Medical applications physical modifications

Composites utilizing cellulose fibers have been prepared with many different materials, especially polymers. It has been well demonstrated that these fibers help to alter and in general enhance the physical properties of polymeric composites [140, 149-157]. Additionally, their bio-degradability and biocompatibility enables cellulose-reinforced materials to be suitable for bio-scaffolding in medical applications, if the polymeric component is also biocompatible [140, 158]. Some surface modifications have been performed on cellulose to add selected characteristics, such as antimicrobial properties to polymeric matrixes [140,159]. 

Basnett et al. [110] reported novel poly(3-hydroxyoctanoate), P(3HO), and microbial cellulose composites and showed the addition of microbial cellulose has resulted in properties that are highly desirable for medical applications, including the development of biodegradable stents. Poly 3-hydroxyoctanoate) is hydrophobic in nature, whereas microbial cellulose is extremely hydrophilic in nature, hence chemical modification of microbial cellulose is required to achieve compatibility with the poly(3-hydroxyoc-tanoate) matrix to prepare a homogenous composite. The composite was prepared by physical blending of modified microbial cellulose microcrystals and poly(3-hydroxyoc-tanoate) and solvent cast into two-dimensional composite Aims. Yoxmg s modulus and glass transition temperature of the poly(3-hydroxyoctanoate)/microbial cellulose... 

This chapter begins with a review of other UHMWPE orthopedic implant surface modifications, the properties of HA, and the medical applications of HA. The synthesis and processing of UHMWPE/H A biomateiials is then described, followed by the chemical, physical, mechanical, and tribological characterization of the UHMWPE/HA biomaterials. Finally, the sterilization, biocompatibihty, and commerciah-zation of the UHMWPE/HA biomaterials are covered. 

Poly(2-hydroxyethyl methacrylate) (pHEMA) is a nonbiodegradable material. One of pHEMA s physical characteristics is that it is easily tailorable, and been used extensively in medical applications. Tsai et al. implanted poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (pHEMA-MMA) hydrogel guidance channels into a T8 transected spinal cord in adult Sprague-Dawley rats the hydrogel guidance channel improved specific supraspinal and local axonal regeneration after complete spinal cord transection (Tsai et al. 2004). In another study, modifications of pHEMA with cholesterol and laminin have... 

As the basic component of medical textile materials, the structures and properties of the constituent polymers have a significant effect on the biodegradability, biocompatibility, absorbency, antimicrobial property, and other functional performances of the final medical textile products. Functional modifications of polymers have far-reaching effects on the fibers, yams, fabrics, and textile materials that are processed in a series of downstream operations. In order to generate the desired product performance characteristics for their diverse applications such as hygiene, protection, therapeutic, nonimplantable or implantable materials, extracorporeal devices, etc., the chemical and physical structures of the relevant polymers should be engineered to suit their required specifications. 

This chapter will focus on fundamental concepts related to surface modification of materials utilized within polymeric biocomposites for orthopedic applications. For this chapter, orthopedic applications are defined as medical indications or procedures that benefit from utilization of polymeric biocomposites and/or additional implanted therapeutic material to aid in bone regeneration at a localized site. The term surface modification refers to the physical attachment of molecules, predominantly silanes and/or polymers, to the surface of a solid-phase material. Polymeric biocomposites are a class of biomaterials that comprises a biocompatible bulk polymer and a particulated solid phase, often referred to as a binder and a filler, respectively. As there are vast combinations of polymers and solid materials that fit this definition, this chapter highlights solely those combinations that have been utilized for orthopedic applications, in either the acadenuc or the medical industry settings. 

The ultrathin fibrillar structures (fibers, medical threads, meshes, mats and scaffolds) are of utmost interest as the modem functional materials with specific properties such as the high surfaceA olume ratio of a single filament, effective surface modification, special physical-chemical behavior, and anomalous diffusion [1-5]. At the present time ultrathin fibers and articles on their base are efficiently applicable in biomedicine, tissue engineering, in filtration and separation processes, for composite design, in electronics, analytical supplies, sensor-based diagnostics, and in other iimovative applications [6-9]. 

The modification of polymer strueture using radiation technology has been practiced extensively in industry to enhance the physical properties of the final products in many applications, such as wire and cable, electronics, medical and marine [1,2]. 

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