Researchers in Japan have demonstrated one part of an envisaged molecular level system that might one day enable cell phones to keep a regular watch on their owners' health.

NTT DoCoMo hopes some future cell phones will contain "DNA chips," devices capable of analyzing molecules from the user's body, to provide a warning about a possible virus, high-levels of stress or other factors that might affect health.

But for the DNA chips to get the samples required, the molecules to be analysed must be transported into the phone from the user's body. This is where the latest research in so-called "molecular communications" comes in.

The work carried out by NTT DoCoMo and researchers at The University of Tokyo proved the feasibility of transporting a specific molecule between two set points using chemically-engineered motor proteins, said Shuichiro Ichikoshi, a spokesman for NTT DoCoMo in Tokyo.

Motor proteins are typically found in muscles and nerve cells and in the research they were depositied on a glass substrate in the chip to create paths to the DNA-chip. When a molecule arrives via the user's sweat the motor proteins transport it to the sensors for analysis.

The entire process requires no electrical or mechanical input or control so can work on its own.

The development is just one piece of the research required before such a system can be commercialized. NTT DoCoMo's Ichikoshi expects the entire system to be feasible in a laboratory about five years from now and not ready for commercial use for perhaps another five years after that.

NTT DoCoMo, which is more usually concerned with transporting of digital data across its cellular network, has been working on molecular communications for some time and previous research involved a program with the University of California.