Nature is very good at building complex things. Plants and animals grow from tiny single cells containing all the information needed to build the organism encoded in DNA. In contrast, humans need vast factories and machines to build anything near as complex. But to build like nature requires knowledge of biological processes which aren’t fully understood. My research work is split between investigating basic biological processes and using what has been learned to try to build things.
Interrogating biology: I investigate biology using advanced optical microscopes, capable of observing individual molecules at work inside living cells. These microscopes exploit fluorescence where certain molecules called fluorophores emit longer wavelength light when excited by a shorter wavelength. By filtering out the excitation light and only observing light emitted by fluorophores, a very high signal to noise ratio is achieved. Using very sensitive high speed cameras and high intensity lasers, single molecules of fluorophore can be observed. Most biological processes in cells are driven by proteins, so to observe them, they must be replaced with fluorescent copies. This is done directly at the genetic level, replacing the gene for a protein of interest with a functional fluorescent copy. I’ve used this technique to observe lots different biological processes including DNA replication, cell division and photosynthesis.
Learning to build like nature: The cells in our body are made sturdy through a structure called the cytoskeleton, which is as it sounds, a molecular skeleton inside each cell. It expands out from the nucleus to the edges of the cell in a dense network. But the cytoskeleton has another role, it also serves as a kind of railway, allowing other protein transporters called motor proteins to transport cargo around the cell. Inspired by this, I tried to employ the same design ideas to build my own nanoscale railway. I extracted motor proteins from cells, as well as the cytoskeleton tracks, called microtubules. To control everything, I borrowed another component from the cell, DNA, using the information carrying capabilities of DNA to instruct the motor proteins. Some of them became assemblers, putting the tracks together into a star shaped network called an aster. Others became shuttles, carrying cargo or other DNA signals into the centre of the aster. The nano-railway could be used to gather components to speed up chemical reactions or help detect very dilute analytes in a biosensor.