Hello Nishit Pathak

There are two issues you need to consider when you are studying drug uptake by C. elegans using NGM agar plate.

1. NGM is a highly complex mixture of two undefined compounds (agar and bactopeptone) that could interfere with drug uptake. The high concentrations of small molecules present in bactopeptone could decrease the solubility of drugs in NGM, leading to precipitation of the drug in the plates, which can sometimes be visually seen as “crystal gardens”.

In NGM, the drug can be either mixed into the molten agar or later added as a solution on top of the solidified agar. Factors such as humidity, interactions of the drug with the agar and solubility of the compound can all potentially influence the real level of exposure of the worms to the drug. Supplementing the drug into molten NGM may cause degradation of the compound due to high temperature. If the drug is added as a solution on the surface of the agar plate, it will inevitably take time for the drug to diffuse through the solid medium. Some investigators incubate plates, on which the drug has been added as a liquid solution, for 6–24 h before transferring the worms. Drug uptake by worms grown on NGM plates may sometimes be absent. In contrast, liquid medium could provide a much more controllable dosing environment.

2. C. elegans has an impermeable cuticle that forms a strong barrier for the absorption of many drugs. Mutants have been created that have a more permeable cuticle, which should allow for easier absorption of exogenously added compounds in drug screening and toxicity testing. C. elegans also has an extensive enzymatic detoxification system and likely contains xenobiotic efflux. All these make drug absorption in C. elegans limited.

To overcome uptake problems, studies in C. elegans often use very high drug concentrations compared to studies in mammalian cell culture. However, the use of high drug concentrations adds expense and could lead to problems such as lack of solubility of some compounds. To increase uptake efficiency of hydrophilic compounds, they can be loaded into liposomes before administration to C. elegans.

You could refer to the research article attached for more details. It will be helpful for your assay.

Article Phenotypic Screening in C. elegans as a Tool for the Discove...

Best.

You could use microinjection if you have the capabilities.