New York University Skip to Content Skip to Search Skip to Navigation Skip to Sub Navigation

Crystal Mysteries Spiral Deeper, Chemists Find

December 11, 2013

By James Devitt

NYU chemists have discovered crystal growth complexities, which at first glance appeared to confound 50 years of theory and deepened the mystery of how organic crystals form. But appearances can be deceiving.

Their findings, which appeared in the Proceedings of the National Academy of Sciences, have a range of implications—from the production of pharmaceuticals and new electronic materials to unraveling the pathways for kidney stone formation.

The researchers focused on L-cystine crystals, the chief component of a particularly nefarious kind of kidney stone. The authors hoped to improve their understanding of how these crystals form and grow in order to design therapeutic agents that inhibit stone formation.

While the interest in L-cystine crystals is limited to the biomedical arena, understanding the details of crystal growth, especially the role of defects—or imperfections in crystals—is critical to the advancement of emerging technologies that aim to use organic crystalline materials.

Scientists in the Molecular Design Institute in the Department of Chemistry have been examining defects in crystals called screw dislocations—features on the surface of a crystal that resemble a spiraled ham.

Dislocations were first posed by William Keith Burton, Nicolás Cabrera, and Sir Frederick Charles Frank in the late 1940s as essential for crystal growth. The so-called BCF theory posited that crystals with one screw dislocation would form hillocks that resembled a spiral staircase, while those with two screw dislocations would merge and form a structure similar to a Mayan pyramid—a series of stacked “island” surfaces that are closed off from one another.

Using atomic force microscopy, the NYU team examined both kinds of screw dislocations in L-cystine crystals at nanoscale resolution. Their results showed exactly the opposite of what BCF theory predicted—crystals with one screw dislocation seemed to form stacked hexagonal “islands,” while those with two proximal screw dislocations produced a six-sided spiral staircase.

A re-examination of these micrographs by Molecular Design Institute scientist Alexander Shtukenberg, in combination with computer simulations, served to refine the actual crystal growth sequence and found that, in fact, BCF theory still held. In other words, while the crystals’ physical appearance seemed at odds with the long-standing theory, they actually did grow in a manner predicted decades ago.

“These findings are remarkable in that they didn’t, at first glance, make any sense,” says chemistry professor Michael Ward, one of the authors of the study. “They appeared to contradict 60 years of thinking about crystal growth, but in fact revealed that crystal growth is at once elegant and complex, with hidden features that must be extracted if it is to be understood. More importantly, this example serves as a warning that first impressions are not always correct.”

The research was supported by the National Science Foundation and the NSF Materials Research Science and Engineering Center Program.


Type: Article

Crystal Mysteries Spiral Deeper, Chemists Find

Search News



NYU In the News

Paying It Backward: NYU Alum Funds Scholarships

The Wall Street Journal profiled Trustee Evan Chesler on why he decided to chair the Momentum fund-raising campaign.

A Nobel Prize Party: Cheese, Bubbles, and a Boson

The New Yorker talked to Professor Kyle Cranmer and graduate student Sven Kreiss about NYU’s role in the discovery of the Higgs boson, which resulted in a Nobel prize for the scientists who predicted its existence.

The World as They Knew It

The New York Times reviewed the exhibit at the Institute for the Study of the Ancient World on how ancient Greeks and Romans mapped the known and unknown areas of their world.

Elite Institutions: Far More Diverse Than They Were 20 Years Ago

NYU made stronger gains over the last 20 years in increasing diversity than any other major research university, according to the Chronicle of Higher Education.

Program Seeks to Nurture ‘Data Science Culture’
at Universities

The New York Times reported on the multi-million collaboration among NYU and two other universities to harness the potential of Big Data, including an interview with Professor Yann LeCun, director of NYU’s Center for Data Science.

NYU Footer