In a further step to improve nanobot’ technology to fight cancer, a flagellated non-pathogenic strain of bacterium E.coli carrying extraneous DNA sequence was used to establish communication between nanobots within the blood stream of cancer patients in a computer simulation.

Nanobots are machines that contain several viable bacteria containing all the required information for combating tumor cells. Scientists were faced with the task of achieving a collaborated effort using several nanobots as single nanobot are inadequate to defeat cancer.

Single nanobot that swarms to the target tumor cells has to communicate to other nanobots in the vicinity. It does so by releasing the correctly encoded bacteria that are attracted to the nutrients contained in other nanobots. The E.coli swim to other nanobots and its encoded DNA's message is realized by binding with the chemical receptors on receiving nanobots. The DNA contains all the necessary information required for swarming and release of drugs.

Maria Gregori and Ignacio Llatser at the Polytechnic University of Catalonia in Barcelona, Spain used computer simulations to determine the time taken for the transfer procedure. According to them, E.coli encoded with 300,000 basepairs long DNA sequence equal to 600 kilobits of information will take 6 minutes to traverse a distance of 1 mm.

"That's a bandwidth of 1.7 kilobits per second. It's not high, but for the biomedical applications we envisage it should be [fast] enough," Llatser says.

Being a simulation result, this calculation has faced criticism from other experts who want experimental support to believe in the working of this technology.

"While their simulation results seem OK, only experimental evidence will convince me that their technique is working," says famous simulation expert Andrew Adamatzky who works with slime moulds, from University of the West of England in Bristol, UK.

Bacteria can successfully transfer information across a distance of few millimeters between two blood vessels. Other techniques like radio signals and pheromones fail in comparison to this methodology. Radio signals cannot travel through a liquid interface. Small chemicals like pheromones and calcium ions are effective only over large or microscopic distances.

In future, this research team from Spain predicts that nanobots will be able to sense tumor cells and release the anti-cancer drugs.