[youngWoody]

Hi,
I'm fairly new to carbodiimide crosslinker chemistry and am currently trying to conjugate a polymer with a carboxyl acid-endgroup to the surface of primary amine-containing nanoparticles. I need to do the conjugation in an organic solvent, like dichloromethane, as the polymer is hydrophobic.

My question is, do I actually need hydroxysuccinimide (NHS) for this type of reaction?

Would greatly appreciate any thought on this from someone.

Thank you!

[kriggy]

What conditions are you want to use? NHS is used as an activating agent that forms an active ester with the acid then can then react with amine to form an amide. You can use different activating agents like HOBT.
You might get away with just using carbodiimide but Im not realy sure.

[youngWoody]

What conditions are you want to use?

Thanks for your reply.

This is a simple version of my reaction protocol:

1. Dissolve hydrophobic HOOC-Polymer in DCM and purge with nitrogen
2. Dissolve DCC in DCM and purge with nitrogen
3. Add DCC solution to HOOC-Polymer DCM solution
4. separately disperse aminated nanoparticles in DCM and purge with nitrogen
5. add nanoparticle dispersion to DCC/HOOC-Polymer solution
    -> react over night
6. centrifuge particles and remove supernatant (which should contain the Dicyclohexylurea) and redisperse in DCM (repeat 3 times)

You can use different activating agents like HOBT.
You might get away with just using carbodiimide but Im not realy sure.

What would be the advantage of HOBT over DCC?

[kriggy]

You use both, DCC+HOBT or DCC+HOsu.You can also use different diimide. I have very limited experience with this you you might want to try it yourself.

[TheUnassuming]

Yeah, if your nucleophile is hot enough you can get away without a catalyst like NHS/HOBt/DMAP, but your yield will always be better with the catalyst.