Carbon Nanotubes As Photoluminescent Quantitative Bioanalytical Sensors

Real-time, spatially resolved detection and identification of analytes in biological media present important goals for next-generation sensors. To this end, the intrinsic near-infrared fluorescence of single-walled carbon nanotubes can be modulated by their immediate environment.  The encapsulation of nanotubes in synthetic polymers and biopolymers creates a handle for the transduction of analyte binding.  Small molecules, such as reactive oxygen species and other genotoxins, can be detected by transduction of the binding event to the polymer or the nanotube itself.  In these cases, small molecule analyte identification is achieved by observing variations in the nanotube’s spectral response, resulting in distinct optical fingerprints.  Nanotube emission can undergo both wavelength and intensity modulation, permitting the identification of analytes which are difficult to differentiate via conventional methods.  The responses can be spatially mapped in live cells and tissues, and measured in real-time with sensitivity down to the single-molecule level, facilitating unprecedented bioanalytical studies.