New micro-rocket will one day travel round your body fighting disease

In the 1980's one of the decade's most popular films was one called "Innerspace" where a team of scientists injected an amazing shrinking submersible directly into a poor individuals bloodstream and off it went to have adventures and fight disease and stomach acid.

Yeah yeah I know what some of you are thinking - the 1980's what the hell's that?! Anyway, for those of you that remember the 80's the good news is that soon you might be able to see another sci-fi concept become reality.

This week engineers from the University of Sheffield (UoS) in the UK announced that they've successfully developed a tiny microscopic rocket that they say could one day be injected into the human body to deliver medicine and even locate cancer and other indicators of disease.

Unlike many other small microscopic devices, such as the brain controlled, drug delivering nanobots that scientists have been using to deliver drugs to targeted areas within cockroaches; yes, you heard that right, now sit down, have a coffee, let the realisation that the world has changed wash over you and continue reading the article I've been sweating over for hours; what makes the new discovery from UoS unique is that fact that this, by all definitions is actually a micro-rocket.

The new micro-rockets are small, safe and cheap to make and they're built using an innovative inkjet 3D printer that mixes liquid silk with an enzyme - the secret behind the tiny rocket's thrust. When the enzyme infused structure is placed in a fluid along with hydrogen peroxide for fuel, the enzyme reacts, creating oxygen bubbles that propel the tiny vehicle forward. The researchers were able to control the trajectory of the rocket by altering the location of the enzyme.

"Most other miniature devices have typically been built using polystyrene beads, carbon nanotubes, or metals - substances that aren't very friendly to human tissue," says project manager Xiubo Zhao, "but the silk and enzyme structure of our micro-rocket is biocompatible. So unlike the macro-rockets that litter Earth's orbit with space junk, these micro-rockets can simply biodegrade inside you."

Great to know. Unfortunately for Innerspace fans though, the micro-rockets aren't quite ready for prime time. The hydrogen peroxide fuel used to create the rockets' thrust is toxic to humans, and then there's the issue of the rocket getting wedged somewhere - something noone wants. After all, try explaining how you managed to get a tiny rocket wedged somewhere private to a doctor...

A silk micro-rocket swimming in an aqueous hydrogen peroxide solution 

"... and you don't want all those oxygen bubbles inside the body either," says Zhao, "and even though the rockets are just 300 microns long and 100 microns in diameter that's still to big to be injected into a person because it could get lodged somewhere and cause trouble."

"Perhaps when 3D printing technology allows us to make nano sized rockets then perhaps it will be all systems go for in vivo launches," he adds.

Until then, micro-rockets may have applications outside the human body, such as testing for cancer cells in blood samples, Zhao says. Finding circulating cancer cells in blood can be tricky because there may only be a few per billion cells.

"Imagine you have a billion people and just ten of them are wanted criminals," Zhao says, using an analogy, "it's difficult to find them, right? But if you have a car driving around, it might be easier to catch these people."

Similarly, the micro-rockets could cruise around a blood sample tracking down other types of renegade cells. So there may be some important missions in the near future for micro-rockets - even if they can't blast off inside our bodies just yet.