Blood compatibility and permeability of heparin-modified polysulfone as potential membrane for simultaneous hemodialysis and LDL removal

Facile Preparation of β-Cyclodextrin-Modified Polysulfone Membrane for Low-Density Lipoprotein Adsorption via Dopamine Self-Assembly and Schiff Base Reaction

A facile method for the immobilization of β-cyclodextrin on polysulfone membranes with the aim of selectively adsorbing low-density lipoprotein (LDL) was established, which is based on the self-assembly of dopamine on the membrane followed by the Schiff base reaction with mono-(6-ethanediamine-6-deoxy)-β-cyclodextrin. The surface modification processes were validated using X-ray photoelectron spectroscopy and attenuated total reflectance Fourier-transform infrared spectroscopy. Surface wettability and surface charge of the membranes were investigated through the water contact angle and zeta potential analysis. The cyclodextrin-modified polysulfone membrane (PSF-CD) showed good resistance to protein solutions, as shown by the measurement of BSA adsorption. The assessment of BSA adsorption revealed that the cyclodextrin-modified polysulfone membrane (PSF-CD) exhibited excellent resistance to protein solutions. To investigate the adsorption and desorption behaviors of the membranes in single-protein or binary-protein solutions, an enzyme-linked immunosorbent assay was employed. The results revealed that the PSF-CD possessed remarkable adsorption capacity and higher affinity for LDL in both single-protein and binary-protein solutions, rendering it a suitable material for LDL apheresis.

Unravelling Surface Modification Strategies for Preventing Medical Device-Induced Thrombosis

The use of biomaterials in implanted medical devices remains hampered by platelet adhesion and blood coagulation. Thrombus formation is a prevalent cause of failure of these blood-contacting devices. Although systemic anticoagulant can be used to support materials and devices with poor blood compatibility, its negative effects such as an increased chance of bleeding, make materials with superior hemocompatibility extremely attractive, especially for long-term applications. This review examines blood-surface interactions, the pathogenesis of clotting on blood-contacting medical devices, popular surface modification techniques, mechanisms of action of anticoagulant coatings, and discusses future directions in biomaterial research for preventing thrombosis. In addition, this paper comprehensively reviews several novel methods that either entirely prevent interaction between material surfaces and blood components or regulate the reaction of the coagulation cascade, thrombocytes, and leukocytes.

High flux novel polymeric membrane for renal applications

Biocompatibility and the ability to mediate the appropriate flux of ions, urea, and uremic toxins between blood and dialysate components are key parameters for membranes used in dialysis. Oxone-mediated TEMPO-oxidized cellulose nanomaterials have been demonstrated to be excellent additives in the production and tunability of ultrafiltration and dialysis membranes. In the present study, nanocellulose ionic liquid membranes (NC-ILMs) were tested in vitro and ex vivo. An increase in flux of up to two orders of magnitude was observed with increased rejection (about 99.6%) of key proteins compared to that of polysulfone (PSf) and other commercial membranes. NC-ILMs have a sharper molecular weight cut-off than other phase inversion polymeric membranes, allowing for high throughput of urea and a uremic toxin surrogate and limited passage of proteins in dialysis applications. Superior anti-fouling properties were also observed for the NC-ILMs, including a > 5-h operation time with no systemic anticoagulation in blood samples. Finally, NC-ILMs were found to be biocompatible in rat ultrafiltration and dialysis experiments, indicating their potential clinical utility in dialysis and other blood filtration applications. These superior properties may allow for a new class of membranes for use in a wide variety of industrial applications, including the treatment of patients suffering from renal disease.

Fabrication and Study of Dextran/Sulfonated Polysulfone Blend Membranes for Low-Density Lipoprotein Adsorption

The abnormal increase in low-density lipoprotein (LDL) in human blood is a main independent risk factor for the pathogenesis of atherosclerosis, whereas a reduced LDL level effectively lowers morbidity. It is important to develop LDL adsorption materials with high efficiency and selectivity, as well as to simplify their fabrication processes. In this paper, polysulfone (PSF), sulfonated polysulfone (SPSF), and sulfonated polysulfone/dextran (SPSF/GLU) membranes were successfully fabricated for LDL adsorption using a solution casting technique. Attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements confirmed the success of the preparation. The water contact angle decreased from 89.7 ± 3.4° (PSF) to 76.4 ± 3.2° (SPSF) and to 71.2 ± 1.9° (SPSF/GLU), respectively. BSA adsorption testing showed that the SPSF/GLU with surface enrichment of sulfonate groups and glycosyl groups possessed higher resistance to protein solution. The adsorption and desorption behaviors of the studied samples in single-protein or binary-protein solutions were systematically investigated by enzyme-linked immunosorbent assay (ELISA), The results showed that SPSF/GLU, which had excellent resistance to protein adsorption, possessed a similar adsorption capacity to that of PSF. SPSF membrane exhibited excellent selective affinity for LDL in single and binary protein solutions, suggesting potential applications in LDL removal.

Recent advancement challenges with synthesis of biocompatible hemodialysis membranes

The focus of this study is to enhance the protein fouling resistance, hydrophilicity, biocompatibility, hemocompatibility and ability of the membranes and to reduce health complications like chronic pulmonary disease, peripheral vascular disease, cerebrovascular disease, and cardiovascular disease after dialysis, which are the great challenges in HD applications. In the current study, the PSF-based dialysis membranes are studied broadly. Significant consideration has also been provided to membrane characteristics (e.g., flowrate coefficient, solute clearance characteristic) and also on commercially available polysulfone HD membranes. PSF has gained a significant share in the development of HD membranes, and continuous improvements are being made in the process to make high flux PSF-based dialysis membranes with enhanced biocompatibility and improved protein resistance ability as the major issue in the development of membranes for HD application is biocompatibility. There has been a great increase in the demand for novel biocompatible membranes that offer the best performances during HD therapy, for example, low oxidative stress and low change ability of blood pressure.

Functionalized Hemodialysis Polysulfone Membranes with Improved Hemocompatibility

The field of membrane materials is one of the most dynamic due to the continuously changing requirements regarding the selectivity and the upgradation of the materials developed with the constantly changing needs. Two membrane processes are essential at present, not for development, but for everyday life—desalination and hemodialysis. Hemodialysis has preserved life and increased life expectancy over the past 60–70 years for tens of millions of people with chronic kidney dysfunction. In addition to the challenges related to the efficiency and separative properties of the membranes, the biggest challenge remained and still remains the assurance of hemocompatibility—not affecting the blood during its recirculation outside the body for 4 h once every two days. This review presents the latest research carried out in the field of functionalization of polysulfone membranes (the most used polymer in the preparation of membranes for hemodialysis) with the purpose of increasing the hemocompatibility and efficiency of the separation process itself with a decreasing impact on the body.

Anti-Biofouling Polymers with Special Surface Wettability for Biomedical Applications

The use of anti-biofouling polymers has widespread potential for counteracting marine, medical, and industrial biofouling. The anti-biofouling action is usually related to the degree of surface wettability. This review is focusing on anti-biofouling polymers with special surface wettability, and it will provide a new perspective to promote the development of anti-biofouling polymers for biomedical applications. Firstly, current anti-biofouling strategies are discussed followed by a comprehensive review of anti-biofouling polymers with specific types of surface wettability, including superhydrophilicity, hydrophilicity, and hydrophobicity. We then summarize the applications of anti-biofouling polymers with specific surface wettability in typical biomedical fields both in vivo and in vitro, such as cardiology, ophthalmology, and nephrology. Finally, the challenges and directions of the development of anti-biofouling polymers with special surface wettability are discussed. It is helpful for future researchers to choose suitable anti-biofouling polymers with special surface wettability for specific biomedical applications.

Control of Blood Coagulation by Hemocompatible Material Surfaces-A Review

Hemocompatibility of biomaterials in contact with the blood of patients is a prerequisite for the short- and long-term applications of medical devices such as cardiovascular stents, artificial heart valves, ventricular assist devices, catheters, blood linings and extracorporeal devices such as artificial kidneys (hemodialysis), extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass. Although lower blood compatibility of materials and devices can be handled with systemic anticoagulation, its side effects, such as an increased bleeding risk, make materials that have a better hemocompatibility highly desirable, particularly in long-term applications. This review provides a short overview on the basic mechanisms of blood coagulation including plasmatic coagulation and blood platelets, as well as the activation of the complement system. Furthermore, a survey on concepts for tailoring the blood response of biomaterials to improve the hemocompatibility of medical devices is given which covers different approaches that either inhibit interaction of material surfaces with blood components completely or control the response of the coagulation system, blood platelets and leukocytes.

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

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 1H 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.

A review on surface modification methods of poly(arylsulfone) membranes for biomedical applications

Considerable methods have so far been used for the surface modification of biomedical membranes. Several reviews and articles have been published on the improvements achieved in the field of poly(arylsulfone) membranes subjected to various surface modification methods and used in biomedical applications. This review concentrates on the surface modification, biological applications and future perspective of the poly(arylsulfone) biomedical membranes. Different surface modification procedures employed for the poly(arylsulfone) membranes have been classified, studied and compared. Diverse surface modification techniques include surface coating, chemical modification and immobilization/cross-linking, grafting, surface zwitterionicalization, mussel-inspired coating and layer-by-layer assembly. Furthermore, we review the recent research studies performed on the surface modification of the poly(arylsulfone) biomedical membranes. Meanwhile, the properties of biomedical membranes are also discussed in each section. At last, the future perspective and challenges of the strategies utilized for the surface modification of poly(arylsulfone) biomedical membranes are presented.

Arteriovenous access in hemodialysis: A multidisciplinary perspective for future solutions

In hemodialysis, vascular access is a key issue. The preferred access is an arteriovenous fistula on the non-dominant lower arm. If the natural vessels are insufficient for such access, the insertion of a synthetic vascular graft between artery and vein is an option to construct an arteriovenous shunt for punctures. In emergency situations and especially in elderly with narrow and atherosclerotic vessels, a cuffed double-lumen catheter is placed in a larger vein for chronic use. The latter option constitutes a greater risk for infections while arteriovenous fistula and arteriovenous shunt can fail due to stenosis, thrombosis, or infections. This review will recapitulate the vast and interdisciplinary scenario that characterizes hemodialysis vascular access creation and function, since adequate access management must be based on knowledge of the state of the art and on future perspectives. We also discuss recent developments to improve arteriovenous fistula creation and patency, the blood compatibility of arteriovenous shunt, needs to avoid infections, and potential development of tissue engineering applications in hemodialysis vascular access. The ultimate goal is to spread more knowledge in a critical area of medicine that is importantly affecting medical costs of renal replacement therapies and patients’ quality of life.

Wetting properties of blood lipid fractions on different titanium surfaces

Background

Blood is the first tissue contacting the implant surface and starting the biological interactions to enhance osseointegration and stimulate bone formation with the progenitor cytokines, chemokines, and growth factors. The coagulation cascade initiates the first step of osseointegration between implant and neighboring tissues. The wound healing may be inadequate unless the blood wets the implant surface properly. Wettability is one of the most important features of the implant surface while lipid level constitutes a milestone that may change the energy of blood, which determines its distribution on implant material. Thus, the aim of this study was to evaluate the effect of lipid component of blood as cholesterol and its treatment on their wetting behavior of titanium surfaces.

Methods

Five surface groups were formed including grade 4 titanium-machined, grade 4 titanium-SLA, grade 4 titanium-SLActive, Roxolid-SLA, and Roxolid-SLActive. In healthy, hyperlipidemic, and treatment situations, blood was taken from eight rabbits and dropped to the disc surfaces. Contact angles were measured between the blood samples and disc surfaces.

Results

A significant difference was found between both machined and SLActive surfaces, SLA and SLActive surfaces in the hyperlipidemic period, and only Roxolid-SLA and SLActive surfaces during the treatment period. When evaluated according to time, only grade 4-machined and Grade 4-SLA surfaces showed a significant difference.

Conclusions

Our findings indicated that each period has its own characteristics and showed the importance of cholesterol in blood structure on applicability of implant surfaces.

Preparation and performance of poly(4-vinylpyridine)-b-polysulfone-b-poly(4-vinylpyridine) triblock copolymer/polysulfone blend membrane for separation of palladium (II) from electroplating wastewaters

In order to separate palladium (II) from electroplating wastewaters, poly(4-vinylpyridine)-b-polysulfone-b-poly(4-vinylpyridine) (P4VP-PSF-P4VP) / polysulfone blend membranes were fabricated by combining non-solvent induced phase separation, surface segregation and self-assembly of block copolymer. Amphiphilic P4VP-PSF-P4VP was used as the membrane base material, which was synthesized by introducing the functional monomer of 4-vinylpyridine (4-VP), and polysulfone as the additive. Effects of blend ratio and 4-VP content on membrane performance, such as structure, hydrophilicity, pure water flux and adsorption capacity towards Pd (II), were investigated. The membranes exhibited dense surface structure and low roughness due to surface segregation and self-assembly of P4VP-PSF-P4VP. The presence of 4-VP increased hydrophilicity and water flux of membrane, and it also provided good adsorption capacity towards Pd (II) (up to 103.1 ± 5.15 mg/g). Further, the membrane was used to separate Pd (II) from simulated wastewaters during filtration. It showed good rejection ability and high selectivity towards Pd (II) in co-existence of Cu (II) and Ni (II), and selectivity coefficients of Pd/Cu and Pd/Ni are 41.9 ± 1.88 and 97.8 ± 4.32, respectively. In filtration process of actual electroplating wastewater, the membrane also exhibited excellent rejection performance (Pd (II) rejection reached up to 96.8 ± 2.71%). Perhaps it is suitable for future practice applications.

Development of functionalized polyetherimide/polyvinylpyrrolidone membranes for application in hemodialysis

The present study aimed to synthesize membranes for hemodialysis based on polyetherimide (PEI) and polyvinylpyrrolidone (PVP), with chemical immobilization of heparin on its surface to increase blood compatibility. The synthesized PEI/PVP membranes were characterized by morphological analysis and transport properties, as well by infrared spectroscopy (FT-IR), protein adsorption, contact angle, activated partial thromboplastin time (aPTT), and platelet adhesion. Hydraulic permeability of the synthesized PEI membranes were comparable to those of current high flux clinical membranes; values of diffusive permeability and rejection for typical solutes were similar to those reported in literature. The immobilization of heparin, in turn, resulted in more hydrophilic membranes, with insignificant protein adsorption and platelet adhesion (as opposed to actual clinical membranes), indicating anti-thrombogenic characteristics as confirmed by increased aPTT.

Effect of thiolated glycosaminoglycans on the behavior of breast cancer cells: toward the development of in vitro models of cancer

PURPOSE

The influence of extracellular matrix components like glycosaminoglycans (GAG) or adhesive proteins on the migration of cancer cells and the progression of tumorigenesis remains a challenging task. Therefore, this study aims to give insight into the interaction of cancer cells exhibiting different metastatic potential (MDA-MB-231, MDA-MB-468) with surface immobilized GAG interacting with serum proteins like fibronectin.

METHODS

Model substrata were covalently coated with different thiolated GAG (hyaluronan (HA), chondroitin sulfate (CS), heparin (Hep)) and investigated for the adsorption of fibronectin (FN) with surface plasmon resonance. Then, adhesion of breast cancer cells in the presence of and without serum proteins was studied. Further, the outgrow behavior of confluent cancer cells was examined with the help of cell migration chambers and single-cell migration with time-lapse microscopy.

RESULTS

FN adsorption revealed that the Hep-coated surfaces were able to adsorb significantly more protein than CS and HA. Generally, initial adhesion of breast cancer cells on GAG-coated substrata was inhibited for HA- and CS-coated substrata in the presence of serum proteins for both cell lines in comparison to serum-free conditions. The cell size was also significantly decreased by the influence of serum proteins. The outgrow studies clearly confirmed the different migration speed of both cancer cells while single-cell migration was particularly enhanced on HA-coated surfaces.

CONCLUSIONS

The results reveal that adsorption of serum proteins (e.g. albumin) possess an inhibiting effect on the adhesion of breast cancer cells and that single-cell migration is enhanced for both breast cancer cell lines on HA.

Anionic glycosylated polysulfone membranes for the affinity adsorption of low-density lipoprotein via click reactions

An anionic glycosylated polysulfone (PSf) membrane was prepared as a high-affinity adsorbent for low-density lipoprotein (LDL). The UV-induced grafting of acrylic acid to the membrane was followed by amidation and a 'thiol-yne' click reaction to achieve glycosylation and sulfonation. Membrane modification was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. These tests revealed that the chemical compositions of the membranes' surfaces were easily regulated by controlling the 'thiol-yne' click reaction through the feed ratio of 2,3,4,6-tetra-O-acetyl-1-thio-β-d-glucopyranose and sodium 3-mercapto-1-propanesulfonate. LDL adsorption and desorption rates were estimated using an enzyme-linked-immunosorbent assay, which revealed that the obtained anionic glycosylated PSf membrane had a higher affinity for LDL than either glycosylated or sulfonated membranes alone. The combination of glycosyl and sulfonyl groups enhanced the membranes' affinities for LDL. The modified PSf membrane had an excellent biocompatibility and adsorbed a large amount of LDL, making it a promising material for LDL apheresis.

STATEMENT OF SIGNIFICANCE

Low-density lipoprotein (LDL) adsorbents normally contain negative charged ligand to induce electrostatic interaction with the positively charged regions of LDL. Furthermore, saccharide is another common component which share in most of the LDL-adsorbents and the LDL-receptor (LDLR). Such structural similarity impels us to investigate the synergistic effect of anionic and saccharide on LDL recognition. For this purpose, an anionic glycosylated membrane of which surface composition can be controlled by click reaction with mutable glycosyl/sulfonyl ratios was prepared. The obtained membrane showed better LDL adsorption/desorption property and the adsorption amount for LDL at an optimum feed ratio. This finding highlights the role of synergistic effect of anionic and saccharide, which offer a new strategy for designing LDL adsorbent with high efficiency.

Hemocompatibility and oxygenation performance of polysulfone membranes grafted with polyethylene glycol and heparin by plasma-induced surface modification

Polyethylene glycol (PEG) and heparin (Hep) were grafted onto polysulfone (PSF) membrane by plasma-induced surface modification to prepare PSF-PEG-Hep membranes used for artificial lung. The effects of plasma treatment parameters, including power, gas type, gas flow rate, and treatment time, were investigated, and different PEG chains were bonded covalently onto the surface in the postplasma grafting process. Membrane surfaces were characterized by water contact angle, PEG grafting degree, attenuated total reflectance-Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, X-ray photoelectron spectroscopy, critical water permeability pressure, and scanning electron microscopy. Protein adsorption, platelet adhesion, and coagulation tests showed significant improvement in the hemocompatibility of PSF-PEG-Hep membranes compared to pristine PSF membrane. Gas exchange tests through PSF-PEG6000-Hep membrane showed that when the flow rate of porcine blood reached 5.0 L/min, the permeation fluxes of O₂ and CO₂ reached 192.6 and 166.9 mL/min, respectively, which were close to the gas exchange capacity of a commercial membrane oxygenator. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1737-1746, 2017.

Functionalized MWCNTs in improving the performance and biocompatibility of potential hemodialysis membranes

Functionalized multi-walled carbon nanotube incorporated polyetherimide mixed matrix membranes for blood purification application.

Constructing Functional Ionic Membrane Surface by Electrochemically Mediated Atom Transfer Radical Polymerization

The sodium polyacrylate (PAANa) contained polyethersulfone membrane that was fabricated by preparation of PES-NH2via nonsolvent phase separation method, the introduction of bromine groups as active sites by graftingα-Bromoisobutyryl bromide, and surface-initiated electrochemically atom transfer radical polymerization (SI-eATRP) of sodium acrylate (AANa) on the surface of PES membrane. The polymerization could be controlled by reaction condition, such as monomer concentration, electric potential, polymerization time, and modifier concentration. The membrane surface was uniform when the monomer concentration was 0.9 mol/L, the electric potential was −0.12 V, the polymerization time was 8 h, and the modifier concentration was 2 wt.%. The membrane showed excellent hydrophilicity and blood compatibility. The water contact angle decreased from 84° to 68° and activated partial thromboplastin increased from 51 s to 84 s after modification of the membranes.

Interfacial Self-Assembly of Heparin-Mimetic Multilayer on Membrane Substrate as Effective Antithrombotic, Endothelialization, and Antibacterial Coating

In this study, we design the interfacial self-assembly of heparin-mimetic multilayer on poly(ether sulfone) (PES) membrane, which can endow the substrate with excellent cytocompatibility, highly hemocompatibility and enhanced antibacterial properties. The coated 3D sponge-like multilayer was fabricated by surface engineered layer by layer assembly of sulfonic amino polyether sulfone (SNPES) and quaternized chitosan (QC). The cell morphology observation and viability evaluation suggested that the assembled multilayer coating had remarkable cytocompatibility with endothelial cells due to the synergistic promotion of bovine serum albumin adsorption and heparin-mimetic groups; which further indicated that surface endothelialization could be achieved on the heparin-mimetic multilayer. The systematical tests of antithrombotic and blood activation indicated that the heparin-mimetic multilayer-coated membrane owned significantly suppressed adsorption of bovine serum fibrinogen, platelet adhesion and activation, prolonged clotting times, as well as lower activation of blood complement. Furthermore, the antibacterial test suggested the multilayer coated substrates exhibited obvious inhibition capability for both Escherichia coli and Staphylococcus aureus. Therefore, we believe that the developed SNPES/QC multilayer on PES membrane show great potential as a multifunctional coating toward versatile biomedical applications due to the integrated and highly effective antithrombotic, endothelialization, and antibacterial properties.

Surface modification of silk fibroin fabric using layer-by-layer polyelectrolyte deposition and heparin immobilization for small-diameter vascular prostheses

There is an urgent need to develop a biologically active implantable small-diameter vascular prosthesis with long-term patency. Silk-fibroin-based small-diameter vascular prosthesis is a promising candidate having higher patency rate; however, the surface modification is indeed required to improve its further hemocompatibility. In this study, silk fibroin fabric was modified by a two-stage process. First, the surface of silk fibroin fabric was coated using a layer-by-layer polyelectrolyte deposition technique by stepwise dipping the silk fibroin fabric into a solution of cationic poly(allylamine hydrochloride) (PAH) and anionic poly(acrylic acid) (PAA) solution. The dipping procedure was repeated to obtain the PAH/PAA multilayers deposited on the silk fibroin fabrics. Second, the polyelectrolyte-deposited silk fibroin fabrics were treated in EDC/NHS-activated low-molecular-weight heparin (LMWH) solution at 4 °C for 24 h, resulting in immobilization of LMWH on the silk fibroin fabrics surface. Scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray data revealed the accomplishment of LMWH immobilization on the polyelectrolyte-deposited silk fibroin fabric surface. The higher the number of PAH/PAA coating layers on the silk fibroin fabric, the more surface hydrophilicity could be obtained, resulting in a higher fetal bovine serum protein and platelets adhesion resistance properties when tested in vitro. In addition, compared with untreated sample, the surface-modified silk fibroin fabrics showed negligible loss of bursting strength and thus reveal the acceptability of polyelectrolytes deposition and heparin immobilization approach for silk-fibroin-based small-diameter vascular prostheses modification.

Construction of d-α-tocopheryl polyethylene glycol succinate/PEO core–shell nanofibers on a blood-contacting surface to reduce the hemolysis of preserved erythrocytes

The TPGS released from the electrospun SEBS protected the preserved red blood cells from oxidative damage, resulting in low hemolysis and mechanical fragility.

Polydopamine-assisted deposition of heparin for selective adsorption of low-density lipoprotein

Low-density lipoprotein (LDL) is the main carrier of blood cholesterol, with elevated levels of LDL increasing the risk of atherosclerosis.

Robust poly(lactic acid) membranes improved by polysulfone-g-poly(lactic acid) copolymers for hemodialysis

A novel brush-like copolymer was synthesized to toughen and modify PLA membrane. Modified PLA membrane showed improved mechanical, thermal and filtration performances.

Surface modification of poly(ether sulfone) membrane with a synthesized negatively charged copolymer

In this study, we provide a new method to modify poly(ether sulfone) (PES) membrane with good biocompatibility, for which diazotized PES (PES-N2(+)) membrane is covalently coated by a negatively charged copolymer of sodium sulfonated poly(styrene-alt-maleic anhydride) (NaSPS-MA). First, aminated PES (PES-NH2) is synthesized by nitro reduction reaction of nitro-PES (PES-NO2), and then blends with pristine PES to prepare PES/PES-NH2 membrane; then the membrane is treated with NaNO2 aqueous solution at acid condition; after surface diazo reaction, surface positively charged PES/PES-N2(+) membrane is prepared. Second, poly(styrene-alt-maleic anhydride) (PS-alt-MA) is synthesized, then sulfonated and treated by sodium hydroxide solution to obtain sodium sulfonated (PS-alt-MA) (NaSPS-MA). Finally, the negatively charged NaSPS-MA copolymer is coated onto the surface positively charged PES/PES-N2(+) membrane via electrostatic interaction; after UV-cross-linking, the linkage between the PES-N2(+) and NaSPS-MA changes to a covalent bond. The surface-modified PES membrane is characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS) analyses, and surface zeta potential analyses. The modified membrane exhibits good hemocompatibility and cytocompatibility, and the improved biocompatibility might have resulted from the existence of the hydrophilic groups (sodium carboxylate (-COONa) and sodium sulfonate (-SO3Na)). Moreover, the stability of the modified membrane is also investigated. The results indicated that the modified PES membrane using negatively charged copolymers had a lot of potential in blood purification fields and bioartificial liver supports for a long time.

Development and hemocompatibility testing of nitric oxide releasing polymers using a rabbit model of thrombogenicity

Hemocompatibility is the goal for any biomaterial contained in extracorporeal life supporting medical devices. The hallmarks for hemocompatibility include nonthrombogenicity, platelet preservation, and maintained platelet function. Both in vitro and in vivo assays testing for compatibility of the blood/biomaterial interface have been used over the last several decades to ascertain if the biomaterial used in medical tubing and devices will require systemic anticoagulation for viability. Over the last 50 years systemic anticoagulation with heparin has been the gold standard in maintaining effective extracorporeal life supporting. However, the biomaterial that maintains effective ECLS without the use of any systemic anticoagulant has remained elusive. In this review, the in vivo 4-h rabbit thrombogenicity model genesis will be described with emphasis on biomaterials that may require no systemic anticoagulation for extracorporeal life supporting longevity. These novel biomaterials may improve extracorporeal circulation hemocompatibility by preserving near resting physiology of the major blood components, the platelets and monocytes. The rabbit extracorporeal circulation model provides a complete assessment of biomaterial interactions with the intrinsic coagulation players, the circulating platelet and monocytes. This total picture of blood/biomaterial interaction suggests that this rabbit thrombogenicity model could provide a standardization for biomaterial hemocompatibility testing.

Immobilization of sodium alginate sulfates on polysulfone ultrafiltration membranes for selective adsorption of low-density lipoprotein

A novel method for the immobilization of sodium alginate sulfates (SAS) on polysulfone (PSu) ultrafiltration membranes to achieve selective adsorption of low-density lipoprotein (LDL) was developed, which involved the photoinduced graft polymerization of acrylamide on the membrane and the Hofmann rearrangement reaction of grafted acrylamide followed by chemical binding of SAS with glutaraldehyde. The surface modification processes were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterization. Zeta potential and water contact angle measurements were performed to investigate the surface charge and wettability of the membranes. An enzyme-linked immunosorbent assay was used to measure the binding of LDL on plain and modified PSu membranes. It was found that the PSu membrane immobilized with sodium alginate sulfates (PSu-SAS) greatly enhanced the selective adsorption of LDL from protein solutions and the absorbed LDL could be easily eluted with sodium chloride solution, indicating a specific and reversible binding of LDL to SAS, mainly driven by electrostatic forces. Furthermore, the PSu-SAS membrane showed good blood compatibility as examined by platelet adhesion. The results suggest that the PSu-SAS membranes are promising for application in simultaneous hemodialysis and LDL apheresis therapy.