Dear Samiah Mahboob, please check the following documents. My Regards

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4686320/

https://www.peertechz.com/Nanomaterials-Nanotechnology-Nanomedicine/IJNNN-3-113.php

Dear Samiah Mahboob, please check the following documents. My Regards

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4686320/

https://www.peertechz.com/Nanomaterials-Nanotechnology-Nanomedicine/IJNNN-3-113.php

@ Samiah, normally repeated washing and dilution before DLS may help to reduce PDI value.

Dear Samiah Mahboob, apart from the repeated washing and dilution of the target solution, PDI value and zeta potential depend on your developed formulation quality. The particles should be uniform sizes throughout the solution.

Please have a look at my work, thanks

Article Development of nanoemulsion formulation of mustard oil, its ...

Effective sonication is very important for dispersion. Consider a reproducible method afforded by a sonication probe like that developed in the Nanoreg project

Dear Researcher,

The sort of problems such as the unsuitable synthesis method used for providing this nanoparticle, using irrelevant kind of nanoparticle solution, lack of using the appropriate refractive index of DLS device for the nanoparticle-containing solution, lack of sonication of nanoparticle before DLS test and so forth could be involved in this issue.

Hi Samiah

Repeated washing and dilution should help solve the problem. However, if this approach fails, then you can go for effective sonication using a probe for about 2 to 3 minutes. I had similar experience and this approach worked for me.