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8 Headlines Ten years on: the pill-sized pressure sensor for the brain Ten years ago, Professor Simon Malpas, a bioengineer from the University of Auckland, had the idea of making an implantable sensor to measure pressure in the head. He successfully applied to the Neurological Foundation for a grant to get the research off the ground, receiving an initial two-years' funding worth just over $150k. Today, the team at the Implantable Devices Group at the Auckland Bioengineering Institute (ABI) has developed a prototype and are now completing the final, complex steps required for clinical trials to begin. Reaching this stage has meant mastering a range of technical innovations. “This is not an academic exercise; we want to make sure this is manufacturable and get it to market. We won’t be satisfied until we can get it into clinics and used in the real world,” says Professor Malpas. The device is a super sensitive medical pressure sensor, slightly smaller than a Panadol tablet, which would be implanted into the brain of patients with hydrocephalus. Hydrocephalus is an increase in fluid inside the brain which, unless treated, may be fatal. About 100 New Zealanders are diagnosed with hydrocephalus each year. At present hydrocephalus is treated with a thin shunt surgically implanted in the brain, which, for a range of reasons, blocks in half of cases within two years. The device would be implanted at the same time as the shunt and would give an early warning of a likely blockage, preventing unnecessary hospitalisations. Both neurosurgeons and parents of children with hydrocephalus have said this would be a “game-changer”. “Imagine being a parent and told your baby has an abnormal build-up of fluid on their brain. You’re grateful that there is a treatment, but then you’re told that the tube inserted into your child’s brain is quite likely to block.” “It would alleviate the considerable anxiety and suffering of parents of children with the disorder, as well as highlight the potential of remote monitoring of chronic conditions wherever a patient lives and ultimately, the means of providing more equitable healthcare,” says Professor Malpas. If successful, it would be the first New Zealand-designed fully implanted electronic medical device, akin to the complexity of a cochlear implant or pacemaker. The project has taken the research team through largely uncharted territory. Each of the elements that go into the implantable device required coming up with a range of innovations. The first stages involved identifying what material it would be made of. It would need to keep patients and the device safe from, for example, an attack by the immune system. “We had to ask ourselves, ‘would we allow our sensor to be put into our own child?’. ” They turned to glass, which has many virtues. It is biocompatible – a material that is accepted by the human body. Modern microfabrication techniques have enabled a new generation of medical implants that are made from glass instead of polymers. “We are using the microfabrication techniques developed for silicon chips and using those for glass,” explains Bryon Wright, senior sensor development engineer at the ABI. “And we’ve teamed up with world-leading glass manufacturing companies to enable fabrication of glass sensors, ensuring high quality and low costs through scalable production.” Another key challenge has been finding a way to ‘power’ the miniature device without wires. To achieve this, the team has incorporated inductive power transfer technology, which has been developed at the University of Auckland over the past 20 years. The tiny devices with ENORMOUSPOTENTIAL (continues)