I was trying to conjugate dye and PEG onto DBCO functionalized nanoparticles. The dye I use is azide-Cy5 and the PEG is azido-PEG24-NHS. I first react the dye with particles for 1 whole day followed by reacting PEG for another day. However, when I characterized the product there seemed to be no conjugation between the reactants. I'm wondering whether the condition I used was not optimal for the reaction? The concentration of the particles are ~3E-13 M, and I added 3 equivalents of dye and 50 equivalants of PEG. And each reaction was carried out in aqueous solution at room temperature for a day. Should I modify the reaction condition to get better conjugation? Thanks.
The conditions are not right, indeed! Look for a facilitator for the reaction and pH would be one. Perform one step of reaction at a time. Is the conjugation reaction running in situ?
Riaz A. Khan Thanks for your answer! The reaction was running is situ while being contineously stirred with magnetic stir bar. Maybe this time I should try doing one step and characterizing the intermediate at a time. But based on what I saw, there was even no conjugation occuring for the first step, so I might also try changing other conditions, like changing the solvent from DI water to PBS, and increasing the concentrations. Hope it will work this time.
Azides are part of fast chemistry and if step one is not working due to reasons of solvent, temperature, and contamination, need to be clean and clear on these or it won't work! First, confirm the step one and after intermediate product analysis (aliquot also feasible) and if needed, PURIFICATION, proceed to the next step for clean and high yield reaction.
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanostructured Materials
- Nanoparticles