scholarly journals Cu∥-loaded polydopamine coatings with in situ nitric oxide generation function for improved hemocompatibility

2020 ◽  
Vol 7 (2) ◽  
pp. 153-160
Author(s):  
Lei Zhou ◽  
Xin Li ◽  
Kebing Wang ◽  
Fangyu Shen ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Contact Angles ◽  
Blood System ◽  
Signal Molecule ◽  
Water Contact ◽  
No Donor ◽  
Contact Materials ◽  
Force Microscopy ◽  
Composition And Structure ◽  
Pathological Environment

Abstract NO is the earliest discovered gas signal molecule which is produced by normal healthy endothelial cells, and it has many functions, such as maintaining cardiovascular homeostasis, regulating vasodilation, inhibiting intimal hyperplasia and preventing atherosclerosis in the blood system. Insufficient NO release is often observed in the pathological environment, for instance atherosclerosis. It was discovered that NO could be released from the human endogenous NO donor by many compounds, and these methods can be used for the treatment of certain diseases in the blood system. In this work, a series of copper-loaded polydopamine (PDA) coatings were produced through self-polymerization time for 24, 48 and 72 h. The chemical composition and structure, coating thickness and hydrophilicity of the different copper-loaded PDA coatings surfaces were characterized by phenol hydroxyl quantitative, X-ray photoelectron spectroscopy, ellipsometry atomic force microscopy and water contact angles. The results indicate that the thickness and the surface phenolic hydroxyl density of the PDA coatings increased with the polymerization time.This copper-loaded coating has glutathione peroxidase-like activity, and it has the capability of catalyzing NO releasing from GSNO. The surface of the coating showed desirable hemocompatibility, the adhesion and activation of platelets were inhibited on the copper-loaded coatings. At the same time, the formation of the thrombosis was also suppressed. These copper-loaded PDA coatings could provide a promising platform for the development of blood contact materials.

scholarly journals Synthesis of amphiphilic ABA triblock oligomer via ATRP and its surface properties

2017 ◽  
Vol 95 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Lei Wang ◽  
Shaoqing Wen ◽  
Zhanxiong Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Microphase Separation ◽  
Gel Permeation Chromatography ◽  
Contact Angles ◽  
Chemical Compositions ◽  
Water Contact ◽  
Force Microscopy ◽  
Atomic Force ◽  
Poly Ethylene ◽  
Magnetic Resonances

A series of novel amphiphilic ABA-type poly(tridecafluorooctylacrylate)-poly(ethylene glycol)-poly(tridecafluorooctylacrylate) (henceforth referred to as p-TDFA-PEG-p-TDFA) triblock oligomers were successfully synthesized via atom transfer radical polymerization (ATRP) using well-defined Br-PEG-Br as macroinitiator and copper as catalyst. The block oligomers were characterized by Fourier transform infrared (FTIR) spectroscopy and 1H and 19F nuclear magnetic resonances (NMR). Gel permeation chromatography (GPC) showed that the block oligomers have been obtained with narrow molecular weight distributions of 1.22–1.33. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the attachment of p-TDFA-PEG-p-TDFA onto the silicon substrate, together with the chemical compositions of p-TDFA-PEG-p-TDFA. The wetabilities of the oligomer films were measured by water contact angles (CAs). Water CAs of p-TDFA-PEG-p-TDFA film were measured and their morphologies were tested by atomic force microscopy (AFM). The result showed that the CAs of the oligomer films, which possess fluoroalkyl groups assembled on the outer surface, increase after heating due to the migration of fluoroalkyl groups and the resulted microphase separation of the p-TDFA-PEG-p-TDFA.

scholarly journals P4VP Modified Zwitterionic Polymer for the Preparation of Antifouling Functionalized Surfaces

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 706 ◽  
Author(s):  
Chaoqun Wu ◽  
Yudan Zhou ◽  
Haitao Wang ◽  
Jianhua Hu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cell Attachment ◽  
Raft Polymerization ◽  
Polymer Brush ◽  
Contact Angles ◽  
Polymerization Process ◽  
Water Contact ◽  
Zwitterionic Polymers ◽  
Ito Glass ◽  
Zwitterionic Polymer

Zwitterionic polymers are suitable for replacing poly(ethylene glycol) (PEG) polymers because of their better antifouling properties, but zwitterionic polymers have poor mechanical properties, strong water absorption, and their homopolymers should not be used directly. To solve these problems, a reversible-addition fragmentation chain transfer (RAFT) polymerization process was used to prepare copolymers comprised of zwitterionic side chains that were attached to an ITO glass substrate using spin-casting. The presence of 4-vinylpyridine (4VP) and zwitterion chains on these polymer-coated ITO surfaces was confirmed using 1H NMR, FTIR, and GPC analyses, with successful surface functionalization confirmed using water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) studies. Changes in water contact angles and C/O ratios (XPS) analysis demonstrated that the functionalization of these polymers with β-propiolactone resulted in hydrophilic mixed 4VP/zwitterionic polymers. Protein adsorption and cell attachment assays were used to optimize the ratio of the zwitterionic component to maximize the antifouling properties of the polymer brush surface. This work demonstrated that the antifouling surface coatings could be readily prepared using a “P4VP-modified” method, that is, the functionality of P4VP to modify the prepared zwitterionic polymer. We believe these materials are likely to be useful for the preparation of biomaterials for biosensing and diagnostic applications.

Tailoring surface properties of functionalized graphene papers aiming to enzyme immobilization

2021 ◽  
Author(s):  
Jéssica Luzardo ◽  
Douglas Aguiar ◽  
Alexander Silva ◽  
Sanair Oliveira ◽  
Braulio Archanjo ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Enzyme Stability ◽  
Immobilized Enzymes ◽  
Free Enzyme ◽  
X Ray ◽  
Force Microscopy ◽  
Enzyme Solution ◽  
Atomic Force ◽  
Composition And Structure

The use of enzymes as catalysts requires recovery and reuse to make the process viable. Enzymatic immobilization changes enzyme stability, activity, and specificity. It is very important to explore new substrates for immobilization with appropriate composition and structure to improve the efficiency of the immobilized enzymes. This work explores the use of two different graphene oxide papers, one produced by oxidation route (GO) and the other by electrochemical synthesis (EG), aiming for β-galactosidase immobilization. The chemical and structural properties of these two papers were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Atomic force microscopy images showed that EG paper ensured more efficient immobilization of the enzymes on the surface of the paper. Cyclic voltammetry was used to monitor the reaction of conversion of lactose to glucose in the free enzyme solution and graphene paper immobilized enzyme solutions. The cyclic voltammetry analysis showed that immobilized enzymes on GO paper showed an improvement in the activity of β-galactose when compared to free enzyme solution, as well as enzyme immobilized on a glassy carbon electrode.

scholarly journals Superhydrophilic Coating with Antibacterial and Oil-Repellent Properties via NaIO4-Triggered Polydopamine/Sulfobetaine Methacrylate Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2008
Author(s):  
Hsiu-Wen Chien ◽  
Hong-Yu Lin ◽  
Chau-Yi Tsai ◽  
Tai-Yu Chen ◽  
Wei-Nian Chen
Keyword(s):  
Surface Modification ◽  
Photoelectron Spectroscopy ◽  
Deposition Process ◽  
Water Contact ◽  
Water Separation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Oil Water Separation ◽  
One Step ◽  
Oil Repellent

Superhydrophilic coatings have been widely used for the surface modification of membranes or biomedical devices owing to their excellent antifouling properties. However, simplifying the modification processes of such materials remains challenging. In this study, we developed a simple and rapid one-step co-deposition process using an oxidant trigger to fabricate superhydrophilic surfaces based on dopamine chemistry with sulfobetaine methacrylate (SBMA). We studied the effect of different oxidants and SBMA concentrations on surface modification in detail using UV–VIS spectrophotometry, dynamic light scattering, atomic force microscopy, X-ray photoelectron spectroscopy, and surface plasmon resonance. We found that NaIO4 could trigger the rate of polymerization and the optimum ratio of dopamine to SBMA is 1:25 by weight. This makes the surface superhydrophilic (water contact angle < 10°) and antifouling. The superhydrophilic coating, when introduced to polyester membranes, showed great potential for oil/water separation. Our study provides a complete description of the simple and fast preparation of superhydrophilic coatings for surface modification based on mussel-inspired chemistry.

scholarly journals Surface Properties of Pine Scrimber Panels with Varying Density

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 397 ◽  
Author(s):  
Jinguang Wei ◽  
Qiuqin Lin ◽  
Yahui Zhang ◽  
Wenji Yu ◽  
Chung-Yun Hse ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Lower Surface ◽  
Contact Angles ◽  
High Density ◽  
Water Contact ◽  
Change Rate ◽  
Hydrophilic Material ◽  
Wood Grain

Coating quality for scrimber products against exterior conditions is largely dependent on the surface properties. The wettability, morphology, and chemical composition of pine scrimber surfaces were investigated to better understand the surface properties. The scrimber was found to be a hydrophilic material because the water contact angles were less than 90°. The panels with a density of 1.20 g/cm3 had the largest angle change rate (k = 0.212). As the panel density increased, the instantaneous contact angle of each test liquid (i.e., water, formamide, and diiodomethane) on the panels decreased, and so did surface free energy. Panels with higher density showed lower surface roughness. Surface roughness across the wood grain was greater than that along the grain. SEM observations showed the high-density panels had a smoother surface with fewer irregular grooves in comparison with the low-density panels. X-ray photoelectron spectroscopy (XPS) analysis indicated that more unoxygenated groups appeared on the surface of high-density panels.

scholarly journals Functionalization of Neutral Polypropylene by Using Low Pressure Plasma Treatment: Effects on Surface Characteristics and Adhesion Properties

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 202 ◽  
Author(s):  
Chiara Mandolfino ◽  
Enrico Lertora ◽  
Carla Gambaro ◽  
Marco Pizzorni
Keyword(s):  
Surface Morphology ◽  
Photoelectron Spectroscopy ◽  
Polymeric Materials ◽  
Low Pressure ◽  
Contact Angles ◽  
Bonded Joints ◽  
Water Contact ◽  
Adhesion Properties ◽  
Pressure Plasma ◽  
Low Pressure Plasma

Polyolefins are considered among the most difficult polymeric materials to treat because they have poor adhesive properties and high chemical barrier responses. In this paper, an in-depth study is reported for the low pressure plasma (LPP) treatment of neutral polypropylene to improve adhesion properties. Changes in wettability, chemical species, surface morphology and roughness of the polypropylene surfaces were evaluated by water contact angle measurement, X-ray photoelectron spectroscopy and, furthermore, atomic force microscopy (AFM). Finally, the bonded joints were subjected to tensile tests, in order to evaluate the practical effect of changes in adhesion properties. The results indicate that plasma is an effective treatment for the surface preparation of polypropylene for the creation of bonded joints: contact angles decreased significantly depending on the plasma-parameter setup, surface morphology was also found to vary with plasma power, exposure time and working gas.

The Use of X-Ray Photoelectron Spectroscopy for the Study of Oral Streptococcal Cell Surfaces

1997 ◽  
Vol 11 (4) ◽  
pp. 388-394 ◽  
Author(s):  
H.C. Van Der Mei ◽  
H.J. Busscher
Keyword(s):  
Cell Surface ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Contact Angles ◽  
Microbial Cell ◽  
Cell Surfaces ◽  
Water Contact ◽  
X Ray

Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and consequently do not yield information about the composition of the outermost cell surface. X-ray photoelectron spectroscopy (XPS) measures the elemental composition of the outermost cell surfaces of micro-organisms. The technique requires freeze-drying of the organisms, but, nevertheless, elemental surface concentration ratios of oral streptococcal cell surfaces with peritrichously arranged surface structures showed good relationships with physicochemical properties measured under physiological conditions, such as zeta potentials. Isoelectric points ap-peared to be governed by the relative abundance of oxygen- and nitrogen-containing groups on the cell surfaces. Also, the intrinsic microbial cell-surface hydrophobicity by water contact angles related to the cell-surface composition as by XPS and was highest for strains with an elevated isoelectric point. Inclusion of elemental surface compositions for tufted streptococcal strains caused deterioration of the relationships found. Interestingly, hierarchical cluster analysis on the basis of the elemental surface compositions revealed that, of 36 different streptococcal strains, only four S. rattus as well as nine S. mitis strains were located in distinct groups, well separated from the other streptococcal strains, which were all more or less mixed in one group.

Diamond-Like Carbon Films for Silicon Passivation in Microelectromechanical Devices

1995 ◽  
Vol 383 ◽  
Author(s):  
M. R. Houston ◽  
R. T. Howe ◽  
K Komvopoulos ◽  
R. Maboudian
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Microelectromechanical Systems ◽  
Adhesion Force ◽  
Contact Angles ◽  
Vacuum Arc ◽  
Diamond Like Carbon ◽  
Adhesion Forces ◽  
Water Contact

ABSTRACTThe surface properties of diamond-like carbon (DLC) films deposited by a vacuum arc technique on smooth silicon wafers are presented with specific emphasis given to stiction reduction in microelectromechanical systems (MEMS). The low deposition temperatures afforded by the vacuum arc technique should allow for easy integration of the DLC films into the current fabrication process of typical surface micromachines by means of a standard lift-off processing technique. Using X-ray photoelectron spectroscopy (XPS), contact angle analysis, and atomic force microscopy (AFM), the surface chemistry, microroughness, hydrophobicity, and adhesion forces of DLC-coated Si(100) surfaces were measured and correlated to the measured water contact angles. DLC films were found to be extremely smooth and possess a water contact angle of 87°, which roughly corresponds to a surface energy of 22 mJ/m2. It is shown that the pull-off forces measured by AFM correlate well with the predicted capillary forces. Pull-off forces are reduced on DLC surfaces by about a factor of five compared to 10 nN pull-off forces measured on the RCA-cleaned silicon surfaces. In the absence of meniscus forces, the overall adhesion force is expected to decrease by over an order of magnitude to the van der Waals attractive force present between two DLC-coated surfaces- To further improve the surface properties of DLC, films were exposed to a fluorine plasma which increased the contact angle to 99° and lowered the pull-off force by approximately 20% over that obtained with as-deposited DLC. The significance of these results is discussed with respect to stiction reduction in micromachines.

scholarly journals The Covalent Tethering of Poly(ethylene glycol) to Nylon 6 Surface via N,N′-Disuccinimidyl Carbonate Conjugation: A New Approach in the Fight against Pathogenic Bacteria

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2181
Author(s):  
Sumita Swar ◽  
Veronika Máková ◽  
Ivan Stibor
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pathogenic Bacteria ◽  
Polymer Surface ◽  
Nylon 6 ◽  
Secondary Amines ◽  
Surface Immobilization ◽  
Water Contact ◽  
Force Microscopy ◽  
Poly Ethylene

Different forms of unmodified and modified Poly(ethylene glycols) (PEGs) are widely used as antifouling and antibacterial agents for biomedical industries and Nylon 6 is one of the polymers used for biomedical textiles. Our recent study focused on an efficient approach to PEG immobilization on a reduced Nylon 6 surface via N,N′–disuccinimidyl carbonate (DSC) conjugation. The conversion of amide functional groups to secondary amines on the Nylon 6 polymer surface was achieved by the reducing agent borane-tetrahydrofuran (BH3–THF) complex, before binding the PEG. Various techniques, including water contact angle and free surface energy measurements, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the desired surface immobilization. Our findings indicated that PEG may be efficiently tethered to the Nylon 6 surface via DSC, having an enormous future potential for antifouling biomedical materials. The bacterial adhesion performances against S. aureus and P. aeruginosa were examined. In vitro cytocompatibility was successfully tested on pure, reduced, and PEG immobilized samples.

scholarly journals Adhesion to Bile Drain Materials and Physicochemical Surface Properties of Enterococcus faecalis Strains Grown in the Presence of Bile

2002 ◽  
Vol 68 (8) ◽  
pp. 3855-3858 ◽  
Author(s):  
Karola Waar ◽  
Henny C. van der Mei ◽  
Hermie J. M. Harmsen ◽  
John E. Degener ◽  
Henk J. Busscher
Keyword(s):  
Surface Properties ◽  
Enterococcus Faecalis ◽  
Photoelectron Spectroscopy ◽  
Surface Protein ◽  
Lower Surface ◽  
Contact Angles ◽  
Surface Proteins ◽  
Water Contact ◽  
Zeta Potentials ◽  
Aggregation Substance

ABSTRACT The aim of this study is to determine whether growth in the presence of bile influences the surface properties and adhesion to hydrophobic bile drain materials of Enterococcus faecalis strains expressing aggregation substance (Agg) or enterococcal surface protein (Esp), two surface proteins that are associated with infections. After growth in the presence of bile, the strains were generally more hydrophobic by water contact angles and the zeta potentials were more negative than when the strains were grown in the absence of bile. Nitrogen was found in lower surface concentrations upon growth in the presence of bile, whereas higher surface concentrations of oxygen were measured by X-ray photoelectron spectroscopy. Moreover, an up to twofold-higher number of bacteria adhered after growth in bile for E. faecalis not expressing Agg or Esp and E. faecalis with Esp on its surface. E. faecalis expressing Agg did not adhere in higher numbers after growth in bile, possibly because they mainly adhere through positive cooperativity and less through direct interactions with a substratum surface. Since adhesion of bacteria is the first step in biomaterial-centered infection, it can be concluded that growth in bile increases the virulence of E. faecalis.

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