I am attempting to perform a permeability assay. I have tried dextran-Alexa647 10kDa. However, after long term treatment (24hrs), the cells dont seem healthy (with large vacuoles or vesciles and cell deat debris). It has been reported that 'small' dextran infers osmotic stress on cells. Since, my experiment involves long term imaging, I was wondering if there is an alternative probe instead of dextran. I have came across PEG, but not clear, especially on its application in monoloayer and multilayer epithelium.

Does anyone have a suggestion? any comments or suggestions will help.

Thank you