Spontaneous Assembly of Cell-Like Structures From Likely Prebiotic Materials - Problems and Prospects

Extended Abstract It has been suggested by a number of theoreticians that cellularity is a precondition for a living system. Over the years many researchers have sought to synthesize structures morphologically resembling cells under prebiotic conditions. These structures may be vesicular or contain no lipid and are perhaps best termed “cell-like structures” than “proto-cells” or “cells”. Conversely, likely prebiotic organic amphiphiles such as fatty acids only produce micelles or vesicles under select conditions: high ionic strength and divalent cations often inhibit the self-assembly of cell-like structures assembled from lipid amphiphiles such as vesicles. Hydrogen cyanide (HCN) is a ubiquitous compound in young circumstellar disks (Carr & Najita, 2008) and cometary comae (Irvine et al., 1997), and is readily produced in simulations of prebiotic atmospheric chemistry (Miller, 1957). During investigations of the chemistry of self-condensation of aqueous HCN in the presence of aldehydes we have discovered cell-like spherical and filamentous structures of extremely homogeneous size distribution which are produced robustly from these simple reactions (Figure 1). While there is some precedent for these structures (see for example Labadie et al., 1968; Kenyon & Nissenbaum, 1976), the chemical and morphological structure of these and their interactions with amphiphilic species have been investigated in considerably more detail here. These are potentially important as scaffolds for cellular development on the primitive Earth, and may have implications for life-detection on other planets and in the geological record.