@article{CherstvyNagelBetaetal.2018,
  author    = {Cherstvy, Andrey G. and Nagel, Oliver and Beta, Carsten and Metzler, Ralf},
  title     = {Non-Gaussianity, population heterogeneity, and transient superdiffusion in the spreading dynamics of amoeboid cells},
  series = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  volume    = {20},
  journal   = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  number    = {35},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/c8cp04254c},
  pages     = {23034 -- 23054},
  year      = {2018},
  abstract  = {What is the underlying diffusion process governing the spreading dynamics and search strategies employed by amoeboid cells? Based on the statistical analysis of experimental single-cell tracking data of the two-dimensional motion of the Dictyostelium discoideum amoeboid cells, we quantify their diffusive behaviour based on a number of standard and complementary statistical indicators. We compute the ensemble- and time-averaged mean-squared displacements (MSDs) of the diffusing amoebae cells and observe a pronounced spread of short-time diffusion coefficients and anomalous MSD-scaling exponents for individual cells. The distribution functions of the cell displacements, the long-tailed distribution of instantaneous speeds, and the velocity autocorrelations are also computed. In particular, we observe a systematic superdiffusive short-time behaviour for the ensemble- and time-averaged MSDs of the amoeboid cells. Also, a clear anti-correlation of scaling exponents and generalised diffusivity values for different cells is detected. Most significantly, we demonstrate that the distribution function of the cell displacements has a strongly non-Gaussian shape andusing a rescaled spatio-temporal variablethe cell-displacement data collapse onto a universal master curve. The current analysis of single-cell motions can be implemented for quantifying diffusive behaviours in other living-matter systems, in particular, when effects of active transport, non-Gaussian displacements, and heterogeneity of the population are involved in the dynamics.},
  language  = {en}
}
@misc{NiedlBerensteinBeta2016,
  author    = {Niedl, Robert Raimund and Berenstein, Igal and Beta, Carsten},
  title     = {How imperfect mixing and differential diffusion accelerate the rate of nonlinear reactions in microfluidic channels},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95810},
  pages     = {6451 -- 6457},
  year      = {2016},
  abstract  = {In this paper, we show experimentally that inside a microfluidic device, where the reactants are segregated, the reaction rate of an autocatalytic clock reaction is accelerated in comparison to the case where all the reactants are well mixed. We also find that, when mixing is enhanced inside the microfluidic device by introducing obstacles into the flow, the clock reaction becomes slower in comparison to the device where mixing is less efficient. Based on numerical simulations, we show that this effect can be explained by the interplay of nonlinear reaction kinetics (cubic autocatalysis) and differential diffusion, where the autocatalytic species diffuses slower than the substrate.},
  language  = {en}
}
@article{NiedlBerensteinBeta2016,
  author    = {Niedl, Robert Raimund and Berenstein, Igal and Beta, Carsten},
  title     = {How imperfect mixing and differential diffusion accelerate the rate of nonlinear reactions in microfluidic channels},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  volume    = {18},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/c6cp00224b},
  pages     = {6451 -- 6457},
  year      = {2016},
  abstract  = {In this paper, we show experimentally that inside a microfluidic device, where the reactants are segregated, the reaction rate of an autocatalytic clock reaction is accelerated in comparison to the case where all the reactants are well mixed. We also find that, when mixing is enhanced inside the microfluidic device by introducing obstacles into the flow, the clock reaction becomes slower in comparison to the device where mixing is less efficient. Based on numerical simulations, we show that this effect can be explained by the interplay of nonlinear reaction kinetics (cubic autocatalysis) and differential diffusion, where the autocatalytic species diffuses slower than the substrate.},
  language  = {en}
}
@misc{NiedlBeta2015,
  author    = {Niedl, Robert Raimund and Beta, Carsten},
  title     = {Hydrogel-driven paper-based microfluidics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81083},
  pages     = {2452 -- 2459},
  year      = {2015},
  abstract  = {Paper-based microfluidics provide an inexpensive, easy to use technology for point-of-care diagnostics in developing countries. Here, we combine paper-based microfluidic devices with responsive hydrogels to add an entire new class of functions to these versatile low-cost fluidic systems. The hydrogels serve as fluid reservoirs. In response to an external stimulus, e.g. an increase in temperature, the hydrogels collapse and release fluid into the structured paper substrate. In this way, chemicals that are either stored on the paper substrate or inside the hydrogel pads can be dissolved, premixed, and brought to reaction to fulfill specific analytic tasks. We demonstrate that multi-step sequences of chemical reactions can be implemented in a paper-based system and operated without the need for external precision pumps. We exemplify this technology by integrating an antibody-based E. coli test on a small and easy to use paper device.},
  language  = {en}
}
@article{NiedlBeta2015,
  author    = {Niedl, Robert Raimund and Beta, Carsten},
  title     = {Hydrogel-driven paper-based microfluidics},
  series = {LAB on a chip : miniaturisation for chemistry and biology},
  volume    = {11},
  journal   = {LAB on a chip : miniaturisation for chemistry and biology},
  number    = {15},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1473-0197},
  doi       = {10.1039/c5lc00276a},
  pages     = {2452 -- 2459},
  year      = {2015},
  abstract  = {Paper-based microfluidics provide an inexpensive, easy to use technology for point-of-care diagnostics in developing countries. Here, we combine paper-based microfluidic devices with responsive hydrogels to add an entire new class of functions to these versatile low-cost fluidic systems. The hydrogels serve as fluid reservoirs. In response to an external stimulus, e.g. an increase in temperature, the hydrogels collapse and release fluid into the structured paper substrate. In this way, chemicals that are either stored on the paper substrate or inside the hydrogel pads can be dissolved, premixed, and brought to reaction to fulfill specific analytic tasks. We demonstrate that multi-step sequences of chemical reactions can be implemented in a paper-based system and operated without the need for external precision pumps. We exemplify this technology by integrating an antibody-based E. coli test on a small and easy to use paper device.},
  language  = {en}
}