Chapter 2 - Bio-nanoceramics and Bio-nanocomposites

Abstract

The class of ceramics used for repair and replacement of diseased and damaged parts of musculoskeletal systems are termed bioceramics. Bioceramics range in biocompatibility from the ceramic oxides, which are inert in the body, to the other extreme of resorbable materials. To the most used bioresorbable ceramics belong calcium orthophosphates, represented by hydroxyapatite (HA). In past decades, many different methods have been introduced and presented for preparing HA nanoparticles with precise control for microstructure, particle shape and size. Mineral phase can be also obtained from a wide range of natural sources, called as bioapatite (BAp), as an alternative to processes for preparing synthetic apatite. It is believed that nanosized BAp isolated or prepared from biogenic sources is the best material for tissue replacement and regeneration. It exhibits enhanced resorbability and much higher bioactivity than micron-sized or synthetic HA. The release of calcium ions from nanosized BAp is also similar to the behaviour of the apatitic phase in real tissue. In recent decades, a number of isolation and preparation routes for producing BAp have been developed and published. This chapter will summarize recent and very recent work on isolating and preparing bioapatites from various natural sources. First, the physicochemical properties of bioapatites will be briefly described. Then a general summary of natural, that is animal (mammalian, birds, reptiles, fish, corals, cephalopoda, mussels, sea urchins) and vegetal (fruit and vegetable peels, flowers, leaves, stalks) sources for bioapatite production from various environments, such as terrestrial (animal bones and eggshells, vegetation) and water (animal bones, scales and exoskeletons, water weeds) will be made. Special attention will be paid to describing individual methods for acquiring bioapatite from biogenic sources, that is direct isolation of bioapatite, and indirect biomimetic synthesis with the aid of naturally derived biomolecules or biomembranes.