A vampire’s vital molecules
By using an old-fashioned mortar and pestle to make a molecule called porphyrin, Dr. Tamara Hamilton is hoping to help chemists ‘green’ their labs
By Jim W. Harper
Assistant professor of inorganic chemistry, Dr. Tamara Hamilton (right) and student research assistant Andrea Orvieto use an old-fashioned mortar and pestle to make a group of chemical compounds known as porphyrins. Using fewer raw materials to produce porphyrins saves money as well as natural resources, helping chemists to green their labs.
Ever wonder why a vampire can’t stand garlic? Garlic is full of sulfur, and that element is an anathema to someone suffering from a rare disorder of the blood, called porphyria. The disease’s symptoms have been conjectured to be the origin of the vampire myth because of their similarities: vampires “vant your blood” because their hemoglobin has something wrong with it, and that something involves a vital molecule called a porphyrin. This molecule is the obsession of one of the newest researchers at Barry University.
Dr. Tamara Hamilton does not worry about vampire bats or witchcraft when peering into the microscope. She is looking for evidence of a perfectly-formed, pocket-shaped molecule. Porphyrins, pronounced POUR-fur-ins, may sound like a spa treatment for exotic pets, but they are actually hollow nano-bricks within cells. They can combine with other building materials to produce an iron smelter for your bloodstream or a photosynthesis lab for plants. Besides helping hemoglobin to carry iron and plants to absorb the sun, porphyrins help the body to absorb Vitamin B12.
While difficult to produce in the laboratory, these organic molecules exist everywhere you look in nature. Porphyrins put the “green” in chlorophyll, and that characteristic reverberates in Hamilton’s work, because she is experimenting with environmentally friendly, green methods to produce them. If successful, her research will demonstrate for the first time that these building blocks can be produced commercially without leaving behind large amounts of toxic waste.
Her technique could be used in laboratories around the world that are developing the latest pharmaceuticals. “We are working on making it reproducible and scaling it up, so that the process could be applied in industries,” Hamilton explains.
An assistant professor of inorganic chemistry, Hamilton came to Barry in August 2008 after completing post-doctoral work in chemistry at the University of Montreal. “Everyone here is really supportive. Four professors share space in the same laboratory, and that wouldn’t work out well in every university. Some researchers can be very proprietary with their equipment,” she noted.
Assisting with her line of inquiry are three student researchers. Two of them, senior Cherice Boyce and junior Frantzesca Belancourt, synthesize porphyrins using a traditional method, which requires a liter of harsh, propionic acid to produce only one gram of solid porphyrins in a purplish, powder form. That same gram of powder can be created by adding much smaller amounts of base ingredients into a simple mortar and pestle and applying a little elbow grease.
So another student assistant, senior Andrea Orvieto, gets a real workout in the laboratory. She combines the two liquid reagents in the mortar and grinds them with the pestle until a solid is formed.
“We were both really excited to see what happened with the mortar and pestle,” says Orvieto, chemistry major from North Miami Beach who is on schedule to graduate in December 2009. “As I’m the first student to work with her, I can really call this my project, because I started it from scratch.”
Orvieto has taken the entire chemistry program to heart, and she has benefited from Barry’s RISE (Research Initiative for Scientific Enhancement) program for students pursuing the sciences at minority-serving institutions. She had planned to become a veterinarian, but her chemistry professors at Barry inspired her to continue her studies to the Ph.D. level.
“It’s been wonderful. I came into research not knowing anything about porphyrins, and [Dr. Hamilton] really explained things very thoroughly. She is very patient and a wonderful lady in general,” Orvieto says.
By comparing the novel, low-tech method with the traditional method, Hamilton will be able to determine if this “greener” method is as effective as the more wasteful, toxic method. “I’m a making-porphyrins-in-the-solid-state specialist,” she quipped. “But if our method is too hard to purify, then it’s no good.”
The solid-state porphyrins must be pure enough for use in highly precise laboratory work, and that requirement is why industries currently opt for the more wasteful method of producing them. The method using less acid has two fundamental problems with purity and stability, which Dr. Hamilton explains this way:
“First, if the reaction mixture is not homogeneous, the wrong products may form. Secondly, entropy [the tendency of all systems toward disorder] can take over and give us a whole lot of different products, most of which we don't want. That's why, traditionally, solvents are used to facilitate chemical reactions, as they allow the more thermodynamically-stable product to be formed. For some reactions however, chemists are finding that a solvent-free method works just fine. This is the first time it has been used to make porphyrins.”
A secondary goal of Hamilton’s research is to use the porphyrins as bricks to create specialized 3-D molecular cubes or polyhedra. These flat-sided structures, like boxcars of a train, could function as the transportation system for new, life-saving drugs.
“Porphyrins are big, flat molecules, which makes them ideal for the faces of a cube,” says Hamilton, a native of Nova Scotia with a Ph.D. in chemistry from the University of Iowa.
While she admits the South Florida heat was a shock to her system when she arrived last summer, Hamilton says she has no problem with the plentiful sunlight in the winter. But a vampire with porphyria certainly would. Dysfunctional porphyrins can clog the bloodstream and “make us pale and require blood transfusions,” she says. The condition also makes the victim very sensitive to the sun – hence the connection of porphyria to the vampire legend of being pale, blood-thirsty and afraid of the sun.
Although she is awaiting further results before publishing her experimental findings, Hamilton is already shedding light on wasteful practices in the laboratory. Using fewer raw materials to produce porphyrins saves money as well as natural resources, making this method desirable for cost- and environment-conscious industries. The Environmental Protection Agency has even issued green chemistry guidelines, and chemists like Hamilton are investigating ways to reduce the imprint of their work. Just as architects are learning to construct green buildings, chemists are learning how to conduct greener chemistry in their laboratories.
Although her research may involve a little old-fashioned elbow grease Hamilton says it is worth the effort. By attempting new means of green chemistry, her students are learning to think and act more responsibly in the laboratory. And, perhaps, they are creating a little magic in the purple powder of porphyrins. Who knows what they might be used to cure next?