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AFM imaging of 30 ug/ml fibronectin on a glass slide problem

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Answered (Not Verified) This post has 0 verified answers | 5 Replies | 2 Followers

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Paresh posted on Wed, Apr 11 2012 7:37 AM

Hi,

I've tried imaging one of my samples  where I had a glass substrate immersed in a 30 ug/ml fibronectin solution. The glass was just a planar surface. No modifications were made to it. I'm just looking at the protein adsorption on its surface. I already imaged this protein on 21 nm silica nanorough surfaces in liquid mode and the images came out really good. But when I tried imaging on this planar surface using liquid mode, for whatever reason the trace-retrace patterns on the height image were not converging or overlapping at all. They kept on fluctuating even though I changed the peak force set point, the gain, the scan rate, peak force amplitude and lift height. I tried so many things but the height image kept coming out badly/blurred with many trace lines across the image due to the trace-re-trace problem. 

I'm using the BioScope Catalyst AFM using the nanoscope 8.0 software with the 'ScanAsyst +' tips. Fibronectin is about 120 nm in length when fully stretched. Do you have any advice/suggestions?

Thanks a lot

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Answered (Not Verified) replied on Wed, Apr 11 2012 4:30 PM

Did you check if you can get a clean image of your glass surface without the protein in fluid?

Stefan

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replied on Thu, Apr 12 2012 2:51 AM

Hi Paresh,

Can you send me a snapshot of your working pannel showing all the parameters you are using and typical force curves? And maybe some of your recorded images?

You can send them directly to the following address:

alexandre.berquand@bruker-nano.com

Best,

Alex.

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Paresh replied on Thu, Apr 12 2012 3:18 AM

Hi,

I will try imaging the glass slide by itself in liquid mode tomorrow and let you know how it goes. Thanks

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Paresh replied on Mon, Apr 16 2012 1:51 AM

Hi,

i imaged a planar glass surface in liquid and a clean image was obtained. So there's a big problem with imaging the fibronectin protein for whatever reason. I'm having no problems imaging this protein on a 21 nm silica rough surface, but when it comes to a planar surface, it doesn't seem to work.

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replied on Mon, Apr 16 2012 3:05 AM

OK, then you have 2 options:

1) the fibronectin is not properly attached (glass and silica can have different surface chemistry depending on the type of glass you're using).

2) It's clearly a problem of parameter adjustment. This is why I ask you to provide me all the details (cf my last email).

Best,

Alex.

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