Near infrared fluorescence lifetime imaging of biomolecules with carbon nanotubes

09 January 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Single wall carbon nanotubes (SWCNTs) are versatile building blocks for biosensors. Their near infrared (NIR) fluorescence enables detection of biomolecules in the optical tissue transparency window. The fluorescence intensity of SWCNTs changes in response to an analyte and this interaction can be chemical tailored by the surface chemistry. However, optical signals based on intensity are affected by external factors such as sample movement or fluctuations in excitation light. Here, we demonstrate fluorescence lifetime imaging microscopy (FLIM) of SWCNT-based sensors in the NIR as calibration-free method. For this purpose, we tailored a confocal laser scanning microscope (CLSM) for NIR signals (>800 nm) and employed time correlated single photon counting (TCSPC). (GT)10-DNA functionalized SWCNTs are then used as sensors because they increase their fluorescence (995 nm) in response to the important neurotransmitter dopamine. Their fluorescence lifetime (> 900 nm) follows a biexponential decay and the longer lifetime component (370 ps) changes with dopamine concentration. It increases by up to 25 % with detection limits in the nM range. These sensors serve as paint to cover cells and report extracellular dopamine in 3D via FLIM. We therefore show the potential of using fluorescence lifetime in combination with confocal microscopy as readout for SWCNT-based sensors.


fluorescence lifetime
confocal microscopy
single wall carbon nanotubes

Supplementary materials

Supplementary Material: Near infrared fluorescence lifetime imaging of biomolecules with carbon nanotubes
The Supplementary Material contains in detail Materials and Methods of performed experiments and additional figures of the sensor characterization.


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