Printing With Enzymes

Roland Piquepaille writes "Researchers at Duke University have developed a new printing technique using catalysts to create microdevices such as labs-on-a-chip. Their inkless printing technique uses enzymes from E. coli bacteria and has an accuracy of less than 2 nanometers. While they're are now using enzymes to stamp nanopatterns without ink, the research team is already working with non-enzymatic catalysts. And it added that 'future versions of the inkless technique could be used to build complex nanoscale devices with unprecedented precision.'"

Comments

Something smells fishy

[pesho]

Yet another scientific story with big claims and little detail. 2nM accuracy sounds a little overstated. First the polyacrylamide gel is elastic. Second they are using fluorescence to see the pattern and this at the very best has resolution of about 300nM. Third they need to generate the pattern on the stamp first and there is no mention in the article what is the accuracy of that. They seem to assume that the accuracy is equal to the DNA diameter.

And the cost is...

[mc moss]

I bet a cartridge of enzymes would still be cheaper than ink that printer companies sell us.

the actual reference...

[kebes]

Yet another scientific story with big claims and little detail. 2nM accuracy sounds a little overstated.

Indeed. The news release misses the point of the paper somewhat.

The actual scientific paper appears to be this one:
Phillip W. Snyder, Matthew S. Johannes, Briana N. Vogen, Robert L. Clark, and Eric J. Toone, "Biocatalytic Microcontact Printing" J. Org. Chem., 72 (19), 7459 -7461, 2007 DOI: 10.1021/jo0711541

Second they are using fluorescence to see the pattern and this at the very best has resolution of about 300nM.

They use confocal fluorescence which is, as you note, diffraction limited. However for the high-resolution study of the line-edges, they use Atomic Force Microscopy which is of course much higher resolution. The AFM images they show, however, appear to have rather imperfect line-edges, with resolution of >200 nm. Actually, nowhere in the paper do they claim to have demonstrated 2 nm resolution. Rather, they point out in the introduction that their new technique, in principle, could allow higher-resolution printing that conventional soft lithography, because there is no diffusion of reagents in their technique. The news release focuses on this mention of a theoretical 2 nm resolution, rather than pointing out the actual accomplishment of the paper, which in the words of the authors is:

In conclusion, we have demonstrated the feasibility of biocatalytic lithography. Catalyst-mediated soft lithographic technique offers the advantage of lateral resolution controlled by the range of motion of the immobilized catalyst rather than by the diffusive properties of molecular inks. This feature should facilitate the implementation of strategies for stamping nanoscale features. Further examination of stamping parameters and the application of this methodology to nanolithography are underway, and we will report our results in due course.

So, in short, it's an important advancement but the authors are not claiming to have achieved the intended ultra-high-resolution yet. And, even without that optimistic resolution, the technique is interesting in its own right because it is a new way to control the nanoscale chemical patterning of surfaces.