Dear Researchers,

I am currently working on conjugating solid lipid nanoparticles (SLN) with hyaluronic acid (HA). However, I encountered precipitation issues during the conjugation process.

I dissolved 12 mg of hyaluronic acid in 6 ml of water and prepared an activation solution by adding 6 mg of EDC in 2 ml and 4.5 mg of NHS in 2 ml. The activation reaction was conducted at 20 degrees Celsius for 3 hours. Then, I added the SLN dispersion (20 ml in water) to the activated HA solution. The reaction mixture was left under mild rpm conditions at the same temperature for one day.

During the reaction, a white-colored and less dense precipitate formed in the solution, indicating potential incomplete conjugation or other issues.

I used EDC and NHS as coupling agents. However, the observed precipitate suggests that further optimization is required to achieve successful SLN-HA conjugation.

I would greatly appreciate any insights into the causes of this precipitation issue and any suggestions for improving the conjugation process.

Additionally, if you have any alternative methods for conjugating SLN with HA or recommendations for characterizing the resulting conjugates, your input would be highly valuable.

Thank you for your time and expertise. I eagerly await your input.