ORNL develops biohybrid photoconversion system

The ORNL researchers have demonstrated and confirmed with small-angle neutron scattering analysis that light-harvesting complex II (LHC-II) proteins can self-assemble with polymers into a synthetic membrane structure and produce hydrogen.

According to a statement from the US Department of Energy lab, the researchers foresee energy-producing photoconversion systems similar to photovoltaic cells that generate hydrogen fuel, comparable to the way plants and other photosynthetic organisms convert light to energy.

‘Making a self-repairing synthetic photoconversion system is a pretty tall order,’ said ORNL researcher Hugh O’Neill. ’The ability to control structure and order in these materials for self-repair is of interest because as the system degrades it loses its effectiveness.

‘This is the first example of a protein altering the phase behaviour of a synthetic polymer that we have found in the literature. This finding could be exploited for the introduction of self-repair mechanisms in future solar-conversion systems.’

Small-angle neutron scattering analysis performed at ORNL’s High Flux Isotope Reactor (HFIR) showed that the LHC-II, when introduced into a liquid environment that contained polymers, interacted with polymers to form lamellar sheets similar to those found in natural photosynthetic membranes.

The ability of LHC-II to force the assembly of structural polymers into an ordered, layered state could enable the development of biohybrid photoconversion systems. These systems would consist of high-surface-area, light-collecting panes that use the proteins combined with a catalyst such as platinum to convert the sunlight into hydrogen, which could be used for fuel.

The research builds on previous ORNL investigations into the energy-conversion capabilities of platinised photosystem I complexes, as well as how synthetic systems based on plant biochemistry can become part of the solution to the global energy challenge.

‘We’re building on the photosynthesis research to explore the development of self-assembly in biohybrid systems,’ said O’Neill. ’The neutron studies give us direct evidence that this is occurring.’

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