Sweating the small stuff Home

The Fantastic Use Of Atoms, One At A Time

by Lucy Komisar
American Reporter Correspondent
New York, N.Y.

LaBAULE, France - Man-made muscles that contract like biological ones but that are 100 times stronger, that are so powerful, they can inject drugs without a needle.

An external skeleton that conforms to the skin and kicks in when a weak knee or ankle kicks out.

Clothing made of cooling materials that amount to a personal air conditioning system.

The vibrator in a cell phone.

Ah, the last doesn't seem so extraordinary. But they're all built on the new nanotechnology that is using microscopic inventions to interact with the human body, to transmit information in and out, to give it strength or comfort.

Ian Hunter and Lynette Jones, scientists at the Massachusetts Institute of Technology, who are also husband and wife, work in nanotechnology. Nano is Greek for dwarf. This "molecular manufacturing" involves the manipulation of individual atoms. Small is not only sometimes better, it is extraordinary.

Hunter runs the Bioinstrumentation Lab at MIT which builds scientific instruments and nanorobots required to generate objects that are even smaller. Jones works with heptics - it comes from the Greek word hepticide, to touch - which uses the skin as the receptor for information that can't be delivered to eye or ear. Both systems are part of the revolution of "nanotechnology."

They discussed their work at a recent gathering of Forum 21 (http://www.forum-21.com/), an annual conference of Americans and Europeans held in France to talk about the latest in science, politics and culture. The conference was started in 2001 by Paul Weinstein and Abby Hirsch Weinstein, Americans living in Paris. He is president of Rive Droite International Investments and she is a journalist. The Forum met this spring in LaBaule, on the coast of Brittany

Hunter's lab creates biomimetic materials - things that are like living tissue but are not built out of proteins but conducting polymers. [Biomimetic: Imitating, copying, or learning from nature to make artificial products that mimic the natural ones.] He said, "We're trying to create the building blocks of artificial life forms, new materials with life-like characteristics. We've created muscle-like materials that can contract like muscle but are 100 times stronger than real muscle. We've created the equivalent of neurons that take signals from the brain to cause these artificial muscles to contract, and we've created centers for energy storage."

Out of those materials come structures that imitate human organs. "We've produced simple artificial lung forms out of these materials," He said, "equivalent to what nature might have produced a couple of thousand million years ago - very primitive life forms made out of these wonderful and bizarre materials. We've produced a reflex loop where we have an artificial muscle, a link sensor, a force sensor, some wires and the equivalent of a spinal neuron acting as a reflexive loop as a simple illustration of something with a primitive life-like capability."

The goal is not simple to produce objects in the traditional way, by creating and assembling parts, but to get the materials to actually grow. The materials are designed using molecular techniques that never existed before. Hunter said, "We're almost at a point where we can conceive of a machine that would start growing these artificial life forms that would have the equivalent of muscles and sensors and other functionality."

The new structures are built by nanowalkers - small robots that can literally crawl over and manipulate atoms. They can move by ten to the minus 11 of a meter, smaller than the size of an atom. Hunter said, "The nanowalker walks around with subatomic precision. We have developed 20 different nanowalkers to do different tasks. One might bring a small amount of chemical from one location to another. Another might do a measurement or extract something. Collectively they are implementing engineering tasks."

Rather than have components separately manufactured, the new products will be co-fabricated, as are humans and other living systems. Nanotechnology is developing manufacturing techniques to grow intelligent systems in three dimensions out of high molecular weight materials that provide more freedom to design important properties.

For example, Hunter said, "If you look at the motors that contract and generate force, which is what muscle does, if you look across nature, the maximum force used by nature almost doesn't change. Whether you're looking at a shellfish or a horse, there's a particular force that's generated. We've succeeded with artificial materials where we're generating 100 times more force than what nature created. We have invented new molecules; when you activate them with a small voltage they contract and generate gigantic force."

"The artificial muscle we've created is in early stages being used as heart assist material, in early experiments to create artificial bladders, sphincters, and recently for a new method of injecting drugs without using a needle. We've got a material that can contract with such enormous force, it can squirt out a drug at high velocity to go straight through the skin without the need for a needle."

He predicted that within the next five years, there will be clothing made of materials that can cool the skin, so you'll wear your air conditioning system!"

Talk of skin moves us to the specialty of Lynette Jones, who deals with heptics, using the skin actively in the exploration of the world.

Touch just involves passive contact, she explains. Heptics brings in the communication of knowledge through the skin. For example, when you pick up a glass, you have an immediate impression about the stiffness and compliance of the glass. It's a rigid object, it doesn't compress. So you won't try to crush it. You also know the force you need to generate from the fingertips so that the glass doesn't fall from your hand. If you lose some of the sensors in your fingertips from nerve disease or with old age, you have to deliberately increase that force.

Jones explained that the skin is a remarkably sophisticated medium, with 12 or 13 different sensors that respond to different sorts of inputs. Some respond to contact, or to the acceleration or the movement of an object in the hand, or to movement of the hair on the hand. The skin has receptors for cooling and warming and pain. She said, "One of the challenges in heptic displays is to make use of those sensory pathways to present information to the human operator."

A crass demonstration of something you can use on a daily basis is vibratactile input - the vibrator in cell phones.

People may be in situations where they can't see or hear something they are manipulating, or they may have visual and auditory system overload.

Jones explained, "In a lot of applications in space, military, and medicine, you have a lot of things you are monitoring visually; you may have a lot of auditory cues coming in. You have a relatively unused medium of the skin, about 1.8 sq meters of it sitting there." She said it seems a waste not to use the large number of neural connections from the skin to the central nervous system, from the spinal cord to the brain.

So displays are built to enable people to interact with computer-generated virtual environments and robotic systems. One of the large growth areas is in medically-operated robotic systems, particularly in endoscopic tools, where surgeons working with long detectors lose the sense of touch. They can't feel the presence of a lump in soft tissue, they can't feel viscous forces in the liquid medium they are moving through.

Jones explained, "So we want to present on these tool tips something about the operative environment, about the mechanical properties and materials in that environment."

"We work on displays that are hand-based or torso-based in which you can find information about the environment, as you move through it," she said. "For example if you're a medical resident doing some practice for a surgical procedure, you can thread the catheter through a virtual environment presented on a computer screen. You can feel and make contact by a series of actuators in a handheld object and you know when you're pushing against the wall of an artery. You may feel the palpations associated with the fact you are near a blood source. You wouldn't see these things visually."

Just what do you put on the tip of an instrument to make the surgeon "feel"?

Hunter said, "If I want to create a tactile display, we have a sheet of material like cloth that has millions and millions of muscle-like activators that contract and vibrate or perturb or manipulate the skin."

Other new medical devices that are wearable have systems that monitor medical cells through the skin, then analyze the data in blocs of time and transmit information if it has diagnostic significance.

Heptics is important also on a much larger scale. Jones said, "In tally operation, remote operation - you see that in construction in the international space station and undersea work - it's important to have mechanical cues in order to control the robot effectively. If you can't see the object you're manipulating - the robotic arm - if you have heptic feedback, then you can get a much better understanding of how you are manipulating the object, where it is in space and what it's moving."

One can put displays on the bodies of pilots to provide directional or fuel information. She explained, "If you're a fighter pilot and you want personal orientation, we can activate these with a series of motors on your skin to say 'this is a vertical,' or we can activate them to say 'go left, go right'." The device becomes a private communication source to enable one to keep oriented in an environment in which the sense of orientation is disturbed.

Why does this work? Jones explained, "The skin is extremely sensitive in picking up vibrations and very small irregularities in surface structure. For that it is superior to the eye. If you look at the acuity of the skin, how sensitive it is, it's remarkable that we can detect with the finger tip a 1 to 3 micrometer dot on a smooth surface about 500 micrometers wide. Visually you would see nothing on that glass surface, but if you move your fingertip over it, you can pick up these asperities in the surface. If it's a repeating pattern, so the same dot reappears at various points on the surface, we can get down to the mimometer level. And that is just with the bare skin."

She said, "It's also superior to the eye in terms of its processing of information in time. The best sense for temporal resolution is the air; that processes information on the order of .01 milliseconds. For the hand it's about 5 milliseconds, for the eye it's about 25 milliseconds."

Perhaps the most extraordinary use will unite Jones' research with Hunter's. She predicts using new materials as actuators for older people who lose range of motion and have weaker muscle power. They will wear an extra skeleton that is flexible and confirms to the skin. "So," she said, "when you generate 30 degrees of knee or ankle flex, that can exaggerate it so you can continue to walk and support your body."

Lucy Komisar welcomes your comments. Please send them to mailto:lkomisar@echonyc.com.