scholarly journals Dextran Grafted Silicon Substrates: Preparation, Characterization And Biomedical Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Michela Ombelli ◽  
David M. Eckmann ◽  
Russell J. Composto
Keyword(s):  
Protein Interactions ◽  
Chemical Characterization ◽  
Biological Properties ◽  
Silicon Substrates ◽  
Molecular Weight Range ◽  
Angle Measurements ◽  
Surface Analysis Techniques ◽  
Embolism And Thrombosis ◽  
Contact Angle Measurements ◽  
Molecular Aspects

AbstractBiodevices used in the cardiovascular system suffer from well-known problems associated with surface-induced gas embolism and thrombosis. In order to improve the biocompatibility of these devices, biomimetic coatings show good promise. We recently synthesized a coating layer of dextran, a relatively simple and well characterized neutral polysaccharide, with the purpose of mimicking the cells' glycocalyx layer, that prevents non-specific cells-protein interactions. Systematic physical chemical characterization was performed on coatings obtained both from commonly used polydisperse dextrans and low-dispersity dextrans in the 1-100 kDalton molecular weight range.We have combined standard surface analysis techniques, such as ellipsometry, contact angle measurements and AFM, with less traditional vibrational spectroscopy techniques in the characterization of our biomimetic coatings. FTIR, micro-FTIR and micro-Raman spectroscopies were utilized to correlate the conformational and molecular aspects of the grafted poly- and monodisperse dextran chains to their attractive biological properties.

Modifications of Paper Surfaces with Composite SiOx/Polymer Coatings

2015 ◽  
Vol 731 ◽  
pp. 437-440
Author(s):  
Zhuang Liu ◽  
Lin Zhu ◽  
Zhi Hui Sun
Keyword(s):  
Contact Angle ◽  
Testing Machine ◽  
Composite Films ◽  
Chemical Characterization ◽  
Polymer Coatings ◽  
Tensile Testing Machine ◽  
Angle Measurements ◽  
Static Contact ◽  
Contact Angle Measurements ◽  
The Individual

The composite SiOx/polymer films are deposited as a top-coatings onto the paper substrates by radio frequency (RF) reactive magnetron co-sputtered two targets, silica and dicyclopentadiene dioxide cured with maleic anhydride (DCPD/MA).The samples prepared by changing PSiO2/PDCPD/MA, the ratio of RF powers density delivered to the individual target from 0.1 to 10 so as to prepare different SiOxcontent coatings. The wettability, mechanical properties, color reproduction printability, chemical characterization of the coatings are discussed in this paper, using contact angle measurements, electronic tensile testing machine, off-set printing test and FTIR. The static contact angle of water ranges from 129.7 to 90.7 o and tensile performance has improved significantly as the ratio of RF powers density change from 0.1 to 10. The ink density and depth of color during off-set printing are visually improved by using papers with hydrophobic surfaces coated composite films.

scholarly journals Functionalization of Hydroxyapatite Ceramics: Raman Mapping Investigation of Silanization

Ceramics ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 372-384 ◽  
Author(s):  
David Siniscalco ◽  
Maggy Dutreilh-Colas ◽  
Zahi Hjezi ◽  
Julie Cornette ◽  
Nadia El Felss ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Biological Properties ◽  
Covalent Immobilization ◽  
Raman Mapping ◽  
Surface Distribution ◽  
Angle Measurements ◽  
Hydroxyapatite Ceramics ◽  
Contact Angle Measurements ◽  
Biomaterial Surfaces

Surface modification of bioceramic materials by covalent immobilization of biomolecules is a promising way to improve their bioactivity. This approach implies the use of organic anchors to introduce functional groups on the inorganic surface on which the biomolecules will be immobilized. In this process, the density and surface distribution of biomolecules, and in turn the final biological properties, are strongly influenced by those of the anchors. We propose a new approach based on Raman 2D mapping to evidence the surface distribution of organosilanes, frequently used as anchors on biomaterial surfaces on hydroxyapatite and silicated hydroxyapatite ceramics. Unmodified and silanized ceramic surfaces were characterized by means of contact angle measurements, atomic force microscopy (AFM) and Raman mapping. Contact angle measurements and AFM topographies confirmed the surface modification. Raman mapping highlighted the influence of both the ceramic’s composition and silane functionality (i.e., the number of hydrolysable groups) on the silane surface distribution. The presence of hillocks was shown, evidencing a polymerization and/or an aggregation of the molecules whatever the silane and the substrates were. The substitution of phosphate groups by silicate groups affects the covering, and the spots are more intense on SiHA than on HA.

scholarly journals Synthesis and Characterization of Electrospun Composite Scaffolds Based on Chitosan-Carboxylated Graphene Oxide with Potential Biomedical Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2535
Author(s):  
Elena Cojocaru ◽  
Jana Ghitman ◽  
Elena Iuliana Biru ◽  
Gratiela Gradisteanu Pircalabioru ◽  
Eugeniu Vasile ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Cellular Proliferation ◽  
Biological Properties ◽  
Synthesis Process ◽  
Composite Scaffolds ◽  
Angle Measurements ◽  
Nanofibrous Scaffolds ◽  
Contact Angle Measurements ◽  
Poly Ethylene

This research study reports the development of chitosan/carboxylated graphene oxide (CS/GO-COOH) composite scaffolds with nanofibrous architecture using the electrospinning method. The concept of designed composite fibrous material is based on bringing together the biological properties of CS, mechanical, electrical, and biological characteristics of GO-COOH with the versatility and efficiency of ultra-modern electrospinning techniques. Three different concentrations of GO-COOH were added into a chitosan (CS)-poly(ethylene oxide) (PEO) solution (the ratio between CS/PEO was 3/7 (w/w)) and were used in the synthesis process of composite scaffolds. The effect of GO-COOH concentration on the spinnability, morphological and mechanical features, wettability, and biological properties of engineered fibrous scaffolds was thoroughly investigated. FTIR results revealed the non-covalent and covalent interactions that could take place between the system’s components. The SEM micrographs highlighted the nanofibrous architecture of scaffolds, and the presence of GO-COOH sheets along the composite CS/GO-COOH nanofibers. The size distribution graphs showed a decreasing trend in the mean diameter of composite nanofibers with the increase in GO-COOH content, from 141.40 nm for CS/PG 0.1% to 119.88 nm for CS/PG 0.5%. The dispersion of GO-COOH led to composite scaffolds with increased elasticity; the Young’s modulus of CS/PG 0.5% (84 ± 4.71 MPa) was 7.5-fold lower as compared to CS/PEO (662 ± 15.18 MPa, p < 0.0001). Contact angle measurements showed that both GO-COOH content and crosslinking step influenced the surface wettability of scaffolds, leading to materials with ~1.25-fold higher hydrophobicity. The in vitro cytocompatibility assessment showed that the designed nanofibrous scaffolds showed a reasonable cellular proliferation level after 72 h of contact with the fibroblast cells.

scholarly journals Effect of Annealing Temperature on Structural and, Morphological Properties of Zno Thins Films

2021 ◽  
Author(s):  
Moustafa Debbab ◽  
Nassera Ghellai ◽  
Meymoun Belaoui ◽  
Chafiaa Yaddadene ◽  
Malika Berouaken ◽  
...  
Keyword(s):  
Contact Angle ◽  
Annealing Temperature ◽  
Morphological Properties ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Diffraction Angle ◽  
Xrd Patterns

Abstract In this work, thins films of zinc oxide were deposited on n-type silicon substrates by chemical electrodeposition. The effect of annealing temperature from 200 ° C to 600 ° C, with a step of 100 ° C, on the structural and morphological properties of ZnO layers has been studied. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and contact angle measurements were used to characterize the morphology and structure of ZnO without and with annealing. The XRD patterns of unannealed ZnO thins films indicate the presence of three intense peaks along (100), (002) and (101) planes, while for the annealed ZnO layers the XRD patterns show also the three major peaks but the intensity of these peaks is increased except for a temperature of 600 ° C where is decreased. The comparison of the XRD patterns of the ZnO layers without and with annealing, reveal a shift in the 2θ diffraction angle, the calculation of the crystallinity confirms the obtained results. The contact angle measurements indicate that the ZnO layers without and with annealing at 200 °C are hydrophobic, the surface of the ZnO layer becomes hydrophilic at annealing temperatures exceeding 300 ° C. Finally, SEM images show the change in structure from a sand rose shape to a granular structure, confirming the XRD and contact angle results.

Effect of different exposure times on physicochemical, mechanical and biological properties of PGS scaffolds treated with plasma of iodine-doped polypyrrole

2020 ◽  
Vol 35 (4-5) ◽  
pp. 485-499
Author(s):  
Gaspar Eduardo Martín-Pat ◽  
Nayeli Rodriguez-Fuentes ◽  
J Manuel Cervantes-Uc ◽  
Raúl Rosales-Ibáñez ◽  
Hugo Joel Carrillo-Escalante ◽  
...  
Keyword(s):  
Cell Viability ◽  
Exposure Time ◽  
Direct Contact ◽  
Plasma Reactor ◽  
Biological Properties ◽  
Sem Analysis ◽  
Water Contact ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
High Cytotoxicity

Polyglycerol sebacate (PGS) scaffolds obtained using a leaching technique were modified with iodine-doped polypyrrole (PPy-I) in a plasma reactor in order to study the effect of exposure time on the cell viability of hDPSCs. SEM analysis showed the formation and growth of PPy-I particles as the exposure time was increased, while FTIR and XPS analysis revealed the presence of -NH- and N+ groups in the chemical composition of the surfaces, relating to the increase in the amount of PPY-I particles. The water contact angle measurements showed an increase in the scaffold’s hydrophilicity with greater exposure times which was also attributed to the rising of PPy-I particles. It was also observed that PPy-I promotes the rigidity of the treated PGS scaffolds. when in direct contact with treated PGS scaffolds, cell viability improved with respect to non-treated scaffolds, however only at shorter time exposures. Extracts of plasma-treated PGS scaffolds showed high cytotoxicity as the time exposure to plasma treatment was increased.

The diamond-solution interface: the surface energy of hydrogen terminated nanocrystalline CVD diamond derived from contact angle measurements

2011 ◽  
Vol 1362 ◽  
Author(s):  
Stoffe D. Janssens ◽  
Sien Drijkoningen ◽  
Marc Saitner ◽  
Hans-Gerd Boyen ◽  
Ken Haenen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Photoelectron Spectroscopy ◽  
Microwave Plasma ◽  
Sessile Drop ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Silicon Substrates ◽  
Angle Measurements ◽  
Contact Angle Measurements

ABSTRACTIn this work, a determination of the surface energy for hydrogen terminated nanocrystalline diamond grown with microwave plasma enhanced chemical vapor deposition is presented. Five identical hydrogen terminated nanocrystalline diamond layers of ~150 nm thick are deposited on silicon substrates and examined with X-ray photoelectron spectroscopy to determine the surface groups and possible surface contaminations. In order to evaluate the surface energy, contact angle measurements are performed using the sessile drop method in combination with data analysis based on the ‘Owens, Wendt, Rabel and Kaelble’ method. Four different experimental approaches to evaluate the surface energy of hydrogen terminated nanocrystalline diamond are discussed.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

scholarly journals Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3888
Author(s):  
Johanna Maier ◽  
Christian Vogel ◽  
Tobias Lebelt ◽  
Vinzenz Geske ◽  
Thomas Behnisch ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Polyamide 6 ◽  
Thermoplastic Composites ◽  
Efficient Production ◽  
Angle Measurements ◽  
Small Series ◽  
Contact Angle Measurements ◽  
Static Tensile ◽  
Pre Treatment ◽  
Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

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