The microscopic processes involved in human fertilisation are a difficult thing to convey visually, but a group of scientists, using Star Wars as their inspiration, have managed to do just that, creating a highly entertaining and informative video — while accidentally stumbling upon a new scientific discovery in the process.
The three-minute video called "The Beginning" was put together by Don Ingber, the founding director of the Wyss Institute for Biologically Inspired Engineering, and Charles Reilly, a staff scientist at the Wyss Institute who previously worked with film director Peter Jackson at Park Road Post film studio.
"I feel that there's a huge disconnect between science and the public because it's depicted as rote memorisation in schools, when by definition, if you can memorise it, it's not science," Ingber explained in a statement. "Science is the pursuit of the unknown. We have a responsibility to reach out to the public and convey that excitement of exploration and discovery, and fortunately, the film industry is already great at doing that."
Image: Wyss Institute at Harvard University
So by intertwining science with art, Ingber and Reilly were able to look at nature, and even pre-existing hypotheses about molecular processes, through a completely different lens. The video and the new findings were subsequently published in the science journal ACS Nano.
For the short film, Ingber and Reilly chose the space-based aesthetic of Star Wars, substituting sperm for rebel X-Wings and an egg for the Death Star. So it's more like "Sperm Wars" than Star Wars, where millions of sperm swim and compete to be the first to fertilise the egg.
The key was to keep it entertaining and scientifically accurate. The intricate movements of the sperm's tail required the construction of a multi-scale biological model that went from the level of cells down to individual atoms. It's like starting at the level of the Empire State Building and zooming in close enough to see the individual nuts and bolts that holds the structure together.
"It turns out that creating an accurate biological model and creating a believable computer-generated depiction of life in film are very similar, in that you're constantly troubleshooting and modifying your virtual object until it fits the way things actually look and move," Reilly said. "However, for biology, the simulations also have to align with recorded scientific data and theoretical models that have previously been experimentally validated."
To create the video, the researchers combined physics-based film animation software with molecular dynamics simulation software, while having to ensure that the movements were accurate across all size scales.
Rows of dynein proteins along the microtubules of an axoneme moving in sync to cause the axoneme's motion. (Image: Wyss Institute at Harvard University)
A key achievement of the video was the portrayal of the sperm's axoneme — a long tube consisting of nine pairs of microtubules arranged in a column around a central pair, and which extends along the entire length of the tail. The video shows how the axoneme bends and stretches, providing the source of the tail's locomotive abilities. Diving down even further, this engine consists of motor proteins known as dyneins. Rows of dynein proteins within the axoneme move in sync, producing motion — a process akin to rowers all pulling at the same time in a boat.
It's here that the researchers discovered a new molecular process. While creating the three-dimensional, dynamic functional model of the molecular motor, the researchers learned that a specific hinge region of a dynein molecule will spontaneously move in its characteristic direction when force is applied at the binding site, that is, at the point where a chemical bond is broken and energy is released. That's something scientists hadn't seen before.
This video is a potent reminder that biological systems are highly mechanistic, all the way down to the atomic scale. It's not a coincidence that the video was published at nanotechnology journal ACS Nano; eventually, scientists will be able to manipulate — and even construct — machines at this scale. In the meantime, we can watch this stunning new video and marvel at what nature has been able to create on its own.