Monitoring lysosomal activity in nanoparticle-treated cells

Certain nanoparticles have been shown to accumulate within lysosome and hence may cause lysosomal pathologies such as phospholipidosis, lysosomal overload, and autophagy. This chapter describes a method for evaluation of lysosomal activity in porcine kidney cells (LLC-PK1) after exposure to nanoparticles. This method uses the accumulation of a cationic fluorescent dye (LysoTracker Red) in acidic cellular compartments as an indicator of total lysosome content. The lysotracker signal is normalized to the signal from a thiol-reactive dye which is proportional to the total number of viable cells.