Hello
I have synthesized gelatin type A nano-particles by two-step desolvation. After 4 days of freeze-drying, the powder was kept in the freezer (-80 C). Today I tried to redisperse the nano-particles in the water and 20mM NaOH by vortex and homogenizer. The problem is that I saw sediments in the solution and it was kind of cloudy. The DLS result showed sedimentation and the data was not meet the criteria of an appropriate sample. Can you please help me what is the problem with that? How can I redisperse the gelatin nanoparticles in the water?
I have used prob sonicator and the problem still exists.
Best Respects.
@Gelareh Rezvan the nanoparticles can't be redispersed easily once they are dried. The best way to keep them is in a liquid form protected in a solution.
Gelareh Rezvan
Two-stage desolvation is a slow process of nanoparticle formation with a long relaxation time of polymer chains. In redispersion, you use a fast process with the introduction of a lot of energy into the system. When redispersing, use the slow equilibrium in the system as well.
I guess it would be somehow similar to hornification phenomenon, which occurs during dehydration of nanocellulose. A sort of irreversible collapse.
Try ultra-sonic treatment or... perform the synthesis again!
Dear Dr. Xuhua Wang
Thank you for sharing your opinion with me. The reason that I should dry the Gelatin NP is that I want them to make gel and the final composition is important in this case.
Dear Dr. Yuri Mirgorod
Thank you for your advice. It looks like the particles lose their structure or get stacked during the freeze-drying. I have tried to give them enough time. I let the dried particles soak in 20 mM NaOH solution for 3 days under stirring. They don't redisperse.
Dear Andrea Maio
Thank you for sharing your opinion. I think you are right and the particles collapsed during the freeze-drying. I have done the procedure 3 times and I have faced the same problem. The Ultrasonic destroyed the particles, due to the DLS results. I am not sure what I can do regarding this problem.
Gelareh Rezvan
Aggregation of gelatin molecules also occurs when heated. We were convinced of this by ultrafiltration of gelatin solutions. The pores of the membrane filter were quickly blocked by larger particles.
Dear Gelareh Rezvan
you should repeat the synthesis of gelatin, thereby storing it WITHOUT PERFORMING ANY FREEZE-DRYING. Thereafter, you might operate solvent exchange whether you are forced to use any other solvent.
Since I have no expertise about gelatin, I'm not sure that it could be the solution but it could be an option.
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