Carbon Biomaterials at the Interface between Electronics and the Human Nervous System
Dr David J. Garrett
The University of Melbourne, School of Physics
Time & Place
Thu, 17 Nov 2016 11:00:00 NZDT in Rutherford 531, Level 5
All are welcome
With the incredible success of cochlear implants for the deaf and rapid advances in retinal implants for the blind, bionics is no longer the stuff of science fiction. For now the majority of applications are in medicine but it is easy to forecast that efforts to integrate electronics with our biology for the purpose of enhancing our physical abilities, for heightening our senses or purely for entertainment, will not be far behind. In either case, a critical challenge is the creation of interfaces for transfer of information to and from the peripheral or central nervous system. Active neurons produce electrical signals that can be recorded and neurons can be activated by introducing small packets of electrical charge into their immediate vicinity. External recording systems such as MRI or EEG are safe and non-invasive but are cumbersome, record with low resolution and cannot activate or stimulate neurons. Stimulation with light requires that neurons be genetically modified to produce light sensitive proteins and thus the technology has a long way to go before being safe for human use. The “go to” technology for high resolution interfaces therefore is implantable electrode arrays. Our immune systems however are highly evolved to protect us from foreign materials inside us and employ a variety of strategies to either destroy or neutralise the threat. If implantable electrodes are going to be a viable technology for the future of neuromodulation implants they need to be at least invisible to the immune system but ideally they will work with the immune system to actively generate high fidelity long lasting connections. This talk will introduce some of the research we have conducted (Figure 1) and techniques we have developed pertaining to fabrication of devices from all carbon materials; diamond, graphene, carbon fibre and carbon nanotubes. For the Bionic Vision Australia high acuity retinal prosthesis for instance we used diamond both as an encapsulant for electronic components and as a retinal stimulation interface. More recently we have produced flexible electrodes from graphene and carbon nanotube yarns that show promise as a dual recording and stimulation electrodes. Our hope is that the low bio-reactivity of carbon materials and the ease with which carbon materials can be surface modified will enable engineered suppression of the immune response and hence long lasting, high fidelity neural interfaces.