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Healing the sick with nano-bio hybrids

If their interactions can be controlled, these combinations may lead to new cancer treatments and medical diagnoses

In recent years, researchers have learned how to combine biomolecules such as DNA, RNA and lipids with nanomaterials to develop medical diagnostics and treatments. One hybrid – DNA and carbon nanotubes (CNTs) – may soon be used to treat cancer tumors and deliver drug therapies to cells.

Before that happens, researchers need to learn more about how DNA molecules and CNTs interact with each other. Dmitri Vezenov, assistant professor of chemistry in the College of Arts and Sciences, and Anand Jagota, professor of chemical engineering, work at the cutting edge of this promising area of research.

“The interaction fundamentals are important to understand because we need to know if the CNTs, when they’re used for treatment, will adversely affect the cells they’re binding with,” says Jagota, who directs Lehigh’s bioengineering program.

“Our goal is to provide quantitative data on the interaction strength and composition of these biomolecule-nanomaterial systems.”

Jagota’s CNT experience complements Vezenov’s knowledge of direct single molecule force measurements. The two have received NSF funding to examine the potential of the DNA-CNT hybrid for optical sensing and for delivering biomolecular agents into diseased cells.

Vezenov says DNA-CNT interactions can be difficult to predict. For example, CNTs in a stable solution might be able to carry DNA to a diseased site. “Left alone in this stable state, the hybrid has shown little toxicity,” he says. “But in the cellular environment, we know that it may be affected by other biological molecules. We’re trying to identify, quantify and predict those effects.”

Using atomic force microscopy, the research team, which also includes graduate students Sara Iliafar and Kyle Wagner, watched CNT interact with single DNA molecules. They controlled the chemical conditions in the solution, observed that DNA sticks to a flat graphite surface, and measured the force at which the DNA slowly peels off that surface like a molecular analog of adhesive tape.

The researchers hope to develop models for both the peeling and binding of the DNA-CNT hybrids. These mechanical models combine single-molecule biophysics and continuum mechanics with the goal of addressing some of the health and toxicity concerns with nanomaterials, says Jagota.