Scientists at the University of Colorado Boulder developed a new class of microrobots , which can move rapidly in liquids. Their goal is to use them in the future to deliver drugs inside the human body.

“Imagine if microrobots could perform certain tasks in the body, such as non-invasive surgeries,” said Jin Lee, lead author of the study and a postdoctoral fellow in the Department of Chemical and Biological Engineering.

“Instead of making incisions on the patient, we could simply introduce the robots into the body via a pill or injection and they would perform the procedure themselves.”

Of course, this development has not yet arrived, but innovation is a huge step forward.

The group’s microrobots are only 20 micrometers wide, a few times smaller than the width of a human hair, and can move at about 3 millimeters per second, or about 9,000 times their length per minute.

During the study, the team successfully used groups of these machines to deliver doses of dexamethasone, a common steroid drug, into the bladders of laboratory mice.

“Microscale robots are getting a lot of excitement in the scientific community, but what makes them interesting for us is that we can design them to perform useful tasks in the body,” said C. Wyatt Shields, co-author of the new study and assistant professor of chemical and biological engineering.

The microrobots are made from materials called biocompatible polymers using a technology similar to 3D printing.

Treatment of bladder diseases

The little machines have been tested against a common problem for humans: bladder disease.

They tried to bring relief to those suffering from interstitial cystitis, also known as painful bladder syndrome, through laboratory experiments in which scientists created flocks of microrobots with high concentrations of dexamethasone.

They injected thousands of these bots into the bladders of laboratory mice and observed how they were distributed throughout the organs and adhered to the walls of the bladder, which should make it difficult for them to exit through the urine.

The machines then began to gradually release their dexamethasone over a period of about two days, allowing patients to receive more medication over a longer period of time.

Despite the successful test, the team still needs to do a lot of work before the microrobots can navigate real human bodies, such as making the machines fully biodegradable so that they dissolve in the body over time.

Alexander Antipov, editor-in-chief of Securitylab.ru, believes that the study by Colorado scientists demonstrates the potential of microrobots for targeted drug delivery inside the human body. This direction of development of biomedicine has a number of advantages over traditional methods of treatment, such as systemic chemotherapy or nanoparticles. Microrobots can actively move through fluids and tissues, overcome obstacles and pressure gradients, and deliver drugs to the right places with high accuracy and efficiency. In addition, microrobots can be controlled from a distance using magnetic fields or other stimuli, allowing their speed, direction and timing of drug release to be controlled.

Microrobots for targeted drug delivery have been an active area of ​​research in recent years. Different types of microrobots have been developed for different purposes and applications. According to Alexander, in 2020 xenobots were created – microrobots from biological tissues without the use of metal and electronics. They have the advantages of biocompatibility and biodegradability over traditional micro robots. In 2021 there were presented soft microrobots, which can roll over uneven surfaces and deposit substances at precise locations in neural tissue. They have shown the ability to climb slopes, move against fluid flow, and perform complex manipulations. In 2022 there were amphibious microrobots invented , which can float in liquid and deliver drugs to organs. They are able to independently choose different modes of movement and switch between them by changing the magnetic field.

Microrobots for targeted drug delivery represent a promising technology for the treatment of various diseases, especially cancer, cardiovascular and neurodegenerative diseases. Antipov notes that a number of issues need to be addressed before they can be used in humans, such as safety, biocompatibility, biodegradability, efficacy, stability, standardization, and regulation. It is also necessary to conduct more clinical trials in animals and humans to confirm the effect and the absence of adverse reactions. In addition, it is necessary to develop new methods for the synthesis, characterization and control of microrobots to increase their functionality and adaptability.