Scientists have developed microscopic "mucosal robots" smaller than a cell that can deliver drugs into the body by sneaking past immune defenses like a "Trojan horse."
Mucus acts as a sticky protective barrier against germs, but it can also make giving some medications more difficult because it traps drug molecules.
This mucus not only lines the nose, but also protects the lungs, stomach, intestines, and eyes by trapping pathogens.
Now, scientists have developed tiny robots with nano-mucus fueled by hydrogen peroxide, which can easily bypass the mucus barrier.
Using mice, scientists from the American Chemical Society have shown how their mucous robots can penetrate the sticky defensive layer of mucus and potentially deliver drugs more efficiently.
The robots are so small that 10 of them lined up together would only cover the width of a red blood cell.
Each robot is made up of porous particles that can be filled with drug molecules, helping the drugs sneak past the body's defense system like a Trojan horse.
The team attached catalase enzymes, a biological catalyst that speeds up chemical reactions in cells, to the robots. They then gave them to mice along with the mucus-dissolving hydrogen peroxide, which helped propel the mucus robots.
The team then built a model of the intestinal mucus layer, using human intestinal cells they had grown in the lab. Within 15 minutes, the tiny robots traversed the model's mucus layer without significantly damaging the cells underneath.
Given that mucus is cleaned and renewed every 10 minutes to 4.5 hours, this rapid time frame could prevent the robots from becoming trapped and removed by the mucus layer.
The scientists conducted further tests on the intestines of mice and saw similar results, with the nanorobots able to bypass the mucus layer without harming the cells and tissues underneath.
About 28% of the mucosal nanorobots were able to cross the mucosal barrier.
The scientists believe their robots are a promising way to deliver drugs that are normally blocked by the mucosal barrier.