Common fruit flies, or Drosophila melanogaster, are the workhorses of modern genetics — we know its genes better than we do our own. They are also delicate little insects small enough to sit inside the edges of a freckle. So, using fruit flies in genetics research means countless hours in a lab full of undergrads gently grasping these little bugs with tweezers, recording standard measurements almost robotically.
Now robots can take over.
Reporting ahead of print in the journal Nature Methods, Joan Savall and a team of scientists out of Stanford demonstrate that much of the tedium that goes along with studying this model organism can be automated.
Created with parts totaling less than $5,000, this robotic fruit fly surgeon can identify fly sex, analyze fly size and shape, perform injections, and yes, drill into fruit fly brains.
The robot selects its patients in pitch blackness using infrared light. First, the scientists attach a vial of fruit flies to the robot rig, and then a small hole is opened to them. They climb upwards into the dark, exploring a plate above which the robot’s tiny suction needle or “picking effector” waits. Then, using both a stationary infrared camera and a moveable infrared camera near the effector, the robot projects a tiny ring of light onto a fly’s thorax, allowing it to track the fly’s movement. Using a series of infrared flashes, the robot goes in not for the kill, but the attachment.
By using a suction device, the robot has a big advantage over other, more tedious methods — no fruit flies need to be euthanized before study. In fact, the authors claim that the robot is both precise and gentle enough to grab a fly’s less than one millimeter across thorax, analyze it with cameras, subject it to testing, and release it to be studied again. Other methods need to at least anesthetize fruit flies before handling, and then need to wait for the flies to recover (lest the knock-out drugs make the flies behave unnaturally).
The other advantage is speed. Stanford’s fly rig can autonomously measure and catalog around 1,000 Drosophilia specimens within 10 hours. Can you imagine the army of undergrads needed to accomplish the same rate?
Perhaps most impressively, the robot can hold and transfer flies with suction devices while performing experiments like the effect different odors have on movement (GIF above) and conducting brain surgery (image above). The robot is dexterous and delicate enough to insert tiny fiber optics into fruit fly brains for neuron imaging after removing a drill with a bit smaller than a human skin cell (a,b,c above).
The entire apparatus also has the benefit of being scalable, meaning that the speed and precision the robot provides could increase dramatically depending on the set-up.