Article

Synthesis of Brushite Particles in Reverse Microemulsions of the Biosurfactant Surfactin

Department of Earth and Environmental Sciences National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 62102, Taiwan
International Journal of Molecular Sciences (Impact Factor: 2.86). 12/2011; 12(6):3821-30. DOI: 10.3390/ijms12063821
Source: PubMed

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.

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    • "The particles were reported to be homogeneous in size and were stable over a period of 2 months. Maity et al. (2011) synthesized crystalline calcium pyrophosphate nanoparticles of different morphologies by varying the water-to-surfactant (W/S) ratio in water/hexane/Surfactin reverse-microemulsion system. Nanoparticles with size distribution of 50–500 nm were obtained when the as-synthesized noncalcinated calcium phosphate (synthesized at room temperature) particles were subjected to calcination at a temperature of 800°C. "

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    • "In recent years, considerable efforts have been focused on using surfactant-template/ultrasound-assisted synthesis as an emerging technique with the advantages of simple reaction steps, greater control of particle size, uniform mixing, less preparation time, and less energy usage. While surfactant, sonochemistry and biomimetic route has been used for synthesizing nano-calcite and vaterite [28], the use of biosurfactant-templating strategies is still limited to brushite [29] and imogolite [30] nanotubes. In an ongoing effort, we have synthesized nano-CaCO 3 particles with diameters in the range of 10–50 nm by the solution spray process [31] [32] and used them to prepare nano-CaCO 3 /polystyrene (PS) [33] and nano-CaCO 3 /poly(methyl methacrylate) (PMMA) [34] core–shell particles, by SDS assisted atomized polymerization technique, and the isolated core–shell nanoparticles were incorporated in a polypropylene matrix [33] [35]. "
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