ThomasJoined: January 30, 2007Status: OfflinePosts: 94Rep:
The use of bacteria for micro-technologies Thu Feb 1, 2007 4:02:29 AM#33313Perm Link
Bacteria, and more precisely Serratia marcescens, had already been used as micro-pumps to push fluid through capillaries. This bacterium sticks naturally to the surface of a glass chip, and a concentrated colony was used to form a "bacterial carpet" with their flagellum free to move and set the surrounding fluid in motion. The speed of this micro pump could be adjusted with the temperature or the addition of glucose.
Now, a research team went even further and used S. marcescens to propel micro-objects through water. The bacteria were this time stuck to micro-beads (10 microns in diameter) of polystyrene and placed in an aqueous solution of glucose. Fuelled by glucose, the movement of the flagella allowed those beads to achieve the speed of 15 microns/second. The system could be switched on or off very simply, and an indefinite number of times. The addition of copper sulfate to the solution stopped the flagellum through the binding of the copper ion to the motor, whereas adding EDTA (ethylenediaminetetraacetic acid) restarted it though chelation of these copper ions.
Harnessing entire micro-organisms as engines for micro-robots is both simple, as no purification is necessary, and easily controlled, as they are naturally sensitive to their environment. This method could be inexpensively used in the future to deliver drugs with micro-robots into liquid parts of the human body, like the urinary tract, the eyeball cavity, the internal ear, or the cerebrospinal fluid. These tiny robot can also be used in the monitoring of toxic or pathogenic biochemicals in the environment, or even for the inspection and maintenance of liquid-filled capillaries in spacecraft and nuclear plants, said the head of the research team.
This is of course far remote from the famous science-fiction films Fantastic Voyage or Inner Space, were submarine-like crafts were miniaturised with their crew in order to enter a human body, but this is an extremely important step in the advance of micro- and even nano-technologies.
There were links, but I haven't got them anymore. The original paper was published in the Journal Of Applied Physics if I remember correctly, and there was also a short article in the New Scientist. Sorry, I can't tell you more than that... :S