The approach used by three universities conflates magnetic fields and robotics to transport drugs across human body.

Robotics is a technology, heavily explored by the healthcare sector. Due to its robust system, it has become the most desired and favored technology for medical inputs in the 21^st century. From introducing the first robot 'da vinci' for performing the general surgical procedures to incorporating robots for assisting the patients, diagnosing the disease, and performing laboratory procedures, robotics has expanded the scope of medical care. The global healthcare robotics market is expected to grow from US$11.4 billion by 2020. A report by PwC states that surgical robots own the largest contribution for the robotics-driven healthcare market. Additionally, a report by the Frost & Sullivan points out that the global 'robots for personal care' market could reach US$17.4 billion by 2024.

Purdue University

In a potential breakthrough, the researchers at Purdue University have created tiny bots that can travel across human body through tumbling. The research paper titled "A Tumbling Magnetic Microbot System for Biomedical Applications" is published in MDPI.

The research paper states that the robotic system comprises of untethered magnetic microbot, a two-degree-of-freedom rotating permanent magnet, and an ultrasound imaging system for in vitro and in vivo biomedical applications. The tiny robot functions through an external magnetic field so that it can safely penetrate different mediums across different organs. The researchers cite that the microrobot tumbles end-over-end in a net forward motion due to applied magnetic torque from the rotating magnet. By turning the rotational axis of the magnet, two-dimensional directional control is possible and the microrobot gets steered along various trajectories, including a circular path and P-shaped path.

David Cappalleri, a Purdue associate professor of mechanical engineering states, "When we apply a rotating external magnetic field to these robots, they rotate just like a car tire would to go over rough terrain. The magnetic field also safely penetrates different types of mediums, which is important for using these robots in the human body."

The research is initially carried out in mice for transporting medicines to the colon, where the robot is used as a drug-transport tool. Through this, the drugs get directly delivered to the desired organ, without penetrating other organs, thus eliminating adverse reaction or side-effects due to drugs.   The research paper states that the microrobot is capable of moving over the unstructured terrain within murine colon in vitro, in situ, and in vivo conditions, as well as a porcine colon in ex vivo conditions.

Additionally, high-frequency ultrasound imaging allows for real-time determination of the microrobot's position while it is optically occluded by animal tissue. The robot is coated with a fluorescein payload, to release the majority of the payload over a 1-h time period in phosphate-buffered saline. The tests such as Cytotoxicity which were performed to determine the adverse affects of robots on human body, did not show a statistically significant difference in toxicity to murine fibroblasts from the negative control, even when the materials were doped with magnetic neodymium microparticles. Furthermore, when seeded with murine fibroblasts, all material variants of the microrobot exhibited cell proliferation, with no statistically significant difference in toxicity compared to the negative control sample collected by the researchers. Hence, the microrobot system's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.

Researchers say that this approach can be used to perform minimally invasive procedures, where the target location is far from the point of entry.

Ohio State University and Georgia Tech

However, this is not the first time that microbots were incorporated into human body for performing biomedical procedures. Researchers from the Ohio State University and the George Institute of Technology have discovered a way through which tiny robots can transport across human body for treatments of colon polyps, stomach cancer, and aortic artery blockages. The study titled, "Untethered Control of Functional Origami Microbots with Distributed Actuation", is published in the proceedings of the National Academy of Sciences. Researchers have created a soft robot made with magnetic polymer, a soft composite material embedded with magnetic particles that can be controlled remotely.

Reena Zhao, the corresponding author of the paper and assistant professor of Mechanical and aerospace engineering states, "The robot is like a small actuator, but because we can apply magnetic fields, we can send it into the body without a tether, so it's wireless. That makes it significantly less invasive than our current technologies."

She further adds, "In biomedical engineering, we want things as small as possible, and we don't want to build things that have motors, controllers, tethers, and things like that.  And an advantage of this material is that we don't need any of those things to send it into the body and get it where it needs to go."

Researchers cite that the soft origami robots have the capability to conduct multiple treatments, while independently controlling the folding and deploying of the origami units. The origami units unfurl and release the drugs at the necessary site of the body. Though the research is not performed in the human body, the researchers are positive that this approach will allow the doctors to perform minimally invasive procedures through robotics.

Conclusion

Minimally invasive procedures are the most favored surgical approach among healthcare professionals. However, due to limited resources, this area has been less explored by scientists and experts. Additionally, earlier the scope of the magnetic field in medicine was confined to conducting MRI and CT-scan. By integrating the magnetic field with robotics, researchers have opened the doors for surgical procedures.