The fluorescence of green fluorescence protein (GFP) decays according to the data given in the table below. Determine the fluorescence lifetime, (b) Flavin adenine dinucleotide (FAD) has a fluorescence lifetime of 2.91 ns in the intercellular medium but < 0.01 ns when protein-bound. FAD is protein-bound in normal epithelium but free in some precancerous tissue. Discuss how this difference in lifetimes can be used in imaging to distinguish precancerous cells from non-cancerous cells.

t/ ns 0.8 78.2 3 39.7 10 4.61 0.5 1.5 85.7 63.0 21.5