By Laura Shin
Posting in Technology
What if a lab technician could take a single drop of blood, place it on a microchip and test for hundreds of diseases simultaneously? An innovation brings us closer to that vision.
Medical lab tests nowadays are so 20th century.
The technician takes a vial, or several vials, of blood. They ship them off to a lab. And though we're in the age of the Internet, you still have to wait a day or more to get the results.
What if, instead, the technician could take a single drop of your blood, place it on a microchip and run tests for hundreds of diseases all at once?
While labs on chips have been in the works for a while, they have not become widespread because they usually take a lot of money and time to make (i.e. $600 and half a day for one 6mm-squared chip). However, researchers at MIT have developed a new technique that is already up to 60 times cheaper and up to 100 times faster than traditional stamping methods required to create so-called biosensors.
The innovation, a glass stamp that can create tens of thousands of chips, is even more precise and can produce new chips more easily than existing technologies. The University of Illinois at Urbana-Champaign and the Massachusetts of Technology researchers published their methods in Nanotechnology.
How it works
In order to create the stamp, the researchers began with a syringe of melted glass composed partly of ions. They pressed it onto a master pattern to create a mold, which became the glass stamp.
After it cooled, they pressed the glass stamp onto the kind of metallic surface used for microchips and activated the stamp with a bit of voltage. The voltage stimulated ions both in the glass as well as the metal, essentially etching the glass pattern onto the chip.
They could then use this single stamp to etch tens of hundreds more labs on chips.
So how does the chip itself, which is now imprinted with tiny dots that are smaller than one-hundredth the width of a human hair, sniff out diseases in your blood?
The nano-sized dots act as "optical antennae" that read a specific wavelength to identify a single molecule. (Optical antennae are useful at nano scales because the length of a regular lightwave is too big for nano structures).
Improvements on existing biosensor manufacturing methods
The techniques currently being used to create these microchips are laborious and expensive. For instance, electron-beam lithography uses a beam of electrons to etch patterns on each individual chip. (This is the method that could take half a day to create one chip that would cost more than $600.)
Another method, nanoimprint lithography, is cheaper, but it uses a polymer to create a mold for the chip, and if the mold has imperfections, then all the copies will contain the same imperfections. (Though the new technique also uses a mold, the glass takes the shape of the mold more smoothly than the polymer.)
Nicholas Fang, one of the authors and an MIT mechanical engineering professor, says that their new technique takes several minutes to imprint one piece -- making it about 100 times faster than electron-beam lithography and up to four times faster than nanoimprint lithography.
He estimates that they could manufacture each chip for $10 now, but he projects that if they ever scale up, the cost could be comparable to that of DVDS: less than 10 cents each.
However, that day is yet to come. The initial process for creating both the master pattern and master glass stamp is expensive.
Still, Fang says:
With this stamp, I can reproduce maybe tens of hundreds of these sensors, and each of them will be almost identical. So this is a fascinating advancement to us, and allows us to print more efficient antennae.
photo: One of the stamped samples (Kyle Jacobs)
Oct 19, 2011