Polymeric biomaterials, classes

The polymeric/ soft materials chapter represents the largest expansion for the 2nd edition. This chapter describes all polymeric classes including dendritic polymers, as well as important additives such as plasticizers and flame-retardants, and emerging applications such as molecular magnets and self-repairing polymers. This edition now features click chemistry polymerization, silicones, conductive polymers and biomaterials apphcations such as biodegradable polymers, biomedical devices, dmg delivery, and contact lenses. 

Polymers, both synthetic and natural, are the most diverse class of biomaterials. Polymeric biomaterials are widely used in both medical and pharmaceutical applications, and contribute significantly to the quality and effectiveness of health care. They are available in a wide variety of compositions and properties. They can readily be processed to form complex shapes with any size according to their final application. In addition, their surface properties, which are important in biological applications, may be readily modified by physical, chemical, or biochemical means. Their main disadvantage is the extractables in their structures (remaining after synthesis or fabrication processes), which may leach out during the use, and may lead undesirable effects on the host. 

Abstract In this paper the synthesis, properties and applications of poly(organophos-phazenes) have been highlighted. Five different classes of macromolecules have been described, i.e. phosphazene fluoroelastomers, aryloxy-substituted polymeric flame-retardants, alkoxy-substituted phosphazene electric conductors, biomaterials and photo-inert and/or photo-active phosphazene derivatives. Perspectives of future developments in this field are briefly discussed. 

On this basis, five classes of different polyphosphazenes are considered as outstanding examples of this type of macromolecules, in which skeletal and substituent features overlap to the highest extent. The reported materials are elastomers, flame retardants and self-extinguishing macromolecules, polymeric ionic conductors, biomaterials, and photosensitive polymeric compounds all of them based on the polyphosphazene structure. 

In dentistry, silicones are primarily used as dental-impression materials where chemical- and bioinertness are critical, and, thus, thoroughly evaluated.546 The development of a method for the detection of antibodies to silicones has been reviewed,547 as the search for novel silicone biomaterials continues. Thus, aromatic polyamide-silicone resins have been reviewed as a new class of biomaterials.548 In a short review, the comparison of silicones with their major competitor in biomaterials, polyurethanes, has been conducted.549 But silicones are also used in the modification of polyurethanes and other polymers via co-polymerization, formation of IPNs, blending, or functionalization by grafting, affecting both bulk and surface characteristics of the materials, as discussed in the recent reviews.550-552 A number of papers deal specifically with surface modification of silicones for medical applications, as described in a recent reference.555 The role of silicones in biodegradable polyurethane co-polymers,554 and in other hydrolytically degradable co-polymers,555 was recently studied. 

By definition, mucoadhesive hydrogels are a class of polymeric biomaterials that exhibit the basic character- 2. 

Among the many classes of polymeric materials now available for use as biomaterials, non-degradable, hydrophobic polymers are the most widely used. Silicone, polyethylene, polyurethanes, PMMA, and EVAc account for the majority of polymeric materials currently used in clinical applications. Consider, for example, the medical applications listed in Table A.l most of these applications require a polymer that does not change substantially during the period of use. This chapter describes some of the most commonly used non-degradable polymers that are used as biomaterials, with an emphasis on their use in drug delivery systems. 

Polyphosphoesters form another interesting class of biomaterials that is composed of phosphorous-incorporated monomers (Figure 30.4m). These polymers consist of phosphates with two R groups (one in the backbone and one side group) and can be synthesized by a number of routes including ring-opening polymerization, polycondensation, and polyaddition. - - ... 

Characterization of polymeric biomaterials is more challenging than that of other classes of biomaterials like metals, alloys, glasses, and ceramics, owing to their dynamic... 

Biochemical Effects of Host Environment 19.5 Emerging Classes of Polymeric Biomaterials for ... 

This chapter addresses the application of polymeric biomaterials in the context of implantable devices intended for long-term functionality and permanent existence in the recipients. Basic concepts of biocompatibility as well as mechanical and structural compatibility are discussed to provide appropriate background for the understanding of polymer usage in cardiovascular, orthopedic, ophthalmologic, and dental prostheses. Furthermore, emerging classes... 

EMERGING CLASSES OF POLYMERIC BIOMATERIALS FOR IMPLANTABLE PROSTHESES... 

Microcellular materials exist in many forms. Methods for production of these materials are as varied as potential applications. This chapter reviews the technology of one class of microcellular materials, microcellular foams, which are sought for biomedical applications. Included is a description of several methods of foam production, foam morphologies, and present uses for microcellular foam materials. New methods of microcellular foam production and potential uses for the resultant foam materials are important to those interested in biomaterials and contemporary biomedical applications. It is for this reason that advances in microcellular foam formation are emphasized in the final section of this chapter. Increasingly, it is becoming evident that microcellular foams can be used effectively in many medical applications, particularly polymeric foam materials which are being investigated in this laboratory. For this reason, the focus of this chapter pertains to possible biomedical applications of polymeric microcellular foams. 

Tangpasuthadol, V., et al. 2000. Hydrol3dic degradation of tyrosine-derived polycarbonates, a class of new biomaterials. Part II 3-yr study of polymeric devices. Biomaterials 21(23) 2379-2387. 

Sabbatini, L., Zambonin, RG. (1996) XRS and SIMS surface chemical analysis of some important classes of polymeric biomaterials. J. Electron. Spectrosc. Relat. Phenom., 81, 285-301. 

Medical and dental materials are in the class of materials called biomaterials. Biomateiiab are used in the body to replace body components or assist in retaining or restoring body functions. Biomaterials include synthetic materials, modified natural materials, biosynthetic materials, systems engineered materials, and morphological protein molecules that can send signals of direction to cells [7]. Synthetic biomaterials may be metallic, ceramic, polymeric, or a combination of these as needed to meet the needs of intended application. 

NO-releasing biomaterials have been developed for antibacterial applications including polymeric materials, xerogel, sol gel,i i and silica nanoparticles. Two different classes of NO donors, diazeniumdiolates and nitrosothiols, are commonly used. The diazeniumdiolates, also called as NONOates, are synthesized by reaction of amines with NO gas to form relatively stable compounds that spontaneously release NO on contact with bodily fluids. 

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