Public Release: 

Ph.D. Degree Research Results In Patent For Low-Cost Pharmaceutical Filters Made From Seafood Waste

Virginia Tech

(Blacksburg, Va., May 24, 1999) Jason Todd of Newport News, Va., earned a patent for his Ph.D. degree research even before receiving his degree in wood science from Virginia Tech.

Todd's dissertation research has resulted in a new, low-cost material for purifying proteins, such as to capture antibodies from blood serum or cell cultures. Such antibodies are used in diagnosis and treatment of diseases, as well as testing for drug abuse.

Todd, along with Wolfgang Glasser, professor of wood science in the College of Natural Resources, and Swapan Roy of LigoChem Inc., who received a patent (No. 5,770,712, June 23, 1998) for "Crosslinked hydrogel beads from chitosan," were recognized for their work by Virginia Tech Intellectual Properties, Inc. last week.

Chitosan is a modified form of chitin, a structural component in crab and shrimp shells. "So chitosan can be isolated from seafood waste," Todd explains. The material is formed into hydrogel beads, which are mostly water or "a highly swollen polymer network" and used in pharmaceutical separation processes. The beads are coated with "chemical functional groups" or "ligands" that grab or attract the target proteins such as antibodies or antigens.

Chitosan beads are not new. Neither is the process of using beads in separation. "The ligand is a group of atoms that interacts with the target molecule, resulting in attraction. A positively-charged ligand will attract a negatively-charged protein, for example, since opposite charges attract. Other types of interactions, such as hydrophobic interactions, can be used as well.," says Todd.

"The basis of the patent is the way we attach the ligand to the beads," he says. "We use a spacer arm to separate the ligand from the chitosan molecule. Having the space between the ligand and the supporting chitosan chain results in better selectivity -- better control in terms of getting the proteins you want to stick to your molecular structure without getting the ones you don't want. The flexible spacer gives the ligand more space in which to interact with the protein."

So far, Virginia Tech Intellectual Properties, Inc. has licensed the technology to LigoChem, a start-up company in Fairfield, N.J. "LigoChem has selected an affinity ligand that allows them to purify antibodies as well or better than present technology at lower cost," says Todd.

Why was a wood science and forest products major doing research with seafood waste? NOT because of growing up in York County near the Chesapeake Bay and being aware of the abundance of seafood byproducts, Todd admits.

"In high school I did well in chemistry, science, and math. The job prospects in engineering looked good, so I went into chemical engineering. But, when I was a senior, my friend Jim Sealey, a graduate student working with Dr. Glasser, told me he was doing interesting work with biomass.

"Much of Dr. Glasser's research is similar to what someone in materials science, chemical engineering, or chemistry might be doing," Todd says. "The only difference is that his students work exclusively with naturally-occurring materials. My work in wood science is a natural progression from my undergraduate education in chemical engineering."

Todd says he thought a career in research would be more fulfilling than the jobs available to chemical engineering bachelor-level graduates, "So I decided to go to graduate school to learn how to be a researcher. It was really Dr. Glasser's personality that attracted me into his research group."

Glasser was working with cellulose. So Todd did his masters on reactions of cellulose in solution. "We learned of some limitations of cellulose gel beads that we hypothesized could be avoided by working with chitin, a close cousin of cellulose," says Glasser. "What cellulose is to trees chitin is to marine organisms; they are chemically very similar."

"Cellulose solutions can be used to make beads," Todd explains. However, "cellulose does not dissolve in ordinary solvents. The solvent used was toxic, corrosive, and expensive mixture."

Other graduate students in Glasser's group were investigating chitosan. "It also can be solidified from solution droplets to make spherical beads, with the major attraction that it can be dissolved in mixtures of water and acetic acid -- essentially strong vinegar," says Todd. "It's a much more user-friendly solvent." Chitosan also has other properties that give chitosan beads certain advantages over cellulose beads, including greater ease of attachment of ligands.

Todd was looking for a project for his Ph.D. "The chitosan bead project seemed interesting, since it would allow me to combine elements of chemistry, chemical engineering, and materials science in my research," he says. "Plus there was funding available for the project -- an important consideration."

When he's not doing research, Todd likes mountain biking. "That's the forestry connection," he says. "I'm occasionally at one with the trees." He is also interested in music. He played the saxophone in the Tabb High School band and took up with local rock bands when he started college, playing bass guitar. Most recently, he played with the still active Blacksburg area rock band "Visible Shivers" -- but quit to finish his dissertation. "It was hard to justify travelling out of town and staying up all night."

When he gets his Ph.D. this summer, Todd hopes to continue his research in the polymer science field or in forest products.

Glasser, who has produced and patented a number of cellulose-based separation materials in the past decade, including with other graduate students, is continuing to develop and patent chitosan-based materials and products.

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PR CONTACT: Susan Trulove, 540-231-5646, STrulove@vt.edu

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