Does the World Need a Global Artificial Synthesis Project?
January 2, 2011 4 Comments
Many exciting areas of nanotechnology research are converging on artificial photosynthesis. The connection between the health of our plant and the humans it sustains is now part of a growing field termed ‘planetary medicine.’ Would a macroscience Global Artificial Photosynthesis (GAP) Project tackling critical global energy, water and food problems be a definitive endeavour in planetary nanomedicine? If so, how should it be initiated or organised?
Professor Tom Faunce’s research seeks to expand upon his ideas for a Global Artificial Photosynthesis (GAP) Project as a defining endeavour of planetary nanomedicine. At the Copenhagen Climate Conference in December 2009, the world’s nation states, created the Copenhagen Accord. This non-binding political agreement recognized the critical impacts of population growth and fossil fuel-driven climate change as wellas the need to establish a comprehensive adaptation program including international support for those countries most vulnerable to its adverse effects. For the first time, all major emitting countries agreed to a target of keeping global warming to less than 2°C above pre-industrial levels.
The United Nations Millennium Development Goals are particularly focused on related issues of energy storage, production and conversion, agricultural productivity enhancement, water treatment and remediation and experts have encouraged nanotechnology to systematically contribute to their achievement. These critical survival issues forthe poor will be exacerbated as global population grows towards 10 billion by 2050 and energy consumption rises from 13.5 TW to ˜40.8 TW. Artificial photosynthesis (AP) involves an exciting convergence of nanotechnology research on such problems. Would a ‘big science’ approach to AP represent a defining exercise in planetary nanomedicine?
Photosynthetic organisms absorb photons from various regions of the solar spectrum into “antenna”chlorophyll molecules in cell membrane thylakoids, plants do the same in intracellular organelles called chloroplasts. The absorbed photons’ energy is used by the oxygen-evolving complex (OEC) in a protein known as photo system II to oxidize water (H2O) to oxygen (O2) which is released to the atmosphere. The electrons there by produced are captured in chemical bonds by photosystem Ito reduce NADP (nicotinamide adenine dinucleotide phosphate) for storage in ATP (adenosine triphosphate) and NADPH (nature’s form of hydrogen). In the “dark reaction” ATP and NADPH as well as carbon dioxide (CO2) are used in the Calvin-Benson cycle to make food in the form of carbohydrate via the enzyme Rubisco. Photosynthesis, the ultimate source of our oxygen, food and fossil fuels, already traps ˜100 TW of 150,000 TW solar energy striking the earth. Nanoscience researchers are actively redesigning photosynthesis to achieve, for example, low cost, localised, conversion of sunlight and dirty water into fuel for heating and cooking. Enhanced AP, if applied equitably, could assist crop production on marginal lands, reduce atmospheric CO2levels, lower geopolitical and military tensions over fossil fuel, food and water scarcity and create hydrogen for industrial storage.
AP is driven by nanotechnology advances intersecting with multiple scientific disciplines. Examples include water oxidation systems utilizing photosensitive components grafted by core-shell nanowires to a genetically engineered virus. Two-dimensional Fourier transform electronic spectroscopy enhancement has shown that photosynthetic electron pathways are essentially performing a single quantum computation, sensing many states simultaneously suggesting a mechanism for enhancing the efficiency of the energy transfer of quantum dots’ light harvesting capabilities by quantum coherence mechanisms, mesoporous thin film dye-sensitive solar cells of semiconductor nanoparticles and carbon nanotubes harvesting and conducting the resultant electricity. An inexpensive (non rare-metal) water catalytic system has been tested which is self-repairing and allegedly operates under ambient conditions at neutral pH with non-pure water. Synthetic proteins (maquettes) have been created to allow testing of engineering principles for artificial photosystems and reaction centers.
Numerous competitively funded nanotechnology-focused AP research teams already exist in many developed nations. A dozen European research partners form the Solar-H AP network, supported by the European Union. The US Dept. of Energy (DOE)Joint Center for Artificial Photosynthesis(JCAP) led by the California Institute of Technology (Caltech) and Lawrence Berkeley National Laboratory has US $122m over 5 years to build a solar fuel system. Caltech and the Massachusetts Institute of Technology have a$20 million National Science Foundation (NSF) grant to improve photon capture and and catalyst efficiency, while several Energy Frontier Research Centers funded by the US DOE are focused on AP.