Hi everyone,
I am trying to bind my antibodies on the gold nanoparticles covered with carboxy-PEG (displaying a carboxyl group on top). Because of that, I am using the EDC/NHS approach, and so far I wasn't able to detect my antibody on the surface. I thought it was because the reaction wan't occurring (i know that EDC/NHS is quite unstable) but actually the problem is that one single antibody is attached by several gold nanoparticles, inducing at the end their aggregation. Since I couldn't find anything about it in literature, I am wondering if this is just my problem and in case if someone has any suggestion to solve it.
Since you use gold NPs, you need to find their zeta potential. This will give you an insight, whether the NP aggregation comes from gold NP themselves or due to EDC/NHS coupling.
EDC/NHS sucks. The hydrolysis of the reactive nhs moiety (if it exists) is the enemy, even if you just use edc. The other thing is that the stability of your system is being perturbed even in the presence of peg. Peg-cooh has not worked for me in terms of particle stabilization, only peg-nh2. I quit working with edc with or without nhs a long time ago. Better results are obtained using glutaraldehyde to react amino groups.
Hello,
Can you provide more details on your reagents ? I am working with EDC/NHS on PEGylated gold NPs, I may be able to provide you with some tips, if you are still working on that. What NP size and PEG length are you working with ?
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