The epsilon-amino group of lysine can be reacted with various chemical probes. For example, you could treat the surface with fluorescein isothiocyanate (FITC), which will react with the lysine side chains and make the surface fluorescent. Obviously, it is important to check for background with a similar surface not exposed to polylysine. A mildly alkaline pH is desirable for both the reaction and the fluorescence measurement. The buffer for the reaction should be amine-free, such as fresh 0.1 M sodium bicarbonate.

Mrs/Miss Swietek,

Via MS.

Thank you!