연꽃은 흙탕물에서 자라지만 잎 표면이 매우 깨끗한데 그 원리가 바로 ‘연잎효과’(Lotus effect) 때문이다. 연잎에 떨어진 물방울은 그냥 굴러 떨어지고, 그 물방울이 굴러 떨어지는 동안 먼지도 같이 없어진다. 반면에 일반적인 물체의 표면에는 물방울이 굴러 떨어져도 먼지는 그대로 남는다.
연꽃잎의 미세한 돌기로 인해 물방울은 맺히지만 먼지가 표면에 달라붙지 못하기 때문에 물방울과 함께 제거되는 것. 과학자들은 “미세 현미경으로 연꽃잎을 관찰하면 잎의 미세한 돌기로 인해 높은 접촉 각도가 생기고 물방울이 그대로 맺히게 된다”고 설명한다.
이 연잎효과는 생체모방기술로 공학적으로 많은 아이디어를 제공한다. 이를 이용해 필름을 코팅한 유리와 거울이 있는가 하면 지난 2009년 10월 포스텍 화학공학과 용기중(42) 교수 연구팀은 연잎효과를 활용, 돌기 대신에 다양한 물질의 나노선(Nano wire)에 발수물질을 코팅해 초발수성 표면을 제작하는 기술을 개발했다.
또 지난 10일 용기중 교수 연구팀은 연잎효과에 착안힌 또 하나의 개가를 올렸다. 그건 바로 빛의 방향에 따라 반응하는 메모리 소자. 용 교수는 “나노소자와 생체모방기술을 접목해 빛의 입사각에 따라 저항변화 특성이 조절되는 소자기술을 개발했다”고 발표했다.
이처럼 생체모방기술이 항후 고령화 시대의 대안으로 활발하게 연구되고 있다. 그중 가장 관심을 끄는 분야가 바로 고분자 액츄에이더로 작동하는 인공근육과 탄소나노튜브(CNT)로 된 생체모방신경이다. 전문가들은 “고령화시대를 맞아서 신경모방기술이 인공감각기관으로 진화할 것”이라고 말한다.
나노기술(NT)과 더불어 생체모방공학은 장애인과 노인의 한계를 넘어 진짜 600만 불의 사나이의 탄생을 향해 서서히 진화하고 있는 중이다.
장애인과 노인을 위한 생체모방기술
90년대 과학계를 뜨겁게 달군 이슈 중의 하나가 나노기술(NT)이다. 그중 가장 첨단을 달라고 있는 분야 가운데 하나가 바로 생체모방기술이다. 이 기술은 거동이 불편한 장애인과 노인들을 위해 빠르게 발전하고 있다.
지난 2009년 영국에 사는 에릭 존스(Eric Jones)씨는 암투병 중 손가락의 대부분을 잃는 불행을 당했다. 그런데 절망에 빠진 그에게 한 줄기 희망의 빛이 비쳤다, 그건 바로 영국의 터치바이오닉스(Touch Bionics)사가 개발한 ‘프로디지트(ProDigits)’라는 이름의 바이오닉스 기술이었다.
그는 이 기술의 도움으로 현재 장난감 레고 블록을 집을 수 있게 됐다. 프로디지트란 불의의 사고나 당뇨병, 암 등으로 부분 또는 완전 절단된 손가락을 대체하는 기술을 말한다.
그의 인공손가락 내부에는 컴퓨터 회로기판이 들어 있다. 즉, 환자에게 남아 있는 손가락이나 손바닥으로부터 오는 근육신호를 제어하는 소형전자센서가 들어 있어서 이를 통해 로봇 손가락을 움직인다. 또 하나는 손바닥뼈를 둘러싼 근섬유에 대응하는 압력을 이용한 터치패드를 사용하는데 거의 로봇과 비슷한 수준으로 알려져 있다.
생체근육은 액틴이란 가는 섬유와 미오신이란 굵은 섬유로 이뤄진 무수한 단백질 다발로 구성되어 있고, 인체 전기신호에 따라 섬유가 교대로 미끄러져 전체 다발의 수축-이완을 반복 유도하며, 적절한 부피 변형과 힘을 만들어내는 기능을 갖고 있다.
인공근육도 생체근육과 유사한 작용을 해야 한다. 따라서 환경적인 자극요소에 의해 변형, 응력, 변형속도 등이 제어될 수 있는 특성이 요구된다. 전문가들은 “힘의 증가, 신속한 응답, 저전력 구동에너지 등의 성능을 향상시키는 것이 중요하다. 또 사람 몸의 생체적 합성 및 생체조직과의 연계성도 매우 중요한 문제점”이라고 지적한다.
그럼에도 불구하고, 기존의 인공근육은 부피가 너무 커서 노인 환자나 장애인의 활동에 상당한 제약을 가하는 것이 사실이다.
그런데 최근에 노인과 장애인들에게 희소식이 생겼다. 간단한 생체전기신호에 의해 적절하게 수축과 이완이 가능한 전기활성 고분자(EPA)의 등장으로 인공근육의 부피가 작아지고 있기 때문이다. 그 주인공이 바로 탄소나노튜브(CNT). 이 기술을 응용한 생체모방기술은 한 차원 더 높은 곳을 향하고 있다.
600만 불 사나이의 부활
우주비행사 스티브 오스틴은 훈련 도중 불의의 사고로 두 다리, 한쪽 팔 그리고 오른쪽 눈을 잃지만 6백만 불의 거금을 들여 커다란 트럭도 들어 올릴 수 있는 무쇠팔, 100m를 3.7초에 달리는 두 다리, 그리고 천리도 내다볼 수 있는 눈 등을 새로 갖는 행운의 사나이가 된다.
70년대 최고의 인기를 구가했던 미드 ‘6백만 불의 사나이’는 생체공학((Bionics)이 나오기도 전에 시대를 앞서가는 작가의 뛰어난 상상력에서 탄생했다. 따라서 어디까지나 이야기에서만 존재할 뿐이다.
하지만 21세기 들어 발전하고 있는 나노기술을 통해 과학자들은 6백만 불의 사나이를 이야기속에서 끌어내고 있다. 과연 600만불의 사나이가 탄생할 수 있을까?
천리안의 가능성은 시각생체모방기술에서 찾을 수 있다. 인간 눈의 망막에 심은 이미지 센서는 외부에서 들어온 빛을 화소단위의 전기적 신호로 바꾸어준다. 이것이 바로 CCD(Charge Coupled Device)다. CCD는 빛에 의한 전자들을 출력부까지 이동시킨 후, 전압형태의 신호로 변환시킨다.
이 신호가 광섬유를 타고, 수정체 뒤쪽으로 흘러가면 망막보철이 감응하고, 이 신호는 다시 시신경을 거쳐서 뇌에 전달되면 사물을 인지할 수 있다. 이 기술이 발전하면 미래에 천리안이 가능하지 않을까?
말보다 빨리 달리는 두 다리와 강력한 오른팔은 인간의 머리카락보다 10배나 작은 지름이지만 인공근육보다 1천배 강도가 높은 신소재 탄소나노튜브(CNT)를 이용한 생체신경기술에서 그 가능성을 찾을 수 있다.
지난해 이탈리아 트리에스테대학(University of Trieste) 연구진은 다중벽 탄소나노튜브와 척수를 연결, 나노물질과 신경 세포와의 상호작용을 관찰한 결과 뇌의 신경세포와 닮은 탄소나노튜브는 뛰어난 전기 신호 전도체이고 세포 멤브레인과 기계적으로 접합해 신경 구조와 기능적인 연결을 할 수 있음을 알아냈다.
연구진은 “이 연구결과는 신경 공학에서 나노물질의 적용을 증가시키는데 일조할 것”이라고 말했다.
올해 국내 포스텍 연구팀도 적은 전압으로 인공근육을 움직이게 할 수 있는 전기 감응성 고분자 액츄에이터를 개발했다. 이 기술은 마이크로 센서뿐 아니라 로봇과 인공 근육 등 생체 모방형 기술에 응용 가능성이 뛰어난 것으로 알려졌다.
이렇듯 빠르게 진화하는 생체모방기술의 발전은 ‘600만 불의 사나이’의 부활이 불가능한 것만은 아니란 사실을 말해준다.
사이언스타임즈
The popular dream of flying cars, however, lands us slap-dab in the middle of hoverboard country, where we're forced to contemplate the bugbear that is antigravity technology. While the ability to manipulate antigravity would transform transportation immensely, the subject is largely taboo in research circles due to numerous hoaxes and unfounded claims. This doesn't mean serious minds aren't interested. Between 1996 and 2002, NASA's Breakthrough Propulsion Physics Project explored the possibilities of antigravity.
Researchers in France did create a skateboard that can levitate a couple inches off the ground, thanks to some insanely cool superconductor technology [source: Smalley]. Sure, it can only go in a straight line and at a height of a few inches, but who cares: "Back to the Future" is nigh!
8
Underwater City
The ocean presented early humans with a vast mystery. What worlds and fabulous creatures exist in the deep? Today, our understanding has expanded, but the world's waters still offer us an abundance of mystery and awe. We dream less about mermaid cities and sunken Atlantis and instead imagine underwater metropolises and seafloor colonies.
This zeal was especially strong in the late 1950s and early 1960s, when Jacques Cousteau's Conshelf project and the United States Navy's Sealab saw the dream of undersea living realized. Both programs proved that humans can live and work for an extended time underwater. The test subjects tended underwater gardens, tackled underwater construction projects and lived the life of an aquanaut.
Half a century later, the underwater cities still aren't here. Sure, we have unrealized designs such as Giancarlo Zema's semisubmerged Trilobis 65 dwelling and the proposed underwater Dubai skyscraper Hydropolis, but very few underwater habitats. The bottom line is that while humans can live underwater, it's not an easy or cheap life. It's also not necessary.
Circumstances haven't forced humans to consider underwater living seriously, and when it comes to oceanic exploration, unmanned submersibles and automated seafloor stations offer a better value proposition. The National Science Foundation's Ocean Observatories Initiative, for example, calls for a worldwide network of automated observation stations and autonomous underwater vehicles.
7
Robot Maids
The most obvious answer to a complaint about the lack of robot maids is of course, "Hey, buddy, go buy a Roomba." Because while they don't really resemble George Jetson's robotic maid Rosie, modern bots do carry out a host of floor vacuuming, tile scrubbing and pool cleaning chores.
Of course, the vision of the computerized maid goes beyond mere automated dust busting. What we've been waiting for is a true robotic domestic servant capable of safely navigating a human living environment to carry out everything from cleaning the toilet to cooking pancakes.
But in order to actually move through our kitchens and interact with us, robots will need to be capable of social learning. A truly social bot will need to evaluate environmental stimuli with a discriminating eye. In short, a true robotic maid would need to be autonomous. Scientists from Cornell University are on the case, and are slowly creating robots that might be able anticipate human needs. They predict that in the next few years we might see a robot maid who can do some specific tasks. So far, they've already developed a "robo-maid" who can open a fridge and pour you a beer [source: Carroll]. A far greater help than, say, folding laundry.
6
Ticket to Mars
The date was July 20, 1969, the day Apollo 11 landed the first human beings on the moon. It was the farthest we had ever traveled from the Earth and the first time humans ever stood on another object in our solar system and stared back in wonder at the world they called home. From there, it only seemed natural that humans would venture to Mars as well.
As early as 1946, the aforementioned German-American rocket scientist Dr. Wernher von Braun sketched out Marsprojekt, which called for no fewer than 70 astronauts aboard a fleet of 10 Mars-bound spacecraft [source: Wade]. As ambitious as this sounds, the project marked the first technically comprehensive design for a manned expedition to the red planet. It was far from the last, however, as both the United States and the Russian space programs continued to cook up manned Mars expedition studies throughout the rest of the 20th century. The Curiosity Rover, which landed on Mars in August 2012, has done some of the legwork for future explorations by collecting scientific samples and studying the planet's environment [source: NASA].
But sending a friendly rover to Mars is a lot easier than actually conquering the technical challenges of sending astronauts there, which include shielding them from radiation exposure and overcoming the health worries that long-term exposure to microgravity in space might cause. In 2010, President Barack Obama set a goal of launching a manned mission to Mars sometime in the 2030s, long after he leaves office. We'll see if that actually ever happens [source: Matson].
5
Food in a Pill

WILL WE ONE DAY SURVIVE ON PILLS ALONE? (ISTOCK/THINKSTOCK)
Since the 1800s, futurists have been dreaming about creating miniaturized, 100-percent synthetic food from chemicals, so it could be consumed in tablet or capsule form. Some envisioned it as a way to free homemakers from the drudgery of cooking or spare animals from slaughter, while others saw it as a way to feed the planet's growing population without overtaxing farm soil or other natural resources [source: Belasco]. A 1936 Popular Science Monthly article predicted that "modern alchemists" in food laboratories eventually would create "food pills that would contain everything necessary for life -- a feat that would render man forever independent of natural resources for his nourishment, and banish fear of crop failure and famine" [source: Rosner].
It's an idea that has persisted over the years in science-fiction fantasies. The problem is that unless someone figures out a way to alter the laws of physics, getting your daily nutrition from a capsule or tablet is pretty much impossible. Think of it this way: The typical human needs to ingest about 2,000 calories each day, and a gram of fat -- the most efficient way to provide them -- contains about nine calories. Thus, to meet your daily caloric requirement, you'd have to ingest 450 or so standard-sized capsules of fat, which would weigh roughly half a pound. And you still wouldn't be getting all the other nutrients -- protein, carbohydrates, vitamins, minerals, fiber -- that you need to be healthy [source: Biba]. Besides, eating nothing but a pill for breakfast, lunch and dinner wouldn't exactly be living large. People like to eat because food tastes good. Pills generally don't.
4
Jet Packs

GRANT ENGLER CELEBRATES TYING THE KNOT AFTER THE FIRST WEDDING BY WATER-POWERED JET PACK. (© LEONARD ORTIZ/ZUMA PRESS/CORBIS)
If you've ever seen the classic James Bond flick "Thunderball," you probably remember that great action scene in which 007 makes his escape from some bad guys by slipping on a rocket-equipped backpack and blasting off into the sky [source: Parker]. Jet packs were first dreamed up by German scientists during World War II, and after the war, the Pentagon longed to develop its own version [source: Kaku].
In the 1950s, at Bell Aerosystems in New York, a visionary engineer named Wendell F. Moore created his own version of the concept, a 125-pound (57-kilogram) "rocket belt" powered by a canister of liquid nitrogen. For its part, the U.S. military eventually gave up on jet packs as a practical mode of battlefield transportation, in part because flyers could only carry enough fuel to stay aloft for less than half a minute [source: Rocketman.com].
But we are getting really close to the jet packs we were promised. New Zealand-based Martin Aircraft has approval for manned test flights of its P12 Jetpacks. And although the company has sent unmanned packs 5,000 feet (1,524 meters) in the air, these manned flights will only be 20 feet (6 meters) over land and 25 feet (7.6 meters) over water [source: Oremus]. And guess what -- the company is taking orders. Law enforcement and gover
3
The Air-conditioned Suit
The first air conditioning unit was developed by Willis Carrier in 1902, and within a couple of decades, summertime crowds were escaping the heat by flocking to movie theaters equipped with the new technology [source: Bucknell.edu]. But air conditioning had a drawback: It required people to stay indoors to stay cool. Wouldn't it be better if you could wear air conditioning on your body, so you could stroll down the street on the hottest day in July without breaking a sweat?
Futurists dreamed of just that. In 1953, for example, an Iowa newspaper columnist cheerfully predicted that in the future "Zipper suits" with built-in air conditioning units would keep the body cool in the summer and warm in the winter. Such an outfit would eliminate the need for large wardrobes. "When one traveled he would simply tuck a couple of pair of socks in the pockets of his all-weather suit, set the thermostat for 68 degrees and depart," the journalist wrote [source: Sioux Center News].
Decades later, we're getting oh-so-close to a frosty tux. First there was a Japanese company that, in the late 2000s, marketed a shirt with a small built-in fan that could be powered by plugging it into a computer's USB port [source: Chen]. After the 2011 Japanese earthquake and tsunami, when electricity restrictions were strict, Japanese manufacturers made fan-driven air-conditioned clothing using lithium ion batteries as a charge. The jackets, pants and shirts puff with air that circulates in the insulated material, and the company saw robust sales [source: Carbone].
2
Atomic Powered Homes

WE HAVEN'T QUITE FIGURED OUT HOW TO SQUEEZE NUCLEAR REACTORS INTO THE HOME YET. (ISTOCK/THINKSTOCK)
In the 1950s, when the U.S. government first approved the creation of nuclear plants for generating electricity, some Americans fantasized about a future in which small, personal nuclear reactors would be commonplace gadgets. In 1955, Robert E. Ferry, general manager of the Institute of Boiler and Radiator Manufacturers, gave a speech in which he predicted that individual homes would be heated and cooled by small reactors within three to six years.
Although that hasn't happened nearly 60 years later, there was some movement to create "mini-reactors" that might power small communities or even homes. As recently as 2008, company Hyperion Power Generation (now Gen4 Energy) was claiming that it had developed nuclear power plans "smaller than a garden shed" that could power 20,000 homes and would be on sale by 2013 [source: Vidal and Rosen]. However, 2013 hit, and still no progress on this nuclear sunset.
1
Computer Smarter Than a Human
Amid all the phantasmagoric special effects and puzzling symbolism of Stanley Kubrick's 1968 film "2001: A Space Odyssey," the one detail that sticks in everyone's memory is the HAL 9000 computer that ran most of the spaceship Discovery One's operations. Not only did HAL speak and possess a humanlike personality, but it actually was superior to humans, because it never made mistakes.
But when the year 2001 actually rolled around, what inventor and futurist Ray Kurzweil calls "strong AI" -- that is, a machine that possesses self-awareness and is equal or superior to humans in intellectual ability -- was still closer to science fiction than reality.
That's with a few caveats. In 2011, the supercomputer Watson went head-to-head with "Jeopardy!" contestants and won mightily. However, just because a computer can answer questions -- and Watson is a very sophisticated "question-answering machine" -- it doesn't necessarily mean it's smarter than a human [source: Markoff].
In a 2005 essay, Kurzweil, who estimates that a computer would need to be capable of performing 10 quadrillion calculations per second to match all the regions of the human brain, predicted that threshold would be reached by 2020 [source: Kurzweil]. (Watson uses 80 trillion operations per second, the slowpoke [source: Deedrick].)
Others, such as Microsoft co-founder Paul Allen, have expressed doubts about whether machines ever will be able to even approximate human intelligence. He noted that neuroscientists still don't really know enough about the brain yet to hope to duplicate it. "You can't create an artificial intelligence," Allen insisted in a 2012 Forbes interview, "unless you know how the real thing works."









