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Photophysical properties and fluorescence lifetime imaging of exfoliated near-infrared fluorescent silicate nanosheets

 
: Selvaggio, Gabriele; Weitzel, Milan; Oleksiievets, Nazar; Oswald, Tabea A.; Nißler, Robert; Mey, Ingo; Karius, Volker; Enderlein, Jörg; Tsukanov, Roman; Kruss, Sebastian

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Volltext ()

Nanoscale advances 3 (2021), Nr.15, S.4541-4553
ISSN: 2516-0230
Deutsche Forschungsgemeinschaft DFG
390677874; RESOLV
EXC 2033: Ruhr Explores Solvation : Physik der kondensierten Materie
Deutsche Forschungsgemeinschaft DFG
437021944
Nah-Infrarot fluoreszente Nanomaterialien: Von der Photophysik, über funktionale Grenzflächen bis zu Biosensoren
Deutsche Forschungsgemeinschaft DFG
390729940
EXC 2067: Multiscale Bioimaging: Von molekularen Maschinen zu Netzwerken erregbarer Zellen
Englisch
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IMS ()
fluorescence lifetime imaging; fluorescence lifetime; layered silicate; macroscopic scale; multicolor imaging; near-infrared (NIR); photophysical properties; remote imaging

Abstract
The layered silicates Egyptian Blue (CaCuSi4O10, EB), Han Blue (BaCuSi4O10, HB) and Han Purple (BaCuSi2O6, HP) emit as bulk materials bright and stable fluorescence in the near-infrared (NIR), which is of high interest for (bio)photonics due to minimal scattering, absorption and phototoxicity in this spectral range. So far the optical properties of nanosheets (NS) of these silicates are poorly understood. Here, we exfoliate them into monodisperse nanosheets, report their physicochemical properties and use them for (bio)photonics. The approach uses ball milling followed by tip sonication and centrifugation steps to exfoliate the silicates into NS with lateral size and thickness down to ≈ 16–27 nm and 1–4 nm, respectively. They emit at ≈ 927 nm (EB-NS), 953 nm (HB-NS) and 924 nm (HP-NS), and single NS can be imaged in the NIR. The fluorescence lifetimes decrease from ≈ 30–100 μs (bulk) to 17 μs (EB-NS), 8 μs (HB-NS) and 7 μs (HP-NS), thus enabling lifetime-encoded multicolor imaging both on the microscopic and the macroscopic scale. Finally, remote imaging through tissue phantoms reveals the potential for bioimaging. In summary, we report a procedure to gain monodisperse NIR fluorescent silicate nanosheets, determine their size-dependent photophysical properties and showcase the potential for NIR photonics.

: http://publica.fraunhofer.de/dokumente/N-638669.html