Painting With Molecules

Scientists at the Vienna University of Technology have created a novel way of fixing molecules precisely in three-dimensional material using laser beams, reports the university. Applications could include growing biological tissue or making tiny sensors.

The team’s Aleksandr Ovsianikov likened the development to the work of a painter: “Much like an artist, placing colors at certain points of the canvas, we can place molecules in the hydrogel–but in three dimensions and with high precision.”

But I get ahead of myself. What’s “hydrogel,” to begin with? TUW (to use the university’s German acronym) describes it thus: “a material made of macromolecules, arranged in a loose meshwork.” The researchers introduced certain molecules into this hydrogel meshwork, then zapped them with a laser beam. This would in turn cause a bond between the molecules that had been introduced and the hydrogel. Effectively, it allowed researchers to fix molecules right where they wanted them.

The researchers call this “3D-photografting.” It’s similar to 3D-printing, in that it allows you to place material just where you want it–and indeed, the researchers had developed new kinds of 3D-printers in the past. But the photografting technique, as should be evident from the description above, is actually quite different from 3D-printing. On such a small scale, and working with materials with different chemical properties, 3D-printing actually wouldn’t be helpful, Ovsianikov said.

This video reveals a 3D pattern the team was able to produce using the photografting technique.

Besides being cool, what’s the use of such a technique? Researchers say that matrices could be used to artificially grow biological tissue. By precisely positioning certain chemical signals in certain places, living cells entering the matrix could attach in the proper arrangement. The technique could also be used to create tiny 3D labs-on-chips. The fields of photovoltaics or sensor technology could also benefit, claims TUW.

For more on the development, see the recently-published paper in your favorite bedside read, Advanced Functional Materials.