One option could be the addition of an additional molecule or particle that is highly sensitive to its chemical environment and amplifies the response generated during the enzymatic reaction. Such a method would require minimal adaption of assays as the signal amplifier could be added during the read-out step. Carbon nanotubes are cylindrical 1D materials with exceptional optoelectronic properties. Semiconducting single-walled carbon nanotubes (SWCNTs) do not photo-bleach and fluoresce in the near-infrared region (NIR, 870-2400 nm). In this spectral window, the absorption, scattering and autofluorescence of biological samples is reduced. Depending on the application, different spectral ranges are advantageous. Moreover, the fluorescence of SWCNTs is sensitive to the chemical environment. As such, they present an interesting building block for fundamental studies and have been used in a variety of optical and electrochemical biosensing formats.