Name: Applying Microfluidics to Electrophysiology (Video) | JoVE Journal
Uploaded: 2007-10-01T00:00:00.000+00:00
Duration: 5 min 41 s
Description: Learn microfluidic techniques for precise spatial temporal stimulation of brain slices in electrophysiology. This method enables controlled neurotransmitter delivery to advance neuroscience research.

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5 minutes

applying microfluidics to electrophysiology

Applying Microfluidics to Electrophysiology

Microfluidics can be integrated with standard electrophysiology techniques to allow new experimental modalities.  Specifically, the motivation for the microfluidic brain slice device is discussed including how the device docks to standard perfusion chambers and the technique of passive pumping which is used to deliver boluses of neuromodulators to the brain slice.  By simplifying the device design, we are able to achieve a practical solution to the current unmet electrophysiology need of applying multiple neuromodulators across multiple regions of the brain slice.  This is achieved by substituting the standard coverglass substrate of the perfusion chamber with a thin microfluidic device bonded to the coverglass substrate.  This was then attached to the perfusion chamber and small holes connect the open-well of the perfusion chamber to the microfluidic channels buried within the microfluidic substrate.  These microfluidic channels are interfaced with ports drilled into the edge of the perfusion chamber to access and deliver stimulants.  This project represents how the field of microfluidics is transitioning away from proof-of concept device demonstrations and into practical solutions for unmet experimental and clinical needs.

Microfluidics can be integrated with standard electrophysiology techniques to allow new experimental modalities.  Specifically, the motivation for the ...

My name is Dave Edington. I'm an assistant professor in the Department of Bioengineering at the University of Illinois at Chicago. And the area we work on primarily is applying micro technologies to biomedical applications, specifically using microfluidic devices.And today we're gonna show you one of our projects, which in involves using a microfluidic device that adapts to a standard brain slice perfusion chamber to provide spatial temporal stimulation of a brain Slice. So currently in electrophysiology slice preparations, the main applications of neurotransmitters to a slice are either globally across the entire brain slice. We're stimulating the whole brain slice at one time, or using a micro pipette to puff on neurotransmitters at different time points.The brain slice is a very complex structure, and when you're globally applying neurotransmitters or using a micro pipette, you cannot reproduce in vivo stimulation patterns. Whereas with our platform, we're able to control the stimulation to very specific regions across the brain splice and achieve a more in vivo like Stimulation. So current perfusion systems are shown here where they dock with a standard cover glass slide.And these allow for the media to be perfused across the entire slice. However, you can't spatially control the resolution of that neurotransmitter that your stimulant device with. So we developed a micro flic device that docks with this standard profusion chamber.So all the standard electrophysiology assays can be used. And the only different feature is instead of a glass cover glass bottom, this consists of A-P-D-M-S device that has several through holes that connect to microfluidic channels, that connect to openings on this top profusion chamber that we can then stimulate neurotransmitters through these holes, through the channels, out the vias, and into the brain slice. And we use a technique called passive pumping to deliver the fluids.So we don't need any complex tubing to be coming out of this device because electrophysiology is already a very complex procedure. And by simplifying the device design and using passive pumping, we simplify the experimental protocol of applying this microfluidic device. The structure of the device is a two layer microfluidic network.The first layer is the routing channels that connect to the outlet ports, and the second layer consists of these through holes that connect these channels to the well. So this fabrication is done using standard two layer U microfabrication steps where we have some alignment marks that make sure these vias are positioned directly in the center of these four channels. So this device is designed to dock with the standard profusion chamber, so all the same electrophysiology assays can be used.So we can put this on electrophysiology rig, have our objective come into it, provide local stimulation through our microfluidic channels, and not needlessly complicate the experimental setup beyond more than what it needs. So by keeping the device design as simple as possible, we can disseminate this platform much easier. So our structure right now, we have these four Vs in the middle of our micro fluidic channels, but these can be adapted to different labs needs depending on which region of the brain they're studying.So one region could study the hippocampus and one could study the outer cortex. And so we could stimulate those regions depending on how we design this microfluidic device. And because the device requires no external components to operate, all you need is a micro pipetter to pipette onto these openings using the passive pumping technique.There is no extra equipment beyond this bottom substrate that the standard electrophysiology lab needs to acquire to use This device. So Up to this point in the project, we've been focusing on getting the the microfluidic channels docked with the standard profusion chambers. And now the next part of the project is actually testing this device on actual hypothesis driven research using these slice preparations.And so we've demonstrated that with using fluorescent dye, that we can spatially stimulate different regions by injecting these fluorescent analogs into the channels. And the next step is to actually do the real biological experiments. So the field of microfluidics is coming to a transition point.We're re moving past novel proof of concept demonstrations and really using these devices to discover new and exciting things that were previously impossible to do. So the field is moving from techniques where we've used principles available at the microscale, such as fast diffusion, laminar flow, and large service to volume ratios and process integration. And now we're gonna use those and apply those to solve unmet needs in the lab and in the clinic.

applying-microfluidics-to-electrophysiology

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JoVE Journal

Biology

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Learn microfluidic techniques for precise spatial temporal stimulation of brain slices in electrophysiology. This method enables controlled neurotransmitter delivery to advance neuroscience research.

Applying Microfluidics to Electrophysiology

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