“Imagine a world that we could simply ‘print’ neurological diseases out of existence using bio inks and cheap desktop printers.”
Well hello future, or at least one that Matthew Griffith, a biophysicist at the University of South Australia, is willing to entertain.
He heads up a cross-institutional project team working to take the basic premise of implantable medical devices a step further – to customisable patient-specific medical implants.
These implants are made from flexible plastics with bioactive substances printed upon them to provide functioning replacements for parts of the body’s signalling systems that don’t work.
Metals and silicon are, he points out, hard and stiff, and while science fiction might like to imagine implanted cyborgs as masses of flesh and metal, it’s not particularly conducive, in reality, to making functional parts at the micro and nanoscale. His research is focused on closing the gap between the biological and electronic worlds.
“We’re basically making soft and flexible plastic materials, which can conduct electricity to talk to the neural networks,” Griffith says.
“Because our bodies are also made of soft and flexible carbon, essentially, these materials then don’t get rejected by the body like traditional electronic materials.”
The proprietary technology Griffith’s team is developing is ‘bio invisible’, as if the body doesn’t know it’s there. But if successful, it could plug gaps in sending electrical signals where they need to go. He believes this technology could consign a range of diseases and disorders related to the brain to history’s dustbin, though that is still decades away.
Eyes on the prize
I ask Griffith to take one of his targets: the eye.
High school science studies learn of the role of the rods and cones – intricate photoreceptors in the retina that receive light and act as the information conduit to the brain. In some people, these cells don’t quite work as they should, leading to diseases like retinitis pigmentosa or disorders like macular degeneration.
The technology Griffith’s group is developing is intended to replace those malfunctioning photoreceptors. It will use conductive polymers – electricity-conducting plastics – constructed from conjugated carbon molecules, with printed bioinks in the formation of a patient’s photoreceptors upon it.
“You can put down little dots which are designed to replicate the dot of a single rod, or a single cone,” Griffith says.
The challenge is configuring these rods and cones to match what is naturally occurring in a patient’s eye – “you can’t just manufacture a single template and essentially stick it into a number of different patient’s eyes because it won’t spatially line up in every single patient” – so instead super high-resolution microscopes are used to image the back of a person’s eye to grab the retinal template.
It’s then used to dot print on demand onto the conductive surface.
The same principle applies to platforms to treat other disorders. Neurological diseases like Parkinson’s could be improved using bioinks printed on precision-designed plastic to chemically “talk” to neurons.
“We know inside the body that neurons actually use this combination of electricity, chemical signals and mechanical signals of spatial arrangement in their native functioning,” Griffith says.
It means turning the sledgehammer of existing treatments that use electrodes to channel electricity into the brain into a “little, gentle, velvet glove” that gives neurons what Griffith calls an “electric tickle”.
Model first, human later
Griffith’s work is nascent, it hasn’t been implanted into a living creature yet. And while the promise of curing the incurable is enticing, fully realising this technology for the public is likely decades away.
The first step will be trials in animal models: pigs, likely, for blindness, given their retinal structure is similar to that of humans. For neurological disorders, mice and rats tend to be the preferred model. Once the technology reaches a point of testability and an ethical clearance is given, the work in other mammals can begin.
Despite the long road ahead, patents can be acquired to protect the technological IP and progress with confidence. Implants are having a moment as well, albeit controversially, with Elon Musk’s Neuralink making headlines for its first human trials last year.
“We’re talking to patients and clinicians firstly about what is the burden we need to overcome to prove this technology from a med tech product point of view,” Griffith says, “and then what would an animal trial look like? The next stage for us would be to essentially prove safety – which of course, is very important – and also efficacy, that the devices work inside an animal model.
“And then after that, the traditional medtech pitch for investors and providing the value proposition as you try and enter human clinical trials, which would be still some years away.
“The focus of the Future Industries Institute where I work here at UniSA is that we’re working at the coalface of technologies that we believe are going to have a big impact on society. In this case, just a restoration of, at this stage hope, but hopefully [also] choice in people’s lives.
“If the neurons don’t work properly, that particular disease is currently incurable. Just coming up with even rudimentary solutions to neurological conditions – it’s going to provide hope to billions of people throughout the world.”
