@article{WestendorfNegreteBaeetal.2013,
  author    = {Westendorf, Christian and Negrete, Jose and Bae, Albert J. and Sandmann, Rabea and Bodenschatz, Eberhard and Beta, Carsten},
  title     = {Actin cytoskeleton of chemotactic amoebae operates close to the onset of oscillations},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {110},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {10},
  publisher = {National Acad. of Sciences},
  address   = {Washington},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.1216629110},
  pages     = {3853 -- 3858},
  year      = {2013},
  abstract  = {The rapid reorganization of the actin cytoskeleton in response to external stimuli is an essential property of many motile eukaryotic cells. Here, we report evidence that the actin machinery of chemotactic Dictyostelium cells operates close to an oscillatory instability. When averaging the actin response of many cells to a short pulse of the chemoattractant cAMP, we observed a transient accumulation of cortical actin reminiscent of a damped oscillation. At the single-cell level, however, the response dynamics ranged from short, strongly damped responses to slowly decaying, weakly damped oscillations. Furthermore, in a small subpopulation, we observed self-sustained oscillations in the cortical F-actin concentration. To substantiate that an oscillatory mechanism governs the actin dynamics in these cells, we systematically exposed a large number of cells to periodic pulse trains of different frequencies. Our results indicate a resonance peak at a stimulation period of around 20 s. We propose a delayed feedback model that explains our experimental findings based on a time-delay in the regulatory network of the actin system. To test the model, we performed stimulation experiments with cells that express GFP-tagged fusion proteins of Coronin and actin-interacting protein 1, as well as knockout mutants that lack Coronin and actin-interacting protein 1. These actin-binding proteins enhance the disassembly of actin filaments and thus allow us to estimate the delay time in the regulatory feedback loop. Based on this independent estimate, our model predicts an intrinsic period of 20 s, which agrees with the resonance observed in our periodic stimulation experiments.},
  language  = {en}
}
@article{HasinovicFribergKovachetal.2013,
  author    = {Hasinovic, Hida and Friberg, Stieg E. and Kovach, Ildyko and Koetz, Joachim},
  title     = {Janus emulsion drops - equilibrium calculations},
  series = {Journal of dispersion science and technology},
  volume    = {34},
  journal   = {Journal of dispersion science and technology},
  number    = {12},
  publisher = {Taylor \& Francis Group},
  address   = {Philadelphia},
  issn      = {0193-2691},
  doi       = {10.1080/01932691.2013.763728},
  pages     = {1683 -- 1689},
  year      = {2013},
  abstract  = {Experimental results indicated the contact angles in the drops of Janus emulsions formed in a one-step mixing process to be invariant within a significant range the oil volume ratios, similar to the results from microfluidics emulsification. Since this result points to a connection between the kinetically formed emulsions and the local equilibrium topology of emulsion drops, the effect of interfacial tensions on the morphology of Janus emulsions was estimated from the equilibrium interfacial tensions at the line of contact. Realistic values of the tensions revealed the limited range of these to obtain Janus drops and also offered correlation between the equilibrium entities and the curvature of the interface between the two oils.},
  language  = {en}
}
@article{VerganiCarminatiFerrarietal.2012,
  author    = {Vergani, Marco and Carminati, Marco and Ferrari, Giorgio and Landini, Ettore and Caviglia, Claudia and Heiskanen, Arto and Comminges, Clement and Zor, Kinga and Sabourin, David and Dufva, Martin and Dimaki, Maria and Raiteri, Roberto and Wollenberger, Ursula and Emneus, Jenny and Sampietro, Marco},
  title     = {Multichannel bipotentiostat integrated with a microfluidic platform for electrochemical real-time monitoring of cell cultures},
  series = {IEEE Transactions on biomedical circuits and systems},
  volume    = {6},
  journal   = {IEEE Transactions on biomedical circuits and systems},
  number    = {5},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1932-4545},
  doi       = {10.1109/TBCAS.2012.2187783},
  pages     = {498 -- 507},
  year      = {2012},
  abstract  = {An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board, compatible with arrays of microelectrodes and coupled to a microfluidic cell culture system. A versatile data acquisition software enables performing amperometry, cyclic voltammetry and impedance spectroscopy in each of the 12 independent chambers over a 100 kHz bandwidth with current resolution down to 5 pA for 100 ms measuring time. The design of the platform, its realization and experimental characterization are reported, with emphasis on the analysis of impact of input capacitance (i.e., microelectrode size) and microfluidic pump operation on current noise. Programmable sequences of successive injections of analytes (ferricyanide and dopamine) and rinsing buffer solution as well as the impedimetric continuous tracking for seven days of the proliferation of a colony of PC12 cells are successfully demonstrated.},
  language  = {en}
}