@article{ZaupaNeffePierceetal.2011,
  author    = {Zaupa, Alessandro and Neffe, Axel T. and Pierce, Benjamin F. and Lendlein, Andreas and Hofmann, Dieter},
  title     = {A molecular dynamic analysis of gelatin as an amorphous material Prediction of mechanical properties of gelatin systems},
  series = {The international journal of artificial organs},
  volume    = {34},
  journal   = {The international journal of artificial organs},
  number    = {2},
  publisher = {Wichtig},
  address   = {Milano},
  issn      = {0391-3988},
  doi       = {10.5301/IJAO.2010.6083},
  pages     = {139 -- 151},
  year      = {2011},
  abstract  = {Biomaterials are used in regenerative medicine for induced autoregeneration and tissue engineering. This is often challenging, however, due to difficulties in tailoring and controlling the respective material properties. Since functionalization is expected to offer better control, in this study gelatin chains were modified with physically interacting groups based on tyrosine with the aim of causing the formation of physical crosslinks. This method permits application-specific properties like swelling and better tailoring of mechanical properties. The design of the crosslink strategy was supported by molecular dynamic (MD) simulations of amorphous bulk models for gelatin and functionalized gelatins at different water contents (0.8 and 25 wt.-\%). The results permitted predictions to be formulated about the expected crosslink density and its influence on equilibrium swelling behavior and on elastic material properties. The models of pure gelatin were used to validate the strategy by comparison between simulated and experimental data such as density, backbone conformation angle distribution, and X-ray scattering spectra. A key result of the simulations was the prediction that increasing the number of aromatic functions attached to the gelatin chain leads to an increase in the number of physical netpoints observed in the simulated bulk packing models. By comparison with the Flory-Rehner model, this suggested reduced equilibrium swelling of the functionalized materials in water, a prediction that was subsequently confirmed by our experimental work. The reduction and control of the equilibrium degree of swelling in water is a key criterion for the applicability of functionalized gelatins when used, for example, as matrices for induced autoregeneration of tissues.},
  language  = {en}
}
@article{WessigPick2011,
  author    = {Wessig, Pablo and Pick, Charlotte},
  title     = {Photochemical synthesis and properties of axially chiral naphthylpyridines},
  series = {Journal of photochemistry and photobiology : A, Chemistry},
  volume    = {222},
  journal   = {Journal of photochemistry and photobiology : A, Chemistry},
  number    = {1},
  publisher = {Elsevier},
  address   = {Lausanne},
  issn      = {1010-6030},
  doi       = {10.1016/j.jphotochem.2011.06.006},
  pages     = {263 -- 265},
  year      = {2011},
  abstract  = {Five alkynyl pyridines were prepared and cyclized to naphthylpyridines as the main products in the course of a Photo-Dehydro-Diels-Alder reaction. Four of the final products are axially chiral and the determination of the rotational barrier by DFT calculations, dynamic NMR and H PLC experiments is demonstrated. (C) 2011 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{GhobadiHeuchelKratzetal.2012,
  author    = {Ghobadi, Ehsan and Heuchel, Matthias and Kratz, Karl and Lendlein, Andreas},
  title     = {Influence of different heating regimes on the shape-recovery behavior of poly(L-lactide) in simulated thermomechanical tests},
  series = {Journal of applied biomaterials \& functional materials},
  volume    = {10},
  journal   = {Journal of applied biomaterials \& functional materials},
  number    = {3},
  publisher = {Wichtig},
  address   = {Milano},
  issn      = {2280-8000},
  doi       = {10.5301/JABFM.2012.10440},
  pages     = {259 -- 264},
  year      = {2012},
  abstract  = {Aim: Multifunctional polymer-based biomaterials, which combine degradability with a shape-memory capability and in this way enable the design of actively moving implants such as self-anchoring implants or controlled release systems, have been recently introduced. Of particular interest are approved degradable polymers such as poly(L-lactide) (PLLA), which can be easily functionalized with a shape-memory effect. In the case of semicrystalline PLLA, the glass transition can be utilized as shape-memory switching domain. Methods: In this work we applied a fully atomistic molecular dynamics simulation to study the shape-memory behavior of PLLA. A heating-deformation-cooling programming procedure was applied to atomistic PLLA packing models followed by a recovery module under stress-free conditions allowing the shape recovery. The recovery was simulated by heating the samples from T-low = 250 K to T-high = 500 K with different heating rates beta of 125, 40 and 4 K.ns(-1). Results: We could demonstrate that the obtained strain recovery rate (R-r) was strongly influenced by the applied simulation time and heating rate, whereby R-r values in the range from 46\% to 63\% were achieved. On its own the application of a heating rate of 4 K.ns(-1) enabled us to determine a characteristic switching temperature of T-sw = 473 K for the modeled samples. Conclusions: We anticipate that the atomistic modeling approach presented should be capable of enabling further study of T-sw with respect to the molecular structure of the investigated SMP and therefore could be applied in the context of design and development of new shape-memory (bio) materials.},
  language  = {en}
}