Problem
You have genetically altered a cell line so that it expresses the gene BLUE, which encodes for a blue pigment molecule. When the BLUE pigment is present cells (shockingly) appear blue, while normal cells are translucent (i.e., clear).
You grow your cells on a specialized 'plate'. When you add the cells to the specialized dish/plate, the cells will grow in a layer on top of the plate. You can attach miRNAs to this plate before adding your cells. Cells that are growing/living over areas with the miRNA will absorb the miRNA and the miRNA will be able to function within that cell.
You attach miRNA targeted to BLUE to a central 'dot' on your plate (see diagram; the 'dot' is the coloured circle). Only this one 'dot' has miRNA, the rest of the plate does not. What colour do you expect the cells to be that grow on the 'dot'? Why?