Introduction: Microelectrode array (MEA) devices, placed in the nervous system to record and modulate neuroactivity have demonstrated success in neuroscience research and neural prosthesis applications. Functionalizing the microelectrode sites on MEAs to enable neurochemical sensing and drug delivery adds additional dimensions of information exchange and presents tremendous potential for understanding neural circuits and treating neurological diseases. This talk will provide an overview of strategies to enable chronic and multimodal neural interfacing.
Materials and
Methods: We use several materials strategies to enable chemical sensing and drug delivery from MEAs. By incorporating nanocarbon into the conducting polymer electrode coating, we achieved direct detection of electroactive species such as dopamine, melatonin, and serotonin. By immobilizing enzymes or aptamers on nanostructured electrodes, we achieved multisite detection of glutamate, GABA, and cocaine. By incorporating nanocarriers into conducting polymer coating, we enabled on-demand drug delivery. To overcome the challenges in chronic neural interface, we use quantitative histology, explant analysis, and 2-photon imaging to uncover the mechanism of sensing/recording performance degradation and revealed biofouling, inflammatory host response, as well as material degradations. Several bioengineering strategies to minimize these failure modes have been explored.
Results, Conclusions, and Discussions: We demonstrated in vivo multisite and multiple analyte detection or neurotransmitter delivery along with neural recording from our multimodal neural probes. Materials and devices that mimic the mechanical properties of the neural tissue significantly improves device-tissue integration. Biomimetic coatings and drug delivery were effective at reducing biofouling and inflammatory responses. These approaches may be combined to achieve long-term and high-fidelity multimodal neural interfacing.
