Name: fabrication of amperometric electrodes
Uploaded: 2009-05-04T00:00:00
Description: Watch this Scientific Journal Video about Fabrication of Amperometric Electrodes at JoVE.com

We thank Dr. Aaron P. Fox at the University of Chicago, in whose laboratory this protocol was originally designed, and William Roden (Saint Louis University) for further development of protocol.
We thank the Whitehall Foundation and National Science Foundation for support.

Part 1: Carbon Fiber Preparation
<ol>
<li>Cut a bundle of carbon fibers (we use 7&mu;m diameter) at a length that is ~1.25 X the length of the capillary pipette.</li>
<li>Remove the sizing by boiling ~100 mL of acetone in a container and adding the fibers to the hot, boiling acetone for 30 minutes or longer.</li>
<li>Remove fibers from the warm acetone, and transfer to a clean beaker with 50-100 mL of fresh acetone.</li>
<li>Dry fibers by placing the bundle on an open 150 mm Petri dish and airdry overnight. </li>
</ol>...

<ol>
	<li>Mundorf, M. L., Wightman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amperometry+and+cyclic+voltammetry+with+carbon+fiber+microelectrodes+at+single+cells.">Amperometry and cyclic voltammetry with carbon fiber microelectrodes at single cells.</a> Curr Protocols in Neurosci. 6 (14), 1-6 (2002).</li><li>Machado, D. J., Montesinos, M. S., Borges, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Good+practices+in+single-cell+amperometry.">Good practices in single-cell amperometry.</a> Methods in Molec. Biol. 440, 297-313 (2008).</li></ol>

This protocol describes how to generate and cut amperometric electrodes. During amperometric recordings, a carbon fiber electrode is placed against the surface of a secretory cell. Exocytotic activity is observed as amperometric spikes, which indicates the electrochemical current caused by the transfer of electrons after oxidation of the catecholamines. With practice making and cutting amperometric electrodes, noise levels can be greatly improved over many of the commercially available electrodes.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Epoxy Hardener 1,3-phenylene-diamene flakes</td>
<td>Reagent</td>
<td>Sigma Aldrich</td>
<td>P23954-100G04 716AJ</td>
<td>Aliquots are stored in a dessicator and should not be exposed to light.</td>
</tr>
<tr>
<td>Carbon Fibers</td>
<td>Material</td>
<td>Goodfellow</td>
<td>C005725</td>
<td>&nbsp;</td>
<tr>
<td>Micro-Hematocrit Capillary Tubes</td>
<td>Material</td>
<td>Fisher</td>
<td>NC9836768</td>
<td>&nbsp;</td>
<tr>
<td>Epoxy Resin</td>
<td>Reagent</td>
<td>Miller-Stephenson</td>
<td>Epon Resin 828</td>
<td>&nbsp;</td>
<tr>
<td>Dissecting Microscope</td>
<td>Instrument</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Electrode Puller</td>
<td>Instrument</td>
<td>Narishige Japan</td>
<td>PP-830</td>
<td>1st pull = 24.8 degrees C; 2nd pull = 62.7 degrees C</td>
</tr>
<tr>
<td>Oven</td>
<td>Instrument</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>set to 100 degrees F.</td>
</tr>
<tr>
<td>Hot plate</td>
<td>Instrument</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>set to 55 degrees C</td>
</tr>		</tbody>
		</table>
		</div>

fabrication of amperometric electrodes

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we describe the techniques needed to generate low noise (&lt;0.5 pA) electrodes.  The techniques have been modified from published descriptions by previous researchers (1,2).  Electrodes are made by preparing carbon fibers and threading them individually into each capillary tube by using a vacuum with a filter to aspirate the fiber.  Next, the capillary tube with fiber is pulled by an electrode puller, creating two halves, each with a fine-pointed tip.  The electrodes are dipped in hot, liquid epoxy mixed with hardener to create an epoxy-glass seal.  Lastly, the electrodes are placed in an oven to cure the epoxy.  Careful handling of the electrodes is critical to ensure that they are made consistently and without damage.  This protocol shows how to fabricate and cut amperometric electrodes for recording from single cells.

Watch this Scientific Journal Video about Fabrication of Amperometric Electrodes at JoVE.com

Fabrication of Amperometric Electrodes

This protocol describes how to generate carbon fiber electrodes. The electrodes are subsequently used to detect catecholamine release from vesicles with carbon fiber amperometry.

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we ...

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Application of Light-cured Dental Adhesive Resin for Mounting Electrodes or Microdialysis Probes in Chronic Experiments

In chronic recording experiments, self-curing dental acrylic resins have been used as a mounting base of electrodes or microdialysis-probes. Since these acrylics do not bond to the bone, screws have been used as anchors. However, in small experimental animals like finches or mouse, their craniums are very fragile and can not successfully hold the anchors. In this report, we propose a new application of light-curing dental resins for mounting base of electrodes or microdialysis probes in chronic experiments. This material allows direct bonding to the cranium. Therefore, anchor screws are not required and surgical field can be reduced considerably. Past experiences show that the bonding effect maintains more than 2 months. Conventional resin's window of time when the materials are pliable and workable is a few minutes. However, the window of working time for these dental adhesives is significantly wider and adjustable.

In this report, we propose a new application of light-curing dental resins for mounting base of electrodes or microdialysis probes in chronic experiments. This material allows direct bonding to the cranium.

In chronic recording experiments, self-curing dental acrylic resins have been used as a mounting base of electrodes or microdialysis-probes. Since these ...

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Non-fouling PEG silane monolayer was desorbed from individually addressable ITO electrodes on glass by application of a reductive potential. Electrochemical stripping of PEG-silane layer from ITO microelectrodes allowed for cell adhesion to take place in a spatially defined fashion, with cellular patterns corresponding closely to electrode patterns.

The ability to exercise precise spatial and temporal control over cell-surface interactions is an important prerequisite to the assembly of multi-cellular ...

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In this video we demonstrate the technique of soft lithography with polydimethyl siloxane (PDMS) which we use to farbricate a microfluidic device for culturing neurons.

In this video, we demonstrate the technique of soft lithography with polydimethyl siloxane (PDMS) which we use to fabricate a microfluidic device for ...

PDMS Device Fabrication and Surface Modification

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In this video we demonstrate how to use the neuron microfluidic device without plasma bonding.

In this video, we demonstrate how to use the neuron microfluidic device without plasma bonding.  In some cases it may be desirable to reversibly bond ...

Fabrication of the Thermoplastic Microfluidic Channels

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Here we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns.

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using ...

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This video shows how to use a programmable puller to make patch pipettes and sharp electrodes for electrophysiology. The same procedure can be used to make a variety of glass tools, including injection needles.

Glass microelectrodes (also called pipettes) have been a workhorse of electrophysiology for decades.  Today, such pipettes are made from glass capillaries ...

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Micro-drive Array for Chronic in vivo Recording: Drive Fabrication

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Chronic recording of large populations of neurons is a valuable technique for studying the function of neuronal circuits in awake behaving rats. ...

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Despite the fact that electronic pacemakers are life-saving medical devices, their long-term performance in pediatric patients can be problematic owing to the restrictions imposed by a child's small size and their inevitable growth. Consequently, there is a genuine need for innovative therapies designed specifically for pediatric patients with cardiac rhythm disorders. We propose that a conductive biological alternative consisting of a collagen-based matrix containing autologously-derived cells could better adapt to growth, reduce the need for recurrent surgeries, and greatly improve the quality of life for these patients. In the present study, we describe a procedure for incorporating primary skeletal myoblast cell cultures within a hydrogel matrix to fashion a surgically-implantable tissue construct that will serve as an electrical conduit between the upper and lower chambers of the heart. Ultimately, we anticipate using this type of engineered tissue to restore atrioventricular electrical conduction in children with complete heart block. In view of that, we isolate myoblasts from the skeletal muscles of neonatal Lewis rats and plate them onto laminin-coated tissue culture dishes using a modified version of established protocols[2, 3]. After one to two days, cultured cells are collected and mixed with antibiotics, type 1 collagen, Matrigel&trade;, and NaHCO3. The result is a viscous, uniform solution that can be cast into a mold of nearly any shape and size[1, 4, 5]. For our tissue constructs, we employ type 1 collagen isolated from fetal lamb skin using standard procedures[6]. Once the tissue has solidified at 37&deg;C, culture media is carefully added to the plate until the construct is submerged. The engineered tissue is then allowed to further condense through dehydration for 2 more days, at which point it is ready for in vitro assessment or surgical-implantation.

Here, we demonstrate fabrication of collagen-based, tissue constructs containing skeletal myoblasts. These 3-D engineered constructs may be used to replace or repair tissues in vivo. For our purposes, we have designed these as an atrioventricular electrical conduit for the repair of complete heart block[1].

Despite the fact that electronic pacemakers are life-saving medical devices, their long-term performance in pediatric patients can be problematic owing to ...

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Fabrication and Operation of an Oxygen Insert for Adherent Cellular Cultures

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Oxygen is a key modulator of many cellular pathways, but current devices permitting in vitro oxygen modulation fail to meet the needs of biomedical ...