The Nanoscale World

Using Mica

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Marjan Kashfipour posted on Wed, Oct 21 2015 8:20 AM

Dear all

I want to use Mica as the substrate to immobilize polymer on it and visualize it under AFM. is there any body who has worked with Mica before? is there any specific trick in working with Mica? could you please describe from the scratch step by step how to use it?

Thanks

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Top 100 Contributor
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Hi Marjan-

Use a piece of tape to peel off the top and reveal a fresh layer. Apply your aqueous solution to the mica. Potassium ions on the mica surface will easily be displaced by your solution, leaving a negative surface charge on the mica which binds most strongly to biopolymers with cationic side groups (DNA, for example, needs Mg2+ or poly lysine applied beforehand). Rinse with pure water. Dry with N2 or air, and enjoy. 

 

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Top 500 Contributor
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Thank you for your comprehensive comment. my polymer is poly lipoic acid and i doesn't have any cationic head, so should I somehow add a cationic end group to this polymer to make it stable on the mica?  

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Top 100 Contributor
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You can try to treat the mica surface first. Apply a low concentration of poly-L-lysine, then rinse off well with water. This will make it positive. Or, try immersing in MgCl for a couple hours to exchange the K+ ions with Mg2+ ions. Then rinse again. This usually makes the surface positive.

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