A review of Microelectrode Array technologies: Design and implementation challenges

The emerging field of neuroprosthetics is focused on design and implementation of neural prostheses to restore some of the lost neural functions. Remarkable progress has been reported in the various brain-machine interfaces (BMIs) but the electrode-tissue contacts remain one of the major obstacles. The success of these BMIs relies on electrodes which are in contact with the neural tissue and act as an interface between tissue/ sensors or tissue/ bio-microelectromechanical systems (bio-MEMS). In recent years, Microelectrode Arrays (MEAs) fabrication techniques have been developed to have a long-term and stable interface with the brain. So far, none of these attempts have lead to a major breakthrough. In this paper, we review different microfabrication techniques of MEAs with their advantages and drawbacks. Then, we propose high-density, three-dimensional (3D), silicon-based MEAs using micromachining methods. The geometries that will be used include arrays of penetrating variable-height probes.