Wheel of life: bacteria provide horsepower for tiny motor.For millennia, people have hitched beasts to plows to exploit the animals' strength and energy. In a modern variant of that practice, scientists have chemically harnessed bacteria to a micromotor so that they can make the device's rotor slowly turn.
The new work might lead to improved lab-on-a-chip devices and engines to propel microrobots, says Yuichi Hiratsuka, now of the University of Tokyo “Todai” redirects here. For the restaurant called Todai, see Todai (restaurant).
The University of Tokyo (東京大学 , who codeveloped the bacteria-powered micromotor. He and his colleagues describe the research in an upcoming Proceedings of the National Academy of Sciences The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. .
The novel micromachine "is an important step in integrating biological components into microengineered systems," comments bioengineer William O. Hancock of Pennsylvania State University Pennsylvania State University, main campus at University Park, State College; land-grant and state supported; coeducational; chartered 1855, opened 1859 as Farmers' High School. in University Park.
To make the motors, Hiratsuka's team, led by Taro Q.P. Uyeda of the National Institute for Advanced Industrial Science and Technology in Tsukuba, Japan, borrowed fabrication techniques from the microelectronics industry.
The machinery of each motor consists of two parts: a ring-shaped groove etched into a silicon surface, and a star-shaped, six-armed rotor fabricated from silicon dioxide silicon dioxide: see silica.
(SiO2) A hard, glassy mineral found in such materials as rock, quartz, sand and opal. In MOS chip fabrication, it is used to create the insulation layer between the metal gates of the top layer and the silicon elements below. that's placed on top of the circular groove. Tabs beneath the rotor arms fit loosely into the groove.
To prepare the bacterial-propulsion units, the team used a strain of the fast-crawling bacterium Mycoplasma mycoplasma
Any of the bacteria that make up the genus Mycoplasma. They are among the smallest of bacterial organisms. The cell varies from a spherical or pear shape to that of a slender branched filament. mobile that was genetically engineered to crawl only on a carpet of certain proteins, including one called fetuin. The researchers laid down fetuin within the circular groove and coated the rotor with a protein called streptavidin.
The scientists then coated the micro-meter-long, pear-shaped bacteria with a solution containing biotin biotin: see vitamin; coenzyme.
Organic compound, part of the vitamin B complex, essential for growth and well-being in animals and some microorganisms. , a vitamin that readily binds to streptavidin.
The team released the treated bacteria into the grooves in a way that sent them mostly in one direction around the circle. As the microbes passed each of a rotor's supporting ridges, their biotin-treated cell membranes clung to the streptavidin coating, causing tugs on the tabs and thereby turning the rotor.
Slow and weak, the rotors circle at about twice the speed of the second hand on a watch and generate only a ten-thousandth as much torque as typical electrically powered micromachines do. By using more bacteria, the scientists could boost the torque 100-fold, Hiratsuka predicts.
In earlier work, many specialists in biologically inspired micromotors--including Uyeda's group--used components of cells, such as filaments called microtubules Microtubules
Slender, elongated anatomical channels in worms.
Mentioned in: Antihelminthic Drugs (SN: 10/27/01, p. 268), to devise microscale systems that transport objects.
Other teams have also used complete, living microbial microbial
pertaining to or emanating from a microbe.
the breakdown of organic material, especially feedstuffs, by microbial organisms. cells to drag tiny loads (SN: 8/20/05, p. 117) or to move fluids.
By using whole microbes as machine components, the Japanese team "adds a new direction to our field," comments biomolecular-motor specialist Henry Hess of the University of Florida University of Florida is the third-largest university in the United States, with 50,912 students (as of Fall 2006) and has the eighth-largest budget (nearly $1.9 billion per year). UF is home to 16 colleges and more than 150 research centers and institutes. in Gainesville.
"The micromotor system points the way to self-sustaining and self-repairing machines, since the active units ... can multiply and replace each other," he adds. "Living machines rock!"