Synthesis of Brushite Particles in Reverse Microemulsions of the Biosurfactant Surfactin

Abstract

In this study the “green chemistry” use of the biosurfactant surfactin for the synthesis of calcium phosphate using the reverse microemulsion technique was demonstrated. Calcium phosphates are bioactive materials that are a major constituent of human teeth and bone tissue. A reverse microemulsion technique with surfactin was used to produce nanocrystalline brushite particles. Structural diversity (analyzed by SEM and TEM) resulted from different water to surfactin ratios (W/S; 250, 500, 1000 and 40,000). The particle sizes were found to be in the 16–200 nm range. Morphological variety was observed in the as-synthesized microemulsions, which consisted of nanospheres (~16 nm in diameter) and needle-like (8–14 nm in diameter and 80–100 nm in length) noncalcinated particles. However, the calcinated products included nanospheres (50–200 nm in diameter), oval (~300 nm in diameter) and nanorod (200–400 nm in length) particles. FTIR and XRD analysis confirmed the formation of brushite nanoparticles in the as-synthesized products, while calcium pyrophosphate was produced after calcination. These results indicate that the reverse microemulsion technique using surfactin is a green process suitable for the synthesis of nanoparticles.

Effect of preparation conditions on the nanostructure of hydroxyapatite and brushite phases

“…Moreover, band near to 1064 cm -1 is reffered to the m 3 stretching mode of the PO 4 3-group. A band around 1132 cm -1 was attributed to the m 0 6 and m 00 6 of HPO 4 2-ions in brushite (Maity et al 2011). Further investigation of the FTIR spectra revealed that the band at 1649 cm -1 was ascribed to the bending mode of H 2 O.…”

“…; monotite (DCPA) and brushite. A band at 989 cm -1 is assigned from the P-O(H) symmetric stretching vibration of PO 4 3-group (Singh et al 2010;Maity et al 2011). Moreover, band near to 1064 cm -1 is reffered to the m 3 stretching mode of the PO 4 3-group.…”

Hydrothermal processing of hydroxyapatite nanoparticles—A Taguchi experimental design approach

“…(2); this was then followed by the second region of weight loss over the temperature range of 400-450 1C due to the dehydration of HPO 4 2 À ions. Table 3, the sample H4-20-100-60 was pure DCPA and the two other samples had a certain amount of DCPA in their crystal structure; hence, the concurrent weight loss in DCPA containing samples could only be explained by the conversion of DCPA to calcium pyrophosphate, according to the following equation [38,43]:…”

Complex phase evolution of Brushite-based calcium phosphate CaHPO4·2H2O using in situ high temperature X-ray diffraction and thermal analysis

“…At 375 °C (Fig. 7c), the at plate morphology of DCPD disappears completely in favor of large particles of different sizes asserting the presence of CPP phase, as shown generally in CPP materials [48,49]. The texture of the particles becomes well organized when the heating temperature reaches 450 °C indicating the appearance of the LT-CPP phase (γ-CPP) (Fig.…”