快猫短视频

IF YOU want to create artificial organs or a sophisticated biosensor, Bradley
Ringeisen has just the thing. Think of it as a laser-powered pen that uses
biological cells for its ink supply.

There are several ways to deposit thin layers of cells needed to build
artificial organs. But arranging the materials in precise patterns is tough. So
Ringeisen, a physical chemist at the Naval Research Laboratory in Washington DC,
decided to see if he could exploit a laser deposition technique he鈥檇 been
working on鈥攆or making chemical weapons sensors鈥攆or laying down
precise patterns of cells.

NRL鈥檚 technique, called matrix-assisted pulsed-laser evaporation direct write
(MAPLE-DW), uses a laser to transfer materials onto a surface. First, Ringeisen
prepares the cells or other biomaterials by suspending them in a viscous liquid.
He then freezes a layer of the mixture onto a small quartz disc, and fires a
laser through the rear of the disc, focusing the laser at the interface with the
frozen sample. A computer controls the focusing, drawing the desired pattern of
cells.

Heat evaporates the frozen sample, propelling cells onto a surface about 50
micrometres away. 鈥淲e think it is going to be a revolutionary technology,鈥� says
Ringeisen. If MAPLE-DW could place cells of different types next to each other
in a three-dimensional array, the technology could create artificial joints and
organs. By depositing cells on plastics, silicon and glass, it could be used to
make biosensors that combine living cells with circuitry.

Ringeisen is now working with the National Cancer Institute in Gaithersburg,
Maryland, to adapt the laser technique for creating sensors based on ordered
arrays of tissue. These would let tissues from different organs be tested
simultaneously to see how they respond to drug therapy.