posted on 2019-06-08, 00:00authored byElif S. Köksal, Susanne Liese, Ilayda Kantarci, Ragni Olsson, Andreas Carlson, Irep Gözen
Cellular compartments
are membrane-enclosed, spatially distinct
microenvironments that confine and protect biochemical reactions in
the biological cell. On the early Earth, the autonomous formation
of compartments is thought to have led to the encapsulation of nucleotides,
thereby satisfying a starting condition for the emergence of life.
Recently, surfaces have come into focus as potential platforms for
the self-assembly of prebiotic compartments, as significantly enhanced
vesicle formation was reported in the presence of solid interfaces.
The detailed mechanism of such formation at the mesoscale is still
under discussion. We report here on the spontaneous transformation
of solid-surface-adhered lipid deposits to unilamellar membrane compartments
through a straightforward sequence of topological changes, proceeding via a network of interconnected lipid nanotubes. We show
that this transformation is entirely driven by surface-free energy
minimization and does not require hydrolysis of organic molecules
or external stimuli such as electrical currents or mechanical agitation.
The vesicular structures take up and encapsulate their external environment
during formation and can subsequently separate and migrate upon exposure
to hydrodynamic flow. This may link the self-directed transition from
weakly organized bioamphiphile assemblies on solid surfaces to protocells
with secluded internal contents.