Atmospheric Aerosols and Water-Air Interfaces in Prebiotic Chemistry
Models of the origin of life assume that the chemical monomeric precursors (amino acids, lipids, sugars, purine and pyrimidine bases, phosphates) for biopolymers existed on Earth. These could be chemically synthesized endogenously or generated exogenously and transported to Earth by meteoric or cometary infall. Although laboratory simulation of some of these processes has had success in producing organic monomers, there has been limited success in producing populations of replicating biopolymers. Chemistry and self assembly provides the bottleneck in the transition between the diversity of small molecules (“prebiotic soup”) and complex, self-replicating organisms.
Films at the water-air interface, characteristic of oceans and atmospheric aerosols, are implicated in the conversion of small molecules found in the “prebiotic soup” into more complex biomolecules necessary in the production of living organisms. These films act as “reactors” in which water-eliminating reactions, like those necessary in the production of peptides and nucleic acids, are favorable. The anhydrous nature of surfactant films provides favorable initial conditions for achieving such polymerization reactions. Our experimental approach will involve the use of Langmuir-Blodgett troughs, Fourier-Transform spectroscopy, and cavity ring down spectroscopy as well as the construction of an aerosol reactor, to explore the chemical activity at these interfaces, interfacial transport between the atmosphere and aerosol phase, and the ability of surface reactions to induce morphological changes to aqueous aerosol particles.