Mary's work featured in the HFSP annual review

(text extracted from the HFSP annual review)

Exploring bacterial solar panels as an energy supply of the future

Biophotovoltaic (BPV) technology uses biofilms of photosynthetic bacteria grown onto electrode surfaces to harvest solar energy – a kind of bacteria-based solar panel. However, such devices are currently limited by unexpectedly slow electron transfer between the bacteria and the electrode, and this interface remains poorly understood. It is unclear even which species are responsible for this crucial electron-transfer process.

My project aims to use a combination of several sophisticated and highly specialised surface-study techniques alongside bioelectrochemistry, synthetic biology and electrode design to study the key species (including redox proteins and mediator complexes) at this interface, both individually and in situ within model lipid bilayers and finally within the biofilms themselves. The techniques I use include neutron reflectometry, which allows in situ structural characterisation of buried interfaces with an angstrom-level resolution, sum-frequency generation (SFG) spectroscopy, a very powerful surface-specific infrared technique that provides a wealth of information about the chemical nature of the interfacial species, electrochemical Raman spectroscopy and various other complementary methods. Importantly, these will allow us to build up a mechanistic picture of each aspect of these complex buried biointerfaces and hence distinguish between different electron-transfer mechanisms (e.g. via pili aromatic amino acids, outer-membrane redox proteins or diffusional shuttles) that are currently proposed.