Biomaterial prosthesis

Inflammation is generally defined as the reaction of vascularized living tissue to local injury, that is, implantation of a biomaterial, prosthesis, medical device, or tissue-engineered device. Immediately following injury, blood-material interactions occur and a provisional matrix is formed that consists... 

Biomaterials. Just as stem designs have evolved in an effort to develop an optimal combination of specifications, so have the types of metals and alloys employed in the constmction of total joint implants. Pure metals are usually too soft to be used in prosthesis. Therefore, alloys which exhibit improved characteristics of fatigue strength, tensile strength, ductihty, modulus of elasticity, hardness, resistance to corrosion, and biocompatibiUty are used. 

De Groot JH, de Vrijer R, Pennings AJ, Klompmaker J, Veth RPH, and Jansen HWB. Use of porous polyurethanes for meniscal reconstruchon and meniscal prosthesis. Biomaterials, 1996, 17, 163-174. Borkerhagen M, Stoh RC, Neuenschwander P, Suter UW, and Aebischer P. In vivo performance of a new biodegradable polyester urethane system used as a nerve guidance channel. Biomaterials, 1998, 19, 2155-2165. 

A significant contribution of Raman spectroscopy to the analytical characterization of biomedical issues has been made in the area of biomaterials, especially in the identification of biodegradation and deterioration [1, 2]. The general impact of Raman spectroscopy on the study of biomaterials has been described by this author in three recent review articles [3-5]. In this chapter, the topic of Raman characterization of biomaterials is revisited with particular emphasis placed on those biomaterials widely employed for load-bearing surfaces in artificial joints. Important recent case studies are presented to illustrate the power of the Raman technique to answer key questions of broad medical, scientific, and technological interest. The analytical and physical science lying behind the Raman effect is shown to contribute to the accumulation of a wealth of fundamental information about the medical and technical achievements of prosthesis makers. 

Implantation materials, which are in direct contact with blood, have to meet a particularly large range of requirements bio- and blood compatibility, mechanical strength against blood pressure, impermeability to the blood and its constituents, and sterilizability. In addition, the healing process that takes place on the inner and the outer surface of the artificial vessel is very different. The inner surface of the biomaterial should not stimulate adhesion of cellular blood components but should be covered with endothelial cells, whereas the outer surface of the prosthesis should be wrapped with connective tissue. 

The first implanted synthetic polymeric biomaterial appears to be PMMA, which was used as a hip prosthesis in 1947 (see USP XVIII, The Pharmacopia of the USA, (18th Revision), US Pharmacopoeial Convention, Inc., Rockville, MD, 1 September 1980). Polyethylene, and then other polymers, were used as implants in the middle ear in the early 1950s, yielding good initial results, but local inflammation limited the use of these materials. 

Bioadhesion, i.e. biofihn formation resulting in a fouling surface, is required for biomaterial to be considered as a part of the body (e.g., orthopedic prosthesis, hard tissue) to enhance its incorporation and its biomechanical response. Examples are in the rebuilding of bones, recolonization, and hybrid implants composed of two parts, a synthetic one (with polymers as the mechanical sub-... 

The Neural Prosthesis Program, launched in 1972 and spearheaded by F. Terry Hambrecht, MD, brought funding, focus, and coordination to the multidisciplinary effort to develop technologies to restore motor function in paralyzed individuals. The initial efforts were in electrode-tissue interaction, biomaterials and neural interface development, cochlear and visual prosthesis development and control of motor function using implanted and nonimplanted electrodes. 

E. L. Chaikof, The effect of a recombinant elastin-mimetic coating of an ePTFE prosthesis on acute thrombogenicity in a baboon arteriovenous shunt. Biomaterials 28 (2007) 1191-1197. 

T. Mackay, D. Wheatley, G. Bernacca, A. Fisher, C. Hindle, New polyurethane heart valve prosthesis design, manufacture and evaluation, Biomaterials 17 (19) (1996) 1857-1863. 

R Langone, et al.. Peripheral nerve repair using a poly(organo)phos-phazene mbular prosthesis. Biomaterials 16 (5) (1995) 347—353. 

Another ophthalmologic application of polymeric biomaterials is the development of ocular prosthesis and biologically inspired compound eyes [197,198]. Such prostheses, commonly fabricated from porous polyethylene, are designed to serve as nonfunctional artificial substitutes for enucleated eyeballs [199]. 

L. Costa, M.P. Luda, L. Trossarelli, E.M. Brach del Prever, M. Crova, P. Gallinaro, In vivo UHMWPE biodegradation of retrieved prosthesis, Biomaterials 19 (1998) 1371-1385. 

The identification of the fundamental biological requirements of a biomaterial first requires an identification of how the biomaterial is to be used and in what type of implant medical device or prosthesis the biomaterial is to be used. Having identified the intended application of the biomaterial, the identification of the tissues that will contact the biomaterial and the implant duration of the biomaterial, medical device or prosthesis is necessary. Once these parameters have been defined, appropriate in vitro and in vivo assays can be sdected to identify the success or failure of the biomaterial and its intended application. A broad perspective in the selection of in vitro and in vivo biocompatibility assays is necessary to not only identify adverse reactions but also identify reactions that indicate the successful function of the biomaterial in its intended application. Adverse tissue responses do not necessarily reject a biomaterial from use in a medical device or prosthesis. Adverse tissue responses do require a risk... 

Costa L., P. Bracco, E.M. Brach del Prever, et al. 2001. Analysis of products diffused in UHMWPE prosthesis components in vivo. Biomaterials 22 307-315. 

Patents over the last few years dealing with BNC biomedical applications illustrate the scientific advances herein reviewed, such as uses of BNC in composite materials for use in osseous tissue support material, blood vessel prosthesis, artificial skin, cartilage-like biomaterial, implan Czaja support material used for cornea, cartilage connective tissue and ligament repair cement for fixing bones, etc. [54]. 

Zhang, Z., Marois, Y., Guidoin, R. G., Bull, P., Marois, M., How, T., Laroche, G., and King, M. W., Vascugraft polyurethane arterial prosthesis as femoro-popliteal and femoro-peroneal bypasses in humans Pathological, structural and chemical analysis of four excised grafts, Biomaterials, 1997 18(2) 113-124. 

Alumina and zirconia ceramics are also being used for alveolar ridge reconstruction (20), maxillofacial reconstruction, as ossicular bone substitutes (21), and in ophthalmology (22), knee prosthesis (8), bone screws as well as other applications as dental biomaterials, such as dental crown core, post, bracket and inlay (23,24). 

The thermal properties of polymers are important parameters to consider as they play key roles in the mechanical properties of biomaterials used in bone repair and prosthesis materials. These properties may also influence the drug-release properties of drug-delivery devices. Information is provided about the mobility of the polymer chains within a material at a given temperature and about the crystallinity of this material (see also Section 2.4). This characterisation is also useful in order to determine whether a polymer material is a hard or soft solid or a liquid at a given temperature. 

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