Fluid self-organized machines

Systems far from thermodynamic equilibrium are discussed, e.g. lasers, amoeboid cells, cell clusters, etc. Different types of instabilities are described by rate equations. The ordered state is produced out of a uniform state and a self-organized machine is obtained. The spatial-temporal pattern of an interfacial instability can be used to build a fluid self-organized automobile (transporter). The temporal pattern makes the machine cycle while the spatial pattern produces the spatial spread machine. The spatial movement of droplets can be directed by using light-sensitive molecules like spiropyran in the interface. The organization of amoeboid cells is discussed. The signal transduction chain of amoeboid migrating cells is approximated; the plasma membrane is the essential element. The membrane contains (i) a detection unit for registering extracellular signals and (ii) a chemical amplifier. The second intracellular signal created performs several functions: (i) the activation of the microfilaments, (ii) the activation of the adhesion proteins and (iii) the renewal of the detection unit. The processes are described by rate equations and the machine equation is extracted. Only the diffusion of the small sized molecules of the second intracellular signal are considered. The theoretical predictions are compared with experimental results: (i) an inactivated cellular state is predicted for low pumping; (ii) an isotropic state for higher pumping (cell adhesion but no migration); (iii) a polar activated cellular stale for even higher pumping (adhesion and directed migration); (iv) a bipolar activated cellular state for even higher pumping (cell elongation and orientation). The machine characteristics of the different activated states are discussed: (i) the monopole moment of the loaded receptors is the signal for the speed; (ii) the dipole moment of the receptor distribution in respect to the long axis of the cell is used as feedback signal in the automatic controller responsible for the angle of migration; (iii) the quadrupole moment of the receptor distribution is responsible for cell elongation and orientation. The model predictions are verified for different amoeboid cells, e.g. granulocytes, monocytes, melanocytes, fibroblasts, osteoblasts, neural crest cells, etc. Interacting cells have the ability to form ordered structures. A polar and apolar nematic liquid crystal phase is predicted and actually verified.