@article{HahnLuxenhoferHeltenetal.2021,
  author    = {Hahn, Lukas and Luxenhofer, Robert and Helten, Holger and Forster, Stefan and Fritze, Lars and Polzin, Lando and Keßler, Larissa},
  title     = {ABA Type Amphiphiles with Poly(2-benzhydryl-2-oxazine) Moieties: Synthesis, Characterization and Inverse Thermogelation},
  series = {Macromolecular Chemistry and Physics},
  volume    = {222},
  journal   = {Macromolecular Chemistry and Physics},
  number    = {17},
  doi       = {10.1002/macp.202100114},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265124},
  year      = {2021},
  abstract  = {Thermoresponsive polymers are frequently involved in the development of materials for various applications. Here, polymers containing poly(2- benzhydryl-2-oxazine) (pBhOzi) repeating units are described for the first time. The homopolymer pBhOzi and an ABA type amphiphile comprising two flanking hydrophilic A blocks of poly(2-methyl-2-oxazoline) (pMeOx) and the hydrophobic aromatic pBhOzi central B block (pMeOx-b-pBhOzi-b-pMeOx) are synthesized and the latter is shown to exhibit inverse thermogelling properties at concentrations of 20 wt.\% in water. This behavior stands in contrast to a homologue ABA amphiphile consisting of a central poly(2-benzhydryl-2-oxazoline) block (pMeOx-b-pBhOx-b-pMeOx). No inverse thermogelling is observed with this polymer even at 25 wt.\%. For 25 wt.\% pMeOx-b-pBhOzi-b-pMeOx, a surprisingly high storage modulus of ≈22 kPa and high values for the yield and flow points of 480 Pa and 1.3 kPa are obtained. Exceeding the yield point, pronounced shear thinning is observed. Interestingly, only little difference between self-assemblies of pMeOx-b-pBhOzi-b-pMeOx and pMeOx-b-pBhOx-b-pMeOx is observed by dynamic light scattering while transmission electron microscopy images suggest that the micelles of pMeOx-b-pBhOzi-b-pMeOx interact through their hydrophilic coronas, which is probably decisive for the gel formation. Overall, this study introduces new building blocks for poly(2-oxazoline) and poly(2-oxazine)-based self-assemblies, but additional studies will be needed to unravel the exact mechanism.},
  language  = {en}
}
@article{LuebtowLorsonFingeretal.2020,
  author    = {L{\"u}btow, Michael M. and Lorson, Thomas and Finger, Tamara and Gr{\"o}ber-Becker, Florian-Kai and Luxenhofer, Robert},
  title     = {Combining Ultra-High Drug-Loaded Micelles and Injectable Hydrogel Drug Depots for Prolonged Drug Release},
  series = {Macromolecular Chemistry and Physics},
  volume    = {221},
  journal   = {Macromolecular Chemistry and Physics},
  number    = {1},
  doi       = {10.1002/macp.201900341},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208115},
  pages     = {1900341},
  year      = {2020},
  abstract  = {Hydrogel-based drug depot formulations are of great interest for therapeutic applications. While the biological activity of such drug depots is often characterized well, the influence of incorporated drug or drug-loaded micelles on the gelation properties of the hydrogel matrix is less investigated. However, the latter is of great importance from fundamental and application points of view as it informs on the physicochemical interactions of drugs and water-swollen polymer networks and it determines injectability, depot stability, as well as drug-release kinetics. Here, the impact of incorporated drug, neat polymer micelles, and drug-loaded micelles on the viscoelastic properties of a cytocompatible hydrogel is investigated systematically. To challenge the hydrogel with regard to the desired application as injectable drug depot, curcumin (CUR) is chosen as a model compound due to its very low-water solubility and limited stability. CUR is either directly solubilized by the hydrogel or pre-incorporated into polymer micelles. Interference of CUR with the temperature-induced gelation process can be suppressed by pre-incorporation into polymer micelles forming a binary drug delivery system. Drug release from a collagen matrix is studied in a trans-well setup. Compared to direct injection of drug formulations, the hydrogel-based systems show improved and extended drug release over 10 weeks.},
  language  = {en}
}
@article{LuebtowMarciniakSchmiedeletal.2019,
  author    = {L{\"u}btow, Michael M. and Marciniak, Henning and Schmiedel, Alexander and Roos, Markus and Lambert, Christoph and Luxenhofer, Robert},
  title     = {Ultra-high to ultra-low drug loaded micelles: Probing host-guest interactions by fluorescence spectroscopy},
  series = {Chemistry - A European Journal},
  volume    = {25},
  journal   = {Chemistry - A European Journal},
  number    = {54},
  doi       = {10.1002/chem.201902619},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206128},
  pages     = {12601-12610},
  year      = {2019},
  abstract  = {Polymer micelles are an attractive means to solubilize water insoluble compounds such as drugs. Drug loading, formulations stability and control over drug release are crucial factors for drug-loaded polymer micelles. The interactions between the polymeric host and the guest molecules are considered critical to control these factors but typically barely understood. Here, we compare two isomeric polymer micelles, one of which enables ultra-high curcumin loading exceeding 50 wt.\%, while the other allows a drug loading of only 25 wt.\%. In the low capacity micelles, steady-state fluorescence revealed a very unusual feature of curcumin fluorescence, a high energy emission at 510 nm. Time-resolved fluorescence upconversion showed that the fluorescence life time of the corresponding species is too short in the high-capacity micelles, preventing an observable emission in steady-state. Therefore, contrary to common perception, stronger interactions between host and guest can be detrimental to the drug loading in polymer micelles.},
  subject      = {Polymer-drug interaction},
  language  = {en}
}