Micro-robots capable of manipulating human cells are no more than a year away, scientists have claimed.

The micro-robots, dubbed nanotools, have been developed by California-based Innovation On Demand to be operated wirelessly by focused beams of energy. They will be able to control objects as small as 100 nanometres across.

Predicted uses of the micro-robots would be for drug discovery, construction and control of medical devices such as valves and microsurgical instruments, and the manipulation of proteins and genetic components.

"Innovation On Demand was just granted a US patent that provides broad claims about what the device can be used for, including both therapeutic and diagnostic uses inside the human body," said Lynn Yoffee, associate publisher of NanoBiotech News, in a statement.

The so-called 'microactuators' use special metal alloys that return to a 'memory' state when heated.

They eliminate the need for chips, batteries, and other bulky devices, allowing for devices that can be miniaturised to the low-micron range.

When a scanning electron microscope or a laser heats up the shape-memory alloy elements in the micro-robots, it allows them to grip and manipulate nanoscale objects.

A single scanning electron microscope could control multiple micro-robots engaged in biomedical and biotechnological research, nano-manufacturing and other uses, according to Ken Clements, chief executive at Innovation On Demand.