Snot might not be the first place you’d expect nanobots to be roaming around. However, this slimy substance is not limited to just your nose; it also plays a crucial role in protecting various parts of the body such as the lungs, stomach, intestines, and eyes. Researchers have successfully showcased in mice that their microscopic, enzyme-fueled ‘snot bots’ can navigate through the sticky protective layer to potentially enhance drug delivery efficiency.
Snot, scientifically known as mucus, acts as a protective barrier by trapping pathogens and irritants. Yet, this same protective function can hinder the effectiveness of locally administered drug treatments. Scientists like Samuel Sánchez and his team devised a strategy to enhance drug delivery by creating nanoscale robots powered by mucus-dissolving hydrogen peroxide (H2O2).
The nano-robots, comparable in size to just ten lined up red blood cells, were constructed by attaching catalase enzymes to porous silica nanoparticles. These nanoparticles can be filled with drug molecules, aiding them to navigate through the mucus layer like a Trojan horse. Initial experiments revealed that when coupled with H2O2, the catalase enzymes enabled the bots to move forward by breaking down the peroxide fuel into oxygen and water.
In a subsequent experiment, the team simulated the intestinal mucus layer using lab-grown human intestinal cells. Within 15 minutes, the bots successfully crossed the artificial mucus layer without causing substantial harm to the underlying cells. Given that mucus is typically refreshed every 10 minutes to 4.5 hours, this rapid transit time may prevent the bots from being trapped or eliminated by the mucus layer. Further assessments on mouse colons supported these findings, demonstrating that the nanobots traversed the dense layer without damaging cells or tissues. The study revealed that around 28% of deployed nanobots effectively penetrated the mucus barrier, representing a 60-fold enhancement compared to passive particle diffusion. Previous studies using different enzymes or mucus-disrupting drugs had only improved diffusion by around 10-fold. The researchers are optimistic about the potential of their ‘snot bots’ as drug delivery systems, particularly for medications hindered by the mucus barrier.
The study received financial support from various entities including the European Research Council, the State Research Agency, “ERDF A way of making Europe,” the European Union NextGenerationEU/PRTR (Bots4BB project), the CERCA program by the Government of Catalonia, the Ministry of Research and Universities, the Department of Business and Knowledge of the Government of Catalonia, and the Severo Ochoa Center of Excellence.
