I need to use EDC/NHS coupling in my assay and I don't have MES buffer. Does anyone have used other buffers such as PBS? Is is efficient?
MES is recommended or just usually used.
Phosphate can be used, but yields are usually lower.
Borate buffer can be used but will have a basic pH
Avoid Tris (it's full of amines, and will cross react). It is usually used as a quencher, not the main buffer.
When activating carboxylic acids on surfaces, I just used water. I think you can use any buffer so long as the buffering agent doesn't contain -COOH or -NH3 groups.
My answer was not uploaded: You can use any amine-free and basic (higher pH) buffer for the reaction. I often use 0.1 M NaHCO3-Na2CO3, pH 8.9.
I usually use from Tris buffer for conjugation between bio-molecules and nanoparticles. I think that is appropriate buffer.
MES is recommended or just usually used.
Phosphate can be used, but yields are usually lower.
Borate buffer can be used but will have a basic pH
Avoid Tris (it's full of amines, and will cross react). It is usually used as a quencher, not the main buffer.
Hi there,
as I just found out pH 8.9 might not be the best idea, as it says the higher the pH the lower stable is the NHS ester. ("Although prepared NHS or Sulfo-NHS esters are
sufficiently stable to process in a two-step reaction scheme, both groups will hydrolyze within hours or minutes, depending on water-content and pH of the reaction solution. (NHS esters have a half-life of 4-5 hours at pH 7, 1 hour at pH 8 and only 10 minutes at pH 8.6.)) Thermo Fisher Scientific Inc. Maybe the file attached can be helpful.
All the best!
Hi,
The activation buffer should not contain any primary amine or carboxyl groups, as they will compete with the activation reaction. Phosphate and acetate buffers may also reduce the reactivity of the EDC. It is often preferred to use MES buffer at pH 6 for the activation reaction. MES works very well as a coupling buffer.
Regards,
Rahimeh
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