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.
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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Title
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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