Rapid New Process For Fabricating Microstructures From Protein

Jason B. Shear and Bryan Kaehr describe using the laser technique to fabricate detailed shapes — such as the silhouette of a housefly and the State of Texas — by condensing (or crosslinking) proteins in solution into a solid matrix. Their study is scheduled for the Feb. 28 issue of the Journal of the American Chemical Society, a weekly publication.

The researchers also used the process to fabricate minute 3-D structures, including 1- and 2-story microcontainers that were used to trap, incubate and grow as few as a single living bacterium into colonies. Such traps could have a variety of uses, including studying the formation of biofilms, which are the source of human health concerns.

The technique, mask-directed multiphoton lithography, is modeled after the photolithography processes widely used to transfer electronic circuits onto a semiconductor wafer by projecting light through a pattern or "mask."

However, the new method uses a special laser to scan objects or patterns printed on transparency film with an ordinary desktop printer. The silhouette ultimately is refocused into the protein solution using the objective lens of a microscope.

Because protein molecules must be extremely close to the laser focus to undergo crosslinking into solid material, this method allows structures to be created with complex 3-D shapes. The process takes only minutes, researchers report.