On-chip controlled release of neurotransmitter molecules

The coupling between neurons and microelectronic devices becomes more and more a subject of intensive research. It finds applications in domains such as neurophysiological research and implants. In those applications, efficient stimulation of neurons is extremely important. The currently used methods are based on electrical stimulation, and show low efficiency and reproducibility. Chemical stimulation is a promising alternative method, which requires the local and controlled release of neurotransmitter molecules in order to stimulate individual neurons separately. This paper describes the fabrication and characterization of a device capable of releasing chemical compounds, in particular charged neurotransmitter molecules. Electrokinetic actuation is used to release l-glutamate molecules locally on top of a chip. The release is detected optically using an enzymatic detection kit. Numerical simulations of the device operation are used to predict the behavior of the system. Such a device is potentially useful in the research of neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. In a broader context, this device can be used to release locally small amounts of chemical compounds, among others in Lab-on-Chip and drug delivery applications.