January 13, 2017

These tiny microrobots could be the future of medicine

Using a form of biocompatible materials known as hydrogels, a team of engineers led by Sam Sia of Columbia University has developed a way to fabricate microscale machines which could be safely implanted in the body and used to administer chemotherapy and other drugs.

According to Science News Journal, Sia’s team developed a “locking mechanism” that allowed these hydrogel microbots to have freely moving, three-dimensional parts, making it possible for them to function as drug delivery systems, valves, pumps, and rotors in the body.

As the study authors detailed in a recent edition of Science Robotics, these machines are made using a new additive manufacturing technique that stacks the soft material in layers. By doing so, they were able to tweak the biomaterials to have a variety of different mechanical properties and could maintain control over them after implantation.

Furthermore, their breakthrough allowed the system to operate without the need for a potentially harmful sustained power supply. In a test of the unit’s payload delivery system in a bone cancer model, it was found to deliver high treatment efficacy over the course of 10 days while reducing the toxicity of the chemotherapy to just one-tenth of its normal level.

Devices take 30 minutes to build, could safely deliver drug treatments

Overall, Sia explained in a statement, the so-called implantable microelectromechanical system or iMEMS device “enables development of biocompatible implantable microdevices with a wide range of intricate moving components that can be wirelessly controlled on demand.” It also helps to solve “issues of device powering and biocompatibility,” he continued.

“We’re really excited about this because we’ve been able to connect the world of biomaterials with that of complex, elaborate medical devices,” added Sia, a biomedical engineering professor at Columbia as well as a member of the Data Science Institute. “Our platform has a large number of potential applications, including the drug delivery system demonstrated in our paper which is linked to providing tailored drug doses for precision medicine.”


The left image: fabrication of support structures and assembly of gear components. The right: complete device after the layers have sealed. (Image Credit: SauYin Chin/Columbia Engineering)

When constructing the iMEMS device, the researchers began by using light to polymerize sheets of gel, then used a stepper mechanization to pattern each layer of the sheets by controlling the z-axis. This allowed them to manufacture composite structures within each layer of hydrogel while also managing their thickness during the entire fabrication process. Since they were able to stack multiple, precisely-aligned layers, the entire platform was completed in less than 30 minutes.

Unlike most currently-used implantable microdevices, the new iMEMS units have moving parts instead of static components and do not require batteries to power them. They also communicate wirelessly, according to the authors, and can be ordered to trigger payload releases days or even weeks after being implanted.

“These microscale components can be used for microelectromechanical systems, for larger devices ranging from drug delivery to catheters to cardiac pacemakers, and soft robotics,” said Sia. “People are already making replacement tissues and now we can make small implantable devices, sensors, or robots that we can talk to wirelessly. Our iMEMS system could bring the field a step closer to developing soft miniaturized robots that can safely interact with humans and other living systems.”


Image credit: Sau Yin Chin