scholarly journals Preparation of modified polysulfone material decorated by sulfonated citric chitosan for haemodialysis and its haemocompatibility

2021 ◽  
Vol 8 (9) ◽  
pp. 210462
Author(s):  
Bingxian Lin ◽  
Kaiming Liu ◽  
Yunren Qiu
Keyword(s):  
Contact Angle ◽  
Active Sites ◽  
Platelet Adhesion ◽  
Activated Partial Thromboplastin Time ◽  
Thrombin Time ◽  
Chloroacetyl Chloride ◽  
Water Contact ◽  
H Nmr ◽  
Plasma Recalcification Time ◽  
Recalcification Time

Polysulfone (PSF) works potentially in haemodialysis due to its great mechanical and chemical stability, but performs poorly in haemocompatibility. For promoting the unpleasant haemocompatibility, sulfonated citric chitosan (SCACS) with the structure and groups similar to heparin was primarily synthesized by acylation and sulfonation. Furthermore, the chloroacylated PSF was pretreated by electrophilic chloroacetyl chloride to achieve more active sites for further reaction; the following membranes underwent the amination and were named amination polysulfone (AMPSF) membranes. Moreover, SCACS with abundant carboxyl and sulfonic groups was covalently grafted at the surface of pretreated PSF membranes, called PSF-SCACS membranes. The PSF-SCACS membranes were successfully synthesized and characterized by 1 H NMR, ATR-FTIR and XPS. In addition, the water contact angle of PSF-SCACS membranes decreased by 47° and the morphologies of the membranes changed little compared with the unmodified PSF membranes. The haemocompatible testing results, including protein adsorption, platelet adhesion, haemolysis rate, plasma recalcification time, activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT), demonstrated that the PSF-SCACS membranes possessed excellent haemocompatible performances, and SCACS played an important role in the modification.

scholarly journals Heparinized Polyurethane Surface Via a One-Step Photografting Method

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 758 ◽  
Author(s):  
Zhangshuan Liu ◽  
Liming Fang ◽  
Guillaume Delaittre ◽  
Yu Ke ◽  
Gang Wu
Keyword(s):  
Platelet Adhesion ◽  
Antithrombin Iii ◽  
Thrombin Time ◽  
Binding Ability ◽  
Aryl Azide ◽  
One Step ◽  
Heparin Derivatives ◽  
Low Efficiency ◽  
Plasma Recalcification Time ◽  
Recalcification Time

Traditional methods using coupling chemistry for surface grafting of heparin onto polyurethane (PU) are disadvantageous due to their generally low efficiency. In order to overcome this problem, a quick one-step photografting method is proposed here. Three heparin derivatives incorporating 0.21, 0.58, and 0.88 wt% pendant aryl azide groups were immobilized onto PU surfaces, leading to similar grafting densities of 1.07, 1.17, and 1.13 μg/cm2, respectively, yet with increasing densities of anchoring points. The most negatively charged surface and the maximum binding ability towards antithrombin III were found for the heparinized PU with the lowest amount of aryl azide/anchor sites. Furthermore, decreasing the density of anchoring points was found to inhibit platelet adhesion to a larger extent and to prolong plasma recalcification time, prothrombin time, thrombin time, and activated partial thromboplastin time to a larger extent. This was also found to enhance the bioactivity of immobilized heparin from 22.9% for raw heparin to 36.9%. This could be explained by the enhanced molecular mobility of immobilized heparin when it is more loosely anchored to the PU surface, as well as a higher surface charge.

scholarly journals Coagulation and Bleeding Disorders: Review and Update

2000 ◽  
Vol 46 (8) ◽  
pp. 1260-1269 ◽  
Author(s):  
Douglas A Triplett
Keyword(s):  
Laboratory Tests ◽  
Platelet Adhesion ◽  
Vascular Wall ◽  
Activated Partial Thromboplastin Time ◽  
Thrombin Time ◽  
Bleeding Disorders ◽  
Coagulation Proteins ◽  
Hereditary Disorders ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Hemostasis is initiated by injury to the vascular wall, leading to the deposition of platelets adhering to components of the subendothelium. Platelet adhesion requires the presence of von Willebrand factor and platelet receptors (IIb/IIIa and Ib/IX). Additional platelets are recruited to the site of injury by release of platelet granular contents, including ADP. The “platelet plug” is stabilized by interaction with fibrinogen. In this review, I consider laboratory tests used to evaluate coagulation, including prothrombin time, activated partial thromboplastin time, thrombin time, and platelet count. I discuss hereditary disorders of platelets and/or coagulation proteins that lead to clinical bleeding as well as acquired disorders, including disseminated intravascular coagulation and acquired circulating anticoagulants.

Blood Coagulation and Fibrinolysis in Haemorrhagic Stroke

1978 ◽  
Vol 39 (01) ◽  
pp. 084-088 ◽  
Author(s):  
Rama Kanta Dube ◽  
P V B Rao ◽  
P K Saha ◽  
B C Katiyar ◽  
B Dube
Keyword(s):  
Platelet Count ◽  
Prothrombin Time ◽  
Fibrinolytic Activity ◽  
Haemorrhagic Stroke ◽  
Factor V ◽  
Thrombin Time ◽  
Clotting Time ◽  
Plasma Recalcification Time ◽  
Recalcification Time ◽  
Coagulation And Fibrinolysis

SummaryStudies of 11 patients with haemorrhagic stroke revealed no significant change in kaolin cephalin clotting time, prothrombin time, thrombin time, PF 3 availability, platelet count and factor V and VIII during the first week. Plasma fibrinogen was significantly increased while factors VII+X were decreased (borderline significance). Prolongation of plasma recalcification time and decrease in heparin tolerance reached borderline significance. There was moderate, but significant, increase in serum antithrombin activity and plasma (euglobulin fraction) fibrinolytic activity.

Generation of a PGI2-Like Activity by Deendothelialized Rat Aorta

1979 ◽  
Vol 42 (03) ◽  
pp. 873-884 ◽  
Author(s):  
Chung-hsin Ts’ao ◽  
Charlotte M Holly ◽  
Margaret A Serieno ◽  
Theresa S Galluzzo
Keyword(s):  
Platelet Adhesion ◽  
Light Transmission ◽  
Rat Aorta ◽  
Activated Partial Thromboplastin Time ◽  
Collagen Fibrils ◽  
Thrombin Time ◽  
Platelet Aggregation Inhibitor ◽  
Inhibitor Activity ◽  
Platelet Factor ◽  
Aggregation Inhibitor

SummaryWe have tested a platelet aggregation inhibitor in the incubation fluid of deendothelialized fragments of the rat aorta and compared it with that of “intact” fragments. Some of the properties of the aortic inhibitor, and its effects on platelet adhesion to collagen fibrils, on platelet factor-3 (PF-3) availability, and on the activated partial thromboplastin time (APTT) and thrombin time (TT) were also evaluated in comparison with similar effects exerted by PGI2. We found that the incubation fluid of deendothelialized aortic samples contained inhibitor activity comparable with that of “intact” samples. The aortic inhibitor had similar properties to PGI2. The aortic inhibitor and PGI2 slightly inhibited light transmission changes of EDTA-PRP following exposure to collagen. However, scanning electron microscopy showed no appreciable difference in platelet adhesion to collagen fibrils. PGI2 and the aortic inhibitor inhibited Kaolin-induced PF-3 availability, but did not prolong the APTT or TT.

Grafting Sulfoammonium Zwitterionic Brushes onto Polycarbonateurethane Surface to Improve Hemocompatibility

2011 ◽  
Vol 306-307 ◽  
pp. 1631-1634 ◽  
Author(s):  
Ya Kai Feng ◽  
Da Zhi Yang ◽  
Hai Yang Zhao ◽  
Jin Tang Guo ◽  
Qing Liang Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Fourier Transform ◽  
Physical Properties ◽  
Water Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Potential Application ◽  
Platelet Adhesion ◽  
Fourier Transform Infrared ◽  
Water Contact ◽  
X Ray

Poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate) (poly(DMAPS)) zwitterionic brushes were grafted onto the polycarbonateurethane (PCU) surface to improve its hydrophilicity and hemocompatibility by Ultraviolet (UV) polymerization. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surface. DMAPS-grafted PCU films showed significantly high hydrophilicity owing to the high hydrophilic poly(DMAPS) zwitterionic brushes. The cytotoxicity tests revealed the sulfoammonium zwitterionic brushes modified PCU film had good cytocompatibility. In addition, the hemocompatibility of the modified PCU films was evaluated by hemolytic tests and platelet adhesion tests. The PCU films modified with zwitterionic brushes had a lower hemolytic index, showed effective resistance to platelet adhesion. Due to the fact that sulfoammonium zwitterionic brushes can improve the hemocompatibility of the PCU surface, this gives rise to its potential application as blood-contacting materials or devices.

Grafting Biomimetic Phospholipid Zwitterionic Brushes onto Polycarbonateurethane for Improving Hemocompatibility

2011 ◽  
Vol 306-307 ◽  
pp. 3-6
Author(s):  
Hai Yang Zhao ◽  
Ya Kai Feng ◽  
Da Zhi Yang ◽  
Jin Tang Guo ◽  
Qing Liang Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Fourier Transform ◽  
Water Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Potential Application ◽  
Platelet Adhesion ◽  
Material Surface ◽  
Adhesion Test ◽  
Water Contact ◽  
X Ray

In order to improve the hemocompatibility of polycarbonateurethane (PCU), the biomimetic phosphorylcholine (PC) group was introduced onto material surface. Brush structure having PC groups was formed by ultraviolet (UV) initiated polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve the hydrophilicity and hemocompatibility of PCU surfaces. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electrical microscopy (SEM) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surfaces. Compared with original PCU, the PC-grafted PCU surfaces showed significantly high hydrophilicity as indicating by low water contact angle. The hemocompatibility of the PC-grafted PCU surfaces was evaluated by platelet adhesion test. The PCU surfaces modified with phosphorylcholine zwitterionic brushes showed effective resistance to platelet adhesion and high hemocompatibility. These PC-grafted PCU materials will have potential application as blood-contacting materials or devices due to their good mechanical and hemocompatible properties.

Heparin Chromatography

1981 ◽  
Author(s):  
R Losito ◽  
H Gattiker ◽  
G Bilodeau ◽  
B Longpré
Keyword(s):  
Gel Electrophoresis ◽  
Systematic Approach ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Weight Fraction ◽  
Activated Partial Thromboplastin Time ◽  
Thrombin Time ◽  
Agarose Gel Electrophoresis ◽  
Recalcification Time ◽  
Second Peak

Commercial heparin is not a homogeneous substance. The isolation of the active component still appears to be a problem and usually requires several different procedures. In order to see if it would be possible to simplify the purification, we studied and compared the chromatography of porcine heparin by a systematic approach using various types of adsorbants, gels and programmed elution techniques employing a Beckman Spectrochrom 130 chromatographic analyzer. A total of 20 combinations were attempted with 200 mg of heparin (169 u/mg) being chromatographed in each case. The fractions of each peak were tested by several methods and included the activated partial thromboplastin time, recalcification time, thrombin time, anti-factor Xa, chromogenic, USP assay, agarose gel electrophoresis and the measurement of metachromatic activity. It was found that dextran gel with an average dry diameter of 75-100 um produced the best chromatograms whose peaks were well resolved. The medium molecular weight fraction of the second peak contained half of the applied heparin. This peak contained all the anticoagulant activity besides reacting very strongly for metachromatic activity. The smaller and larger molecular fractions found in the other three peaks gave very weak metachromatic activity and were devoid of anticoagulant activity. These results have important implications in the preparation and clinical use of heparin.

Evaluation of hemostatic effect of polyelectrolyte complex-based dressings

2017 ◽  
Vol 32 (5) ◽  
pp. 638-647 ◽  
Author(s):  
Manisha Buriuli ◽  
Wasupalli Geeta Kumari ◽  
Devendra Verma
Keyword(s):  
Freeze Drying ◽  
Blood Clotting ◽  
Polyelectrolyte Complex ◽  
Activated Partial Thromboplastin Time ◽  
Polygalacturonic Acid ◽  
Hemostatic Effect ◽  
Chitosan Concentration ◽  
Hemostatic Dressing ◽  
Plasma Recalcification Time ◽  
Recalcification Time

The aim of this work was to develop a polyelectrolyte complex-based hemostatic dressing made from chitosan and polygalacturonic acid. Porous dressings were fabricated by ultrasonication of chitosan and alginate solutions followed by freeze-drying. Since chitosan has inherent hemostatic properties, and polygalacturonic acid is anti-inflammatory in nature, it was desired to combine these two polymers to develop an effective hemostatic dressing, which may also promote wound healing. Porous structure of the bandages was observed using field-emission scanning electron microscope. Blood clotting behavior was studied using whole blood clotting assay. Plasma recalcification time, prothrombin time, and activated partial thromboplastin time were also determined to study the mechanism of clotting. The dressings were found to accelerate clotting rates and showed increased thrombin activity with an increase in chitosan concentration.

Fabrication and Properties of the PVDF/PVDF-g-PMMA Blend Hydrophilic Membrane

2011 ◽  
Vol 418-420 ◽  
pp. 639-642
Author(s):  
Tao Yuan ◽  
Jian Qiang Meng ◽  
Guo Rong Cai ◽  
Yu Feng Zhang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Water Contact ◽  
H Nmr ◽  
Membrane Surfaces ◽  
Static Water

An amphiphilic graft copolymer was obtained via atom transfer radical polymerization (ATRP) of methacrylate (MMA) initiated directly by polyvinylidene fluoride (PVDF). Hydrophilic PVDF membranes were prepared by immersion precipitation of PVDF-g-PMMA and PVDF blend solutions. The chemical structure and the molecular weight were characterized by 1H-NMR and GPC. The hydrophilicity of membrane surfaces were characterized by static water contact angle. Top surface and cross-section of membranes were observed by Field Emission Scanning Electron Microscope (FESEM). The results demonstrated the water contact angle of the membrane surface decreased from 89°to 67°, indicating enhanced hydrophilicity; the pure water flux water firstly decreased and then increased up to 1.7 times of the PVDF membrane. The retention of PEG (Mn=6000) could be maintained at 93%-95%.

scholarly journals The role of contact angle and pore width on pore condensation and freezing

2020 ◽  
Vol 20 (15) ◽  
pp. 9419-9440 ◽  
Author(s):  
Robert O. David ◽  
Jonas Fahrni ◽  
Claudia Marcolli ◽  
Fabian Mahrt ◽  
Dominik Brühwiler ◽  
...  
Keyword(s):  
Contact Angle ◽  
Active Sites ◽  
Water Saturation ◽  
Sol Gel ◽  
Contact Angles ◽  
Ice Nucleation ◽  
Pore Width ◽  
Water Contact ◽  
Pore Condensation

Abstract. It has recently been shown that pore condensation and freezing (PCF) is a mechanism responsible for ice formation under cirrus cloud conditions. PCF is defined as the condensation of liquid water in narrow capillaries below water saturation due to the inverse Kelvin effect, followed by either heterogeneous or homogeneous nucleation depending on the temperature regime and presence of an ice-nucleating active site. By using sol–gel synthesized silica with well-defined pore diameters, morphology and distinct chemical surface-functionalization, the role of the water–silica contact angle and pore width on PCF is investigated. We find that for the pore diameters (2.2–9.2 nm) and water contact angles (15–78∘) covered in this study, our results reveal that the water contact angle plays an important role in predicting the humidity required for pore filling, while the pore diameter determines the ability of pore water to freeze. For T>235 K and below water saturation, pore diameters and water contact angles were not able to predict the freezing ability of the particles, suggesting an absence of active sites; thus ice nucleation did not proceed via a PCF mechanism. Rather, the ice-nucleating ability of the particles depended solely on chemical functionalization. Therefore, parameterizations for the ice-nucleating abilities of particles in cirrus conditions should differ from parameterizations at mixed-phase clouds conditions. Our results support PCF as the atmospherically relevant ice nucleation mechanism below water saturation when porous surfaces are encountered in the troposphere.

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