Worldwide people love to watch movies. A good film can be both transporting and intimate, helping you to understand the intricate motivations of other people or revealing aspects of life you previously overlooked. Now, researchers at Oregon State University and the University of Alberta have developed a new imaging technology with shutter speeds so fast, scientists can make "molecular movies" and observe life processes as they happen.

Using this powerful new technology based on green fluorescent proteins, scientists also will be empowered to develop improved biosensors — internal CCTV cameras, so to speak — capable of recording everything from nerve impulses to cancer metastasis. "With this technology we're going to be able to slow down the observation of living processes and understand the exact sequences of biochemical reactions," said Dr. Chong Fang, assistant professor of chemistry at OSU and lead author of the published research.

How It Works

"Green fluorescent proteins," which are found in a type of jellyfish living in the cold waters of the north Pacific, have become extremely popular in bioimaging and biomedicine. The jellyfish contains a bioluminescent protein, known as aequorin, that emits its own blue-green rays whenever light shines upon them. Originally discovered in 1962, scientists soon developed various applications for the proteins and they eventually became the basis for a Nobel Prize awarded in 2008. The new molecular movie-making technology developed by Fang and his colleagues builds upon these green fluorescent proteins, while also using advanced pulse laser technology that is, in itself, fairly new.

"For decades, to create the sensors we have now, people have been largely shooting in the dark," Fang said in a press release. "This is a fundamental breakthrough in how to create biosensors for medical research from the bottom up. It's like daylight has finally come." Using short pulse lasers and the bioluminescent proteins, the new imaging technology's shutter speed is so fast it must be measured in femtoseconds. How speedy is this? Well, a femtosecond compared to one second is equivalent to one second compared to roughly 32 million years.

"We now have a camera fast enough to capture the molecular dance of life,” Fang said. “We're making molecular movies.” Significantly, the new technology is able to record the proton transfer associated with the movement of calcium ions, which is one of the most basic aspects of almost all living systems — and also one of the fastest. Once scientists identify what is happening, one step at a time, with proton transfers, they will be able to build on that knowledge to create customized biosensors for other life processes. This should improve the study of everything, said Fang, from cell metabolism to nerve impulses, from how a flu virus infects a person to how a malignant tumor spreads.

 

Source: Oscar BG, Liu W, Zhao Y, et al. Excited state structural dynamics of a dual-emission calmodulin-green fluorescent protein sensor for calcium ion imaging. Proc. Natl. Acad. Sci. 2014.