Blood cell-size computer memory

US researchers have created an ultra-dense memory device the size of a white blood cell that has enough capacity to store the Declaration of Independence and still have space left over.

The accomplishment represents an important step toward the creation of molecular computers that are much smaller and could be more powerful than today's silicon-based computers.

‘Using molecular components for memory or computation or to replace other electronic components holds tremendous promise,’ said J. Fraser Stoddart, who holds the chair in Nanosystems Science at UCLA and is director of the California NanoSystems Institute.

The 160,000 bits are arranged like a large noughts and crosses grid. 400 silicon wires are crossed by 400 titanium wires, each 16 nanometres wide, with a layer of dumbbell-shaped molecular switches sandwiched between the crossing wires.

‘This research is one of the only examples of building large molecular memory in a chip at an extremely high density, testing it, and working in an architecture that is practical, where it is obvious how information can be written and read,’ Stoddart said.