by Sharon J. Proctor
Photograpy by Greg Ehlers

Turning molecules on and off
When SFU’s Neil Branda was a child, he liked to “tinker” with things. “I liked building models and inventing things, and I liked cooking. With cooking I could dabble and explore.” Now, decades later, he’s still tinkering and dabbling. Only now his focus is organic molecules – but not just any organic molecules. He targets only the ones whose special properties can be turned on and off at will, using light or electricity. They’re called “molecular switches.”

Professor of chemistry and holder of the Canada Research Chair in Materials Science, Branda came to SFU in 2001 after a faculty stint at the University of Alberta. In 2006 he was named one of Canada’s “Top 40 Under 40,” an honour given to those who are especially successful before they reach 40. The award isn’t surprising considering that since his arrival here his molecular switching research has already produced three patents, spawned a new B.C. company, and resulted in more than 25 scientific papers. He’s also the founder of the Nanomed Canada Research Network, a community of researchers who are developing disease-fighting devices and materials the size of individual molecules. You’ll find Branda’s office deep inside a multi-storey maze of hallways and laboratories that make up the new $40 million research centre, 4D LABS, located in the new Technology and Science Complex (TASC2) on SFU’s main campus.

Neil Branda was born in Montevideo, Uruguay, and raised in Hamilton, Ontario. Although his parents were both professors in McMaster University’s biochemistry department, young Neil wasn’t particularly studious. “In high school I liked cooking and sports. I was good enough, but I wouldn’t say I was an excellent student or a bad student. And at the University of Toronto I wasn’t on a particular path. I took biology, chemistry, physics, and humanities. In fact, one of my main interests was classical mythology and civilizations.” So he took an Ancient Greek history course in his second year. “The professor, after reading my final essay, turned to me without blinking, and with a poker face suggested I stay in the sciences. So I dropped my humanities courses. I went into chemistry because it was easy for me, the path of least resistance.” He went on to get his PhD at MIT. “Some people don’t like to hear this, but I often tell students to pursue what they’re good at, not what they like.”

Can you believe it? He hated math!
“I was terrible at it. That’s why I became an organic chemist, because you don’t need a lot of math. I’m a visual person, not a logical person. If I can’t ‘see’ it in my mind, I can’t do it.” He finds organic molecules easy to visualize. “Apparently identical organic molecules have different properties based on how they’re shaped or folded. Take the molecule that gives caraway seeds their odour and flavour. It’s called ‘carvone’ and it’s the same substance that gives spearmint its odour and flavour. They’re mirror images of each other. This area of chemistry is purely visual. When I see a representation of a molecule on a piece of paper, I can see it instantly in my mind, in three dimensions.”

In his research, “shape” is everything. As he explains, “The shape of a molecule is based on the architectural arrangement of the building blocks (atoms) that form it and how they’re connected to each other. Its shape is what gives a molecule a particular property, such as a specific colour or taste, or the ability to glow in the dark or to act as a drug.” His molecular switches involve synthetic organic molecules that are built and shaped according to what people want them to do. “Chemists for years have been precisely controlling the structure of molecules. They’ve been building molecules with a precise arrangement of atoms to give them specific properties or functions.” Branda’s group develops molecular “switches” that turn those properties on and off. And often their switch mechanism is inside the targeted molecule.

Molecular switches are not unique to the laboratory. They exist in nature, too. One such switch is rhodopsin, a red pigment located in the retina of our eyes, in the rods used for night vision. When light hits rhodopsin, it bleaches and divides in two, and this switches on a chemical sequence that leads to vision. When it’s dark once more, the pieces re-form rhodopsin.

Branda’s switches are turned on and off using light or electricity. For example, one molecule he and his students developed is colourless, but becomes deeply coloured when sunlight hits it. Yes, eyeglasses do this, but this molecule can be changed back to colourless instantly, using electricity. Were it in your home or car windows, you’d have lower heating, cooling, and lighting bills.

Branda, in fact, set up a company called SWITCH Materials Inc. to develop a “smart windows” technology. “It has the potential to improve people’s lives,” he says.

The SFU group has also been working with antibiotics called “enediynes,” which attack the DNA of tumour and bacterial cells. Enediynes occur naturally in certain soil bacteria, which release them into the surrounding soil to keep out other bacteria. Enediynes are highly toxic (the soil bacteria have a protective mechanism), so before they can be used to treat disease, they must enter the body in a safe, non-toxic state and become toxic only on command. Branda’s team has found a solution. Using ultraviolet light, they can convert toxic enediyne molecules into a stable non-toxic architecture. The molecules become toxic again only when exposed to visible light!

When he’s not in his laboratory or office, or speaking at conferences, Branda likes to be outside snowboarding or wakeboarding. “And,” he adds, “I still like to cook.” aq

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