The Becker & Hickl DCS-120 MP multiphoton FLIM system combines metabolic imaging by NAD(P)H with pH imaging by BCECF (2′,7′-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein). The system uses a femtosecond fibre laser with an emission wavelength of 785 nm. Two-photon excitation with this laser excites both NAD(P)H and BCECF at reasonable efficiency. The fluorescence of the two compounds is split spectrally on the emission side and recorded in two parallel TCSPC FLIM channels. Analysis by bh SPCImage NG delivers one lifetime image for the metabolic state and another for the pH of the tissue. An example for mammalian skin is shown below.
