Tuesday, August 14, 2012: 5:10 PM
Meeting Room 11-12, Columbia Hall, Terrace level (Washington Hilton)
The use of dielectrophoresis (DEP) for the fabrication of monolayer coatings of photoreactive cyanobacteria and adhesive polymers may allow engineering of highly reactive multi-layer, multi-organism immobilized microbial photobioreactors with stable performance after drying and rehydration, optimal photoreactivity and minimal mass transfer limitations, light scattering and self-shading by precisely controlling cell packing and orientation. DEP is being used to fabricate 1-cell thick coatings of Synechococcus PCC 7002 for fundamental studies of light absorption and scattering, cell packing and reactivity after drying and rehydration. This organism can be genetically modified to produce fuel precursors from CO2 with simultaneous energy capture from sunlight and O2 production. Adhesion between cells and the substrate is engineered by priming a surface-activated polyester substrate with a layer-by-layer (l-b-l) assembled multilayer film of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonic acid) (PSS) [(PAH-PSS)3PAH] which has a positively charged polyelectrolyte outermost layer that interacts with the negative charges on the Synechococcus surface. This is the first report of the use of DEP and polyelectrolytes to fabricate adhesive monolayer coatings of photoreactive cyanobacteria. Permanent chains and monolayer coatings of Synechococcus that remain aligned after the electric field is turned off can now be fabricated on polyelectrolyte-coated flexible polyester using this approach. Future work will be to determine the microstructure and optimal cell packing of the DEP coatings, to develop sensitive methods for reactivity analysis and to adapt this DEP method for the fabrication of multi-layered coatings that will combine different types of photosynthetic organisms into highly reactive biomimetic devices.