The Nanoscale World

Imaging Fibronectin with Tapping mode (fixation and tips)

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LeStagiaire posted on Mon, Nov 15 2010 2:40 PM

Ello,

I imaged fribronectin  with the tapping mode in fluid (I acquired

some decent images).  I am now trying to obtain higher quality
images with the tapping mode in ambient conditions (in air).

I was wondering if anyone could give me (or refer to someone who could
give me) advice on the sample preparation.  Do people tend to fix
(e.g. paraformaldehyde) biological samples such as proteins or cells
when performing AFM imaging in tapping mode in ambient conditions (in
air)?

Do you reccommend any particular type of cantilever for such applications?

Any advice at all would be of value and much appreciated

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Answered (Not Verified) replied on Tue, Nov 16 2010 4:26 AM

Dear Lestagiaire,

If getting high resolution images in fluid is what you're aiming at, I strongly recommend SNL or MSNL probes:

http://www.brukerafmprobes.com/p-3693-snl-10.aspx (short thin or short thick levers)

http://www.brukerafmprobes.com/p-3710-msnl-10.aspx (0.6 or 0.1 N/m)

If you use regular tapping mode, try to find a peak between 8 and 12 kHz (not the highest one which is generally around 30kHz). If you image during several hours, don't hesitate to re-tune and re-adjust the working frequency.

I think ScanAsyst mode should also give very good results on this type of sample.

Coming back to your other question, whatever the sample you image in air, you won't need any fixator. This is only required in liquid and in very specific conditions with euk. cells and bacteria but it usually tends to strech the cell and in that case you cannot say you really image the specimen alive, under physiological conditions. In air, as soon as the deposition buffer is removed, the sample (proteins or whatever) will automatically adhere very strongly to the scaffold.

Good luck,

Alex.

 

 

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