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The Chemistry Department is pleased to announce that Brown University will award Professor Christopher Seto the Philip J. Bray Award for Excellence in Undergraduate Teaching in the Physical Sciences for 2012-2014. Professor Seto will be honored at the University's Teaching Awards Ceremony hosted by the Sheridan Center on Monday, May 7th at Pembroke Hall, Room 305. The ceremony reception begins at 4:00pm with the awards program kicking off at 5:00pm. Congratulations Professor Seto!

The Advisory Board of the Sheridan Center is delighted to announce the winners of the 2011 Harriet W. Sheridan Award for Distinguished Contribution to Teaching and Learning at Brown University. 

The Sheridan Award Medal will be presented to two extraordinary faculty: Professor Arnold Weinstein (Comparative Literature)and Professor Matthew Zimmt (Chemistry) on Monday May 7, 2012 at the annual University Awards Ceremony to be held at 5:00 PM at Pembroke Hall, Room 305. 

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A new process for assembling iron-platinum nanoparticles on graphene could lead to robust, effective catalysts for fuel cells (J. Am. Chem. Soc., DOI: 10.1021/ja2104334). The resulting materials made by Brown University chemist Shouheng Sun display up to nine times higher catalytic activity in laboratory tests, and are more stable, than commercial platinum catalysts. (read more)

A team in the US has created a boron compound that has the highest coordination number of any planar species, squeezing 10 spoke-like bonds from a central metal hub to 10 boron atoms equally spaced around a nanoscopic wheel. Alexander Boldyrev and colleagues at Utah State University, Logan, working with Lai-Sheng Wang and colleagues at Brown University in Providence, Rhode Island, point out that to make such highly coordinated molecules in which there are equal distances between the central atom and all peripheral atoms is quite a feat of molecular engineering. It required the chemists to control both electronic and mechanical properties of the molecule. Smaller wheel-like structures based with hexa- and hepta-coordinated carbon and peripheral boron atoms have already been constructed. These molecules fulfilled the electronic and mechanical needs of good bonding. (read more)

New life for old antibiotics

Bacteria can use efflux pumps to rid themselves of antibiotics, becoming drug-resistant until newer antibiotics are developed. By blocking those pumps, researchers can restore the potency of old antibiotics to which bacteria have become resistant. Credit: Sello Lab/Brown University

Chemists at Brown University have synthesized a new compound that makes drug-resistant bacteria susceptible again to antibiotics. The compound — BU-005 — blocks pumps that a bacterium employs to expel an antibacterial agent called chloramphenicol. The team used a new and highly efficient method for the synthesis of BU-005 and other C-capped dipeptides. Results appear in Bioorganic and Medicinal Chemistry. (read more)

In recognition of the 100th anniversary of Marie Curie's Nobel Prize for Chemistry, the United Nations named 2011 the International Year of Chemistry. This fall, the Brown University Library will celebrate IYC with Unveiling the Secrets: the Evolution of Modern Chemistry, an exhibition drawn from the Library's history of science collections. Unveiling the Secrets features a range of printed alchemical texts, as well as key works in early modern experimental chemistry and atomic chemistry. The exhibit opens on Friday, September 30, 2011 and runs through Monday, October 31 in the Gammell Gallery at the John Hay Library.

Behind the purple doors of a sixth-floor Barus and Holley Lab, Thomas Webster, associate professor of engineering, works small but thinks big. His work with nanomaterials, tiny devices implanted into the human body, has led to a potential breakthrough in cancer research.

Webster, director of the University's Nanomedicine Laboratory, has been studying and developing nanotech implants for the past 11 years. His team had created rough implants covered in tiny "nano-features" — microscopic bumps ­— to "mimic the natural roughness of healthy skin," he said. "Current orthopedic implants are flat and smooth, but healthy skin and bone have bumps."

Two years ago, Lijuan Zhang GS approached Webster with a radical idea — exploring how nano-features would interact with cancer cells.

"Being the adventurous person I am, I said, 'Let's try it,'" Webster said. It was completely new territory for Webster, but he said he was excited to see what would happen. Within a year of research, a blink of an eye in lab time, Zhang approached Webster with results they both found fascinating. The addition of 23nm nano-features to a petri dish with both cancerous and healthy cells caused a significantly lower density of cancer cells over time.

Webster said he was pleased and intrigued by the results, but he knew the tests needed to be run at least three more times to verify any findings.

Zhang ran another trial and again found a lower density of cancer cells, but she also found something new — the nano-features inhibited the synthesis of a protein that aids in tumor growth.

The tests had initially been conducted with lung cancer cells, but later tests used breast cancer and bone cancer cells. Both reacted in the same manner — the nano-features lowered the density of cancer cells and decreased the synthesis of the tumor growth protein.

The next step is finding real-world applications, Webster said. "In order for any of this research to be useful, we need a company. We need to transition from the lab bench to a real product."

Webster said he hopes to apply their discovery to animal models and eventually human trials. "If all goes well, a product could appear in five years," he said.

A research team led by Brown University has devised a new technique to spot cancerous tumors in the liver as small as 5 millimeters. The technique, using gold nanoparticles, is the first to deploy metal nanoparticles as agents to enhance X-ray scattering of image tumor-like masses. Results are published in in the American Chemical Society journal Nano Letters.

“What we’re doing is not a screening method,” said Christoph Rose-Petruck, professor of chemistry at Brown University and corresponding author on the paper. “But in a routine exam, with people who have risk factors, such as certain types of hepatitis, we can use this technique to see a tumor that is just a few millimeters in diameter, which, in terms of size, is a factor of 10 smaller.”

The team took gold nanoparticles of 10 and 50 nanometers in diameter and ringed them with a pair of 1-nanometer polyelectrolyte coatings. The coating gave the nanoparticles a charge, which increased the chances that they would be engulfed by the cancerous cells. Once engulfed, the team used X-ray scatter imaging to detect the gold nanoparticles within the malignant cells. In lab tests, the nontoxic gold nanoparticles made up just 0.0006 percent of the cell’s volume, yet the nanoparticles had enough critical mass to be detected by the X-ray scatter imaging device.

“We have shown that even with these small numbers, we can distinguish these [tumor] cells,” Rose-Petruck said.

The next step for the researchers is on the clinical side. Beginning this summer, the group will attach a cancer-targeting antibody to the nanoparticle vehicle to search for liver tumors in mice. The antibody that will be used was developed by Jack Wands, director of the Liver Research Center at Rhode Island Hospital and professor of medical science at the Warren Alpert Medical School of Brown University.

“We have developed a monoclonal antibody that targets a cell surface protein highly expressed on liver cancer cells,” Wands said. “We plan to couple the antibody to the gold nanoparticles in an attempt to detect the growth of early tumors in the liver by X-ray imaging.”

The researchers say the X-ray scatter imaging method could be used to detect nanoparticle assemblies in other organs. “The idea should be that if you can figure out to get that [nanoparticle] to specific sites in the body, you can figure out how to image it,” said Danielle Rand, a second-year graduate student in chemistry and the first author on the paper.

Contributing authors include Yanan Liu from Brown, Wands, Zoltan Derdak and Vivian Ortiz from the Liver Research Center, and Milan Taticek at the Czech Technical University in Prague.

The National Institutes of Health and the U.S. Department of Energy funded the research. Rand’s work was supported by the U.S. Department of Education through the Graduate Assistance in Areas of National Need (GAANN) fellowship, administered by the Institute for Molecular and Nanoscale Innovation at Brown.

A new diagnostic technique can spot tumor-like masses as small as 5 millimeters in the liver. Gold nanoparticles with a polyelectrolyte coating can make smaller tumors more visible through X-ray scatter imaging, enabling earlier diagnosis.

Credit: Rose-Petruck Lab/Brown University

Preferential solvation dynamics in liquids: How geodesic pathways through the potential energy landscape reveal mechanistic details about solute relaxation in liquids J. Chem. Phys. 133, 124503 (2010)

The dynamics of preferential solvation is studied for geodesic paths in a simple atomic liquid mixture. The mechanism for preferential solvation features a reasonably sharp onset for slow diffusion, and this diffusion involves a sequential, rather than concerted, series of solvent exchanges.

The seminal articles are freely available online at: http://jcp.aip.org/editors_choices_2010 until the end of August 2011.

Teresa Ramirez is a first-generation Mexican American and the first person in her family to graduate from college. As a second-year doctoral student at Brown in molecular pharmacology and physiology, she credits inspirational mentors and special science programs with helping her get from the public schools in her disadvantaged community in Compton, California, to the world of university-based research.

On Tuesday, March 23, Ramirez will present her work on cancer research at the second Graduate Students of Color Conference sponsored by Brown’s Samuel M. Nabrit Black Graduate Student Association. This year’s conference celebrating “The Impact of Research, The Promise of Leadership” will be held in Andrews Dining Hall. It is open and free to all Brown students.

“We would like the event to be a moment to reflect not only on the research that the graduate students of color are presenting, but also on its broader impact in our individual academic fields and our communities,” says Chloe Poston, a Ph.D. candidate in organic chemistry and vice president of the Nabrit Association. This year’s event is the second held at Brown – the inaugural conference was in 2008 – and the Nabrit association hopes to make it an annual occasion...

© Nature Chemistry

A unique, dumbbell-shaped twin nanoparticle created by Brown University chemists targets a class of breast cancer cells known as Her-2 tumor cells. Credit: Chenjie Xu, Shouheng Sun/Brown University

Brown University chemists have developed a novel way to treat a class of breast cancer cells. The team has created a twin nanoparticle that specifically targets the Her-2 tumor cell and unloads a cancer-fighting drug directly into it. The result: Greater success at eliminating the cancer while minimizing an anti-cancer drug’s side effects. Findings are published online in the Journal of the American Chemical Society.

Assistant Professor of Chemistry Eunsuk Kim has been honored by the Dreyfus Foundation with a New Faculty Award for promising young scholars. The $50,000 grant will support her research in bioinorganic chemistry aimed at addressing challenging biological and environmental problems.

Kim joined the Brown faculty on July 1 after postdoctoral stints at MIT and Harvard. She received her bachelor’s degree in chemistry from Sangmyung University in Seoul, her M.S. in inorganic chemistry from Korea University, and her Ph.D. from Johns Hopkins University.

Nanobonding

The illustration (left) shows how a RGD peptide-coated iron oxide nanoparticle binds with an integrin-rich tumor cell. At bottom left is a MRI of a mouse with the implanted U87MG tumor (red circle). At bottom right is an optical image that reveals iron oxide nanoparticles (blue) amassed in the tumor area (pink).

Credit: Jin Xie, Brown University Department of Chemistry

On the left is a transmission electron microscopy image of 7 nanometer platinum nanocubes used for oxygen reduction reaction. In the upper right corner of this image is a high resolution picture of a single cube. On the right is an illustration demonstrating the oxygen reduction on a Pt(100) surface of a cube.

Credit: Chao Wang, Brown University Department of Chemistry