Nanodimensional and Nanocrystalline Calcium Orthophosphates

Abstract

Nano-scaled particles and crystals play very important roles in biological systems. For example, calcium orthophosphates (CaPO4) with nano-size dimensions represent the basic inorganic building blocks of bones and teeth of mammals. According to recent discoveries in biomineralization, zillions of nanodimensional crystals of biological apatites are nucleated in body fluids, and afterward, they are self-assembled into these complex structures. In addition, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of CaPO4. All these effects are due to the higher surface-to-volume ratio, increased reactivity, and biomimetic morphologies of the nano-scaled particles. Thus, the nano-sized and nanocrystalline forms of CaPO4 have a great potential to revolutionize the hard tissue engineering field, starting from bone repair and augmentation to controlled drug delivery systems. Therefore, preparation and application of nanodimensional CaPO4 are the important topics in modern material science, and such formulations have been already tested clinically for various purposes. Currently, more efforts are focused on the possibility of combining nano-scaled CaPO4 with cells, drugs, and other biologically active substances for multipurpose applications. This chapter describes current state-of-the-art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications.