@article{NeffeLoewenbergJulichGruneretal.2021,
  author    = {Neffe, Axel T. and L{\"o}wenberg, Candy and Julich-Gruner, Konstanze K. and Behl, Marc and Lendlein, Andreas},
  title     = {Thermally-induced shape-memory behavior of degradable gelatin-based networks},
  series = {International journal of molecular sciences},
  volume    = {22},
  journal   = {International journal of molecular sciences},
  number    = {11},
  publisher = {Molecular Diversity Preservation International},
  address   = {Basel},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22115892},
  pages     = {15},
  year      = {2021},
  abstract  = {Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) alpha,omega-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27-23 kPa and Young's moduli of 215-360 kPa at 4 degrees C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 degrees C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates R-r close to 100\% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix.},
  language  = {en}
}
@article{NeffeIzraylitHommesSchattmannetal.2021,
  author    = {Neffe, Axel T. and Izraylit, Victor and Hommes-Schattmann, Paul J. and Lendlein, Andreas},
  title     = {Soft, formstable (Co)polyester blend elastomers},
  series = {Nanomaterials : open access journal},
  volume    = {11},
  journal   = {Nanomaterials : open access journal},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-4991},
  doi       = {10.3390/nano11061472},
  pages     = {18},
  year      = {2021},
  abstract  = {High crystallization rate and thermomechanical stability make polylactide stereocomplexes effective nanosized physical netpoints. Here, we address the need for soft, form-stable degradable elastomers for medical applications by designing such blends from (co)polyesters, whose mechanical properties are ruled by their nanodimensional architecture and which are applied as single components in implants. By careful controlling of the copolymer composition and sequence structure of poly[(L-lactide)-co-(epsilon-caprolactone)], it is possible to prepare hyperelastic polymer blends formed through stereocomplexation by adding poly(D-lactide) (PDLA). Low glass transition temperature T-g <= 0 degrees C of the mixed amorphous phase contributes to the low Young's modulus E. The formation of stereocomplexes is shown in DSC by melting transitions T-m > 190 degrees C and in WAXS by distinct scattering maxima at 2 theta = 12 degrees and 21 degrees. Tensile testing demonstrated that the blends are soft (E = 12-80 MPa) and show an excellent hyperelastic recovery R-rec = 66-85\% while having high elongation at break epsilon(b) up to >1000\%. These properties of the blends are attained only when the copolymer has 56-62 wt\% lactide content, a weight average molar mass >140 kg center dot mol(-1), and number average lactide sequence length >= 4.8, while the blend is formed with a content of 5-10 wt\% of PDLA. The devised strategy to identify a suitable copolymer for stereocomplexation and blend formation is transferable to further polymer systems and will support the development of thermoplastic elastomers suitable for medical applications.},
  language  = {en}
}
@article{SeckerBrosnanLuxenhoferetal.2015,
  author    = {Secker, Christian and Brosnan, Sarah M. and Luxenhofer, Robert and Schlaad, Helmut},
  title     = {Poly(alpha-Peptoid)s Revisited: Synthesis, Properties, and Use as Biomaterial},
  series = {Macromolecular bioscience},
  volume    = {15},
  journal   = {Macromolecular bioscience},
  number    = {7},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1616-5187},
  doi       = {10.1002/mabi.201500023},
  pages     = {881 -- 891},
  year      = {2015},
  abstract  = {Polypeptoids have been of great interest in the polymer science community since the early half of the last century; however, they had been basically forgotten materials until the last decades in which they have enjoyed an exciting revival. In this mini-review, we focus on the recent developments in polypeptoid chemistry, with particular focus on polymers synthesized by the ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCAs). Specifically, we will review traditional monomer synthesis (such as Leuchs, Katchalski, and Kricheldorf) and recent advances in polymerization methods to yield both linear, cyclic, and functional polymers, solution and bulk thermal properties, and preliminary results on the use of polypeptoids as biomaterials (i.e immunogenicity, biodistribution, degradability, and drug delivery).},
  language  = {en}
}