The lipids are going away from the chitosan surface and form structure of their own (because they are only adsorbed) , liberating the cationic chitosan or you are not using the same buffer to dilute, then the ionic strength of the buffer changes and the zeta potential too.

I have used millipore water to dilute the nanosuspension.....what could be the best way to confirm the above........can you suggest me any simple analytical technique to find out whether chitosan and lipid particles are getting away fron each other........

when you dilute your suspension with millipore water you also dilute any electrolytes you find in your mixture (if there are any) that shield the nanoparticle's charge. When the charge is less shielded, you will find increased values for your zeta potential. You should try to dilute them in a medium with a defined set of electrolytes (like 1 mM NaCl). That could help you negate dilution effects.

Dilution of your sample without buffer media is the major reason to increase zeta potential of particles. Nanoparticles already has higher surface charge capacity. That was stabilized by background electrolyte. When you dilute the media, it also dilute your background electrolyte. Then nanoparticle must have to do something to stabilized it charges. Normally nanoparticles will agglomerate to reduce it. In your case, it remove cationic chitosan to stabilized. You can test your solution media for chitosan. Then you can get clear idea about it. I suggest, the best way to do dilution is in buffer media.

Dear All,

there is no electrolyte or surfectants used for the nanosuspension preparation, only electrostatic interactions between the two polymers forms the basis for the formation of nanoparticles in the medium.in addition if chitosan is forming structures of their own in that case size istribution should show two peaks one of the nanoarticles and other of the chitosan micelles if any.........this has not been found in size distribution for more than 15 day or so........again if i dont dilute the suspension and directky put the suspension fr charge measurement then it tells poor signals due to more concentrations...........it is necessary for me to dilute the suspension as sample is colored.so what could be the best way to measure the charge in the abve circumstances............dilution with nacl will not have any effect on the absolute charge of the particles frmed??? please suggest

hi, lokesh, Do you understand this phenomena. because i have the same problem when i try to coat the chitosan with lipid. so if you reach to a solution please till me