Title: Fluorescent single-walled carbon nanotubes for imaging and sensing in the near-infrared

Abstract

Single-walled carbon nanotubes (SWCNTs) have unique optical and physical properties, and they benefit from the ease of surface functionalization and biocompatibility. Semiconducting SWCNTs fluoresce in the near-infrared (nIR) part of the spectrum, which overlaps with the transparency window of biological samples where absorption, scattering, and autofluorescence are reduced. Further, they do not photobleach or blink. Upon tailored surface functionalization, adsorption of target analytes onto the nanotube corona can result in spectral modulations manifested as either an intensity change or a shift in the peak emission wavelength. Hence, SWCNTs can be used as nIR optical probes for imaging and sensing in biological samples enabling real-time optical detection with both spatial and temporal resolution. I will present recent discoveries of protein nanosensors for fibrinogen and insulin using SWCNTs functionalized with variants of poly(ethylene glycol)1–3. The recognition also occurs in serum environment, showing that the SWCNTs sensors work in this complex environment despite the potential nonspecific adsorption. I will show recent demonstrations of real-time feedback on insulin secretion by beta-cells4, real-time monitoring of enzymatic activity5, and recognition of a cellular oncometabolite6. Finally, I will present in vivo imaging of fluorescent SWCNT within nematodes7, and super-resolution imaging of SWCNT8. These results open new avenues for synthetic recognition of biological macromolecules with optical signal transduction, and hold great promise for medical and clinical applications.