Biocompatibility elastomeric materials

In a design approach unique among gecko-inspired adhesives, hiodegradable dextran-coated poly(glycerol-co-sebacate acrylate) has been used to create patterned arrays of microscale truncated cones, and used to improve attachment of adhesive tapes to tissue surfaces. While this biocompatible, elastomeric material is not intended for reversible adhesion and... 

Misra, G. R Amsden, B. G. Biodegradable/biocompatible elastomeric materials for use as implantable drug delivery devices. Can. Pat. Appl. CA 2504076, 2006 Chem. Abstr. 2006,145, 425998. 

Starting with the silicone elastomer hydrocephalus shunt in 1955, silicone elastomer has become widely used as a soft, flexible, elastomeric material of construction for artificial organs and implants for the human body. When prepared with controls to assure its duplication and freedom from contamination, specific formulations have excellent biocompatibility, biodurability, and a long history of clinical safety. Properties can be varied to meet the needs in many different implant applications. Silicone elastomer can be fabricated in a wide variety of forms and shapes by most all of the techniques used to fabricate thermosetting elastomers. Radiopacity can be increased by fillers such as barium sulfate or powdered metals. It can be sterilized by ethylene oxide, steam autoclave, dry heat, or radiation. Shelf-life at ambient conditions is indefinite. When implanted the host reaction is typically limited to encapsulation of... 

Artificial organs and implants to replace diseased, defective, or destroyed components of the body are used by essentially every medical specialty. Medical grade silicone elastomer is the only elastomer generally recognized as safe and effective as a material of construction for soft, flexible, elastomeric implants. Carefully controlled formulations have been qualified by chronic biocompatibility and biodurability studies to provide a soft, flexible, elastomeric material of construction to meet many of the needs in these applications. 

PHAs can be either thermoplastic or elastomeric materials with variable mechanical, thermal stability and durability properties. They are water insoluble and impermeable to oxygen [14]. Due to the stereospecificity of the PHA synthase, all the hydroxyalkanoate monomers incorporated in the polymer are in the R(—) configuration, resulting in an optically pure polymer [15]. Additionally, they are biodegradable hence, they can be degraded and metabolized by microbes and by enzymes within the human body biocompatible, they do not generate toxic byproducts and some of them are piezoelectric, a property known to stimulate cell growth [4]. 

Briganti, E., Lost, R, Raffl, A., Scoccianti, M., Munao, A., Soldani, G., 2006. Silicone based polyurethane materials a promising biocompatible elastomeric formulation for cardiovascular applications. Journal of Materials Science Materials in Medicine 17, 259-266. 

Looking beyond ceramic materials to elec-trets, polymer and elastomeric piezoelectric materials, and so-caUed electroactive materials, a wide-open field of research in high-strain piezoelectric materials is appearing. Using the same technology to manipulate the chemical and physical stractures of complex ionic or nanotube-imbibed polymers, strains of well over 50 % have been obtained in this new class of material, many examples of which are biocompatible. Improvements in reliability, tolerance of extreme ambient conditions, and modeling are important areas that remain to be considered. 

PolyhydroxyaUcanoates (PHAs) are the biopolymers possessing the material properties ranging from rigid and highly crystalline to flexible, amorphous, and elastomeric. Because of such properties and inherent biodegradability, PHAs have attracted the world-wide attention of scientists and researchers as environment-friendly alternative to the conventional petroleum-based polymers. Polyhydroxybutyrate (PHB) and polyhydroxyoctanoate (PHO) have been found to possess biocompatibility in mammalian systems. Such biomaterials have got great potential as medical implantation devices [78-81]. 

Substrata expected to be useful in future cytology and regenerative medicine will be transparent, flexible, and stretchable (i.e., elastomeric) biocompatible materials that are also capable of forming various shapes (such as thin films, rods, spheres, and hollow tubes) so that they can be utilized in vivo or in vitro under various static and dynamic conditions. Mechanically tough M-NC films can be used as novel soft, transparent, and elastomeric hydrophobic substrates that satisfy all the requirements described above, as well as having capabilities for cell cultivation and subsequent cell detachment (and therefore for harvesting living cells), without the use of an enzyme treatment [33]. 

The development of soft-tissue engineering needs bioresorbable materials exhibiting elastomeric properties. Elastomeric polyurethane (PU) vascular grafts can withstand the action of stress and load and undergo an elastic recovery with little or no hysteresis. In recent years, biocompatible and biodegradable segmented polyurethanes (SPUs) have been studied for applications in the tissue engineering field. 

Polyphosphazenes bearing fluoroalkoxy side groups are among the most hydrophobic synthetic polymers known, and are bioinert. These polymers are as hyrophobic as polytetrafluoroethylene but, unlike Teflon, are flexible or elastomeric, easy to prepare, and can be used as coatings for other materials. They are highly biocompatible and therefore have been proposed as good candidates for use in heart valves, heart pumps, blood vessel prostheses, or as coating materials for pacemakers or other implantable devices. 

The biocompatible dimerized fatty acid (DFA)-based poly(aliphatic-aromatic ester) elastomers (PED) have been synthesized and studied for biomedical applications by El Fray et al. [194-200]. The design of nanostructured elastomeric biomaterials (mimicking biological materials) has been realized by using renewable resources, i.e., DFA. They are prepared by transesterification and polycondensation from the melt (see Section 7). The exceptional properties of DFA, e.g., excellent resistance to oxidative and thermal degradation, allow the preparation of PEDs without the use of thermal (often irritating) stabilizers. This is a particularly important feature making these polymers environmentally friendly and additive-free. What is equally important, by the use of the same method and stabilizer-free conditions, it was possible to prepare specially modified PED copolymers with an increased surface hydrophobicity. 

The most popular polymers used to fabricate lab-on-a-chip structures are polyfdi-methylsiloxane) (PDMS), polyfmethyl methacrylate) (PMMA), high-density polyethylene, low-density polyethylene, polyamide 6, and the epoxy-based photoresist SU-8 (Becker, 2002). Particularly, PDMS has been widely reported for miCTofluidic systems because it has many favorable properties for prototypes fabrication the material is inexpensive, optically transparent to visible Ught, which makes it compatible with optical detection systems, and also biocompatible its molding procedure is safe and easy to learn and its flexibility allows the integration of elastomeric actuators and optical elements into devices. 

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