6 December 2017
Time: 3:00 - 4:00pm
Venue: David Sizer Lecture Theatre, Bancroft Building, Mile End Campus
Professor Nick Donaldson, UCL, will be the next speaker in the Institute of Bioengineering Seminar Series with “Using integrated circuits for neural interfaces: is this realistic for chronic implants?”
Prof. Donaldson writes: "As feature sizes of ICs get smaller year by year, the possibility of arranging one electrode per neuron rises: this is surely the ultimate for neural interfaces. Each electrode may need an associated amplifier, stimulator or multiplexing switches, and these may be adjacent to the electrode. We can therefore imagine using pads as electrodes and protecting the remainder of the surface with some suitable coating. But how long would such a device survive in the body? As a neuroprosthesis, it is likely that it should be required for a long time, perhaps for the rest of the patient’s lifetime, and that is
a very demanding requirement: we would like to know whether it Is possible.
We have started accelerated-aging experiments on protective coatings, initially with combinations of thin-film passivation layer and thicker (~10 micron) silicone encapsulation. These experiments use Electrical Impedance Spectroscopy, now quite a well-known method, but with many samples (~240). This is quite a challenge given the impedance levels are up to 1TΩ.
In this seminar, I will describe some implants that require minimal encapsulation, also the apparatus that we have developed and the results of experiments so far. We are planning to increase the range of parameters under investigation: the acceleration due to temperature, the driving voltage, the materials and the imitation body fluid, so that we can predict lifetimes from usage and design."