Dye concentration was 5 µM in DMSO or PBS, pH 7.4, and measurements were obtained at room temperature. Dyes were excited using a 375 nm Nano LED (Horiba Scientific Inc.). Emission for ICB was collected at 700 nm and for ICG at 800 nm. The decay profiles for ICB were treated as mono-exponentials but the ICG profiles exhibited a bi-exponential trend as the photoluminescence decay of ICG in PBS pH 7.4 and H2O were closer to the instrument response function (IRF) of the time-correlated single photon counting setup.