title: One-photon and two-photon stimulation of neurons in a microfluidic culture system.
abstract: In this study, we demonstrate a novel platform for optical stimulation of neural circuits combined with a microfluidic culture method and microelectrode array measurements. Neuron-on-a-chip was designed and fabricated to isolate axons without a soma or dendrite. Thus, it is readily able to manipulate the neuronal alignment and to investigate the neuronal activity at the locations we want to observe. We adapted the optical stimulation technique to the arranged neurons to generate the neuronal signals in a non-invasive fashion. A blue light-emitting diode and a femtosecond laser with 780 nm center wavelength were used for neuronal activation and the corresponding neuronal signals were measured by MEAs at the same time. We found that one-photon light via caged glutamate provoked periodic spiking. In contrast, the femtosecond pulse irradiation generated repetitive firing at constant rates. Response times of one-photon and two-photon stimulation were around 200 ms and 50 ms, respectively. We also quantified neural responses, by varying optical parameters such as exposure time and irradiation power.
authors.affiliation: Department of Neural Development and Disease, Korea Brain Research Institute, Daegu, Republic of Korea.
authors.forename: Jae Myung
authors.initials: JM
authors.lastname: Jang
authors.affiliation: Department of Biomedical Engineering, School of Life Science, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea. wgjung@unist.ac.kr.
authors.forename: Jeonghyeon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, School of Life Science, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea. wgjung@unist.ac.kr.
authors.forename: Hyeongeun
authors.initials: H
authors.lastname: Kim
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, South Korea. njeon@snu.ac.kr and Institute of Advanced Machinery and Design, Seoul National University, Seoul, Korea.
authors.forename: Noo Li
authors.initials: NL
authors.lastname: Jeon
authors.affiliation: Department of Biomedical Engineering, School of Life Science, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea. wgjung@unist.ac.kr and Center for Soft and Living Matter, Institute for Basic Science, Ulsan, Republic of Korea.
authors.forename: Woonggyu
authors.initials: W
authors.lastname: Jung
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000295:instrumentation*; D002469:Cell Separation / Q000295:instrumentation; D002478:Cells, Cultured; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004307:Dose-Response Relationship, Radiation; D004622:Embryo, Mammalian / Q000166:cytology; D004867:Equipment Design; D006624:Hippocampus / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D007091:Image Processing, Computer-Assisted; D056656:Lab-On-A-Chip Devices; D046228:Microarray Analysis / Q000295:instrumentation; D008858:Microscopy, Phase-Contrast; D009474:Neurons / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D010775:Photic Stimulation; D017785:Photons; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D059010:Single-Cell Analysis / Q000295:instrumentation*; D009435:Synaptic Transmission / Q000528:radiation effects*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon