A dash of this, a pinch of that, and it seems researchers at Northwestern have cooked up a new class of nanostructures that aren't just ideal for such applications as gas storage or medical technologies, but also edible. The team, which began their research with a completely different outcome in mind, found that their recipe produced natural and edible metal-organic frameworks (MOFs), porous crystalline structures with unique properties that are usually difficult to make and composed of toxic petroleum products.
MOFs are tiny lattice-like crystals that contain a lot of free space for the storage of things like hydrogen gas molecules (like in a fuel cell, say). MOF tech has been around for more than a decade, but they are usually made from chemicals that are derived from crude oil. They aren't particularly easy to make and once produced they aren't easy to dispose of due to their toxic nature. But it turns out a starch molecule leftover from corn production will do the trick as well.The NU team set out to experiment with different molecular architectures based on a compound called gamma-cyclodextrin, a sugar ring produced from biorenewable cornstarch. But it turns out that with a little sugar and some alcohol you can turn gamma-cyclodextrin into a MOF structures as harmless as the ingredients therein.
Previous attempts at producing natural MOFs have failed largely because crystalline structures like MOFs require symmetry that is difficult to achieve with natural compounds. But gamma-cyclodextrin, itself containing asymmetric glucose residues, is arranged in a symmetric ring orientation. Dissolved in water with potassium salt and crystallized with alcohol -- the NU recipe calls for the grain spirit Everclear, a favorite at college campuses everywhere -- and you've got an MOF that's edible if not particularly tasty.
"They taste kind of bitter, like a Saltine cracker, starchy and bland," Ronald A. Smaldone, a postdoctoral fellow at Northwestern and co-author of the paper describing the research, said in a press release. "But the beauty is that all the starting materials are nontoxic, biorenewable and widely available, offering a green approach to storing hydrogen to power vehicles."
Sounds pretty tasty to us.