Does heater block objectives from reaching MEA glass?

I am interested in using the new thin MEAs (0.17 thickness glass) to image tissue during recording. The tissue will be alive and will need the base heater.

I want to use a microscope objective to project an image, a visual stimulus from a computer monitor, onto retinal tissue.

However, it appears that the opening in the metal heater plate (in the MEA base, on top of which the MEA sits) is too small in diameter to allow certain objectives access to the MEA.

There is also a raised circuit element (part of the heater) which sits right next to the hole in the plate that objectives seem to bump into before reaching the MEA glass.

Is this a problem? Have users reported not being able to reach the MEA glass with the objective? Have you tested this with any objectives that you might be able to report about?

Do you have a different heater element that can be mounted to the black base plate that has a larger diameter opening?

(The hole in the heater plate which allows visualization of the MEA on an inverted microscope of our current MEA60 system (Ser.#055) has a diameter of approximately 8 mm.)

Thank you for any information on this. If you know how any others have solved this problem of projecting an image onto the MEA, I would love to hear about it.

Many thanks,
Rene’ Renteria

Dear Dr. Renteria,

we do offer these heating elements with three different diameters for exactly the reasons you describe. Standard diameters are 8, 12 or 25mm.

You will find those here :
http://www.multichannelsystems.com/products-mea/spare-parts.html

The change is easily done with just four screws, so there is no need to send in the amplifier.

I hope that helps

Thomas

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Dr. Thomas Meyer
Multi Channel Systems MCS GmbH
Aspenhaustrasse 21
72770 Reutlingen
Germany
Tel: +49-7121-90925-42
Fax: +49-7121-90925-11
www.multichannelsystems.com
Amtsgericht Tübingen, HRB 2616

Innovations in Electrophysiology

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Do you find that the heating is accurate and stable for the elements with larger diameter holes, even the 25mm? (assuming use of a typical MEA or of a thin MEA using a perfusion preheater)

Do you have a list posted somewhere of example lenses known to fit with the different diameters? I suppose it would be easy enough for me to make a mock up of the plate and just check it.

Much appreciated! That was exactly what I was looking for, and I had not stumbled across it on the site.

Best,
Rene'

The heating is stable, however, if there is no movement within the well you might happen to have a temerature gradient falling to the center. Og course this problem will not occur if you do have a perfusion running.

As there are lots of possible objectives from various manufacturers we do not have a list of those fitting. However, I think it can be easily measured.
As the heating elements are not too costly and easily changeable you might consider just getting both diameters instead of spending to much time in building a mock-up.

Thomas