Carbon nano-onions (CNOs) are highlighted as promising agents for bioimaging due to their low toxicity and ability to penetrate cells.
This study details the functionalization of CNOs with a specific BODIPY dye, enabling fluorescent activity that can switch on/off in response to pH changes.
The switching mechanism is attributed to the photoinduced electron transfer (PET) attributes of the BODIPY dye.
Diagnostic applications increasingly rely on nanomaterials that can sense physiological changes in cells.
Fluorescent nanosensors are cost-effective and simple to operate, capable of generating optical responses to stimuli.
Intracellular pH is critical to cell health, with fluctuations indicating various cellular processes.
CNOs are an attractive class of carbon nanomaterials for imaging due to:
Low density and high surface area to volume ratio
Spherical shape allowing versatile functionalization
CNOs show low inflammatory response and cytotoxicity, with successful internalization into cancer cells.
The procedure includes:
Oxidation of CNOs using nitric acid to create carboxylic groups.
Reaction of oxidized CNOs with BODIPY dye to create fluorescently labeled CNOs (fluo-CNOs).
The modulation of fluorescence in fluo-CNOs is linked to protonation states of the dimethylamino group in the BODIPY:
Non-protonated form (BODIPY 3) exhibits lower fluorescence at 737 nm when pH is neutral or basic.
Protonated form (BODIPY 4) leads to enhanced fluorescence at 637 nm in acidic conditions.
The fast and reversible nature of the on/off fluorescence switching is ideal for pH-sensing applications.
Synthetic Schemes:
Scheme 1: Details the BODIPY synthesis.
Scheme 2: Illustrates the preparation of oxidized CNOs.
Photophysical Properties:
Emission spectra confirm the switching between different BODIPY states upon changing pH.
Dynamic Light Scattering (DLS) indicated effective hydrodynamic diameters of oxi-CNOs and fluo-CNOs.
Confocal Microscopy studies demonstrate successful internalization and pH-triggered fluorescence in HeLa cells.
Fluo-CNOs showed moderate toxicity, with cell viability above 80% across various concentrations.
Impacts on HeLa cells further emphasize the materials' suitability for use as intracellular sensors.
BODIPY-CNO probes were synthesized and demonstrated rapid fluorescence modulation based on pH changes.
The potential applications of these probes in biological sensing highlight their relevance in diagnostics.
Characterization Techniques: Include TGA, Raman spectroscopy, fluorescence spectroscopy, DLS, and NMR spectroscopy to assess the compounds.
Cell Culture: HeLa cells were maintained and assessed for cytotoxicity using standard protocols.
2190-4286-8-188
Carbon nano-onions (CNOs) are highlighted as promising agents for bioimaging due to their low toxicity and ability to penetrate cells.
This study details the functionalization of CNOs with a specific BODIPY dye, enabling fluorescent activity that can switch on/off in response to pH changes.
The switching mechanism is attributed to the photoinduced electron transfer (PET) attributes of the BODIPY dye.
Diagnostic applications increasingly rely on nanomaterials that can sense physiological changes in cells.
Fluorescent nanosensors are cost-effective and simple to operate, capable of generating optical responses to stimuli.
Intracellular pH is critical to cell health, with fluctuations indicating various cellular processes.
CNOs are an attractive class of carbon nanomaterials for imaging due to:
Low density and high surface area to volume ratio
Spherical shape allowing versatile functionalization
CNOs show low inflammatory response and cytotoxicity, with successful internalization into cancer cells.
The procedure includes:
Oxidation of CNOs using nitric acid to create carboxylic groups.
Reaction of oxidized CNOs with BODIPY dye to create fluorescently labeled CNOs (fluo-CNOs).
The modulation of fluorescence in fluo-CNOs is linked to protonation states of the dimethylamino group in the BODIPY:
Non-protonated form (BODIPY 3) exhibits lower fluorescence at 737 nm when pH is neutral or basic.
Protonated form (BODIPY 4) leads to enhanced fluorescence at 637 nm in acidic conditions.
The fast and reversible nature of the on/off fluorescence switching is ideal for pH-sensing applications.
Synthetic Schemes:
Scheme 1: Details the BODIPY synthesis.
Scheme 2: Illustrates the preparation of oxidized CNOs.
Photophysical Properties:
Emission spectra confirm the switching between different BODIPY states upon changing pH.
Dynamic Light Scattering (DLS) indicated effective hydrodynamic diameters of oxi-CNOs and fluo-CNOs.
Confocal Microscopy studies demonstrate successful internalization and pH-triggered fluorescence in HeLa cells.
Fluo-CNOs showed moderate toxicity, with cell viability above 80% across various concentrations.
Impacts on HeLa cells further emphasize the materials' suitability for use as intracellular sensors.
BODIPY-CNO probes were synthesized and demonstrated rapid fluorescence modulation based on pH changes.
The potential applications of these probes in biological sensing highlight their relevance in diagnostics.
Characterization Techniques: Include TGA, Raman spectroscopy, fluorescence spectroscopy, DLS, and NMR spectroscopy to assess the compounds.
Cell Culture: HeLa cells were maintained and assessed for cytotoxicity using standard protocols.