(4da) Carbon Nanotubes as Optical Sensors and Polymeric Biomaterials

Real-time, spatially resolved detection and identification of analytes in biological media or at the single-molecule level present worthy challenges for nanoscale sensors. Encapsulation of nanotubes in synthetic polymers and biopolymers creates a handle for the transduction of analyte binding. Encapsulation in short sequences of ssDNA allow detection of reactive oxygen species (ROS) via specific interactions with DNA, while nitroaromatic compounds are detected by the conformational change of a peptide. In both cases, analyte specificity is possible by variations in the nanotube response, resulting in distinctive optical fingerprints. Solvatochromic shifts of up to 50 meV and intensity modulation permit identification of analytes which are traditionally difficult to differentiate, such as certain ROS species. Single analyte molecules are detected via quantized quenching or solvatochromic shifting of the nanotube emission, permitting spatial mapping of analytes with unprecedented sensitivity.