Micro-submarines may one day deliver medications inside the body

Engineers at UNSW have shown that it is possible to deliver medications directly to affected organs using tiny, self-propelled micro-submarines. The researchers have developed micrometer-sized submarines that exploit biological environments to tune their buoyancy to enable them to carry drugs to specific locations inside the body.Researcher Dr. Kang Liang says that the knowledge can be used to design next-gen "micro-motors" or nano-drug delivery vehicles to reach specific targets inside the body. Liang says that the micro-motor uses different external driving forces, such as light, heat, or magnetic field, to actively navigate to a specific location. The team, in this case, designed micro-motors that no longer rely on external manipulations to navigate to a particular site.

What makes the tiny creations the team has come up with unique is that they respond to changes in biological pH environments to self-adjust buoyancy. The scientist says that this is the same way a big submarine uses air or water to flood ballast tanks to make it more or less buoyant. The micro-motors can release gas bubbles, or retain them, in response to conditions inside human cells to move the nanoparticles up or down.

The work the team has developed resulted in the creation of a micro-motor that can move in three dimensions, rather than the two dimensions that micro-motors are typically able to move in. The team sees the invention being able to deliver medication into specific parts of the body to fight cancer.

The team says that a cancer patient could take a capsule filled with millions of micro-submarines with millions of drug molecules each tucked inside. The micro-submarines could release their drug payloads when they dump their drug-loaded particles that make their way inside the cells to fight cancer in a very targeted way. The team says that years of testing is still required before this treatment is available for humans.