Adv Polym Sci (2013) 262: 415–430
DOI: 10.1007/12_2013_268
© Springer-Verlag Berlin Heidelberg 2013
Published online: 16 November 2013
Stimuli-Sensitive Microgels from Native
Elastin: An Easy Approach for a Drug
Release System
Smriti Singh, Fuat Topuz, Krystyna Albrecht, Ju ¨ rgen Groll,
and Martin Mo ¨ller
Abstract Thermo- and pH-responsive microgels were prepared from solubilized
native elastin by crosslinking of the elastin lysine residues with poly(ethylene
glycol) diglycidyl ether (PEG-DGE) and with bis(sulfosuccinimidyl) suberate
(BS3). In the first case, a peptide-PEG conetwork was obtained whereas, in the
second case, the elastin peptides were interlinked with hydrophobic bridges. The
structure of the microgels was controlled by the ratio of crosslinker to elastin and
by performing the crosslinking reaction in an inverse minielemulsion, yielding
particles with a diameter in the submicron range. Depending on the degree of
crosslinking, the hybrid microgels exhibited a volume change transition at 37 and
35.5
C and pH responsivity in the range of 5–7 for microgels crosslinked with
PEG-DE and BS3, respectively. This temperature- and pH-responsive behavior
can be assigned to the well-investigated coacervation of elastin peptides, demonstrating that the elastin functionality is abolished only by rather dense crosslinking.
In spite of the broad distribution in the molecular weight of the elastin molecules,
the microgels remained soluble. Light scattering and sedimentation experiments
demonstrated that the coacervation occurred predominantly intramolecularly,
i.e., by collapse in the core while the corona stabilized the colloidal dispersion
against precipitation. Preliminary experiments were conducted to evaluate the
suitability of these microgels for use as a drug-release system and demonstrated
S. Singh, F. Topuz, and M. Mo ¨ller (*)
DWI-Interactive Materials Research and Institute of Technical and Macromolecular
Chemistry, RWTH Aachen University, Forckenbeckstrasse 50, 52056 Aachen, Germany
e-mail: moeller@dwi.rwth-aachen.de
K. Albrecht and J. Groll
DWI-Interactive Materials Research and Institute of Technical and Macromolecular
Chemistry, RWTH Aachen University, Forckenbeckstrasse 50, 52056 Aachen, Germany
Department and Chair of Functional Materials in Medicine and Dentistry, University Hospital
Wu ¨rzburg, Pleicherwall 2, 97070 Wu ¨rzburg, Germany
DOI: 10.1007/12_2013_268
© Springer-Verlag Berlin Heidelberg 2013
Published online: 16 November 2013
Stimuli-Sensitive Microgels from Native
Elastin: An Easy Approach for a Drug
Release System
Smriti Singh, Fuat Topuz, Krystyna Albrecht, Ju ¨ rgen Groll,
and Martin Mo ¨ller
Abstract Thermo- and pH-responsive microgels were prepared from solubilized
native elastin by crosslinking of the elastin lysine residues with poly(ethylene
glycol) diglycidyl ether (PEG-DGE) and with bis(sulfosuccinimidyl) suberate
(BS3). In the first case, a peptide-PEG conetwork was obtained whereas, in the
second case, the elastin peptides were interlinked with hydrophobic bridges. The
structure of the microgels was controlled by the ratio of crosslinker to elastin and
by performing the crosslinking reaction in an inverse minielemulsion, yielding
particles with a diameter in the submicron range. Depending on the degree of
crosslinking, the hybrid microgels exhibited a volume change transition at 37 and
35.5
C and pH responsivity in the range of 5–7 for microgels crosslinked with
PEG-DE and BS3, respectively. This temperature- and pH-responsive behavior
can be assigned to the well-investigated coacervation of elastin peptides, demonstrating that the elastin functionality is abolished only by rather dense crosslinking.
In spite of the broad distribution in the molecular weight of the elastin molecules,
the microgels remained soluble. Light scattering and sedimentation experiments
demonstrated that the coacervation occurred predominantly intramolecularly,
i.e., by collapse in the core while the corona stabilized the colloidal dispersion
against precipitation. Preliminary experiments were conducted to evaluate the
suitability of these microgels for use as a drug-release system and demonstrated
S. Singh, F. Topuz, and M. Mo ¨ller (*)
DWI-Interactive Materials Research and Institute of Technical and Macromolecular
Chemistry, RWTH Aachen University, Forckenbeckstrasse 50, 52056 Aachen, Germany
e-mail: moeller@dwi.rwth-aachen.de
K. Albrecht and J. Groll
DWI-Interactive Materials Research and Institute of Technical and Macromolecular
Chemistry, RWTH Aachen University, Forckenbeckstrasse 50, 52056 Aachen, Germany
Department and Chair of Functional Materials in Medicine and Dentistry, University Hospital
Wu ¨rzburg, Pleicherwall 2, 97070 Wu ¨rzburg, Germany