Light-seeking algae might become the workhorses of the next generation of lab-on-a-chip devices, the Materials Research Society meeting in Boston heard last week. Labs-on-a-chip are used for medical and genetic analysis, and typically consist of arrays of microscopic wells containing chemicals that react with any biological cells that are added. Researchers are constantly on the lookout for better ways to get the cells to the right wells.
Water-borne Chlamydomonas algae are phototactic 鈥� they swim towards light if it is at a wavelength they can use for photosynthesis. Douglas Weibel, a chemist at Harvard University, wondered if he could harness 鈥渃hlamy鈥� motion to get the algae to shunt objects around.
He coated 1-micrometre-wide polystyrene beads with peptides that the alga likes to bind to and placed them at one end of an 18-centimetre-long microchannel. When Chlamydomonas were added, each alga bound itself to a bead. And when a light was switched on at the far end of the channel the algae moved towards it, dragging the beads with them.
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When they arrived, Weibel used a pulse of ultraviolet light to break the bond between the peptide and the bead ensuring the alga deposits its load. He now plans to investigate further the forces algae can produce and work out how to replace the beads with living mammalian cells.
PICK-AND-MIX ENTERTAINMENT
Few TV sets have enough separate sockets to plug in a digital TV tuner, DVD player, VCR, camcorder and games console. And with existing multi-way Scart connectors, the signals from different devices get mixed up, turning the picture into a distorted mess.
Bluedelta Design, based near Cambridge in the UK, has a smart solution. Gadgets are plugged into its multi-way device in order of preference, with the most-used gadget 鈥� the DVD player, say 鈥� in the top slot, and the least-used, perhaps the camcorder, in the bottom one. If a higher-priority socket is active, the Smart-Scart disables any lower-priority ones, so the TV set only receives one signal at a time.
Smart-Scart also allows an internal connection between two of its sockets, so you can set the VCR to record a TV programme, for example, while watching a DVD or playing a computer game.
