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

NYU Offers Financial Aid to Undocumented Students

The Wall Street Journal reported that NYU will begin offering scholarship aid to undocumented students for the school year beginning next September.

NYU Adopts Lean LaunchPad Program to Teach Entrepreneurship

Startup guru Steve Blank, in a Huffington Post blog, described how NYU adopted the Lean LaunchPad model to teach entrepreneurship to students and faculty at NYU.

Biology Professor Jane Carlton Examines Wastewater for the City’s Microbiome

The New York Times’ Science Times column “Well” profiled Biology Professor Jane Carlton and her research project to sequence microbiome of New York City by examining wastewater samples.

Steinhardt Professors Use a Play as Therapy

The New York Times wrote about a play written by Steinhardt Music Professor Robert Landy about the relationship between Adjunct Professor Cecilia Dintino, a clinical psychologist in the Drama Therapy Program, and a patient, former Broadway actress Jill Powell.

NYU Public Health Experts Urge Strengthening Local Health Systems to Combat Ebola

Dean Cheryl Healton of the Global Institute of Public Health and Public Health Professor Christopher Dickey wrote an op-ed in the Huffington Post saying international health agencies need to strengthen their presence in countries at the local level to prevent future ebola outbreaks.

NYU Footer