scholarly journals Electrochemical Polymerization of PEDOT–Graphene Oxide–Heparin Composite Coating for Anti-fouling and Anti-clotting of Cardiovascular Stents

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1520 ◽  
Author(s):  
Yang ◽  
Tsou ◽  
Hsiao ◽  
Cheng ◽  
Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Graphene Oxide ◽  
Blood Clotting ◽  
Electrochemical Polymerization ◽  
Composite Coatings ◽  
3T3 Cells ◽  
Clotting Time ◽  
Cardiovascular Stents ◽  
Electrochemical Copolymerization ◽  
Steel Substrates

ABSTRACT: In this study, a novel hemocompatible coating on stainless steel substrates was prepared by electrochemically copolymerizing 3,4-ethylenedioxythiophene (EDOT) with graphene oxide (GO), polystyrene sulfonate (PSS), or heparin (HEP) on SUS316L stainless steel, producing an anti-fouling (anti-protein adsorption and anti-platelet adhesion) surface to avoid the restenosis of blood vessels. The negative charges of GO, PSS, and HEP repel negatively charged proteins and platelets to achieve anti-fouling and anti-clotting. The results show that the anti-fouling capability of the poly(3,4-ethylenedioxythiophene) (PEDOT)/PSS coating is similar to that of the PEDOT/HEP coating. The anti-fouling capability of PEDOT/GO is higher than those of PEDOT/HEP and PEDOT/PSS. The reason for this is that GO exhibits negatively charged functional groups (COO−). The highest anti-fouling capability was found with the PEDOT/GO/HEP coating, indicating that electrochemical copolymerization of PEDOT with GO and HEP enhances the anti-fouling capability. Furthermore, the biocompatibility of the PEDOT coatings was tested with 3T3 cells for 1–5 days. The results show that all PEDOT composite coatings exhibited biocompatibility. The blood clotting time (APTT) of PEDOT/GO/HEP was prolonged to 225 s, much longer than the 40 s of pristine SUS316L stainless steel (the control), thus greatly improving the anti-blood-clotting capability of cardiovascular stents.

scholarly journals Fabrication and Characterization of Zein/Hydroxyapatite Composite Coatings for Biomedical Applications

Surfaces ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Yusra Ahmed ◽  
Muhammad Yasir ◽  
Muhammad Atiq Ur Rehman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Sem Images ◽  
Taguchi Design Of Experiments ◽  
Hydrophilic Nature ◽  
Strong Adhesion ◽  
Steel Substrates

Stainless steel is renowned for its wide use as a biomaterial, but its relatively high corrosion rate in physiological environments restricts many of its clinical applications. To overcome the corrosion resistance of stainless steel bio-implants in physiological environments and to improve its osseointegration behavior, we have developed a unique zein/hydroxyapatite (HA) composite coating on a stainless steel substrate by Electrophoretic Deposition (EPD). The EPD parameters were optimized using the Taguchi Design of experiments (DoE) approach. The EPD parameters, such as the concentration of bio-ceramic particles in the polymer solution, applied voltage and deposition time were optimized on stainless steel substrates by applying a mixed design orthogonal Taguchi array. The coatings were characterized by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and wettability studies. SEM images and EDX results indicated that the zein/HA coating was successfully deposited onto the stainless steel substrates. The wettability and roughness studies elucidated the mildly hydrophilic nature of the zein/HA coatings, which confirmed the suitability of the developed coatings for biomedical applications. Zein/HA coatings improved the corrosion resistance of bare 316L stainless steel. Moreover, zein/HA coatings showed strong adhesion with the 316L SS substrate for biomedical applications. Zein/HA developed dense HA crystals upon immersion in simulated body fluid, which confirmed the bone binding ability of the coatings. Thus the zein/HA coatings presented in this study have a strong potential to be considered for orthopedic applications.

Electrophoretic Deposition of PEEK-TiO2 Composite Coatings on Stainless Steel

2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Electrophoretic Deposition ◽  
Biomedical Applications ◽  
316L Stainless Steel ◽  
Treatment Process ◽  
Composite Coatings ◽  
Heat Treatment Process ◽  
Steel Substrates ◽  
Scanning Electron

Electrophoretic deposition (EPD) has been successfully used to deposit composite coatings composed of polyetheretherketone (PEEK) and titanium dioxide (TiO2) nanoparticles on 316L stainless steel substrates. The suspensions of TiO2 nanoparticles and PEEK microparticles for EPD were prepared in ethanol. PEEK-TiO2 composite coatings were optimized using suspensions containing 6wt% PEEK-TiO2 in ethanol with a 3:1 ratio of PEEK to TiO2 in weight and by applying a potential difference of 30 V for 1 minute. A heat-treatment process of the optimized PEEK-TiO2 composite coatings was performed at 335°C for 30 minutes with a heating rate of 10°Cminto densify the deposits. The EPD coatings were microstructurally evaluated by scanning electron microscopy (SEM). It was demonstrated that EPD is a convenient and rapid method to fabricate PEEK/TiO2 coatings on stainless steel which are interesting for biomedical applications.

High temperature friction and wear properties of graphene oxide/polytetrafluoroethylene composite coatings deposited on stainless steel

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5977-5987 ◽  
Author(s):  
N. Nemati ◽  
M. Emamy ◽  
S. Yau ◽  
J.-K. Kim ◽  
D.-E. Kim
Keyword(s):  
Stainless Steel ◽  
Graphene Oxide ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Composite Coatings ◽  
Friction Material ◽  
Wear Properties ◽  
Low Friction ◽  
Solid Lubricant Coating ◽  
Friction And Wear Properties

Polytetrafluoroethylene (PTFE) coating is known as a low friction material that is often used as a solid lubricant coating.

scholarly journals PDC Glass/Ceramic Coatings Applied to Differently Pretreated AISI441 Stainless Steel Substrates

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 629 ◽  
Author(s):  
Milan Parchovianský ◽  
Ivana Parchovianská ◽  
Peter Švančárek ◽  
Günter Motz ◽  
Dušan Galusek
Keyword(s):  
Stainless Steel ◽  
Bond Coat ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Spray Coating ◽  
Ceramic Coatings ◽  
Strong Adhesion ◽  
Cleaning Procedures ◽  
Small Cracks ◽  
Steel Substrates

In this work, the influence of different cleaning procedures on adhesion of composite coatings containing passive ceramic and commercial glasses was investigated. Two compositions (C2c, D2-PP) of double-layer polymer-derived ceramic (PDC) coating systems, composed from bond coat and a top coat, were developed. In order to obtain adherent coatings, stainless steel substrates were cleaned by four different cleaning procedures. The coatings were then deposited onto the steel substrate via spray coating. Pretreatment by subsequent ultrasonic cleaning in acetone, ethanol and deionised water (procedure U) was found to be the most effective, and the resultant C2c and D2-PP coatings, pyrolysed at 850 °C, indicated strong adhesion without delamination or cracks, propagating at the interface steel/bond coat. In the substrate treated by sandblasting and chemical etching, small cracks in the bond coat were observed under the same pyrolysis conditions. After oxidation tests, all coatings, except for those subjected to the U-treated substrates, showed significant cracking in the bond coat. The D2-PP coatings were denser than C2c, indicating better protection of the substrate.

Hydroxyapatite and Titanium Composite Coatings on Austenitic Stainless Steel Substrates Using Direct Material Deposition

2013 ◽  
Vol 773-774 ◽  
pp. 602-615
Author(s):  
Muhammad Rakib Mansur ◽  
James Wang ◽  
Christopher C. Berndt
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Composite Coatings ◽  
Power Level ◽  
Traverse Speed ◽  
Stainless Steel 316L ◽  
Average Roughness ◽  
Material Deposition ◽  
Good Biocompatibility ◽  
Steel Substrates

Hydroxyapatite (HA) and titanium composite coatings, which demonstrate good biocompatibility and load bearing capacity, are important in the topical area of prosthetics. In this study, hydroxyapatite and titanium composite coatings were deposited on austenitic stainless steel (316L) substrates using the Direct Material Deposition (DMD) technique. The microstructures were characterized using optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Surface topography and roughness were assessed by SEM and profilometry, while Raman microscopy was employed to determine the nature of HA in the feedstock. The results indicate that average roughness increases with traverse speed and depends significantly on the power level. The crack orientation was found to be sensitive to traverse speed, while the number of cracks was related to the power level. Porosity decreased as the power level increased.

scholarly journals Corrosion Properties of S-Phase/Cr2N Composite Coatings Deposited on Austenitic Stainless Steel

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 266
Author(s):  
Sebastian Fryska ◽  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nitrogen Content ◽  
Polarization Resistance ◽  
Composite Coatings ◽  
Nitrogen Concentration ◽  
S Phase ◽  
Initial Surface ◽  
Corrosion Properties ◽  
Steel Substrates

In order to study the suitability of the S-phase layers as the interlayer for Cr2N chromium nitride coatings, a number of composite coatings were deposited by the reactive magnetron sputtering (RMS) method on austenitic steel substrates with various initial surface conditions (as delivered and polished) and their corrosion resistance was assessed. Coatings with S-phase interlayer were deposited at three different nitrogen contents in the working atmosphere (15%, 30%, and 50%), which influenced the nitrogen concentration in the S-phase. Coatings with chromium, as a traditional interlayer to improve adhesion, and uncoated austenitic stainless steel were used as reference materials. Detailed microstructural and phase composition studies of the coatings were carried out by means of scanning electron microscopy (SEM), optical microscopy (LM), and X-ray diffraction (XRD) and were discussed in the context of results of corrosion tests carried out with the use of the potentiodynamic polarization method conducted in a 3% aqueous solution of sodium chloride (NaCl). The performed tests showed that the electrochemical potential of the S-phase/Cr2N composite coatings is similar to that of Cr/Cr2N coatings. It was also observed that the increase in the nitrogen content in the S-phase interlayer causes an increase in the polarization resistance of the S-phase/Cr2N composite coating. Moreover, with a higher nitrogen content in the S-phase interlayer, the polarization resistance of the S-phase/Cr2N coating is higher than for the Cr/Cr2N reference coating. All the produced composite coatings showed better corrosion properties in relation to the uncoated austenitic stainless steel.

scholarly journals Anti-Bacterial and Anti-Fouling Capabilities of Poly(3,4-Ethylenedioxythiophene) Derivative Nanohybrid Coatings on SUS316L Stainless Steel by Electrochemical Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1467 ◽  
Author(s):  
Chuan-Chih Hsu ◽  
Yu-Wei Cheng ◽  
Che-Chun Liu ◽  
Xin-Yao Peng ◽  
Ming-Chi Yung ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Negative Charge ◽  
Electrochemical Polymerization ◽  
Inhibition Zone ◽  
Lower Surface ◽  
Water Contact ◽  
Force Microscopy ◽  
Cardiovascular Stents ◽  
Atomic Force

We have successfully fabricated poly(3,4-ethylenedioxythiophene) (PEDOT) derivative nanohybrid coatings on flexible SUS316L stainless steel by electrochemical polymerization, which can offer anti-fouling and anti-bacterial capabilities. PEDOT derivative nanohybrids were prepared from polystyrene sulfonates (PSS) and graphene oxide (GO) incorporated into a conducting polymer of PEDOT. Additionally, the negative charge of the PEDOT/GO substrate was further modified by poly-diallyldimethylammonium chloride (PDDA) to form a positively charged surface. These PEDOT derivative nanohybrid coatings could provide a straightforward means of controlling the surface energy, roughness, and charges with the addition of various derivatives in the electrochemical polymerization and electrostatically absorbed process. The characteristics of the PEDOT derivative nanohybrid coatings were evaluated by Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle, and surface potential (zeta potential). The results show that PEDOT/PSS and PEDOT/GO nanohybrid coatings exhibit excellent anti-fouling capability. Only 0.1% of bacteria can be adhered on the surface due to the lower surface roughness and negative charge surface by PEDOT/PSS and PEDOT/GO modification. Furthermore, the anti-bacterial capability (7 mm of inhibition zone) was observed after adding PDDA on the PEDOT/GO substrates, suggesting that the positive charge of the PEDOT/GO/PDDA substrate can effectively kill bacteria (Staphylococcus aureus). Given their anti-fouling and anti-bacterial capabilities, PEDOT derivative nanohybrid coatings have the potential to be applied to biomedical devices such as cardiovascular stents and surgical apparatus.

Electrophoretic Co-Deposition of Chitosan and Graphene Oxide Results in Antibacterial Coatings for Medical Applications

2015 ◽  
Vol 654 ◽  
pp. 176-182 ◽  
Author(s):  
Anke Lisa Metze ◽  
Fatemehsadat Pishbin ◽  
Mary P. Ryan ◽  
Sigrid Seuss ◽  
Mani Diba ◽  
...  
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Graphene Oxide ◽  
Polymer Matrix ◽  
Electrophoretic Deposition ◽  
Composite Coatings ◽  
Medical Applications ◽  
Antibacterial Studies ◽  
Graphene Oxide Sheets ◽  
Roughness Measurements

Chitosan – graphene oxide (GO) composite coatings intended for antibacterial applications were obtained by cathodic electrophoretic deposition (EPD) on stainless steel. The coatings were characterized using SEM, FTIR, contact angle and roughness measurements and by antibacterial studies againstE.coli. The coating was observed to consist of a polymer matrix with embedded, agglomerated graphene oxide sheets. A decrease in bacteria cell viability of at least 50 % was measured on the chitosan – GO surface in comparison to uncoated stainless steel.

Kinetic Aspects of the Interaction of Blood Clotting Enzymes

1965 ◽  
Vol 13 (01) ◽  
pp. 155-175 ◽  
Author(s):  
H. C Hemker ◽  
P.W Hemker ◽  
E. A Loeliger
Keyword(s):  
Kinetic Analysis ◽  
Enzyme Kinetics ◽  
Blood Clotting ◽  
Enzyme System ◽  
Enzyme Kinetic ◽  
Clotting Time ◽  
Standard Methods

SummaryApplication of the methods of enzyme-kinetic analysis to the results of clotting tests is feasible and can yield useful results. However, the standard methods of enzyme kinetics are not applicable without modifications imposed by the peculiarities of the blood-clotting enzyme system. The influence of the following complicating circumstances is calculated :1. Substrate is not present in excess.2. Only relative measures exist for concentrations of substrate or enzymes.3. Enzymes and substrates are often added together.4. Reagents are not pure.5. Clotting-time is our only measure for clotting-velocity.Formulas are deduced, which makes it possible to recognize the effect of these complications.

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