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Remote-controlled cars for flies could unlock secrets of flight
Technology
SURGEONS about to perform delicate operations on the heart or major blood vessels need the clearest pictures they can get. Magnetic nanoparticles injected into the bloodstream will help reveal fine details on MRI (magnetic resonance imaging) scans – but there’s a snag. The particles quickly accumulate in the liver, which then removes them from the body. Now Mauro Magnani of the University of Urbino in Italy and his team have found a way to get the tiny particles to spend longer in the bloodstream, by hiding them inside living red blood cells. To do this, the team first immerse the blood cells in a watery solution, which causes them to swell. This opens pores in their membranes, allowing nanoparticles to drift into the cells. They become trapped when
Computer game for flies could unlock secrets of insect flight
HOW does a fly fly? Exactly how the insects control their flight, using only a few hundred neurons, is a bit of a mystery. But now roboticists are hoping to work out how they do it - using a system that lets fruit flies “drive” a remote-controlled car. First, a fruit fly is tethered to a rod 26 | NewScientist | 4 October 2008
into patients’ bloodstreams, and red blood cells have been used as drug delivery vehicles in several thousand people with no serious side effects so far. If the procedure is used, only a small fraction of a person’s red blood cells will carry the particles, Magnani points out. Mohammed Hamady, a consultant radiologist at Imperial NHS Trust in London, says the technique could be particularly useful for monitoring patients after treatment to patch up an aortic aneurysm, a swelling in the wall of the largest artery in the body. Blood sometimes leaks out from the repair, and this can be difficult to detect. “This technique could help us to follow the flow of the blood,” he says. In a separate study, Magnani added fluorescent particles to red blood cells which make them glow –Signs of a healthy retina– when exposed to infrared light. This allowed him to image the movement of individual blood visualise the circulatory system. cells through capillaries at the back Magnani has already used magnetic blood cells to image the of the eye in monkeys and rabbits (Investigative Ophthalmology hearts of mice. “We can see the and Visual Science, DOI: 10.1167/ circulatory system, the heart and iovs.07-1504). Measuring the speed the heart cavities,” he says. He is now working with Philips Research at which blood flows through these capillaries could help diagnose in the Netherlands to establish conditions such as diabetic whether a similar procedure can retinopathy and age-related safely be used in humans. The macular degeneration, which can nanoparticles are already lead to blindness. Linda Geddes ● approved for direct injection THOMAS DERRINCK/NCMIR/SPL
Nanomagnets in disguise help fill in the detail
the cells are returned to a solution more like blood and the pores close up again (Journal of Nanoscience and Nanotechnology, DOI: 10.1166/jnn.2008.190). When the treated cells are injected back into the bloodstream, they remain there until they are destroyed naturally, which normally takes about four months. During this time, the nanoparticle payload can be used to help
with a cylindrical LED display around it. The display shows geometric patterns that are known to make a fruit fly move left or right - a kind of virtual reality simulator for flies. Since the fly is tethered, it can’t actually move, but it tries to anyway. “The fly’s pretty dumb,” says roboticist Brad Nelson, who created the “flyborg” with colleagues at the Swiss Federal Institute of Technology Zurich. The patterns on the display are triggered by images transmitted from a camera mounted on a miniature robotic car. If the car approaches an obstacle, the display shows the appropriate pattern and the fly reacts accordingly. As it does so, another camera detects minute changes in the movements of its wings. “We measure the lift force and
kinematics in real time,” says Nelson. This information is then sent back to the robotic car as instructions that tell it which way to steer in order to avoid the obstacle. The process is repeated every time the car looks like it’s going to crash into something, and has been successfully used to
“The fly’s movements guided a remote-controlled car through a forest of pillars” pilot the car as it whizzes through a forest of pillars. While isolated neurons have previously been used to control a robot’s movements, studying an entire organism’s movements should help the researchers develop an
understanding of how flies can perform complex manoeuvres using relatively little brain power. Nelson’s team ultimately plans to build up a complete computational model of a fly’s neural network by systematically knocking out the genes that encode for flight-control neurons in real flies and using the simulator to see how these changes affect behaviour. The technology might eventually be used to control a flying robot, such as the miniature fly-like devices created by Robert Wood at the Harvard Microrobotics Laboratory in Cambridge, Massachusetts although Wood points out that any control system would still have to be made small enough to fit into the robot fly. Duncan Graham-Rowe ● www.newscientist.com
SURGEONS about to perform delicate operations on the heart or major blood vessels need the clearest pictures they can get. Magnetic nanoparticles injected into the bloodstream will help reveal fine details on MRI (magnetic resonance imaging) scans – but there’s a snag. The particles quickly accumulate in the liver, which then removes them from the body. Now Mauro Magnani of the University of Urbino in Italy and his team have found a way to get the tiny particles to spend longer in the bloodstream, by hiding them inside living red blood cells. To do this, the team first immerse the blood cells in a watery solution, which causes them to swell. This opens pores in their membranes, allowing nanoparticles to drift into the cells. They become trapped when
Computer game for flies could unlock secrets of insect flight
HOW does a fly fly? Exactly how the insects control their flight, using only a few hundred neurons, is a bit of a mystery. But now roboticists are hoping to work out how they do it - using a system that lets fruit flies “drive” a remote-controlled car. First, a fruit fly is tethered to a rod 26 | NewScientist | 4 October 2008
into patients’ bloodstreams, and red blood cells have been used as drug delivery vehicles in several thousand people with no serious side effects so far. If the procedure is used, only a small fraction of a person’s red blood cells will carry the particles, Magnani points out. Mohammed Hamady, a consultant radiologist at Imperial NHS Trust in London, says the technique could be particularly useful for monitoring patients after treatment to patch up an aortic aneurysm, a swelling in the wall of the largest artery in the body. Blood sometimes leaks out from the repair, and this can be difficult to detect. “This technique could help us to follow the flow of the blood,” he says. In a separate study, Magnani added fluorescent particles to red blood cells which make them glow –Signs of a healthy retina– when exposed to infrared light. This allowed him to image the movement of individual blood visualise the circulatory system. cells through capillaries at the back Magnani has already used magnetic blood cells to image the of the eye in monkeys and rabbits (Investigative Ophthalmology hearts of mice. “We can see the and Visual Science, DOI: 10.1167/ circulatory system, the heart and iovs.07-1504). Measuring the speed the heart cavities,” he says. He is now working with Philips Research at which blood flows through these capillaries could help diagnose in the Netherlands to establish conditions such as diabetic whether a similar procedure can retinopathy and age-related safely be used in humans. The macular degeneration, which can nanoparticles are already lead to blindness. Linda Geddes ● approved for direct injection THOMAS DERRINCK/NCMIR/SPL
Nanomagnets in disguise help fill in the detail
the cells are returned to a solution more like blood and the pores close up again (Journal of Nanoscience and Nanotechnology, DOI: 10.1166/jnn.2008.190). When the treated cells are injected back into the bloodstream, they remain there until they are destroyed naturally, which normally takes about four months. During this time, the nanoparticle payload can be used to help
with a cylindrical LED display around it. The display shows geometric patterns that are known to make a fruit fly move left or right - a kind of virtual reality simulator for flies. Since the fly is tethered, it can’t actually move, but it tries to anyway. “The fly’s pretty dumb,” says roboticist Brad Nelson, who created the “flyborg” with colleagues at the Swiss Federal Institute of Technology Zurich. The patterns on the display are triggered by images transmitted from a camera mounted on a miniature robotic car. If the car approaches an obstacle, the display shows the appropriate pattern and the fly reacts accordingly. As it does so, another camera detects minute changes in the movements of its wings. “We measure the lift force and
kinematics in real time,” says Nelson. This information is then sent back to the robotic car as instructions that tell it which way to steer in order to avoid the obstacle. The process is repeated every time the car looks like it’s going to crash into something, and has been successfully used to
“The fly’s movements guided a remote-controlled car through a forest of pillars” pilot the car as it whizzes through a forest of pillars. While isolated neurons have previously been used to control a robot’s movements, studying an entire organism’s movements should help the researchers develop an
understanding of how flies can perform complex manoeuvres using relatively little brain power. Nelson’s team ultimately plans to build up a complete computational model of a fly’s neural network by systematically knocking out the genes that encode for flight-control neurons in real flies and using the simulator to see how these changes affect behaviour. The technology might eventually be used to control a flying robot, such as the miniature fly-like devices created by Robert Wood at the Harvard Microrobotics Laboratory in Cambridge, Massachusetts although Wood points out that any control system would still have to be made small enough to fit into the robot fly. Duncan Graham-Rowe ● www.newscientist.com