Scientists create tiny, caterpillar-like robot that could deliver drugs inside human body

Robot can move inside surfaces within the body to deliver drugs to where they're needed

Scientists have created a tiny, soft robot with caterpillar-style legs that could be used to deliver drugs in the human body.

Developed from research led by City University of Hong Kong, the mini delivery-robot could pave the way for medical technology advancement due to its ability to carry heavy loads and be adaptable to adverse environments.

Due to its design with multi-legs, which help to reduce friction, the robot can move efficiently inside surfaces within the body lined with, or entirely immersed in, body fluids such as blood or mucus, the researchers claimed.

There are hundreds of these legs, all less than 1mm long. The research team studied the leg structures of hundreds of ground animals including those with two, four, eight or more legs to come up with this design, in particular, the ratio between leg-length and the gap between the legs.

"Most animals have a leg-length to leg-gap ratio of 2:1 to 1:1. So we decided to create our robot using 1:1 proportion," explained Dr Shen Yajing, assistant professor at the University's Department of Biomedical Engineering, who led the research.

Controlled by a magnetic manipulator used in experiments, the robot can move in both a flap propulsion pattern and an inverted pendulum pattern, meaning that it can use its front feet to flap forward as well as swinging the body by standing on the left and right feet alternately to advance respectively.

"The rugged surface and changing texture of different tissues inside the human body make transportation challenging. Our multi-legged robot shows an impressive performance in various terrains and hence open wide applications for drug delivery inside the body," added Professor Wang, another researcher on the project.

The team further proved that when facing an obstacle ten times higher than its leg length, the robot, with its deformable soft legs, is capable to lift up one end of its body to form an angle of up to 90-degree and cross the obstacle easily. And the robot can increase its speed by increasing the electromagnetic frequency applied.

Laboratory tests showed that the robot was also capable of carrying a load 100 times heavier than itself, a strength comparable to an ant, one of the strongest Hercules in nature, or to a human being able to easily lift a 26-seated mini-bus.

"The amazingly strong carrying capability, efficient locomotion and good obstacle-crossing ability make this milli-robot extremely suitable for applications in a harsh environment, for example delivering a drug to a designated spot through the digestive system, or carrying out medical inspection," said Yajing.

Before conducting further tests in animals and eventually in humans, the research teams are developing and refining their research in three aspects, namely finding a biodegradable material, studying new shapes, and adding extra features.

"We are hoping to create a biodegradable robot in the next two to three years so it will decompose naturally after its meds delivery mission," Yajing added.