Heart valves, biocompatibility

Coatings for hip j oints, heart valves, and other prostheses DLC is biocompatible and blood compatible,... 

Polymer-based heart valves are widely used as replacements for diseased or damaged human heart valves. Most mechanical heart valves are made from metals, silicone, or polyesters, although some work has gone into incorporating biocompatible coatings such as PEO into these systems. 

EFE is immobilized in a Korean type total artificial heart valve by photoreaction polyallylamine is used as a photoreactive linker [86-88]. The proteolytic activity of the treated valves is three times higher than that of untreated valves using the azocasein method. These data show that an EFE-treated polyurethane valve leads to decreasing thrombus formation in vivo and that their biocompatibility is therefore greater than that of untreated valve. It is expected that EFE could be applied as a novel accessory in the artificial organs implanted into human body. 

Tweden KS, Cameron JD, Razzouk AJ, Homlberg WR and Kelly SJ (1997) Biocompatibility of silver-modified polyester for antimicrobial protection of prosthetic valves. J Heart Valve Dis 6 553-561. Vince DG and Williams DF (1987) Determination of silver in blood and urine by graphite furnace atomic absorption spectroscopy. Analyst 112 1627-1629. 

Silicone matrix systems have good biocompatibility when implanted subcutaneously [18]. Silicone has received FDA approval for many biomedical applications, including breast prostheses and heart-valve prostheses. 

V. Thomas, M. Jayabalan, A new generation of high flex life polyurethane urea for polymer heart valve-studies on in vivo biocompatibility and biodurability, J. Biomed. Mater Res. A 89 (1) (2009) 192-205. 

M. Dabagh, M.J. Abdekhodaie, M.T. Khorasani, Effects of polydimethylsiloxane grafting on the calcification, physical properties, and biocompatibility of polyurethane in a heart valve, J. Appl. Polym. Sci. 98 (2005) 758-766. 

Due to their chemical inertness, high abrasion resistance, low friction and good biocompatibility DLC films are very promising candidates for biomedical applications. For example, femoral heads of hip protheses have been coated successfully with DLC to reduce the production of small wear particles, which can lead to reactions on a cellular level. Furthermore DLC was shown to be a potential material for artificial heart valves where the films must be non-thrombogenic and must have a long-time stabihty in contact with blood [93]. Mitura et al. [94] investigated DLC... 

The surface of any material governs its interactions with the environment. Knowledge over and control of these interaction is especially important when a material is in contact with the biosystem, for example, when applied as transplant, in tissue engineering, in cell cultures, and in blood contact, as weU as in biosensors in medicinal diagnosis, fluids analysis, environmental moititoring, and many other areas. Whereas, on the one hand, the bulk properties of the material are essential for its successful application, for example, as a catheter or a heart valve, special attention has to be paid to render to the surface suitable biocompatible or bioactive properties, no matter of the chemical composition of the bulk material. This is usually achieved by any surface modification process by low molar mass or polymeric compounds. An essential feature of such a modification procedure is the need for a permanent and bioresistant surface finish [87]. 

Medical implants used in orthopedic surgery and heart valves are made of titanium and stainless steel alloys, primarily because they are biocompatible and help the patient to lead a normal life. Unfortunately, in some cases these metal alloys may... 

PVA cryogel (PVA-C) has caught the interest of researchers in the biomedical field since its creation in the early 1980s [43], Apart from its long-term biocompatibility and nontoxicity [44], its mechanical properties, which can be tailored to mimic a wide range of soft tissues [7, 45], are the main reason why PVA-C is an attractive candidate material for many prosthetic devices such as heart valves, blood vessels, and articular cartilages. 

Characteristics high flexibility and high impact resistance, and excellent biocompatibility. Film forms of polyurethane have been used in fabrication of vascular graft and patches, heart valve leaflets, blood pumps, diaphragms for implantable artificial heart, and carriers for drug delivery. Elastomeric fibers (Spandex) made from polyurethane copolymer have been used in surgical hoses. 

Schoen, F.J. (1983) Carbons in heart valve prostheses Foundations and clinical performance, in M. Szycher (ed.). Biocompatible Polymers, Metals, and Composites, Technomic Publishing Co., Lancaster, Pennsylvania, pp. 239-61. 

Whenever a biotextile device is used in a different appUcation or is implanted at a different site, or apphed to a different patient population, its performance needs to be evaluated in terms of its biocompatibility, biofunctionality and biostabiUty using a different or spedalized test protocol or procedure. For example, when using a biotextile structure as a heart valve leaflet it is important to study the propensity for calcification and to evaluate the effectiveness of any preventive measures that limit the extent of caldfication. Alternatively, the study of breast implants, sutures and hernia repair meshes each require some specific tests which are described in this section. 

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