Korean researchers have successfully demonstrated knee cartilage regeneration by using stem cells delivered by a magnet-controlled microrobot, raising hope to broaden a non-invasive procedure for patients who need invasive knee replacement surgery.

The new method can also raise stem cell delivery accuracy efficiency by up to 95 percent compared to less than 20 percent in pervious injection-dependent surgery.

A joint research group of scientists from the Korea Institute of Medical Microrobotics (KIMIRo), Chonnam National University Hospital and BIOT Korea announced on Sunday that they developed a stem cell navigator, a microrobot designed to deliver therapeutic stem cells to a target area, and succeeded in knee cartilage regeneration in a rabbit by using the robot.

This is the world’s first microrobot demonstration for knee cartilage regeneration in a live animal, and research details were published in the Science Robotics journal on Jan. 22.

The stem cell-mounted microrobot can deliver stem cells selectively to the damaged knee cartilage, enabling treatment with a single injection, and this will greatly reduce cost, time and patient burden, said Dr. Park Jong-oh, head of KIMIRo and a mechanical eng. professor at Chonnam National University, and the corresponding author of the research paper.

The robot has a structure of porous and biodegradable polymer-based particles with a diameter of 350 micrometers each. The magnetic ferumoxytol particles hold human fat-derived stem cells and nutrients and precisely deliver them to the damaged cartilage in response to an external magnetic field, and then the particles are gradually decomposed in the human body after treatment. Ferumoxytol is authorized by the U.S. FDA for the treatment of anemia. In the animal trial, knee cartilage regeneration was achieved in three weeks.

The researchers are planning to conduct additional animal tests in pigs and monkeys with an aim of launching a clinical trial within three years.