Feynman Prize for Experiment: Christian Schafmeister

Now speaking is Christian Schafmeister of U. Pittsburgh. His career started in computers, then went to bio, now on to chemistry. He’s been at the chemistry for five years.

First slide shows an Aldrich chemical catalog and the productive nanosystems cover story from C&E News. His goal is to get from one to the other. Now he’s telling us that he’s done protein engineering and it’s incredibly frustrating to engineer these materials. He decided to start over with more traditional chemistry to make building blocks. He makes building blocks with different shapes but that connect together in the same way: four different pro4 bis-amino acid monomers, made from stereochemically pure molecules available from Aldrich: “cheap”. “Pedestrian chemistry.” Very important that these connections NOT be single bonds, because that makes the final products too flexible and floppy. Need multiple bonds to get the stiffness needed to make the structures he’s aiming at. He does a lot with controlled stereochemistry (i.e. the “handedness” of a molecule). He uses NMR to make sure that what has been made is what was desired, plus at least two other techniques, since the NMR is limited in what it tells you.

More fun: now he’s showing the rapid computer-aided design of these structures: 20,000 structures per second can be analyzed. Now he’s showing an expanded tookit of building blocks, needed to make compact structures, with pockets. Applications: molecular spintronics, peptide receptors and sensors for small molecules. Long term goals: maskless array synthesis of thousands of machine parts; pick and place assembly of complex machines.

Question from audience: make branching building blocks? Answer: gets very hard, not sure there are enough protecting groups to do it. Question: can these be crystallized? Answer. not yet. Question: non-local cross-linking as a problem? Answer: it’s not a problem. Do the bis-protein denature? Ans: They shouldn’t, I don’t expect them to denature because they are fused ring systems, should take 150 degrees, and also vacuum. Q: Self-replication? A: Incredibly complex problem, I don’t think so. I don’t really worry about it. We don’t need self-replication for advanced nanotech.

For more on why he won the Prize, see the press release. Apologies to Chris for errors in the summary above. —Christine

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