by Keyword: Surfactant

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Ramos, E., Pardo, W. A., Mir, M., Samitier, J., (2017). Dependence of carbon nanotubes dispersion kinetics on surfactants Nanotechnology 28, (13), 135702

Carbon nanotubes (CNTs) have been the subject of many studies due to their unique structure and desirable properties. However, the ability to solubilize and separate single CNTs from the bundles they form is still a challenge that needs to be overcome in order to extend their applications in the field of Nanotechnology. Covalent interactions are designed to modify CNTs surface and so prevent agglomeration. Though, this method alters the structures and intrinsic properties of CNTs. In the present work, noncovalent approaches to functionalize and solubilize CNTs are studied in detail. A dispersion kinetic study was performed to characterize the ability of different type of surfactants (non-ionic, anionic, cationic and biopolymer) to unzip CNT bundles. The dispersion kinetic study performed depicts the distinct CNTs bundles unzipping behavior of the different type of surfactants and the results elucidate specific wavelengths in relation with the degree of CNT clustering, which provides new tools for a deeper understanding and characterization of CNTs. Small angle x-ray scattering and transmission electron microscopy results are in agreement with UV-vis-NIR observations, revealing perfectly monodispersed CNTs for the biopolymer and cationic surfactant.

Keywords: Dispersion, DNA, Single-walled carbon nanotubes (SWCNTs), Small angle x-ray scattering (SAXS), Sodium dodecyl sulfate (SDS), Surfactant, Triton X-100

Montufar, E. B., Traykova, T., Gil, C., Harr, I., Almirall, A., Aguirre, A., Engel, E., Planell, J. A., Ginebra, M. P., (2010). Foamed surfactant solution as a template for self-setting injectable hydroxyapatite scaffolds for bone regeneration Acta Biomaterialia 6, (3), 876-885

The application of minimally invasive surgical techniques in the field of orthopaedic surgery has created a growing need for new injectable synthetic materials that can be used for bone grafting In this work a novel fully synthetic injectable calcium phosphate foam was developed by mixing alpha-tricalcium phosphate (alpha-TCP) powder with a foamed polysorbate 80 solution Polysorbate 80 is a non-ionic surfactant approved for parenteral applications The foam was able to retain the porous structure after injection provided that the foamed paste was injected shortly after mixing (typically 2 5 min), and set through the hydrolysis of alpha-TCP to a calcium-deficient hydroxyapatite, thus producing a hydroxyapatite solid foam in situ The effect of different processing parameters on the porosity. microstructure, injectability and mechanical properties of the hydroxyapatite foams was analysed, and the ability of the pre-set foam to support osteoblastic-like cell proliferation and differentiation was assessed. Interestingly, the concentration of surfactant needed to obtain the foams was lower than that considered safe in drug formulations for parenteral administration The possibility of combining bioactivity, injectability, macroporosity and self-setting ability in a single fully synthetic material represents a step forward in the design of new materials for bone regeneration compatible with minimally invasive surgical techniques.

Keywords: Calcium phosphate cement, Hydroxyapatite foam, Scaffold, Surfactant, Injectable material

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