This is SAW (Single Actuator Wave-Like Robot). Dr. David Zarrouk designed and tested this innovative 3D printed robot at Ben-Gurion University in Israel. The SAW uses a wave-like motion to propel itself over rough terrain, swim through water, and even climb up vertical walls. The SAW could be used as a reconnaissance vehicle, an inspection device for tunnels and sewers, and even a medical device capable of exploring your stomach and intestines because of its versatility.
How It Works
The SAW uses a central helix surrounded by a 3D printed spine to achieve its wave-like motion. The helix is derived from a 2-dimensional sine wave projected onto a third dimension that can then be 3D modeled and printed. The helix spins inside the spine and creates the wave-like motion that is so versatile. Dr. Zarrouk has invented robots before that move like worms but never one this simple. With only a single motor this design is about as minimalistic as one can get. Being simple means that it is relatively maintenance free. It also means that it’s easy to scale down. The smallest version Dr. Zarrouk made was 12 cm (about 5 in) long, but they can be made much smaller.
What It’s For
The main purpose of this machine was always medical. Colonoscopies currently can only reach the large intestines. This is fine if the issue is in the large intestine. But what if the problem is in the small intestine? Currently there is not good method for inspecting the small intestine. Pill cameras can passively capture footage over 24 hours of the small intestines, but they can’t be directed or told to go back and look at something. They can also get stuck and run out of battery leaving the doctor with video of only half an intestine.
The SAW could not only greatly reduce the amount of time it is in the body; it can target specific areas thought to be problematic and view it at multiple angles. Imagine you were trying to take a picture of a flower. The pill camera is a bullet train with you on it. You have no control over the speed and can only snap a picture if you time it perfectly. If you don’t get it there’s no way to turn the train around and try again. The SAW is a minivan. You can slow down or even stop and get out to take as many pictures as you need until you get a good one. The level of detail the SAW will allow doctors to achieve will greatly increase the chance of a proper diagnosis.
Looking To The Future
Let us for a moment look ahead to the future of this technology. There are only two main parts to SAW robots: the motor and the body. Tufts University chemists created a molecule wide motor several years ago, and the Karlsruhe Institute of Technology (KIT) in Germany has machines that can 3D print features as small as 30 nanometers. With these two technologies, one could make a SAW that’s so small it can traverse human veins and arteries.
Dr. Charles Sykes and his team at Tufts University placed a butyl methyl sulfide molecule on a conductive copper surface. The molecule had carbon and hydrogen atoms attached like two arms and could rotate around the sulfur copper bond. Using a low-temperature scanning tunneling microscope the team was able to observe consistent and controllable rotation at temperatures of around -450 degrees Fahrenheit. At higher temperatures, the motor spun so fast they couldn’t collect any meaningful data from it. “Once we have a better grasp on the temperatures necessary to make these motors function, there could be real-world application in some sensing and medical devices” said Dr. Sykes.
Nanoscribe, the company that sells the micro 3D printers designed by KIT, has created a new printer that is up to 100 times faster than their old technology. It is capable of printing details nanometers across using two-photon polymerization. The process is similar to SLS printing but on a molecular scale. The printer pulses near-infrared lasers on a single point of a light sensitive material, again much like the resin used in SLS printer, and the material solidifies at that point. The structure is formed by repeating this process over and over. Until now the light sensitive material was mechanically moved in three dimensions to determine where the lasers focus was. With the new machine, however, mirrors are used to direct the laser beams focal point to the correct location, drastically decreasing print time.
Combining these cutting-edge technologies, we could be looking at a 3D printed SAW able to travel almost anywhere inside out bodies. Doctors could autopsy brain tumors without picking up a scalpel, diagnose ulcers previously unreachable, or simply study the microscopic anatomy that we’ve never been able to see before.