Nanotechnology with microscopic grippers

The chief investigator, David Gracias
The chief investigator, David Gracias
Microgripping at nanolevel
Microgripping at nanolevel

 

Isaac Asimov's science fiction classic, Fantastic Voyage, depicted five people travel in a submarine inside a person's blood stream and that was fiction.  But today, scientists are really into replicating every observation of the science fiction of the yesteryears in making it a reality.

The most recent and highly innovative invention was the announcement made by the American Chemical Society with the creation of microscopic robotic devices that act like small hands inside a host organism.

David Gracias, assistant professor at the Institute for Nanobiotechnology, JohnsHopkinsUniversity, and colleagues noted that researchers have long sought to develop chemically triggered microscopic devices that can manipulate small objects with precision. David Gracias and colleagues noted the need to develop chemically triggered microscopic devices that could manipulate small objects with precision.  Gracias, born in India, received a Ph.D. in chemistry at University of California, Berkeley. He was a post-doctoral fellow with George Whitesides at Harvard and worked as a senior engineer in R&D at Intel Corporation before his current position. 

He studied chemical actuation which is part of every biological machinery and which  enables autonomous function in nature with high specificity and selectivity. Earlier scientists had manufactured robotic experimental “grippers” in the lab, however these devices generally required the use of batteries and wiring, making them hard to miniaturize and maneuver in small spaces and convoluted conduits.
Gracias and his group of researchers describe the development of tiny metallic microgrippers shaped like hands that work without electricity. The grippers are about 0.03 inches wide when open, smaller than the diameter of a grain of sand and made from a gold-coated nickel “palm” joined by six pointy metallic “fingers.” The addition of certain chemicals triggers the hands to open or close. Laboratory studies demonstrate that the grippers can grasp and release tiny pipes and glass beads and transport these objects to distant locations with the aid of a magnet.   These chemically actuated microgrippers have potential for pick-and-place operations that are ubiquitous utility in manufacturing.
The microgrippers are a step toward the development of Micro Chemo Mechanical Systems (MCMS) in contrast to the already well established field of Micro Electro Mechanical Systems (MEMS); the main difference being that the tools are triggered by chemistry as opposed to electricity. The chemically triggered microscopic 'hands' can manipulate particles smaller than a grain of sand, which can be used in lab-on-a-chip applications and micro-manufacturing.   Although other  experimental "grippers"  were attempted they  required the use of batteries and wiring, making it  difficult to manouevre them in small convoluted spaces. Researchers describe these tiny metallic microgrippers, shaped like a hand are about 0.03 inches wide when open - smaller than the diameter of a grain of sand and made from a gold-coated nickel "palm" joined by six pointy metallic "fingers".  They work without electricity and certain specific chemicals trigger the hands to open or close.  Scientists have demonstrated that the grippers can not only grasp and release tiny pipes and glass beads but also transport these objects to distant locations with the aid of a magnet.  They are capable of lifting small pieces of metal, or other objects, and transporting them where they are most needed. The devices are not powered by batteries via wiring but their  actions are triggered by chemical signals,  which makes their operation more sensitive and specific. The grippers can navigate sinuous places inside living bodies, without causing damage.  The micro grippers, are capable of operating using chemical actuation properties and reactions identical to the biological interactions in the human body. The micro machines are built on a very small scale,  and each of them measures only 0.03 inches (0.76 millimeters) when they are opened

The basic construction principle of the robot is a gold-coated nickel “palm,” complete with 6 metallic fingers, which can be closed at the command of a specific chemical activator. All actions that the machines perform are ordered via specifically-designed chemicals, which ensure that there are no mechanical confusions in the process, and that the robot doesn't grip instead of releasing, or vice-versa.
The surface-chemistry-driven actuation is realized in high-surface-area materials such as nanoporous gold. The effect is explained with  adsorbate-induced changes of the surface stresswhich  converts chemical energy directly into a mechanical response, thus opening the door to surface-chemistry-driven actuator and sensor technologies.  The technology of microrobotics is already making Asimov’s fantasy of swimming robots in the bloodstream a reality.

 

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