Nanostructures of Hydroxyapatite in Pluronic F 127: Preparation and Structural Characterization

Abstract

In this work, nanocomposites of hydroxyapatite and Pluronic F127 were prepared by a wet chemical method, using acid-basic reaction with Ca/P ratio of 1.67 in 10% (m/V) Pluronic F127 at 0, 37 and 90°C. The final concentration of Pluronic F127 was adjusted to 37% (m/V) at 4°C. Afterwards, the samples were lyophilized. Characterization was performed in purified samples (after Pluronic F127 removal), samples with 10% (m/V) of Pluronic F127 and calcined samples at 1000°C by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). Analyses by XRD of non-calcined samples showed that hydroxyapatite was obtained, in which the samples prepared at 0°C exhibited larger peaks attributed to lower crystallite sizes. For the calcined samples, both Raman spectroscopy and XRD exhibited hydroxyapatite for the syntheses at 37 and 90°C whereas the one prepared 90°C were identified as β-tricalcium phosphate (β-TCP). Morphological analysis by SEM indicated that the hydroxyapatite was sphere or rod agglomerates in mesoporous morphology for the nanocomposites prepared at 0 and 37°C, while the sample prepared at 90°C was nanospheres agglomerated into a smother matrix. After Pluronic F127 removal, samples fabricated at 0 and 37 °C exhibited coalescence of the nanostructures, whereas the sample synthesized at 90°C kept mesoporous. Calcined samples showed sintering and some rods structures.