(741e) Synthesis and Characterisation of Hollow Composite Magnetite/Silica Microparticles for Drug Delivery Systems

Synthesis and characterisation of hollow composite magnetite/silica
microparticles for drug delivery systems

Kovacik Pavel, Stepanek
Frantisek

ICT
Prague, Department of
Chemical Engineering, Laboratory of Chemical Robotics

kovacikp@vscht.cz

The aim of this work is to prepare hollow composite
magnetite/silica microparticles in the size range of tens of micrometers via
soft templating route. The microparticles have a porous silica (SiO₂)
shell in which nanoparticles of magnetite (Fe₃O₄) are
dispersed (Figure 1). As a silica source is used tetraethyl orthosilicate
(TEOS) and as a liquid template octylamine (OA). Magnetite nanoparticles used
for this work were prepared by the co-precipitation method and stabilized with
oleic acid. This modification evokes their hydrophobicity and ensures that they
are dispersible in the organic template phase (OA). After removal of the
template the magnetite nanoparticles are either in the silica shell or inside
the hollow core. Such prepared microparticles can be useful in systems for
target delivery.

Figure  SEQ Figure \* ARABIC 1: Scheme of preparation of hollow composite
magnetite/silica microparticles with a porous shell via soft templating route.

We will show that particle size can be systematically
varied in the range of 1-50 µm and that the composite microparticles are
able to heat up in presence of an external alternating magnetic field. The
particle size distribution was measured by the laser scattering method,
external alternating magnetic field was created by PowerCube 32/400 at 400 kHz
and the temperature rise was recorded with time. The microstructure of the
porous microparticles was visualized by SEM and confocal microscopy. The
permeability of the silica shell was characterised indirectly by measuring the
uptake/release kinetics of octylamine (marked by nile red dye) using UV/VIS
spectrophotometry.