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Silica nanoparticles with thermally activated delayed fluorescence for live cell imaging

Crucho, Carina I.C.; Avó, João; Nobuyasu, Roberto; N. Pinto, Sandra; Fernandes, Fábio; Lima, João C.; Berberan-Santos, Mário N.; Dias, Fernando B.

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Carina I.C. Crucho

João Avó

Roberto Nobuyasu

Sandra N. Pinto

Fábio Fernandes

João C. Lima

Mário N. Berberan-Santos


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.


Crucho, C. I., Avó, J., Nobuyasu, R., N. Pinto, S., Fernandes, F., Lima, J. C., …Dias, F. B. (2020). Silica nanoparticles with thermally activated delayed fluorescence for live cell imaging. Materials Science and Engineering: C, 109, Article 110528.

Journal Article Type Article
Acceptance Date Dec 5, 1999
Online Publication Date Dec 6, 2019
Publication Date Apr 30, 2020
Deposit Date Dec 10, 2019
Publicly Available Date Dec 6, 2020
Journal Materials Science and Engineering: C
Print ISSN 0928-4931
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 109
Article Number 110528


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