Unlocking NIR‐II Photoluminescence in 2D Copper Tetrasilicate Nanosheets through Flame Spray Synthesis
Abstract
Abstract Expanding fluorescence bioimaging into the second near‐infrared spectrum (NIR‐II, 1000–1700 nm) unlocks advanced possibilities for diagnostics and therapeutics, offering superior tissue penetration and resolution. 2D copper tetrasilicate (CTS) pigments ( M CuSi 4 O 10 , M = Ca, Sr, Ba) are known for their brightness and stability, yet synthetic challenges have curbed their integration into bioimaging. Here, flame‐spray‐pyrolysis (FSP) is introduced as a versatile and scalable synthesis approach to produce ultra‐bright, metastable CTS nanosheets (NS) by annealing multi‐element metal oxide nanoparticles into 2D crystals through calcination or laser irradiation. Group‐II ion incorporation shifts emission into the NIR‐II range, with Ba 0.33 Sr 0.33 Ca 0.33 CuSi 4 O 10 peaking at 1007 nm, while minor Mg‐doping induces a hypsochromic shift and extends fluorescence lifetimes. The engineered CTS achieves quantum yields of up to 34%, supporting NS high‐frame‐rate imaging (> 200 fps). These unique properties enable CTS‐NS to serve as powerful contrast agents for super‐resolution NIR bioimaging, demonstrated in vivo through transcranial microcirculation mapping and macrophage tracking in mice using diffuse optical localization imaging (DOLI). This pioneering synthesis strategy unlocks wavelength‐tunable NS for advanced NIR‐II bioimaging applications.
Article Details
Authors (13)
Robert Nißler
Nanoparticle Systems Engineering Laboratory Institute of Energy and Process Engineering (IEPE) Department of Mechanical and Process Engineering (D‐MAVT) ETH Zurich Sonneggstrasse 3 Zurich 8092 Switzerland
Quanyu Zhou
Björn Hill
Department of Chemistry Bochum University Universitätsstraße 150 44801 Bochum Germany
Sabrina L.J. Thomä
Center for X‐ray Analytics Swiss Federal Laboratories for Materials Science and Technology (Empa) Ueberlandstrasse 143 Dübendorf 8600 Switzerland
Lukas R.H. Gerken
Nanoparticle Systems Engineering Laboratory Institute of Energy and Process Engineering (IEPE) Department of Mechanical and Process Engineering (D‐MAVT) ETH Zurich Sonneggstrasse 3 Zurich 8092 Switzerland
Aurelio Borzi
Center for X‐ray Analytics Swiss Federal Laboratories for Materials Science and Technology (Empa) Ueberlandstrasse 143 Dübendorf 8600 Switzerland
Kevin Roost
Nanoparticle Systems Engineering Laboratory Institute of Energy and Process Engineering (IEPE) Department of Mechanical and Process Engineering (D‐MAVT) ETH Zurich Sonneggstrasse 3 Zurich 8092 Switzerland
Benjamin Mächler
Nanoparticle Systems Engineering Laboratory Institute of Energy and Process Engineering (IEPE) Department of Mechanical and Process Engineering (D‐MAVT) ETH Zurich Sonneggstrasse 3 Zurich 8092 Switzerland
Xosé Luís Deán‐Ben
Institute for Biomedical Engineering Department of Information Technology and Electrical Engineering ETH Zürich Zürich 8093 Switzerland
Antonia Neels
Sebastian Kruss
Daniel Razansky
Department of Information Technology and Electrical Engineering, Institute for Biomedical Engineering, ETH Zurich
Inge K. Herrmann
Nanoparticle Systems Engineering Laboratory Institute of Energy and Process Engineering (IEPE) Department of Mechanical and Process Engineering (D‐MAVT) ETH Zurich Sonneggstrasse 3 Zurich 8092 Switzerland