Tissue-implant interface biomaterials

Biomaterial scientists and engineers are currently investigating novel formulations and modifications of existing materials that elicit specific, timely, and desirable responses from surrounding cells and tissues to support the osseointegration of the next generation of orthopedic and dental biomaterials (Ratner, 1992). Enhanced deposition of mineralized matrix at the bone-implant interface provides crucial mechanical stability to implants. Proactive orthopedic and dental biomaterials could consist of novel formulations that selectively enhance osteoblast function (such as adhesion, proliferation and formation of calcium-containing mineral) while, at the same time, minimize other cell (such as fibroblast) functions that may decrease implant efficacy (e.g., fibroblast participation in callus formation and fibrous encapsulation of implants in vivo). 

Basically, all of the events occurring at the tissue-miaterial interface can be categorized as biological responses toward the implant material (host tissue responses) and, conversely, material responses to the host tissue [62], These two categories can be further viewed from the host tissue and the biomaterial perspectives as illustrated in Figures 1.12 and 1.13, respectively. 

Textor, M. Tosatti, S. Wieland, M. Brunette, D. M. nBio-Implant Interface Improving Biomaterials and Tissue Reaction Lyngstadaas, E., Ed. CRC Press Boca Raton, FL (in press). 

Ellingsen JE, Lyngstadaas SP. In Bio-implant interface improving biomaterials and tissue reactions. Boca Raton, FL CRC Press 2003. 

Wolpaw, J.R., N. Birbaumer, DJ. McFarland, G. Pfurtscheller, and T.M. Vaughan. 2002. Brain-computer interfaces for communication and control. Clinical Neurophysiology 113(6) 767-791. Yuen, T.G., W.F. Agnew, and L.A. Bullara. 1987. Tissue response to potential neuroprosthetic materials implanted subdurally. Biomaterials 8(2) 138-141. 

Several effects of fluoride ions have been claimed (Table 1) concerning the stability of the biomaterials, the implant-tissue interface, or the tissue itself. The incorporation of fluoride ions in apatitic materials is generally aimed at increasing their stability and decreasing their solubility. 

Biocompatibility (See Table 1), which is a phenomenological concept, is the essential property of biomaterials. For instance, the inner surface of an implanted vascular graft or blood pump (artificial heart) must be blood-compatible, while its outer surface must be tissue-compatible. In other words, the material surfaces must not exert any adverse elfects upon blood or tissue, or upon other biological elements at the interfaces. 

It is often demanded that the surface of polymeric biomaterials should exhibit permanent tenacious adhesion to soft connective and dermal tissues. However, conventional non-porous, polymeric materials will be encapsulated by a fibrous membrane generated de novo by surrounding fibroblasts, when subcutaneously implanted into the living body in contact with soft connective tissues. This is a typical foreign body reaction of the living system to isolate foreign materials from the host inside the body. On the other hand, it should be noted that the small gap present between a percutaneously-implanted device and the surrounding tissue provides a possible route for bacterial infection because of the lack of microscopic adhesion at the interface. 

The aim of this paper is to present the use of a microwave digestor to prepare nanopowders via hydrothermal route. In the field of biomaterials the researchers (due to some problems with the traditional materials) are looking for the design of biomaterials with surface properties similar to physiological bone (grain sizes in the nanometric range [5]). This would aid in the formation of new bone at the tissue/biomaterial interface and therefore improve implant efficacy. With the advent of nanostructured materials (materials with grains sizes less than 100 nm in at least... 

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