MIC against which organism? Bacteria ?

I'm not an expert of zinc oxide and I do not know if you need some special conduction (e.g. ph or solvent) to make it soluble.

regarding the mic test as general consideration i f your drugs is not able to perform inhibition in one concentration range where the turbidity is not detectable probably the only way is use a different layout to determine cell viability and therefore the mic.

for example you can use

1) xtt assay. live cells will release a orange compounds into the media and also if you have turbidity due to the zinc and the.cells you can remove all the particles by centrifugation before read the absorbance.

in this case you need to carefull select the bacteria inoculr to be just under the xtt detection limit so you will not obtain any colour at high concentration where the growth is inhibited while you will obtain different intensity when the drug concentration decrease.

2) perform cell viability count by plating serial dilution in lb agar plates

those methods are more time expensive respect than standard mic but probably more reliable in your case.

pay attention to add to much dmso because otherwise you may determine also its antimicrobial activity.

good luck

Manuele

Can you simply spin down the ZnO? In many tests for live cells (like MTT), the dye produced is extracted with acid propanol, and only the clear supernatant is measured.

only the clear supernatant is measured. filtration of insoluble part or transfer your work to nanoparticles protcol