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One of the major drawbacks of solar power generation remains the high cost of raw materials needed to manufacture photovoltaic cells.
A team of researchers at the Massachusetts Institute of Technology, taking their cue from nature, have released a new study that shows that organic materials can be used to conduct electricity and emit different colors of light. The researchers took their inspiration from natural materials such as bone, which is a matrix of non-organic minerals and other substances, including living cells, and have managed to stimulate bacterial cells to produce biofilms that can incorporate nonliving materials, such as gold nanoparticles and quantum dots. These "living materials" combine the advantages of live cells, which respond to their environment, produce complex biological molecules, and span multiple length scales, with the benefits of inorganic materials, which add functions such as conducting electricity or emitting light.
MIT Assistant Professor of electrical and biological engineering Timothy Lu said that the new materials could one day be used to design more complex devices such as solar cells, self-healing materials, or diagnostic sensors. Lu remarked, "Our idea is to put the living and the nonliving worlds together to make hybrid materials that have living cells in them and are functional. It's an interesting way of thinking about materials synthesis, which is very different from what people do now, which is usually a top-down approach."
MIT researchers observed that there are many biological examples of efficient energy production. While Nature has created efficient energy generation using organic materials humanity has not yet done so, up to now using instead inorganic materials that are frequently inordinately expensive. The MIT research is accordingly seeking a way to engineer living materials so that they can be used to build more effective photovoltaic materials.
Professor Lu is the senior author, along with Allen Y. Chen, Zhengtao Deng, Amanda N. Billings, Urartu O. S. Seker, Michelle Y. Lu, Robert J. Citorik and Bijan Zakeri of a paper, "Synthesis and patterning of tunable multiscale materials with engineered cells," describing the living functional materials in the March 23 issue of "Nature Materials."
The paper's abstract notes, "Many natural biological systems—such as biofilms, shells and skeletal tissues—are able to assemble multifunctional and environmentally responsive multiscale assemblies of living and non-living components. Here, by using inducible genetic circuits and cellular communication circuits to regulate Escherichia coli curli amyloid production, we show that E. coli cells can organize self-assembling amyloid fibrils across multiple length scales, producing amyloid-based materials that are either externally controllable or undergo autonomous patterning. We also interfaced curli fibrils with inorganic materials, such as gold nanoparticles (AuNPs) and quantum dots (QDs), and used these capabilities to create an environmentally responsive biofilm-based electrical switch, produce gold nanowires and nanorods, co-localize AuNPs with CdTe/CdS QDs to modulate QD fluorescence lifetimes, and nucleate the formation of fluorescent ZnS QDs. This work lays a foundation for synthesizing, patterning, and controlling functional composite materials with engineered cells."
The MIT team's research has enormous potential for the energy field. Lu says that the hybrid materials could be worth exploring for use in energy applications such as batteries and solar cells. The researchers are also interested in coating the biofilms with enzymes that catalyze the breakdown of cellulose, which could be useful for converting agricultural waste to biofuels. The study proves the theoretical concept, with researchers highlighting such uses as the possibility of growing photovoltaic modules rather than having to manufacture these modules, suggesting that a new era of highlight efficient solar panels may soon be dawning.
Duke University associate professor of biomedical engineering Lingchong You, who was not part of the research team observed, "I think this is really fantastic work that represents a great integration of synthetic biology and materials engineering."
Written by John Daly at Oilprice.com.