Heads of Laboratories
Detlev W. Bronk Professor
Laboratory of Experimental Condensed Matter Physics
When considered from a broad perspective, many events that appear to occur at random, such as weather systems, are in fact part of recurring patterns and as such are subject to mathematical principles. Dr. Libchaber applies a type of mathematics called nonlinear dynamics to biological systems in order to understand how an object and its surrounding environment act on one another to provide a specific result.
Dr. Libchaber studies mathematical patterns in biology at the organismal, cellular, and molecular levels. At the organismal level, his work examines the interactions and dynamics between organism and environment, including the effects of moving boundary conditions on fluid flow. A moving fish, for example, involves a complicated interaction of a dynamic object with the surrounding fluid, with forces by both elements acting on one another. In the lab, Dr. Libchaber, in collaboration with researchers at New York University’s Courant Institute of Mathematical Sciences, studied a system of flexible filaments in a flowing soap film, which mimics a fish moving in water. Working with Escherichia coli bacteria, Dr. Libchaber has recently shown how temperature and oxygen gradients as well as bacterial concentrations finely tune and control the bacteria’s motility and genetics. The research firmly established that an organism’s environment affects its genes and behavior.
Dr. Libchaber’s lab has also undertaken a series of experiments at the single-molecule level to define the minimal conditions needed to produce an artificial cell. Within a phospholipid vesicle, which mimics a cell membrane, Dr. Libchaber places DNA containing the necessary genes and their regulatory sequences. This cell, which is in contact with a feeding solution through its semipermeable membrane, is then the environment for testing different gene networks and elementary logic circuits for their ability to reproduce essential events in a cell’s life, such as producing proteins and transporting them to the cell’s surface. The research may hold clues to the origin of life, and the ultimate aim is to produce an artificial cell that self-reproduces following a genetic program.
Another important concept concerning the origin of life is the development of a genetic code that relates the 20-amino acid world to the four-nucleotide one. Dr. Libchaber has recently shown that an RNA molecule of a stem-loop structure, acting as a ribozyme, can load an amino acid to its 3' end. This amino acid corresponds to the anticodon in the loop, and this whole process can be done without enzymes.
Past research in Dr. Libchaber’s lab has elucidated the effects of temperature on DNA. In a detailed study on the effects of thermophoresis on DNA in solution, they found that when far infrared lights are focused on the center of a chamber, DNA within the chamber moves from a hot region to a cold one. As the heat is increased, however, convection sets in and causes the opposite: The DNA collects and accumulates in the bottom center of the chamber. Because this phenomenon could be used to sustain very high concentrations of DNA or proteins, it sheds light on how critical concentrations of DNA may have been reached amid early primordial-soup chain reactions and therefore played an important role in early life forms. Then the laboratory showed that polymerase chain reaction, DNA amplification, is essentially a thermal convection process.
Bachelor’s degree in mathematics, 1956
University of Paris
Ingénieur des Télécommunications, 1958
École Nationale Supérieure des Télécommunications
M.S. in physics, 1959
University of Illinois
Ph.D. in physics, 1965
École Normale Supérieure, University of Paris
Attaché de Recherche, 1962
Maître de Recherche, 1967
Directeur de Recherche, 1974
French National Center of Scientific Research
University of Chicago
The Rockefeller University
Wolf Prize in Physics, 1986
MacArthur Fellow, 1986
Prix des Trois Physiciens, Foundation of France, 1999
National Academy of Sciences
American Academy of Arts and Sciences
French Academy of Sciences
Noireaux, V. et al. Development of an artificial cell, from self-organization to computation and self-reproduction. Proc. Natl. Acad. Sci. U.S.A. 108, 3473–3480 (2011).
Douarche, C. et al. E. coli and oxygen: A motility transition. Phys. Rev. Lett. 102, 198101 (2009).
Braun, D. and Libchaber, A. Thermal force approach to molecular evolution. Phys. Biol. 1, 1–8 (2004).
Dubertret, B. et al. In vivo imaging of quantum dots encapsulated in phospholipid micelles. Science 298, 1759–1762 (2002).
Zhang, J. et al. Flexible filaments in a flowing soap film as a model for one-dimensional flags in a two-dimensional wind. Nature 408, 835–839 (2000).