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(319a) Core-Shell Structured Composite Microparticles With Ability to Store a Chemical Payload and Release a Defined Quantity „On Demand“

Kovacik, P., Prague Institute of Chemical Technology
Stepanek, F., University of Chemistry and Technology

Core-shell structured composite microparticles with
ability to store a chemical payload and release a defined quantity ?on demand?

P. Kovacik,
M. Singh, F.Stepanek

ICT Prague, Laboratory of chemical
robotics, Technicka 5, 166 28 Prague,  

Tel.: 2 2044 3046, e-mail: kovacikp@vscht.cz

The aim of this work was the
preparation of biocompatible microparticles with a hollow interrior. The
microparticles must be able to encapsulate
and store a chemical payload for a certain time, followed by the release on
demand of this payload. In our previous work [1] we have prepared silica
microparticles with a hollow core and found that the diffusion across the
mesoporous silica shell was strongly dependent on
temperature. In this work, we used this dependence and attached iron oxide
nanoparticles on the surface of the silica shell to create composite iron
oxide/silica microparticles. The iron oxide nanoparticles were able to heat up in the presence
of an alternating magnetic field. This property allowed us to use magnetic
field as a tool for remote control of diffusion across the microparticle shell. To avoid spontaneous leakage of
encapsulated payload in time, we have modified the surface of the composite
microparticles with a layer
of palm oil. Palm oil is a phase change material which is solid under 37 °C.
We showed that the resultant composite microparticles are able to store a
payload for several months and release a defined quantity on demand by the
application of a magnetic field. The particles were characterised in shape,
size, heating ability and their mass transport properties.

[1] Kovacik P., Kremlackova Z., Stepanek F., ?Investigation of radiofrequency induced
release kinetics from magnetic hollow silica microspheres?, Micropor.
Mesopor. Mater. 159, 119-125 (2012)