WORLD

CHANGING

IDEAS

10 innovations that are enough to alter our Illustrations by The Heads of State

34 Scientifi c American, December 2012

sad1212WCI4p.indd 34 10/17/12 4:39 PM Scientists and engineers dream about big advances that could change the world, and then they try to create them. On the following pages, Scienti c American reveals 10 innovations that could be game changers: an arti cial alternative to DNA, oil that cleans , pacemakers powered by our , and more. These are not pie-in-the-sky notions but practical breakthroughs that have been proved or prototyped and are poised to scale up greatly. Each has the potential to make what may now seem impossible possible. —The Editors

sad1212WCI3p.indd 35 10/16/12 7:28 PM New -Forms, No DNA Required Artificial based on -made could thrive and evolve

DNA is passé. Synthetic biologists have invented an array of new molecules called ed truly synthetic life—life that does not XNAs that boast all the talents of deoxyribonucleic (DNA) and ribonucleic acid depend on what has already (RNA), as well as some special powers. XNAs could allow scientists to safely create provided but on humankind’s inventions. Holliger emphasizes that XNA-based life-forms in the laboratory that do not depend on DNA to survive and evolve. life-forms are a long way off, but he al- “Life is inconceivable without a system thing no other artificial nucleic can ready recognizes a distinct advantage. If for genetic storage and repli- do: they evolve. Inside living cells, en- such a creature escaped into the wild, it cation, but DNA and RNA are not unique,” zymes called cut, paste and would die without a steady supply of XNA- explains Philipp Holliger of the Medical splice DNA to access the genetic informa- specific . And XNA could not Research Council’s Laboratory of Molecu- tion. Without that interaction, DNA would weave itself into the of natural lar in Cambridge, England. “Relat- remain as inert as dusty encyclopedias on organisms, because their native enzymes ed —at least six more—can do the a shelf. Holliger reprogrammed natural would not recognize it. XNA-based bacte- same function.” That the earth’s flora and enzymes to translate DNA ria designed to devour oil spills or turn fauna rely only on DNA and RNA, he says, into XNA and back again, establishing a wastewater into electricity, for example, is an “accident from the origin of life.” novel system for storing and transmitting could not interfere with native organisms. XNA stands for xeno (xeno genetic information, which is the founda- The fact that XNA is complementary to meaning “foreign”). Like DNA, XNA has a tion of evolution. One of the XNAs, HNA DNA, yet structurally unique, makes it im- that resembles a twisted ladder. (anhydrohexitol nucleic acid), reliably pre- mediately useful for medicine, biotechnol- In DNA, four different , repre- served changes to its genetic and ogy and biology research. Holliger imag- sented by the letters A, C, G and T, form evolved to attach to a with increas- ines XNAs that could be injected into the the steps. groups and ing precision. body to detect early, subtle signs of form the ladders’ sides, also known as the Once Holliger improves the function- disease that current technologies miss. backbone. For 30 years scientists have ality of XNA and its enzymes, the set of Steven Benner, a fellow at the Founda- been tweaking the sugars to create artifi- molecules could replace DNA and RNA in tion for Applied in cial nucleic acids, which serve as research a living . Researchers might take a Gainesville, Fla., has also advanced the ef- tools in medicine that can bind to DNA. simple bacterium, for instance, suck out fort by expanding the genetic alphabet To make XNAs, Holliger and his col- its DNA and replace it with XNA. with two new nucleobases, Z and P. A larg- leagues did not simply alter the sugars in Alternatively, scientists could enclose er alphabet could form a wider array of DNA’s backbone—they substituted entire- XNA within —the origin of a and, eventually, . “The goal ly different molecules, such as cyclohex- new life-form that could evolve in ways no is to create chemically controlled systems ane and threose. Just as important, they one can predict. Whereas other synthetic that behave like biological systems, with- created enzymes that work with the XNAs biologists such as J. have out being biological systems,” Benner says. to form a complete genetic system. made remarkable advances in rewriting “We believe whatever you can draw on a The enzymes enable XNAs to do some- the existing , no one has creat- page, you can make.” —Ferris Jabr

Only a few minutes after someone stops breathing— oxygen microbubbles, which the blood can absorb whether it is from a piece of meat stuck in the throat, within seconds. The bubbles are too small to cause Foam That a severe asthma attack or a lung injury—the an air embolism—a gas pocket that stops blood flow, starts to shut down. Cardiac arrest and death are thus causing a stroke or heart attack. Restores imminent. Emergency responders and hospital work- To create this lifesaving foam, John Kheir, a cardi- ers have one primary recourse: insert a breathing ologist at Boston Children’s Hospital, and his col- tube through a patient’s mouth. That procedure can leagues adapted existing medical . Breathing be risky and time-consuming. Microparticles with membranes already deliver A new injectable solution could keep such people drugs, as well as dyes for ultrasound imaging. Kheir’s Injectable oxygen microbubbles alive for 15 minutes or more, buying crucial time to team propelled phospholipids through an oxygenated could give asthma and choking get victims to a hospital or to do some surgical gym- chamber and used sound waves to spur the ingredi- victims precious minutes nastics in an operating room. The solution contains ents to self-assemble into microparticles. The

36 , December 2012

sad1212WCI4p.indd 36 10/17/12 4:59 PM researchers then used a to superconcentrate have other organ damage than those who got saline overload that can cause heart failure. Kheir’s team is trying them into solution. Each four-micron-wide microbubble solution—despite not taking a single breath. to improve the formulation so that it requires less saline. contains pure oxygen, surrounded by a lipid film that is The approach is “a fairly innovative idea compared to Another concern is that without normal respiration, just a few nanometers thick. what we have now,” says Raymond Koehler of Johns dioxide builds up in the body, which can be toxic. Because the bubbles contain oxygen at a pressure Hopkins University, who is not involved in the work, As Koehler notes, however, the body can handle a little that is higher than in the bloodstream, the gas diffuses because most emergency oxygen procedures require the excess carbon dioxide better than it can handle a total lack into red blood cells on contact. Once a bubble is deplet- pulmonary system to function at least at a minimal level. of oxygen. If the microbubbles prove successful in further ed, the shell collapses to a disk that is less than a micron One drawback is that because the blood absorbs the (and subsequent human) trials, the solution could wide, easily passing through the circulatory system. oxygen so quickly, a constant infusion is necessary, which help emergency crews or operating room technicians buy In a test, researchers blocked the airways of anesthe- involves a lot of saline to help the foam move smoothly into crucial minutes before they can implement other lifesav- tized rabbits for 15 minutes. Those injected with the solu- the bloodstream. The amount of solution that a patient ing treatments. In those situations, Koehler says, “you tion were much less likely to go into cardiac arrest or would receive after 15 minutes could to edema, a fluid want to have a backup plan.” —Katherine Harmon

December 2012, ScientificAmerican.com 37

sad1212WCI3p.indd 37 10/16/12 7:28 PM Alzheimer’s disease remains virtually untreatable. tomography scans of living people’s , a recent More than 100 experimental drugs have failed to halt innovation, show that by the time symptoms appear, Early the condition that robs people of their memories, their amyloid has been silently accumulating for up to 20 relationships and, ultimately, their identity. Now scien- years. Perhaps by then the brain is irreversibly dam- Treatment for tists will be testing a new strategy for preventing this aged, making any drug useless. No one knows for sure, horrific condition from starting in the first place. Just as however, whether amyloid causes Alzheimer’s or is healthy people take statins to lower their cholesterol merely a by-product of the disease. The new study Alzheimer’s and avoid heart disease, people at risk for Alzheimer’s may provide an answer to this mystery. could conceivably pop pills to keep the disease at bay. Set to start early in 2013 if all approvals are grant- A drug trial of 300 Colombians Researchers will be investigating a drug that flush- ed, the investigation will involve 300 members of dis- could reveal a way to es away an intrusive protein called amyloid, suspected tantly related families in Colombia whose rare and par- as a primary contributor to Alzheimer’s. Until recently, ticularly devastating form of Alzheimer’s strikes in the prevent the disease amyloid clumps could only be seen by dissecting the of life. By their 50s and 60s, many are as helpless from ever starting brain after death. Yet advanced positron-emission as infants. Normally it is impossible to predict who will

Water Purified with Oil A simple chemical trick could clean wastewater much less expensively

Anurag Bajpayee started out looking for a better way to preserve human cells flows back up oil and gas wells, including in deep freeze. Such cryopreservation must carefully avoid frostbite—the formation fracking wells. “If you thought that sea- of ice crystals that rupture and kill cells. In 2008, while conducting experiments at water was salty, this is eight times salti- er,” Baj­payee notes of the more than nine Massachusetts General Hospital, Bajpayee inserted the antifreeze glycerol into the billion liters of contaminated water pro- cells, along with soybean oil, which helped to concentrate the glycerol. During his duced by the nation’s oil and gas wells Ph.D. qualifying exam the next year, at the Massachusetts Institute of Technology— every day. typically a tense affair—a curious conversation broke out with his interviewers when Encouraged, Bajpayee is already test- he described the soybean oil’s effect. Why not use the soybean oil, they proposed, to ing decanoic acid against six different oil remove impurities from water? “I think it’s one of the very few qualifying exams that and gas brines that were taken from dif- resulted in a patent application,” Bajpayee says. ferent parts of the U.S. Conventional technologies for treating such wastewa- Bajpayee soon created a simple pro- oil, a fatty acid. Most of it repels water, ter include reverse osmosis, which re- cess that uses an unusual class of oils to but at one end is a , known as a quires special membranes that can clog take contaminants out of water. The pro- carboxylic acid group, that readily forms and foul easily; distillation, which con- cess could be a boon to cities, industries a with water. sumes copious amounts of energy; and, and agricultural operations—all of which “It surprised me that it would actual- most commonly, dumping the water create vast amounts of dirty water—by ly work,” says organic chemist Jean- back down a disposal well. Bajpayee will providing ways to clean that water that Claude Bradley of Drexel University, who also need to figure out a way to speedily could be much less energy-intensive or also noted that the phenomenon could process wastewater continuously rather expensive, or both. have been discovered a century ago. “It’s than treating batches of it in beakers and Soybean oil is among a small number the coolest thing I’ve seen in test tubes. of oils that seem to serve as so-called di- for a long time.” To make a real impact in oil and gas rectional solvents. That is, they dissolve Bajpayee’s experiments showed, how- drilling, “we’ll have to beat the cost of the water without dissolving other mole- ever, that purifying a single cup of water cheapest alternative, which right now is cules that are in the water, such as salts. would require enough soybean oil to fill dumping,” Bajpayee admits, although Soybean oil can absorb water when heat- a swimming pool. So he looked for an- more and more communities do not want ed to as little as 40 degrees Celsius, leav- other directional solvent that would be wastewater sent underground and lost ing behind contaminant molecules, which more efficient and settled on decanoic that way. In the meantime, more research are then skimmed away. Simply cooling acid, which occurs naturally in milk and will tell if decanoic oil or some other di- the mixture allows the cleansed water to which bonds even more readily to water. rectional solvent could cleanse dirty flow back out to be captured. The solvent This fatty acid could turn into wastewater or desalinate seawater more thus remains undisturbed, ready to clean fresh, but it appears to work best for inexpensively than current processes— more water. even saltier brines, such as the residue of giving water treatment a new direction. The key is the carbon backbone of the mining or the chemical-laden water that —David Biello

38 Scientific American, December 2012

sad1212WCI4p.indd 38 10/17/12 5:00 PM develop Alzheimer’s, but in this extended family, a single age; spinal taps to measure tau protein, which is associat­ Institutes of Health. Even if the drug succeeds, there is no genetic , detectable by a blood test, spells doom. ed with brain ; and memory and thinking tests guarantee that the results will translate to the much more Eric Reiman, executive director of the Banner Alzhei­ designed to pick up subtle cognitive lapses, such as forget­ common form of Alzheimer’s that afflicts the elderly. Yet mer’s Institute in Phoenix, his colleague Pierre Tariot and ting a list of words that were memorized only minutes or the researchers hope this trial will establish for Alzhei­ their Colombian collaborator Francisco Lopera realized hours earlier, a marker of emerging Alzheimer’s. mer’s what cholesterol and high blood pressure are for that the family provided a unique opportunity to test the The study will also enlist up to three dozen patients in cardiovascular disease—intermediate signposts that aid benefits of early intervention. They plan to give an experi­ the U.S. The Americans, who will receive the same treat­ research, diagnosis and treatment. mental drug, crenezumab, to 100 family members who are ment, will be a less homogeneous bunch, possessing vari­ The data they collect could mean that instead of having on the cusp of developing Alzheimer’s symptoms and a ous in any of three genes linked to early-onset to wait years to see whether an experimental drug helps placebo to 100 others. A third group not destined to get the Alzheimer’s. Investigators hope to learn whether it is pos­ patients, researchers could quickly gauge results from subtle disease will also receive the placebo. sible to extrapolate from the Colombian family to others biological shifts such as smaller brain size or changes in tau Participants will receive biweekly injections for at least who are destined to develop dementia in middle age. or amyloid deposits. “We need to develop faster ways to test five years. Every few months they will undergo extensive The $100-million study is funded by the drug’s maker, the range of promising therapies and find ones that work testing: magnetic resonance imaging to track brain shrink­ , as well as by philanthropists and the National as soon as possible,” Reiman says. —Emily Laber-Warren

December 2012, ScientificAmerican.com 39

sad1212WCI3p.indd 39 10/16/12 7:28 PM How “sustainable” is a can of soda or a bottle of social costs. That is the idea behind the Sustainability shampoo? An increasing number of consumers want Consortium, a collection of 10 leading universities, The Ultimate to base their buying decisions on the answer, but large nonprofit organizations and 80 international finding a comprehensive measure for the negative companies—including Walmart, Coca-Cola and Dis- Sustainability impact that the making of a product might have on ney—that have agreed to devise a standard index cov- the planet is difficult. Scores of “sustainability indexes” ering the entire supply chain. The group recently scrutinize discrete stages of the supply chain or differ- unveiled the measures its members will use to evalu- Index ent effects—such as landfill waste generated or car- ate a first set of 100 products, ranging from breakfast A new rating system bon dioxide emitted—and use different metrics sup- cereals to laundry detergents to televisions. exploits corporate pressure ported by different groups. The problem is not a lack Advocates such as Jeff Rice, Walmart’s director of of information; it is too much of it. sustainability, argue that sustainable practices across to clean up all stages Judging products would be much easier if there the supply chain not only can clean up the environment of the supply chain were one set of metrics to evaluate environmental and but also can cut costs by, for instance, reducing the

40 Scientific American, December 2012

sad1212WCI4p.indd 40 10/17/12 5:01 PM for Fetuses A noninvasive procedure could reveal thousands of disorders not discernible now

Researchers have recently shown that they can construct a complete genetic Scientists led by picture of a fetus—the full genome—simply by taking a blood sample from the bioengineer Stephen Quake have recon- mother. The procedure could revolutionize genetic screening by revealing single- structed the fetal genome using only a ma- ternal blood sample. They first seek haplo- disorders such as cystic fibrosis, Tay-Sachs disease or fragile X syndrome long types that the fetus inherits from the before a fetus is born—giving doctors time to begin possible prenatal therapies and mother, which will likely be the most com- giving families time to prepare for their child’s needs. mon in the plasma because mother and child share them. Quake then uses genetic One percent of the population lives ence of fetal DNA in a pregnant woman’s markers from the mother to identify the with a single-gene disorder. Since 2011 blood plasma. That meant it was possible rest of her genome. that do doctors have been able to determine from to separate the two DNA types and use the not appear in the mother’s genome are a mother’s blood sample if her fetus has an fetal portion to construct a full genome. unique to the fetus and may have come abnormal , which could indi- Researchers started looking for haplo- from the father or a mutation. cate conditions such as Down syndrome. types—clusters of adjacent gene sequenc- Despite progress, challenges remain— That level of information cannot reveal es. Different search methods could distin- notably, lowering the cost and raising the most of the roughly 3,500 single-gene dis- guish the variety of haplotypes in a plasma accuracy of sequencing. The larger chal- orders, however. Physicians can withdraw sample and indicate which came from the lenge is how to interpret the genome. “Our a placental tissue or an amniotic fluid mother or fetus. The haplotypes could ability to detect genomic changes has out- sample to check for those conditions, but then be reassembled into a full genome. paced our ability to correlate many of these invasive tests carry a risk of miscar- The approach was easier said than those changes with human diseases and riage women may not be willing to take. done; it would require sophisticated tech- characteristics,” says Brenda Finucane, The new noninvasive approach would nology that has only recently become prac- president­ of the National Society of Genet- give mothers unprecedented detail about tical. In the past year Jay Shen- ic Counselors. Many doctors believe it is their child without endangering their dure of the University of Washington de- premature to embrace screening before pregnancy. It could also reach more wom- ­veloped a technique that entailed sequenc- clear guidelines are set for its use. en worldwide because the procedure does ing a full paternal and maternal genome Critics also fear that the procedure not require a trained obstetrician. Some from a father’s and a mother’s blood, could lead to abortions, as parents discov- researchers envision do-it-yourself kits then using those data to distinguish be- er that their fetus has an incurable condi- that mothers would send to a lab. tween maternal and fetal haplotypes in tion. Yet doctors such as Diana Bianchi of The procedure stems from a discovery the mother’s plasma. In the process, Shen- Tufts University believe the benefits could made in 1997, when chemical pathologist dure can discern mutations that arise outweigh fears—particularly if screening Dennis Lo, then at the University of Ox- spontaneously in the fetus, which could enables prenatal­ treatments that can alter ford, and his colleagues detected the pres- help in spotting rare conditions. debilitating diseases. —Daisy Yuhas

amount of waste that needs to be hauled away. Walmart is The consortium believes its index will ultimately super- “That in and of itself is going to make sustainability more building the metrics into “scorecards” that it has begun dis- sede other ratings schemes. Consumers can already walk mainstream than anything else ever has,” Rice says. tributing to the roughly 400 buyers who procure the retail- into a grocery store, whip out their mobile phones, scan a It will be several years before consumers can access er’s products. Buyers will develop plans with suppliers to bar code on a bottle of shampoo and pull up a sustainabili- the index’s data. Consortium leaders expect to make it reduce environmental impacts, and whether suppliers act ty ranking compiled by GoodGuide. But the guide is built available but have not yet determined how consumers will be discussed in the buyers’ performance reviews. only on publicly available information. The consortium’s would be able to access it. In the meantime, the index Consortium member Dell is already asking contrac- ratings will factor in closely held data on emissions, waste, could spur innovation. Researchers at the University of tors that produce its LCD screens to figure out how to labor practices, water usage and other sensitive factors that California, Berkeley, for one, produced a white paper for reduce the emission of perfluorocarbons (powerful green- will become available only as large corporate players exert the consortium reviewing the advantages of using bio- house gases) created when the screens are manufactured. pressure on suppliers to disclose them. The data should based materials in laptops instead of plastics. And scien- The consortium’s data “gave us a guide of where to target make the index more comprehensive than others. Compa- tists at the University of Arkansas are studying the best our efforts,” says Scott O’Connell, director of environmen- nies the size of Walmart, Best Buy and Dell control hun- ways to evaluate impacts of various crop practices on tal affairs at Dell. dreds of billions of dollars in annual spending by suppliers. water scarcity. —Adam Piore

December 2012, ScientificAmerican.com 41

sad1212WCI3p.indd 41 10/16/12 7:28 PM be at any point during the day. They can also figure out This reality mining, a classic “big data” challenge, is from phone records who our friends, family and co- in its infancy. Companies are just beginning to sell the Mining the workers are, when we are likely to get the flu, and what data to marketers, and cell phone carriers are releasing the demographics of any major metropolitan street to researchers only limited data sets that are “anony- Mobile Life corner will be at any moment. mized” to preserve the privacy of individuals. The three The key to this explosion of data is smartphone biggest players—Google, Apple and Skyhook in Boston, A wealth of data from smartphones penetration, which surpassed 50 percent in the U.S. one of the original location service providers—are all is waiting to change our lives, this year. Nearly every one of those devices, by default, treading lightly in handling this information, for fear if only we let it sends a steady stream of location data back to central- that intrusive uses might provoke a consumer backlash. ized servers because few users bother to opt out of The technology could provide widespread benefits The dream—or nightmare—of near-flawless surveillance is on such data collection or are even aware that they can. such as fewer annoying ads and the containment of us, and it is starting to change our lives in ways few of us could Scientists and commercial researchers are figuring disease outbreaks. Yet to the few consumers who are have imagined. Companies that parse location data emitted by out how to plow through the billions of coordinates, aware of it, “this is very scary stuff—it’s Promethean our cell phones can now accurately predict where each of us will enough to chart the movements of millions of people. fire,” says Alex “Sandy” Pentland, who coined the term

sad1212WCI4p.indd 42 10/17/12 5:02 PM “reality mining” when he and his students pioneered the example, work in Haiti allowed relief agencies to send texts Insights into consumer behavior could expand as analysis of smartphone location data in the mid-2000s. to cell phone users whose location histories indicated that a result. Researchers have already found that the people Currently firms such as Skyhook and PlaceIQ in New they might have been exposed to cholera. most likely to click on a smartphone ad—and therefore York City that repackage data for marketers are careful to For reality mining to really take off, consumers would who offer the highest payoff to advertisers—are those who make location traces on individual devices unavailable. have to authorize use of even more of their data. That is are sitting in a movie theater before a film has begun, any- Google says that it deletes almost all location data after one reason why Pentland pushed discussions that led to one at home on a Sunday morning and fishers waiting for a about a week. Apple made the mistake of storing such data the proposal of the Consumer Privacy Bill of Rights in the bite. (PlaceIQ can guess that individuals are fishing because on the iPhone itself; the company has since rectified this faux U.S. and an update to the European Union’s Data Protec- their coordinates put them in the middle of a lake and they pas, but it is still less than forthcoming about how it stores tion Directive. If users feel like they control their data, they happen to match a particular demographic profile.) such information centrally and what it plans to do with it. are more likely to let companies, governments and individ- Pentland believes that once enough data are available, If the privacy concerns holding back greater use of the uals selectively access the information to provide services. reality mining will enhance public health, transportation data can be addressed, reality mining could become essen- “There’s no part of society that’s not going to use these and the electric grid, just for starters. “I like this notion of tial to how we navigate our everyday lives, not to mention data,” says Ted Morgan, CEO of Skyhook. “It fundamentally society’s nervous system,” Pentland says. “Finally, humanity enormously useful for corporations and governments. For changes how you view human behavior.” can sense what humanity is doing.” —Christopher Mims

Sugar-Powered Pacemakers The glucose in our blood could drive medical implants

Pacemakers, insulin pumps and other medical devices of the future may run with- Sarpeshkar has crafted elec- out batteries, powered instead by the same energy that fuels the body: . trodes, which do not irritate tissue or cor- rode, notes Sven Kerzenmacher, a chemi- Researchers first dreamed of glucose-powered implants in the 1960s, but the advent of cal engineer at the University of Freiburg lithium- batteries in the late 1970s provided a simpler, more powerful fix. Batteries in Germany, who is also using the material have always had a major drawback, however: they must be surgically replaced—every in his designs. Still, the body can mount five to 15 years for pacemakers. Rechargeables connect to electronics outside the body opposition to such an incursion; Kerzen- with wires that pierce the and leave a person open to infection. macher says biocompatibility is the biggest hurdle. His prototype fuel cell works well Several advances have prompted re- but researchers at Joseph Fourier Univer- in buffer solutions in the lab, he says, but in searchers to look again at glucose, which is sity in Grenoble, , packed biocom- body-fluid tests, amino acids in blood or se- plentiful in blood and the interstitial fluid patible enzymes on a graphite base, which rum caused the device to lose power. that bathes our cells. More efficient cir- produced a milder chemistry. Their disk- While a Clarkson University group has cuitry in implants, for example, has re- shaped cell is half the diameter of a dime implanted a biofuel cell in a snail, the duced power requirements. And glucose and slightly thinner. It is wrapped in mate- Grenoble group is still the only one to suc- biofuel cells are becoming much more effi- rial used for dialysis bags, which allows cessfully operate a glucose fuel cell inside a cient and body-friendly. small molecules of glucose in but keeps en- . The M.I.T. design has not been In most biofuel cells, enzymes at the zymes from getting out. In a 2010 lab rat tested in cerebrospinal fluid but in a buffer anode strip from glucose mole- experiment, the device drew glucose from that approximates body-fluid chemistry. cules. The electrons provide current as interstitial fluid and produced a stable Yet Sarpeshkar is optimistic that biofuel they flow to the cathode, where they react power output of 1.8 microwatts for 11 days. cells could enter the market in 10 years. with oxygen, forming only small amounts This year researchers at the Massachu- His silicon device produces a reliable pow- of water. Unlike batteries, however, fuel setts Institute of Technology took another er output of 3.4 microwatts per square cen- cells need to be immersed in a constant step toward commercialization. Engineer timeter. Current pacemakers need eight to supply of fuel—which blood or interstitial Rahul Sarpeshkar built a fuel cell as an in- 10 microwatts, a feasible goal. Cochlear im- fluid can readily provide. tegrated circuit on a silicon chip, using require a few milliwatts, and artifi- Excitement started to build in 2003, “the same easy-to-manufacture process as cial organs would require even more. when researchers at the University of Tex- semiconductors,” he says. His team wants As sugar-powered implants advance, as at Austin built a tiny biofuel cell that to use cerebrospinal fluid to power brain- they are opening up the possibility of tiny generated power from a grape. Since then, machine interfaces. The fluid, which cush- medical devices. Perhaps nanoscale robots a handful of groups have demonstrated the brain and spinal cord, contains that run on glucose and dispense targeted practical devices. Past models demanded plenty of glucose yet few immune system drugs will one day swim from fic- acidic conditions not found in the body, cells that could work to reject the implant. tion to reality. —Marissa Fessenden

December 2012, ScientificAmerican.com 43

sad1212WCI3p.indd 43 10/16/12 7:29 PM Scientists such as Lian Pin Koh of the Swiss Feder- deforestation. “We’re still surprised how easy it was to al Institute of Technology and Serge Wich of Liverpool assemble from off-the-shelf components,” Koh says. Drones John Moores University in England are helping to cre- The first tests in early 2012 were so successful that ate that intriguing and possibly unnerving future. After other conservationists have been clamoring for their at Home spending two and a half years and $250,000 tracking own planes. Working with a Swiss startup company, orangutans in Sumatra on foot, Koh and Wich devised Koh and Wich have now built more than 20 drones. Tiny, unmanned aircraft are ready a quicker, cheaper method. They bought a battery- The military already depends on big drones such to warn you about traffic or powered model airplane and added an inexpensive as the Predator to fight enemies and on small autono- spy on you in your backyard open-source autopilot and high-resolution camera. mous planes and helicopters to scout paths for con- For less than $2,000, they created a Conservation voys or ferret out ambushes. Officers use them to find Airborne eyes that peer down from the sky are already Drone—an autonomous plane with a 4.5-foot wing- illegal activity along the U.S.-Mexico border. But civil- changing how science gets done and how wars are fought, span that uses GPS signals to preprogrammed ian enthusiasts are getting into the act, too; they have and a commercial fleet of them is destined to radically routes and bring back remarkably detailed pictures customized drones to nab polluters, inspect drilling change how we live our lives. and data about orangutan nests and new areas of rigs, and take stunning pictures for movies and real

Electronic Tattoos Ultrathin, flexible sensors could adorn packaging, accessories, even our bodies

Engineers have built circuitry on flexible plastics, but electronics may soon reach a could be sheathed in an artificial sac that far more pliable realm: circuits that we can wear on our bodies, like tattoos, to mon- would electronically sense and correct itor our vital signs. The circuits could also be woven into clothing to power our the organ’s flawed rhythm. Such a sheath could deliver variable electrical stimula- smartphones and into food packaging to alert us about . tion to any location on the heart, thereby Rather than looking for flexible sub- five to 10 years stretchable electronics creating a much more nuanced shaping stances that can conduct electricity, John will show up in forms no thicker than a of the heart’s beating than a pacemaker. Rogers, a materials scientist at the Uni- Band-Aid. These sensors could monitor a Rogers also envisions “artificial skin over versity of Illinois at Urbana-Champaign, person’s body and transmit the results a burn site to provide artificial vascula- got the idea to take common silicon cir- wirelessly. Already mc10 has a contract ture and, at the same time, drug delivery cuitry and make it bendable. He and engi- with Reebok for an apparel-based health and stimulation to accelerate healing of neers at mc10, a firm in Cambridge, Mass., monitor. The company also has a contract that wound.” sanded silicon microchips, usually milli- with the U.S. Army to determine whether If mc10’s technology scales up, one meters thick, down to 10 or 20 microns it can produce flexible solar cells that can product could be a roll of stickers, each using well-established manufacturing pro­ be integrated into soldiers’ clothing and one a sensor. A person could bug a room cesses. They also devised ultrathin wires backpacks. In April, NASCAR driver Pau- with tiny stickers designed to pick up to connect those chips to one another and lie Harraka tested a transparent skin sound. Anything that a silicon chip can to traditional input-output ports—wires patch during a race. The patch measured sense—strain, vibration, electric fields— that can bend, fold and stretch up to twice Harraka’s level of hydration, an important could be measured by little paper-thin their original dimension. consideration in a cockpit that can roast sensors. Worn on the body or in clothing, Kevin Dowling, vice president of re- drivers for hours. Other engineers are also such devices could be powered by weak search and development at mc10, likens pursuing flexible biomedical tattoos, in- electromagnetic­ fields and could then use this configuration to “islands [the chips] cluding Nanshu Lu of the University of those same fields to report back via peo- that are anchored and oceans of intercon- Texas at Austin and a team at Korea Uni- ple’s smartphones. nects” between them that can stretch or versity in Seoul. Wide application will depend on man- bend. “If you take a Slinky made of spring Band-Aid-like sensors could stay on ufacturing innovations from electronics steel, that steel itself doesn’t stretch very the body for up to a week, acting as “bio- makers that license mc10’s technology. As much,” Dowling explains. “But a Slinky stamps” or medical tattoos that could with other transformative electronics in- can stretch 40 to 50 times its original measure heart rate and perspiration. The novations—think of the LEDs that now length without exceeding the plastic lim- circuitry is so thin and transparent that light up everything from household bulbs its of the steel. In the same way, we can it looks like a small, see-through film on to grocery stores—it is ultimately up to create metal or silicon interconnects.” the skin. the thousands of consumer device mak- Rogers, who co-founded mc10 and The circuitry could one day be embed- ers to figure out how best to apply this whose laboratory is the company’s de fac- ded inside the heart or the brain. Rogers foundational technology. to R&D operation, says that in the next imagines that hearts with arrhythmias —Christopher Mims

44 Scientific American, December 2012

sad1212WCI4p.indd 44 10/17/12 5:03 PM estate listings. “Drones are going to change the world in pioneer AeroVironment, to observe roosting sandhill cranes and researchers and usually limits the altitude to a few profound ways,” says Matthew Waite, a journalist-turned- and measure stream and sediment flows, hundred feet. But the FAA Modernization and Reform Act professor at the University of Nebraska–Lincoln who is among other tasks. Future possibilities seem endless: with of 2012, signed by President Barack Obama in February, exploring the use of drones for journalism. sophisticated cameras and sensors, small drones could tell requires the agency to develop rules permitting more civil- This revolution is being propelled by rapid advances in when crops need water, chart oil spills and report on traffic ian uses. The FAA is working with companies on the key technology. With powerful smartphone chips and open- jams. “We’re just at the tip of the iceberg of what’s possible,” technology: systems that allow drones to sense and avoid source hardware platforms such as Arduino, do-it-yourself- says Mike Hutt, manager of the U.S. Geological Survey’s other flying objects. Final rules are expected by 2015, open- ers and communities such as DIY Drones have begun to National Unmanned Aircraft Systems Project Office. ing the door to an explosion of commercial applications. build inexpensive but sophisticated autopilots that trans- The full iceberg will not come into view for several The current pause before that explosion is a boon, form radio-controlled aircraft into autonomous ones. Com- years, however, because the Federal Aviation Administra- Waite suggests. “Drones raise humongous questions panies that build drones for the military are pitching their tion has banned commercial uses of drones, fearing the about safety and ethics and law and privacy,” he says. “But wares to police departments and government agencies. confusion and accidents that could occur if thousands of now we have a rare opportunity to think about how we The U.S. Department of the Interior has already obtained unmanned craft take to already crowded skies. The FAA are going to use a technology before we actually use it.” 60 Raven planes, weighing 4.8 pounds apiece, from aviation basically allows flying by hobbyists, government agencies —John Carey

For more World Changing Ideas, including robot lifeguards, see ScientificAmerican.com/dec2012/world-changing-ideas

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