When you can’t repurpose something and can’t have it made to order, the only option is to make it yourself. Romeo Racz and Mihaly Kollo, along with their group leader Andreas Schaefer and their wider team, study brain signals – specifically how mice respond to smells – and needed an extremely precise way to monitor brain activity.
The team have developed incredibly thin microwires called jULIEs™. Five of them bundled together are not quite as thick as a human hair. The wires are advanced enough to be used to track signals around the brain but so thin that they can even bend around capillaries when they’re inserted.
The project depended on bringing together a huge range of scientific knowledge. “We had to become experts in so many fields – neuroscience, polymers, glasses, metallurgy. Basically, every single person is outside their comfort zone in some way. The more interdisciplinary the team is, the higher the chance you have of making it work,” says Mihaly.
Now that they have a process for quickly and reliably producing the jULIEs™, with help from the Making Lab STP, it’s relatively easy to change the coatings on the wires’ tips to use them as different kinds of sensors.
By coating the tips in iridium oxide, for example, the wires become very sensitive to oxygen and can be used as pH sensors. Different tissues and even different kinds of tumours have different pHs, so the wires could be used as a minimally invasive way to map tumour locations inside the body.
Along with Crick cancer researchers and with support from the Crick’s Translation team, the team is currently working with doctors at University College Hospital to investigate even more potential clinical uses for the wires.
Making your mark
A familiar face branded onto a single grain of pollen using Lizzy and Yuxin’s microscope.
Down in one of the Crick’s basement floors is the Electron Microscopy Science Technology Platform. There, senior laboratory research scientist Lizzy Brama and undergraduate sandwich student Yuxin Zhang have built a microscope which could save a huge amount of time and work for researchers using a scanning electron microscope.
Scanning electron microscopy fires a narrow beam of electrons at a sample and gradually builds up a picture of the surface by measuring the signals which are reflected back. By scanning extremely thin slices of a sample, you can build up a 3D picture of the structures inside it.
But this long and sensitive process produces enormous amounts of data. If you’re trying to image one neuron in a sample of brain tissue but can’t see it in detail before you direct the microscope towards it, how do you make sure that you’re not creating ten times – or one hundred times – the data you need?
“The real secret to working with big data is to not make big data,” says Martin Jones, who leads the microscopy prototyping activities in the STP. Lizzy and Yuxin’s set-up helps to do just that.
Lizzy and Yuxin have built a light microscope which can be used to image a sample before it’s moved to the electron microscope. It uses a beam of infrared light to produce thorough but relatively low resolution images.
But this same infrared beam can also be used to burn very small and precise patterns into samples. When the sample is then transferred to an electron microscope, the branded marks are still visible.
Lizzy explained that the branding system is flexible enough that researchers could even draw a minuscule arrow or write notes directly onto a sample for future reference. “There really isn’t any limit on what you could draw with it.”