If you mean to say that you want to do MTT assay of some compound loaded on micro emulsion then Yes there is a good amount of literature available for that a few ref. can be
1. Evaluation of protective effect of a water-in-oil microemulsion incorporating quercetin against UVB-induced damage in hairless mice skin.J Pharm Pharm Sci. 2010;13(2):274-85.
2.
Capacity of natural β-carotene loaded microemulsion to protect Caco-2cells from oxidative damage caused by exposure to H2O2 S. Roohinejad et al Food Research International 66 (2014) 469–477.
3.Docetaxel microemulsion/Asian Journal of Pharmaceutical Sciences 2009, 4 (6): 331-339
however if you want to check the MTT of only micro emulsion then you have to be sure of the non toxic nature of micro emulsion itself.