Premium
Triplet– T riplet Annihilation Upconversion Based Nanocapsules for Bioimaging Under Excitation by Red and Deep‐ R ed Light
Author(s) -
Wohnhaas Christian,
Mailänder Volker,
Dröge Melanie,
Filatov Mikhail A.,
Busko Dmitry,
Avlasevich Yuri,
Baluschev Stanislav,
Miteva Tzenka,
Landfester Katharina,
Turshatov Andrey
Publication year - 2013
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.201300149
Subject(s) - photon upconversion , nanocapsules , fluorescence , materials science , excitation , optoelectronics , photochemistry , chemistry , nanotechnology , analytical chemistry (journal) , nanoparticle , optics , luminescence , physics , chromatography , quantum mechanics
Non‐toxic and biocompatible triplet–triplet annihilation upconversion based nanocapsules (size less than 225 nm) were successfully fabricated by the combination of miniemulsion and solvent evaporation techniques. A first type of nanocapsules displays an upconversion spectrum characterized by the maximum of emission at λ max = 550 nm under illumination by red light, λ exc = 633 nm. The second type of nanocapsules fluoresces at λ max = 555 nm when excited with deep‐red light, λ exc = 708 nm. Conventional confocal laser scanning microscopy (CLSM) and flow cytometry were applied to determine uptake and toxicity of the nanocapsules for various (mesenchymal stem and HeLa) cells. Red light ( λ exc = 633 nm) with extremely low optical power (less than 0.3 μW) or deep‐red light ( λ exc = 708 nm) was used in CLSM experiments to generate green upconversion fluorescence. The cell images obtained with upconversion excitation demonstrate order of magnitude better signal to background ratio than the cell images obtained with direct excitation of the same fluorescence marker.