Shrinking robots allows them to carry out ever more delicate tasks. But even the smallest built so far are too big to be able to, say, imprint microscopic, or even nanoscale, patterns onto microchips.
Now Jan Liphardt, a physicist at the University of California, Berkeley, and colleagues, say it may be possible to create new species of slave bacteria to do the job instead.
The idea is to create stripped-down versions of bacteria, with only enough of a genome to perform certain tasks - for example, swimming along a chemical trail using their flagella, secreting another chemical as they go.
The team describes how thousands of such "biobots" - or minicells - could carve out the kind of microscopic features needed on microprocessors, or gene chips used to test for millions of specific DNA sequences at once.
Biobots might be created using similar techniques to those being used by Craig Venter to create simple artificial cells of his own design.
They would be controlled using light of a specific frequency. Varying the amount of light would switch the biobots on or off by activating pigments carried by the mini workers.
But like more normal-sized robots, biobots could be entertaining too, the patent says. People could race them around tracks, mazes, or obstacles. They might even compete in biobot war games, trying to track each other down and making a kill by secreting antibiotics.
Such contests would depend on finding an easy way to make the tiny gladiators easier to see, perhaps by making them luminous, the patent notes.