Synthesis and surface modification studies of biomedical polyurethanes to improve long term biocompatibility

Download

index.pdf

Date

2008

Author

Aksoy, Eda Ayşe

Metadata

Show full item record

Item Usage Stats

287
views

386
downloads

Thrombus formation and blood coagulation is a major problem associated with blood contacting products such as catheters, vascular grafts and artificial hearts. An intense research is being conducted towards the synthesis of new hemocompatible materials and mdifications of surfaces with biological molecules. In this study, polyurethane (PU) films were synthesized in medical purity from diisocyanate and polyol without using any other ingredients and the chemical, thermal and mechanical properties were characterized by solid state NMR, FTIR, GPC, mechanical tests, DMA and TGA. The surfaces of PU films were modified by covalent immobilization of different molecular weight heparins; low molecular weight heparin (LMWH) and unfractionated heparin (UFH) and these surfaces were examined by ESCA, ATR-FTIR, AFM and contact angle goniometer. Cell adhesion studies were conducted with whole human blood and examined by SEM. The effects of different types of heparins on blood protein adsorption and on platelet adhesion were analyzed by electrophresis and SEM, respectively. The surfaces of the UFH immobilized polyurethane films (PU-UFH) resulted in lesser red blood cell adhesion in comparison to LMWH immobilized polyurethane film surfaces (PU-LMWH). When the PU films were treated with blood plasma, the surfaces modified with two different heparin types showed a clearly different protein adsorption behavior especially in the early stage of blood plasma interaction. PU-LMWH samples showed about three times less protein adsorption compared to PU-UFH samples. The morphologies of platelets adhered on material surfaces demonstrated differences; such as PU-UFH had clusters with some pseudopodia extensions, while PU-LMWH had round shaped platelets with little clustering. PU surfaces modified by immobilization of LMWH and UFH, demonstrated promising results for the improvement of non-thrombogenic devices and surfaces.

Subject Keywords

Polymers., Macromolecules.

URI

http://etd.lib.metu.edu.tr/upload/3/12609701/index.pdf
https://hdl.handle.net/11511/17786

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Preparation and characterization of chitosanpolyethylene glycol microspheres and films for biomedical applications Günbaş, İsmail Doğan; Hasırcı, Nesrin; Department of Polymer Science and Technology (2007) In recent years, biodegradable polymeric systems have gained importance for design of surgical devices, artificial organs, drug delivery systems with different routes of administration, carriers of immobilized enzymes and cells, biosensors, ocular inserts, and materials for orthopedic applications. Polysaccharide-based polymers represent a major class of biomaterials, which includes agarose, alginate, dextran, and chitosan. Chitosan has found many biomedical applications, including tissue engineering, owing...
Surface modification of polyurethanes with covalent immobilization of heparin AKSOY, AYŞEGÜL; Hasırcı, Vasıf Nejat; Hasırcı, Nesrin (2007-10-04) Thrombus formation and blood coagulation is a major problem associated with blood contacting products such as catheters, vascular grafts, arteries, artificial hearts and heart valves. An intense research is being conducted towards the synthesis of new hemocompatible materials and modifications of surfaces with biological molecules. In this study, polyurethane (PU) films were synthesized in medical purity from diisocyanate and polyol without using any other ingredients and their surfaces were modified by cov...
Synthesis, characterization, and polymerization of polyether bridged thiophene and aniline derivatives Tirkeş, Seha; Önal, Ahmet Muhtar; Department of Polymer Science and Technology (2008) New compounds consisting of 3-thienyl and aniline units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis and cyclic voltammetry. In the case of 3-thienyl derivatives two compounds, 1,12-di-3-thienyl-2,5,8,11-tetraoxadodecane (MI) and 1,15-di-3-thienyl-2,5,8,11,14-pentaoxapentadecane (MII) were synthesized utilizing literature methods and their corresponding polymers, poly(I) and poly(II) were prepared in an electroly...
Synthesis and characterization of copolymers of diisocyanates and dialcohol Keskin, Selda; Usanmaz, Ali; Department of Polymer Science and Technology (2008) This study was aimed to synthesize low molecular weight hydroxyl terminated polyurethane acrylate polymers that can be used in biomedical applications. Acrylate end capping via inter-esterification reaction was successfully achieved with the methacryloyl chloride addition to the hydroxyl ends of the polyurethane at low temperatures. Isocyanate terminated polyurethane acrylates were also synthesized for the sake of comparison. TDI, HDI and MDI were used as diisocyanates for urethane synthesis and they were e...
Composition-property relationship of PCL based Polyurethanes Güney, Aysun; Hasırcı, Nesrin; Department of Polymer Science and Technology (2012) The desirable properties of polyurethanes (PUs) such as mechanical flexibility associated with chemical versatility make these polymers attractive in the development of biomedical devices. In this study, various segmented polyurethanes were synthesized through polymerization reactions between polycaprolactone (PCL) diol or triol and excess hexamethylene diisocyanate (HDI) with varying NCO/OH ratios and the effect of composition on the properties of the resultant polyurethane films were examined. Initially, ...

Citation Formats

E. A. Aksoy, “Synthesis and surface modification studies of biomedical polyurethanes to improve long term biocompatibility,” Ph.D. - Doctoral Program, Middle East Technical University, 2008.