Think small. Very small. So small that a pair of tongs is dwarfed by a snowflake, so small that motors and gears can hide beneath a fleck of dandruff, so small that levers and springs are tinier than a grain of sand. And then think big. The revolution in microdevices represented by these tiny tools promises to do for machines what the incredible shrinking chip has done for electronics. Micromachines could include such wonders as gnat-size robots that pick out toxic chemicals from backyard wells. Medical researchers dream of pumps no bigger than the period at the end of this sentence that would float through the bloodstream straining out HIV-infected cells. “The greatest scientific frontier in this century is the microworld,” declares engineer Yotaro Hatamura of Tokyo University.
Calling the breakthroughs an advance in miniaturization is like dismissing the laser as a brighter light bulb. Microdevices promise a quantum leap beyond the abilities of normal machines because, starting with the first micros fashioned at Bell Labs in 1987, they are made of the same polysilicon and by the same techniques as computer chips. Thus a single chip can hold not merely a small machine, but a smart one, able to process information like any computer chip. And thousands can be made at once, dirt cheap. Colored specks on walls could be instructed to or flip over to reveal a new hue when a homeowner wants to redecorate. Mini-robots could pick out specks of gold from ore now too low-grade to bother with. “In 30 years,” says George Hazelrigg of the National Science Foundation, “this technology is going to be everywhere.”
The greatest advances may come in medicine, where micromachines could embark on a real-life fantastic voyage through the bloodstream. Polla’s device could continuously monitor levels of glucose and deliver insulin to a diabetic. At Pittsburgh’s Carnegie Mellon University, a rotor with blades no wider than three human hairs spins as blood flows through it; someday it may allow scientists to determine whether circulation is being obstructed by atherosclerosis. Last winter Carlos Mastrangelo at the University of California, Berkeley, made a silicon light bulb, thinner than a hair, that could be fitted onto a hypodermic needle and paired with an optical sensor to “biopsy” a suspicious lump: tumors are less transparent to light than is healthy tissue. At a conference this February in Nara, Japan, Hirokazu Hotani of Teikyo University showed how a motor that mimics the whipsawing of bacteria tails can be regulated by electric pulses. “This could pave the way for a self-propelled exploratory machine running through the human body,” he says.
Whatever they do, many micromachines will need a motor. Since the first micromotor, .0001 of an inch across, was made at UC, Berkeley in 1988, the devices have achieved more than 15,000 rpm (car engines top out at about 7,000 rpm) and have run for nine months. Two months ago Mehran Mehregany of Case Western Reserve University unveiled polycrystalline silicon motors one fifth the size of the dot atop this “i.” He sees commercial applications in three to five years, perhaps powering little “Roto-Rooters” that chop up plaque on artery walls. “At this point, we’re still trying to understand the limitations of the technology, what is possible and what is not,” says Mehregany. The answers will depend on how micromachines wear, on how they react to forces that don’t matter at larger scales. To a motor this small, a speck of dust or a stray electric charge can look like a cannonball.
Late last year micromachines took their first steps out of the silicon age. Researchers at the University of Wisconsin, Madison, made the world’s smallest high-precision machine out of nickel. Since metals are less brittle than silicon, they promise more durable and perhaps more practical micromachines. To fabricate the tiny gears - several fit on a pinhead - the team led by Henry Guckel used X-ray lithography, akin to the technique used to etch integrated circuits onto computer chips (diagram). The UW craftsmen have made tiny gears, shafts, belts and pulleys, which may someday be configured into motors that will guide tiny rockets to distant worlds or power mini-robots searching the innards of nuclear power plants for cracks.
Engineers at Japan’s Agency of Industrial Science and Technology are on the trail of a power source for the tiny motors, which can’t exactly be plugged into the nearest outlet. Today’s micromotors run on static electricity: immobile “stators” arrayed around a circular motor are electrically charged and tug the motor’s gears, making them spin. Japanese scientists think they can use human glucose– blood sugar - to power the motors. Glucose would be oxidized between the tips of tiny electrodes, generating electricity. Such a battery could power “a drug-delivery capsule or an artificial pancreas,” says Fumio Mizutani of the science agency.
Although American science discovered this scientific Lilliput, the Japanese may colonize it. Last August Japan’s Ministry of International Trade and Industry chose micromachines for its next big “national effort” and announced that it will pour 25 billion yen (about $200 million) into a 10-year drive to research and develop industrial and medical microrobots. “Japan is behind the United States in this technology by about two years,” says CWRU’s Mehregany. “It won’t take long for them to surpass us.” If that happens, America will cede to Japan a technology more momentous than stereos: micromachines “cut to the core of our economic survival,” warns NSF’s Hazelrigg. NSF and the Defense Advanced Research Projects Agency together spend all of $2.5 million a year on micromachines. Private R&D, not very interested in products whose payoff is farther away than the next quarter kicks in a paltry $1.5 million to $2.5 million. At the Nara conference, not a single U.S. company presented a research paper; several Japanese firms did. “We’ve already lost the battle for chips,” says Stephen Jacobsen, director of the University of Utah’s Center for Engineering Design. “If we don’t learn how to produce things from the technologies we invent, we’re dead over the next two decades.”
While micromachines sound fantastic enough, to some scientists they are a mere way station on the road toward the ultimate discovery: a way to manipulate matter at the atomic level. As fans of nanotechnology (“nano” means billionths, as in billionths of a meter in size) ask, why bother to grow grass and feed it to a steer when you can assemble your own T-bone, amino acid by amino acid? Loony as it sounds, no laws of nature prohibit nanotechnology: the late Nobel physicist Richard Feynman showed how it is theoretically possible to fit all of human knowledge (24 million books, he figured) into a volume the size of a dust mote. (Represent letters as dots and dashes, each about five atoms long. As Feynman said, “Don’t tell me about microfilm!”) Today’s mini-gears and mini-motors can’t make a steak that never mooed, but they may become the guts of robots that will do anything else.
So far, micromachines do little more than spin around and mystify passing mites. But someday soon, they may be coming to a human body or a nuclear power plant, near you. Among the applications that micromachinists are dreaming up:
One chip holds a chemical sensor, valve, pump and reservoir. Implanted with a unit that monitored glucose and released insulin, a diabetic would not need daily injections.
Several labs have made motors smaller than a snowflake which, powering rotor blades, could travel through arteries, chopping up plaque in a real-life “fantastic voyage.”
Rather like Pac-Man, a chip armed with a special sensor and tiny tongs could swim around in contaminated well water gobbling up toxic pollutants.
ILLUSTRATIONS FOR NEWSWEEK BY JARED SCHNEIDMAN
X-rays or light shine through stencil-like mask onto a silicon chip. They hit a sensitive coating, leaving a very small gear-shaped pattern.
The silicon gear sits atop a sacrificial layer, usually made of a plastic. Silicon and sacrificial layers alternate.
The chip is immersed in an acid bath that dissolves the sacrificial layers. The gear is free to rotate.
title: “Welcome To Lilliput” ShowToc: true date: “2022-12-11” author: “Carole Ridling”
Think small. Very small. So small that a pair of tongs is dwarfed by a snowflake, motors and gears can hide beneath a fleck of dandruff, levers and springs are smaller than a grain of sand. And then think big. The revolution in microdevices represented by these tiny tools promises to do for machines what the incredible shrinking chip has done for electronics. Micromachines could include such wonders as gnat-size robots that pick out toxic chemicals from backyard wells. Medical researchers dream of pumps no bigger than the period at the end of this sentence that would float through the bloodstream straining out HIV-infected cells. “The greatest scientific frontier in this century is the microworld,” declares engineer Yotaro Hatamura of Tokyo University.
Calling the breakthroughs an advance in miniaturization is like dismissing the laser as a brighter light bulb. Microdevices promise a quantum leap beyond the abilities of normal machines because, starting with the first micros fashioned at Bell Labs in 1987, they are made of the same polysilicon and by the same techniques as computer chips. Thus a single chip can hold not merely a small machine, but a smart one, able to process information like any computer chip. And thousands can be made at once, dirt cheap. Colored specks on walls could be instructed to flip over to reveal a new hue when a homeowner wanted to redecorate. Mini-robots could pick out specks of gold from ore now too low-grade to bother with. “In 30 years,” says George Hazelrigg of the National Science Foundation, “this technology is going to be everywhere.”
The greatest advances may come in medicine, where micromachines could embark on a real-life fantastic voyage through the bloodstream. Polla’s device could continuously monitor levels of glucose and deliver insulin to a diabetic. At Pittsburgh’s Carnegie Mellon University, a rotor with blades no wider than three human hairs spins as blood flows through it; someday it may allow scientists to determine whether blood is being obstructed by atherosclerosis. Last winter Carlos Mastrangelo at the University of California, Berkeley, made a silicon light bulb, thinner than a hair, that could be fitted onto a hypodermic needle and paired with an optical sensor to “biopsy” a suspicious lump: tumors are less transparent to light than is healthy tissue. Last month, at a conference in Nara, Japan, Hirokazu Hotani of Teikyo University showed how a motor that mimics the whipsawing of bacteria’s tails can be regulated by electric pulses. “This could pave the way for a self-propelled exploratory machine running through the human body,” he says.
Whatever they do, many micromachines will need a motor. Since the first micromotor, .0001 of an inch across, was made in 1988, the devices have achieved more than 15,000 rpm (car engines top out at about 7,000 rpm) and have run for nine months. Last month Mehran Mehregany of Case Western Reserve University unveiled polycrystalline silicon motors one fifth the size of the dot atop this “i.” He sees commercial applications in three to five years, perhaps powering little “Roto-Rooters” that chop up plaque on artery walls. “At this point, we’re still trying to understand the limitations of the technology, what is possible and what is not,” says Mehregany. The answers will depend on how micromachines wear, on how they react to forces that don’t matter at larger scales. To a motor this small, a speck of dust or a stray electric charge can look like a cannonball.
Late last year micromachines took their first steps out of the silicon age. Researchers at the University of Wisconsin, Madison, made the world’s smallest high-precision machine out of nickel. Since metals are less brittle than silicon, they promise more durable and perhaps more practical micromachines. To fabricate the tiny gears - several fit on a pinhead - the team led by Henry Guckel used X-ray lithography, akin to the technique used to etch integrated circuits onto computer chips (diagram). The UW craftsmen have made tiny gears, shafts, belts and pulleys, which may someday be configured into motors that will guide tiny rockets to distant worlds or power mini-robots searching the innards of nuclear power plants for cracks.
Engineers at Japan’s Agency of Industrial Science and Technology are on the trail of a power source for the tiny motors, which can’t exactly be plugged into the nearest outlet. Today’s run on static electricity: immobile “stators” arrayed around a circular motor are electrically charged and tug the motor’s gears, making them spin. Japanese scientists think they can use human glucose - blood sugar - to power the motors. Glucose would be oxidized between the tips of tiny electrodes, generating electricity. Such a battery could power “a drug-delivery capsule or an artificial pancreas,” says Fumio Mizutani of the science agency.
Although American science discovered this scientific Lilliput, the Japanese may colonize it. Last August Japan’s Ministry of International Trade and Industry chose micromachines for its next big “national effort” and announced that it will pour 25 billion yen ($200 million) into a 10-year drive to research and develop industrial and medical microrobots. “Japan is behind the United States in this technology by about two years,” says CWRU’s Mehregany. “It won’t take long for them to surpass us.” If that happens, America will cede to Japan a technology more momentous than stereos: micromachines “cut to the core of our economic survival,” warns NSF’s Hazelrigg. NSF and the Defense Advanced Research Projects Agency together spend all of $2.5 million a year on micromachines. Private R&D kicks in a paltry $1.5 million to $2.5 million. At the Nara conference, not a single U.S. company presented a research paper; several Japanese firms did. “We’ve already lost the battle for chips,” says Stephen Jacobsen, director of the University of Utah’s Center for Engineering Design. “If we don’t learn how to produce things from the technologies we invent, we’re dead over the next two decades.”
While micromachines sound fantastic enough, to some scientists they are a mere way station on the road toward the ultimate discovery: a way to manipulate matter at the atomic level. As fans of “nanotechnology” (“nano” means billionths, as in billionths of a meter in size) ask, why bother to grow grass and feed it to a steer when you can assemble your T-bone amino acid by amino acid? Loony as it sounds, no laws of nature prohibit nanotechnology: Nobel physicist Richard Feynmann showed how it is theoretically possible to fit all of human knowledge (24 million books, he figured) into a volume the size of a dust mote. (Represent letters as dots and dashes five atoms long.) Today’s mini-gears and mini-motors can’t make a steak that never mooed, but they may become the guts of robots that will do anything else.
So far, micromachines do little more than spin around and mystify passing mites. But someday soon, they may be coming to a body, or a nuclear power plant, near you. Among the applications that micromachinists are dreaming up:
One chip holds a chemical sensor, valve, pump and reservoir. If the unit monitored glucose and released insulin, a diabetic with an implanted chip would never need another injection.
Several labs have made motors smaller than a snowflake which, powering rotor blades, could travel through arteries chopping up plaque in a real-life fantastic voyage.
Using the same principle as Pac-Man’s, a moving chip armed with a sensor and tongs could travel through contaminated well water plucking out toxic pollutants.
1 X-rays or light shine through stencil-like mask onto a silicon chip. They hit a sensitive coating, leaving a very small gear-shaped pattern.
2 The silicon gear sits atop a sacrificial layer, usually made of a plastic. Silicon and sacrificial layers alternate.
3 The chip is immersed in an acid bath that dissolves the sacrificial layers. The gear is free to rotate.
