Living Crystals of Light-Activated Colloidal Surfers

• Autores: Jeremie Palacci, Stefano Sacanna, Asher Preska Steinberg
• Localización: Science, ISSN 0036-8075, Vol. 339, Nº 6122, 2013, págs. 937-940
• Idioma: inglés
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• Resumen

  • Spontaneous formation of colonies of bacteria or flocks of birds are examples of self-organization in active living matter. Here, we demonstrate a form of self-organization from nonequilibrium driving forces in a suspension of synthetic photoactivated colloidal particles. They lead to two-dimensional "living crystals," which form, break, explode, and re-form elsewhere. The dynamic assembly results from a competition between self-propulsion of particles and an attractive interaction induced respectively by osmotic and phoretic effects and activated by light. We measured a transition from normal to giant-number fluctuations. Our experiments are quantitatively described by simple numerical simulations. We show that the existence of the living crystals is intrinsically related to the out-of-equilibrium collisions of the self-propelled particles.