1 research outputs found
Formation and Characterization of Light-Responsive TEMPO-Oxidized Konjac Glucomannan Microspheres
A light-responsive delivery system
has been developed. It consists
of gelly microÂspheres made of TEMPO-oxidized Konjac glucoÂmannan
(OKGM) polymers where the carboxyl (COO<sup>–</sup>) groups
are cross-linked via ferric ions (Fe<sup>3+</sup>) and in which functional
ingredients may be incorporated. By irradiation with (simulated) sunlight,
the microspheres degrade, thereby releasing the encapsulated component(s).
The degree of oxidation (DO) of the OKGM polymers could be well-controlled
between 15 and 80%, as confirmed by proton titrations and FT-IR spectroscopy.
OKGM of DO 80% was selected to prepare the microspheres because the
high COO<sup>–</sup> content leads to a high density of cross-links,
yielding a strong gel. The electroÂkinetic potential of the OKGM
particles increases with increasing pH and decreasing salt concentration.
Mössbauer and FT-IR spectroscopy revealed that the cross-links
are formed through two modes of COO<sup>–</sup>–Fe<sup>3+</sup> coordination, that is, 68.4% by bridging and 31.6% by unidentate
binding. Thus, the unique properties of the OKGM microspheres make
them potentially applicable as light-controlled biocompatible delivery
systems