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.

In Vitro Microfluidic Models for Neurodegenerative Disorders

“…One could explore uses of such microfluidic systems in the future to discover therapeutics for neurodegenerative diseases. The 2D‐based CMS has the advantage of easy application of electrical and optical stimulation and easy quantification, for instance, by incorporating electrodes on the bottom of the chamber to quantitatively measure neuronal signals.…”

Advances in microfluidic in vitro systems for neurological disease modeling

“…(d) Physical guidance of axons through microchannels, and integration of electrodes for cell monitoring and stimulation. (Reproduced from Jang et al., 2016 with permission from The Royal Society of Chemistry.) (e).…”

Advances in ex vivo models and lab-on-a-chip devices for neural tissue engineering

“…Electrodes on the chips can also be used to optically stimulate neurons in the device with either one-or two-photon lasers [206]. In a device created by Jang et al (2016), a PDMS microfluidic device previously described by other authors [184] was coupled with microelectrode arrays that were placed underneath the device to obtain separate readings from soma and axons (Fig. 6, "Optical Stimulation") [206].…”