The intrinsic near-infrared photoluminescence of semiconducting single-walled carbon nanotubes exhibits environmental sensitivity which has been employed to detect various analytes in complex environments, including biological media. To build biomedical technologies that employ carbon nanotube photoluminescence, a better understanding of the optical response, as well as new methods to measure it in biological systems, are needed. We have developed new imaging platforms to quantify nanotube emission, including a method to conduct photoluminescence excitation/emission spectroscopy on living samples. We are also exploring ionic screening phenomena during ambient pseudocapacitive charging as a modulator of nanotube photoluminescence for electroanalytical measurements in biological media.