A self-catalyzed (autopoietic) synthesis of an anionic surfactant; experimental evidence and theoretical modeling

Abstract

In the last years, several different chemico-physical processes have been individuated and tested as possible instances of autopoietic machines following the original definition of Maturana & Varela (1974). Practically one deals with some autocathalitic chemical reactions during which some products are obtained, which organizes in some well individuated self-reproducing physical structures; in such a way a partition of the reaction ambient in different regions is realized. In all practical cases the partition appears as a dispersed microphase; just this last aspect makes this type of experiences an excellent candidate for mimiking the much more complicated proto- and pre-byological autopoietic systems which were (among others) the original substrates of the Maturana and Varela philosophical approach. Luisi and coworkers carried out some different processes, in which the dispersed phase is constituted by micelles, or reversed micelles (Bachmann et al., 1990, 1991, 1992); recently, liposomes begin to be a new a very stimulating subject of these researches. The present work represents a more accurate experimental study and the elaboration of a theoretical model for the autopoietic process recently reported (Bachmann et al. 1992). This paper is organized in three sections: in the first one, the criteria of autopiesis are recalled and the Luisi experimental data are reported whithout dwelling on the experimental description of the system for which one refers to the original work (Bachmann et al. 1992); in the second one, a first very simplified kinetic model is presented by which a nice agreement with the experiments can be attained, and the main assumptions on which it is based are clearly illustrated. Finally, in the third section, some more recent experimental and theoretical results are shown.