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?
Planetary medicine is now a growing field in which the expertise of medical professionals in directed towards issues of global health and environmental protection, particularly including climate change.1,2 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. Professor Faunce presented these first at the Nanotechnology for Sustainable Energy Conference sponsored by the European Science Foundation in July 2010 at Obergurgl, Austria and at the 15th International Congress of Photosynthesis in Beijing in August 2010.
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 well as the need to establish a comprehensive adaptation program including international support for those countries most vulnerable to its adverse effects.1 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 Copenhagen Accord also contains important undertakings concerning mitigation (including the Copenhagen Green Climate Fund) in particular establishing a mechanism to accelerate renewable energy technology development and transfer.3
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.4 These critical survival issues for the poor will be exacerbated as global population grows towards 10 billion by 2050 and energy consumption rises from 13.5 TW (2001) 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 photosystem II to oxidize water (H2O) to oxygen (O2) which is released to the atmosphere. The electrons thereby produced are captured in chemical bonds by photosystem I to reduce NADP (nicotinamide adenine dinucleotide phosphate) for storage in ATP (adenosine triphosphate) and NADPH (nature's form of hydrogen).5 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.6
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.7 Enhanced AP, if applied equitably, could assist crop production on marginal lands, reduce atmospheric CO2 levels, lower geopolitical and military tensions over fossil fuel, food and water scarcity and create hydrogen for industrial storage.8
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.9,10
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,11 mesoporous thin film dye-sensitive solar cells of semiconductor nanoparticles12 and carbon nanotubes harvesting and conducting the resultant electricity.13
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.14 Synthetic proteins (maquettes) have been created to allow testing of engineering principles for artificial photosystems and reaction centers.15
Numerous competitively funded nanotechnology-focused AP research teams already exist in many developed nations.16 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 catalyst efficiency, while several Energy Frontier Research Centers funded by the US DOE are focused on AP.
A GAP Project must overcome various organizational, financial and intellectual property challenges. The scientific challenge for the Human Genome Project HGP was perhaps more clearly defined. As with the HGP, GAP Project work is likely to be distributed across a variety of laboratories in different nations, rather than being focused in one place like the European Organization for Nuclear Research (CERN) or the international project on fusion energy (ITER).
CERN's lesson may be to have many nations funding new equipment (such as the Large Hadron Collider) open to use by independently-funded physicists from around the world. ITER highlights the benefits of signatories agreeing to share scientific data, procurements, finance, staffing. As with CERN, the Hubble Space Telescope (funded by NASA in collaboration with the European Space Agency) allows any qualified scientist to submit a research proposal, successful applicants having a year after observation before their data is released to the entire scientific community.
Industry involvement (either as suppliers of equipment or resources or customers of outputs) in a GAP project will be a major issue given the tensions between public and private rights exhibited in the final stages of the HGP. Lessons from the SEMATECH (SEmiconductor MAnufacturing TECHnology) non-profit consortium, may be that while large scale national funding and industry partners are necessary for initial momentum, global impact requires inclusion of industry from multiple nations and division into pure research and manufacturing subsidiaries.
The Center for Revolutionary Solar Photoconversion (CRSP) involves public funding from two separate sources (US DOE and NSF) with multinational corporate members (including DuPont, General Motors, Konarka, Lockheed Martin, Sharp and Toyota). Coordination with international renewable energy organizations such the International Renewable Energy Agency (IRENA) and the World Council for Renewable Energy (WCRE) and EUROSOLAR, the non-profit European Association for Renewable Energy will be important for GAP Project regulatory stability and credibility.
Potential governance models for a GAP Project could either involve gradual evolution from the status quo, or active promotion and coordination by the International Society of Photosynthesis Research (ISPR) in collaboration with leaders of the largest national AP projects. An open-access model might see funding rules requiring public good licensing, technology transfer, ethical and social implications research as well as rapid and free access to data.
A public-private partnership model might involve members' access to non-exclusive licenses over intellectual property as with CRSP. A governance structure emphasizing international law might protect photosynthesis from damage or excessive patents within the class of United Nations treaties involved with protecting the common heritage of humanity (for instance moon, outer space, deep sea bed, world natural heritage sites) with obligations to roll out AP technology equitably.
Capturing, converting and storing secure, carbon-neutral, sustainable energy from its most abundant source, the sun may be the most important scientific and technical challenge facing humanity in the 21st century. A multidisciplinary GAP Project could be a definitive exercise in planetary nanomedicine.
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- Schwartz BS, Parker C, Glass TA, Hu H: Global environmental change: what can health care providers and the environmental health community do about it now? Environ Health Perspect 114 (12), 1807-12 (2006).
- United Nations. Framework Convention on Climate Change. Draft decision -/CP.15 CONFERENCE OF THE PARTIES Fifteenth session Copenhagen, 7-18 December 2009 FCCC/CP/2009/L.7 18 December 2009
- Salamanca-Buentello F, Persad DL, Court EB, Martin DK, Daar AS et al: Nanotechnology and the Developing World. PloS Med. 2, e97 (2005).
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- Hurst JK: In pursuit of water oxidation catalysts for solar fuel oxidation. Science 328, 315-316 (2010).
- Pace R: "An Integrated Artificial Photosynthesis Model" in Collings A and Critchley C. Artificial Photosynthesis: from basic biology to industrial application. Wiley-VCH Verlag. Weinheim. 13-34 (2005).
- Nam YS, Magyar AP, Lee D, Kim JW, Yun DS, Park H, Pollom TS, Weitz DA, Belcher AM: Biologically templated photocatalytic nanostructures for sustained light-driven water oxidation. Nature nanotechnology. 5(5), 340-4 (2010).
- Nam YS, Shin T, Park H, Magyar AP, Choi K, Fantner G, Nelson KA, Belcher AM Virus-templated assembly of porphyrins into light-harvesting nanoantennae. Journal of the American Chemical Society. 132(5),1462-3 (2010)
- Engel GS, Calhoun TR, Read EL et al: Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems Nature. 446, 782-786 (2007).
- Kalyanasundaram K. & Graëtzel M: Artificial photosynthesis: biomimetic approaches to solar energy conversion and storage Curr. Op. Biotech. 21, 298-310 (2010).
- Sgobba V & Guldi DM: Carbon nanotubes-electronic/electrochemical properties and application for nanoelectronics and photonics Chem. Soc. Rev. 38, 165-184 (2009).
- Kanan MW and Nocera DG: In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and CO2. Science 321, 1072-1075 (2008).
- Koder et al: 'Design and engineering of an O2 transport protein' Nature. 458, 305-309 (2009).
- Sanderson K: The photon trap. Nature 452: 400-4002 (2008)
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