Bone response to nano-apatite paste derived from Ca-amino acid complex

Abstract

Nano-apatite could be prepared from a homogeneous solution of calcium (Ca)-aspartic acid (Asp) and Caglutamic acid (Glu) chelate complex with a high yield. Asp and Glu are components of non-collagenous proteins. Arginine is used to adjust pH to obtain precipitation from a Ca complex solution. Apatite from a Ca-ethylenediaminetetraacetic acid (EDTA) chelate complex was also prepared. These apatites are referred to as Asp-HA, Glu-HA, and EDTA-HA, respectively. Nano-apatite paste was obtained after mixing with water. Synthesized nano-apatite was characterized by X-ray diffraction and Fourier transform infrared measurements. It was revealed that Asp-HA and Glu-HA showed smaller crystal sizes with nano-scale, higher lattice distortion and greater degree of consistency as compared to EDTA-HA. The elution of Ca ion forms Asp-HA and Glu-HA were smaller than that of EDTA-HA. To investigate the influence of the different amino acid ligands for calcium on bone response, bone responses to each nano-apatite paste were evaluated after transplantation into the subperiosteal pocket of the rat calvarial skeleton. Asp-HA and Glu-HA showed greater amounts of new bone formation than EDTA-HA. New bone formation progressed at an especially early stage after implantation with Asp-HA. It is suggested that Asp-HA paste will be useful for bone regeneration.