title: Development of an artificial synapse using an electrochemical micropump.
abstract: Improving the resolution of artificial sensory organs requires an interface that receives external information from electronic circuits and stimulates appropriate neurons individually in response to that information. The method of electric stimulation in available artificial sensory organs is fairly nonselective; therefore, we developed a method of chemical stimulation of neurons using a neurotransmitter containing an electrochemical micropump powered by the bubbling that occurs during water electrolysis. The micropump contains a glass nozzle with a tip 10 microm in diameter. Two blackened platinum electrodes for the electrolysis were inserted into the body of the pump, which was filled with neurotransmitter solution. The distance between a neuron of the gastropod Aplysia and the tip of the nozzle was adjusted to about 100 microm. A potential difference of 3.0 V was applied to the electrodes to propel the solution toward the neuron while its membrane potential was monitored. Administration of 1-mM acetylcholine to a resting neuron caused neural firing only when the voltage was applied for 0.5 s and without a time lag. During administration of 50-mM gamma-aminobutyric acid to spontaneously firing neurons, the firing disappeared with a time lag of 1 s after application of 3.0 V. We concluded that an electrochemical micropump can be applied for rapid neurotransmitter administration to control the excitation and inhibition of neurons. This simple pump can be miniaturized to create "synapses" in artificial sensory organs.
authors.affiliation: Department of Applied Chemistry, Shibaura Institute of Technology, 3-9-14 Shibaura, Minato-ku, Tokyo, 108-8548, Japan. yosimi@sic.shibaura-it.ac.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshimi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Shinoda
authors.forename: Masatomo
authors.initials: M
authors.lastname: Mishima
authors.forename: Kenta
authors.initials: K
authors.lastname: Nakao
authors.forename: Kohta
authors.initials: K
authors.lastname: Munekane
mesh_terms: D000818:Animals; D001698:Biomedical Engineering; D004594:Electrophysiology / Q000295:instrumentation*; D007448:Invertebrates; D008564:Membrane Potentials; D023421:Models, Animal; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D018377:Neurotransmitter Agents; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission
chemical_list: D018377:Neurotransmitter Agents