SYNTHESIS OF MICRO-COMPOSITE BEADS WITH MAGNETIC NANO-PARTICLES EMBEDDED IN POROUS CaCO3 MATRIX

SINTEZA MIKROKOMPOZITNIH KROGLIC Z MAGNETNIMI NANODELCI V POROZNI MATRIKI CaCO3

Alenka Vesel1, Aljoša Košak2, David Haložan3, Kristina Eleršič1

1Department F4, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
2University of Maribor, Faculty of mechanical engineering, Smetanova 17, 2000 Maribor, Slovenia
3Institute of Physical Biology, Toplarniška 19, 1000 Ljubljana, Slovenia

[email protected]

Prejem rokopisa – received: 2011-05-20; sprejem za objavo – accepted for publication: 2011-07-22

A method for synthesis of soft magnetic microbeads is presented. The microbeads are made from magnetic nanoparticles dispersed in CaCO3 (calcium carbonate) matrix. The composite beads are almost perfectly spherical with a diameter of few micrometers. The majority of the composite beads consists of a porous CaCO3 matrix. Magnetic nanoparticles with a size of about 10-15 nm are made of Fe2O3. They are captured inside the pores of CaCO3 matrix during its formation. CaCO3 matrix is formed by crystallization from saturated solution of sodium carbonate and calcium chloride. The composite beads are coated with a layer of functionalized polymer. The magnetic microbeads were characterized by SEM and XPS. Different functional groups were detected by XPS measurements including SO3–, NH3+, NH2, CO32– and OH groups. The results indicate that the iron oxide particles are absent on the surface and that the polymer coating serves as a good biocompatible film.

Keywords: composite, surface characterization, XPS, functionalization, Fe nanoparticles, microbeads

V tem prispevku predstavljamo metodo za sintezo delcev, ki so sestavljeni iz kompozita magnetnih nanodelcev v matrici iz kalcijevega karbonata (CaCO3). Velikost kompozitnih delcev, ki so popolnoma sferične oblike, je nekaj mikrometrov. Ključni del ogrodja kompozitnega delca sestavlja zelo porozna matrica CaCO3. Magnetni nanodelci velikosti približno 10-15 nm so narejeni iz Fe2O3. Ti nanodelci se med tvorjenjem matrice CaCO3 ujamejo v notranjost por. CaCO3 matrica se tvori pri kristalizaciji nasičene raztopine natrijevega karbonata in kalcijevega klorida. Tako nastali kompozit je nato oplaščen še s plastjo funkcionaliziranega polimera. Sintetizirane magnetne kompozitne delce smo analizirali z metodama SEM in XPS. Kot je razvidno iz XPS meritev, je prišlo na površini do nastanka različnih funkcionalnih skupin kot so SO3–, NH3+, NH2, CO32– in OH skupine. Rezultati dokazujejo, da na površini mikrodelcev ne najdemo nanodelcev, ki so skriti znotraj por, ter da lahko polimerna prevleka, ki prekriva mikrodelce, služi kot dobra biokompatibilna podlaga za nadaljnjo vezavo bioloških substanc.

Ključne besede: kompozit, površinska karakterizacija, XPS, funkcionalizacija, Fe nanodelci, mikrokroglice