Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells

Abstract

Polyurethane copolymers based on α,ω-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.

Influence of the Organoclay Content on the Structure, Morphology, and Surface Related Properties of Novel Poly(dimethylsiloxane)-Based Polyurethane/Organoclay Nanocomposites

“…°C for 24 h. Solvent residue was evaporated by drying to constant mass (conditions were vacuum oven (0.5 mmHg), 60 o C, 24 h) as previously described. 25,35 Finally, films of the polymerized materials, approximately 0.2 mm thick, were recovered from their Teflon molds and saved for analysis.…”

“…30 We previously studied the fabrication of PDMS-based TPUs as well as their characterization and biocompatibility assessment, and confirmed that the chemical structure and amounts of the soft PDMS segments have a predominant influence on the surface, thermal, thermomechanical and biocompatible characteristics of PDMS-based TPUs. [32][33][34][35][36] We have found that good hemoand cyto-compatibility is related to higher surface roughness, better microphase separation structure, and higher hydrophilicity of these TPUs.…”

Synthesis and structure-property relationships of biodegradable polyurethanes

“…The synthesis of PU copolymers using siloxane-containing prepolymers with PCL and ethylene oxide terminal units has been described [90][91][92][93][94][95][96][97][98]; these terminal units of siloxane-containing prepolymers were used in order to increase the miscibility of polar and non-polar reactants. Thermoplastic PU elastomers based on PDMS were synthesized by a two-step polyaddition procedure in solution, from MDI, 1,4-BD and α,ω-dihydroxy-PCL-b-PDMS-b-PCL [94].…”

“…Potentially biocompatible thermoplastic PUS and PUUS copolymers based on α,ω-dihydroxypropyl-PDMS with different soft segment content have been prepared and characterized [30,97,99]. In these copolymers, the crystallinity, moduli, hydrophilicity, surface free energy and surface roughness increased with decreasing PDMS content.…”

Blended Polyurethane and Tropoelastin as a Novel Class of Biologically Interactive Elastomer

“…7 Elast-Eon is used as a long-term implantable material for cardiovascular applications such as replacement grafts, components of blood pumps, stent coatings, catheters, and orthopedic implants. 8 However, it is inherently incapable of modulating the interactions of cells, including fibroblasts, and, as a consequence, promotes an elevated in vivo fibrotic response that limits its use in tissue repair. 9 A useful approach to improve the biological interaction of synthetic polymers has been to blend them with natural materials.…”