordinately resist solubilization; and (3) newly synthesized fibronectin, which is metabolically labile in SAM, is linked to SAM by hyaluronate- and/or chondroitin-dependent binding. All of our studies indicate that heparan sulfate is a direct mediator of adhesion of cells to the substrate, possibly by binding to both cell-surface fibronectin and substrate-bound CIg in the serum coating; hyaluronate-chondroitin complexes in SAM appear to be most important in motility of cells by binding and labilizing fibronectin at the periphery of footpad adhesions, with subsequent cytoskeletal disorganization. 相似文献
It was shown that molded specimens of polymer composite materials can be obtained by an extrusion method by melt blending of Fluoroplast F-2 MB (modified poly(vinylidene difluoride)) and oxyfluoride glasses of the composition 3B2O3 (40SnF2–30SnO–30P2O5). The compositions of the observed phases of the composites were determined. Conclusions were made on the incompatibility of the components, their dispersion distribution, and strong adhesion interaction. Data on the nano level of the blending of the components were obtained. The elongation and Brinell hardness were measured in the composites with various (0–50 vol %) oxyfluoride contents. It was concluded that it is possible to produce composites based on fluorinated hydrocarbon and fluoroxide polymers. 相似文献
Abstract Chemical modification of biosignal proteins for design and synthesis of biocompatible polymers is described. Biosignal proteins were immobilized onto polymer film to obtain hybrid film for regulating cellular functions. Immobilization of adhesion or growth protein enhanced cell adhesion or growth, respectively. Coimmobilization of these proteins markedly enhanced the growth of anchorage-dependent cells. This concept of materials design was applied for endothelialization of artificial blood vessel. 相似文献
In this work, 3-methylthiophene (MeT) was electrochemically incorporated with nano- and mesoporous TiO2 films to form poly(3-methylthiophene) (PMeT)/TiO2 nanocomposite electrochromic electrodes. TiO2 films, which were previously coated on the ITO glass sheets through a well-established technique, were introduced to enhance
the adhesion of the polymers to the substrates and thus increase the long-term stability of the devices. With this effort,
the nanocomposite electrodes were found to retain up to 60% of their optical response after 3,500 deep and double potential
steps and retain up to 50% of their electroactivity after 104 same steps, exhibiting enhanced long-term stability. Switching time and the maximum optical contrast (ΔT%) of the nanocomposite electrodes were found to be 0.6 s and 45%, respectively. Moreover, our work showed that electrochemically
incorporating conductive polymers (CPs) with TiO2 mesoporous films was an effective method to form high-quality CP/TiO2 nanocomposite electrodes, which can be used widely in battery cathodes, photovoltaic cells, photocatalytic reaction, and
photoelectrochromic cells and were supposed to enhance their performances. 相似文献
Several species in nature have special wetting properties such as Lotus leaves or rose petals. Both the surface morphology and surface energy play a fundamental role. In particular, nanofibers were found to be exceptional surface structures due to a possible control in both water hydrophobicity and water adhesion as a function of their length, diameter, their orientation to the substrate or the spacing between them. Here, in the aim to prepare nanofibers with high liquid-repellent properties using conducting polymers, we have synthesized 3,4-propylenedioxypyrrole (ProDOP) derivatives with hydrocarbon and fluorocarbon chains in the 3-position, keeping the NH group free (important condition to lead to nanofibers thanks to hydrogen bonds). Different hydrocarbon and fluorocarbon chain lengths are studied. We obtain, for example, nanofibers of different size with octyl, decyl and C4F9 chains (intermediate hydrophobicity) with different liquid-repellent properties and liquid adhesion properties. More precisely, PProDOP-H8 is close to superhydrophobic properties (low water adhesion) while PProDOP-H10 is parahydrophobic (high water adhesion). This works could find many potential applications in the nanotechnology field as water harvesting surfaces, liquid separation membrane, and in anti-bioadhesion. Due to the presence of free NH groups, these materials could also be used as pH-sensitive materials while the nitrogen could also be easily functionalized. 相似文献
It is well-known that protein-modified implant surfaces such as TiO(2) show a higher bioconductivity. Fibronectin is a glycoprotein from the extracellular matrix (ECM) with a major role in cell adhesion. It can be applied on titanium oxide surfaces to accelerate implant integration. Not only the surface concentration but also the presentation of the protein plays an important role for the cellular response. We were able to show that TiO(X) surfaces modified with biotinylated fibronectin adsorbed on a streptavidin-silane self-assembly multilayer system are more effective regarding osteoblast adhesion than surfaces modified with nonspecifically bound fibronectin. The adsorption and conformation behavior of biotinylated and nonbiotinylated (native) fibronectin was studied by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM). Imaging of the protein modification revealed that fibronectin adopts different conformations on nonmodified compared to streptavidin-modified TiO(X) surfaces. This conformational change of biotinylated fibronectin on the streptavidin monolayer delivers a fibronectin structure similar to the conformation inside the ECM and therefore explains the higher cell affinity for these surfaces. 相似文献
Vapor‐deposited silicone coatings are attractive candidates for providing insulation in neuroprosthetic devices owing to their excellent resistivity, adhesion, chemical inertness and flexibility. A biocompatibility assessment of these coatings is an essential part of the materials design process, but current techniques are limited to rudimentary cell viability assays or animal muscle implantation tests. This article describes how a recently developed in vitro model of glial scar formation can be utilized to assess the biocompatibility of vapor‐deposited silicone coatings on micron‐scale wires. A multi‐cellular monolayer comprising mixed glial cells was obtained by culturing primary rat midbrain cells on poly(D ‐lysine)‐coated well plates. Stainless steel microwires were coated with two novel insulating thin film silicone polymers, namely poly(trivinyltrimethylcyclotrisiloxane) (polyV3D3) and poly(trivinyltrimethylcyclotrisiloxane–hexavinyldisiloxane) (polyV3D3–HVDS) by initiated chemical vapor deposition (iCVD). The monolayer of midbrain cells was disrupted by placing segments of coated microwires into the culture followed by immunocytochemical analysis after 7 d of implantation. Microglial proximity to the microwires was observed to correlate with the amount of fibronectin adsorbed on the coating surface; polyV3D3–HVDS adsorbed the least amount of fibronectin compared to both stainless steel and polyV3D3. Consequently, the relative number of microglia within 100 µm of the microwires was least on polyV3D3–HVDS coatings compared to steel and polyV3D3. In addition, the astrocyte reactivity on polyV3D3–HVDS coatings was lower compared to stainless steel and polyV3D3. The polyV3D3–HVDS coating was therefore deemed to be most biocompatible, least reactive and most preferable insulating coating for neural prosthetic devices.
Mussel‐inspired poly(dopamine) (PDA) coating is proven to be a simple, versatile, and effective strategy to promote cell adhesion onto various substrates. In this study, the initial adhesive behavior of human umbilical vein endothelial cells (HUVECs) is evaluated on a PDA coating under serum‐free conditions. It is found that HUVECs can attach directly to and spread with well‐organized cytoskeleton and fibrillar adhesions on the PDA surface, whereas cells adhere poorly to and barely spread on the control polycaprolactone surface. Endogenous fibronectin and α5β1 integrin are found to be involved in the cell adhesion process. These findings will lead to a better understanding of interactions between cells and PDA coating, paving the way for the further development of PDA.
The influence of dielectric substrates on the Raman scattering activities of Ag overlayers has been investigated. Materials
with low refractive indices, such as SiO2, SiOx and AlF3, were found to provide suitable supporting platforms for Ag films to give strong surface-enhanced Raman scattering for dye
molecules when illuminated at 488 nm. This finding was then extended to tip-enhanced Raman scattering (TERS). Huge enhancements
of 70–80×, corresponding to net enhancements of >104, were observed for brilliant cresyl blue test analyte when Ag-coated tips made from or precoated with low refractive index
materials were applied. The yield of fabricated tips that significantly enhance the Raman signals was found to be close to
100%. These findings provide crucial steps towards the use of TERS as a robust technique for rapid chemical imaging with nanometer
spatial resolution.
Figure Silver-coated dielectric tips for tip-enhanced Raman scattering (TERS) are capable of more than 10,000-fold enhancement 相似文献
In the basic approach to investigations of neuronal--glial interactions during both normal brain development and its pathogenesis, embryonic brain cell populations were fractionated into purified neuronal and glial components. Using separation procedures based on differential adhesion and cytotoxicity, the isolated neuronal and glial phenotypes could be identified by distinct morphological and biochemical characteristics, including the visualization of glial fibrillary acid protein (GFA) within glial cells in immunohistochemical assays with monospecific anti-GFA serum. When unfractionated cerebrum cells dissociated from 10-day chick or 14-day mouse embryos were plated as monolayers and cultured for 1--14 days, monospecific antiserum against fibronectin (LETS glycoprotein) was found to react with many, but not all, of the cells as revealed by indirect immunofluorescence microscopy. The isolated neuronal and glial components of these populations were used to determine whether the appearance of membrane-associated fibronectin was characteristic of one cell type or the other, or both, and if neuronal--glial cell interaction was required for its expression. It was found that the surfaces of glial cells, completely isolated from neurons, showed an intense fluorescent reaction to the anti-fibronectin serum. In contrast, the purified neuronal cultures showed no fluorescence with either the anti-GFA or anti-fibronectin sera. These results demonstrate fibronectin as a cell surface protein associated primarily with glial cells and independent of neuronal--glial cell interaction for its expression. Furthermore, the results indicate that the fibronectin observed on glial cell surfaces in these cultures is produced endogenously and is not due to the preferential binding of fibronectin present in the culture medium. The role of fibronectin as an adhesive molecule in neuronal--glial interactions is discussed. 相似文献
The soft tissue sealing at the transmucal portion of implants is vital for the long-term stability of implants. Hydrogenated titanium nanotubes (H2-TNTs) as implant surface treatments were proved to promote the adhesion of human gingival fibroblasts (HGFs) and have broad usage as drug delivery systems. Bovine serum albumin (BSA) as the most abundant albumin in body fluid was crucial for cell adhesion and was demonstrated as a normal loading protein. As the first protein arriving on the surface of the implant, albumin plays an important role in initial adhesion of soft tissue cells, it is also a common carrier, transferring and loading different endogenous and exogenous substances, ions, drugs, and other small molecules. The aim of the present work was to investigate whether BSA-loaded H2-TNTs could promote the early adhesion of HGFs; H2-TNTs were obtained by hydrogenated anodized titanium dioxide nanotubes (TNTs) in thermal treatment, and BSA was loaded in the nanotubes by vacuum drying; our results showed that the superhydrophilicity of H2-TNTs is conducive to the loading of BSA. In both hydrogenated titanium nanotubes and non-hydrogenated titanium nanotubes, a high rate of release was observed over the first hour, followed by a period of slow and sustained release; however, BSA-loading inhibits the early adhesion of human gingival fibroblasts, and H2-TNTs has the best promoting effect on cell adhesion. With the release of BSA after 4 h, the inhibitory effect of BSA on cell adhesion was weakened. 相似文献
Polyelectrolyte multilayers assembled from hyaluronic acid (HA) and poly‐l ‐lysine (PLL) are most widely studied showing excellent reservoir characteristics to host molecules of diverse nature; however, thick (HA/PLL)n films are often found cell repellent. By a systematic study of the adhesion and proliferation of various cells as a function of bilayer number “n” a correlation with the mechanical and chemical properties of films is developed. The following cell lines have been studied: mouse 3T3 and L929 fibroblasts, human foreskin primary fibroblasts VH‐Fib, human embryonic kidney HEK‐293, human bone cell line U‐2‐OS, Chinese hamster ovary CHO‐K and mouse embryonic stem cells. All cells adhere and spread well in a narrow “cell‐friendly” window identify in the range of n = 12–15. At n < 12, the film is inhomogeneous and at n > 15, the film is cell repellent for all cell lines. Cellular adhesion correlates with the mechanical properties of the films showing that softer films at higher “n” number exhibiting a significant decrease of the Young's modulus below 100 kPa are weakly adherent to cells. This trend cannot be reversed even by coating a strong cell‐adhesive protein fibronectin onto the film. This indicates that mechanical cues plays a major role for cell behavior, also in respect to biochemical ones. 相似文献
The organic–inorganic composite materials based on mesoporous silica were synthesized using sol–gel method. The surface area of silicas was modified by bovine serum albumin (BSA) and guanidine polymers: polyacrylate guanidine (PAG) and polymethacrylate guanidine. The mesoporous silicas were characterized by nitrogen adsorption–desorption analysis, Fourier transform infrared spectroscopy, transmission electron microscopy. The obtained materials were used as adsorbents for selective bilirubin removal. It was shown that the structural properties and surface area of modified materials depend on the nature of polymers. Incorporation of polymers in silica gel matrix during sol–gel process leads to the formation of mesoporous structure with high pore diameter and a BET surface area equals to 346 m2/g for SiO2/BSA and 160 m2/g for SiO2/PAG. Analysis of adsorption isotherms showed that modification of silica by BSA and guanidine polymers increases its adsorption ability to bilirubin molecules. According to Langmuir model, the maximum bilirubin adsorption capacity was 1.18 mg/g. 相似文献