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Silica nanoparticles with thermally activated delayed fluorescence for live cell imaging.

Crucho, Carina I.C. and Avó, João and Nobuyasu, Roberto and N. Pinto, Sandra and Fernandes, Fábio and Lima, João C. and Berberan-Santos, Mário N. and Dias, Fernando B. (2020) 'Silica nanoparticles with thermally activated delayed fluorescence for live cell imaging.', Materials science and engineering : C., 109 . p. 110528.


Thermally activated delayed fluorescence (TADF) has revolutionized the field of organic light emitting diodes owing to the possibility of harvesting non-emissive triplet states and converting them in emissive singlet states. This mechanism generates a long-lived delayed fluorescence component which can also be used in sensing oxygen concentration, measuring local temperature, or on imaging. Despite this strong potential, only recently TADF has emerged as a powerful tool to develop metal-free long-lived luminescent probes for imaging and sensing. The application of TADF molecules in aqueous and/or biological media requires specific structural features that allow complexation with biomolecules or enable emission in the aggregated state, in order to retain the delayed fluorescence that is characteristic of these compounds. Herein we demonstrate a facile method that maintains the optical properties of solvated dyes by dispersing TADF molecules in nanoparticles. TADF dye-doped silica nanoparticles are prepared using a modified fluorescein fluorophore. However, the strategy can be used with many other TADF dyes. The covalent grafting of the TADF emitter into the inorganic matrix effectively preserves and transfers the optical properties of the free dye into the luminescent nanomaterials. Importantly, the silica matrix is efficient in shielding the dye from solvent polarity effects and increases delayed fluorescence lifetime. The prepared nanoparticles are effectively internalized by human cells, even at low incubation concentrations, localizing primarily in the cytosol, enabling fluorescence microscopy imaging at low dye concentrations.

Item Type:Article
Full text:(AM) Accepted Manuscript
Available under License - Creative Commons Attribution Non-commercial No Derivatives.
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Publisher statement:© 2019 This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Date accepted:05 December 1999
Date deposited:10 December 2019
Date of first online publication:06 December 2019
Date first made open access:06 December 2020

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