This is not entirely a matter of monitoring sugar uptake, since there are extracellular disaccharidases- sucrase, which will lead to release of extracellular glucose and fructose that can be transported independently of sucrose- So you need to use a sucrase inhibitor such as "Rat intestinal sucrase inhibition of constituents from the roots" of Rosa rugosa Thunb.Bioorganic & Medicinal Chemistry Letters 24 (2014) 1192–1196 Thao et al, then use radiolabelled sucrose to monitor uptake to show that what you are looking at is in fact sucrose transport. It would be useful then to extract the cell contents and run on thin layer chromatography or a similar techniequ to see if you have in fact transported sucrose, rather than glucose or fructose.