Heparin immobilization onto segmented polyurethaneurea surfaces—effect of hydrophilic spacers

Парк, Ки Донг; Okano, Teruo; Nojiri, Chisato; Kim, Sung Wan

doi:10.1002/jbm.820221103

Cited by 228 publications

(99 citation statements)

References 13 publications

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“…The calculated amounts of bioactive heparin molecules available at the surface of the coating are a factor of ten lower than found by other investigators [4,5,20]. This is possibly due to the fact that the coating technique traps or buries part of the heparin molecules within the coating matrix, allowing only the detection of heparin at the surface that is actually bioactive.…”

Section: Discussion 41 Estimation Of Surface-boundcontrasting

confidence: 44%

Heparin-containing block copolymers

Vulić

Okano²,

Gaag

et al. 1993

J Mater Sci: Mater Med

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Newly synthesized heparin-containing block copolymers, consisting of a hydrophobic block of polystyrene (PS), a hydrophilic spacer-block of poly(ethylene oxide) (PEO) and covalently bonded heparin (Hep) as bioactive block, were coated either onto glass, poly (dimethylsiioxane), polyurethane or PS substrates. Coated surfaces were characterized by determination of the surface-bound heparin activity, adsorption of AT III, plasma recalcification time assays, adhesion of platelets and by an ex vivo rabbit A-A shunt model.It was demonstrated that heparin was available at the surface of all heparin-bound surfaces to interact with AT III and thrombin and to prevent the formation of clots. The maximum immobilized heparin activity was found to be 5.5 x 10 -3 U cm -2. Coated surfaces showed a significant prolongation of the plasma reclacification times as compared to control surfaces, due to surface-immobilized heparin. The platelet adhesion demonstrated that platelets reacted only minimally with the heparin-containing block copolymers in the test system and that the heparin-containing block copolymers seemed to passify the surface as compared to control surfaces. In the ex vivo A-A shunt experiments, which were carried out under low flow and low shear conditions, the heparin-containing block copolymers exhibited prolonged occlusion times, indicating the ability of the heparin-containing block copolymers to reduce thrombus formation at the surface.

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Section: Discussion 41 Estimation Of Surface-boundcontrasting

confidence: 44%

Heparin-containing block copolymers

Vulić

Okano²,

Gaag

et al. 1993

J Mater Sci: Mater Med

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“…In order to conjugate the Cu(II)-cyclen complex to an existing medical grade hydrophilic thermoplastic PU (Tecophilic®, SP-93A-100), the two key precursors, (Boc) 3 -cyclen-N-acetic acid (1) and aminated PU (2) were prepared by methods analogous to those reported elsewhere [28][29][30] (see Scheme 1). To maintain the strong Cu(II) complexation ability with the cyclen ligand after covalent linkage to the polymer (without any loss of basicity in the cyclen compound), a carboxylic group was introduced on the cyclen moiety via N-alkylation of cyclen using 2-bromoacetic acid and in situ Boc-protection to yield (Boc) 3 -cyclen-N-acetic acid (1).…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Polyurethane with tethered copper(II)–cyclen complex: Preparation, characterization and catalytic generation of nitric oxide from S-nitrosothiols

Hwang

Meyerhoff

2008

Biomaterials

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The preparation and characterization of a commercial biomedical grade polyurethane (Tecophilic, SP-93A-100) material possessing covalently linked copper(II)-cyclen moieties as a nitric oxide (NO) generating polymer are described. Chemiluminescence NO measurements demonstrate that the prepared polymer can decompose endogenous S-nitrosothiols (RSNOs) such as S-nitrosoglutathione and S-nitrosocysteine to NO in the presence of thiol reducing agents (RSHs; e.g., glutathione and cysteine) at physiological pH. Since such RSNO and RSH already exist in blood, the proposed polymer is capable of spontaneously generating NO when in contact with fresh blood. This is demonstrated by utilizing the polymer as an outer coating at the distal end of an amperometric NO sensor to create a device that generates response toward the RSNO species in the blood. This polymer possesses the combined benefits of a commercial biomedical grade polyurethane with the ability to generate biologically active NO when on contact with blood, and thus may serve as a useful coating to improve the hemocompatibility of various medical devices.

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“…Moreover, sulfonate groups were introduced in the SPU to reduce platelet adhesion or protein adsorption [11,12]. Coating of a blood-compatible polymer such as poly(2-hydroxyethyl methacrylate-block-styrene) on the SPU was an effective method to inhibit occlusion even after a 1-year implantation period in dogs [10]. We have investigated the preparation and evaluation of phospholipid polymers as novel biomaterials [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…To prevent this thrombogenicity, many surface modifications studies have been carried out. They included the covalent bonding of alkyl groups for the selective adsorption of albumin [8], poly(ethylene oxide), PEO, chains for the reduction of protein adsorption [9], and heparin molecules for preventing thrombin activation on the surface [10]. Moreover, sulfonate groups were introduced in the SPU to reduce platelet adhesion or protein adsorption [11,12].…”

Section: Introductionmentioning

confidence: 99%

Domain-controlled polymer alloy composed of segmented polyurethane and phospholipid polymer for biomedical applications

Ogawa

Watanabe

Ishihara

2003

Science and Technology of Advanced Materials

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Segmented polyurethane(SPU)s are block polymers which have a good elastic property and thermoplasticity. However, the biocompatibility of SPU is not sufficient, and a living organism rejects the SPU as a foreign material. Thus, some modification is needed to provide excellent biocompatibility and retain the good physical characteristics of the SPUs. In this study, we blended the 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer with SPU to prepare an SPU/MPC polymer alloy. We investigated the effects of the molecular weight ðM w Þ of the MPC polymer on the microdomain structure and mechanical property of the polymer alloy. When the MPC polymer with a higher M w was blended with SPU, the polymer alloy underwent a reduction in mechanical strength. On the other hand, even when the lower M w of the MPC polymer was blended with SPU, differential scanning calorimetric analysis revealed that the MPC polymer chains did not disrupt the crystallinity of the hard segments of SPU and the polymer alloy could maintain its physical properties the same as that of the original SPU. We investigated the adsorption of immunoglobulin (IgG) on the surface of the polymer alloy for evaluation of its fundamental biocompatibility. The SPU/MPC polymer alloy lowered the amount of adsorbed IgG compared to that on SPU. This means that the blending of the MPC polymer significantly improved the biocompatibility of the SPU. We succeeded in preparing an SPU/MPC polymer alloy that possesses both the good mechanical property of SPU and the improved biocompatibility using MPC polymers. q

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Heparin immobilization onto segmented polyurethaneurea surfaces—effect of hydrophilic spacers

Cited by 228 publications

References 13 publications

Heparin-containing block copolymers

Heparin-containing block copolymers

Polyurethane with tethered copper(II)–cyclen complex: Preparation, characterization and catalytic generation of nitric oxide from S-nitrosothiols

Domain-controlled polymer alloy composed of segmented polyurethane and phospholipid polymer for biomedical applications

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