Nano-carbonated hydroxyapatite precipitation from abalone shell (<i>Haliotis asinina</i>) waste as the bioceramics candidate for bone tissue engineering

In this study, nano-carbonated hydroxyapatite (n-CHAp) was successfully synthesized with abalone shells (Halioitis asinina) as the calcium source using precipitation methods with aging time variations, namely, 0 (without the aging process), 24, and 48 h. Based on an analysis of X-ray diffraction characterization, the spectrum of the n-CHAp is shown for all sample variations in aging time. The results of the calculation of lattice parameter values confirm that the phase formed is the B-type CHAp phase with the increasing crystallinity degree, crystallite size, particle size, and polydispersity which is confirmed by the presence of the CO32- functional group at 1438 cm(-1) and 878 cm(-1), that is, the B-type carbonate substitution characteristic. The presence of the carbonate ions identified as smaller during the extension of aging time causes the decreasing value of the Ca/P mole ratio but still has a value greater than the HAp Ca/P value (1.67), which is 1.80-1.72. Based on the transmission electron microscopy analysis, the nanometer-size of B-type CHAp particles was successfully obtained. According to the criteria for nanostructures, crystallographic properties, carbonate content, and chemical processes, B-type CHAp samples based on abalone shells (Halioitis asinina) are one of the candidates in bioceramics for bone tissue engineering applications.