UNSW develops medical submarines

Image Credit: An artist's representation of 'micro-submarines' transporting their medical cargo through capillaries among red blood cells. Picture: UNSW

University of New South Wales (UNSW) engineers have developed micrometre-sized submarines powered through nanomotors that can deliver medicine to cancer affected organs.

UNSW chemical and biomedical engineers say the technology can be used to design the next generation ‘micro-motors’ or nano-drug delivery vehicles, that apply novel driving forces to reach specific targets in the body.

“We already know that micro-motors use different external driving forces – such as light, heat or magnetic field – to actively navigate to a specific location,” said Dr Kang Liang, Corresponding author, with both the School of Biomedical Engineering and School of Chemical Engineering at UNSW.

“In this research, we designed micro-motors that no longer rely on external manipulation to navigate to a specific location. Instead, they take advantage of variations in biological environments to automatically navigate themselves.”

Liang says the micro-sized particles respond to changes in biological pH environments to self-adjust their buoyancy. This is significant for not only medical applications, but for micro-motors generally.

“Most micro-motors travel in a two-dimensional fashion,” said Dr Liang. “But in this work, we designed a vertical direction mechanism. We combined these two concepts to come up with a design of autonomous micro-motors that move in a 3D fashion. This will enable their ultimate use as smart drug delivery vehicles in the future.”

Liang says each capsules of medicine could contain millions of micro-submarines, and within each of those millions of micro-submarines would be millions of drug molecules.

“Once in the gastrointestinal fluid, the micro-submarines carrying the medicine could be released. Within the fluid, they could travel to the upper or bottom region depending on the orientation of the patient,” said Dr Liang.

“The drug-loaded particles can then be internalised by the cells at the site of the cancer. Once inside the cells, they will be degraded causing the release of the drugs to fight the cancer in a very targeted and efficient way.”

Dr Liang says the micro-submarines are essentially composite metal-organic frameworks (MOF) micro-motor systems containing a bioactive enzyme (catalase) as the engine for gas bubble generation.