Biomaterials Aspects of CaP Nanocarriers and Composites

Calcium phosphate ceramic particles present a unique class of biomaterials for orthopedic and dental applications owing to their wide range of properties that they possess from bioactive hydroxyapatite (Ca10(PO4)6(OH)2, HA, Ca/P = 1.66) to resorbable tricalcium phosphate (Ca3(PO4)2, TCP, Ca/P = 1.5). The mineral component of bone is essentially a calcium-deficient hydroxyapatite (Ca10-x (PO4)6-x (HPO4) x (OH) 2-x, 0 ≤ x ≤ 1, CDHA), which is structurally similar to stoichiometric HA but compositionally can be varied to the extent of TCP. Our activities on nanophase calcium phosphate ceramics and cements as bone substitutes in minor dental surgery will be reviewed. The eggshell waste has been value engineered to form nanophase HA as well as CDHA by accelerated processing. The eggshell derived apatites were also found to have minor constituent of Mg, Sr, Si and Na ions inherited from the eggshell. As these ions are of optimal composition for bio- mineralization of eggshells, the advantages of multi-ion substituted nanocrystalline apatites for bone regenerative applications will be highlighted. Bioresorbable CDHA nanoparticle based local delivery system with desired sustained drug release profiles seems to be an efficient way for the treatment of many bacterial bone infections such as periodontitits, osteomylitis, etc. The site specific and extended delivery of doxycycline and cephalexin drugs by CDHA nanocarriers will also be presented. Research pertaining to development of nanofibrous and nanocomposite through electrospinning of inorganic-organic hybrids which are potentially applicable to hard tissue engineering to encourage mineralization will be summarized.