University Researchers Develop Vision Implants

Researchers from Chalmers University of Technology in Sweden, the University of Freiburg, and the Netherlands Institute for Neuroscience have created a small implant that can change future vision implants for the blind. 
 
The developed implants are exceptionally small, containing electrodes as small as a single neuron, and can remain intact in the body over time. Researchers believe that electrical impulses sent via an implant to the visual cortex of the brain can create an image, and each electrode would represent one pixel.
 
Maria Asplund, who led the technology development part of the project and is Professor of Bioelectronics at Chalmers University of Technology in Sweden said: “This image would not be the world as someone with full vision would be able to see it. The image created by electrical impulses would be like the matrix board on a highway, a dark space and some spots that would light up depending on the information you are given. The more electrodes that ‘feed’ into it, the better the image would be.”
 
By creating a miniature electrode, the size of a single neuron, researchers have the potential to fit lots of electrodes onto a single implant and build up a more detailed image for users. A mix of flexible, non-corrosive materials can make this a long-term solution for vision implants.  
 
Researchers describe the vision implant created in this study as a ‘thread’ with many electrodes placed in a row. In the long term, several threads would be needed with thousands of electrodes connected to each one; the results of this study are a step toward that type of implant.
 
The electrical implant that Asplund and her team created was 40 micrometers wide and 10 micrometers thick. Asplund’s team also created a unique mix of materials to prevent corrosion, including a conducting polymer to transduce the electrical stimulation required for the implant to work. Acting as a protective layer, the polymer makes the electrode much more resilient to corrosion.
 
“Miniaturisation of vision implant components is essential. Especially the electrodes, as they need to be small enough to be able to resolve stimulation to large numbers of spots in the ‘brain visual areas’. The main research question for the team was, ‘can we fit that many electrodes on an implant with the materials we have and make it small enough and also effective?’ and the answer from this study was – yes,” says Professor Asplund.
 
In the study, mice were trained to respond to an electrical impulse sent to the visual cortex of the brain. Results showed that mice could learn to react to the stimulation in a few sessions. Also, the implants remained functional and stable over time. 
 
The research has been published in Advanced Healthcare Materials. It is written by Corinne Orlemann, Christian Boehler, Roxana N. Kooijmans, Bingshuo Li, Maria Asplund and Pieter R. Roelfsema. The authors are active at the Netherlands Institute for Neuroscience, the University of Freiburg, and Chalmers University of Technology.