Multichannel Systems MEA Quick Guide - Manual (Page 2)

MEA Cleaning and Storage
Cleaning the MEAs
Prepare a 1% solution of Terg-A-Zyme (Sigma, order number Z273287), diluted in distilled water. Place
MEAs in this solution overnight at room temperature. Apply gentle shaking or rocking, if possible. After
Terg-A-Zyme treatment, rinse thoroughly with distilled water. Terg-A-Zyme solution can be stored at 4 °C
and reused for about a week. Dry the MEAs and apply hydrophilic surface treatment (see below), if
necessary. If they are going to be used for cell or tissue culture, autoclave the MEAs at 121 °C for 30 min.
Furthermore, it is advisable to keep track on the accumulated time a MEA spend in cell culture, and the
number of cleaning procedures it went through. Do not fix cells or tissue on the MEAs. Detergent
treatment will not remove fixed tissue.
NEVER wipe or otherwise touch the electrode field.
Warning: It is absolutely necessary to rinse the MEAs thoroughly with distilled water after
treatment with detergent, particularly when using Terg-A-Zyme before dry-heat sterilization
(dry-heat sterilization is not recommended). Otherwise the potential rests of the detergent
may burn into the glass carrier of the MEA and may destroy the electrodes.
Cleaning the MEA contact pads
Dirt on the contact pads of the MEA or on the pins of the MEA amplifier leads to bad contact and electrical
noise. Pins and contact pads can be cleaned by wiping them with ethanol or isopropanol.
Storing the MEAs
It is recommended to store the MEAs in distilled water in the fridge. After use, remove biological material
with water. MEAs should be stored in this condition and completely cleaned (see above) immediately
before the next use. Change the water the MEAs are stored in at least once a month.
Hydrophilic Surface Treatment
The surface of new MEAs is hydrophobic, and even hydrophilic MEAs tend to become hydrophobic again
during storage. A hydrophobic surface prevents attachment and growth of the (hydrophilic) cells.
Plasma Cleaning
Laboratories with access to electron microscopy facilities are likely to have a sputter device or a plasma-
cleaning chamber (for example PDC-32G from Harrick Plasma, Ithaca, NY, United States). MEAs can be
treated in these chambers with low-vacuum plasma for about two minutes. The MEA surface is exposed to
a gas plasma discharge, which will make the surface polar and thus more hydrophilic. The treatment gives
a very clean and sterile surface that can be coated readily with water-soluble molecules. Note that the
effect wears off after a few days.
Protein Coating
If plasma treatment is not available and protein coating is acceptable in the planned experiments, there
is another way to render the surface hydrophilic. Clean and sterilize the MEAs as described above. Place
approximately 1 ml of a concentrated, sterile protein solution (for example, albumin, fetal calf serum or
similar) onto the culture region for about 30 min. Wash the culture chamber thoroughly with sterile water
afterwards. The MEA can then be directly used for cell culture.
This is just a quick guide. For complete information about MEA handling please refer
to the MEA Manual.