Metallic biomaterials

Metallic biomaterials (metals such as Ti or its alloys and others) are used for the manufacture of orthopaedic implants due to their excellent biocompatibility with respect to electrical and thermal conductivity and their mechanical properties, e.g., for hard tissue replacement such as total hip and knee joints, for fracture healing aids such as bone plates and screws or dental implants. For example, Co-Cr-Mo alloys are employed for metal-on-metal hip bearings in total joint replacements. Problems with implants occur because of ion release in patients with metal implants. To control this ion release, the ultratrace determination of Co, Cr and Mo in the blood (or serum) and urine of patients with Co-Cr-Mo alloy hip implants is carried out routinely in the author s laboratory. The trace metal determination of Co, Cr and Mo in complex matrices such as urine and blood by ICP-MS is not trivial due to the low concentrations expected in the sub-ngmF1 range, the possible danger of contamination during sample collection, sample preparation and the... 

Biocompatibility essentially means that the material produces no adverse response from the body this may be toxic, allergenic, carcinogenic, or mechanical. However, the body can tolerate even nonbiocompatible materials if the quantity of the material is small enough. Adverse responses can arise in response to chemical or particulate products that are released from a biomaterial. Metals, for example, are particularly susceptible to corrosion by body fluids, and the products of corrosion, such as metallic ions, salts, and oxides, can induce an immune response. Particles, resulting from mechanical wear of an implant, may also invoke an immune response, even if this would... 

An expanding area of opportunity for organic synthesis is materials chemistry. The surge of interest in electronic devices, biomaterials, metal receptors, fullerenes, quantum dots, and more includes applications in indole chemistry. 

There are a wide range of substrates and films which can be produced as biomaterials. Metals such as titanium alloys are often used where high strength or toughness is required, such as hip implants. Their mechanical properties can be somewhat similar to bone, which makes them ideal candidates as structural bioimplants. However, as outlined by Skinner and Kay (2011), metal erosion can be a potentially dangerous problem. Ceramic films such as Ti02, Si02 or hydroxyapatite Caio(P04)6(OH)2 are often added to the surface to reduce wear of the implant and improve biocompatibUity. 

Z. J. Lelnikowski, DNA as a platform for new biomaterials. Metal-containing nucleic acids, Curr. Org. Chem.,lWl, //, 355-381. 

With the rich chemical properties of alkyne monomers, polymers with rare and complicated stmctures can be designed and synthesized via alkyne-based polymerizations. For instance, polyamidines are a series of important polymers with potential roles as biomaterials, metallic conductors, and photosensitive semiconductors their syntheses are limited to two-component, step-growth polymerization reactions [37, 38]. An efficient Cu-catalyzed MCR of alkynes, sulfonyl azides, and amines was recently reported by Chang and coworkers to afford a library of small-molecule amidines [3, 5], The reaction undergoes a Cu-catalyzed azide-alkyne... 

During the last 30 years, advances in material science have led to the development of synthetic materials that have unique properties for medical applications. Metals, ceramics, polymers, composites are the main classes of synthetic biomaterials. Metals and their alloys have been used in various forms as implants and for hard tissue repair (e.g., dental implants, joint replacement, fracture plates, screws, pins). They are mechanically strong, tough and ductile. They can be readily fabricated and sterilised. However, they may corrode in the biological media, their densities are high and their mechanical properties mismatch with bone, which may result undesirable destruction of the surrounding hard tissues. 

Polymers, metals, ceramics, and glasses may be utilized as biomaterials. Polymers (see Ppolymerprocessing), an important class of biomaterials, vary gready in stmcture and properties. The fundamental stmcture may be one of a carbon chain, eg, in polyethylene or Tedon, or one having ester, ether, sulfide, or amide bond linkages. PolysiHcones, having a —Si—O—Si— backbone, may contain no carbon. 

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. 

XPS has been used in almost every area in which the properties of surfaces are important. The most prominent areas can be deduced from conferences on surface analysis, especially from ECASIA, which is held every two years. These areas are adhesion, biomaterials, catalysis, ceramics and glasses, corrosion, environmental problems, magnetic materials, metals, micro- and optoelectronics, nanomaterials, polymers and composite materials, superconductors, thin films and coatings, and tribology and wear. The contributions to these conferences are also representative of actual surface-analytical problems and studies [2.33 a,b]. A few examples from the areas mentioned above are given below more comprehensive discussions of the applications of XPS are given elsewhere [1.1,1.3-1.9, 2.34—2.39]. 

Pourbaix, M., Electrochemical Corrosion of Metallic Biomaterials , Biomaterials, 5, 122-134 (1984)... 

Our inventory also showed that funding levels for materials vary widely across differing materials classes. R D on advanced metals received 13% (the largest fraction in 1992), composites were 11%, electronic materials were 10%, and biomaterials were also 10%. The FCCSET process proved enormously successful in focusing the federal program on materials research. 

Porath, J., and Olin, B. (1983) Immobilized metal ion affinity adsorption and immobilized metal ion affinity chromatography of biomaterials. Serum protein affinities for gel-immobilized iron and nickel ions. Biochemistry 22, 1621-1630. 

The suitable materials for the above mentioned domains are polymers, metals and ceramics. Among these, polymers play an important role. Even the polymers have a lot of remarkable properties that could be used in biomaterials design, the interaction between these artificial materials and tissues and blood could create serious medical problems such as clot formation, activating of platelets, and occlusion of tubes for dialysis or vascular grafts. In the last few years, novel techniques of synthesis have been used to correlate desirable chemical, physical and biological properties of biomaterials. 

Abstract Recently, the interest on biomaterials and especially in tannins was growing and some attractive results were obtained in the adsorption of some metals by tannin adsorbents. Tannins are widely distributed in nature and have multiple adjacent polyhydroxyphenyl groups in their chemical structure which have extremely high afiSnity for heavy metal ions. This study will describe how tannin can be used as an effective zinc and lead sorbent by the use of tannin resins. Batch method was used in the experiments in which pH profde, adsorption time, adsorbent/liquid ratios, initial concentration of metal ions, adsorbent amount and temperature were investigated to determine binding properties of adsorbent for the Zn(II) and Pb(ll) ions. 

Tarmins are important commercial products of complex and diverse chemistry. During the last years, the interest of biomaterials and specifically in tannins was growing. The ability of tannins to precipitate metal ions is due to their multiple adjacent phenolic hydroxyl groups, which can form stable complexes with many metal ions [8, 9]. 

Keywords Biomaterial, heavy metals, lead, resin, tannin, zinc... 

Recently, the interest on biomaterials and especially in tannins was growing and some attract results were obtained in the adsorption of some metals by tannin adsorbents [18]. Tannins are widely distributed in nature and have multiple adjacent polyhydroxyphenyl groups in their chemical stracture which have extremely high affinity for heavy metal ions [16, 19]. 

Another of the new techniques for extractive preconcentration, separation, and/or purification of metal chelates, biomaterials, and organic compounds is based on the use of surfactant micellar systems. 

Ben-Knaz R, Avnir D. (2009) Bioactive enzyme-metal composites The entrapment of acid phosphatase within gold and silver. Biomaterials 30 1263-1267. 

Fig. 1 Representative a Nyquist and b Bode plots from electrochemical impedance spectroscopy measurements (HubrechtJ (1998) Metals as Biomaterials, Helsen J, Breme H (eds) John WUey Sons Limited. Reproduced with permission)...

Hubrecht J (1998) In Helsen JA, Breme HJ (eds) Metals as Biomaterials. Wiley, Chichester... 

Many biomaterials are composites. Bone and skin are relatively light compared to metals. Composite structures can approach the densities of bone and skin and offer the necessary inertness and strength to act as body-part substitutes. 

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