Photo by Victor M. Inzunza
Something remarkable happened in Ipsita Banerjee’s lab on the sixth floor of John Mulcahy Hall a couple of years ago. After a year-and-a-half of trial and error, Banerjee, Ph.D., and her undergraduate research assistant, Rose Spear (FCRH ’06), took turns peering through one of the lab’s high-powered microscopes at a group of cells with a mix of relief and disbelief.
What Banerjee, an assistant professor of chemistry at Fordham College at Rose Hill, and Spear had done was take calcium phosphate nanocrystals that they had “fabricated” on biomaterial known as a peptide nanotube and plopped them in the middle of tissue cells. This was the acid test: Would the cells accept or reject the synthetic mineral that is a main ingredient in human bone?
If the cells started to die, it would mean a painful setback. But then, in a literal blink of an eye, success: not only did the cells live, but they started to multiply.
“Rose was in seventh heaven,” Banerjee said. “Needless to say, I was very pleased, as well. It took a long while, but it was worth the wait.”
Worth the wait, indeed, for what Banerjee and Spear had managed to do was show that calcium phosphate nanocrystals, developed from a synthetic process involving nanotubes, could survive in living tissue—and perhaps, one day, in the tissue of human bones.
Banerjee is among a new breed of scientists at the forefront of the exploding field of bionanotechnology. It’s a field that didn’t even exist a few decades ago. Nanotubes are infinitesimally small (you’d have to bind 100,000 of them together to equal the diameter of a human hair) and remarkably powerful carbon atoms that assume a tubular shape.
The ingenious thing is that scientists have learned to not only harvest these frizzy specks, but also manipulate them in any number of ways. Computer chipmakers have begun to pour millions into research and development of nanotubes on the hunch that they are the next big thing at time when the silicon chip has begun to show its age. Silicon Valley’s corporate captains have reason to drool because it turns out that nanotubes, when bound to metals, form crystalline strands that can be up to 100 times stronger than steel and are excellent conductors of electricity.
Nanotube technology is already a nascent industry: A clutch of U.S. startups are now fabricating carbon nanotubes and selling them for about $500 per gram.
Banerjee works in an even newer corner of the field, peptide nanotubes. In simplest terms, a peptide is a molecule made up of two or more amino acids. Get dozens of amino acids chained together by peptide bonds and you have a protein, of which the human body needs an ample supply.
The term nanotube is actually a bit of misnomer. The structures can be grown in a few different shapes, namely circular or ribbon-like. Banerjee said that her work with calcium phosphate involved the tubular variety, but she also frequently uses the circular kind, known as vesicles. For Banerjee, the nanostructure’s ability to form in different shapes is just another example of its versatility. If scientists wanted to fortify a drug with specific nanotubes, for example, they would opt for a circular shape, making it easier for them to be absorbed into the blood stream, not unlike circular red or white blood cells. On the other hand, a scientist developing a “nanobone” might opt for a tubular structure to mimic the actual shape of a femur or humerus.
And better yet, nanotubes are what scientists refer to as self-assembling. Humans, for example, are self-assembling. An embryo is essentially incubated in a womb and then grows and develops on its own into a baby. With the proper manipulation—food, water, education, exercise, etc.—and time you end up with a full-grown adult.
Nanotubes work in much the same way, which is great for science because it mitigates the need for expensive, multimillion-dollar equipment. Prepare the right stew of chemicals, create the right conditions, manipulate the environment just enough and then just let the process run its course.
For all this, nanotube technology is as yet more promise than product—but it’s not for lack of trying. Banerjee maintains a hardy research agenda to move knowledge about nanotubes forward. Together with a small army of undergraduate research assistants, which include Fordham College at Rose Hill students Melanie Dabakis, Robert Tamayev, Marsiyana Henricus, Monica Menzenski, Kristina Fabijanic and Andrew Mastanduono, she is working on the biomedical implications of nanotubes, especially for bone regeneration and as a way to block or reduce the tangles in the brain that are linked to Alzheimer’s disease.
She is also looking into some industrial aspects of nanotubes and nanosensors, examining the role they might play as sentries of sorts, changing color when they come in contact with bacteria, gases or even viruses.
Banerjee is clear, however, that the next phase of her and the field’s research will be the biggest test yet for bionanotechnology: human tissue. Could these synthetic molecules actually play role in regenerating bone, healing muscle or preventing disease? If so, it would be a remarkable breakthrough that could augur a new era in the treatment of everything from osteoporosis to Parkinson’s disease.
“We’re up to mice fibroblasts at this point in our research and in the next few years we’re going to see experimentation with human tissue,” Banerjee said. “We would like to think we have a lot of control [of nanotubes], but I wish we had more. There is a lot we still don’t know. Right now, we are testing all of these things. I know that at a certain pH level [the level of acidity or alkalinity in a solution]I am going to get vesicles and at another pH level I’m going to get tubes, but we always want more control and knowledge.
“That’s why I love research.”
