Detection limit of biomarkers using the near-infrared band-gap fluorescence of single-walled carbon nanotubes

Progress is being made in the development of microanalytical systems for biosensing. Because the sensor signal-to-noise ratio increases with decreasing size for many devices, considerable effort to fabricate small sensors is going to be addressed. Due to their hollow cylindrical structure, carbon nanotubes (CNTs) are considered very promising for many potential nano-device applications. Fluorescence microscopy in the near-infrared (NIR) between 950 and 1600nm has been developed as a novel method to image and study single-walled carbon nanotubes (SWNTs) in a variety of environments. Recently, hybridisation of DNA using NIR band-gap fluorescence has been experimentally demonstrated. We describe a numerical simulation, where the fluorescence shift energy is connected to exciton density variation when the molecular recognition is located on the SWNT immersed in a physiological solution.