Nanophase ceramics surfaces

Burggraaf, A. J., K. Keizer and B. A. van Hassel. 1989a. Nanophase ceramics, membranes and ion implanted layers. Paper read at S.I.C. Mat. 88-Nato ASl, Surfaces and interfaces of ceramic materials, 4-16 September 1988, lie d 01eron. 

A. Surface Properties of Nanophase Ceramics for Enhanced Orthopedic and Dental Implant Efficacy... 

Enhanced osteoblast and osteoclast functions on nanophase ceramics due to increased surface wettability. Compared to conventional ceramics, nanophase ceramics exhibit enhanced surface wettability [evidenced, for example, by aqueous contact angles three times smaller... 

Fig. 11. Unfolding of vitronectin exposes epitopes for osteoblast adhesion on nanophase ceramics. Schematic representation (not in scale) of a possible mechanism for enhanced osteoblast adhesion on (a) nanophase, compared to (b) conventional, ceramics, which involves unfolding of the vitronectin macromolecule to expose select cell-adhesive epitopes (such as arginine-glycine-aspartic acid) for osteoblast adhesion. Increased exposure of cell-adhesive epitopes of vitronectin for enhanced osteoblast adhesion on nanophase ceramics may be due to nanometer surface topography and/or increased wettability due to the greater number of grain boundaries at the surface.

Due to their ability to selectively promote both osteoblast and osteoclast function, nanophase ceramics provide a preferable alternative to conventional orthopedic and dental implants that fail to integrate with surrounding bone it is undoubtedly highly desirable to minimize, if not avoid, clinical complications that necessitate removal of failed implants as a result of poor surface properties that lead to insufficient osseointegration. These results provide evidence that nanoceramics may be synthesized to match surface properties of bone and, thus, demonstrate strong promise and potential for their use in orthopedic and dental applications. 

Undoubtedly, changes in porosity (such as bulk and surface porosity and diameter of individual pores) of nanophase ceramic formulated by Webster et al. (1999) provide an explanation for the observed differences in mechanical properties of respective nanophase and conventional ceramic formulations for example, individual surface pores four times smaller were achieved in nanophase (67-nm grain size) compared to conventional (179-nm grain size) HA formulations (Webster et al., 2000a). Compared to conventional formulations, therefore, the bending modulus of nanophase ceramics... 

Nanoparticles, see Supported nanoparticles Nanophase ceramics adhesion of osteoblasts to ceramic surfaces, 152-153 bending properties, 158 enhancing osteoblast and osteoclast functions, 153-155... 

Metallic nanopartides were deposited on ceramic and polymeric partides using ultrasound radiation. A few papers report also on the deposition of nanomaterials produced sonochemically on flat surfaces. Our attention will be devoted to spheres. In a typical reaction, commerdally available spheres of ceramic materials or polymers were introduced into a sonication bath and sonicated with the precursor of the metallic nanopartides. In the first report Ramesh et al. [43] employed the Sto-ber method [44] for the preparation of 250 nm silica spheres. These spheres were introduced into a sonication bath containing a decalin solution of Ni(CO)4. The as-deposited amorphous clusters transform to polyciystalline, nanophasic, fee nickel on heating in an inert atmosphere of argon at a temperature of 400 °C. Nitrogen adsorption measurements showed that the amorphous nickel with a high surface area undergoes a loss in surface area on crystallization. 

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