Brain Machine Interfaces (BMIs) promise to improve the lives of many patients by providing a direct communication pathway between the brain and one or more external devices. As the brain is an electrochemical system additional signals may improve BMI performance beyond direct electrical signals. Further many psychiatric and neurological disorders such as Parkinsons disease, depression, dystonia, or obsessive compulsive disorder are related to neurotransmitter deficiencies or imbalances. Accordingly detection of neurotransmitter chemicals and/or management of these chemicals may enhance BMIs. Embodiments of the invention provide for implantable CMOS based target derived neurotrophic factor delivery microsystems and neurochemical sensors allowing neurotransmitter deficiencies or imbalances to be detected, monitored, and corrected. Such implantable CMOS solutions provide for high volume, low cost manufacturing as well integration options in arrayed formats as well as integration with other CMOS electronic circuits.
