Ratiometric imaging of catecholamine neurotransmitters with nanosensors

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

Abstract

Neurotransmitters are important signaling molecules in the brain and relevant in many diseases. Measuring them with high spatial and temporal resolution in biological systems is challenging. Here, we develop a ratiometric fluorescent sensor/probe for catecholamine neurotransmitters based on near-infrared (NIR) semiconducting single wall carbon nanotubes (SWCNTs). Phenylboronic acid (PBA)-based quantum defects are incorporated into them to interact selectively with catechol moieties. These PBA-SWCNTs are further modified with polyethylene glycol phospholipids (PEG-PL) for biocompatibility. Catecholamines including dopamine do not affect the intrinsic E11 fluorescence (990 nm) of these (PEG-PL-PBA-SWCNT) sensors. In contrast, the defect-related E11* emission (1130 nm) decreases by up to 35%. Furthermore, this dual-functionalization allows tuning selectivity by changing the charge of the PEG-polymer. These sensors are not taken up by cells, which is beneficial for extracellular imaging and they are functional in brain slices. In summary, we use dual-functionalization of SWCNTs to create a ratiometric biosensor for dopamine.

Keywords

Biosensors
near-infrared fluorescence
neurotransmitter
dopamine
carbon nanotubbes
quantum defects

Supplementary materials

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Supporting Information
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The Supporting Information includes details of materials and methods, additional spectra, videos, calibration curves, bright field images of a brain slice (PDF).
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Supporting Information_Video M1
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The video records dopamine imaging with PEG-PL-PBA-SWCNTs in organotypic cortico-hippocampal brain slices
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