INVESTIGADORES
MOSIEWICKI mirna Alejandra
congresos y reuniones científicas
Título:
Preparation and characterization of magnetic alginate nanocomposites
Autor/es:
G.A. KLOSTER; D. MURACA; N. E. MARCOVICH; M. A. MOSIEWICKI
Lugar:
Buenos Aires
Reunión:
Congreso; COMAT2015; 2015
Resumen:
The synthesis of monodisperse nanostructures of iron oxide is currently of tremendous interest since they are extensively used in magnetic materials, as photocatalyst, sensors and medical applications such as hyperthermia, targeted drug delivery, magnetic resonance imaging, etc (Sharifi et al 2012, Zhang et al 2011, Zhou et al 2009). Below 25 nm, iron oxide nanoparticles have superparamagnetic behaviour (Hu et al, 2006). However, magnetic iron oxide nanoparticles have hydrophobic surfaces with large surface area to volume ratio. These hydrophobic interactions coupled with magnetic ones result in particle aggregation, which leads to a decrease in the magnetic properties of the agglomerated iron oxide nanoparticles respect to those of the disaggregated ones. In this sense, synthesis methods that embed nanoparticles into polymers, glass or SiO2 matrices have the added benefits of minimizing nanoparticle aggregation and forming a uniform particle dispersion with a narrow particle size distribution. In this work, sodium alginate was selected as the polymeric matrix for the preparation of magnetic films. Alginate, a natural-occurring anionic polyelectrolytic polysaccharide found in all species of brown algae and some species of bacteria, composed of α-L-guluronic (G) and α-D-mannuronic (M) units in varying proportions and sequential arrangements, and is biocompatible, biodegradable and relatively low cost (Xu et al 2006). However, pH-sensitivity of alginate could affect the characteristics of the composite films obtained: at pH below the pKa of M (3.38) and G (3.65) monomers, soluble sodium alginate is converted to insoluble alginic acid, which induces crack formation or lamination of alginate matrix, leading to low mechanical and barrier properties (Li et al, 2013).